Similar neurocognitive performance of adults with and without a history of parental Alzheimer's disease: a pilot study

Cognitive Functioning of Unaffected First-degree Relatives of Individuals With Late-onset Alzheimer's Disease: A Systematic Literature Review and Meta-analysis

First-degree relatives of individuals with late-onset Alzheimer's disease (LOAD) are at increased risk for developing dementia, yet the associations between family history of LOAD and cognitive dysfunction remain unclear. In this quantitative review, we provide the first meta-analysis on the cognitive profile of unaffected first-degree blood relatives of LOAD-affected individuals compared to controls without a family history of LOAD. A systematic literature search was conducted in PsycINFO, PubMed /MEDLINE, and Scopus. We fitted a three-level structural equation modeling meta-analysis to control for non-independent effect sizes. Heterogeneity and risk of publication bias were also investigated. Thirty-four studies enabled us to estimate 218 effect sizes across several cognitive domains. Overall, first-degree relatives (n = 4,086, mean age = 57.40, SD = 4.71) showed significantly inferior cognitive performance (Hedges' g = -0.16; 95% CI, -0.25 to -0.08; p < .001) compared to controls (n = 2,388, mean age = 58.43, SD = 5.69). Specifically, controls outperformed first-degree relatives in language, visuospatial and verbal long-term memory, executive functions, verbal short-term memory, and verbal IQ. Among the first-degree relatives, APOE ɛ4 carriership was associated with more significant dysfunction in cognition (g = -0.24; 95% CI, -0.38 to -0.11; p < .001) compared to non-carriers (g = -0.14; 95% CI, -0.28 to -0.01; p = .04). Cognitive test type was significantly associated with between-group differences, accounting for 65% (R23 = .6499) of the effect size heterogeneity in the fitted regression model. No evidence of publication bias was found. The current findings provide support for mild but robust cognitive dysfunction in first-degree relatives of LOAD-affected individuals that appears to be moderated by cognitive domain, cognitive test type, and APOE ɛ4.

Subclinical memory impairment in unaffected siblings of patients with dementia

Objective: Family history of dementia is a known risk factor for dementia. The cognitive performance of unaffected siblings of dementia patients has been poorly studied. We aimed to determine whether clinically unaffected siblings of dementia patients have significant cognitive impairment compared to individuals who do not have first-degree relatives with dementia. Methods: We compared the cognitive performance of 67 patients with dementia (24 males; mean age 69.5), 90 healthy siblings of those patients (34 males; mean age 61.56) and 92 healthy adults (35 males; mean age 60.96) who have no first-degree relatives with dementia. We assessed learning and memory (Rey Auditory Verbal Learning Test (RAVLT)), short-term/working memory (Digit Span) executive functions (Stroop Test) and general intelligence (Raven Progressive Matrices). Test scores were compared among three groups, with regression-based adjustments for age, sex, and education. Results: As expected, the patients with dementia were impaired in all cognitive domains. In the Sibling Group, RAVLT total learning was significantly lower compared to controls (B = -3.192, p = .005). In a subgroup analysis, compared to controls, RAVLT delayed recall was poorer in the siblings of patients with early-onset (<65 years) dementia. No significant differences were observed in other cognitive domains. Conclusion: Clinically unaffected siblings of dementia patients seem to have a selective subclinical impairment in memory encoding. This impairment seems to be more prominent in siblings of patients with early-onset dementia who also have deficits in delayed recall. Future studies are needed to determine if the observed cognitive impairment deteriorates to dementia.

Cognitive Training Program to Improve Working Memory in Older Adults with MCI

OBJECTIVES

Deficits in working memory (WM) are associated with age-related decline. We report findings from a clinical trial that examined the effectiveness of Cogmed, a computerized program that trains WM. We compare this program to a Sham condition in older adults with Mild Cognitive Impairment (MCI).

METHODS

Older adults (N = 68) living in the community were assessed. Participants reported memory impairment and met criteria for MCI, either by poor delayed memory or poor performance in other cognitive areas. The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS, Delayed Memory Index) and the Clinical Dementia Rating scale (CDR) were utilized. All presented with normal Mini Mental State Exams (MMSE) and activities of daily living (ADLs). Participants were randomized to Cogmed or a Sham computer program. Twenty-five sessions were completed over five to seven weeks. Pre, post, and follow-up measures included a battery of cognitive measures (three WM tests), a subjective memory scale, and a functional measure.

