Motion analysis of stereotyped hand movements in Rett syndrome

Background Rett syndrome is a genetic developmental disorder, and stereotyped hand movements are a striking feature of this condition. The aim of the present study was to subject these movements to objective analysis and compare the results in one girl at different ages. Method The hand movements of a 10-year-old girl with Rett syndrome were subjected to accurate, three-dimensional (3D) computerized motion analysis and compared to two-dimensional (2D) video analysis of the same girl at 3 years of age. Results Three-dimensional computerized analysis revealed regular patterns with strong coupling between the hands. Frequency analysis showed a dominant frequency at 1.2 Hz, with a higher component at 2.4 Hz that may relate to the activity of basic rhythm generators. The same coupling characteristics were extracted from standard, 2D video recordings made at the same time as the 3D capture. Conclusion An informal video of the same girl taken when she was 3 years of age was analysed in the same way as the 2D video and showed the same characteristics, indicating the possible future use of automated video analysis for early screening and intervention evaluation.