Altered empathy processing in frontotemporal dementia A task-based fMRI study

A lack of empathy, and particularly its affective components, is a core symptom of behavioural variant frontotemporal dementia (bvFTD). Visual exposure to images of a needle pricking a hand (pain condition) and Q-tips touching a hand (control condition) is an established functional magnetic resonance imaging (fMRI) paradigm used to investigate empathy for pain (EFP; pain condition minus control condition). EFP has been associated with increased blood oxygen level dependent (BOLD) signal in regions known to become atrophic in the early stages in bvFTD, including the anterior insula and the anterior cingulate. We therefore hypothesized that patients with bvFTD would display altered empathy processing in the EFP paradigm. Here we examined empathy processing using the EFP paradigm in 28 patients with bvFTD and 28 sex and age matched controls. Participants underwent structural MRI, task-based and resting-state fMRI. The Interpersonal Reactivity Index (IRI) was used as a measure of different facets of empathic function outside the scanner. The EFP paradigm was analysed at a whole brain level and using two regions-of-interest approaches, one based on a metanalysis of affective perceptual empathy versus cognitive evaluative empathy and one based on the controĺs activation pattern. In controls, EFP was linked to an expected increase of BOLD signal that displayed an overlap with the pattern of atrophy in the bvFTD patients (insula and anterior cingulate). Additional regions with increased signal were the supramarginal gyrus and the occipital cortex. These latter regions were the only ones that displayed increased BOLD signal in bvFTD patients. BOLD signal increase under the affective perceptual empathy but not the cognitive evaluative empathy region of interest was significantly greater in controls than in bvFTD patients. The controĺs rating on their empathic concern subscale of the IRI was significantly correlated with the BOLD signal in the EFP paradigm, as were an informantś ratings of the patientś empathic concern subscale. This correlation was not observed on other subscales of the IRI or when using the patient's self-ratings. Finally, controls and patients showed different connectivity patterns in empathy related networks during resting-state fMRI, mainly in nodes overlapping the ventral attention network. Our results indicate that reduced neural activity in regions typically affected by pathology in bvFTD is associated with reduced empathy processing, and a predictor of patientś capacity to experience affective empathy.

Odor Identification Across Time in Mutation Carriers and Non-Carriers in Autosomal-Dominant Alzheimer's Disease

BACKGROUND

Impaired odor identification is a characteristic of sporadic Alzheimer'sdisease(AD), but its presence in autosomal-dominantAD (adAD) remains uncertain.

OBJECTIVE

To investigate odor identification ability in mutation carriers (MC) and non-carriers (NC) of adAD in relation to years to estimated clinical onset clinical onset (YECO) of disease.

METHODS

Participants from six families with autosomal-dominant mutations (APP Swedish, APP Arctic, and PSEN1 mutations) included 20 MC and 20 NC. The groups were comparable in age, gender, education, number of APOE ɛ4 alleles, and YECO, but differed in global cognition (Mini-Mental State Examination). The MC group included individuals in asymptomatic, symptomatic cognitively unimpaired, mild cognitive impairment, and dementia stages of disease, spanning approximately 40 years of the AD continuum. All NC were asymptomatic. Olfactory function was assessed by means of free and cued identification of common odors summarized as total identification.

RESULTS

MC performed poorer than NC in free and total identification. Four MC and none of the NC were anosmic. Olfactory functions in MC and NC were significantly and inversely related to time course (YECO) for both free and total identification. The decline in free identification began approximately 10 years prior to the estimated clinical onset of AD in MC. Odor identification proficiency was associated with episodic memory and executive function in MC and NC.

CONCLUSIONS

Impaired odor identification is present well before the clinical diagnosis of AD in MC and is associated with disease progression. Odor identification ability may be a useful early biomarker for adAD.

A biomarker-validated time scale in years of disease progression has identified early- and late-onset subgroups in sporadic Alzheimer's disease

BACKGROUND

It is possible to calculate the number of years to the expected clinical onset (YECO) of autosomal-dominant Alzheimer's disease (adAD). A similar time scale is lacking for sporadic Alzheimer's disease (sAD). The purpose was to design and validate a time scale in YECO for patients with sAD in relation to CSF and PET biomarkers.

METHODS

Patients diagnosed with Alzheimer's disease (AD, n = 48) or mild cognitive impairment (MCI, n = 46) participated in the study. They underwent a standardized clinical examination at the Memory clinic, Karolinska University Hospital, Stockholm, Sweden, which included present and previous medical history, laboratory screening, cognitive assessment, CSF biomarkers (Aβ₄₂, total-tau, and p-tau), and an MRI of the brain. They were also assessed with two PET tracers, ¹¹C-Pittsburgh compound B and ¹⁸F-fluorodeoxyglucose. Assuming concordance of cognitive decline in sAD and adAD, YECO for these patients was calculated using equations for the relationship between cognitive performance, YECO, and years of education in adAD (Almkvist et al. J Int Neuropsychol Soc 23:195-203, 2017).

RESULTS

The mean current point of disease progression was 3.2 years after the estimated clinical onset in patients with sAD and 3.4 years prior to the estimated clinical onset in patients with MCI, as indicated by the median YECO from five cognitive tests. The associations between YECO and biomarkers were significant, while those between chronological age and biomarkers were nonsignificant. The estimated disease onset (chronological age minus YECO) followed a bimodal distribution with frequency maxima before (early-onset) and after (late-onset) 65 years of age. The early- and late-onset subgroups differed significantly in biomarkers and cognition, but after control for YECO, this difference disappeared for all except the APOE e4 gene (more frequent in early- than in late-onset).

CONCLUSIONS

A novel time scale in years of disease progression based on cognition was designed and validated in patients with AD using CSF and PET biomarkers. Two early- and late-disease onset subgroups were identified differing with respect to APOE e4.

APOE ε4 influences cognitive decline positively in APP and negatively in PSEN1 mutation carriers with autosomal-dominant Alzheimer's disease

BACKGROUND AND PURPOSE

The aim was to investigate the effect of APOE ε4 allele on cognitive decline in adAD. Presence of the APOE ε4 allele reduces age of symptom onset, increases disease progression, and lowers cognitive performance in sporadic Alzheimer's disease (AD), while the impact of the APOE ε4 allele in autosomal-dominant AD (adAD) is incompletely known.

METHODS

Mutation carriers (MCs; n = 39) and non-carriers (NCs; n = 40) from six adAD families harbouring a mutation in the APP (28 MCs and 25 NCs) or the PSEN1 genes (11 MCs and 15 NCs) underwent repeated cognitive assessments. A timeline of disease course was defined as years to expected age of clinical onset (YECO) based on history of disease onset in each family. The MC and NC groups were comparable with regard to demographics and prevalence of the APOE ε4 allele. The relationship between cognitive decline and YECO, YECO2 , education, APOE, and APOE-by-YECO interaction was analysed using linear mixed-effects models.

RESULTS

The trajectory of cognitive decline was significantly predicted by linear and quadratic YECO and education in MCs and was determined by age and education in NCs. Adding APOE ε4 allele (presence/absence) as a predictor did not change the results in the MC and NC groups. The outcome also remained the same for MCs and NCs after adding the APOE-by-YECO interaction as a predictor. Analyses of APP and PSEN1 MCs separately showed favourable APOE-by-YECO interaction in APP (less steep decline) and unfavourable interaction in PSEN1 (steeper decline), linked to the APOE ε4 allele.

CONCLUSION

The APOE ε4 allele influences cognitive decline positively in APP and negatively in PSEN1 mutation carriers with adAD, indicating a possible antagonistic pleiotropy.

Practice effects in cognitive assessments three years later in non-carriers but not in symptom-free mutation carriers of autosomal-dominant Alzheimer's disease: Exemplifying procedural learning and memory?

