Right Hemisphere Grey Matter Volume and Language Functions in Stroke Aphasia

Abstract

The role of the right hemisphere (RH) in recovery from aphasia is incompletely understood. The present study quantified RH grey matter (GM) volume in individuals with chronic stroke-induced aphasia and cognitively healthy people using voxel-based morphometry. We compared group differences in GM volume in the entire RH and in RH regions-of-interest. Given that lesion site is a critical source of heterogeneity associated with poststroke language ability, we used voxel-based lesion symptom mapping (VLSM) to examine the relation between lesion site and language performance in the aphasic participants. Finally, using results derived from the VLSM as a covariate, we evaluated the relation between GM volume in the RH and language ability across domains, including comprehension and production processes both at the word and sentence levels and across spoken and written modalities. Between-subject comparisons showed that GM volume in the RH SMA was reduced in the aphasic group compared to the healthy controls. We also found that, for the aphasic group, increased RH volume in the MTG and the SMA was associated with better language comprehension and production scores, respectively. These data suggest that the RH may support functions previously performed by LH regions and have important implications for understanding poststroke reorganization.

Neural networks for sentence comprehension and production: An ALE‐based meta‐analysis of neuroimaging studies

“…It may be that this region is engaged only in limited circumstances, as we argued above for left inferior frontal cortical regions (including the left insula), though whether these noncanonical sentences elicit activity in this region because of difficult prosody (as has been suggested for right inferior frontal cortex; Friederici, 2011) or for other reasons remains to be determined. As a second point, the engagement of this region in the comprehension of complex sentences in healthy individuals is consistent with the hypothesis that this region (and nearby and/or functionally connected regions) might be capable of contributing to the recovery of comprehension of complex sentences in individuals with agrammatic aphasia, though precisely how and to what extent is still an active area of investigation (Gainotti, 2015;Lukic et al, 2017).…”

Motor and cognitive impairments in spinocerebellar ataxia type 7 and its correlations with cortical volumes

“…Supporting this possibility, changes in lateralization as a compensatory mechanism has been described in Alzheimer Disease (Fallgatter et al., ), Mild Cognitive Impairment (Yeung et al., ) and Schizophrenia (Sommer, Ramsey, & Kahn, ; Weiss et al., ); whereas the increased of right hemisphere GMV in classical left‐lateralized language areas has been associated with better language comprehension in aphasic patients (Lukic et al., ). However, compensatory reorganization of cognitive functions in SCA7 should be explored further, since other mechanisms as increased functional connectivity has been suggested (Hernandez‐Castillo et al., ).…”

Multivariate Approaches to Understanding Aphasia and its Neural Substrates

“…Considering the clear-cut multidimensionality of aphasia and its neural underpinnings, it is no surprise that multidimensional approaches have been growing in prevalence and prominence over the last few years. Disentangling multiple behavioral and neural variables requires large datasets, so it is encouraging that the field of language neuroscience is becoming increasingly collaborative, with the emergence of a number of large scale projects that will generate datasets of the size and substance that will form a sound basis for future progress [32,[93][94][95].…”