Non-motor symptoms in patients with isolated dystonia: comparison between the age of onset

Abstract

Background: The etiology and motor presentation differs between pediatric- and adult-onset dystonia. Emerging evidence has demonstrated that non-motor symptoms are frequent in adult dystonia, which affect the quality of life. By contrast, little is known about the frequency and severity of such presentations in pediatric-onset individuals. Here, we investigated the motor and non-motor symptoms in a large cohort of Chinese patients with isolated dystonia and compared between pediatric-onset and adult-onset groups.Methods: In this retrospective study, 34 pediatric-onset patients and 197 adult-onset patients with isolated dystonia were recruited. Motor impairment was assessed by the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS). Non-motor symptoms were evaluated through several validated scales, including fatigue (by Fatigue Severity Scale, FSS), excessive daytime sleepiness (by Epworth Sleepiness Scale, ESS), sleep disturbance (by Pittsburgh Sleep Quality Index, PSQI), anxiety (by Beck Anxiety Inventory, BAI) and depression (by Beck Depression Inventory 21, BDI-21).Results: Generalized dystonia was more common in pediatric-onset patients and focal dystonia was more common in adult-onset patients (p < 0.001). Generally, the BFMDRS score in total pediatric-onset group was higher than adult-onset group (p = 0.002). No differences was found in BFMDRS score between pediatric-onset and adult-onset patients with cervical and multifocal subtype dystonia. Compared with adult-onset group, pediatric-onset group had a lower rate of sleep disturbance (p < 0.0001) and similar rates of fatigue, excessive daytime sleepiness, depression and anxiety. Logistic regression analysis on patients with cervical dystonia indicated that the adult-onset and motor severity were independently associated with increased odds of sleep disturbance (p = 0.03) and depression (p = 0.01), respectively.Conclusion: Pediatric-onset dystonia patients were less likely to display focal dystonia. Most non-motor symptoms in pediatric-onset patients were comparable to their adult-onset counterparts. Non-motor presentations may to some extent correlate with motor symptoms, but their underlying pathophysiology need to be investigated further.