The Clinician Assessment of Fluctuation and the One Day Fluctuation Assessment Scale. Two methods to assess fluctuating confusion in dementia

Outcomes of Patients With Mild Cognitive Impairment With Lewy Bodies or Alzheimer Disease at 3 and 5 Years After Diagnosis

BACKGROUND AND OBJECTIVES

Retrospective studies indicate that dementia with Lewy bodies (DLB) may be preceded by a mild cognitive impairment (MCI) prodrome. Research criteria for the prospective identification of MCI with Lewy bodies (MCI-LB) have been developed. We aimed to assess the prognosis of a prospectively identified MCI-LB cohort at 2 key milestones, 3- and 5 years after diagnosis, to examine classification stability over time and rates of adverse outcomes (dementia or death).

METHODS

This was a retrospective examination of data from 2 longitudinal observational cohort studies where participants with MCI were prospectively recruited from North East England and differentially classified as MCI due to Alzheimer disease (MCI-AD), possible MCI-LB, or probable MCI-LB. Adverse outcomes (DLB/other dementia or death) and stability of disease-specific classifications were examined in each group.

RESULTS

Of 152 participants with baseline MCI (54 MCI-AD, 29 possible MCI-LB, and 69 probable MCI-LB), 126 were followed for up to 3 years (mean age 75.3 years; 40% female). We found that prospective probable MCI-LB classifications were both sensitive (91%) and specific (94%) to classifications either remaining as probable MCI-LB or progressing to DLB (in some cases autopsy confirmed) for 3 or more years after. Classifications were at least as stable as those in MCI-AD. In this cohort with disease-specific MCI classifications, rates of progression to dementia were high: 55% of MCI-LB had developed DLB within 3 years. Dementia occurred in 47% of MCI-AD over the same duration (odds ratio 1.68, 95% CI 0.66-4.26, p = 0.278). Premature death was a common competing risk, occurring in 9% of MCI-AD and 11% of MCI-LB within 3 years.

DISCUSSION

These findings support that prospectively identified probable MCI-LB is a prodromal presentation of DLB and that disease-specific classifications of MCI may reliably identify different prodromal dementias.

Caregiver Experiences and Burden in Moderate-Advanced Dementia With Lewy Bodies

Background and Objectives

Dementia with Lewy bodies (DLB) is a common degenerative dementia, but research on caregiver experiences in late stages is lacking. This study aimed to investigate the caregiving experience in moderate-advanced DLB to identify opportunities for improving care and support.

Methods

Dyads of individuals with moderate-advanced DLB and their primary informal caregivers were recruited from specialty clinics, advocacy organizations, and research registries. The study collected demographics, disease-related measures, and measures of the caregiver experience relating to caregiver support, burden, grief, self-efficacy, depression, quality of life, and coping. Spearman correlation coefficients and Wilcoxon rank-sum tests evaluated the relationships of caregiver measures with patient and caregiver variables with adjustments for multiple testing.

Results

Caregivers (n = 143) were mostly women (83.5%) and spouses (84.7%) (mean age 68 years; range 37-85). Almost 40% reported high burden and/or depression. Caregiver measures correlated with fluctuation and behavioral symptom severity, sleepiness, and autonomic symptoms of the person with DLB. Higher burden correlated with worse caregiver quality of life, higher depression, and grief. Greater self-efficacy, social support, and resilience correlated with lower caregiver burden. The most frequently reported caregiver concerns were being unable to plan for the future, having to put the needs of the person with DLB ahead of the caregiver's own needs, and worry that the person with DLB would become too dependent on the caregiver, but many additional concerns were endorsed. Caregivers were generally satisfied with medical team support. The lowest reported satisfaction related to information regarding disease progression and how well medical teams shared information with each other.

Discussion

Various patient-related and caregiver-related factors influence caregiver experiences in moderate-advanced DLB. Clinicians can target caregiver needs by providing support resources and DLB education and treating bothersome patient symptoms. Future research should investigate what interventions can modify and improve caregiver experiences in advanced DLB and identify therapeutics for patient symptoms currently without adequate treatments (e.g., fluctuations, daytime sleepiness).

Trial Registration Information

NCT04829656.

Sustained attention in mild cognitive impairment with Lewy bodies and Alzheimer's disease

OBJECTIVE

Attentional impairments are common in dementia with Lewy bodies and its prodromal stage of mild cognitive impairment (MCI) with Lewy bodies (MCI-LB). People with MCI may be capable of compensating for subtle attentional deficits in most circumstances, and so these may present as occasional lapses of attention. We aimed to assess the utility of a continuous performance task (CPT), which requires sustained attention for several minutes, for measuring attentional performance in MCI-LB in comparison to Alzheimer's disease (MCI-AD), and any performance deficits which emerged with sustained effort.

METHOD

We included longitudinal data on a CPT sustained attention task for 89 participants with MCI-LB or MCI-AD and 31 healthy controls, estimating ex-Gaussian response time parameters, omission and commission errors. Performance trajectories were estimated both cross-sectionally (intra-task progress from start to end) and longitudinally (change in performance over years).

RESULTS

While response times in successful trials were broadly similar, with slight slowing associated with clinical parkinsonism, those with MCI-LB made considerably more errors. Omission errors were more common throughout the task in MCI-LB than MCI-AD (OR 2.3, 95% CI: 1.1-4.7), while commission errors became more common after several minutes of sustained attention. Within MCI-LB, omission errors were more common in those with clinical parkinsonism (OR 1.9, 95% CI: 1.3-2.9) or cognitive fluctuations (OR 4.3, 95% CI: 2.2-8.8).

CONCLUSIONS

Sustained attention deficits in MCI-LB may emerge in the form of attentional lapses leading to omissions, and a breakdown in inhibitory control leading to commission errors.

Who am I with my Lewy bodies? The insula as a core region of the self-concept networks

BACKGROUND

Dementia with Lewy bodies (DLB) is characterized by insular atrophy, which occurs at the early stage of the disease. Damage to the insula has been associated with disorders reflecting impairments of the most fundamental components of the self, such as anosognosia, which is a frequently reported symptom in patients with Lewy bodies (LB). The purpose of this study was to investigate modifications of the self-concept (SC), another component of the self, and to identify neuroanatomical correlates, in prodromal to mild DLB.

METHODS

Twenty patients with prodromal to mild DLB were selected to participate in this exploratory study along with 20 healthy control subjects matched in terms of age, gender, and level of education. The Twenty Statements Test (TST) was used to assess the SC. Behavioral performances were compared between LB patients and control subjects. Three-dimensional magnetic resonance images (MRI) were acquired for all participants and correlational analyses were performed using voxel-based morphometry (VBM) in whole brain and using a mask for the insula.

RESULTS

The behavioral results on the TST showed significantly impaired performances in LB patients in comparison with control subjects (p < .0001). Correlational analyses using VBM revealed positive correlations between the TST and grey matter volume within insular cortex, right supplementary motor area, bilateral inferior temporal gyri, right inferior frontal gyrus, and left lingual gyrus, using a threshold of p = .001 uncorrected, including total intracranial volume (TIV), age, and MMSE as nuisance covariates. Additionally, correlational analysis using a mask for the insula revealed positive correlation with grey matter volume within bilateral insular cortex, using a threshold of p = .005.

CONCLUSIONS

The behavioral results confirm the existence of SC impairments in LB patients from the prodromal stage of the disease, compared to matched healthy controls. As we expected, VBM analyses revealed involvement of the insula, among that of other brain regions, already known to be involved in other self-components. While this study is exploratory, our findings provide important insights regarding the involvement of the insula within the self, confirming the insula as a core region of the self-networks, including for high-order self-representations such as the SC.

Patient- and proxy-reported quality of life in advanced dementia with Lewy bodies

INTRODUCTION

Little is known regarding quality of life (QoL) in dementia with Lewy bodies (DLB), particularly in advanced stages.

METHODS

Dyads of individuals with moderate-advanced DLB and their primary caregivers were recruited from specialty clinics, advocacy organizations, and research registries. The study collected demographics, disease-related measures, and measures of patient/caregiver experiences.

RESULTS

The Quality of Life in Alzheimer's Disease (QoL-AD) was completed by the person with DLB and the caregiver (proxy) in 61 dyads; 85 dyads had only a proxy-completed QoL-AD. Patient- and proxy-reported scores were moderately correlated (r = 0.57, P < 0.0001). Worse patient-reported QoL correlated with daytime sleepiness, autonomic symptom burden, and behavioral symptoms. Proxy ratings correlated with dementia severity, daytime sleepiness, behavioral symptoms, dependence in activities of daily living, and caregiver experience measures.

DISCUSSION

Patient- and proxy-reported quality of life (QoL) should be assessed separately in advanced DLB. Some symptoms associated with QoL have available therapeutic options. Research is needed regarding strategies to optimally improve QoL in DLB.

HIGHLIGHTS

Patient and proxy quality of life (QoL) ratings had moderate correlation in advanced dementia with Lewy bodies. Daytime sleepiness affected patient- and proxy-reported QoL. Behavioral symptoms affected patient- and proxy-reported QoL. Autonomic symptom burden affected patient-reported QoL. Dementia severity, dependence, and caregiver experiences affected proxy ratings.

Ecological validity of cognitive fluctuations in dementia with Lewy bodies

OBJECTIVES

Cognitive fluctuations are a core clinical feature of dementia with Lewy bodies (DLB), but their contribution to the everyday functioning difficulties evident DLB are not well understood. The current study evaluated whether intraindividual variability across a battery of neurocognitive tests (intraindividual variability-dispersion) and daily cognitive fluctuations as measured by informant report are associated with worse daily functioning in DLB.

METHODS

The study sample included 97 participants with consensus-defined DLB from the National Alzheimer's Coordinating Center (NACC). Intraindividual variability-dispersion was measured using the coefficient of variation, which divides the standard deviation of an individual's performance scores across 12 normed neurocognitive indices from the NACC neuropsychological battery by that individual's performance mean. Informants reported on daily cognitive fluctuations using the Mayo Fluctuations Scale (MFS) and on daily functioning using the functional activities questionnaire (FAQ).

