Are subjective cognitive complaints relevant in preclinical Alzheimer's disease? A review and guidelines for healthcare professionals

Are subjective language complaints in memory clinic patients informative?

To diagnose mild cognitive impairment, it is crucial to understand whether subjective cognitive complaints reflect objective cognitive deficits. This question has mostly been investigated in the memory domain, with mixed results. Our study was one of the first to address it for language. Participants were 55-to-93-year-old memory clinic patients (n = 163). They filled in a questionnaire about subjective language and memory complaints and performed two language tasks (naming-by-definition and sentence comprehension). Greater language complaints were associated with two language measures, thus showing a moderate value in predicting language performance. Greater relative severity of language versus memory complaints was a better predictor, associated with three language performance measures. Surprisingly, greater memory complaints were associated with better naming, probably due to anosognosia in further disease progression or personality-related factors. Our findings highlight the importance of relative complaint severity across domains and, clinically, call for developing self-assessment questionnaires asking specific questions about multiple cognitive functions.

Predicting amyloid positivity from FDG-PET images using radiomics: A parsimonious model

BACKGROUND AND OBJECTIVE

Amyloid plaques are one of the physical hallmarks of Alzheimer's disease. The objective of this study is to predict amyloid positivity non-invasively from FDG-PET images using a radiomics approach.

METHODS

We obtained FDG-PET images of 301 individuals from various groups, including control normal (CN), mild cognitive impairment (MCI), and Alzheimer's Disease (AD), from the ADNI database. Following the utilization of the CSF Aβ1-42 (192) and Standardized Uptake Value Ratio (SUVR) (1.11) thresholds derived from Florbetapir scans, the subjects were categorized into two categories: those with a positive amyloid status (n = 185) and those with a negative amyloid status (n = 116). The process of segmenting the entire brain into 95 classes using the DKT-atlas was utilized. Following that, we obtained 120 characteristics for each of the 95 regions of interest (ROIs). We employed eight feature selection methods to analyze the features. Additionally, we utilized eight different classifiers on the 20 most significant features extracted from each feature selection method. Finally, in order to improve interpretability, we selected the most important features and ROIs.

RESULT

We found that the GNB classifier and the LASSO feature selection method had the best performance with an average accuracy of (AUC=0.924) while using 18 features on 15 ROIs. We were then able to reduce the model to three regions (Hippocampus, inferior parietal, and isthmus cingulate) and three gray-level based features (AUC=0.853).

CONCLUSION

The FDG-PET images which serve to study metabolic activity can be used to predict amyloid positivity without the use of invasive methods or another PET tracer and study. The proposed method has superior prediction accuracy with respect to similar studies reported in the literature using other imaging modalities. Only three brain regions had a high impact on amyloid positivity results.

Association of cognitive function very early after stroke with subjective cognitive complaints after 3 months, a register-based study

OBJECTIVE

Cognitive deficits are commonly observed after stroke and have been associated with the cognitive decline and development of dementia in later stages. This study aimed to investigate whether cognition screened at acute stroke units could explain subjective cognitive complaints 3 months after stroke and evaluate how the severity of stroke and age could influence this association.

METHODS

In this register-based longitudinal study, data were retrieved from three Swedish registers between November 2014 and June 2019. Information on subjective cognitive complaints (SCC) was collected from the Riksstroke 3-month follow-up form, which were used to analyze the primary outcomes. Cognitive function screened using the Montreal Cognitive Assessment (MoCA) at acute stroke units was expressed as the primary independent variable.

RESULTS

Of the 1977 patients included in the study, 58% were males, the median age was 73 years, and 63% had a minor stroke. A total of 60% of patients had impaired cognition at acute stroke units (MoCA score, <26), of whom 40.3% reported at least 1 cognitive problem after 3 months. In adjusted binary regression analysis models, patients with normal cognitive function had lower odds for SCCs. This pattern was observed regardless of age and in patients with a minor stroke.

CONCLUSIONS

Intact cognition early after stroke was related to decreased odds of subjective cognitive complaints at the 3-month follow-up. This study highlights the importance of both early cognitive screening after stroke and subjective cognitive complaints, which have been shown to be associated with cognitive decline. Furthermore, we suggest the importance of discussing cognitive function with patients during regular follow-up in primary care, usually 3 months after stroke.