RESULTS

Both intervention groups improved over time. Cogmed significantly outperformed Sham on Span Board and exceeded in subjective memory reports at follow-up as assessed by the Cognitive Failures Questionnaire (CFQ). The Cogmed group demonstrated better performance on the Functional Activities Questionnaire (FAQ), a measure of adjustment and far transfer, at follow-up. Both groups, especially Cogmed, enjoyed the intervention.

CONCLUSIONS

Results suggest that WM was enhanced in both groups of older adults with MCI. Cogmed was better on one core WM measure and had higher ratings of satisfaction. The Sham condition declined on adjustment.

Memory intervention: the value of a clinical holistic program for older adults with memory impairments

OBJECTIVES

Increasingly, cognitive training appears an asset in improving attention and working memory for older adults. We conducted a study involving a 'holistic' training program for several cohorts of older adults (N = 112), targeting community residents with a spectrum of memory complaints ranging from Age Associated Memory Impairment to mild dementia.

METHOD

We developed a 7-session, manualized program targeting concentration, as well as mindfulness, exercise, stress reduction, socialization, diet, and values/identity techniques. We applied this model to 11 cohorts and conducted pre- and post-testing on memory (List Learning, Story Memory, Coding, Digit Span, Recall, and Recognition) and function (Functional Assessment Questionnaire). We also divided the Memory Group by Risk Status - Low, Medium, and High.

RESULTS

Results showed that the Memory Clinic Group as a whole improved on this training on most scales. When broken down by risk status, the Low and Medium Risk Groups were statistically superior to the High Risk Group on cognitive measures.

CONCLUSION

There were differences also on adjustment, this time favoring only the Low Risk Groups. Holistic memory training seems to be impactful for older adults.

Influence of Alzheimer disease family history and genetic risk on cognitive performance in healthy middle-aged and older people

OBJECTIVES

Identification of risk factors for Alzheimer disease (AD) is critical for establishing effective diagnostic and therapeutic strategies. Carrying the ε4 allele of the apolipoprotein E gene (APOE4) and having a family history of the disease are two such factors, with family history risk reflecting additional yet unknown or rarely studied genetic and perhaps nongenetic risks. Our aim was to determine the influence of APOE genotype and family history status on cognitive performance in healthy individuals.

DESIGN

Longitudinal study.

SETTING

Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles.

PARTICIPANTS

Seventy-two cognitively healthy middle-aged and older people (mean age ± SD: 62 ± 9 years).

MEASUREMENTS

Neuropsychological examinations at baseline and after 2 years.

RESULTS

Subjects with a family history of AD had lower baseline scores in processing speed, executive functioning, memory encoding, and delayed memory when compared with those without a family history. The family history risk factor did not influence degree of cognitive decline over time. By contrast, baseline cognitive performance did not vary according to APOE4 carrier status. Non-APOE4 carriers showed improved cognitive performance in the memory domains at follow-up, while performance of APOE4 carriers did not change.

CONCLUSIONS

Our data highlight the unique contributions of each risk factor to cognitive performance in healthy people. Both factors should be modeled in neuropsychological assessments of people at risk for AD.

Increasing depressive symptoms in children of Alzheimer parents

Children of persons with Alzheimer disease (AD) are at increased risk of developing AD themselves, but specific factors that predict AD in this population have yet to be elucidated. Various studies indicate depressive symptoms may predate clinical AD and represent a risk factor and/or prodrome of incipient dementia, but their relevance for AD offspring remains uncertain. As part of a longitudinal family study of AD, we assessed depressive symptomatology in 30 middle aged AD offspring (mean age at baseline: 41.2). Their mean total scores on the Hamilton Depression Rating scale increased from 1.8 to 5.3 (P < .001) across a 20-year interval. Neurocognitive performance remained stable in a subset of this cohort (N = 25) over the same interval. Findings from this small convenience sample suggest emerging depressive symptoms may be among the earliest signs of subsequent dementia in this high-risk population but require confirmation through further longitudinal follow-up and replication in larger populations.

Cognitive profiles of aging and aging-related conditions

This review presents some of the current research and thinking regarding the neuropsychological features associated with aging and aging-related conditions. In the context of the current longevity revolution, many older adults are increasingly concerned about their cognitive performance and the risk for cognitive decline. This makes it critically important to understand the neuropsychological profiles of normal aging and the cognitive features of conditions associated with aging, such as age-associated memory impairment, mild cognitive impairment and dementia. There are also several factors that can modify the neuropsychological abilities and outcomes associated with aging, including gender, genetic status, lifestyle issues and education. The authors point to the importance for future research to embrace a fluid or multifactorial approach to neuropsychology, to focus on those factors contributing to healthy cognition and successful aging, and to correlate neuropsychological changes with the results of neuroimaging.