Influence of Bolus Volume on HyoidMovements in Normal Individuals and Patients with Parkinson's Disease

     Axel R. Wintzen, Umesh A. Badrising, Raymund A.C. Roos, Jan Vielvoye and Lishya Liauw

Abstract:   The swallowing movements of 22 ambulant patients with Parkinson's disease were examined by videofluoroscopy, 15 spouses serving as controls. The relation between bolus volume and movement of the hyoid bone was studied in the lateral view to assess the adaptation of the pharynx musculature. Although movement characteristics of the hyoid varied considerably both intra- and interindividually, mean values followed typical patterns. In controls, the position of the hyoid before the start of the swallow tended to be lower as the bolus volume increased, apparently to create space in the oral cavity by lowering the floor of the mouth. This trend was not seen in the group of Parkinson patients. We suppose that this specific lack of adaptation represents hypokinesia. The amplitude of the hyoid movement did not change with increasing bolus volumes, either in patients or in controls. Moreover, Parkinson patients had many more aborted swallowing movements ("hesitations") than controls, probably representing defective switching from the voluntary phase of swallowing to the involuntary, automatic phase.

Can. J. Neurol. Sci. 1994; 21: 57-59