Effect of Visuospatial Neglect on Electrophysiological Parameters of Oropharyngeal Swallowing

Abstract

Objective: The aim of this study was to determine the effect of visuospatial neglect on the electrophysiological parameters of oropharyngeal swallowing. Material and Methods: Twenty-six healthy volunteers and 42 stroke patients with complaints of dysphagia were included in the study. The patients were grouped as left hemiplegic patients with visuospatial neglect, left hemiplegic patients without visuospatial neglect, and right hemiplegic patients without visuospatial neglect. Submental electromyographic activity and laryngeal vertical movements were electrophysiologically recorded while each subject swallowed water. Results: The time required for triggering the pharyngeal phase of swallowing (A-0) and the duration of the pharyngeal phase of oropharyngeal swallowing (A-C) were significantly prolonged in left hemiplegia patients with neglect compared with the patients in the other groups (p<0.05). The time necessary for the elevation, closure, and upward relocation of the larynx (0-2 interval) was prolonged, and the dysphagia limit was decreased in the left hemiplegia patients with neglect compared with the patients in the other groups. The prolongation of larynx movement and decrease in dysphagia limit in patients with neglect were significantly different to the relative measures in the healthy volunteer group (p<0.05) but not to those in the patients without neglect (p>0.05). Conclusion: Perceptual deficit is apt to play a significant role in the development of dysphagia via reduced stimulus detection and discriminative capacity in the oropharynx. Thus, we propose that stroke patients with neglect may require a swallowing evaluation, regardless of whether they have complaints of dysphagia.