Exploring the validity of mild cognitive impairment (MCI) subtypes: Multiple-domain amnestic MCI is the only identifiable subtype at longitudinal follow-up

Longitudinal trajectories of general cognitive and daily functions in data-driven subtypes of MCI: A longitudinal cohort analysis of older adults

OBJECTIVES

To derive data-driven subtypes of mild cognitive impairment (MCI) and characterize the complicated changes of general cognitive and daily functions over time in MCI subtypes.

METHODS

A total of 813 subjects diagnosed as MCI at baseline from the Alzheimer's Disease Neuroimaging Initiative (ADNI) were included. Data-driven MCI subtypes were derived from group-based multi-trajectory modeling (GBMTM) analyses using longitudinal measurement scores in the cognitive domains of visuospatial function, language, and executive function. General cognitive and daily functions were measured by the Mini-Mental State Examination (MMSE) and the Functional Assessment Questionnaire (FAQ), respectively, whose longitudinal trajectory changes were depicted by Linear mixed models.

RESULTS

Three MCI subtypes were derived, which were defined as "Cognitive decline group", "Mild cognitive decline group" and "No cognitive decline group". The "Mild cognitive decline group" had the highest percentage in the sample (46.2 %), followed by the "No cognitive decline group" (35.2 %). Patients in the "Cognitive decline group" had the highest mean age (74.69 years) at baseline, the highest APOE ε4 carriers (63.2 %), and the greatest dementia conversion rate (77.0 %). The changes in MMSE and FAQ score trajectories were fastest in the "Cognitive decline group" in the first 36 months and most slowly in the "No cognitive decline group".

CONCLUSION

MCI individuals could be subdivided into more fine-grained cognitive subtypes, and identifying these distinct MCI subtypes and their different trajectories of cognitive decline may have important prognostic value for improving clinical course prediction.

Longitudinal trajectory effects of different MCI subtypes on general cognitive and daily functions in a population-based cohort of older adults

OBJECTIVES

To identify different mild cognitive impairment (MCI) phenotypes based on substantial relative impairment in specific cognitive domains and then characterize the complex process of general cognitive and daily functions over time in older adults with these MCI subtypes.

METHODS

A total of 1020 participants with MCI at baseline from the Alzheimer's Disease Neuroimaging Initiative (ADNI) were recruited. MCI subtypes were obtained based on neuropsychological tests in five cognitive domains: memory (M), visuospatial function (V), language (L), processing speed (P), and executive function (E). General cognitive function and daily function were measured by the Mini-Mental State Examination (MMSE) and the Functional Assessment Questionnaire (FAQ), respectively. Linear mixed models were fitted to curve their trajectories across different MCI subtypes.

RESULTS

Considering visuospatial function, subtypes were MO (memory impaired only), M&V (memory and visuospatial function impaired) and M&nV (memory impaired and visuospatial function non-impaired). Similar subtypes and naming rules were obtained based on language, executive function, and processing speed. Further, depending on the number of relative impaired cognitive domains M&S and M&M were obtained. Participants with MO had the highest prevalence in the sample (53.4 %), followed by M&nV (31.1 %). Participants with M&V had the highest mean age (74.69 years) at baseline and the greatest dementia conversion rate (53.2 %). The MMSE and FAQ score trajectories changed most slowly in participants with MO while fastest in those with M&V. Obvious different trajectories of both MMSE and FAQ scores were observed across different subtypes based on visuospatial function and executive function.

CONCLUSION

Compared to MO, individuals with multi-dimensional cognitive impairment have worse general cognitive and daily functions, especially for those with M&V.

Estimating presymptomatic episodic memory impairment using simple hand movement tests: A cross-sectional study of a large sample of older adults

INTRODUCTION

Finding low-cost methods to detect early-stage Alzheimer's disease (AD) is a research priority for neuroprotective drug development. Presymptomatic Alzheimer's is associated with gait impairment but hand motor tests, which are more accessible, have hardly been investigated. This study evaluated how home-based Tasmanian (TAS) Test keyboard tapping tests predict episodic memory performance.

METHODS

1169 community participants (65.8 ± 7.4 years old; 73% female) without cognitive symptoms completed online single-key and alternate-key tapping tests and episodic memory, working memory, and executive function cognitive tests.

RESULTS

All single-key (R2 adj  = 8.8%, ΔAIC = 5.2) and alternate-key (R2 adj  = 9.1%, ΔAIC = 8.8) motor features predicted episodic memory performance relative to demographic and mood confounders only (R2 adj  = 8.1%). No tapping features improved estimation of working memory.

