Cognitive impairments associated with medial temporal atrophy and white matter hyperintensities: an MRI study in memory clinic patients

Association of small vessel disease progression with longitudinal cognitive decline across mild cognitive impairment

BACKGROUND

Cerebral small vessel disease (SVD) is the leading cause of vascular dementia. However, it is unclear whether the individual SVD or global SVD progression correlates with cognitive decline across mild cognitive impairment (MCI) subjects.

OBJECTIVE

To investigate the association of small vessel disease progression with longitudinal cognitive decline across MCI.

METHODS

We included 432 participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database, with 151 participants in the cognitively normal (CN) group and 281 participants in the MCI group. We evaluated magnetic resonance imaging-based SVD markers in both CN and MCI groups and explored their associations with 12-and 24-month cognitive decline using linear mixing effect (LME) models.

RESULTS

In the CN group, cerebral microbleed (CMB) progression was associated with the decline in language function (p < 0.05), and deep white matter hyperintensity (WMH) progression was associated with a decline in memory function (p < 0.05). In the MCI group, CMB progression was associated with a decline in memory function (p < 0.05) and lacunes progression was associated with executive function (p < 0.05), whereas the progression of global SVD score was not related to longitudinal cognitive function.

CONCLUSIONS

The progression of CMB and WMH had an impact on cognitive decline in both CN and MCI groups, and lacunes progression only had an association with cognitive decline in the MCI group. Our study suggested that individual SVD markers may have a higher predictive value in longitudinal cognition compared with global SVD burden.

Neuroanatomical Correlates of Cognitive Dysfunction in 22q11.2 Deletion Syndrome

22q11.2 Deletion Syndrome (22q11.2DS), the most common chromosomal microdeletion, presents as a heterogeneous phenotype characterized by an array of anatomical, behavioral, and cognitive abnormalities. Individuals with 22q11.2DS exhibit extensive cognitive deficits, both in overall intellectual capacity and focal challenges in executive functioning, attentional control, perceptual abilities, motor skills, verbal processing, as well as socioemotional operations. Heterogeneity is an intrinsic factor of the deletion's clinical manifestation in these cognitive domains. Structural imaging has identified significant changes in volume, thickness, and surface area. These alterations are closely linked and display region-specific variations with an overall increase in abnormalities following a rostral-caudal gradient. Despite the extensive literature developing around the neurocognitive and neuroanatomical profiles associated with 22q11.2DS, comparatively little research has addressed specific structure-function relationships between aberrant morphological features and deficient cognitive processes. The current review attempts to categorize these limited findings alongside comparisons to populations with phenotypic and structural similarities in order to answer to what degree structural findings can explain the characteristic neurocognitive deficits seen in individuals with 22q11.2DS. In integrating findings from structural neuroimaging and cognitive assessments, this review seeks to characterize structural changes associated with the broad neurocognitive challenges faced by individuals with 22q11.2DS.

The impact of medial temporal and parietal atrophy on cognitive function in dementia

Although medial temporal atrophy (MTA) and parietal atrophy (Koedam score) have been used to diagnose Alzheimer's disease (AD), early detection of other dementia types remains elusive. The study aims to investigate the association between these brain imaging markers and cognitive function in dementia. This cross-sectional study collected data from the Memory Clinic of Dr. Sardjito General Hospital Yogyakarta, Indonesia from January 2020 until December 2022. The cut-off value of MTA and Koedam score was set with Receiver Operating Curve. Multivariate analysis was performed to investigate the association between MTA and Koedam score with cognitive function. Of 61 patients, 22.95% had probable AD, 59.01% vascular dementia, and 18.03% mixed dementia. Correlation test showed that MTA and Koedam score were negatively associated with Montreal Cognitive Assessment-Indonesian Version (MoCA-INA) score. MTA score ≥ 3 (AUC 0.69) and Koedam score ≥ 2 (AUC 0.67) were independently associated with higher risk of poor cognitive function (OR 13.54, 95% CI 1.77-103.43, p = 0.01 and OR 5.52, 95% CI 1.08-28.19, p = 0.04). Higher MTA and Koedam score indicate worse cognitive function in dementia. Future study is needed to delineate these findings as prognostic markers of dementia severity.

