Lateralized memory circuit dropout in Alzheimer's disease patients.

Altered connectivity within neuronal networks is often observed in Alzheimer's disease. However, delineating pro-cognitive compensatory changes from pathological network decline relies on characterizing network and task effects together. In this study, we interrogated the dynamics of occipito-temporo-frontal brain networks responsible for implicit and explicit memory processes using high-density EEG and dynamic causal modelling. We examined source-localized network activity from patients with Alzheimer's disease (n = 21) and healthy controls (n = 21), while they performed both visual recognition (explicit memory) and implicit priming tasks. Parametric empirical Bayes analyses identified significant reductions in temporo-frontal connectivity and in subcortical visual input in patients, specifically in the left hemisphere during the recognition task. There was also slowing in frontal left hemisphere signal transmission during the implicit priming task, with significantly more distinct dropout in connectivity during the recognition task, suggesting that these network drop-out effects are affected by task difficulty. Furthermore, during the implicit memory task, increased right frontal activity was correlated with improved task performance in patients only, suggesting that right-hemisphere compensatory mechanisms may be employed to mitigate left-lateralized network dropout in Alzheimer's disease. Taken together, these findings suggest that Alzheimer's disease is associated with lateralized memory circuit dropout and potential compensation from the right hemisphere, at least for simpler memory tasks.

Adequacy of medical treatment among older persons with schizophrenia.

OBJECTIVE: This study used Krause's model of illness behavior in later life to examine factors associated with adequacy of medical treatment in a racially diverse sample of older patients (age 55 and over) with schizophrenia. METHODS: In a cross-sectional community study, 119 persons were identified from a sample of 198 persons with schizophrenia age 55 or older who developed the disorder before age 45; for comparison, 57 persons were identified from a group of 113 without the disorder. The groups were compared for treatment of one or more of four common medical disorders. Thirteen independent variables were inserted into Krause's model for the comparisons. A dependent variable was created to indicate whether persons received medication treatment for all of their medical disorders (high-treatment group). RESULTS: Significant differences were found between the schizophrenia and control groups in the proportion receiving treatment for the four physical conditions (.61 versus .83, respectively, p=.004). By logistic regression, four of 13 variables for the schizophrenia group were significantly associated (p<.01) with being in the high-treatment group: absence of depression, lower frequency of medical visits, fewer positive symptoms, and more negative symptoms. CONCLUSIONS: Although older patients with schizophrenia and their age peers had similar levels of physical disorders and rates of health visits, the former received less adequate treatment. More aggressive management of comorbid depression and positive symptoms of schizophrenia may help in improving the health of this population.

Focus on geriatric psychiatry: schizophrenia in later life: clinical symptoms and social well-being.

The number of persons aged 55 and older with a diagnosis of schizophrenia is projected to double over the next 20 years. A tripartite classification system of early-onset schizophrenia, late-onset schizophrenia, and very-late-onset schizophrenia-like psychosis has been proposed. This column reviews recent findings on the outcome and associated features of clinical symptom and social well-being categories for older adults with early-onset schizophrenia.

Depression in older adults with schizophrenia spectrum disorders: prevalence and associated factors.

RATIONALE: Although depression is common in older adults with schizophrenia, it has not been well studied. The authors examine those factors that are related to depression in a multiracial urban sample of older persons with schizophrenia. METHODS: The schizophrenia group consisted of 198 persons aged 55 or older who lived in the community and developed schizophrenia before age 45. Persons with substantial cognitive impairment were excluded from the study. A community comparison group (N = 113) was recruited using randomly selected census tract data. The authors adapted George's Social Antecedent Model of Depression, which consists of six categories comprising 16 independent variables, and used a dichotomous dependent variable based on a Center for Epidemiologic Studies Depression Scale cutoff score of > or = 16. RESULTS: The schizophrenia group had significantly more persons with clinical depression than the community comparison group (32% versus 11%, respectively; chi(2) = 28.23, df = 1, p = 0.001). Bivariate analysis revealed that eight of the 16 variables were significantly related to clinical depression in the schizophrenia group. In logistic regression, six variables retained significance: physical illness (odds ratio [OR] = 1.60, 95% confidence interval [CI], 1.17-2.18), quality of life (OR = 0.84, 95% CI, 0.76-0.93), presence of positive symptoms (OR = 1.12, 95% CI, 1.02-1.21), proportion of confidants (OR = 0.03, 95% CI, 0.01-0.39), copes by using medications (OR = 2.12, 95% CI, 1.08-4.13), and copes with conflicts by keeping calm (OR = 1.34, 95% CI, 1.03-1.74). CONCLUSION: Consistent with earlier studies of schizophrenia in older persons, the authors found physical health, positive symptoms, and several nonclinical variables to be associated with depression. Potential points for intervention include strengthening social supports, improving physical well-being, more aggressive treatment of positive symptoms, and increasing the recognition and treatment of depression.

Factors affecting quality of life in a multiracial sample of older persons with schizophrenia.

OBJECTIVE: There have been few studies of quality of life (QOL) among older persons with schizophrenia. The authors used an adaptation of Lehman's QOL model to examine factors that impact QOL in a multiracial urban sample of older persons with schizophrenia. METHODS: The schizophrenia group consisted of 198 community-dwelling persons aged 55 years and older who developed schizophrenia before age 45 years. A community comparison group (N = 113) was recruited using randomly selected block-groups. The QOL model consisted of four variable sets (demographic, objective, clinical, and subjective) comprising 19 independent variables. The dependent variable was the Quality of Life Index (QLI). RESULTS: The schizophrenia group had a significantly lower QLI score than the comparison group (21.7 versus 24.2; t = -5.36, df = 362, p = 0.001). Within the schizophrenia group, in bivariate analyses, 11 of 19 variables were significantly related to QLI. In regression analysis, six variables were significantly associated with the QLI: fewer depressive symptoms, more cognitive deficits, fewer acute life stressors, fewer medication side effects, lower financial strain, and better self-rated health. The model explained 55% of the variance in QLI, with the demographic, objective, psychiatric illness, and subjective variable sets accounting for 6%, 35%, 9%, and 5% of the variance, respectively. With the exception of the demographic set, each of the variable sets added significant variance. CONCLUSION: Our data confirmed earlier reports that older persons with schizophrenia have lower self-reported quality of life than their age-matched peers. Our findings suggest that the factors impacting on QOL are potentially ameliorable and therefore provide an opportunity to enhance the well-being of this population.