Practice effects (PEs) defined as an improvement of performance in cognition due to repeated assessments between sessions are well known in unimpaired individuals, while less is known about impaired cognition and particularly in latent brain disease as autosomal-dominant Alzheimer's disease. The purpose was to evaluate the general (across tests/domains) and domain-specific PE calculated as the annual rate of change (ARC) in relation to years to the estimated disease onset (YECO) and in four groups of AD: asymptomatic mutation carriers (aAD, n = 19), prodromal, i.e., symptomatic mutation carriers, criteria for AD diagnosis not fulfilled (pAD, n = 4) and mutation carriers diagnosed with AD (dAD, n = 6) as well as mutation non-carriers from the AD families serving as a healthy comparison group (HC, n = 35). Cognition was assessed at baseline and follow-up about 3 years later by 12 tests covering six domains. The aAD and HC groups were comparable at baseline in demographic characteristics (age, gender, and education), when they were in their early forties, while the pAD and dAD groups were older and cognitively impaired. The results on mean ARC for the four groups were significantly different, small, positive, and age-insensitive in the HC group, while ARC was negative and declined with time/disease advancement in AD. The differences between HC and aAD groups in mean ARC and domain-specific ARC were not significant, indicating a subtle PE in aAD in the early preclinical stage of AD. In the symptomatic stages of AD, there was no PE probably due to cognitive disease-related progression. PEs were the largest in the verbal domain in both the HC and aAD groups, indicating a relationship with cognitive vulnerability. The group-related difference in mean ARC was predominant in timekeeping tests. To conclude, the practice effect in over 3 years was suggested to be linked to procedural learning and memory.

Processing speed and working memory are predicted by components of successful aging: a HUNT study

BACKGROUND

Research has demonstrated that cognitive heterogeneity occurs with aging both within and between individuals. The purpose of this study was to explore whether the cognitive heterogeneity in aging was related to the subgroups of successful and usual aging.

METHOD

Participants were a representative sample of normal older adults (n = 65, age range 70-89 years). All subjects had participated in the third phase of the Nord-Trøndelag Health Survey (HUNT3) and completed all subtests in the Wechsler Memory Scale (WMS-III) and Wechsler Adult Intelligence Scale (WAIS-III). Successful aging was defined in four ways in the study: as (1) absence of disease, (2) high functioning, (3) active engagement with life, or (4) all three components combined. Five domains of memory and intelligence functions were investigated using linear regression analysis, with group membership (successful versus usual aging) as predictors and age, sex and education as correlates.

RESULTS

Processing speed performance was correlated with the successful aging component absence of disease, younger age and being of the female sex, while working memory performance was correlated with the successful aging component absence of disease and more years of education. Performance in other domains (verbal, visuospatial, and episodic memory) were not related to any successful aging definition. Age had a consistent negative effect on the processing speed domain for all successful aging definitions. Education was positively linked to cognitive performance on the verbal and working memory domains. Being female was positively linked to processing speed and episodic memory.

CONCLUSIONS

Processing speed and working memory were linked to successful aging when it was defined as absence of disease, but not by other components of successful aging, i.e. domain-specific. In contrast, other cognitive domains were not related to any components of successful aging.

The APOE ε4 Allele Affects Cognitive Functions Differently in Carriers of APP Mutations Compared to Carriers of PSEN1 Mutations in Autosomal-Dominant Alzheimer's Disease

Mounting evidence shows that the APOE ε4 allele interferes with cognition in sporadic Alzheimer’s disease. Less is known about APOE in autosomal-dominant Alzheimer’s disease (adAD). The present study explored the effects on cognition associated with the gene–gene interactions between the APOE gene and the APP and PSEN1 genes in adAD. This study includes mutation carriers (MC) and non-carriers (NC) from adAD families with mutations in APP (n = 28 and n = 25; MC and NC, respectively) and PSEN1 (n = 12 and n = 15; MC and NC, respectively) that represent the complete spectrum of disease: AD dementia (n = 8) and mild cognitive impairment (MCI, n = 15 and presymptomatic AD, n = 17). NC represented unimpaired normal aging. There was no significant difference in the distribution of APOE ε4 (absence vs. presence) between the APP vs. PSEN1 adAD genes and mutation status (MC vs. NC). However, episodic memory was significantly affected by the interaction between APOE and the APP vs. PSEN1 genes in MC. This was explained by favorable performance in the absence of APOE ε4 in PSEN1 compared to APP MC. Similar trends were seen in other cognitive functions. No significant associations between APOE ε4 and cognitive performance were obtained in NC. In conclusion, cognitive effects of APOE–adAD gene interaction were differentiated between the PSEN1 and APP mutation carriers, indicating epistasis.

Subcortical and Cortical Regions of Amyloid-β Pathology Measured by 11C-PiB PET Are Differentially Associated with Cognitive Functions and Stages of Disease in Memory Clinic Patients

BACKGROUND

The effect of regional brain amyloid-β (Aβ) pathology on specific cognitive functions is incompletely known.

OBJECTIVE

The relationship between Aβ and cognitive functions was investigated in this cross-sectional multicenter study of memory clinic patients.

METHODS

The participants were patients diagnosed with Alzheimer's disease (AD, n = 83), mild cognitive impairment (MCI, n = 60), and healthy controls (HC, n = 32), who had been scanned by 11C-PiB PET in 13 brain regions of both hemispheres and who had been assessed by cognitive tests covering seven domains.

RESULTS

Hierarchic multiple regression analyses were performed on each cognitive test as dependent variable, controlling for demographic characteristics and APOE status (block 1) and PiB measures in 13 brain regions (block 2) as independent variables. The model was highly significant for each cognitive test and most strongly for tests of episodic memory (learning and retention) versus PiB in putamen, visuospatially demanding tests (processing and retention) versus the occipital lobe, semantic fluency versus the parietal lobe, attention versus posterior gyrus cinguli, and executive function versus nucleus accumbens. In addition, education had a positively and APOE status a negatively significant effect on cognitive tests.

CONCLUSION

Five subcortical and cortical regions with Aβ pathology are differentially associated with cognitive functions and stages of disease in memory clinic patients.

Cerebrospinal Fluid YKL-40 and Neurogranin in Familial Alzheimer's Disease: A Pilot Study

BACKGROUND

YKL-40 and neurogranin are promising additional cerebrospinal fluid (CSF) biomarkers for Alzheimer's disease (AD) which reflect different underlying disease mechanisms.

OBJECTIVE

To compare the levels of CSF YKL-40 and neurogranin between asymptomatic carriers of familial AD (FAD) mutations (MC) and non-carriers (NC) from the same families. Another objective was to assess changes in YKL-40 and neurogranin, from the presymptomatic to clinical phase of FAD.

METHODS

YKL-40 and neurogranin, as well as Aβ42, total tau-protein, and phospho-tau, were measured in the CSF of 14 individuals carrying one of three FAD mutations, APPswe (p.KM670/671NL), APParc (p.E693G), and PSEN1 (p.H163Y), as well as in 17 NC from the same families. Five of the MC developed mild cognitive impairment (MCI) during follow-up.

RESULTS

In this pilot study, there was no difference in either CSF YKL-40 or neurogranin when comparing the presymptomatic MC to the NC. YKL-40 correlated positively with expected years to symptom onset and to age in both the MC and the NC, while neurogranin had no correlation to either variable in either of the groups. A subgroup of the participants underwent more than one CSF sampling in which half of the MC developed MCI during follow-up. The longitudinal data showed an increase in YKL-40 levels in the MC as the expected symptom onset approached. Neurogranin remained stable over time in both the MC and the NC.

CONCLUSION

These findings support a positive correlation between progression from presymptomatic to symptomatic AD and levels of CSF YKL-40, but not neurogranin.

Subjective working memory predicts objective memory in cognitively normal aging: a HUNT study

BACKGROUND

Recent studies have shown that subjective memory is multi-, rather than uni-dimensional, in line with the results of objective memory tests. The purpose of this study was to investigate whether there is an association between aspects of memory measured by the subjective Meta-Memory Questionnaire (MMQ) and aspects of memory measured by the objective Wechsler Memory Scale-III (WMS-III) and Wechsler Adult Intelligence Scale-III (WAIS-III) tests in cognitively normal older adults.

METHOD

The study subjects (n = 106) were cognitively normal, were aged 57-89 years and had participated in the third wave of the North-Trøndelag Health survey (HUNT3). All subjects had completed the MMQ, the WMS-III and the WAIS-III. Previous results from the MMQ (measured as the total MMQ score; the Component I score, related to long-term explicit declarative memory; and the Component II score, related to working/short-term memory) were compared with objective results from WMS-III (Logical Memory) and WAIS-III (Vocabulary and Letter-Number Sequencing) subtests. We conducted linear regression analyses with each objective memory test result as the dependent variable, and subjective memory measures and demographics as independent variables, as well as analyses of MMQ items vs. objective memory.

