Lifestyle Factors Are Important Contributors to Subjective Memory Complaints among Patients without Objective Memory Impairment or Positive Neurochemical Biomarkers for Alzheimer's Disease

Decoding cognitive health using machine learning: A comprehensive evaluation for diagnosis of significant memory concern

The timely identification of significant memory concern (SMC) is crucial for proactive cognitive health management, especially in an aging population. Detecting SMC early enables timely intervention and personalized care, potentially slowing cognitive disorder progression. This study presents a state‐of‐the‐art review followed by a comprehensive evaluation of machine learning models within the randomized neural networks (RNNs) and hyperplane‐based classifiers (HbCs) family to investigate SMC diagnosis thoroughly. Utilizing the Alzheimer's Disease Neuroimaging Initiative 2 (ADNI2) dataset, 111 individuals with SMC and 111 healthy older adults are analyzed based on T1W magnetic resonance imaging (MRI) scans, extracting rich features. This analysis is based on baseline structural MRI (sMRI) scans, extracting rich features from gray matter (GM), white matter (WM), Jacobian determinant (JD), and cortical thickness (CT) measurements. In RNNs, deep random vector functional link (dRVFL) and ensemble dRVFL (edRVFL) emerge as the best classifiers in terms of performance metrics in the identification of SMC. In HbCs, Kernelized pinball general twin support vector machine (Pin‐GTSVM‐K) excels in CT and WM features, whereas Linear Pin‐GTSVM (Pin‐GTSVM‐L) and Linear intuitionistic fuzzy TSVM (IFTSVM‐L) performs well in the JD and GM features sets, respectively. This comprehensive evaluation emphasizes the critical role of feature selection, feature  based‐interpretability and model choice in attaining an effective classifier for SMC diagnosis. The inclusion of statistical analyses further reinforces the credibility of the results, affirming the rigor of this analysis. The performance measures exhibit the suitability of this framework in aiding researchers with the automated and accurate assessment of SMC. The source codes of the algorithms and datasets used in this study are available at https://github.com/mtanveer1/SMC.

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Objectifying subjective memory complaints: VR-based Verbal Word Learning Test in chronic stroke patients

Memory impairment imposes a great burden on stroke patients and can be divided into Objective Memory Problems (OMPs) and Subjective Memory Complaints (SMCs). Studies have shown that these do not always co-occur. Possibly, the gap between SMCs and OMPs can be bridged when using a more ecologically valid memory test and considering the impact of other common stroke symptoms such as sensory hypersensitivity (SHS) and fatigue. In the present study, we applied Virtual Reality (VR) to create a sensory-rich environment with real-life stimuli. Memory performance was tested with the 15-Verbal Word Learning Test (VLT). Furthermore, we assessed SMCs (Everyday Memory Questionnaire), and the levels of SHS (Multi-Modal Evaluation of Sensory Sensitivity) and fatigue in the previous month. 31 chronic stroke patients and 32 healthy controls participated. The results showed that participants' memory performance decreased in a sensory-rich compared to a neutral environment. This decrease did not significantly differ between the groups. Interestingly, fatigue and SHS are related to the level of SMC in stroke patients but no such evidence was found in healthy controls. Last, for stroke patients, we found a significant negative correlation between SMCs and memory performance in a sensory-rich environment, but not in a neutral environment. In conclusion, our study implicates that in stroke patients, fatigue and SHS are related to SMCs and that using a sensory-rich VR environment might be a more ecologically valid way to objectify SMCs. However, interpretative caution is warranted due to the absence of sex and age-matched controls and potential selection bias.