DISCUSSION

Brief self-administered online hand movement tests predict asymptomatic episodic memory impairment. This provides a potential low-cost home-based method for stratification of enriched cohorts.

HIGHLIGHTS

We devised two brief online keyboard tapping tests to assess hand motor function. 1169 cognitively asymptomatic adults completed motor- and cognitive tests online. Impaired hand motor function predicted reduced episodic memory performance. This brief self-administered test may aid stratification of community cohorts.

Metacognitive Strategy Training Improves Decision-Making Abilities in Amnestic Mild Cognitive Impairment

Mild cognitive impairment (MCI) is associated with deficits in decision-making, which is of utmost importance for daily functioning. Despite evidence of declined decision-making abilities, research on decision-making interventions for MCI is scarce. As metacognition seems to play an important role in decision-making, the present study's aim was to examine whether a metacognitive strategy training can improve MCI patients' decision-making abilities. Older adults-patients of a day care center, diagnosed with amnestic MCI (n = 55) were randomly allocated in two groups, which were matched in gender, age and educational level. Τhe experimental group (n = 27, 18 women, mean age = 70.63, mean years of education = 13.44) received the metacognitive strategy training in parallel with the cognitive and physical training programs of the day care center, and the active control group (n = 28, 21 women, mean age = 70.86, mean years of education = 13.71) received only the cognitive and physical training of the center. The metacognitive strategy training included three online meeting sessions that took place once per week. The basis of the intervention was using analytical thinking, by answering four metacognitive-strategic questions, to make decisions about everyday situations. To examine the efficacy of the training, the ability to make decisions about everyday decision-making situations and the ability to apply decision rules were measured. Both groups participated in a pre-test session and a post-test session, while the experimental group also participated in a follow-up session, one month after the post-test session. The results showed that the experimental group improved its ability to decide, based on analytical thinking, about economic and healthcare-related everyday decision-making situations after they received the metacognitive strategy training. This improvement was maintained one month later. However, the ability to apply decision rules, which requires high cognitive effort, did not improve. In conclusion, it is important that some aspects of the analytical decision-making ability of amnestic MCI patients were improved due to the present metacognitive intervention.

Saccadic Eye Movements in Patients with Mild Cognitive Impairment: A Longitudinal Study

Saccadic eye movements are one of the sensitive and noninvasive methods to help monitor the cognitive course of mild cognitive impairment (MCI). The study aimed to evaluate both pro and anti-saccade longitudinally and the relationship between cognitive functions and eye movements in MCI subgroups and healthy controls (HCs) at a two-year follow-up. This study revealed that the anti-saccade anticipatory responses decreased in amnestic MCI (aMCI). Correct vertical pro-saccades increased in non-amnestic MCI (naMCI), while the express saccades decreased. Our study demonstrated that longer than two years of follow-up is necessary to monitor the course of MCI. Findings of the relationships between longitudinal changes of saccades and cognitive measurements demonstrated the usability of eye movements in evaluating the process of MCI.

Mild Cognitive Impairment, Reversion Rates, and Associated Factors: Comparison of Two Diagnostic Approaches

BACKGROUND

As mild cognitive impairment (MCI) is typically used to identify prodromal stages of dementia, it is essential to identify MCI criteria with high diagnostic stability and prediction of dementia. Moreover, further investigation into pinpointing key factors for reversion is required to foresee future prognosis of MCI patients accurately.

OBJECTIVE

To explore disparities in diagnostic stability by examining reversion rates produced by two operationalizations of the MCI definition: the widely applied Petersen criteria and a version of the Neuropsychological (NP) criteria and to identify cognitive, lifestyle, and health related factors for reversion.

METHODS

MCI was retrospectively classified in a sample from the Swedish community-based study Good Aging in Skåne with the Petersen criteria (n = 744, median follow-up = 7.0 years) and the NP criteria (n = 375, median follow-up, 6.7 years), respectively. Poisson regression models estimated the effect of various factors on the likelihood of incident reversion.

RESULTS

Reversion rates were 323/744 (43.4%, 95% confidence intervals (CI): 39.8; 47.0) and 181/375 (48.3% 95% CI: 43.2; 53.5) for the Petersen criteria and NP criteria, respectively. Participants with impairment in a single cognitive domain, regular alcohol consumption, living with someone, older age, and lower body mass index had a higher likelihood of reverting to normal.

