Carol Hudon

Sleep quality and 1-year incident cognitive impairment in community-dwelling older adults.

STUDY OBJECTIVES To examine in cognitively intact older men and women the associations between subjective sleep quality and 1-yr incident cognitive impairment. DESIGN Prospective cohort study. SETTING General community. PARTICIPANTS 1,664 cognitively intact individuals age 65 to 96 years. MEASUREMENTS AND RESULTS Sleep quality at baseline was measured using the Pittsburgh Sleep Quality Index (PSQI). Cognitive functioning was assessed at baseline and 12 months later using the Mini-Mental State Examination (MMSE). Incident general cognitive impairment was defined according to a follow-up MMSE score below the 15(th) percentile according to normative data and of at least 2 points below baseline. General cognitive impairments were also separated into amnestic and nonamnestic subtypes according to MMSE delayed recall performance. Associations between sleep quality indicators at baseline and incident cognitive impairment were assessed by odds ratio (OR) adjusted for age, education, baseline MMSE score, psychotropic drug use, anxiety, depressive episodes, cardiovascular conditions, and chronic diseases. Results revealed that global PSQI score was significantly linked with incident cognitive impairment (OR 1.17, 95% confidence interval (CI) 1.05-1.30) in men, but not in women. In women, sleep disturbance score (OR 2.62, 95% CI 1.41-4.86) and long sleep duration (≥ 9 hr; OR 3.70, 95% CI 1.49-9.17) were associated with nonamnestic and amnestic incident cognitive impairment, respectively. In men, short sleep duration (≤ 5 hr; OR 4.95, 95% CI 1.72-14.27) and habitual sleep efficiency score (OR 1.94, 95% CI 1.42-2.66) were associated with amnestic and general incident cognitive impairment, respectively. CONCLUSIONS Sleep quality in older adults should receive particular attention by clinicians because poor sleep quality can be an early sign of cognitive decline.

Sleep disturbances in older adults with mild cognitive impairment

BACKGROUND Normal aging and dementia are characterized by increased prevalence of sleep disorders and alterations of both sleep continuity and architecture. However, little is still known about the nature of sleep in mild cognitive impairment (MCI), which is presumably situated on the continuum from healthy aging to dementia. This unsystematic review summarizes the current literature on the prevalence and severity of sleep disturbances in MCI. METHODS Eighteen studies addressing sleep/night-time disturbances among other neuropsychiatric symptoms in individuals with MCI were identified through a search of databases and an examination of reference lists of selected papers. Fifteen of those studies reported data on prevalence or severity of sleep/night-time disturbances. RESULTS Results indicated that 14-59% of patients with MCI had sleep disturbances. These disturbances were often identified as one of the four most prevalent neuropsychiatric symptoms of MCI and were considered as clinically significant in some studies. In addition, there was some evidence that the prevalence of sleep disturbances in MCI is intermediate between that of normal aging and dementia. Longitudinal data suggest that sleep problems are associated with both incident MCI and dementia. CONCLUSIONS These findings support the hypothesis that sleep disturbances are one of the core non-cognitive symptoms of MCI. It remains to be known whether sleep problems could help to identify those individuals with MCI who will eventually develop dementia. Studies characterizing sleep more systematically are needed to verify this proposition and to clarify the associations between sleep disturbances and other neuropsychiatric symptoms of MCI.

The assessment of recognition memory using the Remember/Know procedure in amnestic mild cognitive impairment and probable Alzheimer's disease

This study used the Remember/Know (R/K) procedure combined with signal detection analyses to assess recognition memory in 20 elders with amnestic mild cognitive impairment (aMCI), 10 patients with probable Alzheimers disease (AD) as well as matched healthy older adults. Signal detection analyses first indicated that aMCI and control participants were comparable on general recognition performance. As regards AD patients, they were impaired relative to both aMCI and healthy elders. When assessing Remember and Know responses the aMCI group showed diminished sensitivity for Remember responses but intact Know responses compared to healthy elders. In contrast, AD patients showed decreased sensitivity for both Remember and Know responses compared to control and aMCI participants. The response bias index revealed that AD patients were more liberal than aMCI and control participants when providing Know responses. On the other measures, response bias was comparable between the groups. Overall, this study indicates that the R/K procedure can characterize different aspects of recognition memory performance in persons with aMCI or AD.

