Current evidence for subjective cognitive impairment (SCI) as the pre-mild cognitive impairment (MCI) stage of subsequently manifest Alzheimer's disease

Associations of Lipophilic Micronutrients with Physical and Cognitive Fitness in Persons with Mild Cognitive Impairment

Age-associated cognitive impairment in general and dementia in particular are a global concern. Preventive lifestyle strategies are highly used but there is a lack of information on the reciprocal relationships between nutrition biomarkers and measures of both cognitive and physical performance. To fill this gap of knowledge, the relationship between plasma levels of the robust nutrition- and antioxidant defense-related biomarkers carotenoid and tocopherols and both indicators of cognitive and physical performance was investigated in a group of persons with mild cognitive impairment participating in the NeuroExercise Study at the German Sport University in Cologne, Germany. In 56 participants with full dataset, significant correlations independently of fruit and vegetable intake were found between plasma levels of β-cryptoxanthin and Timed Up&Go test (p < 0.05), γ-tocopherol and number of daily steps (p < 0.01), as well as between four out of six measured carotenoids—lutein; zeaxanthin; β-cryptoxanthin and β-carotene—and the computerized CogState International Shopping List subtest (p < 0.01). In light of the increasing attention towards the nutritional cognitive neuroscience of carotenoids, computerized measures of cognitive performance might be further implemented in future studies investigating the effects of lifestyle interventions against cognitive and physical impairment.

Subjective ratings of cognitive and emotional functioning in patients with mild cognitive impairment and patients with subjective memory complaints but normal cognitive functioning

In a retrospective chart review, 39 patients referred for a clinical neuropsychological examination were identified as showing either mild cognitive impairment of the amnestic type (MCI-A; N = 21) or subjective memory complaints but with normal memory function (SMC; N = 18). During the clinical interview, patients and informants were routinely asked to make subjective ratings regarding the patient's cognitive and affective functioning in everyday life. The purpose of this study was to determine whether these two patient groups (and their informants) significantly differed in their subjective reports about level of cognitive and affective difficulties. It was predicted that SMC patients would report higher levels of cognitive and emotional dysfunction than MCI-A patients. It was further predicted that MCI-A patients would underreport cognitive difficulties (compared to informant reports); SMC patients would demonstrate the opposite pattern. Results supported these predictions and suggest that routine assessment of subjective experiences of patients in conjunction with informant ratings may aid clinical diagnosis, particularly when the primary complaint is a decline in memory.

The dual role of cognitive reserve in subjective cognitive decline and mild cognitive impairment: a 7-year follow-up study

The aim of this study was to evaluate the effect of cognitive reserve (CR), in progression from subjective cognitive decline (SCD) to mild cognitive impairment (MCI) and Alzheimer's disease (AD). For this purpose, we followed up 263 patients (154 SCD; 109 MCI) for a mean time of 7 years. CR was assessed by the Test di Intelligenza Breve (TIB), functionally equivalent to the National Adult Reading Test. High CR resulted as a protective factor for progression from SCD to MCI. Age at conversion to MCI was delayed 9 years on average in SCD with high CR with respect to SCD with low CR. On the contrary, high CR resulted as a risk factor for progression from MCI to AD dementia only in APOE ε4 carriers. Conversion time from MCI to AD dementia was 3 years shorter in ε4 carriers with high CR than subjects with low CR and ε4 non-carriers with high CR. Consistent with the CR hypothesis, our results showed that higher levels of CR protect against the earliest clinical manifestations of AD. In line with the previous researches, we found an interaction between CR and APOE in progression from MCI to AD dementia.

Two Year Outcomes, Cognitive and Behavioral Markers of Decline in Healthy, Cognitively Normal Older Persons with Global Deterioration Scale Stage 2 (Subjective Cognitive Decline with Impairment)

BACKGROUND

Little is known with respect to behavioral markers of subjective cognitive decline (SCD), a condition initially described in association with Global Deterioration Scale (GDS) stage 2.

OBJECTIVE

Two-year interval behavioral markers were investigated herein.

METHODS

Subjects from a published 7-year outcome study of GDS stage 2 subjects were selected. This study had demonstrated a hazard ratio of 4.5 for progression of GDS stage 2, in comparison with GDS stage 1 (no subjective or objective cognitive decline) subjects, after controlling for demographic and temporal variables. Because GDS 2 subjects have previously demonstrated impairment in comparison with healthy persons free of complaints, we herein suggest the terminology "SCD(I)" for these persons. 98 SCD(I) persons, 63 women and 35 men, mean baseline age, 67.12±8.75 years, with a mean educational background of 15.55±2.60 years, and mean baseline MMSE scores of 28.9±1.24 were followed for 2.13±0.30 years.

RESULTS

Observed annual decline on the GDS was 6.701% per annum, very close to a 1986 published estimate. At follow up, the MMSE, and 7 of 8 psychometric tests did not decline significantly. Of 21 Hamilton Depression Scale items, 2 improved and the remainder were unchanged. Anxieties declined from multiple perspectives. The Brief Cognitive Rating Scale (BCRS) declined significantly (p < 0.001), with component declines in Remote memory (p < 0.01), and Functioning/self-care (p = 0.01).

CONCLUSION

SCD(I) persons decline at an annual rate of approximately 6.7% /year from several recent studies. The BCRS assessments and the Digit Symbol Substitution Test can be sensitive measures for future studies of progression mitigation.

Alterations in structural rich-club connectivity of the precuneus are associated with depressive symptoms among individuals with subjective memory complaints

The association between subjective memory complaints (SMCs) and depressive symptoms has been widely reported and both have been regarded as risk factors for dementia, such as Alzheimer's disease (AD). Although SMCs arise as early as in middle age, the exact neural correlates of comorbid depressive symptoms among individuals who are middle-aged and with SMCs have not yet been well investigated. Because rich-club organization of the brain plays a key role in the pathophysiology of various neuropsychiatric disorders, the investigation of rich club organization may provide insight regarding the neurobiological mechanisms of depressive symptoms in SMCs. In the current study, we compared the rich-club organization in the structural brain connectivity between individuals who have SMCs along with depressive symptoms (SMCD) and individuals with SMCs but without depressive symptoms (SMCO). A total of 53 individuals with SMCD and 91 individuals with SMCO participated in the study. For all participants, high-resolution, T1-weighted images and diffusion tensor images were obtained, and the network analysis was performed. Individuals with SMCD had lower connectivity strength between the precuneus and other rich-club nodes than those with SMCO, which was significant after adjusting for potential confounders. Our findings suggest that disruptions of rich-club connectivity strength of the precuenus are associated with depressive symptoms in middle-aged individuals with SMCs. Given that the precuneus is one of the commonly affected regions in the early stages of AD, our findings may imply that the concomitant depressive symptoms in middle-aged individuals with SMCs could reflect structural alterations related to AD.

