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

Pyun, Sung Bom; Yoo, Hyun Joon; Jung, Youjin; Tae, Woo Suk

Abstract

OBJECTIVE
Dysphagia is a common consequence of stroke with a negative effect on the clinical outcome. Given these potential outcomes, it is important to identify the precursors to dysphagia after stroke. The aims of this study were to 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 phase dysphagia.
METHODS
Stroke patients who met the following inclusion criteria were screened retrospectively between January 2012 and November 2014: a first-ever stroke, supratentorial lesion and who underwent brain MRI and functional dysphagia scale (FDS) from videofluoroscopic swallowing study (VFSS). Finally, the MRI data of 83 patients were analyzed. 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. Lesions correlated with the FDS oral score were distributed mainly in the frontal lobe and insula. Otherwise, the associated lesion 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 associated with left frontal lobe and insula; the lesion correlated with the cognitive function or apraxia. On the other hand, VLSM revealed the lesions associated with pharyngeal dysphagia to be the basal ganglia, which is a structure that plays a role in the automatic motor control network.