. Journal of Speech-Language-Hearing Research [Internet]. 2020.
Brain imaging has provided puzzle pieces in the understanding of language. In neurologically
healthy populations, the structure of certain brain regions is associated with particular
language functions (e.g., semantics, phonology). In studies on focal brain damage,
certain brain regions or connections are considered sufficient or necessary for a
given language function. However, few of these account for the effects of lesioned
tissue on the “functional” dynamics of the brain for language processing. Here, functional
connectivity (FC) among semantic–phonological regions of interest (ROIs) is assessed
to fill a gap in our understanding about the neural substrates of impaired language
and whether connectivity strength can predict language performance on a clinical tool
in individuals with aphasia.
Clinical assessment of language, using the Western Aphasia Battery–Revised, and resting-state
functional magnetic resonance imaging data were obtained for 30 individuals with chronic
aphasia secondary to left-hemisphere stroke and 18 age-matched healthy controls. FC
between bilateral ROIs was contrasted by group and used to predict Western Aphasia
Network coherence was observed in healthy controls and participants with stroke. The
left–right premotor cortex connection was stronger in healthy controls, as reported
by New et al. (2015) in the same data set. FC of (a) connections between temporal
regions, in the left hemisphere and bilaterally, predicted lexical–semantic processing
for auditory comprehension and (b) ipsilateral connections between temporal and frontal
regions in both hemispheres predicted access to semantic–phonological representations
and processing for verbal production.
Network connectivity of brain regions associated with semantic–phonological processing
is predictive of language performance in poststroke aphasia. The most predictive connections
involved right-hemisphere ROIs—particularly those for which structural adaptions are
known to associate with recovered word retrieval performance. Predictions may be made,
based on these findings, about which connections have potential as targets for neuroplastic
functional changes with intervention in aphasia.
Supplemental Material https://doi.org/10.23641/asha.12735785