title: Lifelong bilingualism and neural reserve against Alzheimer's disease: a review of findings and potential mechanisms.
abstract: Alzheimer's disease (AD) is a progressive brain disorder that initially affects medial temporal lobe circuitry and memory functions. Current drug treatments have only modest effects on the symptomatic course of the disease. In contrast, a growing body of evidence suggests that lifelong bilingualism may delay the onset of clinical AD symptoms by several years. The purpose of the present review is to summarize evidence for bilingualism as a reserve variable against AD and discuss potential underlying neurocognitive mechanisms. Evidence is reviewed suggesting that bilingualism may delay clinical AD symptoms by protecting frontostriatal and frontoparietal executive control circuitry rather than medial temporal lobe memory circuitry. Cellular and molecular mechanisms that may contribute to bilingual cognitive reserve effects are discussed, including those that may affect neuronal metabolic functions, dynamic neuronal-glial interactions, vascular factors, myelin structure and neurochemical signaling. Future studies that may test some of these potential mechanisms of bilingual CR effects are proposed.
authors.affiliation: Department of Anatomy and Neurobiology, University of Kentucky, Lexington, KY 40536, USA; Magnetic Resonance Imaging and Spectroscopy Center, University of Kentucky, Lexington, KY 40536, USA; Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536, USA. Electronic address: brian.gold@uky.edu.
authors.forename: Brian T
authors.initials: BT
authors.lastname: Gold
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000473:pathology* / Q000523:psychology; D001921:Brain / Q000473:pathology*; D058245:Cognitive Reserve; D056344:Executive Function; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory; D019303:Multilingualism; D009483:Neuropsychological Tests; D013997:Time Factors
keywords: Aging; Alzheimer's disease; Bilingualism; Cognitive reserve; Neural reserve