Validation of a new scale for the evaluation of sialorrhea in patients with Parkinson's disease.

Sialorrhea is common in Parkinson disease (PD), affecting approximately 70% to 75% of patients. Several tools for measuring saliva volume or production exist, but none are designed specifically for assessing sialorrhea-related discomfort. The objective of this study was to develop and validate a clinical scale for subjective evaluation of sialorrhea in PD. In Phase I, internal consistency of the Sialorrhea Clinical Scale for PD (SCS-PD) was established in 39 PD patients. In Phase II, scale validity was proven through saliva volume measurements obtained in 49 PD patients and 27 healthy volunteers. Internal consistency estimated using Cronbach's alpha was 0.78, indicating none of the original seven items tested needed to be removed. Twenty-one patients complaining of sialorrhea (63%) studied during Phase II, showed higher SCS-PD scores but no differences in saliva volume. SCS-PD scores showed significant correlation with saliva volume (r = 0.41; P = 0.004) and with total Unified Parkinson's Disease Rating Scale Part III (UPDRS III) scores (r = 0.70). Furthermore, saliva volume showed inverse relation to age in PD patients as well as in controls (r = -0.3 and r = -0.4; P < 0.05), but SCS-PD scores did not. The SCS-PD scale showed good internal consistency and validity, providing support for its use in routine clinical sialorrhea-related discomfort evaluation. Copyright 2006 Movement Disorder Society.