Role of depression in predicting time to conversion to mild cognitive impairment

Exploring the Genetic Landscape of Mild Behavioral Impairment as an Early Marker of Cognitive Decline: An Updated Review Focusing on Alzheimer's Disease

The clinical features and pathophysiology of neuropsychiatric symptoms (NPSs) in dementia have been extensively studied. However, the genetic architecture and underlying neurobiological mechanisms of NPSs at preclinical stages of cognitive decline and Alzheimer's disease (AD) remain largely unknown. Mild behavioral impairment (MBI) represents an at-risk state for incident cognitive impairment and is defined by the emergence of persistent NPSs among non-demented individuals in later life. These NPSs include affective dysregulation, decreased motivation, impulse dyscontrol, abnormal perception and thought content, and social inappropriateness. Accumulating evidence has recently begun to shed more light on the genetic background of MBI, focusing on its potential association with genetic factors related to AD. The Apolipoprotein E (APOE) genotype and the MS4A locus have been associated with affective dysregulation, ZCWPW1 with social inappropriateness and psychosis, BIN1 and EPHA1 with psychosis, and NME8 with apathy. The association between MBI and polygenic risk scores (PRSs) in terms of AD dementia has been also explored. Potential implicated mechanisms include neuroinflammation, synaptic dysfunction, epigenetic modifications, oxidative stress responses, proteosomal impairment, and abnormal immune responses. In this review, we summarize and critically discuss the available evidence on the genetic background of MBI with an emphasis on AD, aiming to gain insights into the potential underlying neurobiological mechanisms, which till now remain largely unexplored. In addition, we propose future areas of research in this emerging field, with the aim to better understand the molecular pathophysiology of MBI and its genetic links with cognitive decline.

Effects of race, baseline cognition, and APOE on the association of affective dysregulation with incident dementia: A longitudinal study of dementia-free older adults

BACKGROUND

Affective symptoms are dementia risk factors. Mild behavioral impairment (MBI) is a neurobehavioral syndrome that refines incorporation of psychiatric symptomatology into dementia prognostication by stipulating symptoms must emerge de novo in later life and persist for ≥6 months. Here, we investigated the longitudinal association of MBI-affective dysregulation with incident dementia.

METHODS

National Alzheimer Coordinating Centre participants with normal cognition (NC) or mild cognitive impairment (MCI) were included. MBI-affective dysregulation was operationalized as Neuropsychiatric Inventory Questionnaire-measured depression, anxiety, and elation at two consecutive visits. Comparators had no neuropsychiatric symptoms (no NPS) in advance of dementia. Cox proportional hazard models were implemented to assess the risk of dementia, adjusted for age, sex, years of education, race, cognitive diagnosis, and APOE-ε4 status, with interaction terms as appropriate.

RESULTS

The final sample included 3698 no-NPS (age:72.8; 62.7 % female), and 1286 MBI-affective dysregulation participants (age:75; 54.5 % female). MBI-affective dysregulation had lower dementia-free survival (p < 0.0001) and greater incidence of dementia (HR = 1.76, CI:1.48-2.08, p < 0.001) versus no NPS. Interaction analyses revealed that MBI-affective dysregulation was associated with higher dementia incidence in Black participants than White (HR = 1.70, CI:1.00-2.87, p = 0.046), NC than MCI (HR = 1.73, CI:1.21-2.48, p = 0.0028), and APOE-ε4 noncarriers than carriers (HR = 1.47, CI:1.06-2.02, p = 0.0195). Of MBI-affective dysregulation converters to dementia, 85.5 % developed Alzheimer's disease, which increased to 91.4 % in those with amnestic MCI.

LIMITATIONS

MBI-affective dysregulation was not stratified by symptom to further examine dementia risk.

CONCLUSIONS

Emergent and persistent affective dysregulation in dementia-free older adults is associated with substantial risk for dementia and should be considered in clinical assessments.

Predictors of Incident Mild Cognitive Impairment and Its Course in a Diverse Community-Based Population

BACKGROUND AND OBJECTIVES

To investigate sociodemographic and medical predictors of incident mild cognitive impairment (MCI) and subsequent course of MCI at follow-up, including sustained MCI diagnosis, classification as cognitively normal, and progression to dementia.

METHODS

Within a community-based cohort, diagnoses of MCI were made with a published algorithm. Diagnosis of dementia was based on clinical consensus. Cox regressions estimated hazard ratios of incident MCI associated with several predictors. Modified Poisson regressions estimated relative risks associated with predictors of diagnostic status at follow-up after incidence.