Diagnostic Efficacy of Voxel-Mirrored Homotopic Connectivity in Vascular Dementia as Compared to Alzheimer's Related Neurodegenerative Diseases-A Resting State fMRI Study

Previous studies have demonstrated that functional connectivity (FC) of different brain regions in resting state function MRI were abnormal in patients suffering from mild cognitive impairment (MCI) and Alzheimer’s disease (AD) when comparing to healthy controls (HC) using seed based, independent component analysis (ICA) or small world network techniques. A new technique called voxel-mirrored homotopic connectivity (VMHC) was used in the current study to evaluate the value of interhemispheric functional connectivity (IFC) as a diagnostic tool to differentiate vascular dementia (VD) from other Alzheimer’s related neurodegenerative diseases. Eighty-three participants were recruited from the university hospital memory clinic. A multidisciplinary panel formed by a neuroradiologist and two geriatricians classified the participants into VD (13), AD (16), MCI (29), and HC (25) based on clinical history, Montreal Cognitive Assessment Hong Kong version (HK-MoCA) neuropsychological score, structural MRI, MR perfusion, and 18-F Flutametamol (amyloid) PET-CT findings of individual subjects. We adopted the calculation method used by Kelly et al. (2011) and Zuo et al. (2010) in obtaining VMHC maps. Specific patterns of VMHC maps were obtained for VD, AD, and MCI to HC comparison. VD showed significant reduction in VMHC in frontal orbital gyrus and gyrus rectus. Increased VMHC was observed in default mode network (DMN), executive control network (ECN), and the remaining salient network (SN) regions. AD showed a reduction of IFC in all DMN, ECN, and SN regions; whereas MCI showed VMHC reduction in vSN, and increased VMHC in DMN and ECN. When combining VMHC values of relevant brain regions, the accuracy was improved to 87%, 92%, and 83% for VD, AD, and MCI from HC, respectively, in receiver operating characteristic (ROC) analysis. Through studying the VMHC maps and using VMHC values in relevant brain regions, VMHC can be considered as a reliable diagnostic tool for VD, AD, and MCI from HC.

Positive Effects of Education on Cognitive Functioning Depend on Clinical Status and Neuropathological Severity

Background: Variability in cognitive functions in healthy and pathological aging is often explained by educational attainment. However, it remains unclear to which extent different disease states alter protective effects of education. We aimed to investigate whether protective effects of education on cognition depend on (1) clinical diagnosis severity, and (2) the neuropathological burden within a diagnosis in a memory clinic setting. Methods: In this cross-sectional study, we included 108 patients with subjective cognitive decline [SCD, median age 71, IQR (66-78), 43% men], 190 with mild cognitive impairment [MCI, median age 78, IQR (73-82), 44% men], and 245 with Alzheimer's disease dementia (AD) [median age 80, IQR (76-84), 35% men]. We combined visual ratings of hippocampal atrophy, global atrophy, and white matter hyperintensities on MRI into a single neuropathology score. To investigate whether the contribution of education to cognitive performance differed across SCD, MCI, and AD, we employed several multiple linear regression models, stratified by diagnosis and adjusted for age, sex, and neurodegeneration. We re-ran each model with an additional interaction term to investigate whether these effects were influenced by neuropathological burden for each diagnostic group separately. False discovery rate (FDR) corrections for multiple comparisons were applied. Results: We observed significant positive associations between education and performance for global cognition and executive functions (all adjusted p-values < 0.05). As diagnosis became more severe, however, the strength of these associations decreased (all adjusted p-values < 0.05). Education related to episodic memory only at relatively lower levels of neuropathology in SCD (β = -0.23, uncorrected p = 0.02), whereas education related to episodic memory in those with higher levels of neuropathology in MCI (β = 0.15, uncorrected p = 0.04). However, these interaction effects did not survive FDR-corrections. Conclusions: Altogether, our results demonstrated that positive effects of education on cognitive functioning reduce with diagnosis severity, but the role of neuropathological burden within a particular diagnosis was small and warrants further investigation. Future studies may further unravel the extent to which different dimensions of an individual's disease severity contribute to the waxing and waning of protective effects in cognitive aging.

