Non-motor manifestations in essential tremor: Use of a validated instrument to evaluate a wide spectrum of symptoms

Introduction: Recent studies suggest an association between non-motor symptoms and essential tremor (ET). Few studies have assessed psychological symptoms in ET. These studies were limited to western white populations and utilized scales that were specific to only one or two psychiatric domains. By contrast, the Symptom Checklist-90R (SCL-90R) is a validated clinical scale to screen for symptoms related to a spectrum of nine different psychological domains. Objective: To determine whether a wide spectrum of non-motor manifestations is associated with ET in patients in an Asian cohort. Methods: Consecutive ET patients and a group of control subjects were evaluated using the SCL-90R, which is comprised of items in nine major symptom dimensions and three global indices, including the positive symptom distress index. Results: ET patients (N=84) and controls (N=78) were similar in age (50.0±18.0 vs 46.0±14.4 years), gender and other demographic variables. ET patients had higher scores in three of nine major symptom dimensions: anxiety, phobic anxiety (p<0.0005) and psychoticism (p=0.005). In multivariate analysis, the anxiety (p<0.0005) and the positive symptom distress index scores (p<0.0005) were greater in ET patients compared to controls after adjusting for sex, age, marital status and educational level. The severity, but not duration of ET was correlated with the severity of anxiety symptoms. Conclusions: Utilizing the SCL-90R, we highlighted that ET patients reported more non-motor symptoms than healthy controls. The more frequent occurrence of anxiety symptoms in our Asian cohort extends the observation that such non-motor manifestations should be considered in the clinical management of ET.