RESULTS

Among 2,903 cognitively normal participants at baseline, 752 developed MCI over an average of 6.3 (SD 4.5) years (incidence rate 56 per 1,000 person-years). Presence of APOE ε4 and higher medical burden increased risk of incident MCI, while more years of education, more leisure activities, and higher income decreased this risk. Of the incident MCI cases, after an average of 2.4 years of follow-up, 12.9% progressed to dementia, 9.6% declined in functioning and did not meet the algorithmic criteria for MCI but did not meet the clinical criteria for dementia, 29.6% continued to meet MCI criteria, and 47.9% no longer met MCI criteria. Multidomain MCI, presence of APOE ε4, depressive symptoms, and antidepressant use increased the risk of progression to dementia.

DISCUSSION

This community-based study showed that almost half of the individuals with incident MCI diagnoses were classified as cognitively normal at follow-up. Predictors of incident MCI demonstrably differed from those of subsequent MCI course; these findings can refine expectations for cognitive and functional course of those presenting with MCI.

Changes in oral and cognitive functions among older Japanese dental outpatients: A 2-year follow-up study

BACKGROUND

The relationship between oral and cognitive functions among older people is highly debated.

OBJECTIVE

To examine whether oral functions are related to changes in the levels of mild cognitive impairment (MCI) biomarkers in older Japanese outpatients.

METHODS

This observational study included 52 outpatients aged ≥65 years who underwent dental examinations at the Fukuoka Dental College Hospital. The Mini-Mental State Examination (MMSE) was performed, and MCI blood biomarker levels were assessed at baseline and after 2 years. The present dental and periodontal conditions and the oral functions (tongue pressure and masticatory performance) were evaluated. Changes in parameters from baseline to follow-up were compared using the Wilcoxon signed-rank test, McNemar test or chi-squared test. Associations among changes in the parameters were analysed using Spearman's rank correlation coefficient.

RESULTS

The follow-up rate in this study was 67%. The masticatory performance was improved (p < 0.001), whereas gingival inflammation was decreased (p < 0.001) over the 2-year period. A significant increase in the MMSE score (p < 0.001) and a decrease in MCI risk (p < 0.001) were noted. The decrease in MCI risk was correlated with the increase in both masticatory performance (ρ = -0.34; p < 0.05) and MMSE score (ρ = -0.56; p < 0.01).

CONCLUSION

A decrease in MCI risk, as demonstrated by the levels of the blood biomarkers, was correlated with an increase in the masticatory performance in Japanese outpatients.

Depression and Cognitive Impairment in Institutionalized Older Adults

BACKGROUND

In the last three decades, the relationship between depression and cognition in geriatric patients has been a popular topic among researchers and clinicians. Clinical and epidemiological research has focused on the identification of risk factors that could be modified in pre-dementia syndromes, at a preclinical and early clinical stage of dementia disorders, with specific attention to the role of depression. The objective of this work was to determine the relationship between depressive disorder and cognitive deterioration in institutionalized older adults.

METHODS

In this descriptive, correlational study, data were gathered from two nursing homes in the province of Jaen (Spain), from a random sample of 140 older adults (70 nondependent and 70 dependent). The variables were measured using comprehensive geriatric assessment, the Cambridge Cognitive Test (CAMCOG), and the Geriatric Depression Scale (GDS).

RESULTS

Depression was correlated with cognitive level in the nondependent older adult sample (r = -0.471, p = 0.004). Age was inversely associated with the score obtained in the CAMCOG of the nondependent older adult sample (r = -0.352, p = 0.038). The functional capacity in several activities of daily living was correlated with the score obtained in the CAMCOG in each of the two groups. Depression was more prevalent in the dependent than in the nondependent older adults (82.85 vs. 57.14%). No association was observed between institutionalization time and the score obtained on the cognitive and affective scales (GDS and CAMCOG) in both groups (GDS-nondependent, r = -0.209, p = 0.234; CAMCOG-nondependent, r = 0.007, p = 0.967; GDS-dependent, r = 0.251, p = 0.152; CAMCOG-dependent, r = -0.021, p = 0.907).

CONCLUSION

Depressive symptomatology is associated with cognitive deterioration. Depression is prevalent in institutions that care for older, more dependent adults.

The Relationship Between Depression and Cognitive Deterioration in Elderly Persons

Abstract The objective of this research is to describe the relationship between depressive disorder and cognitive deterioration in residentialized elderly people. This is a descriptive and correlational study with 70 elderly. The variables have been assessed with a Psychosocial Variables Questionnaire, CAMCOG and GDS. Depression was significantly correlated with cognitive level in the non-assisted elderly sample (r=0.471, p=0.004). Participants’ age is negatively associated with the score obtained in the CAMCOG of non-assisted sample (r=-0.352, p=0.038). Depression is more frequent in institutions that care for older people when they are more dependent.