CONCLUSION

Reversion rates were similar for Petersen and NP criteria indicating that one definition is not superior to the other regarding diagnostic stability. Additionally, the results highlight important aspects such as multiple domain MCI, cohabitation, and the role of alcohol on predicting the trajectory of those diagnosed with MCI.

R4Alz-Revised: A Tool Able to Strongly Discriminate 'Subjective Cognitive Decline' from Healthy Cognition and 'Minor Neurocognitive Disorder'

BACKGROUND

The diagnosis of the minor neurocognitive diseases in the clinical course of dementia before the clinical symptoms' appearance is the holy grail of neuropsychological research. The R4Alz battery is a novel and valid tool that was designed to assess cognitive control in people with minor cognitive disorders. The aim of the current study is the R4Alz battery's extension (namely R4Alz-R), enhanced by the design and administration of extra episodic memory tasks, as well as extra cognitive control tasks, towards improving the overall R4Alz discriminant validity.

METHODS

The study comprised 80 people: (a) 20 Healthy adults (HC), (b) 29 people with Subjective Cognitive Decline (SCD), and (c) 31 people with Mild Cognitive Impairment (MCI). The groups differed in age and educational level.

RESULTS

Updating, inhibition, attention switching, and cognitive flexibility tasks discriminated SCD from HC (p ≤ 0.003). Updating, switching, cognitive flexibility, and episodic memory tasks discriminated SCD from MCI (p ≤ 0.001). All the R4Alz-R's tasks discriminated HC from MCI (p ≤ 0.001). The R4Alz-R was free of age and educational level effects. The battery discriminated perfectly SCD from HC and HC from MCI (100% sensitivity-95% specificity and 100% sensitivity-90% specificity, respectively), whilst it discriminated excellently SCD from MCI (90.3% sensitivity-82.8% specificity).

CONCLUSION

SCD seems to be stage a of neurodegeneration since it can be objectively evaluated via the R4Alz-R battery, which seems to be a useful tool for early diagnosis.

The impact of mild cognitive impairment on decision-making under explicit risk conditions: Evidence from the Personality and Total Health (PATH) Through Life longitudinal study

OBJECTIVE

Previous research has indicated that cognition and executive function are associated with decision-making, however the impact of mild cognitive impairment (MCI) on decision-making under explicit risk conditions is unclear. This cross-sectional study examined the impact of MCI, and MCI subtypes, on decision-making on the Game of Dice Task (GDT), among a cohort of older adults.

METHOD

Data from 245 older adult participants (aged 72-78 years) from the fourth assessment of the Personality and Total Health Through Life study were analyzed. A diagnostic algorithm identified 103 participants with MCI, with subtypes of single-domain amnestic MCI (aMCI-single; n = 38), multi-domain amnestic MCI (aMCI-multi; n = 31), and non-amnestic MCI (n = 33), who were compared with an age-, sex-, education-, and income-matched sample of 142 cognitively unimpaired older adults. Decision-making scores on the GDT (net score, single number choices, and strategy changes) were compared between groups using nonparametric tests.

RESULTS

Participants with MCI showed impaired performance on the GDT, with higher frequencies of single number choices and strategy changes. Analyses comparing MCI subtypes indicated that the aMCI-multi subtype showed increased frequency of single number choices compared to cognitively unimpaired participants. Across the sample of participants, decision-making scores were associated with measures of executive function (cognitive flexibility and set shifting).

CONCLUSION

MCI is associated with impaired decision-making performance under explicit risk conditions. Participants with impairments in multiple domains of cognition showed the clearest impairments. The GDT may have utility in discriminating between MCI subtypes.

Working memory assessment using cambridge neuropsychological test automated battery can help in the diagnosis of mild cognitive impairment: a systematic review and meta-analysis