The Impact of DSM-IV Symptom and Clinical Significance Criteria on the Prevalence Estimates of Subthreshold and Threshold Anxiety in the Older Adult Population

OBJECTIVES Subthreshold anxiety refers to a condition where individuals do not meet the full symptom criteria (i.e., the number of symptoms required for a formal diagnosis is not reached) and/or do not report significant impairment or distress in functioning (i.e., the clinical significance criterion is not met). The purpose of this study was to examine how the symptom and the clinical significance criteria may affect the prevalence estimates of anxiety problems in the older adult population and whether applying these criteria results in an identifiable older group showing more severe anxiety. SETTING AND PARTICIPANTS Data came from a large representative sample of community-dwelling older adults age 65 years and older (N = 2,784). RESULTS Results showed that the 12-month prevalence rate of any anxiety problem varied from 5.6% when DSM-IV criteria for anxiety disorders were used to 26.2% when all subthreshold manifestations of anxiety were considered. Findings also indicated that when compared with respondents without anxiety, older adults presenting different manifestations of subthreshold or threshold anxiety appear to be more similar than different in their health and health behavior characteristics. CONCLUSIONS Subthreshold anxiety has a high prevalence and may cause significant impairment. Both symptom and clinical significance criteria do not perfectly discriminate between older adults with or without a severe anxiety problem presenting comorbid disorders and needing psychiatric help.

Memory for gist and detail information in Alzheimer's disease and mild cognitive impairment

Two experiments examined different forms of gist and detail memory in people with Alzheimers disease (AD) and those with amnestic mild cognitive impairment (MCI). In Experiment 1, 14 AD, 14 MCI, and 22 control participants were assessed with the Deese-Roediger-McDermott paradigm. Results indicated that false recognition of nonstudied critical lures (gist memory) was diminished in the AD compared with the MCI and control groups; the two latter cohorts performed similarly. In Experiment 2, 14 AD, 20 MCI, and 26 control participants were tested on a text memory task. Results revealed that recall of both macropropositions (gist information) and micropropositions (detail information) decreased significantly in AD and in MCI as compared with control participants. This experiment also revealed that the impairment was comparable between gist and detail memory. In summary, the results were consistent across experiments in the AD but not in the MCI participants. The discrepancy in MCI participants might be explained by differences in the degree of sensitivity of the experimental procedures and/or by the differences in the cognitive processes these procedures assessed.

Efficacy of a cognitive training programme for mild cognitive impairment: Results of a randomised controlled study

This study aimed to determine the efficacy of cognitive training in a 10-week randomised controlled study involving 22 individuals presenting with mild cognitive impairment of the amnestic type (MCI-A). Participants in the experimental group (n = 11) learned face–name associations using a paradigm combining errorless (EL) learning and spaced retrieval (SR) whereas participants in the control group (n = 11) were trained using an errorful (EF) learning paradigm. Psycho-educational sessions on memory were also provided to all participants. After neuropsychological screening and baseline evaluations, the cognitive training took place in 6 sessions over a 3-week period. The post-training and follow-up evaluations, at one and four weeks respectively, were performed by research assistants blind to the participants study group. The results showed that regardless of the training condition, all participants improved their capacity to learn face–name associations. A significant amelioration was also observed in participant satisfaction regarding their memory functioning and in the frequency with which the participants used strategies to support memory functions in daily life. The absence of difference between groups on all variables might be partly explained by the high variability of scores within the experimental group. Other studies are needed in order to verify the efficacy of EL learning and SR over EF in MCI-A.

Anxiety, Depression, and 1-Year Incident Cognitive Impairment in Community-Dwelling Older Adults

OBJECTIVES: To examine in men and women the independent associations between anxiety and depression and 1‐year incident cognitive impairment and to examine the association of cognitive impairment, no dementia (CIND) and incident cognitive impairment with 1‐year incident anxiety or depression.

The association between depressive and cognitive symptoms in amnestic mild cognitive impairment.

