Comorbidity of the nonmotor symptoms of Parkinson's disease

Many patients with Parkinson's disease (PD) have clinically significant anx iety, depression, fatigue, sleep disturbance:, or sensory symptoms. The com orbidity of these nonmotor symptoms and their relationship to PD severity h as not been extensively evaluated, Ninety- nine nondemented PD patients wer e evaluated with the following battery of tests: Beck Anxiety Inventory (BA I), Beck Depression Inventory (BDI), Fatigue Severity Scale (FSS), Pittsbur gh Sleep Quality Index (PSQI), a sensory symptom questionnaire, Unified Par kinson's Disease Rating Scale (UPDRS), Hoehn & Yahr (H/Y) Stage, and the Sc hwab & England ADL scale (S/E). The comorbidity of the nonmotor symptoms an d their relationship to PD severity was analyzed. Thirty-six percent of the study population had depression (BDI greater than or equal to 10), 33% had anxiety (BAI greater than or equal to 10), 40% had fatigue (FSS > 4), 47% had sleep disturbance (PSQI > 5), and 63% reported sensory symptoms. Only 1 2% of the sample had no nonmotor symptoms. Fifty-nine percent of the patien ts had two or more nonmotor symptoms, and nearly 25% had four or more. Incr eased comorbidity was associated with greater PD severity (P < 001). This s tudy reveals that the nonmotor symptoms of PD frequently occur together in the same patients. Increased comorbidity of the five nonmotor symptoms was associated with greater PD severity. These results suggest that recognition of these diverse nonmotor symptoms may be enhanced by looking for others w hen one nonmotor symptom has been identified. (C) 2001 Movement Disorder So ciety.