Examining racial differences in the network structure and properties of specific cognitive domains among older adults

Older adults oftentimes experience cognitive aging which leads to varying degrees of cognitive impairment. Previous studies have found that racial and ethnic disparities exist in the prevalence and severity of cognitive impairment among older adults. Yet, little is known on the relationship among specific cognitive domains and how this relationship differs between African American and White older adults. This is a secondary data analysis of Wave II (2010-2011) data from the National Social Life, Health, and Aging Project (NSHAP). A total of 2,471 older adults aged between 65 and 85 years old (African American n = 452, White n = 2019) were included. Network analysis was used to visualize and characterize the network structure and to examine network stability. Then, network comparison test was conducted to compare the network properties of the cognitive network structure between African American and White older adults. African American older adults had a lower cognitive function in all cognitive domains than White older adults. While there was no significant difference in global strength, there was a significant difference in the network structure and strength centrality measure between the two groups (p < 0.05). The invariance edge strength test found the language-visuospatial edge to be significantly stronger in African American older adults. Clinicians need to understand the different cognitive function across multiple cognitive domains between African American and White older adults and routinely offer targeted and timely cognitive assessment and management in this population.

Prevalence and Factors Associated with Subjective Memory Complaint in a Semi-Rural Community in Chile

BACKGROUND

Subjective memory complaints (SMC) are commonly studied in older adults and have been identified as potentially prodromal to dementia and Alzheimer's disease. Studies among younger adults from South America are lacking.

OBJECTIVE

To estimate the prevalence of SMC and the factors associated with it among Maule Cohort (MAUCO) participants.

METHODS

We performed a cross-sectional analysis to estimate the prevalence of SMC and investigated its associated factors from MAUCO baseline data (N = 6,687). Within groups defined by age (38-59, 60-74) and global cognition (Mini-Mental State Examination: ≥26, 25-22, ≤21), multinomial logistic regression models evaluated risk factors for SMC (Yes, Sometimes, No).

RESULTS

Overall, SMC prevalence was 16.4%; 15.9% (95% CI 14.9-16.9%) among younger and 17.6% (15.8-19.4%) among older participants. Female sex, comorbidities, and bad/fair self-reported health status (SRHS) were generally associated with higher odds of SMC.

CONCLUSION

Overall prevalence of SMC was 16%. Different factors were associated with the odds of SMC depending on age and global cognitive status. Future SMC studies should include sex-specific assessments, evaluate SRHS as a moderator of SMC reporting, and the influence of the SARS-CoV-2 pandemic on SMC reporting.

Common Neuropsychiatric S ymptoms in Alzheimer's Disease, Mild Cognitive Impairment, and Subjective Memory Complaints: A Unified Framework

The Alzheimer's disease (AD) continuum is a unique spectrum of cognitive impairment that typically involves the stages of subjective memory complaints (SMC), mild cognitive impairment (MCI), and AD dementia. Neuropsychiatric symptoms (NPS), such as apathy, anxiety, stress, and depression, are highly common throughout the AD continuum. However, there is a dearth of research on how these NPS vary across the AD continuum, especially SMC. There is also disagreement on the effects of specific NPS on each stage of the AD continuum due to their collinearity with other NPS, cognitive decline, and environmental factors (e.g., stress). In this article, we conduct a novel perspective review of the scientific literature to understand the presence of NPS across the AD continuum. Specifically, we review the effects of apathy, depression, anxiety, and stress in AD, MCI, and SMC. We then build on this knowledge by proposing two theories of NPS' occurrence across the AD continuum. Consequently, we highlight the current landscape, limitations (e.g., differing operationalization), and contentions surrounding the NPS literature. We also outline theories that could clear up contention and inspire future NPS research.