RESULTS

Subjective working memory impairment (Component II) was significant related to poor performance in objective episodic memory, according to correlation and regression analyses with demographic covariates. In contrast, ratings of impaired subjective declarative memory (Component I) were not related to poor objective memory performance.

CONCLUSIONS

Specific aspects of subjective memory related differentially to performance in specific objective memory tests. Clinicians and researchers might consider targeting working memory aspects of subjective memory tests, when seeking an estimate of objective memory performance.

Cortical microstructural correlates of astrocytosis in autosomal-dominant Alzheimer disease

OBJECTIVE

To study the macrostructural and microstructural MRI correlates of brain astrocytosis, measured with ¹¹C-deuterium-L-deprenyl (¹¹C-DED)-PET, in familial autosomal-dominant Alzheimer disease (ADAD).

METHODS

The total sample (n = 31) comprised ADAD mutation carriers (n = 10 presymptomatic, 39.2 ± 10.6 years old; n = 3 symptomatic, 55.5 ± 2.0 years old) and noncarriers (n = 18, 44.0 ± 13.7 years old) belonging to families with mutations in either the presenilin-1 or amyloid precursor protein genes. All participants underwent structural and diffusion MRI and neuropsychological assessment, and 20 participants (6 presymptomatic and 3 symptomatic mutation carriers and 11 noncarriers) also underwent ¹¹C-DED-PET.

RESULTS

Vertex-wise interaction analyses revealed a differential relationship between carriers and noncarriers in the association between ¹¹C-DED binding and estimated years to onset (EYO) and between cortical mean diffusivity (MD) and EYO. These differences were due to higher ¹¹C-DED binding in presymptomatic carriers, with lower binding in symptomatic carriers compared to noncarriers, and to lower cortical MD in presymptomatic carriers, with higher MD in symptomatic carriers compared to noncarriers. Using a vertex-wise local correlation approach, ¹¹C-DED binding was negatively correlated with cortical MD and positively correlated with cortical thickness.

CONCLUSIONS

Our proof-of-concept study is the first to show that microstructural and macrostructural changes can reflect underlying neuroinflammatory mechanisms in early stages of Alzheimer disease (AD). The findings support a role for neuroinflammation in AD pathogenesis, with potential implications for the correct interpretation of neuroimaging biomarkers as surrogate endpoints in clinical trials.

CSF Cholinergic Index, a New Biomeasure of Treatment Effect in Patients With Alzheimer's Disease

Alzheimer’s disease (AD) is a progressive disease with early degeneration of the central cholinergic neurons. Currently, three of four AD drugs act by inhibiting the acetylcholine (ACh) degrading enzyme, acetylcholinesterase (AChE). Efficacy of these drugs depends on available amount of ACh, which is biosynthesized by choline acetyltransferase (ChAT). We investigated whether treatment with a cholinesterase-inhibitor, galantamine, alters the relative levels of AChE to ChAT in cerebrospinal fluid (CSF) and whether levels of these CSF biomarkers correlate with in vivo AChE activity and nicotinic binding sites in the brain assessed by positron emission tomography (PET). Protein concentrations and activities of ChAT and AChE were measured in CSF of 18 patients with mild AD prior to and after 3 months of treatment with galantamine (n = 12) or placebo (n = 6), followed by nine additional months of galantamine treatment in all patients. A Cholinergic index was defined as the ratio of ChAT to AChE in CSF and was evaluated in relation to the in vivo AChE activity, the nicotinic binding sites and different measures of cognition. Besides an expected inhibition of AChE activity, galantamine treatment was accompanied by a mild increase in CSF ChAT activity. Thereby, the Cholinergic index was significantly increased in the Galantamine group (60% ± 14) after 3 months compared to baseline (p < 0.0023) or (p < 0.0004). This index remained high in the Galantamine group compared to baseline (54% ± 11) at 12 months follow-up, while it showed an increase in the Placebo group when they switched to active galantamine treatment (44% ± 14 vs. baseline, 61% ± 14 vs. 3 months, all p-values < 0.05). Furthermore, the in vivo brain AChE activity (assessed by PET) correlated with the CSF Cholinergic index at 12 months (r = 0.98, p < 0.001). The CSF Cholinergic index also correlated with ADAS-Cog and some other neuropsychological tests at 12 months. This is the first study assessing a CSF Cholinergic index in relation to treatment with a cholinesterase inhibitor. The treatment-specific increase in CSF ChAT activity suggests that cholinesterase-inhibitors may also increase the ACh-biosynthesis capacity in the patients. Additional studies are warranted to evaluate the utility of the CSF Cholinergic index as a biomeasure of therapeutic effect in AD.

Subjective working and declarative memory in dementia and normal aging

OBJECTIVE

Subjective memory complaints are common in both elderly individuals and patients with dementia. This study investigated the power of subjective memory, divided into declarative and working memory, to differentiate between patients with dementia and normal elderly individuals.

METHOD

Two groups of participants, patients with dementia (n = 117) and normal elderly individuals (n = 117), individually matched with regard to age, gender, and education. All subjects had participated in the third wave of the HUNT population health survey in Nord-Trøndelag County in Norway and completed the Meta-Memory Questionnaire (MMQ) in the HUNT study. The MMQ was subdivided into two components, one associated with declarative memory (episodic and semantic) and the other with working memory.

RESULTS

Patients with dementia reported significantly more subjective memory concerns than normal elderly individuals. The difference between working and declarative memory components was significantly greater in patients with dementia than in normal elderly individuals. This finding made it possible to differentiate patients with dementia from the normal elderly individuals. Mental and somatic health conditions did not significantly add power to differentiating the two groups.

CONCLUSION

In clinical and research applications, subjective memory components could contribute to differentiation of patients with dementia and normal elderly individuals by using self-reported impairment in working memory, rather than declarative memory.

Longitudinal cognitive decline in autosomal-dominant Alzheimer's disease varies with mutations in APP and PSEN1 genes

The purpose was to compare longitudinal cognitive changes in APP and PSEN1 gene mutation carriers and noncarriers from four autosomal-dominant Alzheimer's disease (ADAD) families across preclinical and early clinical stages of disease. Carriers (n = 34) with four different mutations (PSEN1_M146V, PSEN1_H163Y, APP_SWE, and APP_ARC) and noncarriers (n = 41) were followed up longitudinally with repeated cognitive assessments starting many years before the expected clinical onset. The relationship between cognition and years to expected clinical onset, education, age, and type of mutation was analyzed using mixed-effects models. Results showed an education-dependent and time-related cognitive decline with linear and quadratic predictors in mutation carriers. Cognitive decline began close to the expected clinical onset and was relatively rapid afterward in PSEN1 mutation carriers, whereas decline was slower and started earlier than 10 years before expected clinical onset in APP mutation carriers. In noncarriers, the decline was minimal across time in accordance with normal aging. These results suggest that phenotypes for onset and rate of cognitive decline vary with PSEN1 and APP genes, suggesting a behavioral heterogeneity in ADAD.

Tau PET imaging in neurodegenerative tauopathies-still a challenge

The accumulation of pathological misfolded tau is a feature common to a collective of neurodegenerative disorders known as tauopathies, of which Alzheimer's disease (AD) is the most common. Related tauopathies include progressive supranuclear palsy (PSP), corticobasal syndrome (CBS), Down's syndrome (DS), Parkinson's disease (PD), and dementia with Lewy bodies (DLB). Investigation of the role of tau pathology in the onset and progression of these disorders is now possible due the recent advent of tau-specific ligands for use with positron emission tomography (PET), including first- (e.g., [¹⁸F]THK5317, [¹⁸F]THK5351, [¹⁸F]AV1451, and [¹¹C]PBB3) and second-generation compounds [namely [¹⁸F]MK-6240, [¹⁸F]RO-948 (previously referred to as [¹⁸F]RO69558948), [¹⁸F]PI-2620, [¹⁸F]GTP1, [¹⁸F]PM-PBB3, and [¹⁸F]JNJ64349311 ([¹⁸F]JNJ311) and its derivative [¹⁸F]JNJ-067)]. In this review we describe and discuss findings from in vitro and in vivo studies using both initial and new tau ligands, including their relation to biomarkers for amyloid-β and neurodegeneration, and cognitive findings. Lastly, methodological considerations for the quantification of in vivo ligand binding are addressed, along with potential future applications of tau PET, including therapeutic trials.