BACKGROUND Depressive symptoms are frequently observed in older adults with mild cognitive impairment (MCI). However, little is known regarding the cognitive characteristics of this important subgroup. METHODS We examined executive functions (controlled inhibition) and verbal episodic memory in 33 healthy older adults (control group), 18 older adults with amnestic MCI plus subclinical depressive symptoms (a-MCI/D+ group), and 26 older adults with amnestic MCI but no depressive symptoms (a-MCI group). RESULTS Compared to the a-MCI and control groups, patients with a-MCI/D+ showed poor controlled inhibition. Moreover, in verbal episodic memory these patients recalled fewer words than control participants on immediate free, delayed free, and delayed total (free plus cued) recall. Performance on immediate recall suggested a self-retrieval deficit, but delayed performance also revealed the existence of an encoding impairment. In the a-MCI group, participants exhibited normal performance on the executive task, but pervasive memory impairment; the memory deficit concerned free and total recall on both immediate and delayed tasks, suggesting the existence of encoding and self-retrieval disturbances. CONCLUSIONS This study reveals differences between the pattern of cognitive impairment for a-MCI/D+ and a-MCI subgroups particularly at the level of executive capacities. In terms of memory functioning, the differences between the subgroups were more subtle; more studies are needed in order to better characterize the memory impairment of a-MCI/D+ and a-MCI patients.

Potential benefits of mindfulness-based interventions in mild cognitive impairment and Alzheimer's disease: an interdisciplinary perspective.

The present article is based on the premise that the risk of developing Alzheimers disease (AD) from its prodromal phase (mild cognitive impairment; MCI) is higher when adverse factors (e.g., stress, depression, and metabolic syndrome) are present and accumulate. Such factors augment the likelihood of hippocampal damage central in MCI/AD aetiology, as well as compensatory mechanisms failure triggering a switch toward neurodegeneration. Because of the devastating consequences of AD, there is a need for early interventions that can delay, perhaps prevent, the transition from MCI to AD. We hypothesize that mindfulness-based interventions (MBI) show promise with regard to this goal. The present review discusses the associations between modifiable adverse factors and MCI/AD decline, MBIs impacts on adverse factors, and the mechanisms that could underlie the benefits of MBI. A schematic model is proposed to illustrate the course of neurodegeneration specific to MCI/AD, as well as the possible preventive mechanisms of MBI. Whereas regulation of glucocorticosteroids, inflammation, and serotonin could mediate MBIs effects on stress and depression, resolution of the metabolic syndrome might happen through a reduction of inflammation and white matter hyperintensities, and normalization of insulin and oxidation. The literature reviewed in this paper suggests that the main reach of MBI over MCI/AD development involves the management of stress, depressive symptoms, and inflammation. Future research must focus on achieving deeper understanding of MBIs mechanisms of action in the context of MCI and AD. This necessitates bridging the gap between neuroscientific subfields and a cross-domain integration between basic and clinical knowledge.

Detecting Early Preclinical Alzheimer's Disease via Cognition, Neuropsychiatry, and Neuroimaging: Qualitative Review and Recommendations for Testing

In this paper, we review studies that have investigated whether neuropsychological, neuropsychiatric, and neuroimaging measures predict decline to Alzheimers disease (AD). Prospective neuropsychological studies indicate that cognitive performance may be an excellent indicator of future progression from mild cognitive impairment (MCI) to AD, particularly when episodic memory is combined with tasks relying on executive control and language tasks. Research on neuropsychiatric symptoms reveal that depression, apathy, anxiety, and sleep disturbances can contribute to predictive models, though their sensitivity is typically lower than that found with cognitive measures. Finally, different structural brain imaging markers reveal excellent predictive accuracy. The paper discusses issues that will have to be addressed in future studies. First, it will be necessary to increase the evaluation of combined markers, as this may considerably improve predictive accuracy. Second, it will be necessary to move to earlier stages than MCI in order to expand the detection window. Third, processes of compensation and plasticity will have to be better investigated as research moves into earlier stages. The Consortium for the early identification of AD-Quebec (CIMA-Q) is presented as an instance of this approach, and potential batteries of measures are proposed.