Association between Self-Reported Pain, Cognition, and Neuropathology in Older Adults Admitted to an Outpatient Memory Clinic-A Cross-Sectional Study

Cognitive impairment has been linked to reduced self-reporting of pain. However, it is unclear whether the various cognitive functions are similarly and/or independently associated with such pain report measures. In the present study, we explored how executive functioning (EF), memory, and global cognition relate to self-reported pain and investigated whether underlying neuropathology partially accounts for these results. We used Lasso categorical regression to analyze data from 179 individuals visiting a memory clinic. The data included the self-reported pain occurrence, intensity, severity and frequency, clinical diagnoses, neuropsychological scores, white matter hyperintensities, medial temporal lobe atrophy, depressive symptoms, and demographics. Our results showed that worse memory and EF performance predicted a lower pain occurrence. In those individuals who did report pain, worse memory predicted lower pain intensity, severity, and frequency levels, but for EF reversed effects were found, with worse EF predicting higher pain scores. These relationships were only partially explained by reductions in white matter and medial temporal lobe integrity. Similar effects were found for depressive symptoms. Our findings highlight the distinct associations of EF and memory with self-reported pain. A similar pattern of relationships found for both self-reported pain and depressive symptoms may reflect shared latent affective components.

Progressive Brain Degeneration From Subjective Cognitive Decline to Amnestic Mild Cognitive Impairment: Evidence From Large-Scale Anatomical Connection Classification Analysis

People with subjective cognitive decline (SCD) and amnestic mild cognitive impairment (aMCI) are both at high risk for Alzheimer’s disease (AD). Behaviorally, both SCD and aMCI have subjective reports of cognitive decline, but the latter suffers a more severe objective cognitive impairment than the former. However, it remains unclear how the brain develops from SCD to aMCI. In the current study, we aimed to investigate the topological characteristics of the white matter (WM) network that can successfully identify individuals with SCD or aMCI from healthy control (HC) and to describe the relationship of pathological changes between these two stages. To this end, three groups were recruited, including 22 SCD, 22 aMCI, and 22 healthy control (HC) subjects. We constructed WM network for each subject and compared large-scale topological organization between groups at both network and nodal levels. At the network level, the combined network indexes had the best performance in discriminating aMCI from HC. However, no indexes at the network level can significantly identify SCD from HC. These results suggested that aMCI but not SCD was associated with anatomical impairments at the network level. At the nodal level, we found that the short-path length can best differentiate between aMCI and HC subjects, whereas the global efficiency has the best performance in differentiating between SCD and HC subjects, suggesting that both SCD and aMCI had significant functional integration alteration compared to HC subjects. These results converged on the idea that the neural degeneration from SCD to aMCI follows a gradual process, from abnormalities at the nodal level to those at both nodal and network levels.

Sarcopenia is independently associated with parietal atrophy in older adults

INTRODUCTION

As populations age, sarcopenia becomes a major health problem among adults aged 65 years and older. However, little information is available about the relationship between sarcopenia and brain structure abnormalities. The objective of this study was to investigate associations between sarcopenia and brain atrophy in older adults and relationships with regional brain areas.

METHODS

This prospective cohort study recruited 102 retirement community residents aged 65 years and older. All participants underwent gait speed measurement, handgrip strength measurement and muscle mass measurement by dual X-ray absorptiometry. Diagnosis of sarcopenia was made according to criteria of the Asian Working Group for Sarcopenia (AWGSOP). All patients underwent magnetic resonance imaging (MRI), and images were analysed for global cortical atrophy (GCA) (range 0-3), parietal atrophy (PA) (range 0-3) and medial temporal atrophy (MTA) (range 0-4).

RESULTS

Among 102 older adult participants (81.4 ± 8.2 years), 47 (46.1%) were diagnosed with sarcopenia according to AWGSOP criteria. The sarcopenia group had more moderate to severe PA (Grade 2: 19.1% vs. 5.5%; grade 3:6.4% vs. 0%, P = 0.016) and GCA (Grade 2: 40.4% vs. 18.2%, P = 0.003) and a trend of more moderate to severe MTA (Grade 2: 46.8% vs. 30.9%; grade 3: 8.5% vs. 1.8%, P = 0.098) than the non-sarcopenia group. In univariate logistic regression, sarcopenia was significantly associated with PA (OR 5.94, 95% CI 1.56-22.60, P = 0.009), GCA (OR 3.05, 95% CI 1.24-7.51, P = 0.015), and MTA (OR 2.55, 95% CI 1.14-5.69, P = 0.023). In multivariable logistic regression analysis, sarcopenia was an independent risk factor for PA (adjusted OR 6.90, 95% CI 1.30-36.47, P = 0.023). After adjusting for all covariates, only age had a significant relationship with GCA (Adjusted OR 1.09, 95% CI 1.00-1.19, P = 0.044) and MTA (Adjusted OR 1.09, 95% CI 1.01-1.17, P = 0.022).