Do adapted vignettes improve medical decision-making capacity for individuals with Alzheimer's disease?

Medical decision-making capacity (MDC) is known to decline in individuals with Alzheimer's disease (AD). The vignette method uses hypothetical information as a prerequisite for measuring the capacity to make well-informed decisions to clinical trials. Our aim was to investigate if adapted vignettes can help individuals with mild AD to assimilate information, make decisions and express them in an understandable way, compared to corresponding decisions based on linguistically more demanding vignettes, as measured by the Swedish Linguistic Instrument for Medical Decision-making (LIMD). Two vignettes from LIMD were altered linguistically with the aim to facilitate understanding for individuals with AD. An experimental within-subject design was used to study the influence on MDC of readability (original/adapted vignettes) and content (two different clinical trials). We included 24 patients with mild AD in this prospective study, which read all four vignettes along with a few other tests. This allowed us to investigate the association between MDC and cognitive function. Adapted vignettes did not yield significant differences regarding MDC as compared with original vignettes using a two-way repeated measures analysis of variance. A difference was found between the two clinical trials where LIMD score was significantly higher for Kidney disease than hypertension vignettes. Our results indicate that adapted vignettes may not improve MDC for individuals with mild AD. MDC was affected by which clinical trial the vignettes regarded, which implies that other factors affecting MDC need to be investigated, like length of text and vocabulary used.

Challenge levels of everyday technologies as perceived over five years by older adults with mild cognitive impairment

ABSTRACTBackground:In clinical practice, efficient and valid functional markers are needed to detect subtle cognitive and functional decline in mild cognitive impairment (MCI). This prospective study explored whether changes in perceived challenge of certain everyday technologies (ETs) can be used to detect signs of functional change in MCI.

METHODS

Baseline and five-year data from 37 older adults (mean age 67.5 years) with MCI regarding their perceived ability to use ET were used to generate Rasch-based ET item measures reflecting the relative challenge of 46 ETs. Actual differential item functioning in relation to time was analyzed based on these item measures. Data collection took place in 2008-2014.

RESULTS

Seven (15%) of the ETs included were perceived to be significantly more challenging to use at year five compared to at baseline, while 39 ETs (85%) were perceived to be equally challenging to use, despite the fact that the participants' perceived ability to use ET had decreased. Common characteristics among the ETs that became more challenging to use could not be identified. The dropout rate was 43%, which limits the power of the study.

CONCLUSIONS

Changes in the perceived challenge of ETs seem to capture functional change in persons with cognitive decline. Both easier and more challenging ETs typically used at home and in society need to be addressed to capture this functional change because significant changes occurred among ETs of all challenge levels and within all types of ETs.

Longitudinal changes of tau PET imaging in relation to hypometabolism in prodromal and Alzheimer's disease dementia

The development of tau-specific positron emission tomography (PET) tracers allows imaging in vivo the regional load of tau pathology in Alzheimer's disease (AD) and other tauopathies. Eighteen patients with baseline investigations enroled in a 17-month follow-up study, including 16 with AD (10 had mild cognitive impairment and a positive amyloid PET scan, that is, prodromal AD, and six had AD dementia) and two with corticobasal syndrome. All patients underwent PET scans with [¹⁸F]THK5317 (tau deposition) and [¹⁸F]FDG (glucose metabolism) at baseline and follow-up, neuropsychological assessment at baseline and follow-up and a scan with [¹¹C]PIB (amyloid-β deposition) at baseline only. At a group level, patients with AD (prodromal or dementia) showed unchanged [¹⁸F]THK5317 retention over time, in contrast to significant decreases in [¹⁸F]FDG uptake in temporoparietal areas. The pattern of changes in [¹⁸F]THK5317 retention was heterogeneous across all patients, with qualitative differences both between the two AD groups (prodromal and dementia) and among individual patients. High [¹⁸F]THK5317 retention was significantly associated over time with low episodic memory encoding scores, while low [¹⁸F]FDG uptake was significantly associated over time with both low global cognition and episodic memory encoding scores. Both patients with corticobasal syndrome had a negative [¹¹C]PIB scan, high [¹⁸F]THK5317 retention with a different regional distribution from that in AD, and a homogeneous pattern of increased [¹⁸F]THK5317 retention in the basal ganglia over time. These findings highlight the heterogeneous propagation of tau pathology among patients with symptomatic AD, in contrast to the homogeneous changes seen in glucose metabolism, which better tracked clinical progression.

Dual tracer tau PET imaging reveals different molecular targets for 11C-THK5351 and 11C-PBB3 in the Alzheimer brain

Purpose

Several tau PET tracers have been developed, but it remains unclear whether they bind to the same molecular target on the heterogeneous tau pathology. In this study we evaluated the binding of two chemically different tau-specific PET tracers (¹¹C-THK5351 and ¹¹C-PBB3) in a head-to-head, in vivo, multimodal design.

Methods

Nine patients with a diagnosis of mild cognitive impairment or probable Alzheimer’s disease and cerebrospinal fluid biomarker evidence supportive of the presence of Alzheimer’s disease brain pathology were recruited after thorough clinical assessment. All patients underwent imaging with the tau-specific PET tracers ¹¹C-THK5351 and ¹¹C-PBB3 on the same day, as well as imaging with the amyloid-beta-specific tracer ¹¹C-AZD2184, a T1-MRI sequence, and neuropsychological assessment.

Results

The load and regional distribution of binding differed between ¹¹C-THK5351 and ¹¹C-PBB3 with no statistically significant regional correlations observed between the tracers. The binding pattern of ¹¹C-PBB3, but not that of ¹¹C-THK5351, in the temporal lobe resembled that of ¹¹C-AZD2184, with strong correlations detected between ¹¹C-PBB3 and ¹¹C-AZD2184 in the temporal and occipital lobes. Global cognition correlated more closely with ¹¹C-THK5351 than with ¹¹C-PBB3 binding. Similarly, cerebrospinal fluid tau measures and entorhinal cortex thickness were more closely correlated with ¹¹C-THK5351 than with ¹¹C-PBB3 binding.

Conclusion

This research suggests different molecular targets for these tracers; while ¹¹C-PBB3 appeared to preferentially bind to tau deposits with a close spatial relationship to amyloid-beta, the binding pattern of ¹¹C-THK5351 fitted the expected distribution of tau pathology in Alzheimer’s disease better and was more closely related to downstream disease markers.

Electronic supplementary material

The online version of this article (10.1007/s00259-018-4012-5) contains supplementary material, which is available to authorized users.

Reduced penetrance of the PSEN1 H163Y autosomal dominant Alzheimer mutation: a 22-year follow-up study

Background

The range of onset ages within some PSEN1 families is wide, and a few cases of reduced penetrance of PSEN1 mutations have been reported. However, published data on reduced penetrance have been limited to clinical histories, often collected retrospectively and lacking biomarker information. We present a case of reduced penetrance of the PSEN1 H163Y mutation in a carrier prospectively followed for 22 years.

Methods

Two brothers (A and B), both carriers of the H163Y mutation, were followed between 1995 and 2017. They underwent repeated clinical evaluations, neuropsychological assessments, and cerebrospinal fluid analyses, as well as brain imaging examinations with structural magnetic resonance, [¹⁸F]fluorodeoxyglucose positron emission tomography, and [¹¹C]Pittsburgh compound B positron emission tomography.

Results

Brother A was followed between 44 and 64 years of age. Cognitive symptoms due to Alzheimer’s disease set in at the age of 54. Gradual worsening of symptoms resulted in admittance to a nursing home owing to dependence on others for all activities of daily living. He showed a curvilinear decline in cognitive function on neuropsychological tests, and changes on magnetic resonance imaging, positron emission tomography, and biomarkers in the cerebrospinal fluid supported a clinical diagnosis of Alzheimer’s disease. Brother A died at the age of 64 and fulfilled the criteria for definitive Alzheimer’s disease according to neuropathological examination results. Brother B was followed between the ages of 43 and 65 and showed no cognitive deterioration on repeated neuropsychological test occasions. In addition, no biomarker evidence of Alzheimer’s disease pathology was detected, either on imaging examinations or in cerebrospinal fluid.