Earlier Detection of Alzheimer's Disease Based on a Novel Biomarker cis P-tau by a Label-Free Electrochemical Immunosensor

Early detection of cis phosphorylated tau (cis P-tau) may help as an effective treatment to control the progression of Alzheimer's disease (AD). Recently, we introduced for the first time a monoclonal antibody (mAb) with high affinity against cis P-tau. In this study, the cis P-tau mAb was utilized to develop a label-free immunosensor. The antibody was immobilized onto a gold electrode and the electrochemical responses to the analyte were acquired by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and differential pulse voltammetry (DPV). The immunosensor was capable of selective detection of cis P-tau among non-specific targets like trans P-tau and major plasma proteins. A wide concentration range (10 × 10^-14 M-3.0 × 10^-9 M) of cis P-tau was measured in PBS and human serum matrices with a limit of detection of 0.02 and 0.05 pM, respectively. Clinical applicability of the immunosensor was suggested by its long-term storage stability and successful detection of cis P-tau in real samples of cerebrospinal fluid (CSF) and blood serum collected from human patients at different stages of AD. These results suggest that this simple immunosensor may find great application in clinical settings for early detection of AD which is an unmet urgent need in today's healthcare services.

Subjective cognitive decline and self-reported sleep problems: The SCIENCe project

We aim to investigate the frequency and type of sleep problems in memory clinic patients with subjective cognitive decline (SCD) and their association with cognition, mental health, brain magnetic resonance imaging (MRI), and cerebrospinal fluid (CSF) biomarkers. Three hundred eight subjects (65 ± 8 years, 44% female) were selected from the Subjective Cognitive Impairment Cohort (SCIENCe) project. All subjects answered two sleep questionnaires, Berlin Questionnaire (sleep apnea) and Pittsburgh Sleep Quality Index (sleep quality) and underwent a standardized memory clinic work-up. One hundred ninety-eight (64%) subjects reported sleep problems, based on 107 (35%) positive screenings on sleep apnea and 162 (53%) on poor sleep quality. Subjects with sleep problems reported more severe depressive symptoms, more anxiety, and more severe SCD. Cognitive tests, MRI, and CSF biomarkers did not differ between groups. Our results suggest that improvement of sleep quality and behaviors are potential leads for treatment in many subjects with SCD to relieve the experienced cognitive complaints.

OUP accepted manuscript

OBJECTIVE

The etiology of persistent memory complaints after concussion is poorly understood. Memory perfectionism (highly valuing memory ability and intolerance of minor memory lapses) may help explain why some people report persistent subjective memory problems in the absence of corresponding objective memory impairment. This study investigated the relationship between memory perfectionism and persistent memory complaints after concussion.

METHODS

Secondary analysis of baseline data from a randomized controlled trial. Adults (N = 77; 61% women) with persistent symptoms following concussion were recruited from outpatient specialty clinics. Participants completed the National Institutes of Health Toolbox Cognition Battery, Test of Memory Malingering-Trial 1, and questionnaires measuring memory perfectionism (Metamemory in Adulthood-Achievement subscale), forgetfulness and other postconcussion symptoms (Rivermead Postconcussion Symptoms Questionnaire; RPQ), and depression (Patient Health Questionnaire-2) at M = 17.8 weeks postinjury. Patients with versus without severe memory complaints (based on the RPQ) were compared.

RESULTS

Memory perfectionism was associated cross-sectionally with severe memory complaint, after controlling for objective memory ability, overall cognitive ability, and depression (95% confidence interval for odds ratio = 1.11-1.40). Sensitivity analyses showed that this relationship did not depend on use of specific objective memory tests nor on inclusion of participants who failed performance validity testing. In a control comparison to test the specificity of identified relationships, memory perfectionism was not associated with severe fatigue (95% confidence interval for odds ratio = 0.91-1.07).

CONCLUSIONS

Memory perfectionism may be a risk factor for persistent memory symptoms after concussion, with potential relevance to the spectrum of functional cognitive disorders more broadly.

Are there differences in symptoms experienced by midlife climacteric women with and without metabolic syndrome? A scoping review

INTRODUCTION

Midlife climacteric women with metabolic syndrome are at high risk for experiencing a complex array of symptoms. The aim of this scoping review was to identify the prevalence, types, and clustering of symptoms in midlife climacteric women with metabolic syndrome and to compare them to symptoms of midlife climacteric women without metabolic syndrome.

