Dystonia during hand activity in children with spastic unilateral cerebral palsy, an observational study

Background: Spasticity and dyskinesia are motor signs that co-exist in cerebral palsy (CP). It is well accepted that, in spastic bilateral CP, dystonia can be present in addition to spasticity, and equally that spasticity is often present in individuals with dyskinetic CP. In unilateral spastic CP, dystonia of the upper extremity is only rarely identified or addressed. The aim of this study was to investigate if dystonia was present in the hand of children with unilateral spastic CP, and, if present, to what extent, and when it was first noticeable. Method: Ninety-seven children with unilateral spastic CP, born 1999-2014, with standardized digital films of hand function from Assisting Hand Assessments (AHA), were included. Films were reviewed, and presence or absence, of dystonia and choreoathetosis were scored by three experienced raters.Results: Dystonia in the hand was present during activities in 70% (68/97) of the children at a mean age of 12 years (SD 4,4). In 74% (50/68) of these children, dystonia was present more than 50% of the evaluated time. For 63% (43/68) more than one digital recording at younger ages were available. Dystonia could first clearly be observed at a mean age of 3,8 years. Choreoathetosis was observed in 7% (5/68) of the children with dystonia. Children without dystonia had significantly higher (corresponding to better function) AHA units (median: 75, 25th -75th: 45-82) in comparison to children with dystonia (median: 57, 25th -75th: 52-63) (p = 0.01).Conclusion: Dystonia in the hand is common in unilateral CP and correlates to lower hand functioning.