RESULTS

Logistic regression identified a large univariate association of intraindividual variability-dispersion and presence of daily cognitive fluctuations on the MFS (Odds Ratio = 73.27, 95% Confidence Interval = 1.38, 3,895.05). Multiple linear regression demonstrated that higher intraindividual variability-dispersion and presence of daily cognitive fluctuations as assessed by the MFS were significantly and independently related to worse daily functioning (FAQ scores).

CONCLUSIONS

Among those with DLB, informant-rated daily cognitive fluctuations and cognitive fluctuations measured in the clinic (as indexed by intraindividual variability-dispersion across a battery of tests) were independently associated with poorer everyday functioning. These data demonstrate ecological validity in measures of cognitive fluctuations in DLB.

Search in the Periphery for Potential Inflammatory Biomarkers of Dementia with Lewy Bodies and Alzheimer's Disease

Background

Neuroinflammation, with altered peripheral proinflammatory cytokine production, plays a major role in the pathogenesis of neurodegenerative diseases, such as Alzheimer's disease (AD), while the role of inflammation in dementia with Lewy bodies (DLB) is less known and the results of different studies are often in disagreement.

Objective

The present study aimed to investigate the levels of TNFα and IL-6 in serum and supernatants, and the related DNA methylation in patients affected by DLB and AD compared to healthy controls (HCs), to clarify the role of epigenetic mechanisms of DNA promoter methylation on of pro-inflammatory cytokines overproduction.

Methods

Twenty-one patients with DLB and fourteen with AD were frequency-matched for age and sex with eleven HCs. Clinical evaluation, TNFα and IL-6 gene methylation status, cytokine gene expression levels and production in serum and peripheral blood mononuclear cell (PBMC) supernatants were performed.

Results

In AD and DLB patients, higher serum levels of IL-6 and TNFα were detected than in HCs. Differences in LPS-stimulated versus spontaneous PBMCs were observed between DLB, AD, and HC in the levels of TNFα (p = 0.027) and IL-6 (p < 0.001). Higher levels were also revealed for sIL-6R in DLB (p < 0.001) and AD (p < 0.001) in comparison with HC.DNA hypomethylation in IL-6 and TNFα CpG promoter sites was detected for DLB and AD patients compared to the corresponding site in HCs.

Conclusions

Our preliminary study documented increased levels of IL-6 and TNFα in DLB and AD patients to HCs. This overproduction can be due to epigenetic mechanisms regarding the hypomethylation of DNA promoters.

Is the cingulate island sign a marker for early dementia conversion in Parkinson's disease?

BACKGROUND

To investigate whether the cingulate island sign (CIS) ratio (i.e., the ratio of regional uptake in the posterior cingulate cortex relative to the precuneus and cuneus on cerebral perfusion scans) is associated with early dementia conversion in Parkinson's disease (PD).

METHODS

We enrolled 226 patients with newly diagnosed PD and 48 healthy controls who underwent dual-phase 18 F-FP-CIT PET scans. Patients with PD were classified into three groups according to the CIS ratio on early-phase 18 F-FP-CIT PET images: a PD group with CIS or high CIS ratios (PD-CIS; n = 96), a PD group with inverse CIS or low CIS ratios (PD-iCIS; n = 40), and a PD group consisting of the remaining patients with normal CIS ratios (PD-nCIS; n = 90). We compared the risk of dementia conversion within a 5-year time point between the groups.

RESULTS

There were no significant differences in age, sex, education, or baseline cognitive function between the PD groups. The PD-CIS group had higher Unified Parkinson's Disease Rating Scale (UPDRS) motor scores and more severely decreased dopamine transporter availability in the putamen. The PD-iCIS group had a smaller hippocampal volume compared with the other groups. The risk of dementia conversion in the PD-CIS group did not differ from that in the PD-iCIS and PD-nCIS groups. Meanwhile, the PD-iCIS group had a higher risk of dementia conversion than the PD-nCIS group.

CONCLUSION

The results of this study suggest that inverse CIS, rather than CIS, is relevant to early dementia conversion in patients with PD.

Clinical symptoms in mild cognitive impairment with Lewy bodies: Frequency, time of onset, and discriminant ability

BACKGROUND AND PURPOSE

Mild cognitive impairment with Lewy bodies (MCI-LB) is associated with a range of cognitive, motor, neuropsychiatric, sleep, autonomic, and visual symptoms. We investigated the cumulative frequency of symptoms in a longitudinal cohort of MCI-LB compared with MCI due to Alzheimer disease (MCI-AD) and analysed the ability of a previously described 10-point symptom scale to differentiate MCI-LB and MCI-AD, in an independent cohort.

METHODS

Participants with probable MCI-LB (n = 70), MCI-AD (n = 51), and controls (n = 34) had a detailed clinical assessment and annual follow-up (mean duration = 1.7 years). The presence of a range of symptoms was ascertained using a modified version of the Lewy Body Disease Association Comprehensive LBD Symptom Checklist at baseline assessment and then annually.

RESULTS

MCI-LB participants experienced a greater mean number of symptoms (24.2, SD = 7.6) compared with MCI-AD (11.3, SD = 7.4) and controls (4.2, SD = 3.1; p < 0.001 for all comparisons). A range of cognitive, parkinsonian, neuropsychiatric, sleep, and autonomic symptoms were significantly more common in MCI-LB than MCI-AD, although when present, the time of onset was similar between the two groups. A previously defined 10-point symptom scale demonstrated very good discrimination between MCI-LB and MCI-AD (area under the receiver operating characteristic curve = 0.91, 95% confidence interval = 0.84-0.98), replicating our previous finding in a new cohort.

CONCLUSIONS

MCI-LB is associated with the frequent presence of a particular profile of symptoms compared to MCI-AD. Clinicians should look for evidence of these symptoms in MCI and be aware of the potential for treatment. The presence of these symptoms may help to discriminate MCI-LB from MCI-AD.

Association between amyloid-beta deposition and cortical thickness in dementia with Lewy bodies

OBJECTIVE

Amyloid-beta often co-exists in dementia with Lewy bodies, but its clinical relevance in dementia with Lewy bodies remains unclear. This study aimed to investigate the clinical and imaging correlates of amyloid-beta deposition in dementia with Lewy bodies, particularly its relationship with cortical thickness in Alzheimer's disease-prone regions and hippocampal volume.

METHODS

Twenty-four participants with probable dementia with Lewy bodies underwent high-resolution magnetic resonance imaging and amyloid-beta positron emission tomography imaging using the radiotracer ¹⁸F-NAV4694. Amyloid-beta deposition was quantified and reported using the Centiloid method.

RESULTS

Amyloid-beta positivity, defined as Centiloid > 50, was present in 45.8% of dementia with Lewy bodies participants. There were no statistically significant differences in clinical characteristics between Aβ+ and Aβ- dementia with Lewy bodies. Compared with the Aβ- group, Aβ+ dementia with Lewy bodies exhibited greater global cortical thinning as well as in the Alzheimer's disease-prone region of interest, adjusted for age, sex and years of education. A mean cortical thickness of 5.12 mm across a combined meta-region of interest has a sensitivity of 88.9% and specificity of 90.0% in discriminating Aβ+ from Aβ- dementia with Lewy bodies. Hippocampal volume was not different between groups.

CONCLUSION

Early structural changes in cortical thickness, but not hippocampal volume, were observed in dementia with Lewy bodies with significant amyloid-beta burden. This may represent an early Alzheimer's disease-related neurodegenerative process.

Disease progression in dementia with Lewy bodies: A longitudinal study on clinical symptoms, quality of life and functional impairment

BACKGROUND AND OBJECTIVES

Dementia with Lewy Bodies (DLB) is a heterogeneous disease, with variable signs and symptoms across multiple domains. We aimed to identify associations with rate of change in cognition, everyday functioning (IADL) and quality of life (QoL).

METHODS

We included 121 DLB patients (69 ± 6 yrs, 14%F, MMSE: 25 ± 3) in our prospective cohort (follow-up 2 ± 1 yrs). We described progression of symptoms and cognitive decline over time. Mixed models were used to investigate whether changes in symptoms were associated to changes in IADL (FAQ), QoL (QoL-AD) and caregiver burden (ZBI). Last, we investigated whether baseline symptoms and biomarkers predicted decline in cognition (MMSE), IADL (FAQ) and QoL (QoL-AD).

RESULTS

Parkinsonism and RBD were most frequently present early in the disease course, while hallucinations were more likely to develop in a later stage. MMSE (annual change β ± SE = -2.06 ± 0.23), QoL-AD (-1.03 ± 0.20), and FAQ (3.04 ± 0.30) declined over time. Increasing severity of clinical symptoms was associated to increases in FAQ, QoL-AD and caregiver burden. Baseline clinical symptoms were not predictive for decline in these outcomes. By contrast, AD co-pathology (CSF pTau/Aβ42 ratio) was associated to steeper decline in MMSE (-1.23 ± 0.54). Medial temporal atrophy (-0.81 ± 0.26) and global cortical atrophy (-0.73 ± 0.36) predisposed for decline in QoL-AD.

CONCLUSIONS

Our findings imply that underlying disease processes, rather than clinical symptomatology aid in predicting decline. These findings are relevant for treatment strategies and the development of DLB specific outcome measures.

Dispersion-based cognitive intra-individual variability in dementia with Lewy bodies

OBJECTIVE

Cognitive fluctuations are characteristic of dementia with Lewy bodies (DLB) but challenging to measure. Dispersion-based intra-individual variability (IIV-d) captures neurocognitive performance fluctuations across a test battery and may be sensitive to cognitive fluctuations but has not been studied in DLB.

METHOD

We report on 5,976 participants that completed the uniform data set 3.0 neuropsychological battery (UDS3NB). IIV-d was calculated via the intra-individual standard deviation across 12 primary UDS3NB indicators. Separate models using mean USD3NB score and the Montreal cognitive assessment (MoCA) total score tested the reproducibility of the incremental value of IIV-d over-and-above global cognition. Binary logistic regressions tested whether IIV-d could classify individuals with and without clinician-rated cognitive fluctuations. Multinomial logistic regressions tested whether IIV-d could differentiate participants with DLB, participants with Alzheimer's disease (AD), and participants with healthy cognition (CH), as well as the incremental diagnostic utility of IIV-d over-and-above clinician-rated cognitive fluctuations.

