Task-induced brain activity in aphasic stroke patients: what is driving recovery?

摘要: The estimated prevalence of aphasia in the UK and USA is 250 000 1 000, respectively. commonest aetiology stroke. impairment may improve with behavioural therapy, trials using cortical stimulation or pharmacotherapy are undergoing proof-of-principle investigation, but mixed results. Aphasia a heterogeneous syndrome, simple classifications according to Broca-Wernicke-Lichtheim model inadequately describe diverse communication difficulties which patients present. Greater knowledge how intact neural networks promote recovery after aphasic stroke, either spontaneously response interventions, will result clearer hypotheses about treatment aphasia. Twenty-five years ago, pioneering study on healthy participants heralded introduction functional neuroimaging mechanisms from Over ensuing decades, such studies have been interpreted as supporting one three hypotheses, not mutually exclusive. first two predate neuroimaging: that consequence reconstitution domain-specific language systems tissue around lesion (the ‘perilesional’ hypothesis), by homotopic cortex contralateral hemisphere ‘laterality-shift’ hypothesis). third loss transcallosal inhibition hinders ‘disinhibition’ These different at times give conflicting views rehabilitative intervention; for example, should attempt activate inhibit region techniques recovery? This review proposes although imaging data statistically valid most cases, their interpretation has often favoured explanation while ignoring plausible alternatives. In our view, this particularly evident when attributed activity ‘language networks’ occupying sites observed participants. we argue much distribution what language-specific activity, midline regions, an upregulation domain-general cognitive control attention, responding task-dependent manner increased ‘effort’ damaged downstream impaired. We further propose it inability fully these sub optimal some patients. Interpretation terms affords insights into novel approaches rehabilitation.