Conclusions

The average (SD) age of symptom onset for PSEN1 H163Y is 51 ± 7 years according to previous studies. However, we present a case of a biomarker-verified reduction in penetrance in a mutation carrier who was still symptom-free at the age of 65. This suggests that other genetic, epigenetic, and/or environmental factors modify the onset age.

Electronic supplementary material

The online version of this article (10.1186/s13195-018-0374-y) contains supplementary material, which is available to authorized users.

A Cross-Validation of FDG- and Amyloid-PET Biomarkers in Mild Cognitive Impairment for the Risk Prediction to Dementia due to Alzheimer's Disease in a Clinical Setting

Assessments of brain glucose metabolism (18F-FDG-PET) and cerebral amyloid burden (11C-PiB-PET) in mild cognitive impairment (MCI) have shown highly variable performances when adopted to predict progression to dementia due to Alzheimer's disease (ADD). This study investigates, in a clinical setting, the separate and combined values of 18F-FDG-PET and 11C-PiB-PET in ADD conversion prediction with optimized data analysis procedures. Respectively, we investigate the accuracy of an optimized SPM analysis for 18F-FDG-PET and of standardized uptake value ratio semiquantification for 11C-PiB-PET in predicting ADD conversion in 30 MCI subjects (age 63.57±7.78 years). Fourteen subjects converted to ADD during the follow-up (median 26.5 months, inter-quartile range 30 months). Receiver operating characteristic analyses showed an area under the curve (AUC) of 0.89 and of 0.81 for, respectively, 18F-FDG-PET and 11C-PiB-PET. 18F-FDG-PET, compared to 11C-PiB-PET, showed higher specificity (1.00 versus 0.62, respectively), but lower sensitivity (0.79 versus 1.00). Combining the biomarkers improved classification accuracy (AUC = 0.96). During the follow-up time, all the MCI subjects positive for both PET biomarkers converted to ADD, whereas all the subjects negative for both remained stable. The difference in survival distributions was confirmed by a log-rank test (p = 0.002). These results indicate a very high accuracy in predicting MCI to ADD conversion of both 18F-FDG-PET and 11C-PiB-PET imaging, the former showing optimal performance based on the SPM optimized parametric assessment. Measures of brain glucose metabolism and amyloid load represent extremely powerful diagnostic and prognostic biomarkers with complementary roles in prodromal dementia phase, particularly when tailored to individual cases in clinical settings.

The Effects of Gene Mutations on Default Mode Network in Familial Alzheimer's Disease

Familial Alzheimer's disease (FAD) mutations have very high penetrance but age at onset and rate of disease progression differ. Neuroimaging and cerebrospinal fluid (CSF) examinations in mutation carriers (MCs) may provide an opportunity to identify early biomarkers that can be used to track disease progression from presymptomatic to the dementia stages of disease. The default mode network (DMN) is a resting state neuronal network composed of regions known to associate with amyloid deposition in AD. We hypothesized that functional connectivity in the DMN might change at pre-clinical stages in FAD MCs and correlate with changes in CSF biomarkers as a consequence of AD brain pathology. To test the hypothesis, we compared the functional connectivity in DMN between pre-MCs/MCs and non-carriers (NCs). No significant differences between pre-MCs and NCs were observed. When comparing all MCs with NCs, significant decreased functional connectivity in the right inferior parietal lobule, right precuneus, and left posterior cingulate cortex were found. We also found statistically significant correlations between CSF amyloid-β 42 and tau protein levels and average Z-score, a resting-state functional MRI measurement reflecting the degree of the correlation between a given voxel's time courses and the time courses corresponding to DMN, from the region with statistical difference. The observed disruption of DMN and pathological levels of AD CSF-biomarkers in FAD MCs are similar to the changes described in sporadic AD, which give further support that amyloid and tau pathology impairs neuronal and synaptic function.

Longitudinal uncoupling of cerebral perfusion, glucose metabolism, and tau deposition in Alzheimer's disease

INTRODUCTION

Cross-sectional findings using the tau tracer [¹⁸F]THK5317 (THK5317) have shown that [¹⁸F]fluorodeoxyglucose (FDG) positron emission tomography (PET) data can be approximated using perfusion measures (early-frame standardized uptake value ratio; ratio of tracer delivery in target to reference regions). In this way, a single PET study can provide both functional and molecular information.

METHODS

We included 16 patients with Alzheimer's disease who completed follow-up THK5317 and FDG studies 17 months after baseline investigations. Linear mixed-effects models and annual percentage change maps were used to examine longitudinal change.

RESULTS

Limited spatial overlap was observed between areas showing declines in THK5317 perfusion measures and FDG. Minimal overlap was seen between areas showing functional change and those showing increased retention of THK5317.

DISCUSSION

Our findings suggest a spatiotemporal offset between functional changes and tau pathology and a partial uncoupling between perfusion and metabolism, possibly as a function of Alzheimer's disease severity.

Selective impact of disease on short-term and long-term components of self-reported memory: a population-based HUNT study

BACKGROUND

Subjective memory is commonly considered to be a unidimensional measure. However, theories of performance-based memory suggest that subjective memory could be divided into more than one dimension.

OBJECTIVE

To divide subjective memory into theoretically related components of memory and explore the relationship to disease.

METHODS

In this study, various aspects of self-reported memory were studied with respect to demographics and diseases in the third wave of the HUNT epidemiological study in middle Norway. The study included all individuals 55 years of age or older, who responded to a nine-item questionnaire on subjective memory and questionnaires on health (n=18 633).

RESULTS

A principle component analysis of the memory items resulted in two memory components; the criterion used was an eigenvalue above 1, which accounted for 54% of the total variance. The components were interpreted as long-term memory (LTM; the first component; 43% of the total variance) and short-term memory (STM; the second component; 11% of the total variance). Memory impairment was significantly related to all diseases (except Bechterew's disease), most strongly to brain infarction, heart failure, diabetes, cancer, chronic obstructive pulmonary disease and whiplash. For most diseases, the STM component was more affected than the LTM component; however, in cancer, the opposite pattern was seen.

CONCLUSIONS

Subjective memory impairment as measured in HUNT contained two components, which were differentially associated with diseases.

The effects of different familial Alzheimer's disease mutations on APP processing in vivo

BACKGROUND

Disturbed amyloid precursor protein (APP) processing is considered to be central to the pathogenesis of Alzheimer's disease (AD). The autosomal dominant form of the disease, familial AD (FAD), may serve as a model for the sporadic form of AD. In FAD the diagnosis of AD is reliable and presymptomatic individuals carrying FAD mutations can give valuable insights into the earliest stages of the disease where therapeutic interventions are thought to be the most effective.

METHODS

In the current cross-sectional study, products of APP processing (e.g., sAPPα, sAPPβ, Aβ38, Aβ40 and Aβ42) were measured in the cerebrospinal fluid (CSF) of individuals carrying one of three FAD mutations, APPswe (p.KM670/671NL), APParc (p.E693G) and PSEN1 (p.H163Y), as well as in non-mutation carriers from the same families.

RESULTS

We observed pathological APP processing in presymptomatic carriers of FAD mutations, with different profiles of APP and Aβ isoforms in the three mutation carrier groups, APPswe (p.KM670/671NL), APParc (p.E693G) and PSEN1 (p.H163Y), except for the well-established decrease in CSF Aβ42 that was found with all mutations.

CONCLUSIONS

These findings add to the current evidence that AD pathophysiology differs between disease-causing mutations and can be monitored in the presymptomatic disease stage by CSF analyses. This may also be important from a therapeutic standpoint, by opening a window to monitor effects of disease-modifying drugs on AD pathophysiology.

