title: Bilingualism as a Contributor to Cognitive Reserve? Evidence from Cerebral Glucose Metabolism in Mild Cognitive Impairment and Alzheimer's Disease.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Section for Geriatric Psychiatry, University Clinic Heidelberg , Heidelberg , Germany.
authors.forename: Magdalena Eva
authors.initials: ME
authors.lastname: Kowoll
authors.affiliation: Section for Geriatric Psychiatry, University Clinic Heidelberg , Heidelberg , Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Degen
authors.affiliation: Section for Geriatric Psychiatry, University Clinic Heidelberg , Heidelberg , Germany.
authors.forename: Lina
authors.initials: L
authors.lastname: Gorenc
authors.affiliation: Department of Psychiatry and Psychotherapy, University Hospital Leipzig , Leipzig , Germany.
authors.forename: Anika
authors.initials: A
authors.lastname: Küntzelmann
authors.affiliation: Section for Geriatric Psychiatry, University Clinic Heidelberg , Heidelberg , Germany.
authors.forename: Iven
authors.initials: I
authors.lastname: Fellhauer
authors.affiliation: Department of Nuclear Medicine, University Clinic , Heidelberg , Germany.
authors.forename: Frederik
authors.initials: F
authors.lastname: Giesel
authors.affiliation: Department of Nuclear Medicine, University Clinic , Heidelberg , Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Haberkorn
authors.affiliation: Section for Geriatric Psychiatry, University Clinic Heidelberg , Heidelberg , Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Schröder
keywords: Alzheimer’s disease; FDG-PET; bilingualism; cognitive reserve; mild cognitive impairment