Can subjective cognitive complaints at three months post stroke predict alteration in information processing speed during the first year?

Cognitive impairment, particularly slowing of information processing speed (IPS), is prevalent after stroke. However, the link between subjective cognitive complaints (SCC) and cognitive deficit remains unclear. This study evaluated the link between SCC at three months post stroke and deficit as well as objective alterations in IPS in the first year post stroke. Patients (N = 200) and healthy controls (N = 105) took part in the COMPlaints After Stroke study (COMPAS). SCC, IPS and depression were evaluated at 3 months, 1 and 2 years post stroke. The Reliable Change Index was used to assess change in IPS in the first year post. Approximately one out of three patients showed deficit in IPS irrespective of time post stroke, while a change in IPS (N = 117) over time was relatively uncommon. SCC at three months post stroke did not predict change in IPS between three months and one year post stroke, where depressive symptoms did show a link. Cross sectional data showed a deficit in IPS in a substantial number of stroke patients irrespective of the point in time. Longitudinal data revealed a further decline in a small subgroup in the first year post stroke, which was not predicted by SCC at three months post stroke. The findings show that, irrespective of time post stroke and even when stroke is relatively mild, impairment in IPS is prevalent, but cannot be predicted by the complaints patients express. The link with depressive symptoms needs more exploration.

Compensatory and Lifestyle-Based Brain Health Program for Subjective Cognitive Decline: Self-Implementation versus Coaching

Although recent studies have explored the potential of multidomain brain health programs, there is a dearth of literature on operationalizing this research to create a clinical treatment program specifically for subjective cognitive decline (SCD). Patients seen by geriatricians in primary care and by behavioral neurology services at our institution presenting with SCD were recruited via a patient-appropriate flyer. After all participants had a 1-h brain health consultation with a neuropsychologist and were provided with program materials, they were randomized to attend a 10-week intervention designed to support program implementation (N = 10) or the control group of implementing the program on their own (N = 11). The program included (1) a calendar-based executive and memory support system for compensatory training and (2) training in healthy lifestyle. There were no significant differences between groups for any outcomes. Participants across both groups showed significant improvements with moderate effect sizes in compensatory strategy use, anxiety symptoms, and daily functioning, which were sustained through 6-month follow-up. They also increased physical activity by the end of the intervention period but did not sustain this through 6-month follow-up. Our pilot study demonstrates preliminary feasibility of a cognitive compensatory and lifestyle-based brain health program. Additional research is recommended to further develop two potentially scalable implementation strategies—coaching and self-implementation after brief consultation.

The roles of study setting, response bias, and personality in subjective memory complaints of cognitively normal older adults

OBJECTIVES

This study investigated subjective memory complaints in older adults and the roles of setting, response bias, and personality.

DESIGN

Cognitively normal older adults from two settings completed questionnaires measuring memory complaints, response bias, and personality.

SETTINGS

(A) Neuroimaging study with community-based recruitment and (B) academic memory clinic.

PARTICIPANTS

Cognitively normal older adults who (A) volunteer for research (N = 92) or (B) self-referred to a memory clinic (N = 20).

MEASUREMENTS

Neuropsychological evaluation and adjudication of normal cognitive status were done by the neuroimaging study or memory clinic. This study administered self-reports of subjective memory complaints, response bias, five-factor personality, and depressive symptoms. Primary group differences were examined with secondary sensitivity analyses to control for sex, age, and education differences.

RESULTS

There was no significant difference in over-reporting response bias between study settings. Under-reporting response bias was higher in volunteers. Cognitive complaints were associated with response bias for two cognitive complaint measures. Neuroticism was positively associated with over-reporting in evaluation-seekers and negatively associated with under-reporting in volunteers. The relationship was reversed for Extraversion. Under-reporting bias was positively correlated with Agreeableness and Conscientiousness in volunteers.