Aiding medical professionals in fitness-to-drive screenings for elderly drivers: development of an office-based screening tool

ABSTRACTBackground:Elderly drivers are an increasing group in society. Previous research has found that functional and cognitive abilities are more important for driving abilities than biological age. In an attempt to conserve independent mobility for elderly drivers, many researchers have focused on elderly drivers diagnosed with cognitive decline (mild cognitive impairment or mild Dementia). This study is the first to focus on elderly drivers with cognitive complaints or suspected of diminished fitness to drive by an (in)formal caregiver as an at-risk group.

METHODS

The main objective of this study was to develop a fitness to drive screening tool for elderly drivers to be used in a doctor's office. Furthermore, this study investigated the additional value of driving simulator tests in the assessment of fitness to drive. Both screenings (functional abilities and driving simulator test) were benchmarked against the official Belgian fitness to drive licensing procedure.

RESULTS

One-hundred thirty-six elderly drivers participated in a functional abilities screening, a driving simulator assessment and an on-road driving test. Sixty-five percent of the sample was considered fit to drive. Visual acuity, physical flexibility, and knowledge of road signs were found to be the best predictive set of tests for the on-road fitness to drive outcome. A performance based driving simulator assessment increased predictive accuracy significantly.

CONCLUSION

The proposed screening procedure saves part of the at-risk elderly driver population from stressful and costly on-road driving evaluations. This procedure provides more information of an individual driver's specific driving parameters. This opens doors for personalized older driver training to maintain independent mobility in later life.

Effects of Cognitive Reserve on Cognitive Performance in a Follow-Up Study in Older Adults With Subjective Cognitive Complaints. The Role of Working Memory

Objective: Analyze the effects of CR on cognitive performance in adults with subjective cognitive complaints at follow-up. Method: We analyzed the factorial structure of the three constructs defined in cognitive performance (Episodic memory, Working memory, and General cognitive performance) separately to search for evidence of the invariance of the measurement model. We then developed four structural nested models to analyze the relationship between CR and cognitive performance, measured at baseline and after approximately 18 months, in 266 participants older than 50 years with subjective cognitive complaints. Results: The nested models revealed the following main results: direct effects of CR on all cognitive constructs at baseline and also indirect effects on the same constructs at follow-up, and indirect effects of CR on other cognitive constructs at follow-up via working memory at follow-up. Conclusion: The findings show that the proposed model is useful for measuring the influence of CR on cognitive performance in follow-up studies and that CR has a positive influence on cognitive performance at follow-up via working memory. CR may enhance mechanisms of information processing, favoring performance of tasks involving other cognitive constructs in older adults with subjective cognitive complaints.

Different Cognitive Complaint Profiles in Memory Clinic and Depressive Patients

OBJECTIVE

Cognitive complaints are considered early indicators of incipient Alzheimer's disease (AD) but are very common in geriatric patients, especially in patients with major depressive disorder (MDD). The clinical assessment of cognitive complaints is still poorly operationalized. Recent qualitative research suggests that certain phenomenologic complaint themes may have some specificity for prodromal AD. The aim of the study was to replicate and explore their occurrence in a clinical setting.

METHODS

In a cross-sectional, case-control study using a mixed-methods approach, 23 memory clinic (cognitive complainers [CC]) patients, 21 psychiatric inpatients with MDD, and 21 healthy control subjects, aged 55-86 years, were assessed at the Department of Psychiatry and Psychotherapy and German Center for Neurodegenerative Diseases, Bonn. A newly developed semistructured interview addressing 12 complaint themes was used, and transcribed open format responses were coded by qualitative expert rating (theme absent versus present) and compared between the groups.

RESULTS

Seven complaint themes (e.g., sense of predomination, progression) were significantly more often endorsed by the CC group, together with a novel theme of "distractible speech." Complaint themes in those with depression aligned with the depressive symptoms and appeared to be partly different from the complaint pattern of the CC group.

CONCLUSION

Previously established themes were found to be feasible for conversion into a semistructured interview. Several complaint phenotypes were confirmed and previous themes significantly expanded by providing first evidence for a qualitatively different complaint profile in MDD compared with CC. Future investigations may benefit from better characterizing the phenomenologic and qualitative characteristics of AD-related complaints.

Subjective Cognitive Decline Modifies the Relationship Between Cerebral Blood Flow and Memory Function in Cognitively Normal Older Adults

OBJECTIVES

Subjective cognitive decline (SCD), or self-reported cognitive decline despite normal neuropsychological test performance, is a risk factor for objective cognitive decline and Alzheimer's disease (AD). While brain mechanisms contributing to SCD are not well defined, studies show associations with vascular risk factors and altered cerebral blood flow (CBF), raising the hypothesis that those with SCD might be experiencing vascular dysregulation, or a disruption in the normal relationship between CBF and cognition. We examined whether the association between CBF and verbal memory performance differs between those with SCD (SCD+) and those without SCD (SCD-).

METHODS

Linear mixed-effects models were used to investigate whether the voxel-wise relationship between arterial spin labeling (ASL) MRI-measured CBF and verbal memory performance was modified by SCD among a group of 70 cognitively normal older adults (35 SCD+, 35 SCD-; mean age=72) matched on age, gender, and symptoms of depression.

RESULTS

Results indicated that the SCD- group exhibited positive associations between verbal memory and CBF within the posterior cingulate cortex, middle temporal gyrus, and inferior frontal gyrus, whereas the SCD+ group displayed negative associations between verbal memory and CBF within the posterior cingulate cortex, middle temporal gyrus, hippocampus, fusiform gyrus, and inferior frontal gyrus.

CONCLUSIONS

Findings suggest that, while higher CBF is supportive of memory function in those without SCD, higher CBF may no longer support memory function in those presenting with SCD, perhaps reflecting neurovascular dysregulation. (JINS, 2018, 24, 213-223).