Rapid cognitive screening in multiple sclerosis accomplished by the Free Recall and Recognition Test

This study sought to investigate the feasibility of the Free Recall and Recognition Test (FRRT) as a practical screening tool for cognitive impairment in multiple sclerosis (MS). Persons with MS (n =227) were consecutively recruited and assessed with four cognitive tests; FRRT, Symbol Digit Modalities Test (SDMT), Paced Auditory Serial Addition Test (PASAT), and the Mini-Mental State Examination (MMSE). Disease severity was assessed by the Expanded Disability Status Scale (EDSS). The FRRT, which was completed by 99% of the cohort in approximately 5 minutes per assessment, correlated significantly with the other cognitive tests, as well as with the disease severity rating. A cut-off of 4 for the FRRT recall rendered 90% sensitivity and 25% specificity, and a cut-off of 4.2 for the FRRT recognition resulted in 70% sensitivity and 51% specificity. We conclude that the FRRT proved feasible as a practical screening tool for cognitive impairment in MS within a clinical setting. Multiple Sclerosis 2007; 13: 272–274. http://msj.sagepub.com

Regional tau deposition measured by [18F]THK5317 positron emission tomography is associated to cognition via glucose metabolism in Alzheimer's disease

Background

The recent development of tau-specific positron emission tomography (PET) tracers has allowed in vivo quantification of regional tau deposition and offers the opportunity to monitor the progression of tau pathology along with cognitive impairment. In this study, we investigated the relationships of cerebral tau deposition ([¹⁸F]THK5317-PET) and metabolism ([¹⁸F]FDG-PET) with concomitant cognitive function in patients with probable Alzheimer’s disease (AD).

Methods

Nine patients diagnosed with AD dementia and 11 with prodromal AD (mild cognitive impairment, amyloid-positive on [¹¹C]PiB-PET) were included in this study. All patients underwent PET scans using each tracer, as well as episodic memory and global cognition assessment. Linear models were used to investigate the association of regional [¹⁸F]THK5317 retention and [¹⁸F]FDG uptake with cognition. The possible mediating effect of local metabolism on the relationship between tau deposition and cognitive performance was investigated using mediation analyses.

Results

Significant negative associations were found between [¹⁸F]THK5317 regional retention, mainly in temporal regions, and both episodic memory and global cognition. Significant positive associations were found between [¹⁸F]FDG regional uptake and cognition. The association of [¹⁸F]FDG with global cognition was regionally more extensive than that of [¹⁸F]THK5317, while the opposite was observed with episodic memory, suggesting that [¹⁸F]THK5317 retention might be more sensitive than [¹⁸F]FDG regional uptake to early cognitive impairment. Finally, [¹⁸F]FDG uptake had a mediating effect on the relationship between [¹⁸F]THK5317 retention in temporal regions and global cognition.

Conclusions

These findings suggest a mediating role for local glucose metabolism in the observed association between in vivo tau deposition and concomitant cognitive impairment in AD.

Electronic supplementary material

The online version of this article (doi:10.1186/s13195-016-0204-z) contains supplementary material, which is available to authorized users.

Targeted delivery of nerve growth factor to the cholinergic basal forebrain of Alzheimer's disease patients: application of a second-generation encapsulated cell biodelivery device

Background

Targeted delivery of nerve growth factor (NGF) has emerged as a potential therapy for Alzheimer’s disease (AD) due to its regenerative effects on basal forebrain cholinergic neurons. This hypothesis has been tested in patients with AD using encapsulated cell biodelivery of NGF (NGF-ECB) in a first-in-human study. We report our results from a third-dose cohort of patients receiving second-generation NGF-ECB implants with improved NGF secretion.

Methods

Four patients with mild to moderate AD were recruited to participate in an open-label, phase Ib dose escalation study with a 6-month duration. Each patient underwent stereotactic implant surgery with four NGF-ECB implants targeted at the cholinergic basal forebrain. The NGF secretion of the second-generation implants was improved by using the Sleeping Beauty transposon gene expression technology and an improved three-dimensional internal scaffolding, resulting in production of about 10 ng NGF/device/day.

Results

All patients underwent successful implant procedures without complications, and all patients completed the study, including implant removal after 6 months. Upon removal, 13 of 16 implants released NGF, 8 implants released NGF at the same rate or higher than before the implant procedure, and 3 implants failed to release detectable amounts of NGF. Of 16 adverse events, none was NGF-, or implant-related. Changes from baseline values of cholinergic markers in cerebrospinal fluid (CSF) correlated with cortical nicotinic receptor expression and Mini Mental State Examination score. Levels of neurofilament light chain (NFL) protein increased in CSF after NGF-ECB implant, while glial fibrillary acidic protein (GFAP) remained stable.

Conclusions

The data derived from this patient cohort demonstrate the safety and tolerability of sustained NGF release by a second-generation NGF-ECB implant to the basal forebrain, with uneventful surgical implant and removal of NGF-ECB implants in a new dosing cohort of four patients with AD.

Trial registration

ClinicalTrials.gov identifier: NCT01163825. Registered on 14 Jul 2010.

Correlations between Alzheimer's Disease Cerebrospinal Fluid Biomarkers and Cerebral Glucose Metabolism after 12 Months of Phenserine Treatment

New therapeutic strategies in Alzheimer's disease (AD) are focused on targeting amyloid-β (Aβ) to modify the underlying cause of the disease rather than just the symptoms. The aim of this study was to investigate the long-term effects of treatment with the anti-Aβ compound phenserine on (i) cerebrospinal fluid (CSF) biomarkers for Aβ and tau pathology and (ii) brain metabolism as assessed by the regional cerebral metabolic rate for glucose (rCMRglc), using positron emission tomography. Twenty patients with mild AD were included in the study and after 12 months treatment with phenserine, CSF Aβ40 and α- and β-secretase-cleaved soluble amyloid-β protein precursor (sAβPP) levels had significantly increased and rCMRglc had stabilized. Levels of CSF Aβ40 and sAβPP correlated positively with rCMRglc and cognition while CSF Aβ42 levels, the Aβ42/40 ratio, P-tau, and T-tau correlated negatively with rCMRglc and cognition. In summary, long-term phenserine treatment resulted in increased levels of CSF Aβ40, sAβPPα, and sAβPPβ, which positively correlated with improvements in rCMRglc and cognition. The study illustrates the value of using biomarkers in the CSF and brain for evaluation of drug effects.

Imaging in-vivo tau pathology in Alzheimer's disease with THK5317 PET in a multimodal paradigm

Purpose

The aim of this study was to explore the cerebral distribution of the tau-specific PET tracer [¹⁸F]THK5317 (also known as (S)-[¹⁸F]THK5117) retention in different stages of Alzheimer’s disease; and study any associations with markers of hypometabolism and amyloid-beta deposition.

Methods

Thirty-three individuals were enrolled, including nine patients with Alzheimer’s disease dementia, thirteen with mild cognitive impairment (MCI), two with non-Alzheimer’s disease dementia, and nine healthy controls (five young and four elderly). In a multi-tracer PET design [¹⁸F]THK5317, [¹¹C] Pittsburgh compound B ([¹¹C]PIB), and [¹⁸F]FDG were used to assess tau pathology, amyloid-beta deposition and cerebral glucose metabolism, respectively. The MCI patients were further divided into MCI [¹¹C]PIB-positive (n = 11) and MCI [¹¹C]PIB-negative (n = 2) groups.

Results

Test-retest variability for [¹⁸F]THK5317-PET was very low (1.17–3.81 %), as shown by retesting five patients. The patients with prodromal (MCI [¹¹C]PIB-positive) and dementia-stage Alzheimer’s disease had significantly higher [¹⁸F]THK5317 retention than healthy controls (p = 0.002 and p = 0.001, respectively) in areas exceeding limbic regions, and their discrimination from this control group (using the area under the curve) was >98 %. Focal negative correlations between [¹⁸F]THK5317 retention and [¹⁸F]FDG uptake were observed mainly in the frontal cortex, and focal positive correlations were found between [¹⁸F]THK5317 and [¹¹C]PIB retentions isocortically. One patient with corticobasal degeneration syndrome and one with progressive supranuclear palsy showed no [¹¹C]PIB but high [¹⁸F]THK5317 retentions with a different regional distribution from that in Alzheimer’s disease patients.

Conclusions

The tau-specific PET tracer [¹⁸F]THK5317 images in vivo the expected regional distribution of tau pathology. This distribution contrasts with the different patterns of hypometabolism and amyloid-beta deposition.

Electronic supplementary material

The online version of this article (doi:10.1007/s00259-016-3363-z) contains supplementary material, which is available to authorized users.