CONCLUSION

Evaluation-seekers do not show bias toward over-reporting symptoms compared to volunteers. Under-reporting response bias may be important to consider when screening for memory impairment in non-help-seeking settings. The Memory Functioning Questionnaire was less sensitive to reporting biases. Over-reporting may be a facet of higher Neuroticism. Findings help elucidate psychological influences on self-perceived cognitive decline and help seeking in aging and may inform different strategies for assessment by setting.

Accelerated long-term forgetting in individuals with subjective cognitive decline and amyloid-β positivity

OBJECTIVES

We studied a sample of cognitively unimpaired individuals, with and without subjective cognitive decline (SCD), in order to investigate accelerated long-term forgetting (ALF) and to explore the relationships between objective and subjective cognitive performance and cerebrospinal fluid (CSF) Alzheimer's disease (AD) biomarkers.

METHODS

Fifty-two individuals were included and SCD was quantified through the Subjective Cognitive Decline Questionnaire (SCD-Q), using its validated cutoff to classify participants as Low SCD-Q (n = 21) or High SCD-Q (n = 31). These groups were further subdivided according to the presence or absence of abnormal levels of CSF Aβ₄₂ . Objective cognitive performance was assessed with the Ancient Farming Equipment Test (AFE-T), a new highly-demanding test that calls for acquisition and retention of novel object/name pairs and allows measuring ALF over a 6-month period.

RESULTS

The High SCD-Q group showed a significantly higher free forgetting rate at 3 months compared to the Low SCD-Q (F [1,44] = 4.72; p < 0.05). When stratifying by amyloid status, High SCD-Q/Aβ+ showed a significantly lower performance than High SCD-Q/Aβ-on the final free and cued learning scores (F [1,27] = 6.44, p < 0.05 and F [1,27] = 7.51, p < 0.05, respectively), the 1-week free and cued recall (F [1,24] = 4.49; p < 0.05 and F [1,24] = 7.10; p < 0.01, respectively), the 1-week cued forgetting rate (F [1,24] = 5.13; p < 0.05), and the 3-month cued recall (F [1,24] = 4.27; p < 0.05). Linear regression analyses showed that higher SCD-Q scores were associated with higher forgetting rates on the AFE-T (β = -0.212; p < 0.05).

CONCLUSIONS

It is possible to detect ALF in individuals with high SCD ratings, appearing especially in those with abnormal CSF Aβ₄₂ levels. Both in research and the clinical field, there is an increasing need of using more demanding cognitive measures, such as the AFE-T, for identifying and tracking the earliest cognitive changes in these populations.

The Cognitive Difficulties Scale (CDS): Psychometric Characteristics in a Clinical Referral Sample

OBJECTIVE

To evaluate the psychometric characteristics of the Cognitive Difficulties Scale (CDS), a 39-item Likert-type self-report instrument that requires a fifth grade reading level. The CDS is a popular instrument that has been shown to predict cognitive decline in older persons.

METHOD

Participants were 512 consecutive outpatient referrals (71% women, mean age 60.6, and education 14.6 years) for a neuropsychological examination in a memory disorders clinic as part of a broader neurodiagnostic workup for cognitive decline. A principal components analysis was followed by a varimax rotation (Kaiser). Factor scores were investigated in relation to multiple internal and external criteria including demographics, Cronbach's alpha, Digit Span, and Wechsler Memory Scale-IV Logical Memory (LM) and Visual Reproduction (VR), and Minnesota Multiphasic Personality Inventory (MMPI)-2 measures of depression, anxiety, somatic preoccupations, and thought disturbance.

RESULTS

Six dimensions of cognitive complaint emerged accounting for 64% of the variance: attention/concentration, praxis, prospective memory, speech problems, memory for people's names, and temporal orientation. The factors showed good internal consistency (alphas > .850). Correlations with Digit Span, LM, and VR were all nonsignificant. CDS scores were associated with MMPI-2 measures of anxiety, depression, somatic preoccupation, and thought disturbance. Percentiles and T-scores were derived for raw scores on the CDS and its six component subscales.

CONCLUSION

The CDS is a multidimensional measure of subjective cognitive complaints that provides clinicians with a psychometrically sound basis for deriving a profile with six subscale scores. The test has clinical utility and is a potentially useful tool in research involving age-related cognitive changes and meta-cognition.