Social inappropriateness in neurodegenerative disorders

BACKGROUND

New onset of mood and behavioral changes in middle-aged patients are frequently the first manifestations of an unrecognized neurocognitive disorder. Impairment of social cognition, the cognitive ability to process social information coming from others, such as emotions, to attribute mental states to others, and to respond appropriately to them, is often at the origin of behavioral manifestations in neurodegenerative disorders.

METHODS

This paper reviews the current literature on social cognition impairment in neurocognitive disorders, particularly in prodromal stages of behavioral-variant frontotemporal dementia (bvFTD), Alzheimer's disease (AD), idiopathic Parkinson's disease (IPD), and Lewy body dementia (LBD). The concepts of social cognition will be reviewed, including its impairment and neural basis, its clinical assessment, and the different therapeutic interventions available clinically.

RESULTS

Socially inappropriate behaviors, such as loss of empathy, inappropriateness of affect, and disinhibition are frequently reported in prodromal bvFTD and in prodromal AD. Lack of self-control, reduced perception of social cues, such as recognition of facial emotions and sarcastic speech, and impaired Theory of Mind all contribute to the neuropsychiatric symptoms and are secondary to neurodegeneration in specific brain regions. In contrasts to bvFTD and AD, deficits in social cognition in IPD occur later in the course of the disease and are often multifactorial in origin.

CONCLUSIONS

Through various manifestations, social inappropriateness is frequently the first clinical sign of a neurodegenerative process, especially in AD and bvFTD, years before noticeable impairment on classical neuropsychological assessment and brain atrophy on imaging.

The Clock Drawing Test versus Mini-mental Status Examination as a Screening Tool for Dementia: A Clinical Comparison

There is a growing incidence of dementia patients in the community, and with this growth, there is need for rapid, valid, and easily administrable tests for the screening of dementia and mild cognitive impairment in the community. This review looks at the two most commonly used tests in dementia screening, namely, the clock drawing test (CDT) and the mini-mental status examination (MMSE). Both these tests have been used in dementia screening over the past three decades and have been the subject of scrutiny of various studies, reviews, and meta-analysis. Both these tests are analyzed on their ability to assess dementia and screen for it in the community, general practice and general hospital settings. The methods of administration and scoring of each test are discussed, and their advantages and disadvantages are explained. There is also a direct comparison made between the MMSE and CDT in dementia screening. Future research needs with these tests are also elucidated.

Characteristics of Healthy Older Adults that Influence Self-rated Cognitive Function

OBJECTIVES

We sought to clarify the nature of self-reported cognitive function among healthy older adults by considering the short-term, within-person association (coupling) of subjective cognitive function with objective cognitive performance. We expected this within-person coupling to differ between persons as a function of self-perceived global cognitive decline and depression, anxiety, or neuroticism.

METHODS

This was an intensive measurement (short-term longitudinal) study of 29 older adult volunteers between the ages of 65 and 80 years without an existing diagnosis of dementia or mild cognitive impairment. Baseline assessment included neuropsychological testing and self-reported depression, anxiety, and neuroticism, as well as self- and informant-reported cognitive decline (relative to 10 years previously). Intensive within-person measurement occasions included subjective ratings of cognitive function paired with performance on a computerized working memory (n-back) task; each participant attended four or five assessments separated by intervals of at least one day. Statistical analysis was comprised of multilevel linear regression.

RESULTS

Comparison of models suggested that both neuroticism and self-rated cognitive decline explained unique variance in the within-person, across-occasion coupling of subjective cognitive function with objective working memory performance.

CONCLUSIONS

Self-ratings of cognition may accurately reflect day-to-day variations in objective cognitive performance among older adults, especially for individuals lower in neuroticism and higher in self-reported cognitive decline. Clinicians should consider these individual differences when determining the validity of complaints about perceived cognitive declines in the context of otherwise healthy aging. (JINS, 2018, 24, 57-66).

Subjective memory complaint as a useful tool for the early detection of Alzheimer's disease

PURPOSE

Despite their high prevalence in Alzheimer's disease (AD), and the increasing level of concern they have generated, subjective memory complaints (SMCs) are poorly understood. This study investigated the accuracy with which SMC can separate mild cognitive impairment (MCI) and early AD from cognitive normal (CN), and explored whether the discrimination ability is similar to or better than that of the Mini-Mental State Exam (MMSE).

PATIENTS AND METHODS

This study recruited 175 CN subjects, 52 with MCI, and 66 with probable AD aged 60 years or older. To test the independent contributions of SMC and MMSE scores to the classification of cognitive status (CN vs MCI or early AD), logistic regression analyses were performed, adjusting for the following potential confounding variables: age, gender, Frontal Assessment Battery score, modified Hachinski Ischemic Scale score, and apolipoprotein E ε4 status. Receiver operating characteristic (ROC) curve analyses were used to determine the discrimination accuracy of SMC and MMSE scores, and area under the ROC curve (AUROC) was also calculated.

RESULTS

In the highly educated (≥7 years), nondepressed (Geriatric Depression Scale ≤15) subgroup, SMC showed good accuracy in discriminating cognitively impaired subjects from CN after adjusting for potential confounding variables (the AUROC of the adjusted SMC was 0.841 for MCI discrimination, and it was 0.858 for MCI plus early AD discrimination). Both SMC and MMSE scores significantly contributed to differentiating between CN and MCI (OR=2.372, 95% CI=1.086-5.177; OR=0.730, 95% CI=0.566-0.941, respectively) after adjusting for the same covariates. However, in the highly educated and nondepressed subgroups, SMC showed significant predictive power for MCI from CN (OR=3.119, 95% CI=1.190-8.176; OR=3.328, 95% CI=1.320-8.396, respectively), whereas MMSE scores did not.

CONCLUSION

Our findings support the usefulness of SMC, which was comparable or even superior to MMSE scores, for detecting MCI or early AD.

The Worried Well? Characteristics of Cognitively Normal Patients Presenting to a Rural and Remote Memory Clinic

INTRODUCTION

In an effort to better understand why cognitively normal patients were referred to a memory clinic, we sought to identify features of "worried well" patients to better identify those more likely to be cognitively normal.

METHODS

In total, 375 consecutive patients referred by primary care practitioners to a Rural and Remote Memory Clinic were categorized into two groups based on their neurologic diagnosis, "worried well" (cognitively normal, N=81) or "other" (patients with any neurologic diagnosis, N=294). Data collected included: age, sex, years of formal education, Mini-Mental Status Examination score from initial visit, Center for Epidemiologic Studies Depression Scale score, Self-Rating of Memory Scale, alcohol consumption, marital status, hours per week of work, past medical history, sleep concerns, and family history of memory concerns. The two groups were compared using t-tests and χ2 tests. The same comparison was done between the same set of "worried well" patients (cognitively normal, N=81) and the subgroup of patients with a diagnosis of Alzheimer's disease (N=146) from the "other" group.