The Effect of Cognitive Impairment on the Prognosis of Major Depressive Disorder

The study recruited 168 patients diagnosed with major depressive disorder (MDD). The nine-item Patient Health Questionnaire (PHQ-9) and Perceived Deficits Questionnaire for Depression (PDQ-D) were lower and the Digit Symbol Substitution Test (DSST) was higher in the community volunteers than those in MDD patients. Depression-related scores (17-item Hamilton Depression Rating Scale [HAMD-17], Clinical Global Impressions-Severity of Illness Scale [CGI-S], and PHQ-9), functioning-related scores (Sheehan Disability Scale [SDS]), and Work Efficiency and Activity Damage-Specific Health Problems questionnaire work productivity loss were decreased, and the quality of life-related scores (European Quality of life-5 Dimensions [EQ-5D] utility score) were increased in the MDD patients. PDQ-D was decreased and DSST was increased with the increase of follow-up time. Linear regression indicated that cognitive symptoms (PDQ-D and DSST) improved more slowly than depressive symptoms (PHQ-9). At baseline, PDQ-D was related with functioning (SDS and work productivity loss). PDQ-D and DSST were related with EQ-5D utility score. In addition, at month 6, PDQ-D was related with functioning (SDS and work productivity loss) and EQ-5D utility score. Cognitive impairment might be a risk for MDD and MDD-related changes in the functioning and quality of life.

Behavioral and Psychological Symptoms that Predict Cognitive Decline or Impairment in Cognitively Normal Middle-Aged or Older Adults: a Meta-Analysis

Epidemiological studies have revealed that behavioral and psychological (or non-cognitive) symptoms are risk factors for cognitive decline in older adults. This study aimed to systematically review the literature and determine which behavioral and psychological symptoms are most predictive of future cognitive decline among individuals with no pre-existing cognitive impairments. The selected studies included middle-aged or older adults without cognitive impairments. The predictors were assessed using behavioral and psychological questionnaires, or diagnostic interviews, to identify non-cognitive symptoms or psychiatric clinical conditions. The follow-up period was at least one year, and the design of the selected studies was either retrospective or prospective. This study compared individuals with and without non-cognitive manifestations and resulted in one of three outcomes: (a) a score change on a cognitive measure, (b) a diagnosis of mild cognitive impairment, or (c) a diagnosis of Alzheimer's disease or dementia. Four online databases were searched for eligible studies from the database inception to January 17, 2017: MEDLINE (PubMed), Embase (OVID), PsycINFO, and Web of Science. Pooled effect sizes were estimated using a random-effect model. Higgins I², the Q statistic, and tau-squared were used to quantify the observed heterogeneity between the studies. Results indicate that depression and sleep duration (long and short) were the most consistent associations between behavioral or psychological symptoms and cognitive decline. This meta-analysis supports the need to assess behavioral and psychological symptoms in cognitively intact older adults to identify those who are at risk for cognitive decline.

Predicting Hepatic Encephalopathy-Related Hospitalizations Using a Composite Assessment of Cognitive Impairment and Frailty in 355 Patients With Cirrhosis

INTRODUCTION

Hepatic encephalopathy (HE) is the most common potentially modifiable reason for admission in patients with cirrhosis. Cognitive and physical components of frailty have pathophysiologic rationale as risk factors for HE. We aimed to assess the utility of a composite score (MoCA-CFS) developed using the Montreal Cognitive Assessment (MoCA) and the Clinical Frailty Scale (CFS) for predicting HE admissions within 6 months.

METHODS

Consecutive adult patients with cirrhosis were followed for 6 months or until death/transplant. Patients with overt HE and dementia were excluded. Primary outcome was the prediction of HE-related admissions at 6 months.

RESULTS

A total of 355 patients were included; mean age 55.9 ± 9.6; 62.5% male; Hepatitis C and alcohol etiology in 64%. Thirty-six percent of patients had cognitive impairment according to the MoCA (≤24) and 14% were frail on the CFS (>4). The MoCA-CFS independently predicted HE hospitalization within 6 months, a MoCA-CFS score of 1 and 2 respectively increasing the odds of hospitalization by 3.3 (95% CI:1.5-7.7) and 5.7 (95% CI:1.9-17.3). HRQoL decreased with increasing MoCA-CFS. Depression and older age were independent predictors of a low MoCA.

CONCLUSIONS

Cognitive and physical frailty are common in patients with cirrhosis. In addition to being an independent predictor of HE admissions within 6 months, the MoCA-CFS composite score predicts impaired HRQoL and all-cause admissions within 6 months. These data support the predictive value of a "multidimensional" frailty tool for the prediction of adverse clinical outcomes and highlight the potential for a multi-faceted approach to therapy targeting cognitive impairment, physical frailty and depression.