ABSTRACT Mild cognitive impairment (MCI) is an interstitial state between normal aging and dementia. Objective: In this study, we investigated working memory (WM) profiles of MCI patients using the Cambridge Neuropsychological Test Automated Battery (CANTAB). We also examined the diagnostic accuracy and possible associated factors as secondary outcomes of the study. Methods: We conducted an electronic search on EMBASE, PubMed, and ScienceDirect databases. Studies with MCI participants and using CANTAB battery subtests for the assessment of WM were included. Meta-analysis was conducted using the CMA2 software. Results: Out of 1537 records, 14 studies were covered in this systematic review, and 7 of them were included in the meta-analysis. There was a significant difference between MCI patients and healthy controls in spatial working memory (SWM) (SDM: 0.535; 95%CI 11–96; p-value=0.014), spatial span (SSP) (SDM: 0.649 95%CI 0.297–0.100; p-value<0.01), and rapid visual information processing (RVP) (SDM: 0.52; 95%CI 0.386–0.654; p-value<0.01). WM function of MCI patients was associated with the cerebrospinal fluid (CSF) levels of tau-protein and amyloid-beta (Aβ). Conclusions: WM is an impaired cognitive domain in MCI. CANTAB WM subtests including SSP, SWM, and RVP are accurate enough to be used as a proper assessment tool for the diagnosis of MCI in clinical settings. Tau-protein and Aβ are associated with lower WM scores in MCI patients; however, sex, age, psychiatric disorders, apolipoprotein 4 allele, and functional activity scores cannot affect WM.

Fronto-temporal functional disconnection precedes hippocampal atrophy in clinically confirmed multi-domain amnestic Mild Cognitive Impairment

Mild Cognitive Impairment (MCI) is fraught with high false positive diagnostic errors. The high rate of false positive diagnosis hampers attempts to identify reliable and valid biomarkers for MCI. Recent research suggests that aberrant functional neurocircuitries emerge prior to significant cognitive deficits. The aim of the present study was to examine this in clinically confirmed multi-domain amnestic-MCI (mdaMCI) using an established, multi-time point, methodology for minimizing false positive diagnosis. Structural and resting-state functional MRI data were acquired in healthy controls (HC, n=24), clinically-confirmed multi-domain amnestic-MCI (mdaMCI, n=14) and mild Alzheimer's Dementia (mAD, n=6). Group differences in cortical thickness, hippocampal volume and functional connectivity were investigated. Hippocampal subvolumes differentiated mAD from HC and mdaMCI. Functional decoupling of fronto-temporal networks implicated in memory and executive function differentiated HC and mdaMCI. Decreased functional connectivity in these networks was associated with poorer cognitive performance scores. Preliminary findings suggest the large-scale decoupling of fronto-temporal networks associated with cognitive decline precedes measurable structural neurodegeneration in clinically confirmed MCI and may represent a potential biomarker for disease progression.

The My Active and Healthy Aging ICT platform prevents quality of life decline in older adults: a randomised controlled study

INTRODUCTION

Prevention of frailty is paramount in older adults. We evaluated the efficacy of a tailored multidomain intervention, monitored with the My Active and Healthy Aging platform, in reducing conversion from a prefrail status to overt frailty and preventing decline in quality of life.

METHODS

We performed a multicentre, multicultural, randomised control study. The effects of multidomain interventions on frailty parameters, quality of life, physical, cognitive, psychosocial function, nutrition and sleep were evaluated in a group of 101 prefrail older subjects and compared with 100 prefrail controls, receiving general health advice.

RESULTS

At the 12-month assessment, controls showed a decline in quality of life that was absent in the active group. In addition, active participants showed an increase in mood and nutrition function. No effect on remaining parameter was observed.

DISCUSSION

Our study supports the use of personalised multidomain intervention, monitored with an information and communication technology platform, in preventing quality of life decline in older adults.

Predementia constructs: Mild cognitive impairment or mild neurocognitive disorder? A narrative review

BACKGROUND

Predementia is a heuristic umbrella concept to classify older adults with cognitive impairment who do not suffer dementia. Many diagnostic entities have been proposed to address this concept, but most of them have not had widespread acceptance.

AIMS

To review clinical definitions, epidemiologic data (prevalence, incidence) and rate of conversion to dementia of the main predementia constructs, with special interest in the two most frequently used: mild cognitive impairment (MCI) and minor neurocognitive disorder (miNCD).

METHODS

We have selected in three databases (MEDLINE, Web of Science and Google scholar) the references from inception to 31 December 2019 of relevant reviews, population and community-based surveys, and clinical series with >500 participants and >3 years follow-up as the best source of evidence.

MAIN RESULTS

The history of predementia constructs shows that MCI is the most referred entity. It is widely recognized as a clinical syndrome harbinger of dementia of several etiologies, mainly MCI due to Alzheimer's disease. The operational definition of MCI has shortcomings: vagueness of its requirement of "preserved independence in functional abilities" and others. The recent miNCD construct presents analogous difficulties. Current data indicate that it is a stricter predementia condition, with lower prevalence than MCI, less sensitivity to cognitive decline and, possibly, higher conversion rate to dementia.

