Nerve Conduction Study for Patients with Parkinson Disease Who Developed Persistent Sensory Symptom during Optimal Levodopa Treatment

ABSTRACT

OBJECTIVE: Sensory symptoms are common in patients with Parkinson disease (PD), although its exact prevalence and causes are not well known. We aimed to investigate whether peripheral pathology contribute to chronic sensory symptoms in patients with PD by nerve conduction test. METHODS: We recruited consecutively 34 patients with clinically probable PD (Hoehn-Yahr stage, 1–3) who developed persistent sensory symptoms in their lower extremities during optimal dopamine replacement therapy. Twenty-five patients who are above age of 70 or have other possible causes of neuropathy as determined by laboratory testing or medical record were excluded. Age- and gender-matched PD patients with same disease severity who have never developed sensory symptom during the same period were allocated to paired controls. Total 18 subjects participated in this study. Nerve conduction tests on peroneal motor nerve and sural sensory nerve were performed in all subjects. Amplitude and conduction velocity were compared between the paired subjects using Wilcoxon signed rank test. RESULTS: Subjective sensory symptoms of the 9 patients were variable pain (4/9), chilling (3/9), burning (1/9), and tingling sense (1/9). There were no significant difference of mean values of compound muscle action potential/sensory nerve action potential amplitude and conduction velocity between patients and their paired controls. CONCLUSION: This study supports the hypothesis that the origin of chronic sensory symptoms in PD patients is more central than peripheral.