Subjective cognitive decline, anxiety symptoms, and the risk of mild cognitive impairment and dementia

BACKGROUND

Subjective cognitive decline (SCD) and anxiety symptoms both predict neurocognitive disorders, but the two correlate strongly with each other. It is unclear whether they reflect two independent disease processes in the development of neurocognitive disorders and hence deserve separate attention. This cohort study examined whether SCD and anxiety symptoms demonstrate independent risks of mild cognitive disorder and dementia (MCI/dementia).

METHODS

The study included 14,066 participants aged ≥ 50 years and diagnosed with normal cognition at baseline, recruited from Alzheimer's Disease Centers across the USA. The participants were evaluated for SCD and anxiety symptoms at baseline and followed up almost annually for incident MCI/dementia (median follow-up 4.5 years; interquartile range 2.2-7.7 years). SCD and anxiety symptoms were included in Cox regression to investigate their independent risks of MCI/dementia.

RESULTS

SCD and anxiety symptoms demonstrated independent risks of MCI/dementia, with HR 1.9 (95% CI 1.7-2.1) and 1.3 (95% CI 1.2-1.5), respectively. Co-occurring SCD and anxiety symptoms demonstrated the highest risk (HR 2.4, 95% CI 1.9-2.9)-participants in this group had a 25% probability of developing MCI/dementia by 3.1 years (95% 2.4-3.7), compared to 8.2 years among those without SCD or anxiety (95% CI 7.9-8.6). The results remained robust even in the sensitivity analyses that took into account symptom severity and consistency of symptoms in the first 2 annual visits.

CONCLUSIONS

The findings suggest that clinicians should not dismiss one over the other when patients present with both SCD and anxiety and that both constructs may potentially be useful to identify high-risk populations for preventive interventions and trials. The findings also point to the need for further research to clarify on the neurobiological distinctions between SCD and anxiety symptoms, which may potentially enrich our understanding on the pathogenesis of neurocognitive disorders.

Personality Factors and Subjective Cognitive Decline: The FACEHBI Cohort

Individuals with subjective cognitive decline (SCD) have the perception of memory problems without showing impairment on standardized cognitive tests. SCD has been associated with an increased risk of developing Alzheimer's disease (AD). Neuroticism and openness personality dimensions have also been associated with SCD and AD. From the aforementioned, we aimed to ascertain whether the dimensions and traits defined by the Zuckerman-Kuhlman Personality Questionnaire (ZKPQ) differentiate between individuals with SCD and the general population (GP). A total of 187 participants with SCD and mild affective symptomatology recruited from the Fundació ACE Health Brain Initiative (FACEHBI) project completed the ZKPQ. Each SCD participant was matched by sex and age to an individual from the GP. Both samples included 71 men and 116 women with a mean age of 65.9 years. Results indicated that the SCD group scored significantly lower in Neuroticism-Anxiety and Activity than the GP group. Only Activity remained statistically significant in a multivariate analysis. These findings suggest that individuals with SCD have a low energy level and a dislike for an active and busy life. From the obtained results and knowing additional physical activities may delay the conversion from normal aging to cognitive impairment, we encourage promoting this lifestyle in daily routine. The assessment of personality may result in an SCD plus feature, which may serve as an upgrading strategy for future research.

Relationships Between Subjective Cognitive Impairment and Personality Traits: A Systematic Review

This systematic review examined the relationships between personality traits and subjective cognitive impairment (SCI) in older adults without dementia. A comprehensive literature search conducted according to PRISMA guidelines identified empirical investigations of SCI and at least one of the big five personality traits among adults age 60 or older. All articles were critically appraised using the weight of evidence framework and findings were compared, contrasted, and synthesized across studies. Sixteen of the 797 studies initially identified met eligibility criteria. A higher level of SCI was associated with higher neuroticism in 88% of the studies reviewed. In addition, a consistent negative association was identified between conscientiousness and SCI (57% of studies). No consistent relationships between openness, extraversion, or agreeableness and SCI were identified. Overall, this review supports the oft-cited association between higher neuroticism and greater self-reports of cognitive problems; however, the complexity of the relationship between SCI and personality is not yet fully understood. Future research should examine the extent to which different personality traits predispose individuals to report symptoms versus those traits that are associated with increased sensitivity to early indicators of pathological change. [Journal of Gerontological Nursing, 45(2), 27-34.].