CONCLUSIONS

MCI is a widely employed research and clinical entity. Preliminary data indicate that the clinical use of miNCD instead of MCI requires more scientific evidence. Both approaches have common limitations that need to be addressed.

Using an Overlapping Time Interval Strategy to Study Diagnostic Instability in Mild Cognitive Impairment Subtypes

(1) Background: Mild cognitive impairment (MCI) is a diagnostic label in which stability is typically low. The aim of this study was to examine temporal changes in the diagnosis of MCI subtypes by using an overlapping-time strategy; (2) Methods: The study included 435 participants aged over 50 years with subjective cognitive complaints and who completed at least one follow-up evaluation. The probability of transition was estimated using Bayesian odds ratios; (3) Results: Within the different time intervals, the controls with subjective cognitive complaints represented the largest proportion of participants, followed by sda-MCI at baseline and in the first five intervals of the follow-up, but not in the last eight intervals. The odds ratios indicated higher odds of conversion to dementia in sda-MCI and mda-MCI groups relative to na-MCI (e.g., interval 9–15 months—sda-MCI OR = 9 and mda-MCI OR = 3.36; interval 27–33—sda-MCI OR = 16 and mda-MCI = 5.06; interval 42–48—sda-MCI OR = 8.16 and mda-MCI = 3.45; interval 45–51—sda-MCI OR = 3.31 and mda-MCI = 1); (4) Conclusions: Notable patterns of instability consistent with the current literature were observed. The limitations of a prospective approach in the study of MCI transitions are discussed.

Cognitive tests for the detection of mild cognitive impairment (MCI), the prodromal stage of dementia: Meta-analysis of diagnostic accuracy studies

INTRODUCTION

Mild cognitive impairment (MCI) is regarded as a prodrome to dementia. Various cognitive tests can help with diagnosis; meta-analysis of diagnostic accuracy studies would assist clinicians in choosing optimal tests.

METHODS

We searched online databases for "mild cognitive impairment" and "diagnosis" or "screening" from 01/01/1999 to 01/07/2017. Articles assessing the diagnostic accuracy of a cognitive test compared with standard diagnostic criteria were extracted. Risk of bias was assessed. Bivariate random-effects meta-analysis was used to evaluate sensitivity and specificity.

RESULTS

Eight cognitive tests (ACE-R, CERAD, CDT-Sunderland, IQCODE, Memory Alteration Test, MMSE, MoCA, and Qmci) were considered for meta-analysis. ACE-R, CERAD, MoCA, and Qmci were found to have similar diagnostic accuracy, while the MMSE had lower sensitivity. Memory Alteration Test had the highest sensitivity and equivalent specificity to the other tests.

DISCUSSION

Multiple cognitive tests have comparable diagnostic accuracy. The Memory Alteration Test is short and has the highest sensitivity. New cognitive tests for MCI diagnosis should not be compared with the MMSE.

Spatial reorientation decline in aging: the combination of geometry and landmarks

OBJECTIVES

The study is focused on the assessment of reorientation skills in a sample of community-dwelling elderly people, manipulating landmarks and geometric (layout) information.

METHOD

A neuropsychological assessment was administered to 286 elderly participants, divided into six groups (healthy controls, HC; four subgroups of participants with mild cognitive impairment, MCI; participants with probable dementia, Prob_D) and tested with the Virtual Reorientation Test (VReoT). VReoT manipulated different spatial cues: geometry and landmarks (proximal and distal).

RESULT

Compared with HC, participants with MCI and Prob_D showed to be impaired in tasks involving geometry, landmarks and a combination of them. Both single and multiple domain impairment in MCI had an impact on reorientation performance. Moreover, VReoT was marginally able to discriminate between amnesic and non-amnesic MCI. The occurrence of getting lost events seemed to be associated to learning of geometric information.

CONCLUSION

The associative strength between landmark and target plays an important role in affecting spatial orientation performance of cognitively impaired participants. Geometry significantly supports landmark information and becomes helpful with the increase of cognitive impairment which is linked to a decrement in landmark encoding. VReoT seems to represent a reliable evaluation supplement for spatial orientation deficits in prodromal stages of dementia.

Prognostic Significance of Mild Cognitive Impairment Subtypes for Dementia and Mortality: Data from the NEDICES Cohort

BACKGROUND

The predictive value of diverse subtypes of mild cognitive impairment (MCI) for dementia and death is highly variable.