RESULTS

Significant differences included younger age, more formal education, more frequently having previous psychiatric diagnosis and more self-reported alcohol consumption in the "worried well" group. The "worried well" and "Alzheimer's disease" comparison had the same significant differences as the "worried well" and "other" comparison.

CONCLUSION

We observed a pattern of differences unfold between the "worried well" patients and those with cognitive disease. No one variable was pathognomonic of a "worried well" patient. However, taking all the above into account when evaluating a patient may help clinically.

Neuropsychological Profiles in Mild Cognitive Impairment due to Alzheimer's and Parkinson's Diseases

Background: Neuropsychological comparisons between patients with mild cognitive impairment due to Parkinson’s disease (MCI-PD) and Alzheimer’s disease (MCI-AD) is mostly based on indirect comparison of patients with these disorders and normal controls (NC).

Objective: The focus of this study was to make a direct comparison between patients with these diseases.

Methods: The study compared 13 patients with MCI-PD and 19 patients with MCI-AD with similar age, education and gender. The participants were recruited and assessed at the same university clinic with equal methods.

Results: The main finding was that on group level, MCI-AD scored significantly poorer on learning and memory tests than MCI-PD, whereas MCI-PD were impaired on 1 of 3 measures of executive functioning.

Conclusion: MCI-AD performed poorer learning and memory tests, whereas MCI-PD only scored below the employed cut-off on one single executive test. In general, MCI-PD was noticeably less cognitively impaired than MCI-AD.

Twelve-Week Exercise Influences Memory Complaint but not Memory Performance in Older Adults: A Randomized Controlled Study

This study aimed to evaluate the effects of different types of exercise on memory performance and memory complaint after a 12-week intervention. Eighty community-dwelling volunteers, aged 66.96 ± 11.73 years, were randomly divided into four groups: resistance, cardiovascular, postural, and control groups (20 participants for each group). All participants were tested for their cognitive functions before and after their respective 12-week intervention using Rey memory words test, Prose memory test, and Memory Complaint Questionnaire (MAC-Q). Statistical analysis showed that the three experimental groups significantly improved MAC-Q scores in comparison with the control group (p < .05). The variation of MAC-Q scores and the variations of Rey and Prose memory tests scores were not correlated. These results indicate that the 12-week interventions exclusively influenced memory complaint but not memory performance. Further investigations are needed to understand the relation between memory complaint and memory performance, and the factors that can influence this relationship.

Tau plasma levels in subjective cognitive decline: Results from the DELCODE study

Previous studies have demonstrated increased tau plasma levels in patients with Alzheimer’s disease (AD) and mild cognitive impairment (MCI) due to AD. Much less is known whether increased tau plasma levels can already be detected in the pre-MCI stage of subjective cognitive decline (SCD). In the present study we measured tau plasma levels in 111 SCD patients and 134 age- and gender-matched cognitively healthy controls participating in the DZNE (German Center for Neurodegenerative Diseases) longitudinal study on cognition and dementia (DELCODE). Tau plasma levels were measured using ultra-sensitive, single-molecule array (Simoa) technology. We found no significant different tau plasma levels in SCD (3.4 pg/ml) compared with healthy controls (3.6 pg/ml) after controlling for age, gender, and education (p = 0.137). In addition, tau plasma levels did not correlate with Aβ42 (r = 0.073; p = 0.634), tau (r = −0.179; p = 0.240), and p-tau181 (r = −0.208; p = 0.171) cerebrospinal fluid (CSF) levels in a subgroup of 45 SCD patients with available CSF. In conclusion, plasma tau is not increased in SCD patients. In addition, the lack of correlation between tau in plasma and CSF in the examined cohort suggests that tau levels are affected by different factors in both biofluids.

Cognitive Variability during Middle-Age: Possible Association with Neurodegeneration and Cognitive Reserve

Objective: Increased variability in cognition with age has been argued as an indication of pathological processes. Focusing on early detection of neurodegenerative disorders, we investigated variability in cognition in healthy middle-aged adults. In order to understand possible determinants of this variability, we also investigated associations with cognitive reserve, neuroimaging markers, subjective memory complaints, depressive symptomatology, and gender.

Method: Thirty-one 50 ± 2 years old individuals were investigated as target group and deviation was studied in comparison to a reference younger group of 30 individuals 40 ± 2 years old. Comprehensive neuropsychological and structural imaging protocols were collected. Brain regional volumes and cortical thickness were calculated with FreeSurfer, white matter hyperintensities with CASCADE, and mean diffusivity with FSL.

Results: Across-individuals variability showed greater dispersion in lexical access, processing speed, executive functions, and memory. Variability in global cognition correlated with, reduced cortical thickness in the right parietal-temporal-occipital association cortex, and increased mean diffusivity in the cingulum bundle and right inferior fronto-occipital fasciculus. A trend was also observed for the correlation between global cognition and hippocampal volume and female gender. All these associations were influenced by cognitive reserve. No correlations were found with subjective memory complaints, white matter hyperintensities and depressive symptomatology. Across-domains and across-tasks variability was greater in several executive components and cognitive processing speed.

Conclusion: Variability in cognition during middle-age is associated with neurodegeneration in the parietal–temporal–occipital association cortex and white matter tracts connecting this to the prefrontal dorsolateral cortex and the hippocampus. Moreover, this effect is influenced by cognitive reserve. Studying variability offers valuable information showing that differences do not occur in the same magnitude and direction across individuals, cognitive domains and tasks. These findings may have important implications for early detection of subtle cognitive impairment and clinical interpretation of deviation from normality.

Longitudinal evaluation of criteria for subjective cognitive decline and preclinical Alzheimer's disease in a memory clinic sample

INTRODUCTION

Subjective cognitive decline (SCD) and biomarker-based "at-risk" concepts such as "preclinical" Alzheimer's disease (AD) have been developed to predict AD dementia before objective cognitive impairment is detectable. We longitudinally evaluated cognitive outcome when using these classifications.

