Fatigue, Sleep Disturbances, and Their Influence on Quality of Life in Cervical Dystonia Patients

Abstract

Nonmotor symptoms (NMS) are highly prevalent in cervical dystonia (CD). In general, fatigue and sleep are important NMS that determine a decreased health-related quality of life (HR-QoL), but their influence in CD is unknown. The authors systematically investigated fatigue, excessive daytime sleepiness (EDS), and sleep quality in patients with CD and controls and assessed the influence of psychiatric comorbidity, pain, and dystonia motor severity. They also examined the predictors of HR-QoL. The study included 44 patients with CD and 43 matched controls. Fatigue, EDS, and sleep quality were assessed with quantitative questionnaires and corrected for depression and anxiety using analysis of covariance. The Toronto Western Spasmodic Torticollis Rating Scale and the Clinical Global Impression Scale-jerks/tremor subscale were used to score motor severity and to assess whether motor characteristics could explain an additional part of the variation in fatigue and sleep-related measures. HR-QoL was determined with the RAND-36 item Health Survey, and predictors of HR-QoL were assessed using multiple regression. Fatigue scores were increased independently from psychiatric comorbidity (4.0 vs. 2.7; P<0.01), whereas EDS (7.3 vs. 7.4; P=0.95) and sleep quality (6.5 vs. 6.1; P=0.73) were highly associated with depression and anxiety. In patients with CD, motor severity did not explain the variations in fatigue (change in the correlation coefficient [ΔR2]=0.06; P=0.15), EDS (ΔR2=0.00; P=0.96), or sleep quality (ΔR2=0.04; P=0.38) scores. Fatigue, EDS, psychiatric comorbidity, and pain predicted a decreased QoL. Independent from psychiatric comorbidity and motor severity, fatigue appeared to be a primary NMS. Sleep-related measures were highly associated with psychiatric comorbidity, but not with motor severity. Only NMS predicted HR-QoL, which emphasizes the importance of attention to NMS in patients with CD.