METHODS

A three-step search method was used according to Joanna Briggs Institute methodology. Eligibility criteria of participants, concept, context, and types of evidence were selected in alignment with the review questions. Seven databases (PubMed, Embase, Web of Science, CINAHL, PsycINFO, ProQuest Dissertation & Theses, OpenGrey) were searched using search terms with no language or date restrictions. Title and abstract screening, full-text review, data charting, and data synthesis were conducted by two independent researchers based on the eligibility criteria.

RESULTS

The search yielded 3813 studies after removing duplicates with 48 full-text papers assessed for eligibility. A total of eight studies were reviewed and analyzed which reported the prevalence and types of symptoms individually or grouped based on each body system. Midlife climacteric women with metabolic syndrome experience a wide prevalence of individual and grouped urogenital, vasomotor, psychological, sleep, and somatic symptoms. Mental exhaustion had the highest prevalence (84.4%) among the individual symptoms, and urogenital symptoms had the highest prevalence (81.3%) among the grouped symptoms. There were mixed findings on symptoms between midlife climacteric women with metabolic syndrome and without metabolic syndrome. No studies focused on symptom clusters.

CONCLUSION

Our findings will serve as a knowledge basis for understanding symptoms experienced by midlife climacteric women with metabolic syndrome. This new knowledge can assist clinicians in effectively assessing and managing their symptoms in clinical settings and inform future development of targeted symptom management interventions.

The Relationship Between Perceived Stress and Subjective Cognitive Decline During the COVID-19 Epidemic

During the outbreak of the COVID-19 epidemic, fear of disease and its consequences, recommended lifestyle changes, and severe restrictions set by governments acted as stressors and affected people's mood, emotions, mental health, and wellbeing. Many studies conducted during this crisis focused on affective and physiological responses to stress, but few studies examined how the crisis affected cognition. The present cross-sectional study examined the relationship between physiological, affective, and cognitive responses to the epidemic. In an online survey conducted at the height of the first wave of the epidemic in Slovenia (April 15-25, 2020), 830 Slovenian residents aged 18-85 years reported the effects of stressors (confinement, problems at home, problems at work, lack of necessities, and increased workload), experienced emotions, generalized anxiety, perceived stress, changes in health, fatigue and sleep quality, and perceived changes in cognition during the epidemic. Risk factors for stress (neuroticism, vulnerability, general health, gender, and age) were also recorded. We hypothesized that stressors and stress risk factors will be related to subjective cognitive decline, with negative emotions, generalized anxiety, perceived stress, and physical symptoms acting as mediator variables. On average, the results showed a mild subjective cognitive decline during the epidemic. In structural equation modeling, 34% of its variance was predicted by the mediator variables, with negative emotions and physical symptoms having the largest contribution. Stress risk factors were predictably related to the four mediator variables. Among the stressors, confinement showed the strongest effect on the four mediator variables, implying the importance of thoughtful communication about necessary restrictive measures during emergency circumstances. The results of this study indicate that the possibility of altered cognitive function should be considered when planning work and study activities during the epidemic.

Physical and Mental Health Characteristics of 2,962 Adults With Subjective Cognitive Complaints

We investigated subjective cognitive complaints (SCCs), as well as physical and mental health factors, in adults and older adults. U.S. residents (N = 2,962) were recruited via the Amazon Mechanical Turk platform and completed a 90-item survey. Overall, 493/1930 (25.5%) of younger adults and 278/1032 (26.9%) of older adults endorsed SCCs. Analyses revealed worse physical and mental health characteristics in the SCC+ compared to the SCC- group, with primarily medium (Cohen's d = 0.50) to large (0.80) effect sizes. Age did not moderate relationships between SCCs and physical/mental health. Results suggest that SCCs are associated with a diverse set of negative health characteristics such as poor sleep and high body mass index, and lower levels of positive factors, including happiness and wisdom. Effect sizes of psychological correlates were at least as large as those of physical correlates, indicating that mental health is critical to consider when evaluating SCCs.