RESULTS

IIV-d exhibited large univariate associations with clinician-rated and non-clinician-informant reported cognitive fluctuations, which persisted when adjusting for MoCA but not the full battery mean. Of diagnostic relevance, greater IIV-d was consistently associated with DLB and AD relative to CH over-and-above global cognition and clinician-rated cognitive fluctuations. Greater IIV-d was less consistently associated with an increased probability of DLB relative to AD when controlling for global cognition.

CONCLUSIONS

IIV-d accurately differentiates DLB from CH over-and-above global cognition and clinician-rated cognitive fluctuations. IIV-d may supplement a thorough clinical interview of cognitive fluctuations and serve as a standardized performance-based indicator of this transdiagnostic phenomenon. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Neuropsychological Impairments and Their Cognitive Architecture in Mild Cognitive Impairment (MCI) with Lewy Bodies and MCI-Alzheimer's Disease

OBJECTIVE

The present study aimed to clarify the neuropsychological profile of the emergent diagnostic category of Mild Cognitive Impairment with Lewy bodies (MCI-LB) and determine whether domain-specific impairments such as in memory were related to deficits in domain-general cognitive processes (executive function or processing speed).

METHOD

Patients (n = 83) and healthy age- and sex-matched controls (n = 34) underwent clinical and imaging assessments. Probable MCI-LB (n = 44) and MCI-Alzheimer's disease (AD) (n = 39) were diagnosed following National Institute on Aging-Alzheimer's Association (NIA-AA) and dementia with Lewy bodies (DLB) consortium criteria. Neuropsychological measures included cognitive and psychomotor speed, executive function, working memory, and verbal and visuospatial recall.

RESULTS

MCI-LB scored significantly lower than MCI-AD on processing speed [Trail Making Test B: p = .03, g = .45; Digit Symbol Substitution Test (DSST): p = .04, g = .47; DSST Error Check: p < .001, g = .68] and executive function [Trail Making Test Ratio (A/B): p = .04, g = .52] tasks. MCI-AD performed worse than MCI-LB on memory tasks, specifically visuospatial (Modified Taylor Complex Figure: p = .01, g = .46) and verbal (Rey Auditory Verbal Learning Test: p = .04, g = .42) delayed recall measures. Stepwise discriminant analysis correctly classified the subtype in 65.1% of MCI patients (72.7% specificity, 56.4% sensitivity). Processing speed accounted for more group-associated variance in visuospatial and verbal memory in both MCI subtypes than executive function, while no significant relationships between measures were observed in controls (all ps > .05).

CONCLUSIONS

MCI-LB was characterized by executive dysfunction and slowed processing speed but did not show the visuospatial dysfunction expected, while MCI-AD displayed an amnestic profile. However, there was considerable neuropsychological profile overlap and processing speed mediated performance in both MCI subtypes.

Association between prevalence rate of dementia with Lewy bodies and sleep characteristics in Chinese old adults

Introduction: Few studies are available on the prevalence and sleep-related factors of dementia with Lewy bodies (DLB) in Chinese older adults, aiming to explore the associations between sleep characteristics and DLB.

Methods: A cross-sectional study with 7,528 individuals aged ≥65 years in 106 communities in Northern China was conducted from April 2019 to January 2020. Questionaries (including demographic characteristics, comorbidities, lifestyles, and sleep characteristics) were administered, and neuropsychological assessments and physical examination were conducted in phase I; screening for probable DLB was done in phase II. Logistic regressions were used to assess associations.

Results: A total of 919 (12.2%, 919/7,528) participants had dementia, and 101 (1.3%, 101/7,528) participants were diagnosed with DLB. The prevalence of dementia and DLB were slightly higher or equal in women, increased with age, and roughly decreased with nighttime sleep duration. Of the 101 participants, all of them (100.0%) had cognitive impairment, 46 (44.54%) displayed fluctuating cognition, 72 (71.29%) of them showed visual hallucination, 22 (21.78%) individuals reported RBD, and 27.71% showed Parkinsonism. Sleeping for <5 h (adjusted OR = 1.795, 95%CI: 1.055–3.054, p < 0.05) or having hypersomnolence (adjusted OR = 31.213, 95% CI: 17.618–55.301, p < 0.001) were significantly associated with the occurrence of DLB. Sleep duration of <5 h or >8 h had combined diagnostic value for DLB (AUC = 0.783, 95%CI: 0.734–0.831, p < 0.001).

Conclusions: The current prevalence of DLB is 1.3% in Northern China. Short or long nighttime sleep duration is independently associated with the occurrence of dementia and DLB.

Prodromal characteristics of dementia with Lewy bodies: baseline results of the MEMENTO memory clinics nationwide cohort

Background

Isolated subjective cognitive impairment (SCI) and mild cognitive impairment (MCI) are the prodromal phases of dementia with Lewy bodies (DLB). MEMENTO is a nationwide study of patients with SCI and MCI with clinic, neuropsychology, biology, and brain imaging data. We aimed to compare SCI and MCI patients with symptoms of prodromal DLB to others in this study at baseline.

Methods

Participants of the French MEMENTO cohort study were recruited for either SCI or MCI. Among them, 892 were included in the Lewy sub-study, designed to search specifically for symptoms of DLB. Probable prodromal DLB diagnosis (pro-DLB group) was done using a two-criteria cutoff score among the four core clinical features of DLB. This Pro-DLB group was compared to two other groups at baseline: one without any core symptoms (NS group) and the one with one core symptom (1S group). A comprehensive cognitive battery, questionnaires on behavior, neurovegetative and neurosensory symptoms, brain 3D volumetric MRI, CSF, FDG PET, and amyloid PET were done.

Results

The pro-DLB group comprised 148 patients (16.6%). This group showed more multidomain (59.8%) MCI with slower processing speed and a higher proportion of patients with depression, anxiety, apathy, constipation, rhinorrhea, sicca syndrome, and photophobia, compared to the NS group. The pro-DLB group had isolated lower P-Tau in the CSF (not significant after adjustments for confounders) and on brain MRI widening of sulci including fronto-insular, occipital, and olfactory sulci (FDR corrected), when compared to the NS group. Evolution to dementia was not different between the three groups over a median follow-up of 2.6 years.

Conclusions

Patients with symptoms of prodromal DLB are cognitively slower, with more behavioral disorders, autonomic symptoms, and photophobia. The occipital, fronto-insular, and olfactory bulb involvement on brain MRI was consistent with symptoms and known neuropathology. The next step will be to study the clinical, biological, and imaging evolution of these patients.

Trial registration

Clinicaltrials.gov, NCT01926249

Accuracy of the clinical diagnosis of dementia with Lewy bodies (DLB) among the Italian Dementia Centers: a study by the Italian DLB study group (DLB-SINdem)

Introduction

Dementia with Lewy bodies (DLB) may represent a diagnostic challenge, since its clinical picture overlaps with other dementia. Two toolkits have been developed to aid the clinician to diagnose DLB: the Lewy Body Composite Risk Score (LBCRS) and the Assessment Toolkit for DLB (AT-DLB). We aim to evaluate the reliability of these two questionnaires, and their ability to enhance the interpretation of the international consensus diagnostic criteria.

Methods

LBCRS and AT-DLB were distributed to 135 Italian Neurological Centers for Cognitive Decline and Dementia (CDCDs), with the indication to administer them to all patients with dementia referred within the subsequent 3 months. We asked to subsequently apply consensus criteria for DLB diagnosis, to validate the diagnostic accuracy of the two toolkits.

Results

A total of 23 Centers joined the study; 1854 patients were enrolled. We found a prevalence of possible or probable DLB of 13% each (26% total), according to the consensus criteria. LBCRS toolkit showed good reliability, with a Cronbach alpha of 0.77, stable even after removing variables from the construct. AT-DLB toolkit Cronbach alpha was 0.52 and, after the subtraction of the “cognitive fluctuation” criterion, was only 0.31. Accuracy, sensitivity, and specificity were higher for LBCRS vs. AT-DLB. However, when simultaneously considered in the logistic models, AT-DLB showed a better performance (p < 0.001). Overall, the concordance between LBCRS positive and AT-DLB possible/probable was of 78.02%

Conclusions

In a clinical setting, the LBCRS and AT-DLB questionnaires have good accuracy for DLB diagnosis.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10072-022-05987-z.

Elevated Plasma Orexin-A Levels in Prodromal Dementia with Lewy Bodies

BACKGROUND

Studies on plasma orexin-A levels in prodromal dementia with Lewy bodies (DLB) and the relationship with clinical manifestations are rare.

OBJECTIVE

To assess plasma orexin-A levels and evaluate the correlation with clinical features in patients with mild cognitive impairment with Lewy bodies (MCI-LB) and DLB.

METHODS

Plasma orexin-A levels were measured in 41 patients with MCI-LB, 53 with DLB, and 48 healthy controls (HCs). Informant-based history, neurological examinations, neuropsychological assessments, laboratory tests, and neuroimaging were collected and the correlation between orexin-A and various indicators evaluated.

RESULTS

Plasma orexin-A levels in patients with MCI-LB (1.18±0.33 ng/mL, p = 0.014) or DLB (1.20±0.44 ng/mL, p = 0.011) were significantly higher than in HCs (1.02±0.32 ng/mL) and associated with gender and age. DLB patients with fluctuating cognition (FC) (1.01±0.23 versus 1.31±0.50, p = 0.007) or parkinsonism (PARK) (0.98±0.19 versus 1.25±0.47, p = 0.030) had significantly lower plasma orexin-A levels than subjects without FC or PARK. Plasma orexin-A levels were significantly negatively correlated with irritability and UPDRS-III scores and significantly positively correlated with disinhibition scores.

CONCLUSION

This is the first report in which elevated plasma orexin-A levels were observed in patients with MCI-LB or DLB. In addition, lower orexin-A levels were found in patients with DLB and FC or PARK compared with HCs. The plasma orexin-A levels were associated with the presence of core features and motor and neuropsychiatric symptoms in patients with MCI-LB and DLB.