METHODS

Memory clinic patients (n = 235) were classified as SCD (n = 122): subtle cognitive decline (n = 36) and mild cognitive impairment (n = 77) and subsequently subclassified into SCDplus and National Institute on Aging-Alzheimer's Association (NIA-AA) stages 0 to 3. Mean (standard deviation) follow-up time was 48 (35) months. Proportion declining cognitively and prognostic accuracy for cognitive decline was calculated for all classifications.

RESULTS

Among SCDplus patients, 43% to 48% declined cognitively. Among NIA-AA stage 1 to 3 patients, 50% to 100% declined cognitively. The highest positive likelihood ratios (+LRs) for subsequent cognitive decline (+LR 6.3), dementia (+LR 3.4), and AD dementia (+LR 6.5) were found for NIA-AA stage 2.

DISCUSSION

In a memory clinic setting, NIA-AA stage 2 seems to be the most successful classification in predicting objective cognitive decline, dementia, and AD dementia.

Dissociable diffusion MRI patterns of white matter microstructure and connectivity in Alzheimer's disease spectrum

Recent efforts using diffusion tensor imaging (DTI) have documented white matter (WM) alterations in Alzheimer's disease (AD). The full potential of whole-brain DTI, however, has not been fully exploited as studies have focused on individual microstructural indices independently. In patients with AD (n = 79), mild (MCI, n = 55) and subjective (SCI, n = 30) cognitive impairment, we applied linked independent component analysis (LICA) to model inter-subject variability across five complementary DTI measures (fractional anisotropy (FA), axial/radial/mean diffusivity, diffusion tensor mode), two crossing fiber measures estimated using a multi-compartment crossing-fiber model reflecting the volume fraction of the dominant (f1) and non-dominant (f2) diffusion orientation, and finally, connectivity density obtained from full-brain probabilistic tractography. The LICA component explaining the largest data variance was highly sensitive to disease severity (AD < MCI < SCI) and revealed widespread coordinated decreases in FA and f1 with increases in all diffusivity measures in AD. Additionally, it reflected regional coordinated decreases and increases in f2, mode and connectivity density, implicating bidirectional alterations of crossing fibers in the fornix, uncinate fasciculi, corpus callosum and major sensorimotor pathways. LICA yielded improved diagnostic classification performance compared to univariate region-of-interest features. Our results document coordinated WM microstructural and connectivity alterations in line with disease severity across the AD continuum.

Implementation of subjective cognitive decline criteria in research studies

INTRODUCTION

Subjective cognitive decline (SCD) manifesting before clinical impairment could serve as a target population for early intervention trials in Alzheimer's disease (AD). A working group, the Subjective Cognitive Decline Initiative (SCD-I), published SCD research criteria in the context of preclinical AD. To successfully apply them, a number of issues regarding assessment and implementation of SCD needed to be addressed.

METHODS

Members of the SCD-I met to identify and agree on topics relevant to SCD criteria operationalization in research settings. Initial ideas and recommendations were discussed with other SCD-I working group members and modified accordingly.

RESULTS

Topics included SCD inclusion and exclusion criteria, together with the informant's role in defining SCD presence and the impact of demographic factors.

DISCUSSION

Recommendations for the operationalization of SCD in differing research settings, with the aim of harmonization of SCD measurement across studies are proposed, to enhance comparability and generalizability across studies.

Generalization of Context-Specific Training in Individuals with Mild Cognitive Impairment: An Event-Related Potential Study

Background

This study examined the neural processes associated with the generalization of the effect of context-specific (CS) training to noncontextual situations among individuals with mild cognitive impairment (MCI).

Methods

Fourteen and 16 participants with MCI were randomly allocated to a Chinese calligraphy writing (CW) training or a control group, respectively. The CW participants learned how to write Chinese strokes in a semicursive style to construct characters, tapping on working memory functions. The control group, on the other hand, learned how to use a tablet computer without emphasis on working memory functions. They then performed two 2-back tasks with CS semicursive strokes and non-context-specific (NCS) digits. Event-related electroencephalogram signals were concurrently recorded.

Results

The CW participants had a significantly shorter reaction time in the CS than in the NCS task (p < 0.05). They showed significantly longer latency in working memory updating (N200; t<Sub>11</Sub> = 4.70, p = 0.05) and shorter latency in the evaluation of visual representation (P300; t<Sub>12</Sub> = 4.67; p = 0.05) than the control group when performing the 2-back CS task. Shorter P300 latency was also revealed in the 2-back NCS task (t<Sub>12</Sub> = 5.15, p = 0.041), suggesting a possible generalization of the training effect among the CW participants.

Conclusion

The results suggest that CS working memory is likely to be generalized to NCS domains among individuals with MCI. Future research should extend the scope of the generalization and apply it beyond experimental conditions.

Non-Invasive Brain Stimulation: A New Strategy in Mild Cognitive Impairment?

Non-invasive brain stimulation (NIBS) techniques can significantly modulate cognitive functions in healthy subjects and patients with neuropsychiatric disorders. Recently, they have been applied in patients with mild cognitive impairment (MCI) and subjective cognitive impairment (SCI) to prevent or delay the development of Alzheimer’s disease (AD). Here we review this emerging empirical corpus and discuss therapeutic effects of NIBS on several target functions (e.g., memory for face-name associations and non-verbal recognition, attention, psychomotor speed, everyday memory). Available studies have yielded mixed results, possibly due to differences among their tasks, designs, and samples, let alone the latter’s small sizes. Thus, the impact of NIBS on cognitive performance in MCI and SCI remains to be determined. To foster progress in this direction, we outline methodological approaches that could improve the efficacy and specificity of NIBS in both conditions. Furthermore, we discuss the need for multicenter studies, accurate diagnosis, and longitudinal approaches combining NIBS with specific training regimes. These tenets could cement biomedical developments supporting new treatments for MCI and preventive therapies for AD.