Concordance and Diagnostic Accuracy of [11C]PIB PET and Cerebrospinal Fluid Biomarkers in a Sample of Patients with Mild Cognitive Impairment and Alzheimer's Disease

BACKGROUND

Alzheimer's disease (AD) pathology can be quantified in vivo using cerebrospinal fluid (CSF) levels of amyloid-β1-42 (Aβ1-42), total-tau (t-tau), and phosphorylated tau (p-tau181p), as well as with positron emission tomography (PET) using [(11)C]Pittsburgh compound-B ([(11)C]PIB). Studies assessing concordance between these measures, however, have provided conflicting results. Moreover, it has been proposed that [(11)C]PIB PET may be of greater clinical utility in terms of identifying patients with mild cognitive impairment (MCI) who will progress to the dementia phase of AD.

OBJECTIVE

To determine concordance and classification accuracy of CSF biomarkers and [(11)C]PIB PET in a cohort of patients with MCI and AD.

METHODS

68 patients (MCI, n = 33; AD, n = 35) underwent [(11)C]PIB PET and CSF sampling. Cutoffs of >1.41 ([(11)C]PIB), <450 pg/mL-and a more lenient cutoff of 550 pg/mL-(Aβ1-42), <6.5 (Aβ1-42/p-tau181p), and 1.14 (Aβ1-42/t-tau), were used to determine concordance. Logistic regression was used to determine classification accuracy with respect to stable MCI (sMCI) versus MCI who progressed to AD (pMCI).

RESULTS

Concordance between [(11)C]PIB and Aβ1-42 was highest for sMCI (67%), followed by AD (60%) and pMCI (33%). Agreement was increased across groups using Aβ1-42 <550 pg/mL, or Aβ1-42 to tau ratios. Logistic regression showed that classification accuracy of [(11)C]PIB, between sMCI and pMCI, was superior to Aβ1-42 (73% versus 58%), Aβ1-42/t-tau (63%), and Aβ1-42/p-tau181p (65%).

CONCLUSION

In the present study, [(11)C]PIB proved a better predictor of progression to AD in patients with MCI, relative to CSF measures of Aβ1-42 or Aβ1-42/tau. Discordance between PET and CSF markers for Aβ1-42 suggests they cannot be used interchangeably, as is currently the case.

Comparison of Early-Phase 11C-Deuterium-l-Deprenyl and 11C-Pittsburgh Compound B PET for Assessing Brain Perfusion in Alzheimer Disease

The PET tracer (11)C-deuterium-L-deprenyl ((11)C-DED) has been used to visualize activated astrocytes in vivo in patients with Alzheimer disease (AD). In this multitracer PET study, early-phase (11)C-DED and (11)C-Pittsburgh compound B ((11)C-PiB) (eDED and ePiB, respectively) were compared as surrogate markers of brain perfusion, and the extent to which (11)C-DED binding is influenced by brain perfusion was investigated.

METHODS

(11)C-DED, (11)C-PiB, and (18)F-FDG dynamic PET scans were obtained in age-matched groups comprising AD patients (n = 8), patients with mild cognitive impairment (n = 17), and healthy controls (n = 16). A modified reference Patlak model was used to quantify (11)C-DED binding. A simplified reference tissue model was applied to both (11)C-DED and (11)C-PiB to measure brain perfusion relative to the cerebellar gray matter (R1) and binding potentials. (11)C-PiB retention and (18)F-FDG uptake were also quantified as target-to-pons SUV ratios in 12 regions of interest (ROIs).

RESULTS

The strongest within-subject correlations with the corresponding R1 values (R1,DED and R1,PiB, respectively) and with (18)F-FDG uptake were obtained when the eDED and ePiB PET data were measured 1-4 min after injection. The optimum eDED/ePiB intervals also showed strong, significant ROI-based intersubject Pearson correlations with R1,DED/R1,PiB and with (18)F-FDG uptake, whereas (11)C-DED binding was largely independent of brain perfusion, as measured by eDED. Corresponding voxelwise correlations confirmed the ROI-based results. Temporoparietal eDED or ePiB brain perfusion measurements were highly discriminative between patient and control groups, with discriminative ability statistically comparable to that of temporoparietal (18)F-FDG glucose metabolism. Hypometabolism extended over wider regions than hypoperfusion in patient groups compared with controls.

CONCLUSION

The 1- to 4-min early-frame intervals of (11)C-DED or (11)C-PiB are suitable surrogate measures for brain perfusion. (11)C-DED binding is independent of brain perfusion, and thus (11)C-DED PET can provide information on both functional (brain perfusion) and pathologic (astrocytosis) aspects from a single PET scan. In comparison with glucose metabolism, early-phase (11)C-DED and (11)C-PiB perfusion appear to provide complementary rather than redundant information.

Diverging longitudinal changes in astrocytosis and amyloid PET in autosomal dominant Alzheimer's disease

See Schott and Fox (doi: 10.1093/brain/awv405 ) for a scientific commentary on this article.

Alzheimer’s disease is a multifactorial dementia disorder characterized by early amyloid-β, tau deposition, glial activation and neurodegeneration, where the interrelationships between the different pathophysiological events are not yet well characterized. In this study, longitudinal multitracer positron emission tomography imaging of individuals with autosomal dominant or sporadic Alzheimer’s disease was used to quantify the changes in regional distribution of brain astrocytosis (tracer ¹¹ C-deuterium-L-deprenyl), fibrillar amyloid-β plaque deposition ( ¹¹ C-Pittsburgh compound B), and glucose metabolism ( ¹⁸ F-fluorodeoxyglucose) from early presymptomatic stages over an extended period to clinical symptoms. The 52 baseline participants comprised autosomal dominant Alzheimer’s disease mutation carriers ( n = 11; 49.6 ± 10.3 years old) and non-carriers ( n = 16; 51.1 ± 14.2 years old; 10 male), and patients with sporadic mild cognitive impairment ( n = 17; 61.9 ± 6.4 years old; nine male) and sporadic Alzheimer’s disease ( n = 8; 63.0 ± 6.5 years old; five male); for confidentiality reasons, the gender of mutation carriers is not revealed. The autosomal dominant Alzheimer’s disease participants belonged to families with known mutations in either presenilin 1 ( PSEN1 ) or amyloid precursor protein ( APPswe or APParc ) genes. Sporadic mild cognitive impairment patients were further divided into ¹¹ C-Pittsburgh compound B-positive ( n = 13; 62.0 ± 6.4; seven male) and ¹¹ C-Pittsburgh compound B-negative ( n = 4; 61.8 ± 7.5 years old; two male) groups using a neocortical standardized uptake value ratio cut-off value of 1.41, which was calculated with respect to the cerebellar grey matter. All baseline participants underwent multitracer positron emission tomography scans, cerebrospinal fluid biomarker analysis and neuropsychological assessment. Twenty-six of the participants underwent clinical and imaging follow-up examinations after 2.8 ± 0.6 years. By using linear mixed-effects models, fibrillar amyloid-β plaque deposition was first observed in the striatum of presymptomatic autosomal dominant Alzheimer’s disease carriers from 17 years before expected symptom onset; at about the same time, astrocytosis was significantly elevated and then steadily declined. Diverging from the astrocytosis pattern, amyloid-β plaque deposition increased with disease progression. Glucose metabolism steadily declined from 10 years after initial amyloid-β plaque deposition. Patients with sporadic mild cognitive impairment who were ¹¹ C-Pittsburgh compound B-positive at baseline showed increasing amyloid-β plaque deposition and decreasing glucose metabolism but, in contrast to autosomal dominant Alzheimer’s disease carriers, there was no significant longitudinal decline in astrocytosis over time. The prominent initially high and then declining astrocytosis in autosomal dominant Alzheimer’s disease carriers, contrasting with the increasing amyloid-β plaque load during disease progression, suggests astrocyte activation is implicated in the early stages of Alzheimer’s disease pathology.

Including a subject-paced trial may make the PASAT more acceptable for MS patients

The Paced Auditory Serial Addition Test (PASAT) is regularly used in the evaluation of cognition in multiple sclerosis (MS). However, the test may impose frustration, distress, and anxiety in patients, which may result in refusal to participate by many patients.

OBJECTIVES

In this study, a subject- and experimenter-paced PASAT was compared and analyzed, with regard to independent measures of cognitive functions, as well as disability, fatigue, depression, and anxiety.

