Background: Swallowing dysfunction is common and disabling after acute stroke; however, the mechanism of dysphagia or recovery of swallowing from dysphagia remains uncertain. The purpose of this study was to explore cerebral activation of swallowing in dysphagia using functional MRI (fMRI) to compare the functional anatomy of swallowing in unilateral hemispheric stroke patients and healthy adults.
Methods: In total, five left hemispheric stroke patients with dysphagia, five right hemispheric stroke patients with dysphagia and 10 healthy controls were examined with event related fMRI while laryngeal swallow related movements were recorded. Data were processed using the general linear model.
Results: A multifocal cerebral representation of swallowing was identified predominantly in the left hemisphere, in a bilateral and asymmetrical manner. Cerebral activation during swallowing tasks was localised to the precentral, postcentral and anterior cingulate gyri, insula and thalamus in all groups. Activation of volitional swallowing in dysphagic unilateral hemispheric stroke patients might require reorganisation of the dominant hemispheric motor cortex, or a compensatory shift in activation to unaffected areas of the hemisphere.
Conclusions: The results indicate that unilateral stroke of either cerebral hemisphere can produce dysphagia. Effective recovery is associated with cerebral activation related to cortical swallowing representation in the compensating or recruited areas of the intact hemisphere. Functional MRI is a useful method for exploring the spatial localisation of changes in neuronal activity during tasks that may be related to recovery. Therefore, the subsequent information gleaned from changes in neural plasticity could be useful for assessing the prognosis of dysphagic stroke.
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Funding This research was supported by the National Natural Science Foundation of China (grant Nos 30625024, 30728017, 30525030 and 60736029), Key research project of science and technology of MOE (107097), National Basic Research Programme of China (973 Programme No 2007CB512305), National High Technology Programme of China (863 Programme No 2008AA02Z408 and 2007AA02Z482), the Programme of State Administration of Traditional Chinese Medicine of Zhejiang Province (No 2006Y016), the Construction Project of Medical Key Subject in Zhejiang Province of China (Rehabilitation Medicine, 2007.7–2010.7).
Competing interests None.
Ethics approval The study protocol was approved by the institutional ethics committee at Sichuan University.
Provenance and Peer review Not commissioned; externally peer reviewed.
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