OBJECTIVE

To compare the predictive value of several MCI subtypes in progression to dementia and/or mortality in the NEDICES (Neurological Disorders in Central Spain) elderly cohort.

METHODS

Retrospect algorithmic MCI subgroups were established in a non-dementia baseline NEDICES cohort using Spanish adaptations of the original Mini-Mental State Examination (MMSE-37) and Pfeffer's Functional Activities Questionnaire (Pfeffer-11). The presence of MCI was defined according two cognitive criteria: using two cut-offs points on the total MMSE-37 score. Five cognitive domains were used to establish the MCI subtypes. Functional capacity (Pfeffer-11) was preserved or minimally impaired in all MCI participants. The incident dementia diagnoses were established by specialists and the mortality data obtained from Spanish official registries.

RESULTS

3,411 participants without dementia were assessed in 1994-5. The baseline prevalence of MCI varied according to the MCI definition (4.3%-31.8%). The follow-up was a mean of 3.2 years (1997-8). The dementia incidence varied between 14.9 and 71.8 per 1,000/person-years. The dementia conversion rate was increased in almost all MCI subgroups (p >  0.01), and mortality rate was raised only in four MCI subtypes. The amnestic-multi-domain MCI (aMd-MCI) had the best dementia predictive accuracy (highest positive likelihood ratio and highest clinical utility when negative).

CONCLUSIONS

Those with aMd-MCI were at greatest risk of progression to dementia, as in other surveys and might be explored with increased attention in MCI research and in dementia preventive trials.

A randomised control trial of the cognitive effects of working in a seated as opposed to a standing position in office workers

Sedentary behaviour is increasing and has been identified as a potential significant health risk, particularly for desk-based employees. The development of sit-stand workstations in the workplace is one approach to reduce sedentary behaviour. However, there is uncertainty about the effects of sit-stand workstations on cognitive functioning. A sample of 36 university staff participated in a within-subjects randomised control trial examining the effect of sitting vs. standing for one hour per day for five consecutive days on attention, information processing speed, short-term memory, working memory and task efficiency. The results of the study showed no statistically significant difference in cognitive performance or work efficiency between the sitting and standing conditions, with all effect sizes being small to very small (all ds < .2). This result suggests that the use of sit-stand workstations is not associated with a reduction in cognitive performance. Practitioner Summary: Although it has been reported that the use of sit-stand desks may help offset adverse health effects of prolonged sitting, there is scant evidence about changes in productivity. This randomised control study showed that there was no difference between sitting and standing for one hour on cognitive function or task efficiency in university staff.

Relation between subcortical grey matter atrophy and conversion from mild cognitive impairment to Alzheimer's disease

OBJECTIVE

To investigate whether subcortical grey matter atrophy predicts progression from mild cognitive impairment (MCI) to Alzheimer's disease (AD), and to compare subcortical volumes between AD, MCI and controls. To assess the correlation between subcortical grey matter volumes and severity of cognitive impairment.

METHODS

We included 773 participants with three-dimensional T1-weighted MRI at 3 T, made up of 181 controls, who had subjective memory symptoms with normal cognition, 201 MCIs and 391 AD. During follow-up (2.0 ± 0.9 years), 35 MCIs converted to AD (progressive MCI) and 160 MCIs remained stable (stable MCI). We segmented volumes of six subcortical structures of the amygdala, thalamus, caudate nucleus, putamen, globus pallidus and nucleus accumbens, and of the hippocampus, using FMRIBs integrated registration and segmentation tool.

RESULTS

Analysis of variances, adjusted for sex and age, showed that all structures, except the globus pallidus, were smaller in AD than in controls. In addition, the amygdala, thalamus, putamen, nucleus accumbens and hippocampus were smaller in MCIs than in controls. Across groups, all subcortical greymatter volumes, except the globus pallidus, showed a positive correlation with cognitive function, as measured by Mini Mental State Examination (MMSE) (0.16<r<0.28, all p<0.05). Cox proportional hazards analyses adjusted for age, sex, education, Cambridge Cognitive Examination-Revised (CAMCOG-R) and MMSE showed that smaller volumes of the hippocampus and nucleus accumbens were associated with increased risk of progression from MCI to AD (HR (95% CI) 1.60 (1.15 to 2.21); 1.60 (1.09 to 2.35), p<0.05).

CONCLUSIONS

In addition to the hippocampus, the nucleus accumbens volume loss was also associated with increased risk of progression from MCI to AD. Furthermore, volume loss of subcortical grey matter structures was associated with severity of cognitive impairment.