The Impact of Depression on the Development of Mild Cognitive Impairment over 3 Years of Follow-Up: A Population-Based Study

BACKGROUND/AIMS

In the absence of effective treatments for dementia, major efforts are being directed towards identifying the risk factors of the prodromal phase of the disease. We report the incidence rates of mild cognitive impairment (MCI) in a Spanish population sample and assess the effect of depression at baseline on incident MCI (or MCI subtypes) at a 3-year follow-up.

METHODS

A total of 1,642 participants (age ≥50 years) were examined as part of a Spanish nationally representative longitudinal study. MCI was defined as the presence of cognitive concerns, objective evidence of impairment in one or more cognitive domains, preservation of independence in functional abilities, and no dementia. Depression was assessed through an adaptation of the Composite International Diagnostic Interview (CIDI 3.0). Binary and multinomial logistic regression analyses were carried out to assess the associations.

RESULTS

The overall MCI incidence rate was 33.19 (95% CI = 26.02, 43.04) per 1,000 person-years. Depression at baseline predicted the onset of MCI at follow-up after controlling for sociodemographics, cognitive functioning, and other physical health conditions (OR = 2.79; 95% CI = 1.70, 4.59). The effect of baseline depression on incident MCI subtypes was as follows: amnestic MCI, OR = 3.81 (95% CI = 1.96, 7.43); nonamnestic MCI, OR = 2.03 (95% CI = 0.98, 4.21).

CONCLUSION

Depression significantly increases the risk for MCI. Targeting depression among those at risk for dementia may help delay or even prevent the onset of dementia.

Dementia Prevalence in a Rural Region of South Africa: A Cross-Sectional Community Study

BACKGROUND

Dementia is a growing concern for low- and middle-income countries where longevity is increasing and service provision is poor. Global prevalence estimates vary from 2% to 8.5% for those aged 60 years and older. There have been few dementia studies in sub-Saharan Africa, and prevalence data are lacking for South Africa.

OBJECTIVE

To conduct a large dementia prevalence study in a low income rural population in South Africa.

METHODS

1,394 Xhosa-speaking community dwellers, aged ≥60 y (mean age±sd 71.3±8.3 y), in three clinic catchment areas, were screened at home. Trained community health workers administered the brief Community Screening Instrument for Dementia (CSID) to participants and informants to assess cognitive and functional capacity. Depressive symptoms were assessed with three questions from the EURO-D.

RESULTS

The prevalence estimate using published CSID sensitivity/specificity values was 0.8 (95% CI: 0.06-0.09). Using CSID cut-off scores the estimated prevalence was 0.12 (95% CI: 0.10-0.13), with 161 screen-positives. Both methods gave a rate of 0.11 (95% CI: 0.09-0.13) for those over 65 years (n = 1051). 68.6% of participants were female and 69.8% had less than 7 years of education. Dementia risk was associated with older age and symptoms of depression, but not with sex. The association with education was not significant when controlled for by age.

CONCLUSIONS

Dementia prevalence estimates were higher than expected for this low-income rural community. There is a need for increased dementia awareness and feasible support interventions. We also need further studies of regional prevalences, dementia subtypes, and modifiable risk factors in South Africa.

Gene-behavior interaction of depressive symptoms and the apolipoprotein E {varepsilon}4 allele on cognitive decline

OBJECTIVE

Depressive symptoms and the apolipoprotein E (APOE) ε4 allele are independent risk factors for cognitive decline. However, it is not clear whether the presence of both depressive symptoms and the APOE ε4 allele increases cognitive decline.

METHODS

A prospective study of a population-based sample of 4150 (70% African American and 63% women) participants 65 years and older who were interviewed at 3-year intervals was conducted. Depressive symptoms were measured using the 10-item version of the Center for Epidemiologic Studies Depression scale, with each item coded as presence or absence of a symptom. The APOE genotype was ascertained by DNA samples collected during follow-up. Cognitive function was assessed at the initial and follow-up interviews (average follow-up of 9.2 years), using a standardized global cognitive score.

RESULTS

There were 1405 (34%) participants with one or more copies of the APOE ε4 allele. In participants with no depressive symptoms, cognitive function decreased by 0.0412 unit per year among those with no copies and 0.0704 unit per year among those with one or more copies of the APOE ε4 allele. For each additional symptom of depression, cognitive decline increased by 0.0021 unit per year among those with no copies and 0.0051 unit per year among those with one or more copies of the APOE ε4 allele. The three-way interaction of depressive symptoms, APOE ε4 allele, and time was significant (p = .021).

CONCLUSIONS

The association of depressive symptoms on cognitive decline was increased among participants with one or more copies of the APOE ε4 allele compared with those without the allele.