An adaptive measure of visuospatial impairment in Dementia with Lewy Bodies

Background

Dementia with Lewy bodies (DLB) is a common cause of dementia with poor prognosis and high hospitalization rates. DLB is frequently misdiagnosed, with clinical features that overlap significantly with other diseases including Parkinson's disease (PD). Clinical instruments that discriminate and track the progression of cognitive impairment in DLB are needed.

Objectives

The current study was designed to assess the utility of a mental rotation (MR) task for assessing visuospatial impairments in early DLB.

Methods

Accuracy of 22 DLB patients, 22 PD patients and 22 age‐matched healthy controls in the MR task were compared at comparing shapes with 0°, 45° and 90° rotations.

Results

Healthy controls and PD patients performed at similar levels while the DLB group were significantly impaired. Further, impairment in the visuospatial and executive function measures correlated with MR poor outcomes.

Conclusion

These findings support the MR task as an objective measure of visuospatial impairment with the ability to adjust difficulty to suit impairments in a DLB population. This would be a useful tool within clinical trials.

Clinical outcome measures in dementia with Lewy bodies trials: critique and recommendations

The selection of appropriate outcome measures is fundamental to the design of any successful clinical trial. Although dementia with Lewy bodies (DLB) is one of the most common neurodegenerative conditions, assessment of therapeutic benefit in clinical trials often relies on tools developed for other conditions, such as Alzheimer's or Parkinson's disease. These may not be sufficiently valid or sensitive to treatment changes in DLB, decreasing their utility. In this review, we discuss the limitations and strengths of selected available tools used to measure DLB-associated outcomes in clinical trials and highlight the potential roles for more specific objective measures. We emphasize that the existing outcome measures require validation in the DLB population and that DLB-specific outcomes need to be developed. Finally, we highlight how the selection of outcome measures may vary between symptomatic and disease-modifying therapy trials.

Mild cognitive impairment with Lewy bodies: neuropsychiatric supportive symptoms and cognitive profile

BACKGROUND

Recently published diagnostic criteria for mild cognitive impairment with Lewy bodies (MCI-LB) include five neuropsychiatric supportive features (non-visual hallucinations, systematised delusions, apathy, anxiety and depression). We have previously demonstrated that the presence of two or more of these symptoms differentiates MCI-LB from MCI due to Alzheimer's disease (MCI-AD) with a likelihood ratio >4. The aim of this study was to replicate the findings in an independent cohort.

METHODS

Participants ⩾60 years old with MCI were recruited. Each participant had a detailed clinical, cognitive and imaging assessment including FP-CIT SPECT and cardiac MIBG. The presence of neuropsychiatric supportive symptoms was determined using the Neuropsychiatric Inventory (NPI). Participants were classified as MCI-AD, possible MCI-LB and probable MCI-LB based on current diagnostic criteria. Participants with possible MCI-LB were excluded from further analysis.

RESULTS

Probable MCI-LB (n = 28) had higher NPI total and distress scores than MCI-AD (n = 30). In total, 59% of MCI-LB had two or more neuropsychiatric supportive symptoms compared with 9% of MCI-AD (likelihood ratio 6.5, p < 0.001). MCI-LB participants also had a significantly greater delayed recall and a lower Trails A:Trails B ratio than MCI-AD.

CONCLUSIONS

MCI-LB is associated with significantly greater neuropsychiatric symptoms than MCI-AD. The presence of two or more neuropsychiatric supportive symptoms as defined by MCI-LB diagnostic criteria is highly specific and moderately sensitive for a diagnosis of MCI-LB. The cognitive profile of MCI-LB differs from MCI-AD, with greater executive and lesser memory impairment, but these differences are not sufficient to differentiate MCI-LB from MCI-AD.

Dietary Inflammatory Index score and prodromal Parkinson's disease incidence: The HELIAD study

AIM

The aim of the present study was to investigate the association of the inflammatory potential of diet with prodromal Parkinson's disease (pPD) probability and incidence among community-dwelling older individuals without clinical features of parkinsonism at baseline.

METHODS

The sample consisted of 1,030 participants 65 years old or older, drawn from a population-based cohort study of older adults in Greece (Hellenic Longitudinal Investigation of Aging and Diet - HELIAD). We calculated pPD probability, according to International Parkinson and Movement Disorder Society research criteria. Dietary Inflammatory Index (DII) was used to measure the dietary inflammatory potential, with higher index score reflecting a more pro-inflammatory diet. Associations of baseline DII with pPD probability cross-sectionally, and with possible/probable pPD incidence (pPD probability ≥30%) during the follow-up period, were examined via general linear models and generalized estimating equations, respectively.

RESULTS

Cross-sectionally, one unit increase of DII score[DII (min, max) = -5.83, 6.01]was associated with 4.9% increased pPD probability [β=0.049, 95%CI (0.025-0.090), p<0.001]. Prospectively, 62 participants developed pPD during 3.1±0.9 (mean±SD) years of follow-up. One unit increase in DII was associated with 20.3% increased risk for developing pPD [RR=1.203, 95%CI (1.070-1.351), p=0.002]. Participants in the highest tertile of DII score were 2.6 times more likely to develop pPD [β=2.594, 95%CI (1.332-5.050), p=0.005], compared to those in the lowest tertile.

CONCLUSION

More pro-inflammatory diet was related with higher pPD probability and pPD incidence (pPD probability ≥30%) in a community-dwelling older adult population. Further studies are needed to confirm these findings.

Dynamic network impairments underlie cognitive fluctuations in Lewy body dementia

Cognitive fluctuations are a characteristic and distressing disturbance of attention and consciousness seen in patients with Dementia with Lewy bodies and Parkinson's disease dementia. It has been proposed that fluctuations result from disruption of key neuromodulatory systems supporting states of attention and wakefulness which are normally characterised by temporally variable and highly integrated functional network architectures. In this study, patients with DLB (n = 25) and age-matched controls (n = 49) were assessed using dynamic resting state fMRI. A dynamic network signature of reduced temporal variability and integration was identified in DLB patients compared to controls. Reduced temporal variability correlated significantly with fluctuation-related measures using a sustained attention task. A less integrated (more segregated) functional network architecture was seen in DLB patients compared to the control group, with regions of reduced integration observed across dorsal and ventral attention, sensorimotor, visual, cingulo-opercular and cingulo-parietal networks. Reduced network integration correlated positively with subjective and objective measures of fluctuations. Regions of reduced integration and unstable regional assignments significantly matched areas of expression of specific classes of noradrenergic and cholinergic receptors across the cerebral cortex. Correlating topological measures with maps of neurotransmitter/neuromodulator receptor gene expression, we found that regions of reduced integration and unstable modular assignments correlated significantly with the pattern of expression of subclasses of noradrenergic and cholinergic receptors across the cerebral cortex. Altogether, these findings demonstrate that cognitive fluctuations are associated with an imaging signature of dynamic network impairment linked to specific neurotransmitters/neuromodulators within the ascending arousal system, highlighting novel potential diagnostic and therapeutic approaches for this troubling symptom.

Quantifying test-retest reliability of repeated objective attentional measures in Lewy body dementia

Objective cognitive impairment is a feature of Lewy body dementia (LBD), and computerised attentional tasks are commonly used as outcome measures in interventional trials. However, the reliability of these measures, in the absence of interventions, are unknown. This study examined the reliability of these attentional measures at short-term and longer-term follow-up stages. LBD patients (n = 36) completed computerised attentional tasks [simple and choice reaction time, and digit vigilance (SRT, CRT, DV)] at short-term (Day 0–Day 5) and longer-term (4 and 12 weeks) follow-up. Intra-class correlations (ICCs) were calculated to assess test–retest reliability. At short-term, the reciprocal SRT, CRT and DV mean reaction time to correct answers, the reciprocal DV coefficient of variation, and reciprocal power of attention (PoA) all showed excellent levels of reliability (all ICCs > 0.90). The reciprocal PoA showed the highest level of reliability (ICC = 0.978). At longer-term follow-up, only the reciprocal PoA had excellent levels of reliability (ICC = 0.927). Reciprocal SRT, CRT and DV reaction time to correct answers, and the CRT coefficient of variation values, showed good levels of test–retest reliability (ICCs ≥ 0.85). Contrary to expectations, most attentional measures demonstrated high levels of test–retest reliability at both short-term and longer-term follow-up time points. The reciprocal PoA composite measure demonstrated excellent levels of test–retest reliability, both in the short-term and long-term. This indicates that objective attentional tasks are suitable outcome measures in LBD studies and that the composite PoA measure may offer the highest levels of reliability.

Reproductive factors and cognitive impairment in natural menopausal women: A cross-sectional study

INTRODUCTION

Little information on rural older women in northern China has been reported, apart from three studies in southern and eastern China in the past decade. This study aims to evaluate the relationships between reproductive factors and the risk of cognitive impairment, including mild cognitive impairment (MCI) and dementia, in Chinese women with natural menopause.

METHODS

The cross-sectional study was conducted in 112 community primary healthcare centers in rural northern China between April 2019 and January 2020. A total of 4,275 women aged ≥65 years who had natural menopause were included. Reproductive factors as well as the reproductive period (= age at menopause - age at menarche) were recorded. The relationships between reproductive factors and cognitive impairment were evaluated by correlation and logistic regression analysis.

RESULTS

Overall, 28.6% and 11.4% of women were diagnosed with MCI or dementia, respectively. In natural menopause women, the age at menopause (adjusted r = 0.070, p < 0.001), reproductive period (adjusted r = 0.053, p = 0.001), and number of pregnancies (adjusted r = -0.042, p = 0.007) and parities (adjusted r = -0.068, p < 0.001) were correlated with Mini-Mental State Examination (Chinese version) scores, and with similar findings concerning MCI and dementia with Lewy bodies (DLB). Greater age at menopause and a long reproductive period significantly decreased the risk of MCI and Alzheimer's disease (AD), and more parities significantly increased the risks of MCI (odds ratio (OR) = 1.111, 95% confidence interval (CI): 1.039-1.187, p = 0.002), dementia (OR = 1.162, 95% CI: 1.061-1.271, p = 0.001), particular AD (OR = 1.131, 95% CI: 1.010-1.266, p = 0.032), DLB (OR = 1.238, 95% CI: 1.003-1.528, p = 0.047), and vascular dementia (VaD) (OR = 1.288, 95% CI: 1.080-1.536, p = 0.005).

