Bilingualism protects anterior temporal lobe integrity in aging.
Cerebral gray-matter volume (GMV) decreases in normal aging but the extent of the decrease may be experience-dependent. Bilingualism may be one protective factor and in this article we examine its potential protective effect on GMV in a region that shows strong age-related decreases-the left anterior temporal pole. This region is held to function as a conceptual hub and might be expected to be a target of plastic changes in bilingual speakers because of the requirement for these speakers to store and differentiate lexical concepts in 2 languages to guide speech production and comprehension processes. In a whole brain comparison of bilingual speakers (n = 23) and monolingual speakers (n = 23), regressing out confounding factors, we find more extensive age-related decreases in GMV in the monolingual brain and significantly increased GMV in left temporal pole for bilingual speakers. Consistent with a specific neuroprotective effect of bilingualism, region of interest analyses showed a significant positive correlation between naming performance in the second language and GMV in this region. The effect appears to be bilateral though because there was a nonsignificantly different effect of naming performance on GMV in the right temporal pole. Our data emphasize the vulnerability of the temporal pole to normal aging and the value of bilingualism as both a general and specific protective factor to GMV decreases in healthy aging.
Department of Speech and Hearing Sciences, University of Hong Kong, Hong Kong, China; Centre of Cognitive Neurosciences, Department of Clinical Neurosciences, San Raffaele Scientific Institute, San Raffaele University, Milano, Italy. Electronic address: abutalebi.jubin@hsr.it.
Jubin
J
Abutalebi
Centre of Cognitive Neurosciences, Department of Clinical Neurosciences, San Raffaele Scientific Institute, San Raffaele University, Milano, Italy; Institute of Molecular Bioimaging and Physiology, National Research Council (IBFM-CNR), Milan, Italy.
Matteo
M
Canini
Institute of Molecular Bioimaging and Physiology, National Research Council (IBFM-CNR), Milan, Italy.
Pasquale A
PA
Della Rosa
Department of Speech and Hearing Sciences, University of Hong Kong, Hong Kong, China.
Lo Ping
LP
Sheung
Department of Cognitive, Perceptual and Brain Sciences, University College London, London, UK.
David W
DW
Green
Department of Speech and Hearing Sciences, University of Hong Kong, Hong Kong, China.
Brendan S
BS
Weekes
D000368:Aged; D000375:Aging / Q000473:pathology* / Q000502:physiology*; D005260:Female; D066128:Gray Matter / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019303:Multilingualism; D065840:Protective Factors; D013702:Temporal Lobe / Q000473:pathology*
Aging; Bilingualism; Language proficiency; Temporal pole (TP); Voxel based morphometry (VBM)