Neuroanatomical Predictors of Dysphagia after Stroke: Voxel-Based Lesion Symptom Mapping Study

Abstract

Objective: Dysphagia is a common consequence of stroke with a negative effect on the clinical outcome. Given thesepotential outcomes, it is important to identify the precursors to dysphagia after stroke. The aims of this study wereto identify lesions associated with dysphagia after an ischemic supratentorial stroke using voxel-based lesion symptom mapping (VLSM) and compare the difference in the lesion pattern between the oral and pharyngeal phasedysphagia. Methods: Stroke patients who met the following inclusion criteria were screened retrospectively between January2012 and November 2014: a first-ever stroke, supratentorial lesion and who underwent brain MRI and functionaldysphagia scale (FDS) from videofluoroscopic swallowing study (VFSS). Finally, the MRI data of 83 patients wereanalyzed. Statistical maps of the lesion contribution related to dysphagia were generated using VLSM. Results: VLSM showed that FDS was associated with damage to the putamen, caudate, insula, frontal precentral gyrus, and inferior frontal gyrus. The lesions were distributed more widely in the left than right hemisphere. Lesionscorrelated with the FDS oral score were distributed mainly in the frontal lobe and insula. Otherwise, the associatedlesion with the FDS pharyngeal score was mainly the basal ganglia. Conclusion: In these results, lesions that correlated with dysphagia were distributed more widely in the left hemisphere, reflecting the possibility of lateralization of the swallowing function. Oral phase dysphagia was associatedwith left frontal lobe and insula; the lesion correlated with the cognitive function or apraxia. On the other hand, VLSMrevealed the lesions associated with pharyngeal dysphagia to be the basal ganglia, which is a structure that plays arole in the automatic motor control network.