CONCLUSIONS

The prevalence rates of MCI and dementia were 28.6% and 11.4% in older women. Greater age at menarche, young age at menopause, shorter reproductive period, and larger numbers of pregnancies/parities were correlated with poor cognition and significantly increased the risks of MCI and dementia, particularly AD, DLB, and VaD.

Plasma Myeloperoxidase as a Potential Biomarker of Patient Response to Anti-Dementia Treatment in Alzheimer's Disease

BACKGROUND

Myeloperoxidase (MPO), a neutrophil-derived pro-inflammatory protein, co-localizes with amyloid-β (Aβ) plaques in Alzheimer's disease (AD). Anti-dementia treatment may facilitate efflux of Aβ and associated plaque proteins from the brain to the peripheral circulation, therefore providing potential biomarkers for the monitoring of donor response to drug treatment.

OBJECTIVE

We investigated the diagnostic utility of MPO as a biomarker of AD, and how anti-dementia treatment alters plasma MPO concentration.

METHODS

Thirty-two AD patients were recruited, and plasma collected pre-drug administration (baseline), and 1- and 6-months post-treatment. All patients received cholinesterase inhibitors (ChEIs). At baseline and 6 months, patients underwent neuropsychological assessment. Forty-nine elderly healthy individuals with normal cognitive status served as controls. Plasma MPO concentration was measured by ELISA.

RESULTS

AD drug naïve patients had similar plasma MPO concentration to their control counterparts (p > 0.05). Baseline MPO levels positively correlated with Neuropsychiatric Inventory score (r = 0.5080; p = 0.011) and carer distress (r = 0.5022; p = 0.012). Following 1-month ChEI treatment, 84.4% of AD patients exhibited increased plasma MPO levels (p < 0.001), which decreased at 6 months (p < 0.001). MPO concentration at 1 month was greatest in AD patients whose memory deteriorated during the study period (p = 0.028), and for AD patients with deterioration in Cornell assessment score (p = 0.044).

CONCLUSION

Whereas baseline MPO levels did not differentiate between healthy and AD populations, baseline MPO positively correlated with initial Neuropsychiatric Inventory evaluation. Post-treatment, transient MPO upregulation in ChEI-treated patients may reflect worse therapeutic outcome. Further studies are required to assess the potential of plasma MPO as an AD therapeutic biomarker.

Challenges in Predicting Cognitive Decline in Dementia with Lewy Bodies

Despite being the second most common form of neurodegenerative dementia, dementia with Lewy bodies (DLB) is under-recognized and carries a worse prognosis than other subtypes of the condition. Cognitive impairment is a cardinal feature of all types of dementia and DLB presents with a distinct profile with deficits in attention, executive function, and visuoperceptual abilities. This difference from Alzheimer's disease and the common presence of neuropsychiatric symptoms may lead to challenges in predicting cognitive decline in this patient population. Firstly, the diagnosis of DLB is often delayed in clinical practice leading to variability from which time point in the disease course cognitive decline is measured. Secondly, the most frequently used measurement tools for cognitive difficulties focus on memory and naming rather than the domains affected by DLB. While there is now largely a consensus which tools are useful in diagnosing DLB, their validity in assessing deteriorating cognition is less clear. Thirdly, the presence of fluctuating cognition, the propensity to develop delirium episodes, as well as difficulties in distinguishing the two entities in clinical practice make it difficult to predict the disease course. Sleep disturbances are likely to influence cognitive decline but require further study in patients within established DLB. Fourthly, as in most cases of dementia, neuropathological comorbidities are frequently present in DLB. While the influence of Alzheimer's pathology on cognitive decline in DLB is comparatively well understood, the impact of other pathologies remains unclear. The recent definition of research criteria for mild cognitive impairment in DLB could facilitate earlier diagnosis and more structured follow-up. Assessment tools measuring cognitive domains predominantly affected in DLB need to be more consistently used in longitudinal studies and clinical practice, as well as concurrent measures of fluctuations in cognition. Greater availability of biomarkers and digital healthcare solutions can play an important role in enabling more accurate monitoring and prediction of cognitive decline in DLB.

Effect of Levetiracetam on Cognition in Patients With Alzheimer Disease With and Without Epileptiform Activity: A Randomized Clinical Trial

Importance

Network hyperexcitability may contribute to cognitive dysfunction in patients with Alzheimer disease (AD).

Objective

To determine the ability of the antiseizure drug levetiracetam to improve cognition in persons with AD.

Design, Setting, and Participants

The Levetiracetam for Alzheimer's Disease-Associated Network Hyperexcitability (LEV-AD) study was a phase 2a randomized double-blinded placebo-controlled crossover clinical trial of 34 adults with AD that was conducted at the University of California, San Francisco, and the University of Minnesota, Twin Cities, between October 16, 2014, and July 21, 2020. Participants were adults 80 years and younger who had a Mini-Mental State Examination score of 18 points or higher and/or a Clinical Dementia Rating score of less than 2 points. Screening included overnight video electroencephalography and a 1-hour resting magnetoencephalography examination.

Interventions

Group A received placebo twice daily for 4 weeks followed by a 4-week washout period, then oral levetiracetam, 125 mg, twice daily for 4 weeks. Group B received treatment using the reverse sequence.

Main Outcomes and Measures

The primary outcome was the ability of levetiracetam treatment to improve executive function (measured by the National Institutes of Health Executive Abilities: Measures and Instruments for Neurobehavioral Evaluation and Research [NIH-EXAMINER] composite score). Secondary outcomes were cognition (measured by the Stroop Color and Word Test [Stroop] interference naming subscale and the Alzheimer's Disease Assessment Scale-Cognitive Subscale) and disability. Exploratory outcomes included performance on a virtual route learning test and scores on cognitive and functional tests among participants with epileptiform activity.

Results

Of 54 adults assessed for eligibility, 11 did not meet study criteria, and 9 declined to participate. A total of 34 adults (21 women [61.8%]; mean [SD] age, 62.3 [7.7] years) with AD were enrolled and randomized (17 participants to group A and 17 participants to group B). Thirteen participants (38.2%) were categorized as having epileptiform activity. In total, 28 participants (82.4%) completed the study, 10 of whom (35.7%) had epileptiform activity. Overall, treatment with levetiracetam did not change NIH-EXAMINER composite scores (mean difference vs placebo, 0.07 points; 95% CI, -0.18 to 0.32 points; P = .55) or secondary measures. However, among participants with epileptiform activity, levetiracetam treatment improved performance on the Stroop interference naming subscale (net improvement vs placebo, 7.4 points; 95% CI, 0.2-14.7 points; P = .046) and the virtual route learning test (t = 2.36; Cohen f2 = 0.11; P = .02). There were no treatment discontinuations because of adverse events.

Conclusions and Relevance

In this randomized clinical trial, levetiracetam was well tolerated and, although it did not improve the primary outcome, in prespecified analysis, levetiracetam improved performance on spatial memory and executive function tasks in patients with AD and epileptiform activity. These exploratory findings warrant further assessment of antiseizure approaches in AD.

Trial Registration

ClinicalTrials.gov Identifier: NCT02002819.

Intrinsic Alertness Is Impaired in Patients with Nigrostriatal Degeneration: A Prospective Study with Reference to [123I]FP-CIT SPECT and [18F]FDG PET

BACKGROUND

Variations in alertness and attention are common in Lewy body diseases (LBD) and among the core features of dementia with Lewy bodies (DLB). Dopamine transporter SPECT is an accurate biomarker of nigrostriatal degeneration (NSD) in LBD.

OBJECTIVE

The present study investigated performance on a computerized alertness test as a potential measure of attention in patients with NSD compared to patients without NSD.

METHODS

Thirty-six patients with cognitive impairment plus at least one core feature of DLB referred for [123I]FP-CIT SPECT imaging were prospectively recruited. Performance in a computerized test of intrinsic alertness was compared between patients with and those without NSD as assessed by [123I]FP-CIT SPECT.

RESULTS

Reaction times to auditory stimuli (adjusted for age, sex, and education) were significantly longer in patients with NSD compared to those with a normal [123I]FP-CIT SPECT scan (p < 0.05). Statistical analyses revealed no significant differences comparing reaction times to visual stimuli or dispersion of reaction times between groups. Exploratory analysis in a subgroup of patients with available [18F]FDG PET revealed that longer reaction times were associated with decreased glucose metabolism in the prefrontal cortex (statistical parametric mapping, adjusted for age and sex; p < 0.005, cluster extent > 50 voxels).

CONCLUSION

Computerized assessment of auditory reaction times is able to detect alertness deficits in patients with NSD and might help to measure alertness deficits in patients with LBD and NSD. Future studies in larger samples are needed to evaluate the diagnostic utility of computerized alertness assessment for the differential diagnosis of LBD.

Impaired sensory evidence accumulation and network function in Lewy body dementia

Deficits in attention underpin many of the cognitive and neuropsychiatric features of Lewy body dementia. These attention-related symptoms remain difficult to treat and there are many gaps in our understanding of their neurobiology. An improved understanding of attention-related impairments can be achieved via mathematical modelling approaches, which identify cognitive parameters to provide an intermediate level between observed behavioural data and its underlying neural correlate. Here, we apply this approach to identify the role of impaired sensory evidence accumulation in the attention deficits that characterize Lewy body dementia. In 31 people with Lewy body dementia (including 13 Parkinson's disease dementia and 18 dementia with Lewy bodies cases), 16 people with Alzheimer's disease, and 23 healthy controls, we administered an attention task whilst they underwent functional 3 T MRI. Using hierarchical Bayesian estimation of a drift-diffusion model, we decomposed task performance into drift rate and decision boundary parameters. We tested the hypothesis that the drift rate-a measure of the quality of sensory evidence accumulation-is specifically impaired in Lewy body dementia, compared to Alzheimer's disease. We further explored whether trial-by-trial variations in the drift rate related to activity within the default and dorsal attention networks, to determine whether altered activity in these networks was associated with slowed drift rates in Lewy body dementia. Our results revealed slower drift rates in the Lewy body dementia compared to the Alzheimer's disease group, whereas the patient groups were equivalent for their decision boundaries. The patient groups were reduced relative to controls for both parameters. This highlights sensory evidence accumulation deficits as a key feature that distinguishes attention impairments in Lewy body dementia, consistent with impaired ability to efficiently process information from the environment to guide behaviour. We also found that the drift rate was strongly related to activity in the dorsal attention network across all three groups, whereas the Lewy body dementia group showed a divergent relationship relative to the Alzheimer's disease and control groups for the default network, consistent with altered default network modulation being associated with impaired evidence accumulation. Together, our findings reveal impaired sensory evidence accumulation as a specific marker of attention problems in Lewy body dementia, which may relate to large-scale network abnormalities. By identifying impairments in a specific sub-process of attention, these findings will inform future exploratory and intervention studies that aim to understand and treat attention-related symptoms that are a key feature of Lewy body dementia.