Impact of Physical Activity on Cognitive Decline, Dementia, and Its Subtypes: Meta-Analysis of Prospective Studies

The association of physical activity with dementia and its subtypes has remained controversial in the literature and has continued to be a subject of debate among researchers. A systematic review and meta-analysis of longitudinal studies on the relationship between physical activity and the risk of cognitive decline, all-cause dementia, Alzheimer's disease, and vascular dementia among nondemented subjects are considered. A comprehensive literature search in all available databases was conducted up until April 2016. Well-defined inclusion and exclusion criteria were developed with focus on prospective studies ≥ 12 months. The overall sample from all studies is 117410 with the highest follow-up of 28 years. The analyses are performed with both Bayesian parametric and nonparametric models. Our analysis reveals a protective effect for high physical activity on all-cause dementia, odds ratio of 0.79, 95% CI (0.69, 0.88), a higher and better protective effect for Alzheimer's disease, odds ratio of 0.62, 95% CI (0.49, 0.75), cognitive decline odds ratio of 0.67, 95% CI (0.55, 0.78), and a nonprotective effect for vascular dementia of 0.92, 95% CI (0.62, 1.30). Our findings suggest that physical activity is more protective against Alzheimer's disease than it is for all-cause dementia, vascular dementia, and cognitive decline.

Disrupted global metastability and static and dynamic brain connectivity across individuals in the Alzheimer's disease continuum

As findings on the neuropathological and behavioral components of Alzheimer's disease (AD) continue to accrue, converging evidence suggests that macroscale brain functional disruptions may mediate their association. Recent developments on theoretical neuroscience indicate that instantaneous patterns of brain connectivity and metastability may be a key mechanism in neural communication underlying cognitive performance. However, the potential significance of these patterns across the AD spectrum remains virtually unexplored. We assessed the clinical sensitivity of static and dynamic functional brain disruptions across the AD spectrum using resting-state fMRI in a sample consisting of AD patients (n = 80) and subjects with either mild (n = 44) or subjective (n = 26) cognitive impairment (MCI, SCI). Spatial maps constituting the nodes in the functional brain network and their associated time-series were estimated using spatial group independent component analysis and dual regression, and whole-brain oscillatory activity was analyzed both globally (metastability) and locally (static and dynamic connectivity). Instantaneous phase metrics showed functional coupling alterations in AD compared to MCI and SCI, both static (putamen, dorsal and default-mode) and dynamic (temporal, frontal-superior and default-mode), along with decreased global metastability. The results suggest that brains of AD patients display altered oscillatory patterns, in agreement with theoretical premises on cognitive dynamics.

2016 Alzheimer's disease facts and figures

This report describes the public health impact of Alzheimer's disease, including incidence and prevalence, mortality rates, costs of care, and the overall impact on caregivers and society. It also examines in detail the financial impact of Alzheimer's on families, including annual costs to families and the difficult decisions families must often make to pay those costs. An estimated 5.4 million Americans have Alzheimer's disease. By mid-century, the number of people living with Alzheimer's disease in the United States is projected to grow to 13.8 million, fueled in large part by the aging baby boom generation. Today, someone in the country develops Alzheimer's disease every 66 seconds. By 2050, one new case of Alzheimer's is expected to develop every 33 seconds, resulting in nearly 1 million new cases per year. In 2013, official death certificates recorded 84,767 deaths from Alzheimer's disease, making it the sixth leading cause of death in the United States and the fifth leading cause of death in Americans age ≥ 65 years. Between 2000 and 2013, deaths resulting from stroke, heart disease, and prostate cancer decreased 23%, 14%, and 11%, respectively, whereas deaths from Alzheimer's disease increased 71%. The actual number of deaths to which Alzheimer's disease contributes is likely much larger than the number of deaths from Alzheimer's disease recorded on death certificates. In 2016, an estimated 700,000 Americans age ≥ 65 years will die with Alzheimer's disease, and many of them will die because of the complications caused by Alzheimer's disease. In 2015, more than 15 million family members and other unpaid caregivers provided an estimated 18.1 billion hours of care to people with Alzheimer's and other dementias, a contribution valued at more than $221 billion. Average per-person Medicare payments for services to beneficiaries age ≥ 65 years with Alzheimer's disease and other dementias are more than two and a half times as great as payments for all beneficiaries without these conditions, and Medicaid payments are 19 times as great. Total payments in 2016 for health care, long-term care and hospice services for people age ≥ 65 years with dementia are estimated to be $236 billion. The costs of Alzheimer's care may place a substantial financial burden on families, who often have to take money out of their retirement savings, cut back on buying food, and reduce their own trips to the doctor. In addition, many family members incorrectly believe that Medicare pays for nursing home care and other types of long-term care. Such findings highlight the need for solutions to prevent dementia-related costs from jeopardizing the health and financial security of the families of people with Alzheimer's and other dementias.

White matter hyperintensity microstructure in amyloid dysmetabolism

Accumulating evidence suggests associations between cerebrovascular disease (CVD) and Alzheimer's disease (AD). White matter hyperintensities of presumed vascular origin (WMHs) are increased in subjects with mild cognitive impairment (MCI) and AD, but the exact pathomechanistic link is unknown. The current study investigated effects of amyloid dysmetabolism on the microstructure of WMHs in subjects with MCI or subjective cognitive decline (N = 51), dichotomized according to pathological or normal levels of amyloid-β peptide (Aβ42) in cerebrospinal fluid (CSF). Thirty-one subjects with low CSF Aβ42 (Aβ+) and 20 subjects with normal CSF Aβ42 (Aβ-) were assessed with magnetic resonance diffusion tensor imaging (DTI), and fractional anisotropy (FA), radial diffusivity (DR), axial diffusivity (DA), and mean diffusivity (MD) were determined. There were no significant differences in WMH volume or distribution between the groups, and neither age nor WMH volume had significant impact on the DTI indices. Nevertheless, there were significantly higher DA, DR, and MD in WMHs in Aβ+ relative to Aβ-; however, no differences in FA were found. The present results suggest that amyloid accumulation is associated with impaired structural integrity (e.g. relating to more extensive demyelination and loss of axons) in WMHs putatively adding to effects of ischemia.

Cognitive complaints in older adults at risk for Alzheimer's disease are associated with altered resting-state networks

INTRODUCTION

Pathophysiological changes that accompany early clinical symptoms in prodromal Alzheimer's disease (AD) may have a disruptive influence on brain networks. We investigated resting-state functional magnetic resonance imaging (rsfMRI), combined with brain connectomics, to assess changes in whole-brain functional connectivity (FC) in relation to neurocognitive variables.

METHODS

Participants included 58 older adults who underwent rsfMRI. Individual FC matrices were computed based on a 278-region parcellation. FastICA decomposition was performed on a matrix combining all subjects' FC. Each FC pattern was then used as a response in a multilinear regression model including neurocognitive variables associated with AD (cognitive complaint index [CCI] scores from self and informant, an episodic memory score, and an executive function score).

