Assessment of speech and swallowing functions in pediatric dystonia and monitoring under deep brain stimulation

Abstract

Objective: Speech impairment and dysphagia are common in movement disorders such as Parkinson's disease; however, both are major features in different forms of dystonia. Despite the frequent cranial involvement in childhood onset dystonias, the assessment of specific symptoms such as dysarthria, dysphonia and dysphagia and the impact of therapeutics, has been only exceptionally addressed Our objective is to assess, in a group of pediatric dystonia patients recruited for deep brain stimulation (DBS), the proportion of patients presenting with dysphagia and speech impairment, relationship with underlying etiology and response to DBS. Methods: We retrospectively studied all pediatric cases under 17 who underwent DBS for generalized dystonia with cranio-cervical involvement, responsible for dysarthria, dysphagia and dysphonia. Clinical examination included the Burke-Fahn Marsden dystonia rating scale for assessment of speech and swallowing impairment. Water test and fiber optic endoscopic evaluation (FEES) of swallowing was available for several patients. The outcome of DBS effect on these three symptoms has been monitored. Results: Out of 120 pediatric generalized dystonia cases followed for bilateral pallidal DBS, 81 presented (67,5%) with cranio-cervical dystonia exhibiting dysphagia and or speech impairment. Major documented etiologies were Pantothenate kinase associated neurodegeneration (11 patients), mitochondiral enkephalopathy (8) and dyskinetic cerebral palsy secondary to hypoxic- ischemic enkephalopathy (19 patients). Both, dysphagia and speech impairment were more frequently associated in progressive disorders. Dysphagia was more frequently improved compared to speech impairment. In six patients, improvement of swallowing was sufficient enough to allow PEG suppression. Conclusion: When compared to Parkinson's disease, despite comparable speech and swallowing impairment in childhood dystonia (80% versus 67,5%) little is known about the impact of DBS. Our study document symptoms characteristics, severity and evolution under DBS therapy and provide arguments in favour of positive outcome in axial and limb dystonia but also in cranial involvement in a subgroup of patients.