Bilingualism provides a neural reserve for aging populations

Abstract

It has been postulated that bilingualism may act as a cognitive reserve and recent behavioral evidence shows that bilinguals are diagnosed with dementia about 4-5 years later compared to monolinguals. In the present study, we investigated the neural basis of these putative protective effects in a group of aging bilinguals as compared a matched monolingual control group. For this purpose, participants completed the Erikson Flanker task and their performance was correlated to grey matter (GM) volume in order to investigate if cognitive performance predicts GM volume specifically in areas affected by aging. We performed an ex-Gaussian analysis on the resulting RTs and report that aging bilinguals performed better than aging monolinguals on the Flanker task.Bilingualism was overall associated with increased GM in the ACC Task performance correlated with decreased GM in the DLPFC only in monolinguals. Taken together, these neural regions might underlie the benefits of bilingualism and act as a neural reserve that protects against the cognitive decline that occurs during aging..

Data trimming procedure can eliminate bilingual cognitive advantage

“…And this was also the case when the potential effect of laboratory was eliminated. This is consistent with earlier findings that the bilingualism effect emerges partially in the tail of response distributions (Abutalebi et al, 2015;Calabria et al, 2011;Tse & Altarriba, 2012). It appears that, when these prolonged responses were trimmed or not recorded, group differences might have also been eliminated.…”

The neuroanatomy of bilingualism: how to turn a hazy view into the full picture

“…Three of them were cross-sectional studies that reported no significant brain differences (Gold et al, 2013;Grogan et al, 2012;Ressel et al, 2012). In contrast, three other studies using different techniques/measures and (Mechelli et al, 2004), cerebellum (Pliatsikas et al, 2014), left aITG (Abutalebi et al, 2014) and ACC (Abutalebi, Guidi et al, 2015). Each of the studies used different methods for the preprocessing and analysis of the data (see table 1).…”

“…This is the case for the IPL, which was initially demonstrated by Mechelli et al (2004) and then replicated by Grogan et al (2012) and but using a different methodology (namely, ROI-based rather than a whole-brain approach). And also for the ACC (Abutalebi, Guidi et al, 2015) but replication to support this finding is lacking.…”

“…On the one hand, differences appear exclusively in three regions: the left IPL (Mechelli et al, 2004), the cerebellum (Pliatsikas et al, 2014), the left aITG (Abutalebi et al, 2014) and the ACC (Abutalebi, Guidi, et al, 2015) ( Figure 1a, Table 1). However, different levels of inferences (i.e.…”

“…For example, Ressel et al (2012) In a more recent study, Abutalebi, Canini, Della Rosa, Green & Weekes (2015) extracted GM volume from ROIs in the left/right IPL using the coordinates reported by Mechelli et al (2004 Olsen et al (2015) extracted the volume of the GM for the frontal, temporal, parietal and occipital lobes for both right and left hemispheres. They investigated structural differences in the brain of 14 older bilingual adults (mean age, 70.4) who reported regular use of both English and another alphabetic language since before the age of 11.…”