METHODS

A population-based sample of patients with MS (n = 34; mean age 47.2 ± 8.6) was examined with the PASAT, including a subject-paced condition, in addition to the standard experimenter-paced conditions using three levels of interstimuli intervals (ISI: 3.0, 2.5, and 2.0 s). A comprehensive set of neuropsychological tests, measures of disease severity, fatigue, anxiety, and depression were studied as potentially associated factors.

RESULTS

Subject- and experimenter-paced PASAT performance correlated significantly and the subject-paced administration correlated even higher with measures of information processing speed, executive function, attention, and working memory than standard experimenter-paced administration of PASAT.

DISCUSSION

The associations between PASAT performance and measures of fatigue, anxiety, and depression were not significant.

CONCLUSION

The results indicate that the altered PASAT procedure measures the same cognitive functions in MS as the standard procedure. At the same time, the altered procedure may make the PASAT more user-friendly for patients with MS.

Preclinical cerebrospinal fluid and volumetric magnetic resonance imaging biomarkers in Swedish familial Alzheimer's disease

BACKGROUND

It is currently believed that therapeutic interventions will be most effective when introduced at the preclinical stage of Alzheimer's disease (AD). This underlines the importance of biomarkers to detect AD pathology in vivo before clinical disease onset.

OBJECTIVE

To examine the evolution of cerebrospinal fluid (CSF) biomarker and brain structure changes in the preclinical phase of familial AD.

METHODS

The study included members from four Swedish families at risk for carrying an APPswe, APParc, PSEN1 H163Y, or PSEN1 I143T mutation. Magnetic resonance imaging (MRI) scans were obtained from 13 mutation carriers (MC) and 20 non-carriers (NC) and analyzed using vertex-based analyses of cortical thickness and volume. CSF was collected from 10 MC and 12 NC from familial AD families and analyzed for Aβ42, total tau (T-tau) and phospho-tau (P-tau).

RESULTS

The MC had significantly lower levels of CSF Aβ42 and higher levels T-tau and P-tau than the NC. There was a trend for a decrease in Aβ42 15-20 years before expected onset of clinical symptoms, while increasing T-tau and P-tau was not found until close to the expected clinical onset. The MC had decreased volume on MRI in the left precuneus, superior temporal gyrus, and fusiform gyrus.

CONCLUSIONS

Aberrant biomarker levels in CSF as well as regional brain atrophy are present in preclinical familial AD, several years before the expected onset of clinical symptoms.

White matter changes in familial Alzheimer's disease

BACKGROUND

Familial Alzheimer's disease (FAD) resulting from gene mutations in PSEN1, PSEN2 and APP is associated with changes in the brain.

OBJECTIVE

The aim of this study was to investigate changes in grey matter (GM), white matter (WM) and the cerebrospinal fluid (CSF) in FAD.

SUBJECTS

Ten mutation carriers (MCs) with three different mutations in PSEN1 and APP and 20 noncarriers (NCs) were included in the study. Three MCs were symptomatic and seven were presymptomatic (pre-MCs).

METHODS

Whole-brain GM volume as well as fractional anisotropy (FA) and mean diffusivity (MD) using voxel-based morphometry and tract-based spatial statistics analyses, respectively, were compared between MCs and NCs. FA and MD maps were obtained from diffusion tensor imaging.

RESULTS

A significant increase in MD was found in the left inferior longitudinal fasciculus, cingulum and bilateral superior longitudinal fasciculus in pre-MCs compared with NCs. After inclusion of the three symptomatic MCs in the analysis, the regions became wider. The mean MD of these regions showed significant negative correlation with the CSF level of Aβ42, and positive correlations with P-tau181p and T-tau. No differences were observed in GM volume and FA between the groups.

CONCLUSIONS

The results of this study suggest that FAD gene mutations affect WM diffusivity before changes in GM volume can be detected. The WM changes observed were related to changes in the CSF, with similar patterns previously observed in sporadic Alzheimer's disease.

Changing everyday activities and technology use in mild cognitive impairment

Introduction

Knowledge of the conditions under which older adults facing cognitive decline engage in everyday activities is of major importance for occupational therapists in designing supportive interventions. This study aimed to investigate perceived activity involvement over time and its longitudinal relationship to perceived ability to use everyday technology in older adults with mild cognitive impairment.

Method

Thirty-seven older adults with mild cognitive impairment at inclusion were assessed over 4 years. Overall and item-specific activity involvement were analyzed using mixed-linear-effect modeling and differential item functioning. Furthermore, overall activity involvement and ability in everyday technology use were correlated.

Results

Overall activity involvement decreased significantly over time. When adjusting for declining ability in the sample, actual differential item functioning indicated descending involvement in seven of 15 activities, while eight activities were stable. All leisure activities descended. The positive correlations between activity involvement and ability in everyday technology use became stronger over time.

Conclusion

Variations across activities and time-points suggest that occupational therapists should repeatedly monitor the increasingly associated aspects of activity involvement and ability to use everyday technology in persons with cognitive decline.

Amount and type of everyday technology use over time in older adults with cognitive impairment

OBJECTIVES

This two-year study examined everyday technology (ET) use in older adults with mild cognitive impairment (MCI) testing five predefined theoretical assumptions regarding factors potentially influencing the amount of ET used in everyday life.

METHODS

Data from 37 participants with MCI were collected at inclusion, six, 12, and 24 months, on the type and amount of ET used and how difficult this was, activity involvement, and cognitive and diagnostic status. These variables were, together with age group (55-64, 65-74, or 75-84 years) and educational level, analysed in a mixed-linear-effect model.

RESULTS

A significant decrease in the overall amount of ET used was found over time, but the number of users of specific ETs both decreased and increased. Increasing perceived difficulty in ET use, less activity involvement, decreasing cognitive status, and belonging to the oldest age group significantly decreased ET use. Two years after inclusion 42% of the participants had converted to dementia, but neither change in diagnostic status nor length of education contributed significantly to the predictive model.

CONCLUSION

Over time, a decreasing use of ET was shown in this sample with MCI. This process was influenced by several aspects important to consider in occupational therapy intervention planning.

Degree of abnormality is associated with rate of change in measures of beta-amyloid, glucose metabolism and cognition in an autopsy-verified Alzheimer's disease case

The degree of abnormality and rate of change in cognitive functions, positron emission tomography Pittsburg compound B (PET PIB), and fluorodeoxyglucose (FDG) measures were studied for 8 years in an autopsy-confirmed Alzheimer's disease (AD) patient, who died 61 years old (Mini-Mental State Examination (MMSE) score 7). At first encounter with medical care, the patient was very mildly demented (MMSE score 27). She had four cognitive assessments and two examinations with PET PIB and FDG in 23 bilateral brain regions. The onset of cognitive decline was retrospectively estimated to have started in the early forties. The degree of impairment was inversely related to the rate of decline. A similar relationship was seen between the rate of change and the level of abnormality in both PIB and FDG. To conclude, rate of change in cognition, PIB, and FDG was associated with the degree of abnormality.

Cognitive predictors of medical decision-making capacity in mild cognitive impairment and Alzheimer's disease

OBJECTIVE

Impaired capacity to make decisions in everyday life and situations of medical treatment is an inevitable consequence of the cognitive decline in Alzheimer's disease (AD). The objective of this study was to identify the most powerful cognitive component(s) that best predicted medical decision-making capacity (MDMC) in patients with AD and mild cognitive impairment.

METHOD

Three groups of subjects participated in the study: patients with AD (n = 20), mild cognitive impairment (n = 21), and healthy control subjects (n = 33). MDMC was assessed by the linguistic instrument for medical decision-making (LIMD) and related to demographics and 27 cognitive test measures.

RESULTS

The cognitive tests were found to aggregate into four components using a principle component analysis. The four components, which correspond to verbal knowledge, episodic memory, cognitive speed, and working memory, accounted for 73% of the variance in LIMD according to a stepwise regression analysis. Verbal knowledge was the most powerful predictor of LIMD (beta = 0.66) followed by episodic memory (beta = 0.43), cognitive speed (beta = 0.32), and working memory (beta = 0.23). The best single test as shown by the highest correlation with LIMD was Reading speed (R = 0.77).

CONCLUSION

Multiple factors are involved in MDMC in subjects with cognitive impairment. The component of verbal knowledge was the best predictor of MDMC and Reading speed was the most important single cognitive test measurement, which assessed both rapid Reading and understanding of text.