CONCLUSIONS

This is the first study to explore associations between sarcopenia and global as well as regional brain atrophy in older adults. The sarcopenia group had higher rates of moderate to severe PA, GCA and MTA than the non-sarcopenia group. PA was significantly associated with sarcopenia in older adults. Further longitudinal studies are needed to address the mechanism and pathogenesis of brain atrophy and sarcopenia.

Periventricular and deep abnormal white matter differ in associations with cognitive performance at midlife

Objective: Abnormal white matter (AWM) on magnetic resonance imaging is associated with cognitive performance in older adults. We explored cognitive associations with AWM during late-midlife. Method: Participants were community-dwelling men (n = 242; M = 61.90 years; range = 56-66). Linear-mixed effects regression models examined associations of total, periventricular, and deep AWM with cognitive performance, controlling for multiple comparisons. Models considering specific cognitive domains controlled for current general cognitive ability (GCA). We hypothesized that total AWM would be associated with worse processing speed, executive function, and current GCA; deep AWM would correlate with GCA and periventricular AWM would relate to specific cognitive abilities. We also assessed the potential influence of cognitive reserve by examining a moderation effect of early life (mean age of 20) cognition. Results: Greater total and deep AWM were associated with poorer current GCA. Periventricular AWM was associated with worse executive function, working memory, and episodic memory. When periventricular and deep AWM were modeled simultaneously, both retained their respective significant associations with cognitive performance. Cognitive reserve did not moderate associations. Conclusions: Our findings suggest that AWM contributes to poorer cognitive function in late-midlife. Examining only total AWM may obscure the potential differential impact of regional AWM. Separating total AWM into subtypes while controlling for current GCA revealed a dissociation in relationships with cognitive performance; deep AWM was associated with nonspecific cognitive ability whereas periventricular AWM was associated with specific frontal-related abilities and memory. Management of vascular or other risk factors that may increase the risk of AWM should begin during or before early late-midlife. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Altered Granger Causal Connectivity of Resting-State Neural Networks in Patients With Leukoaraiosis-Associated Cognitive Impairment-A Cross-Sectional Study

Background: The purpose of this study was to provide an imaging reference for the measurement of disease progression, as well as to reveal the pathogenesis of leukoaraiosis (LA).

Methods: Eighty-seven subjects were divided into three groups: LA patients with vascular dementia (LA-VaD) (20 subjects: 14 female, 6 male), LA patients with vascular cognitive impairment nondementia (LA-VCIND) (32 subjects: 14 male, 18 female), and normal controls (NC) (35 subjects: 14 male, 21 female). A multivariate Granger causality analysis (mGCA) was applied to the resting-state networks (RSNs) to evaluate the possible effective connectivity within the resting-state networks retrieved by independent component analysis (ICA) from resting-state functional magnetic resonance imaging (rs-fMRI) data.

Results: Ten RSNs were identified: the primary visual network, secondary visual network, auditory network, sensorimotor network, anterior default mode network, posterior default mode network, salience network, dorsal attention network, left working memory network, and the right working memory network. Using independent component analysis, significant average Z scores were found in the anterior default mode network, salience network, dorsal attention network, and right working memory network between LA-VAD and NC groups. The functional connectivity (FC) strength of the networks was different between the NC, LA-VCIND, and LA-VaD groups. Effective connectivity between RSNs was compensated by either increased or decreased effective connectivity changes in these three groups.

Conclusions: The components of resting-state networks kept changing as the disease progressed. Meanwhile, the activation intensity increased at the early stage of LA and decreased as patients' cognitive impairment aggravated. Furthermore, the direction and strength of connections between these networks changed and remodeled differently. These suggest that the human brain compensates for specific functional changes at different stages.

