Objective extraction of movement features prompting expert-identification of dystonia in ambulatory children with cerebral palsy

Aim: To determine the specific movement features in children with cerebral palsy (CP) that prompt expert identification of dystonia Methods: Dystonia identification in CP, particularly when co-morbid with spasticity, can be difficult. For this retrospective case-control study, we conducted a qualitative thematic analysis of consensus-building discussions between three pediatric movement disorders physicians as they attempted to identify the presence or absence of dystonia in gait videos of 40 subjects with spastic CP and periventricular leukomalacia. Results: Initial unanimous consensus regarding the presence or absence of dystonia was achieved in 12 videos (30%). Following consensus building discussion, 22 additional videos (55%) yielded unanimous consensus. Two main themes were generated: 1) Unilateral leg or foot adduction that was variable over time, and 2) Difficulty in identifying dystonia. Codes contributing to Theme 1 were more likely to appear when a discussant was favoring the presence of dystonia in a video (Chi-square, p=0.004). Discussion: These results provide specific movement features that could aid dystonia diagnosis in ambulatory children with CP. However, these results also suggest that, even amongst putative motor phenotyping experts, visual dystonia diagnosis in CP remains difficult, highlighting the need for developing and using objective dystonia diagnosis measures.