From qualitative to quantitative assessment of dystonia and choreoathetosis in childhood

The general aim of this doctoral project was to increase our insights into the qualitative and quantitative assessment methods for childhood-onset dystonia and choreoathetosis. Dystonia and choreoathetosis are movement disorders that interfere with activities of daily living and have a tremendous impact on quality of life. Dystonia and choreoathetosis can occur in children after a brain lesion near birth, as a consequence of a genetic defect, or without known origin, but its assessment is complicated due to the multi-faceted presentation of both movement disorders, especially if they present concurrently. For the qualitative part of this project, we focused on the assessment of dystonia and choreoathetosis using the dyskinesia impairment scale (DIS). This scale was specifically developed to assess dystonia and choreoathetosis in individuals with dyskinetic cerebral palsy. We expanded our focus towards individuals with inherited or idiopathic dystonias, since there is currently no assessment tool available that evaluates both individuals with primary and secondary dystonia. For the quantitative part of this project, we focused on upper limb movements, since many individuals with dyskinetic cerebral palsy can perform simple upper limb tasks. We implemented an instrumented assessment protocol using different methodologies during functional upper limb tasks in individuals with dyskinetic cerebral palsy. In chapter one, we explored the reliability and validity of the DIS in individuals with inherited and/or idiopathic dystonia to evaluate whether the DIS can be used to asses presence and severity of dystonia and choreoathetosis in this group. We found excellent inter-rater reliability for the total DIS scores and the dystonia subscale amongst three raters, indicating that presence and severity of dystonia can be reliably assessed in individuals with inherited or idiopathic dystonia. Inter-rater reliability for the presence and severity of choreoathetosis was somewhat lower, but still good. The lower inter-rater reliability for choreoathetosis could be attributed to lower presence of choreoathetosis in our study sample, and thus a higher presence of 'zeros', signifying absence of choreoathetosis. All scores showed high test-retest reliability, indicating that the DIS is a reliable scale to assess presence and severity of dystonia and/or choreoathetosis over time in a study sample with primary dystonia. This is important if we wish to use this scale to assess the