Structural magnetic resonance imaging for the early diagnosis of dementia due to Alzheimer's disease in people with mild cognitive impairment

BACKGROUND

Mild cognitive impairment (MCI) due to Alzheimer's disease is the symptomatic predementia phase of Alzheimer's disease dementia, characterised by cognitive and functional impairment not severe enough to fulfil the criteria for dementia. In clinical samples, people with amnestic MCI are at high risk of developing Alzheimer's disease dementia, with annual rates of progression from MCI to Alzheimer's disease estimated at approximately 10% to 15% compared with the base incidence rates of Alzheimer's disease dementia of 1% to 2% per year.

OBJECTIVES

To assess the diagnostic accuracy of structural magnetic resonance imaging (MRI) for the early diagnosis of dementia due to Alzheimer's disease in people with MCI versus the clinical follow-up diagnosis of Alzheimer's disease dementia as a reference standard (delayed verification). To investigate sources of heterogeneity in accuracy, such as the use of qualitative visual assessment or quantitative volumetric measurements, including manual or automatic (MRI) techniques, or the length of follow-up, and age of participants. MRI was evaluated as an add-on test in addition to clinical diagnosis of MCI to improve early diagnosis of dementia due to Alzheimer's disease in people with MCI.

SEARCH METHODS

On 29 January 2019 we searched Cochrane Dementia and Cognitive Improvement's Specialised Register and the databases, MEDLINE, Embase, BIOSIS Previews, Science Citation Index, PsycINFO, and LILACS. We also searched the reference lists of all eligible studies identified by the electronic searches.

SELECTION CRITERIA

We considered cohort studies of any size that included prospectively recruited people of any age with a diagnosis of MCI. We included studies that compared the diagnostic test accuracy of baseline structural MRI versus the clinical follow-up diagnosis of Alzheimer's disease dementia (delayed verification). We did not exclude studies on the basis of length of follow-up. We included studies that used either qualitative visual assessment or quantitative volumetric measurements of MRI to detect atrophy in the whole brain or in specific brain regions, such as the hippocampus, medial temporal lobe, lateral ventricles, entorhinal cortex, medial temporal gyrus, lateral temporal lobe, amygdala, and cortical grey matter.

DATA COLLECTION AND ANALYSIS

Four teams of two review authors each independently reviewed titles and abstracts of articles identified by the search strategy. Two teams of two review authors each independently assessed the selected full-text articles for eligibility, extracted data and solved disagreements by consensus. Two review authors independently assessed the quality of studies using the QUADAS-2 tool. We used the hierarchical summary receiver operating characteristic (HSROC) model to fit summary ROC curves and to obtain overall measures of relative accuracy in subgroup analyses. We also used these models to obtain pooled estimates of sensitivity and specificity when sufficient data sets were available.

MAIN RESULTS

We included 33 studies, published from 1999 to 2019, with 3935 participants of whom 1341 (34%) progressed to Alzheimer's disease dementia and 2594 (66%) did not. Of the participants who did not progress to Alzheimer's disease dementia, 2561 (99%) remained stable MCI and 33 (1%) progressed to other types of dementia. The median proportion of women was 53% and the mean age of participants ranged from 63 to 87 years (median 73 years). The mean length of clinical follow-up ranged from 1 to 7.6 years (median 2 years). Most studies were of poor methodological quality due to risk of bias for participant selection or the index test, or both. Most of the included studies reported data on the volume of the total hippocampus (pooled mean sensitivity 0.73 (95% confidence interval (CI) 0.64 to 0.80); pooled mean specificity 0.71 (95% CI 0.65 to 0.77); 22 studies, 2209 participants). This evidence was of low certainty due to risk of bias and inconsistency. Seven studies reported data on the atrophy of the medial temporal lobe (mean sensitivity 0.64 (95% CI 0.53 to 0.73); mean specificity 0.65 (95% CI 0.51 to 0.76); 1077 participants) and five studies on the volume of the lateral ventricles (mean sensitivity 0.57 (95% CI 0.49 to 0.65); mean specificity 0.64 (95% CI 0.59 to 0.70); 1077 participants). This evidence was of moderate certainty due to risk of bias. Four studies with 529 participants analysed the volume of the total entorhinal cortex and four studies with 424 participants analysed the volume of the whole brain. We did not estimate pooled sensitivity and specificity for the volume of these two regions because available data were sparse and heterogeneous. We could not statistically evaluate the volumes of the lateral temporal lobe, amygdala, medial temporal gyrus, or cortical grey matter assessed in small individual studies. We found no evidence of a difference between studies in the accuracy of the total hippocampal volume with regards to duration of follow-up or age of participants, but the manual MRI technique was superior to automatic techniques in mixed (mostly indirect) comparisons. We did not assess the relative accuracy of the volumes of different brain regions measured by MRI because only indirect comparisons were available, studies were heterogeneous, and the overall accuracy of all regions was moderate.