Depression, subjective cognitive decline, and the risk of neurocognitive disorders

BACKGROUND

Depression and subjective cognitive decline (SCD) both predict neurocognitive disorders (NCD). However, the two correlate strongly with each other. It remains uncertain whether they reflect independent neurobiological underpinnings which deserve separate attention. This study evaluated the independent risks of NCD associated with depression and SCD.

METHODS

This cohort study included 13,462 participants who were ≥ 50 years and had normal cognition at baseline. The participants were evaluated for depression and SCD and followed up almost annually for incident mild cognitive impairment or dementia (MCI/dementia) (median follow-up = 4.4 years). Depression and SCD were included in Cox-regression to investigate their independent risks of MCI/dementia.

RESULTS

At baseline, 1307 participants (9.7%) had depression and 3582 (26.6%) had SCD. During follow-up, 1490 (11.1%) developed MCI/dementia. Depression and SCD demonstrated independent risks of MCI/dementia (HR 1.4 and 2.0 respectively). The risk was highest when depression and SCD co-occur (HR 2.8), with half of the participants in this group developing MCI/dementia within 7.2 years of follow-up (compared to 12.2 years in participants without depression or SCD).

CONCLUSIONS

The findings may change the clinical approach in managing SCD in depression, suggesting the need for greater emphasis on detecting prodromal NCD. They may also have implications to our understanding of NCD, suggesting the need for further research to delineate the commonalities and distinctions in the neurobiological pathways of depression and SCD.

Executive and Language Subjective Cognitive Decline Complaints Discriminate Preclinical Alzheimer's Disease from Normal Aging

BACKGROUND

There is a need to specify the profile of subjective cognitive decline in preclinical Alzheimer's disease (preAD).

OBJECTIVES

To explore specific items of the Subjective Cognitive Decline Questionnaire (SCD-Q) that discriminate preAD from normal aging.

METHODS

68 cognitively normal older adults were classified as controls (n = 52) or preAD (n = 16) according to amyloid-β (Aβ) levels. An exploratory factor analysis and item analysis of the SCD-Q were performed. Informant reports of the SCD-Q were used to corroborate the findings of self-reports. One-year neuropsychological follow-up was available.

RESULTS

Four SCD-Q factors were extracted: EM-factor (episodic memory), A-factor (attention), O-factor (organization), and L-factor (language). PreAD reported a significantly higher decline in L-factor (F(1) = 6.49; p = 0.014) and A-factor (F(1) = 4.04; p = 0.049) compared to controls, and showed a higher frequency of perceived decline in SCD-Q items related with language and executive tasks (Sig-items.) Significant discriminative powers for Aβ-positivity were found for L-factor (AUC = 0.75; p = 0.003) and A-factor (AUC = 0.74; p = 0.004). Informants in the preAD group confirmed significantly higher scores in L-factor and Sig-items. A significant time×group interaction was found in the Semantic Fluency and Stroop tests, with the preAD group showing a decrease in performance at one-year.

CONCLUSIONS

Our results suggest that SCD-Q items related with language and executive decline may help in prediction algorithms to detect preAD. Validation in an independent population is needed.

Perception and Reality of Cognitive Function: Information Processing Speed, Perceived Memory Function, and Perceived Task Difficulty in Older Adults

This study examines the relationships between two measures of information processing speed associated with executive function (Trail Making Test and a computer-based visual search test), the perceived difficulty of the tasks, and perceived memory function (measured by the Memory Functioning Questionnaire) in older adults (aged 50+ y) with normal general health, cognition (Montreal Cognitive Assessment score of 26+), and mood. The participants were recruited from the community rather than through clinical services, and none had ever sought or received help from a health professional for a memory complaint or mental health problem. For both the trail making and the visual search tests, mean information processing speed was not correlated significantly with perceived memory function. Some individuals did, however, reveal substantially slower information processing speeds (outliers) that may have clinical significance and indicate those who may benefit most from further assessment and follow up. For the trail making, but not the visual search task, higher levels of subjective memory dysfunction were associated with a greater perception of task difficulty. The relationship between actual information processing speed and perceived task difficulty also varied with respect to the task used. These findings highlight the importance of taking into account the type of task and metacognition factors when examining the integrity of information processing speed in older adults, particularly as this measure is now specifically cited as a key cognitive subdomain within the diagnostic framework for neurocognitive disorders.

