Bilingualism as a Contributor to Cognitive Reserve? Evidence from Cerebral Glucose Metabolism in Mild Cognitive Impairment and Alzheimer's Disease.

OBJECTIVE: Bilingualism is discussed as one factor contributing to "cognitive reserve" (CR), as it enhances executive control functions. To elucidate the underlying cerebral correlates, regional glucose uptake was compared between bilinguals and monolinguals with mild cognitive impairment (MCI) and beginning-stage Alzheimer's disease (AD) by using [(18)F]fluorodeoxyglucose (FDG) positron emission tomography (PET). METHODS: Thirty patients (73.2 ± 7.4) diagnosed with MCI or probable AD received physical and neuropsychological examinations, blood tests, and FDG-PET scans. Sixteen patients were classified as lifelong bilinguals, following the criterion of Bialystok et al., and groups were matched for age, sex, and mini mental state examination scores. Analyses were conducted using statistical parametric mapping version 8. The whole brain was used as reference region for intensity normalization and years of education were controlled for. RESULTS: Bilingual patient groups showed substantially greater impairment of glucose uptake in frontotemporal and parietal regions [including Brodmann areas (BAs) 9, 47, 40, and 21] and in the left cerebellum relative to monolingual patients. CONCLUSION: Bilingualism is likely to contribute to CR, given that bilingual patients showed more severe brain changes than monolinguals when adjusting for severity of cognitive impairment. The latter did not only comprise BAs relevant to speech and language but also structures typically involved in AD pathology, such as the temporal and the parietal cortices.

Oral health and apraxia among institutionalized elderly people--a pilot study.

OBJECTIVE: Poor oral hygiene and dental health are very common among the institutionalized elderly. The purpose of this study was to evaluate the association of apraxia with oral hygiene and/or health. MATERIALS AND METHODS: Ninety-two residents of 13 long-term care homes in southwest Germany participated in the study. For each participant, ideomotor apraxia scoring (AS) was conducted and demographic variables were collected. Participants underwent a comprehensive dental examination to assess the oral health indices gingival bleeding index (GBI), community periodontal index of treatment needs (CPITN) and denture hygiene index (DHI). Statistical comparison of dental indices among apraxic and non-apraxic individuals (cut-off < 45) was performed by use of t-tests. In addition, linear regression models were constructed with the dental indices as dependent variables. Each model was fitted with the dichotomized variable AS (pathologic or healthy) and adjusted for age and sex. RESULTS: Mean (SD) GBI of 48.5 (25.9), CPITN of 2.9 (0.7) and DHI of 82.6 (14.6) were observed among the participants. Statistical analysis revealed AS was significantly associated with all oral health indicators (p < 0.05). Linear regression models showed apraxia is a predictor of GBI (p = 0.002) and CPITN (p = 0.027), but not of denture hygiene (p = 0.916). CONCLUSIONS: Although this pilot investigation has limitations, the results suggest the presence of apraxia should be considered when planning oral healthcare strategies. Further research with larger samples is encouraged to confirm these relationships.

Autobiographical memory: a clinical perspective.

Autobiographical memory (ABM) comprises memories of one's own past that are characterized by a sense of subjective time and autonoetic awareness. Although ABM deficits are among the primary symptoms of patients with major psychiatric conditions such as mild cognitive impairment (MCI) and Alzheimer Disease (AD) or chronic schizophrenia large clinical studies are scarce. We therefore summarize and discuss the results of our clinical studies on ABM deficits in the respective conditions. In these studies ABM was assessed by using the same instrument - i.e., the Erweitertes Autobiographisches Gedächtnis Inventar (E-AGI) - thus allowing a direct comparison between diagnostic groups. Episodic ABM, especially the richness of details was impaired already in MCI and in beginning AD. Semantic memories were spared until moderate stages, indicating a dissociation between both memory systems. A recency effect was detectable in cognitively unimpaired subjects and vanished in patients with AD. A similar pattern of deficits was found in patients with chronic schizophrenia but not in patients with major depression. These ABM deficits were not accounted for by gender, or education level and did not apply for the physiological ageing process in otherwise healthy elderly. In conclusion, ABM deficits are frequently found in AD and chronic schizophrenia and primarily involve episodic rather than semantic memories. This dissociation corresponds to the multiple trace theory which hypothesized that these memory functions refer to distinct neuronal systems. The semi-structured interview E-AGI used to discern ABM changes provided a sufficient reliability measures, moreover potential effects of a number of important confounders could be falsified so far. These findings underline the relevance of ABM-assessments in clinical practice.