AUTHORS' CONCLUSIONS

The volume of hippocampus or medial temporal lobe, the most studied brain regions, showed low sensitivity and specificity and did not qualify structural MRI as a stand-alone add-on test for an early diagnosis of dementia due to Alzheimer's disease in people with MCI. This is consistent with international guidelines, which recommend imaging to exclude non-degenerative or surgical causes of cognitive impairment and not to diagnose dementia due to Alzheimer's disease. In view of the low quality of most of the included studies, the findings of this review should be interpreted with caution. Future research should not focus on a single biomarker, but rather on combinations of biomarkers to improve an early diagnosis of Alzheimer's disease dementia.

Medial Temporal Lobe Atrophy is Related to Learning Strategy Changes in Amnestic Mild Cognitive Impairment

OBJECTIVE

Deficits in the semantic learning strategy were observed in subjects with amnestic mild cognitive impairment (aMCI) in our previous study. In the present study, we explored the contributions of executive function and brain structure changes to the decline in the semantic learning strategy in aMCI.

METHODS

A neuropsychological battery was used to test memory and executive function in 96 aMCI subjects and 90 age- and gender-matched healthy controls (HCs). The semantic clustering ratio on the verbal learning test was calculated to evaluate learning strategy. Medial temporal lobe atrophy (MTA) and white matter hyperintensities (WMH) were measured on MRI with the MTA and Fazekas visual rating scales, respectively.

RESULTS

Compared to HCs, aMCI subjects had poorer performance in terms of memory, executive function, and the semantic clustering ratio (P < .001). In aMCI subjects, no significant correlation between learning strategy and executive function was observed. aMCI subjects with obvious MTA demonstrated a lower semantic clustering ratio than those without MTA (P < .001). There was no significant difference in the learning strategies between subjects with high-grade WMH and subjects with low-grade WMH.

CONCLUSION

aMCI subjects showed obvious impairment in the semantic learning strategy, which was attributable to MTA but independent of executive dysfunction and subcortical WMH. These findings need to be further validated in large cohorts with biomarkers identified using volumetric brain measurements. (JINS, 2019, 25, 706-717).

Domain-specific cognitive effects of white matter pathology in old age, mild cognitive impairment and Alzheimer's disease

Concomitant white matter (WM) brain pathology is often present in patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD). Cognitive effects of WM pathology on cognition in normal and pathological aging have been studied, but very little is known about possible group-specific effects in old age, MCI and AD. The purpose of the current study was to examine the relationship between WM pathology and cognitive functioning in four cognitive domains in old age, MCI and AD. The study utilized multi-domain neuropsychological data and visually rated MRI imaging data from a sample of 56 healthy older adults, 40 patients with MCI and 52 patients with AD (n = 148). After controlling for age and education, main effects of frontal WM pathology (especially in the left hemisphere) were found for cognitive performances in two domains, whereas a main effect of parieto-occipital WM pathology was only found for processing speed. In addition, with regard to processing speed, an interaction between group and WM changes was found: Patients with AD that had moderate or severe left frontal WM pathology were considerably slower than patients with AD that had milder cerebrovascular pathology. Frontal WM pathology, especially in the left hemisphere, seems to affect cognitive functions in many domains in all three groups. The results of the study increase our knowledge of cognitive repercussions stemming from frontal and/or parieto-occipital WM pathology in AD. Clinicians should be aware that patients with AD with prominent frontal cerebrovascular pathology can have considerably slowed cognitive processing.

