Journal article
The right hemisphere supports but does not replace left hemisphere auditory function in patients with persisting aphasia
Brain (London, England : 1878), Vol.136(6), pp.1901-1912
06/01/2013
DOI: 10.1093/brain/awt087
PMCID: PMC3673464
PMID: 23715097
Abstract
In this study, we used magnetoencephalography and a mismatch paradigm to investigate speech processing in stroke patients with auditory comprehension deficits and age-matched control subjects. We probed connectivity within and between the two temporal lobes in response to phonemic (different word) and acoustic (same word) oddballs using dynamic causal modelling. We found stronger modulation of self-connections as a function of phonemic differences for control subjects versus aphasics in left primary auditory cortex and bilateral superior temporal gyrus. The patients showed stronger modulation of connections from right primary auditory cortex to right superior temporal gyrus (feed-forward) and from left primary auditory cortex to right primary auditory cortex (interhemispheric). This differential connectivity can be explained on the basis of a predictive coding theory which suggests increased prediction error and decreased sensitivity to phonemic boundaries in the aphasics' speech network in both hemispheres. Within the aphasics, we also found behavioural correlates with connection strengths: a negative correlation between phonemic perception and an inter-hemispheric connection (left superior temporal gyrus to right superior temporal gyrus), and positive correlation between semantic performance and a feedback connection (right superior temporal gyrus to right primary auditory cortex). Our results suggest that aphasics with impaired speech comprehension have less veridical speech representations in both temporal lobes, and rely more on the right hemisphere auditory regions, particularly right superior temporal gyrus, for processing speech. Despite this presumed compensatory shift in network connectivity, the patients remain significantly impaired.
Details
- Title: Subtitle
- The right hemisphere supports but does not replace left hemisphere auditory function in patients with persisting aphasia
- Creators
- Sundeep Teki - University College LondonGareth R. Barnes - Wellcome Centre for Human NeuroimagingWilliam D. Penny - Wellcome TrustPaul Iverson - University College LondonZoe V. J. Woodhead - Wellcome TrustTimothy D. Griffiths - Newcastle UniversityAlexander P. Leff - University College London
- Resource Type
- Journal article
- Publication Details
- Brain (London, England : 1878), Vol.136(6), pp.1901-1912
- Publisher
- Oxford Univ Press
- DOI
- 10.1093/brain/awt087
- PMID
- 23715097
- PMCID
- PMC3673464
- ISSN
- 0006-8950
- eISSN
- 1460-2156
- Number of pages
- 12
- Grant note
- ME033459MES / Wellcome Trust National Institute for Health Research University College London Hospitals Biomedical Research Centre James S McDonnell Foundation
- Language
- English
- Date published
- 06/01/2013
- Academic Unit
- Psychological and Brain Sciences
- Record Identifier
- 9984627247702771
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