White Matter Changes and Word Finding Failures with Increasing Age

Abstract

BackgroundIncreasing life expectancy necessitates the better understanding of the neurophysiological underpinnings of age-related cognitive changes. The majority of research examining structural-cognitive relationships in aging focuses on the role of age-related changes to grey matter integrity. In the current study, we examined the relationship between age-related changes in white matter and language production. More specifically, we concentrated on word-finding failures, which increase with age.Methodology/Principal FindingsWe used Diffusion tensor MRI (a technique used to image, in vivo, the diffusion of water molecules in brain tissue) to relate white matter integrity to measures of successful and unsuccessful picture naming. Diffusion tensor images were used to calculate Fractional Anisotropy (FA) images. FA is considered to be a measure of white matter organization/integrity. FA images were related to measures of successful picture naming and to word finding failures using voxel-based linear regression analyses. Successful naming rates correlated positively with white matter integrity across a broad range of regions implicated in language production. However, word finding failure rates correlated negatively with a more restricted region in the posterior aspect of superior longitudinal fasciculus.Conclusions/SignificanceThe use of DTI-MRI provides evidence for the relationship between age-related white matter changes in specific language regions and word finding failures in old age.

Dominant hemisphere functional networks compensate for structural connectivity loss to preserve phonological retrieval with aging

“…We have previously shown that increased RIFG activation is related to preserved performance in participants more prone to making errors and may play a role in counteracting competing inputs (Stamatakis et al. 2011; Geva et al. 2012).…”

“…2008; Stamatakis et al. 2011; Antonenko and Flöel 2014; Geerligs et al. 2014) and segregation of functional networks with age (Oldfield 1971; Chan et al.…”

“…Furthermore, a study and modality‐specific FA template was created (Stamatakis et al. 2011) to which all raw FA images were normalized prior to group analysis. Each participant's FA images were visually assessed to ensure successful spatial normalization to this template before group analysis.…”

“…2001; Stamatakis et al. 2011), if these left hemispheric regions indeed preserve function with increasing age, we expect their functional connectivity to be higher in older adults. Also, functional connectivity would be expected to positively correlate with behavioral performance.…”

Grammar learning in older adults is linked to white matter microstructure and functional connectivity

“…Previous studies have linked lower language performance in older adults to deterioration in bilateral white matter microstructure, as measured by fractional anisotropy (FA) using magnetic resonance imaging (MRI)-based diffusion tensor imaging (DTI; Obler et al, 2010;Stamatakis et al, 2011). For example, Obler et al (2010) found that naming performance was correlated to FA values in left-hemisphere language-relevant brain regions as well as their right-hemisphere homologues.…”