Cognitive Profiles and Atrophy Ratings on MRI in Senior Patients With Mild Cognitive Impairment

In this cross-sectional study, we sought to describe cognitive and neuroimaging profiles of Memory clinic patients with Mild Cognitive Impairment (MCI). 51 MCI patients and 51 controls, matched on age, sex, and socio-economic status (SES), were assessed with an extensive neuropsychological test battery that included a measure of intelligence (General Ability Index, "GAI," from WAIS-IV), and structural magnetic resonance imaging (MRI). MCI subtypes were determined after inclusion, and z-scores normalized to our control group were generated for each cognitive domain in each MCI participant. MR-images were scored by visual rating scales. MCI patients performed significantly worse than controls on 23 of 31 cognitive measures (Bonferroni corrected p = 0.001), and on 8 of 31 measures after covarying for intelligence (GAI). Compared to nonamnestic MCI patients, amnestic MCI patients had lower test results in 13 of 31 measures, and 5 of 31 measures after co-varying for GAI. Compared to controls, the MCI patients had greater atrophy on Schelten's Medial temporal lobe atrophy score (MTA), especially in those with amnestic MCI. The only structure-function correlation that remained significant after correction for multiple comparisons was the MTA-long delay recall domain. Intelligence operationalized as GAI appears to be an important moderator of the neuropsychological outcomes. Atrophy of the medial temporal lobe, based on MTA scores, may be a sensitive biomarker for the functional episodic memory deficits associated with MCI.

Evaluation and clinical correlation of practical cut-offs for visual rating scales of atrophy: normal aging versus mild cognitive impairment and Alzheimer's disease

Age-related brain atrophy is a common finding, but neurodegenerative diseases such as Alzheimer's disease are associated with accelerated atrophy of the medial temporal lobe. In current practice for brain atrophy evaluation, several rating scales are being used such as the medial temporal atrophy (MTA), global cortical atrophy-frontal subscale (GCA-F) and posterior atrophy (PA) scales. Practical cut-offs to differentiate between normal and advanced brain atrophy are needed, because of their possible usefulness as a biomarker. A retrospective study was performed over a 1-year period resulting in a total of 79 subjects [27 patients with Alzheimer's disease (AD), 27 patients with minimal cognitive impairment (MCI) and 25 control subjects]. The MTA, GCA-F and PA scales were applied blinded and independent by two raters. Possible age- and disease-related cut-offs were computed. The MTA scale showed significantly better diagnostic performances and inter-rater agreement than the PA and GCA-F scales. We could not confirm the suggested MTA cut-off for each decade. However, an MTA score of >1 and >1.75 was considered pathological, respectively, in the population under and over 70 years. MTA can be of use in making distinction between age-related atrophy and abnormal increase of atrophy. Systematic assessment of regional brain atrophy through the use of MTA in MRI images could be a useful biomarker in aiding the early diagnosis of Alzheimer's disease.

Regional Gray Matter Volumes as Related to Psychomotor Slowing in Adults with Type 1 Diabetes

OBJECTIVE

Psychomotor slowing is a common cognitive complication in type 1 diabetes (T1D), but its neuroanatomical correlates and risk factors are unclear. In nondiabetic adults, smaller gray matter volume (GMV) and presence of white matter hyperintensities are associated with psychomotor slowing. We hypothesize that smaller GMV in prefronto-parietal regions explains T1D-related psychomotor slowing. We also inspect the contribution of microvascular disease and hyperglycemia.

METHODS

GMV, white matter hyperintensities (WMH), and glucose levels were measured concurrently with a test of psychomotor speed (Digit Symbol Substitution Test [DSST]) in 95 adults with childhood-onset T1D (mean age/duration = 49/41 years) and 135 similarly aged non-T1D adults. Linear regression models tested associations between DSST and regional GMV, controlling for T1D, sex, and education; a bootstrapping method tested whether regional GMV explained between-group differences in DSST. For the T1D cohort, voxel-based and a priori regions-of-interest methods further tested associations between GMV and DSST, adjusting for WMH, hyperglycemia, and age.

RESULTS

Bilateral putamen, but no other regions examined, significantly attenuated DSST differences between the cohorts (bootstrapped unstandardized indirect effects: -3.49, -3.26; 95% confidence interval = -5.49 to -1.80, -5.29 to -1.44, left and right putamen, respectively). Among T1D, DSST was positively associated with GMV of bilateral putamen and left thalamus. Neither WMH, hyperglycemia, age, nor other factors substantially modified these relationships.

CONCLUSIONS

For middle-aged adults with T1D and cerebral microvascular disease, GMV of basal ganglia may play a critical role in regulating psychomotor speed, as measured via DSST. Studies to quantify the impact of basal ganglia atrophy concurrent with WMH progression on psychomotor slowing are warranted.