Protocol for an observational cohort study identifying factors predicting accurately end of life in dementia with Lewy bodies and promoting quality end-of-life experiences: the PACE-DLB study

INTRODUCTION

Dementia with Lewy bodies (DLB) is one of the most common degenerative dementias. Despite the fact that most individuals with DLB die from complications of the disease, little is known regarding what factors predict impending end of life or are associated with a quality end of life.

METHODS AND ANALYSIS

This is a multisite longitudinal cohort study. Participants are being recruited from five academic centres providing subspecialty DLB care and volunteers through the Lewy Body Dementia Association (not receiving specialty care). Dyads must be US residents, include individuals with a clinical diagnosis of DLB and at least moderate-to-severe dementia and include the primary caregiver, who must pass a brief cognitive screen. The first dyad was enrolled 25 February 2021; recruitment is ongoing. Dyads will attend study visits every 6 months through the end of life or 3 years. Study visits will occur in-person or virtually. Measures include demographics, DLB characteristics, caregiver considerations, quality of life and satisfaction with end-of-life experiences. For dyads where the individual with DLB dies, the caregiver will complete a final study visit 3 months after the death to assess grief, recovery and quality of the end-of-life experience. Terminal trend models will be employed to identify significant predictors of approaching end of life (death in the next 6 months). Similar models will assess caregiver factors (eg, grief, satisfaction with end-of-life experience) after the death of the individual with DLB. A qualitative descriptive analysis approach will evaluate interview transcripts regarding end-of-life experiences.

ETHICS AND DISSEMINATION

This study was approved by the University of Florida institutional review board (IRB202001438) and is listed on clinicaltrials.gov (NCT04829656). Data sharing follows National Institutes of Health policies. Study results will be disseminated via traditional scientific strategies (conferences, publications) and through collaborating with the Lewy Body Dementia Association, National Institute on Aging and other partnerships.

Accuracy of dopaminergic imaging as a biomarker for mild cognitive impairment with Lewy bodies

BACKGROUND

Dopaminergic imaging is an established biomarker for dementia with Lewy bodies, but its diagnostic accuracy at the mild cognitive impairment (MCI) stage remains uncertain.

AIMS

To provide robust prospective evidence of the diagnostic accuracy of dopaminergic imaging at the MCI stage to either support or refute its inclusion as a biomarker for the diagnosis of MCI with Lewy bodies.

METHOD

We conducted a prospective diagnostic accuracy study of baseline dopaminergic imaging with [123I]N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl)nortropane single-photon emission computerised tomography (123I-FP-CIT SPECT) in 144 patients with MCI. Images were rated as normal or abnormal by a panel of experts with access to striatal binding ratio results. Follow-up consensus diagnosis based on the presence of core features of Lewy body disease was used as the reference standard.

RESULTS

At latest assessment (mean 2 years) 61 patients had probable MCI with Lewy bodies, 26 possible MCI with Lewy bodies and 57 MCI due to Alzheimer's disease. The sensitivity of baseline FP-CIT visual rating for probable MCI with Lewy bodies was 66% (95% CI 52-77%), specificity 88% (76-95%) and accuracy 76% (68-84%), with positive likelihood ratio 5.3.

CONCLUSIONS

It is over five times as likely for an abnormal scan to be found in probable MCI with Lewy bodies than MCI due to Alzheimer's disease. Dopaminergic imaging appears to be useful at the MCI stage in cases where Lewy body disease is suspected clinically.

Electroencephalogram in dementia with Lewy bodies: a systematic review

Dementia with Lewy bodies (DLB) belongs to the spectrum of Lewy body dementia (LBD) that also encompasses Parkinson's disease dementia (PDD). It is a common neurodegenerative disorder characterized by memory decline, cognitive fluctuations, visual hallucinations, autonomic nervous system disturbance, REM sleep behavior disorder, and parkinsonism. Definite diagnosis can be established only through neuropathological confirmation of Lewy bodies' presence in brain tissue. Probable or possible diagnosis relies upon clinical features, imaging, polysomnography, and electroencephalogram (EEG) findings. Potential neurophysiological biomarkers for the diagnosis, management, and evaluation of treatment-response in DLB should be affordable and widely available outside academic centers. Increasing evidence supports the use of quantitative EEG (qEEG) as a potential DLB biomarker, with promising results in discriminating DLB from other dementias and in identifying subjects who are on the trajectory to develop DLB. Several studies evaluated the diagnostic value of EEG in DLB. Visual analysis and qEEG techniques have been implemented, showing a superiority of the last in terms of sensitivity and objectivity. In this systematic review, we attempt to provide a general synthesis of the current knowledge on EEG application in DLB. We review the findings from original studies and address the issues remaining to be further clarified.

Measures of resting state EEG rhythms for clinical trials in Alzheimer's disease: Recommendations of an expert panel

The Electrophysiology Professional Interest Area (EPIA) and Global Brain Consortium endorsed recommendations on candidate electroencephalography (EEG) measures for Alzheimer's disease (AD) clinical trials. The Panel reviewed the field literature. As most consistent findings, AD patients with mild cognitive impairment and dementia showed abnormalities in peak frequency, power, and "interrelatedness" at posterior alpha (8-12 Hz) and widespread delta (< 4 Hz) and theta (4-8 Hz) rhythms in relation to disease progression and interventions. The following consensus statements were subscribed: (1) Standardization of instructions to patients, resting state EEG (rsEEG) recording methods, and selection of artifact-free rsEEG periods are needed; (2) power density and "interrelatedness" rsEEG measures (e.g., directed transfer function, phase lag index, linear lagged connectivity, etc.) at delta, theta, and alpha frequency bands may be use for stratification of AD patients and monitoring of disease progression and intervention; and (3) international multisectoral initiatives are mandatory for regulatory purposes.

Frailty and Prodromal Parkinson's Disease: Results From the HELIAD Study

BACKGROUND

To investigate the association between frailty, Parkinson's disease (PD), and the probability of prodromal Parkinson's disease (prodromal PD) in Greek community-dwelling older individuals.

METHODS

Parkinson's disease diagnosis was reached through standard clinical research procedures. Probability of prodromal PD was calculated according to the International Parkinson and Movement Disorder Society's research criteria for PD-free participants. Frailty was evaluated according to definitions of the phenotypic and multidomain approach. Logistic and linear regression models were performed to investigate associations between frailty (predictor) and the probability of prodromal PD, either continuous or dichotomous (≥30% probability score), or PD (outcome).

RESULTS

Data from 1765 participants aged 65 and older were included in the present analysis. Parkinson's disease and prodromal PD prevalence were 1.9% and 3.0%, respectively. Compared to nonfrail participants, those who were frail, as identified with either the Fried frailty phenotype or Frailty Index had approximately 4 (odds ratio [OR] 4.09, 95% confidence interval [CI] 1.54-10.89) and 12 times (OR 12.16, 95% CI 5.46-27.09) higher odds of having a PD diagnosis, respectively. Moreover, compared to the nonfrail, frail participants as identified with either the Fried frailty phenotype or Frailty Index had 2.8 (OR 2.83, 95% CI 1.09-7.37) and 8.3 times (OR 8.39, 95% CI 4.56-15.42) higher odds of having possible/probable prodromal PD, respectively.

CONCLUSIONS

Frailty status was associated with prodromal PD and PD, suggesting common characteristics or underlying mechanisms of these conditions. Although prospective studies are warranted, acknowledging the possible association of frailty, PD, and prodromal PD may improve their clinical management.

Characterization of symptoms and determinants of disease burden in dementia with Lewy bodies: DEvELOP design and baseline results

BACKGROUND

The DEmEntia with LEwy bOdies Project (DEvELOP) aims to phenotype patients with dementia with Lewy bodies (DLB) and study the symptoms and biomarkers over time. Here, we describe the design and baseline results of DEvELOP. We investigated the associations between core and suggestive DLB symptoms and different aspects of disease burden, i.e., instrumental activities of daily living (IADL) functioning, quality of life (QoL), and caregiver burden.

METHODS

We included 100 DLB patients (69 ± 6 years, 10%F, MMSE 25 ± 3) in the prospective DEvELOP cohort. Patients underwent extensive assessment including MRI, EEG/MEG, ¹²³FP-CIT SPECT, and CSF and blood collection, with annual follow-up. Core (hallucinations, parkinsonism, fluctuations, RBD) and suggestive (autonomous dysfunction, neuropsychiatric symptoms) symptoms were assessed using standardized questionnaires. We used multivariate regression analyses, adjusted for age, sex, and MMSE, to evaluate how symptoms related to the Functional Activities Questionnaire, QoL-AD questionnaire, and Zarit Caregiver Burden Interview.

RESULTS

In our cohort, RBD was the most frequently reported core feature (75%), while visual hallucinations were least frequently reported (39%) and caused minimal distress. Suggestive clinical features were commonly present, of which orthostatic hypotension was most frequently reported (64%). Ninety-five percent of patients showed EEG/MEG abnormalities, 88% of ¹²³FP-CIT SPECT scans were abnormal, and 53% had a CSF Alzheimer's disease profile. Presence of fluctuations, lower MMSE, parkinsonism, and apathy were associated with higher IADL dependency. Depression, constipation, and lower IADL were associated with lower QoL-AD. Apathy and higher IADL dependency predisposed for higher caregiver burden.