RESULTS

Three connectivity independent component analysis (connICA) components (RSN, VIS, and FP-DMN FC patterns) associated with neurocognitive variables were identified based on prespecified criteria. RSN-pattern, characterized by increased FC within all resting-state networks, was negatively associated with self CCI. VIS-pattern, characterized by an increase in visual resting-state network, was negatively associated with CCI self or informant scores. FP-DMN-pattern, characterized by an increased interaction of frontoparietal and default mode networks (DMN), was positively associated with verbal episodic memory.

DISCUSSION

Specific patterns of FC were differently associated with neurocognitive variables thought to change early in the course of AD. An integrative connectomics approach relating cognition to changes in FC may help identify preclinical and early prodromal stages of AD and help elucidate the complex relationship between subjective and objective indices of cognitive decline and differences in brain functional organization.

Amyloid Dysmetabolism Relates to Reduced Glucose Uptake in White Matter Hyperintensities

Alzheimer’s disease (AD) is the most prevalent neurodegenerative disorder and cause of dementia and is characterized by amyloid plaques and neurofibrillary tangles. AD has traditionally been considered to primarily affect gray matter, but multiple lines of evidence also indicate white matter (WM) pathology and associated small-vessel cerebrovascular disease. WM glucose delivery and metabolism may have implications for local tissue integrity, and [¹⁸F]-fluorodeoxyglucose positron emission tomography (FDG-PET) may be helpful to assess neuroglial and axonal function in WM. Hypothesizing that affection of oligodendroglia will be associated with loss of glucose uptake, we aimed to investigate glucose metabolism in magnetic resonance imaging (MRI) white matter hyperintensities (WMHs) and normal-appearing WM in patients with and without evidence of amyloid plaques. Subjects with mild cognitive impairment or subjective cognitive decline were included and dichotomized according to pathological (Aβ+) or normal (Aβ−) concentrations of cerebrospinal fluid amyloid-β 1–42. A total of 50 subjects were included, of whom 30 subjects were classified as Aβ(+) and 20 subjects as Aβ(−). All subjects were assessed with MRI and FDG-PET. FDG-PET images were corrected for effects of partial voluming and normalized to cerebellar WM, before determining WMH FDG-uptake. Although there were no significant differences between the groups in terms of age, WMH volume, number of individual WMHs, or WMH distribution, we found significantly lower (p = 0.021) FDG-uptake in WMHs in Aβ(+) subjects (mean = 0.662, SD = 0.113) compared to Aβ(−) subjects (mean = 0.596, SD = 0.073). There were no significant group differences in the FDG-uptake in normal-appearing WM. Similar results were obtained without correction for effects of partial voluming. Our findings add to the evidence for a link between Aβ dysmetabolism and WM pathology in AD.

Anxiety and depression symptoms among caregivers of care-recipients with subjective cognitive decline and cognitive impairment

Background

Caregivers of care-recipients with mild cognitive impairment (MCI) or dementia experience high caregiver burden; however, the psychiatric burden of caregivers of care-recipients with subjective cognitive decline (SCD) has not been investigated. We aimed to explore the prevalence of and risk factors for anxiety and depression symptoms among the caregivers of care-recipients with SCD and cognitive impairment.

Methods

The Hospital Anxiety and Depression Scale (HADS) was used to examine the anxiety and depression symptoms among the caregivers of 343 care-recipients (84 with SCD, 120 with MCI and 139 with dementia) treated at the Memory Clinic of Huashan Hospital in Shanghai, China from May 2012 to October 2014. A logistic regression was used to explore the factors associated with caregiver’s anxiety and depression symptoms.

Results

In total, 26.5 % of caregivers had anxiety symptoms, and 22.4 % had depression symptoms. Totals of 17.9, 30.0 and 28.8 % of caregivers of care-recipients with SCD, MCI or dementia, respectively, had anxiety symptoms (P = 0.1140), whereas 22.6, 24.2 and 20.9 %, respectively, had depression symptoms (P = 0.8165). The risk factors for caregiver’s anxiety symptoms were increased caregiver age as well as having care-recipients who were male, had higher Cohen Mansfield Agitation Inventory (CMAI) scores, and higher Geriatric Depression Scale (GDS) scores. The risk factors for caregiver’s depression symptoms were increased caregiver age as well as caring for care-recipients with MCI or SCD, those with lower Toronto Empathy Questionnaire (TEQ) scores, and those with higher GDS scores.

Conclusions

Caregivers of care-recipients with SCD showed the same level of depression symptoms as those of care-recipients with MCI. Caregiver’s depression and anxiety symptoms were associated with their care-recipients’ psychiatric and behavioral syndromes.

Differences in quantitative methods for measuring subjective cognitive decline - results from a prospective memory clinic study

BACKGROUND

Cognitive complaints occur frequently in elderly people and may be a risk factor for dementia and cognitive decline. Results from studies on subjective cognitive decline are difficult to compare due to variability in assessment methods, and little is known about how different methods influence reports of cognitive decline.

METHODS

The Subjective Memory Complaints Scale (SMC) and The Memory Complaint Questionnaire (MAC-Q) were applied in 121 mixed memory clinic patients with mild cognitive symptoms (mean MMSE = 26.8, SD 2.7). The scales were applied independently and raters were blinded to results from the other scale. Scales were not used for diagnostic classification. Cognitive performances and depressive symptoms were also rated. We studied the association between the two measures and investigated the scales' relation to depressive symptoms, age, and cognitive status.

RESULTS

SMC and MAC-Q were significantly associated (r = 0.44, N = 121, p = 0.015) and both scales had a wide range of scores. In this mixed cohort of patients, younger age was associated with higher SMC scores. There were no significant correlations between cognitive test performances and scales measuring subjective decline. Depression scores were significantly correlated to both scales measuring subjective decline. Linear regression models showed that age did not have a significant contribution to the variance in subjective memory beyond that of depressive symptoms.

CONCLUSIONS

Measures for subjective cognitive decline are not interchangeable when used in memory clinics and the application of different scales in previous studies is an important factor as to why studies show variability in the association between subjective cognitive decline and background data and/or clinical results. Careful consideration should be taken as to which questions are relevant and have validity when operationalizing subjective cognitive decline.

