title: Changes in auditory feedback connections determine the severity of speech processing deficits after stroke.
abstract: We compared brain structure and function in two subgroups of 21 stroke patients with either moderate or severe chronic speech comprehension impairment. Both groups had damage to the supratemporal plane; however, the severe group suffered greater damage to two unimodal auditory areas: primary auditory cortex and the planum temporale. The effects of this damage were investigated using fMRI while patients listened to speech and speech-like sounds. Pronounced changes in connectivity were found in both groups in undamaged parts of the auditory hierarchy. Compared to controls, moderate patients had significantly stronger feedback connections from planum temporale to primary auditory cortex bilaterally, while in severe patients this connection was significantly weaker in the undamaged right hemisphere. This suggests that predictive feedback mechanisms compensate in moderately affected patients but not in severely affected patients. The key pathomechanism in humans with persistent speech comprehension impairments may be impaired feedback connectivity to unimodal auditory areas.
authors.affiliation: Wellcome Trust Centre for Neuroimaging, University College London, London, UK.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Schofield
authors.forename: Will D
authors.initials: WD
authors.lastname: Penny
authors.forename: Klaas E
authors.initials: KE
authors.lastname: Stephan
authors.forename: Jennifer T
authors.initials: JT
authors.lastname: Crinion
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Thompson
authors.forename: Cathy J
authors.initials: CJ
authors.lastname: Price
authors.forename: Alexander P
authors.initials: AP
authors.lastname: Leff
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001303:Auditory Cortex / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology; D001306:Auditory Pathways / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology; D001931:Brain Mapping; D032882:Comprehension; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D017711:Nonlinear Dynamics; D010100:Oxygen / Q000097:blood; D013064:Speech Disorders / Q000209:etiology* / Q000473:pathology*; D013067:Speech Perception / Q000502:physiology*; D020521:Stroke / Q000150:complications*
chemical_list: D010100:Oxygen