Risk of progression from subjective cognitive decline to mild cognitive impairment: The role of study setting

INTRODUCTION

We compared risk of progression from subjective cognitive decline (SCD) to mild cognitive impairment (MCI) in an academic memory clinic versus a population-based study.

METHODS

Older adults presenting at a memory clinic were classified as SCD (n = 113) or as noncomplainers (n = 82). Participants from a population study were classified as SCD (n = 592) and noncomplainers (n = 589) based on a memory complaint score. Annual follow-up performed for a mean of 3 years.

RESULTS

The adjusted hazard ratio for SCD was 15.97 (95% confidence interval: 6.08-42.02, P < .001) in the memory clinic versus 1.18 (95% confidence interval: 1.00-1.40, P = .047) in the population study, where reported "worry" about memory further increased SCD-associated risk for MCI.

DISCUSSION

SCD is more likely to progress to MCI in a memory clinic than the general population; participants' characteristics vary across settings. Study setting should be considered when evaluating SCD as a risk state for MCI and dementia.

The role of objective cognitive dysfunction in subjective cognitive complaints after stroke

BACKGROUND AND PURPOSE

Objective cognitive performance (OCP) is often impaired in patients post-stroke but the consequences of OCP for patient-reported subjective cognitive complaints (SCC) are poorly understood. We performed a detailed analysis on the association between post-stroke OCP and SCC.

METHODS

Assessments of OCP and SCC were obtained in 208 patients 3 months after stroke. OCP was evaluated using conventional and ecologically valid neuropsychological tests. Levels of SCC were measured using the CheckList for Cognitive and Emotional (CLCE) consequences following stroke inventory. Multivariate hierarchical regression analyses were used to evaluate the association of OCP with CLCE scores adjusting for age, sex and intelligence quotient. Analyses were performed to examine the global extent of OCP dysfunction (based on the total number of impaired neuropsychological tests, i.e. objective cognitive impairment index) and for each OCP test separately using the raw neuropsychological (sub)test scores.

RESULTS

The objective cognitive impairment index for global OCP was positively correlated with the CLCE score (Spearman's rho = 0.22, P = 0.003), which remained significant in multivariate adjusted models (β = 0.25, P = 0.01). Results for the separate neuropsychological tests indicated that only one task (the ecologically valid Rivermead Behavioural Memory Test) was independently associated with the CLCE in multivariate adjusted models (β = -0.34, P < 0.001).

CONCLUSIONS

Objective neuropsychological test performance, as measured by the global dysfunction index or an ecologically valid memory task, was associated with SCC. These data suggest that cumulative deficits in multiple cognitive domains contribute to subjectively experienced poor cognitive abilities in daily life in patients post-stroke.

Informants' Perception of Subjective Cognitive Decline Helps to Discriminate Preclinical Alzheimer's Disease from Normal Aging

BACKGROUND

Self-reported and informant-reported subjective cognitive decline (SCD) may be useful in the detection of preclinical Alzheimer's disease (Pre-AD) and cognitive impairment related to abnormal amyloid-β (Aβ 42) levels.

OBJECTIVES

a) To compare the Subjective Cognitive Decline Questionnaire (SCD-Q) ratings between Pre-AD subjects and cognitively healthy controls, b) to study the association of SCD-Q scores with levels of AD biomarkers in cognitively healthy and cognitively impaired subjects, and c) to compare SCD-Q ratings in cognitively impaired subjects with or without abnormal Aβ 42.