CONCLUSION

Baseline data of our prospective DLB cohort show clinically relevant associations between symptomatology and disease burden. Cognitive and motor symptoms are related to IADL functioning, while negative neuropsychiatric symptoms and functional dependency are important determinants of QoL and caregiver burden. Follow-up is currently ongoing to address specific gaps in DLB research.

Resting state EEG biomarkers of cognitive decline associated with Alzheimer's disease and mild cognitive impairment

In this paper, we explore the utility of resting-state EEG measures as potential biomarkers for the detection and assessment of cognitive decline in mild cognitive impairment (MCI) and Alzheimer's disease (AD). Neurophysiological biomarkers of AD derived from EEG and FDG-PET, once characterized and validated, would expand the set of existing diagnostic molecular biomarkers of AD pathology with associated biomarkers of disease progression and neural dysfunction. Since symptoms of AD often begin to appear later in life, successful identification of EEG-based biomarkers must account for age-related neurophysiological changes that occur even in healthy individuals. To this end, we collected EEG data from individuals with AD (n = 26), MCI (n = 53), and cognitively normal healthy controls stratified by age into three groups: 18-40 (n = 129), 40-60 (n = 62) and 60-90 (= 55) years old. For each participant, we computed power spectral density at each channel and spectral coherence between pairs of channels. Compared to age matched controls, in the AD group, we found increases in both spectral power and coherence at the slower frequencies (Delta, Theta). A smaller but significant increase in power of slow frequencies was observed for the MCI group, localized to temporal areas. These effects on slow frequency spectral power opposed that of normal aging observed by a decrease in the power of slow frequencies in our control groups. The AD group showed a significant decrease in the spectral power and coherence in the Alpha band consistent with the same effect in normal aging. However, the MCI group did not show any significant change in the Alpha band. Overall, Theta to Alpha ratio (TAR) provided the largest and most significant differences between the AD group and controls. However, differences in the MCI group remained small and localized. We proposed a novel method to quantify these small differences between Theta and Alpha bands' power using empirically derived distributions of spectral power across the time domain as opposed to averaging power across time. We defined Power Distribution Distance Measure (PDDM) as a distance measure between probability distribution functions (pdf) of Theta and Alpha power. Compared to average TAR, using PDDF enhanced the statistical significance, the effect size, and the spatial distribution of significant effects in the MCI group. We designed classifiers for differentiating individual MCI and AD participants from age-matched controls. The classification performance measured by the area under ROC curve after cross-validation were AUC = 0.85 and AUC = 0.6, for AD and MCI classifiers, respectively. Posterior probability of AD, TAR, and the proposed PDDM measure were all significantly correlated with MMSE score and neuropsychological tests in the AD group.

Altered structural connectivity networks in dementia with lewy bodies

The impairment of large-scale brain networks has been observed in dementia with Lewy bodies (DLB) using functional connectivity, but the potential for an analogous effect on structural covariance patterns has not been determined. Twenty-four probable DLB subjects (mean age 74.3 ± 6.7 years, 16.7% female) and 23 similarly aged Controls were included. All participants underwent 3T MRI imaging with high-resolution T1-weighted magnetization-prepared rapid gradient echo (MPRAGE) sequence. Graph theoretical analyses were performed using variation in regional cortical thickness to construct a structural association matrix with pairwise Pearson correlations. Global and nodal graph parameters were computed to assess between-group differences and community structure was studied in order to quantify large-scale brain networks in both groups. In comparison to Controls, DLB subjects had decreased global efficiency, clustering, modularity and small-worldness of structural networks (all p < 0.05). Nodal measures showed that DLB subjects also had decreased clustering in bilateral temporal regions and decreased closeness centrality in extensive areas including right middle frontal, left cingulate and bilateral occipital lobe (all false-discovery rate (FDR)-corrected q < 0.05). Whereas four distinct modules could be clearly identified in Controls, DLB showed extensively disorganized modules, including default-mode network and dorsal attentional network. Our results suggest a marked impairment in large-scale brain structural networks in DLB, mirroring functional connectivity networks disruption.

Evaluating a novel behavioral paradigm for visual hallucinations in Dementia with Lewy bodies

The aim of this study was to evaluate the utility of the Bistable Percept Paradigm (BPP), a computerised behavioural task that has previously been utilised for the assessment of visual hallucinations in Parkinson's Disease, in a Dementia with Lewy bodies (DLB) cohort. Dementia with Lewy bodies patients demonstrated poorer performance than healthy controls (HC) on the BPP with significantly more misperceptions and a greater failure to detect bistable percepts correctly compared to HC. Further, the number of misperceptions was also correlated with the severity of hallucinations. The findings from this study demonstrate that the BPP is a viable tool to measure misperceptions in DLB patients.

A Prodromal Brain-Clinical Pattern of Cognition in Synucleinopathies

OBJECTIVE

Isolated (or idiopathic) rapid eye movement sleep behavior disorder (iRBD) is associated with dementia with Lewy bodies (DLB) and Parkinson's disease (PD). Biomarkers are lacking to predict conversion to a dementia or a motor-first phenotype. Here, we aimed at identifying a brain-clinical signature that predicts dementia in iRBD.

METHODS

A brain-clinical signature was identified in 48 patients with polysomnography-confirmed iRBD using partial least squares between brain deformation and 27 clinical variables. The resulting variable was applied to 78 patients with iRBD followed longitudinally to predict conversion to a synucleinopathy, specifically DLB. The deformation scores from patients with iRBD were compared with 207 patients with PD, DLB, or prodromal DLB to assess if scores were higher in DLB compared to PD.

RESULTS

One latent variable explained 31% of the brain-clinical covariance in iRBD, combining cortical and subcortical deformation and subarachnoid/ventricular expansion to cognitive and motor variables. The deformation score of this signature predicted conversion to a synucleinopathy in iRBD (p = 0.036, odds ratio [OR] = 2.249; 95% confidence interval [CI] = 1.053-4.803), specifically to DLB (OR = 4.754; 95% CI = 1.283-17.618, p = 0.020) and not PD (p = 0.286). Patients with iRBD who developed dementia had scores similar to clinical and prodromal patients with DLB but higher scores compared with patients with PD. The deformation score also predicted cognitive performance over 1, 2, and 4 years in patients with PD.

INTERPRETATION

We identified a brain-clinical signature that predicts conversion in iRBD to more severe/dementing forms of synucleinopathy. This pattern may serve as a new biomarker to optimize patient care, target risk reduction strategies, and administer neuroprotective trials. ANN NEUROL 2021;89:341-357.

Tau PET and relative cerebral blood flow in dementia with Lewy bodies: A PET study

PURPOSE

Alpha-synuclein often co-occurs with Alzheimer's disease (AD) pathology in Dementia with Lewy Bodies (DLB). From a dynamic [18F]flortaucipir PET scan we derived measures of both tau binding and relative cerebral blood flow (rCBF). We tested whether regional tau binding or rCBF differed between DLB patients and AD patients and controls and examined their association with clinical characteristics of DLB.

METHODS

Eighteen patients with probable DLB, 65 AD patients and 50 controls underwent a dynamic 130-minute [18F]flortaucipir PET scan. DLB patients with positive biomarkers for AD based on cerebrospinal fluid or amyloid PET were considered as DLB with AD pathology (DLB-AD+). Receptor parametric mapping (cerebellar gray matter reference region) was used to extract regional binding potential (BPND) and R1, reflecting (AD-specific) tau pathology and rCBF, respectively. First, we performed regional comparisons of [18F]flortaucipir BPND and R1 between diagnostic groups. In DLB patients only, we performed regression analyses between regional [18F]flortaucipir BPND, R1 and performance on ten neuropsychological tests.

RESULTS

Regional [18F]flortaucipir BPND in DLB was comparable with tau binding in controls (p > 0.05). Subtle higher tau binding was observed in DLB-AD+ compared to DLB-AD- in the medial temporal and parietal lobe (both p < 0.05). Occipital and lateral parietal R1 was lower in DLB compared to AD and controls (all p < 0.01). Lower frontal R1 was associated with impaired performance on digit span forward (standardized beta, stβ = 0.72) and category fluency (stβ = 0.69) tests. Lower parietal R1 was related to lower delayed (stβ = 0.50) and immediate (stβ = 0.48) recall, VOSP number location (stβ = 0.70) and fragmented letters (stβ = 0.59) scores. Lower occipital R1 was associated to worse performance on VOSP fragmented letters (stβ = 0.61), all p < 0.05.

CONCLUSION

The amount of tau binding in DLB was minimal and did not differ from controls. However, there were DLB-specific occipital and lateral parietal relative cerebral blood flow reductions compared to both controls and AD patients. Regional rCBF, but not tau binding, was related to cognitive impairment. This indicates that assessment of rCBF may give more insight into disease mechanisms in DLB than tau PET.

[Fluctuation of cognitive functions in dementia with Lewy bodies]

Fluctuations of cognitive function (FCF) is one of the core diagnostic features of dementia with Lewy bodies (DLB). However, identification, pathophysiology, management of this unusual phenomena remain poor understood. The review presents modern ideas about phenomenology, causes, systematization, clinical significance and current methods of diagnosis and treatment of FCF in patients with DLB.

Nucleus Basalis of Meynert Stimulation for Lewy Body Dementia: A Phase I Randomized Clinical Trial

OBJECTIVES

Nucleus basalis of Meynert deep brain stimulation (NBM-DBS) has been proposed for patients with dementia. Here, we aim to assess the safety and effects of NBM-DBS in patients with Lewy body dementia (LBD), in a randomized, double-blind, crossover clinical trial.

METHODS

Six patients with mild to moderate LBD (mean [SD] age, 62.2 [7.8] years) were included, operated on for bilateral NBM-DBS, and assigned to receive either active or sham NBM-DBS followed by the opposite condition for 3 months. The primary outcome was the difference in the total free recalls of the Free and Cued Selective Reminding Test (FCSRT) between active and sham NBM-DBS. Secondary outcomes were assessments of the safety and effects of NBM-DBS on cognition, motor disability, sleep, and PET imaging.