Association between sexual orientation and subjective cognitive complaints in the general population in England

There is a scarcity of literature investigating the association between minority sexual orientations and subjective cognitive complaints (SCC). Therefore, the aim of this study was to investigate the association between identifying as a sexual minority and SCC in a large sample of adults from England. The study further aimed to identify the extent to which the association could be explained by several behavioral, psychological and clinical factors. Cross-sectional data from the 2007 Adult Psychiatric Morbidity Survey (APMS) were analyzed. Sexual orientation was dichotomized into heterosexual and sexual minority orientation. SCC referred to subjective concentration and memory complaints. Control variables included sex, age, ethnicity, marital status, education, employment, and income. Influential factors included smoking status, alcohol dependence, perceived stress, the number of stressful life events, depression, any anxiety disorder, sleep problems, and obesity. This study included 7,400 participants (51.4% women; mean [standard deviation] age 46.3 [18.6] years). After adjusting for control variables, sexual minority orientation was positively and significantly associated with subjective concentration (OR = 1.40, 95% CI = 1.12-1.76) but not memory complaints (OR = 1.19, 95% CI = 0.96-1.47). The number of stressful life events, sleep problems and any anxiety disorder explained 13.4%, 11.0% and 10.9% of the association between sexual orientation and subjective concentration complaints, respectively. In this large sample of English adults, identifying as a sexual minority was significantly associated with subjective concentration complaints, while stressful life events, sleep problems, and anxiety explained a large proportion of the association. Targeted interventions towards sexual minority groups to reduce SCC may be warranted.

Association of subjective memory complaints amid patients of Diabetes Mellitus Type II and Hypertension

Background and Objective

Subjective memory complaints (SMCs) are suggested to predict dementia at a very early stage. However, association of SMCs with known risk factors of dementia namely diabetes mellitus Type-2 diabetes and hypertension (HTN) remain unexplored which is the main aim of this study. The objective of the study was to investigate the association of SMC with diabetes mellitus type 2 (DM2) and hypertension (HTN).

Methods

The associations of diabetes and hypertension, with SMCs has been tested in 500 participants from a tertiary care hospital of Karachi during 2017. Diagnosed cases of diabetes and hypertension were included through convenient sampling. Healthy attendants of patients were interviewed for the reference group. SMCs were assessed through a 14-item SMC questionnaire.

Results

Sample included 114 patients with only diabetes and hypertension each, 103 with both diabetes and hypertension and 169 healthy participants. Compared to healthy adults, persons with diabetes and hypertension had higher SMCs (difference, 0.88, 95% CI: 0.22, 1.54) (difference, 1.06, 95% CI: 0.40, 1.71) respectively, in fully adjusted models.

Conclusions

Compared to healthy adults of working age-group, persons with diabetes and hypertension were more likely to have SMCs. Assessment and early detection of SMCs in persons with diabetes and hypertension might be informative to provide a window for effective interventions to maintain cognitive health.

Are neuropsychiatric symptoms in dementia linked to CSF biomarkers of synaptic and axonal degeneration?

Background

The underlying disease mechanism of neuropsychiatric symptoms (NPS) in dementia remains unclear. Cerebrospinal fluid (CSF) biomarkers for synaptic and axonal degeneration may provide novel neuropathological information for their occurrence. The aim was to investigate the relationship between NPS and CSF biomarkers for synaptic (neurogranin [Ng], growth-associated protein 43 [GAP-43]) and axonal (neurofilament light [NFL]) injury in patients with dementia.

Methods

A total of 151 patients (mean age ± SD, 73.5 ± 11.0, females n = 92 [61%]) were included, of which 64 had Alzheimer’s disease (AD) (34 with high NPS, i.e., Neuropsychiatric Inventory (NPI) score > 10 and 30 with low levels of NPS) and 18 were diagnosed with vascular dementia (VaD), 27 with mixed dementia (MIX), 12 with mild cognitive impairment (MCI), and 30 with subjective cognitive impairment (SCI). NPS were primarily assessed using the NPI. CSF samples were analyzed using enzyme-linked immunosorbent assays (ELISAs) for T-tau, P-tau, Aβ1–42, Ng, NFL, and GAP-43.

