The impact and prognosis for dystonia in childhood including dystonic cerebral palsy: a clinical and demographic tertiary cohort study

Abstract

Introduction and methods: The impact of dystonia in childhood is poorly understood. We report our experience of referrals between 2005 and 2012.

Results: Of 294/315 assessable children, 15/294 had pure spasticity, leaving 279/294 with dystonia classified as primary (30/279:10.7%); primary-plus (19/279:6.8%) and secondary (230/279:82.4%) dystonia, including heredodegenerative dystonia (29/279:10.3%); 150/279 (53.7%) with cerebral palsy and 51/279 (18.2%) acquired brain injury. Definitive diagnoses were available in 222/294 (79.6%), but lower in primary/primary-plus compared with secondary groups (11/49 vs 211/230: Fisher's exact test p<0.0001). Spasticity comorbidity was present in 79/230 (34.3%) children. Median age (interquartile years) at referral was 9.75 (6.58-13), not significantly differing by aetiology (Kruskal-Wallis test p>0.05); dystonia-onset age was 3 (0.5-7.0) for primary/primary-plus and 0.25 (0.08-0.8) in the secondary/CP groups. Dystonia duration at referral was 4.75 years (3.0-10.33) for primary/primary-plus groups and 7.83 (5.4-11) in the secondary group. The mean (interquartile range) proportion of life lived with dystonia, derived as dystonia duration normalised to age was 0.68 (0.31-0.96); 0.59 (0.35-0.8); 0.75 (0.62-0.95)and 0.9 (0.92-0.99) for primary, primary-plus, heredodegenerative and secondary-static dystonias respectively. Only 91/279 (32.6%) experienced a period of normal motor development. Carers perceived dystonia deterioration in 168/279 (60.2%), stabilisation in 88/279 (31.5%) and improvement in 23/279 (8.2%). Dystonia occurred in 26/225 (11.6%) siblings: 14/26 secondary and 5/26 heredodegenerative dystonia. Comorbidities were identified in 176/279 (63.1%) cases. Gross Motor Function Classification System (GMFCS) levels I-III were commoner in primary/primary-plus (37/49: 75%) compared with secondary/CP (29/230:13%) cases, χ(2) p<0.0001).

Discussion: In this selective cohort, childhood dystonia is severe, presenting early before worsening without remission. Secondary dystonias spend a higher proportion of life living with dystonia and lower functional capacity. Despite referral bias, services offering neurosurgical interventions and health service planning agencies should understand the context and predicament of life with childhood dystonia.

Keywords: Cerebral Palsy; Dystonia; Movement Disorders; Paediatric Neurology; Spasticity.