Electrophysiological Evaluation of Pharyngeal Phase of Swallowing in Patients with Parkinson’s Disease Cumhur Ertekin, MD, 1,2 * Sultan Tarlaci, MD, 1 Ibrahim Aydogdu, MD, 1,2 Nefati Kiylioglu, MD, 1 Nur Yuceyar, MD, 1 A. Bulent Turman, MD, 3 Yaprak Secil, MD, 1 and Figen Esmeli, MD 2 1 Department of Neurology, Ege University Medical School Hospital, Bornova, Izmir, Turkey 2 Department of Clinical Neurophysiology, Ege University Medical School Hospital, Bornova, Izmir, Turkey 3 Department of Biomedical Sciences, University of Sydney, Sydney, Australia Abstract: We studied the various physiological aspects of oro- pharyngeal swallowing in Parkinson’s disease (PD). Fifty-eight patients with PD were investigated by clinical and electrophysi- ological methods that measured the oropharyngeal phase of swallowing. All patients except 1 had mild to moderate degree of disability score. Dysphagia was demonstrated in 53% of all patients in whom the test of dysphagia limit was abnormal. All PD patients with or without dysphagia displayed the following abnormalities: (1) the triggering of the swallowing reflex was prolonged probably due to inadequate bolus control in the mouth and tongue and/or a specific delay in the execution of the swallowing reflex; (2) the duration of the pharyngeal reflex time was extremely prolonged due to slowness of the sequential muscle movements, especially those of the suprahyoid- submental muscles; (3) cricopharyngeal muscle of the upper oesophageal sphincter was found to be electrophysiologically normal; and (4) the electrophysiological phenomena in PD pa- tients could not be strongly correlated with the degree of the disability and clinical score of the PD. It was concluded that various motor disorders of PD have considerable influence on oropharyngeal swallowing: hypokinesia, reduced rate of spon- taneous swallowing, and the slowness of segmented but coor- dinated sequential movements rather than any abnormalities in the central pattern generator of the bulbar center. Some com- pensatory mechanisms in the course of PD may explain the benign nature of swallowing disorder until the terminal stage of the disease. Similarly, the swallowing problems of PD are not only related with the dopamine deficiency; some other nondo- paminergic mechanisms may also be involved. © 2002 Move- ment Disorder Society Key words: Parkinson’s disease; oropharyngeal dysphagia; electromyography; cricopharyngeal muscle Three stages of deglutition, namely, oral, pharyngeal, and oesophageal phases may be affected in patients with Parkinson’s disease (PD). Different kinds of swallowing disorders have been described in PD according to the focus, attention, and interest of investigators to different stages of deglutition. Oral phase abnormalities, which have been reported by many investigators, include inefficient mastication, impaired bolus formation, hesitant deglutition, and glot- tic tremor. 1–11 Abnormalities of the oral stage of deglu- tition, characterized by difficulty in bolus formation and the delay in swallowing reflex, have been suggested as the main source of deglutition problems in PD pa- tients. 4,11 However, it has also been proposed by some investigators that dysphagia in PD cannot be restricted to the oral phase of deglutition; therefore, the abnormalities associated with the pharyngeal stage of swallowing are at least equally important. 1,2,5,7–10 These abnormalities have been detected mostly by radiological methods and, thus, do not necessarily produce the symptoms of dys- phagia unless the laryngeal closure during swallowing also becomes inadequate and some material enters the airway during or after the swallow. 12,13 Despite radio- logical aspiration, PD patients may be silent aspirators with decreased cough reflex and lack of awareness of aspiration. 8–10 Therefore, it is necessary to detect those asymptomatic PD patients who carry a potential risk for future swallowing problems. We sought such patients *Correspondence to: Dr. Cumhur Ertekin, Talatpapa Bulvari, Go ¨nc ¸ Apt., No: 12, D3, 35220 Alsancak, Izmir, Turkey. E-mail: erteker@unimedya.net.tr Received 10 December 2001; Revised 20 February 2002; Accepted 26 February 2002 Published online 25 April 2002 in Wiley InterScience (www. interscience.wiley.com). DOI 10.1002/mds.10240 Movement Disorders Vol. 17, No. 5, 2002, pp. 942–949 © 2002 Movement Disorder Society 942