Results

No significant differences were seen in the CSF levels of Ng, GAP-43, and NFL between AD patients with high vs low levels of NPS (but almost significantly decreased for Ng in AD patients < 70 years with high NPS, p = 0.06). No significant associations between NPS and CSF biomarkers were seen in AD patients. In VaD (n = 17), negative correlations were found between GAP-43, Ng, NFL, and NPS.

Conclusion

Our results could suggest that low levels of Ng may be associated with higher severity of NPS early in the AD continuum (age < 70). Furthermore, our data may indicate a potential relationship between the presence of NPS and synaptic as well as axonal degeneration in the setting of VaD pathology.

Lifestyle Factors and Subjective Cognitive Impairment in Patients Seeking Help at a Memory Disorder Clinic: The Role of Negative Life Events

BACKGROUND/AIMS

A large proportion of patients at memory disorders clinics are classified as having subjective cognitive impairment (SCI). Previous research has investigated whether particular lifestyle factors known to affect cognition can be useful in differentiating patients who do not show objective evidence of memory decline. There may also exist subgroups of patients with respect to lifestyle factors that could help clinicians to understand the patient group that presents to memory clinics. These may differ in diagnostic outcome. Very little is known about potential subgroups; however, but such information may help guide interventions and potentially eliminate unnecessary diagnostic procedures. The current study investigated patterns of lifestyle-related variables, including stress, sleep, sensory sensitivity, depression, and negative life events in patients presenting to a memory disorders clinic. The aim was to determine whether subgroups existed and whether it was possible to distinguish those with objectively impaired cognition.

METHODS

One hundred and seventy-eight patients (mean age 58 years) from a University Hospital Memory Disorders Clinic.

RESULTS

Cluster analysis identified three groups of lifestyle-related variables. Strong determinants of clusters were negative life events and age. Patients with a high number of negative life events also tended to have highest self-reported memory complaint, higher levels of stress, depression, and sensory sensitivity. However, they did not perform the worst on memory testing. In contrast, individuals who performed the worst on memory tests were older, tended to have the least memory complaints, and less negative lifestyle factors; this group also included the highest proportion of patients with mild cognitive impairment and had the lowest median amyloid A-beta 42 (Aβ42). The group with the best cognitive performance were younger, included the highest proportion of patients with SCI and the highest median Aβ42. On lifestyle variables, their ratings fell in between the other groups.

CONCLUSIONS

Lifestyle subgroups of patients were determined by stress, emotional problems, and age. The groups were significantly associated with Aβ42 and diagnostic outcome. This pattern may confound the differentiation between objective and subjective memory problems. Asking about lifestyle variables, in conjunction with neuropsychological testing, could potentially identify individuals who are not likely to have objective memory impairment and guide interventions.

Lifestyle Variables Do Not Predict Subjective Memory Performance Over and Above Depression and Anxiety

The diagnostic value of subjective cognitive complaints for cognitive functioning in a clinical setting remains unresolved today. However, consensus exists on the relation between subjective cognitive complaints (SCC) and mood variables such as anxiety and depression. Hence, SCC have also been discussed as potential proxies of psychopathology rather than representing cognitive functioning. In order to shed more light on yet still unexplained variance in subjective cognitive complaints, the relation between lifestyle variables (such as nutrition habits, exercise, alcohol consumption, smoking, quality of sleep, and Body Mass Index) and subjective complaints of selective attention as well as subjective memory performance were assessed, additionally to the influence of objective memory performance, measures of anxiety, and depression. A sample of 877 (554 women) healthy, middle-aged individuals (51 years on average, age range 35–65) was assessed in the present study. In a logistic regression framework results revealed that the effect of lifestyle variables on subjective complaints of selective attention as well as subjective memory performance was rendered non-significant. Instead, subjective complaints of selective attention and subjective memory performance were significantly determined by measures of both, anxiety and depression. One unit increase in anxiety or depression led to an increase of 6 or 15% in subjective memory performance complaints, respectively. For subjective complaints of selective attention, a one unit increase in anxiety or depression led to an increase of 11 or 26%, respectively. The strong relation between SCC and measures of depression and anxiety corroborates the notion of SCC being indicative of mental health and general well-being.

