The Frequency of Nonmotor Symptoms among Advanced Parkinson Patients May Depend on Instrument Used for Assessment

Background. Nonmotor symptoms (NMS) of Parkinson's disease (PD) may be more debilitating than motor symptoms. The purpose of this study was to determine the frequency and corecognition of NMS among our advanced PD cohort (patients considered for deep brain stimulation (DBS)) and caregivers. Methods. NMS-Questionnaire (NMS-Q), a self-administered screening questionnaire, and NMS Assessment-Scale (NMS-S), a clinician-administered scale, were administered to PD patients and caregivers. Results. We enrolled 33 PD patients (23 males, 10 females) and caregivers. The most frequent NMS among patients using NMS-Q were gastrointestinal (87.9%), sleep (84.9%), and urinary (72.7%), while the most frequent symptoms using NMS-S were sleep (90.9%), gastrointestinal (75.8%), and mood (75.8%). Patient/caregiver scoring correlations for NMS-Q and NMS-S were 0.670 ( ) and 0.527 ( ), respectively. Conclusion The frequency of NMS among advanced PD patients and correlation between patients and caregivers varied with the instrument used. The overall correlation between patient and caregiver was greater with NMS-Q than NMS-S. 1. Introduction It is becoming increasingly recognized that PD is a multidimensional disease and that nonmotor symptoms (NMS) can potentially affect quality of life as much or more than motor dysfunction [1]. NMS may be underrecognized by physicians and include such important features as cognitive impairment, depression, and apathy. A recent paper by Carter and colleagues found that NMS may contribute more to caregiver strain and depression than motor symptoms [2]. The NMS Questionnaire (NMS-Q) was devised to screen patients and was recently validated [3]. Subsequently, an NMS Assessment Scale for Parkinson’s disease (NMS-S) has been created to assess the frequency and severity of NMS in PD [4]. In a large, recent multicenter study by Barone and colleagues, 98.6% of PD patients had at least one NMS [5]. However, studies surveying NMS specifically in advanced PD patients have been limited. We suspected that, in this subset of PD patients, NMS may play even greater role and may be more prevalent. We chose a population with relatively advanced PD, and we aimed in this study to determine the frequency of NMS in PD patients and to evaluate the correlation between PD patient and caregiver perceptions of NMS. 2. Methods Consecutive advanced PD patients with severe motor fluctuations who were candidates undergoing evaluation for either unilateral STN or GPI stimulation were included. All patients signed informed consents to have their data stored in a database in