METHODS

Two hundred and seventeen participants (111 subjects; 106 informants) answered the SCD-Q. All subjects underwent a lumbar puncture to determine levels of Aβ 42 and tau, and an extensive neuropsychological battery. Healthy subjects were classified as Controls (CTR) or Pre-AD according to the absence or the presence of abnormal Aβ 42, and those with cognitive impairment (CI) into Non-amyloid (NonAB-CI) or Amyloid (AB-CI) impairment.

RESULTS

Informants' SCD-Q scores were significantly higher in the Pre-AD group than in the CTR group (F = 6.75; p = 0.01). No significant differences were found in self-ratings. In the cognitively impaired groups, there were no significant differences in the SCD-Q ratings. In the whole sample, informants' ratings of SCD-Q correlated with Aβ 42 (r = -0.21; p = 0.02) and tau levels (r = 0.28; p = 0.00).

CONCLUSIONS

Higher informants' ratings of SCD-Q differentiated Pre-AD subjects from CTR. Informants' ratings of SCD-Q correlated weakly with cerebrospinal fluid AD biomarkers.

Hypertensive Disorders of Pregnancy Appear Not to Be Associated with Alzheimer's Disease Later in Life

Background

After hypertensive disorders of pregnancy, more subjective cognitive complaints and white matter lesions are reported compared to women after normal pregnancies. Both have a causal relationship with Alzheimer's disease (AD).

Aim

To investigate if women whose pregnancy was complicated by hypertensive disorders have an increased risk of AD.

Methods

A case-control study in women with AD from the Alzheimer Center of the VU University Medical Center Amsterdam and women without AD. Paper and telephone surveys were performed.

Results

The response rate was 85.2%. No relation between women with (n = 104) and without AD (n = 129) reporting pregnancies complicated by hypertensive disorders (p = 0.11) was found. Women with early-onset AD reported hypertensive disorders of pregnancy more often (p = 0.02) compared to women with late-onset AD.

Conclusion

A reported history of hypertensive disorders of pregnancy appears not to be associated with AD later in life.

Amyloid-β Imaging in Older Adults Presenting to a Memory Clinic with Subjective Cognitive Decline: A Pilot Study

BACKGROUND

Subjective cognitive decline (SCD) in otherwise normal aging may be identified via symptom inventories in a research setting ('questionnaire-discovered complaints') or via patients seeking evaluation/services in a clinical setting ('presenting complainers'). Most studies of SCD and amyloid-β (Aβ) imaging to date have used the former approach, with inconsistent results.

OBJECTIVE

To test whether 'presenting SCD' participants in an academic memory clinic setting show increased brain Aβ deposition on imaging.

METHODS

Fourteen patients (mean age 68.1, SD 4.0 years) diagnosed with subjective cognitive complaints with normal neuropsychological testing were recruited into a Pittsburgh compound B (PiB)-PET study. Detailed self-report inventories and additional cognitive tests were administered. Results were compared to a reference cohort of cognitively normal volunteers (NC) from an independent neuroimaging study (mean age 73.6, SD 5.8 years).

RESULTS

57% (8/14) of SCD participants were PiB-positive by a sensitive, regionally-based definition, compared to 31% (26/84) of the NC cohort. SCD participants had significantly higher PiB retention (SUVR) than NC in three of six regions of interest: frontal cortex (p = 0.02), lateral temporal cortex (p = 0.02), and parietal cortex (p = 0.04). SCD participants showed measurable deviations on questionnaires reflecting high negative affect (i.e., depressive symptoms and neuroticism). Findings were suggestive that deficits on verbal associative binding may be specific to Aβ-positive versus Aβ-negative SCD.

CONCLUSION

Older participants with SCD presenting to a memory clinic in this pilot study sample have higher brain Aβ deposition compared to normal aging study volunteers unselected on complaints. Further study of presenting SCD are warranted to determine the prognostic significance of Aβ deposition in this context.