A Conceptualization of the Utility of Subjective Cognitive Decline in Clinical Trials of Preclinical Alzheimer's Disease

This commentary outlines a conceptual model for subjective cognitive decline (SCD) in relation to Alzheimer's disease (AD) biomarkers in the preclinical stages of disease and a framework for effectively utilizing SCD in secondary prevention clinical trials. Mounting evidence supports the notion that SCD is sensitive to encroaching Aβ-amyloid and neurodegeneration. SCD has also been shown to provide additive information of AD-dementia risk beyond what is known about the biomarker status of the individual. Thus, we provide recommendations for the implementing SCD measurement in clinical trials. We argue that SCD can be measured at three catch points within the course of the clinical trial: firstly, at the initial recruitment and screening phase; secondly, to create more robust estimates of rates of AD-dementia progression; and finally, to measure subjective experiences of cognitive change and quality of life over the course of the trial as a proxy of clinically meaningful functional improvement. We provide recommendations of how SCD can be approached at each of these points. SCD is an important component of the preclinical AD-dementia trajectory. Future studies need to elucidate the interactive influence of Aβ-amyloid and tau on SCD from a spatiotemporal perspective. Even as this evidence accrues, it is clear that SCD can provide unique and additive information about rates of progression and subjectively experienced cognitive change within clinical trials.

Concordance between Subjective and Objective Memory Impairment in Volunteer Subjects

BACKGROUND

Subjective memory impairment (SMI) refers to subjective awareness of initial memory decline undetectable with existing standardized cognitive tests. The Face Name Associative Memory Exam (FNAME) was created to detect memory deficits in individuals with preclinical Alzheimer's disease (AD). We reported normative data of a Spanish version of FNAME (S-FNAME) in cognitively normal (CN) Spanish-speaking subjects >49.

OBJECTIVE

To determine whether higher SMI [a modification of Memory Failures Everyday (MFE-30)] was related to worse memory performance (S-FNAME) or associated with greater affective symptoms in subjects >49; and whether MFE-30 and FNAME were able to discriminate between CN and mild cognitive impairment (MCI) subjects.

METHODS

317 subjects (CN = 196, MCI = 121) were included in the analysis because they attended the annual "Open House Initiative" at Memory Clinic Fundació ACE, were >49 years, literate, received S-FNAME, MFE-30, and Hospital Anxiety and Depression Scale, had Mini-Mental State Examination scores ≥27, and returned to complete a comprehensive diagnostic assessment.

RESULTS

MFE-30 scores were associated with affective symptoms but not with S-FNAME performance. S-FNAME scores were related to performance on memory variables of NBACE (neuropsychological battery used in Fundació ACE). Although the MCI group showed significantly higher MFE-30 and worse S-FNAME scores than the CN group, their discriminability values were similar (Sensitivity: 49.6 versus 52.9; Specificity: 85.1 versus 83.6, respectively).

CONCLUSIONS

SMI was more related to depressive symptoms than to S-FNAME memory performance; and S-FNAME scores were related to other episodic memory test performances, but neither to affective symptoms nor to SMI. MFE-30 and S-FNAME are not optimal for discriminating between CN and MCI groups. Longitudinal follow-up will determine if lower S-FNAME and higher SMI are related to increased risk of AD.

Non-invasive brain stimulation of the aging brain: State of the art and future perspectives

Favored by increased life expectancy and reduced birth rate, worldwide demography is rapidly shifting to older ages. The golden age of aging is not only an achievement but also a big challenge because of the load of the elderly on social and medical health care systems. Moreover, the impact of age-related decline of attention, memory, reasoning and executive functions on self-sufficiency emphasizes the need of interventions to maintain cognitive abilities at a useful degree in old age. Recently, neuroscientific research explored the chance to apply Non-Invasive Brain Stimulation (NiBS) techniques (as transcranial electrical and magnetic stimulation) to healthy aging population to preserve or enhance physiologically-declining cognitive functions. The present review will update and address the current state of the art on NiBS in healthy aging. Feasibility of NiBS techniques will be discussed in light of recent neuroimaging (either structural or functional) and neurophysiological models proposed to explain neural substrates of the physiologically aging brain. Further, the chance to design multidisciplinary interventions to maximize the efficacy of NiBS techniques will be introduced as a necessary future direction.

Subjective Cognitive Decline from a Phenomenological Perspective: A Review of the Qualitative Literature

BACKGROUND

Subjective cognitive decline is related to greater risk of dementia and biological markers of Alzheimer's disease (AD), but researchers are yet to characterize the phenomenological perspective of cognitive decline in those with and without a diagnosis of AD.

OBJECTIVE

To collate and synthesize studies measuring the subjective experience of cognitive change or decline in healthy older adults and those with mild cognitive impairment and AD.

METHODS

We reviewed 58 peer-reviewed articles that were found to directly or indirectly refer to the subjective experience of cognitive decline.

RESULTS

We extracted eight central themes, dealing with cognitive changes experienced by each diagnostic group, and also related to issues of changing self-identity, the causal attribution of cognitive decline, the anxiety and concern related to perceived decline, the negative perceptions attached to a diagnosis of dementia, changing levels of insight, and perception of well-being in aging.

CONCLUSION

This review is the first step toward characterizing phenomenological profiles of cognitive change in both non-demented and demented older adults. Developing a clearer understanding of subjective cognitive decline, particularly at the earliest stages of AD, will augment the sensitivity of detection of individuals at greater risk of future dementia.

Everyday functioning and cognitive correlates in healthy older adults with subjective cognitive concerns

OBJECTIVE

Few studies have examined functional abilities and complaints in healthy older adults (HOAs) with subjective cognitive concerns (SCC). The aims of this study were to assess everyday functioning in HOAs reporting high and low amounts of SCC and examine cognitive correlates of functional abilities.

METHOD

Twenty-six HOAs with high SCC and 25 HOAs with low SCC, as well as their knowledgeable informants, completed the Instrumental Activities of Daily Living-Compensation (IADL-C), a questionnaire measure of everyday functioning.

RESULTS

After controlling for depression, the high-SCC group self-reported significantly more everyday difficulties on the IADL-C, including all subdomains. Compared to the low-SCC group, informants for the high-SCC group endorsed more difficulties on the IADL-C and specifically the social skills subdomain. For the high-SCC group, poorer self-report of everyday functioning was related to poorer executive functioning and temporal order memory.

CONCLUSIONS

These findings indicate that there may be subtle functional changes that occur early in the spectrum of cognitive decline in individuals with high SCC, and these functional changes are evident to informants. Further work is needed to investigate whether individuals with both SCC and functional difficulties are at an even higher risk for progression to mild cognitive impairment.