Abstract/Summary

Background: Understanding the factors that influence language recovery in aphasia is important for improving prognosis and treatment. Chronic comprehension impairments Wernicke’s-type aphasia (WA) are associated with impairments in auditory and phonological processing, compounded by semantic and executive difficulties. This study investigated whether the recovery of auditory, phonological, semantic or executive factors underpins the recovery from WA comprehension impairments by charting changes in the neuropsychological profiles from the sub-acute to the chronic phase. Method: This study used a prospective, longitudinal, observational design. Twelve WA participants with superior temporal lobe lesions were recruited before 2 months post stroke onset (MPO). Language comprehension was measured alongside a neuropsychological profile of auditory, phonological and semantic processing alongside phonological short-term memory and nonverbal reasoning at three post stroke time points: 2.5, 5 and 9MPO. Results: Language comprehension displayed a strong and consistent recovery between 2.5 and 9MPO. Improvements were also seen for slow auditory temporal processing, phonological short-term memory, and semantic processing, but not for rapid auditory temporal, spectrotemporal and phonological processing. Despite their lack of improvement, rapid auditory temporal processing at 2.5MPO and phonological processing at 5MPO predicated comprehension outcomes at 9MPO. Conclusions: These results indicate that recovery of language comprehension in WA can be predicted from fixed auditory processing in the subacute stage. This suggests that speech comprehension recovery in WA results from reorganisation of the remaining language comprehension network to enable the residual speech signal to be processed more efficiently, rather than partial recovery of underlying auditory, phonological or semantic processing abilities.