Deep sparse multi-task learning for feature selection in Alzheimer's disease diagnosis

Recently, neuroimaging-based Alzheimer's disease (AD) or mild cognitive impairment (MCI) diagnosis has attracted researchers in the field, due to the increasing prevalence of the diseases. Unfortunately, the unfavorable high-dimensional nature of neuroimaging data, but a limited small number of samples available, makes it challenging to build a robust computer-aided diagnosis system. Machine learning techniques have been considered as a useful tool in this respect and, among various methods, sparse regression has shown its validity in the literature. However, to our best knowledge, the existing sparse regression methods mostly try to select features based on the optimal regression coefficients in one step. We argue that since the training feature vectors are composed of both informative and uninformative or less informative features, the resulting optimal regression coefficients are inevidently affected by the uninformative or less informative features. To this end, we first propose a novel deep architecture to recursively discard uninformative features by performing sparse multi-task learning in a hierarchical fashion. We further hypothesize that the optimal regression coefficients reflect the relative importance of features in representing the target response variables. In this regard, we use the optimal regression coefficients learned in one hierarchy as feature weighting factors in the following hierarchy, and formulate a weighted sparse multi-task learning method. Lastly, we also take into account the distributional characteristics of samples per class and use clustering-induced subclass label vectors as target response values in our sparse regression model. In our experiments on the ADNI cohort, we performed both binary and multi-class classification tasks in AD/MCI diagnosis and showed the superiority of the proposed method by comparing with the state-of-the-art methods.

Hierarchical feature representation and multimodal fusion with deep learning for AD/MCI diagnosis

For the last decade, it has been shown that neuroimaging can be a potential tool for the diagnosis of Alzheimer's Disease (AD) and its prodromal stage, Mild Cognitive Impairment (MCI), and also fusion of different modalities can further provide the complementary information to enhance diagnostic accuracy. Here, we focus on the problems of both feature representation and fusion of multimodal information from Magnetic Resonance Imaging (MRI) and Positron Emission Tomography (PET). To our best knowledge, the previous methods in the literature mostly used hand-crafted features such as cortical thickness, gray matter densities from MRI, or voxel intensities from PET, and then combined these multimodal features by simply concatenating into a long vector or transforming into a higher-dimensional kernel space. In this paper, we propose a novel method for a high-level latent and shared feature representation from neuroimaging modalities via deep learning. Specifically, we use Deep Boltzmann Machine (DBM)(2), a deep network with a restricted Boltzmann machine as a building block, to find a latent hierarchical feature representation from a 3D patch, and then devise a systematic method for a joint feature representation from the paired patches of MRI and PET with a multimodal DBM. To validate the effectiveness of the proposed method, we performed experiments on ADNI dataset and compared with the state-of-the-art methods. In three binary classification problems of AD vs. healthy Normal Control (NC), MCI vs. NC, and MCI converter vs. MCI non-converter, we obtained the maximal accuracies of 95.35%, 85.67%, and 74.58%, respectively, outperforming the competing methods. By visual inspection of the trained model, we observed that the proposed method could hierarchically discover the complex latent patterns inherent in both MRI and PET.

Latent feature representation with stacked auto-encoder for AD/MCI diagnosis

Recently, there have been great interests for computer-aided diagnosis of Alzheimer's disease (AD) and its prodromal stage, mild cognitive impairment (MCI). Unlike the previous methods that considered simple low-level features such as gray matter tissue volumes from MRI, and mean signal intensities from PET, in this paper, we propose a deep learning-based latent feature representation with a stacked auto-encoder (SAE). We believe that there exist latent non-linear complicated patterns inherent in the low-level features such as relations among features. Combining the latent information with the original features helps build a robust model in AD/MCI classification, with high diagnostic accuracy. Furthermore, thanks to the unsupervised characteristic of the pre-training in deep learning, we can benefit from the target-unrelated samples to initialize parameters of SAE, thus finding optimal parameters in fine-tuning with the target-related samples, and further enhancing the classification performances across four binary classification problems: AD vs. healthy normal control (HC), MCI vs. HC, AD vs. MCI, and MCI converter (MCI-C) vs. MCI non-converter (MCI-NC). In our experiments on ADNI dataset, we validated the effectiveness of the proposed method, showing the accuracies of 98.8, 90.7, 83.7, and 83.3 % for AD/HC, MCI/HC, AD/MCI, and MCI-C/MCI-NC classification, respectively. We believe that deep learning can shed new light on the neuroimaging data analysis, and our work presented the applicability of this method to brain disease diagnosis.