RESULTS

There was no significant difference in the FCSRT score with active vs sham NBM-DBS. The surgical procedures were well tolerated in all patients, but we observed significant decreases in Stroop and Benton scores after electrode implantation. We observed no significant difference in other scales between active and sham NBM-DBS. With active NBM-DBS relative to baseline, phonemic fluency and motor disability significantly decreased. Lastly, the superior lingual gyrus metabolic activity significantly increased with active NBM-DBS.

CONCLUSIONS

NBM-DBS does not appear to be totally safe for patients with LBD with no evidence of cognitive benefit.

CLINICALTRIALSGOV IDENTIFIER

NCT01340001.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that, for patients with LBD operated on for bilateral NBM-DBS, active NBM-DBS stimulation compared to sham stimulation did not significantly change selective recall scores.

Abnormalities of resting-state EEG in patients with prodromal and overt dementia with Lewy bodies: Relation to clinical symptoms

OBJECTIVE

Here we tested if cortical sources of resting state electroencephalographic (rsEEG) rhythms may differ in sub-groups of patients with prodromal and overt dementia with Lewy bodies (DLB) as a function of relevant clinical symptoms.

METHODS

We extracted clinical, demographic and rsEEG datasets in matched DLB patients (N = 60) and control Alzheimer's disease (AD, N = 60) and healthy elderly (Nold, N = 60) seniors from our international database. The eLORETA freeware was used to estimate cortical rsEEG sources.

RESULTS

As compared to the Nold group, the DLB and AD groups generally exhibited greater spatially distributed delta source activities (DLB > AD) and lower alpha source activities posteriorly (AD > DLB). As compared to the DLB "controls", the DLB patients with (1) rapid eye movement (REM) sleep behavior disorders showed lower central alpha source activities (p < 0.005); (2) greater cognitive deficits exhibited higher parietal and central theta source activities as well as higher central, parietal, and occipital alpha source activities (p < 0.01); (3) visual hallucinations pointed to greater parietal delta source activities (p < 0.005).

CONCLUSIONS

Relevant clinical features were associated with abnormalities in spatial and frequency features of rsEEG source activities in DLB patients.

SIGNIFICANCE

Those features may be used as neurophysiological surrogate endpoints of clinical symptoms in DLB patients in future cross-validation prospective studies.

Evaluating the Sustained Attention Response Task to Quantify Cognitive Fluctuations in Dementia With Lewy Bodies

Cognitive fluctuations (CFs) are a core diagnostic feature of dementia with Lewy bodies (DLB). Detection of CF is still mostly based on subjective reports from the patient or informant; more quantitative measures are likely to improve the accuracy for the diagnosis of DLB. The purpose of the current study is to test whether performance on the Sustained Attention Response Task (SART) could distinguish those patients with DLB with and without CF. Twenty-four patients with DLB were tested on the SART and performance was related to scores on the Clinical Assessment of Fluctuations (CAFs) and One Day Fluctuation Assessment Scale (ODFAS). The number of "misses" made was a significant predictor of their fluctuation severity, attentional performance, disorganized thinking, and language production ratings on the ODFAS. However, measures on the SART did not correlate with measures on the CAF scale. In conclusion, these findings suggest that SART is a feasible measure of sustained attention in this population and has clinical and diagnostic relevance to the measurement of CF, particularly those aspects measured by the ODFAS.

Parkinson disease clinical subtypes: key features & clinical milestones

OBJECTIVES

Based on multi-domain classification of Parkinson disease (PD) subtypes, we sought to determine the key features that best differentiate subtypes and the utility of PD subtypes to predict clinical milestones.

METHODS

Prospective cohort of 162 PD participants with ongoing, longitudinal follow-up. Latent class analysis (LCA) delineated subtypes based on score patterns across baseline motor, cognitive, and psychiatric measures. Discriminant analyses identified key features that distinguish subtypes at baseline. Cox regression models tested PD subtype differences in longitudinal conversion to clinical milestones, including deep brain stimulation (DBS), dementia, and mortality.

RESULTS

LCA identified distinct subtypes: "motor only" (N = 63) characterized by primary motor deficits; "psychiatric & motor" (N = 17) characterized by prominent psychiatric symptoms and moderate motor deficits; "cognitive & motor" (N = 82) characterized by impaired cognition and moderate motor deficits. Depression, executive function, and apathy best discriminated subtypes. Since enrollment, 22 had DBS, 48 developed dementia, and 46 have died. Although there were no subtype differences in rate of DBS, dementia occurred at a higher rate in the "cognitive & motor" subtype. Surprisingly, mortality risk was similarly elevated for both "cognitive & motor" and "psychiatric & motor" subtypes compared to the "motor only" subtype (relative risk = 3.15, 2.60).

INTERPRETATION

Psychiatric and cognitive features, rather than motor deficits, distinguish clinical PD subtypes and predict greater risk of subsequent dementia and mortality. These results emphasize the value of multi-domain assessments to better characterize clinical variability in PD. Further, differences in dementia and mortality rates demonstrate the prognostic utility of PD subtypes.

Cholinergic muscarinic M1/M4 receptor networks in dementia with Lewy bodies

Cholinergic dysfunction is central in dementia with Lewy bodies, possibly contributing to the cognitive and psychiatric phenotypes of this condition. We investigated baseline muscarinic M₁/M₄ receptor spatial covariance patterns in dementia with Lewy bodies and their association with changes in cognition and neuropsychiatric symptoms after 12 weeks of treatment with the cholinesterase inhibitor donepezil. Thirty-eight participants (14 cholinesterase inhibitor naive patients, 24 healthy older individuals) underwent ¹²³I-iodo-quinuclidinyl-benzilate (M₁/M₄ receptor assessment) and ^99mTc-exametazime (perfusion) single-photon emission computed tomography scanning. We implemented voxel principal components analysis, producing a series of images representing patterns of inter-correlated voxels across individuals. Linear regression analyses derived specific M₁/M₄ and perfusion spatial covariance patterns associated with patients. A discreet M₁/M₄ pattern that distinguished patients from controls (W_1,19.7 = 16.7, P = 0.001), showed relative decreased binding in right lateral temporal and insula, as well as relative preserved/increased binding in frontal, precuneus, lingual and cuneal regions, implicating nodes within attention and dorsal visual networks. We then derived from patients an M₁/M₄ pattern that correlated with a positive change in mini-mental state examination (r = 0.52, P = 0.05), showing relative preserved/increased uptake in prefrontal, temporal pole and anterior cingulate, elements of attention-related networks. We also generated from patients an M₁/M₄ pattern that correlated with a positive change in neuropsychiatric inventory score (r = 0.77, P = 0.002), revealing relative preserved/increased uptake within a bilateral temporal-precuneal-striatal system. Although in a small sample and therefore tentative, we posit that optimal response of donepezil on cognitive and neuropsychiatric signs in patients with dementia with Lewy bodies were associated with a maintenance of muscarinic M₁/M₄ receptor expression within attentional/executive and ventral visual network hubs, respectively.

Cortical thinning in dementia with Lewy bodies and Parkinson disease dementia

BACKGROUND

We investigated the structural changes associated with Alzheimer's disease, dementia with Lewy bodies and Parkinson disease dementia by means of cortical thickness analysis.

METHODS

Two hundred and forty-five participants: 76 Alzheimer's disease, 65 dementia with Lewy bodies, 29 Parkinson disease dementia and 76 cognitively normal controls underwent 3-T T1-weighted magnetic resonance imaging and clinical and cognitive assessments. We implemented FreeSurfer to obtain cortical thickness estimates to contrast patterns of cortical thinning across groups and their clinical correlates.

RESULTS

In Alzheimer's disease and dementia with Lewy bodies, a largely similar pattern of regional cortical thinning was observed relative to controls apart from a more severe loss within the entorhinal and parahippocampal structures in Alzheimer's disease. In Parkinson disease dementia, regional cortical thickness was indistinguishable from controls and dementia with Lewy bodies, suggesting an 'intermediate' pattern of regional cortical change. In terms of global cortical thickness, group profiles were controls > Parkinson disease dementia > dementia with Lewy bodies > Alzheimer's disease (F_{3, 241} ⩽ 123.2, p < 0.001), where percentage wise, the average difference compared to controls were -1.8%, -5.5% and -6.4%, respectively. In these samples, cortical thinning was also associated with cognitive decline in dementia with Lewy bodies but not in Parkinson disease dementia and Alzheimer's disease.

CONCLUSION

In a large and well-characterised cohort of people with dementia, regional cortical thinning in dementia with Lewy bodies was broadly similar to Alzheimer's disease. There was preservation of the medial temporal lobe structures in dementia with Lewy bodies compared with Alzheimer's disease, supporting its inclusion as a supportive biomarker in the revised clinical criteria for dementia with Lewy bodies. However, there was less global cortical thinning in Parkinson disease dementia, with no significant regional difference between Parkinson disease dementia and controls. These findings highlight the overlap across the Alzheimer's disease/Parkinson disease dementia spectrum and the potential for differing mechanisms underlying neurodegeneration and cognition in dementia with Lewy bodies and Parkinson disease dementia.

Fluctuating cognition in the Lewy body dementias

Fluctuating cognition is a core diagnostic feature of dementia with Lewy bodies and is also a key clinical feature of Parkinson's disease dementia. These dementias share common pathological features and are referred to as Lewy body dementias. Whilst highly prevalent in Lewy body dementia, with up to 90% of patients experiencing the symptom at some point in the disease trajectory, clinical identification of fluctuating cognition is often challenging. Furthermore, its underlying pathophysiological processes remain unclear. However, neuroimaging and neurophysiological techniques have recently provided insight into potential drivers of the phenomenon. In this update, we review data pertaining to clinical features and underlying mechanisms of fluctuating cognition in Lewy body dementia. We collate evidence for different proposed aetiologies: fluctuating cognition as an attentional disorder, as a consequence of loss of cholinergic drive, as a manifestation of failure in neuronal efficiency and synchrony, and as a disorder of sleep/arousal. We also review data relating to putative mechanisms that have received less attention to date. Increased understanding of fluctuating cognition may help to illuminate pathophysiological mechanisms in cognitive processing in Lewy body dementia, guide future research, and facilitate the design of targeted therapeutic approaches.