Rule induction performance in amnestic mild cognitive impairment and Alzheimer's dementia: examining the role of simple and biconditional rule learning processes

INTRODUCTION

Rule induction tests such as the Wisconsin Card Sorting Test require executive control processes, but also the learning and memorization of simple stimulus-response rules. In this study, we examined the contribution of diminished learning and memorization of simple rules to complex rule induction test performance in patients with amnestic mild cognitive impairment (aMCI) or Alzheimer's dementia (AD).

METHOD

Twenty-six aMCI patients, 39 AD patients, and 32 control participants were included. A task was used in which the memory load and the complexity of the rules were independently manipulated. This task consisted of three conditions: a simple two-rule learning condition (Condition 1), a simple four-rule learning condition (inducing an increase in memory load, Condition 2), and a complex biconditional four-rule learning condition-inducing an increase in complexity and, hence, executive control load (Condition 3).

RESULTS

Performance of AD patients declined disproportionately when the number of simple rules that had to be memorized increased (from Condition 1 to 2). An additional increment in complexity (from Condition 2 to 3) did not, however, disproportionately affect performance of the patients. Performance of the aMCI patients did not differ from that of the control participants. In the patient group, correlation analysis showed that memory performance correlated with Condition 1 performance, whereas executive task performance correlated with Condition 2 performance.

CONCLUSIONS

These results indicate that the reduced learning and memorization of underlying task rules explains a significant part of the diminished complex rule induction performance commonly reported in AD, although results from the correlation analysis suggest involvement of executive control functions as well. Taken together, these findings suggest that care is needed when interpreting rule induction task performance in terms of executive function deficits in these patients.

Brain health: the importance of recognizing cognitive impairment: an IAGG consensus conference

Cognitive impairment creates significant challenges for patients, their families and friends, and clinicians who provide their health care. Early recognition allows for diagnosis and appropriate treatment, education, psychosocial support, and engagement in shared decision-making regarding life planning, health care, involvement in research, and financial matters. An IAGG-GARN consensus panel examined the importance of early recognition of impaired cognitive health. Their major conclusion was that case-finding by physicians and health professionals is an important step toward enhancing brain health for aging populations throughout the world. This conclusion is in keeping with the position of the United States' Centers for Medicare and Medicaid Services that reimburses for detection of cognitive impairment as part the of Medicare Annual Wellness Visit and with the international call for early detection of cognitive impairment as a patient's right. The panel agreed on the following specific findings: (1) validated screening tests are available that take 3 to 7 minutes to administer; (2) a combination of patient- and informant-based screens is the most appropriate approach for identifying early cognitive impairment; (3) early cognitive impairment may have treatable components; and (4) emerging data support a combination of medical and lifestyle interventions as a potential way to delay or reduce cognitive decline.

Medial temporal lobe atrophy is underreported and may have important clinical correlates in medical inpatients

Background

The diagnostic workup in dementia includes brain imaging with reading focussed on signs of cerebrovascular and neurodegenerative disease. We hypothesised that these findings may be underreported in hospital patients, where imaging is often performed to rule out obvious pathology such as haemorrhage. In this study, we review cranial computed tomography (CT) in medical inpatients for white matter changes and atrophy. Our aim was to determine the clinical relevance of such findings and to what extent they were underreported.

Methods

Records from 200 inpatients aged over 60 years, who had been subjected to MMSE (mini-mental state examination) and CDT (clock-drawing test), were reviewed for cranial CT. Transverse and coronal slices were reassessed using visual rating scales regarding white matter changes (WMC), global cortical atrophy (GCA) and medial temporal lobe atrophy (MTA). Findings were compared with the original radiology reports and cognitive test results.

Results

Cranial CT had been performed in 94 of 200(47 %) patients. Of these, 58(62 %) had abnormal WMC, 35(37 %) abnormal GCA and 34(36 %) abnormal MTA. All three findings had associations with cognitive test results. Abnormal MTA was associated with lower results on the overall score on MMSE and on orientation, memory and language items. All three measurements were underreported in the original radiology reports; none of the 34 patients with abnormal MTA had been reported originally.

Conclusions

Signs of neurodegenerative disease, especially MTA, were highly underreported in cranial CT scans performed in medical inpatients. At the same time, MTA seemed to hold the most important clinical correlates. Our results suggest that MTA should be reported more regularly in this setting.