Functional cognitive disorders: a systematic review

Cognitive symptoms are common, and yet many who seek help for cognitive symptoms neither have, nor go on to develop, dementia. A proportion of these people are likely to have functional cognitive disorders, a subtype of functional neurological disorders, in which cognitive symptoms are present, associated with distress or disability, but caused by functional alterations rather than degenerative brain disease or another structural lesion. In this Review, we have systematically examined the prevalence and clinical associations of functional cognitive disorders, and related phenotypes, within the wider cognitive disorder literature. Around a quarter of patients presenting to memory clinics received diagnoses that might indicate the presence of functional cognitive disorders, which were associated with affective symptoms, negative self-evaluation, negative illness perceptions, non-progressive symptom trajectories, and linguistic and behavioural differences during clinical interactions. Those with functional cognitive disorder phenotypes are at risk of iatrogenic harm because of misdiagnosis or inaccurate prediction of future decline. Further research is imperative to improve diagnosis and identify effective treatments for functional cognitive disorders, and better understanding these phenotypes will also improve the specificity of diagnoses of prodromal degenerative brain disease.

Progression to dementia in memory clinic patients with mild cognitive impairment and normal β-amyloid

Background

Determination of β-amyloid (Aβ) positivity and likelihood of underlying Alzheimer’s disease (AD) relies on dichotomous biomarker cut-off values. Individuals with mild cognitive impairment (MCI) and Aβ within the normal range may still have a substantial risk of developing dementia, primarily of Alzheimer type. Their prognosis, as well as predictors of clinical progression, are not fully understood. The aim of this study was to explore the associations of cerebrospinal fluid (CSF) biomarkers (Aβ42, total tau, phosphorylated tau) and other characteristics, including modifiable vascular factors, with the risk of progression to dementia among patients with MCI and normal CSF Aβ42.

Methods

Three hundred eighteen memory clinic patients with CSF and clinical data, and at least 1-year follow-up, were included. Patients had normal CSF Aβ42 levels based on clinical cut-offs. Cox proportional hazard models with age as time scale and adjusted for sex, education, and cognition (Mini-Mental State Examination) were used to investigate predictors of progression to dementia and Alzheimer-type dementia. Potential predictors included CSF biomarkers, cognitive performance (verbal learning and memory), apolipoprotein E (APOE) ε4 genotype, medial temporal lobe atrophy, family history of dementia, depressive symptoms, and vascular factors, including the Cardiovascular Risk Factors, Aging and Dementia (CAIDE) risk score. Predictive performance of patient characteristics was further explored with Harrell C statistic.

Results

Lower normal Aβ42 and higher total tau and phosphorylated tau were associated with higher dementia risk, and the association was not driven by Aβ42 values close to cut-off. Additional predictors included poorer cognition, APOE ε4 genotype, higher systolic blood pressure, and lower body mass index, but not the CAIDE dementia risk score. Aβ42 individually and in combination with other CSF biomarkers improved the risk prediction compared to age and cognition alone. Medial temporal lobe atrophy or vascular factors did not increase the predictive performance.

Conclusions

Possibility of underlying AD pathology and increased dementia risk should not be ruled out among MCI patients with CSF Aβ42 within the normal range. While cut-offs may be useful in clinical practice to identify high-risk individuals, personalized risk prediction tools incorporating continuous biomarkers may be preferable among individuals with intermediate risk. The role of modifiable vascular factors could be explored in this context.