Ludwig Maximilian University of Munich (LMU), Hauner Children’s Hospital, Paediatric Neurology and Developmental Medicine, Munich, Germany
| [b] Swiss Children’s Rehab, University Children’s Hospital Zurich, Affoltern am Albis, Switzerland
Correspondence to: PD Dr. Astrid Blaschek, Ludwig Maximilian University of Munich (LMU), Hauner Children’s Hospital, Pediatric Neurology, Developmental Medicine, Lindwurmstr. 4, 80337 Munich. Tel.: +49 89 4400 55110; Fax: +49 89 4400 55111; E-mail: [email protected].
Abstract: Background:Spinal Muscular Atrophy (SMA) is the most common neurodegenerative disease in childhood. New therapeutic interventions have been developed to interrupt rapid motor deterioration. The current standard of clinical evaluation for severely weak infants is the Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND), originally developed for SMA type 1. This test however, remains subjective and requires extensive training to be performed reliably. Objective:Proof of principle of the motion tracking method for capturing complex movement patterns in ten children with SMA. Methods:We have developed a system for tracking full-body motion in infants (KineMAT) using a commercially available, low-cost RGB-depth sensor. Ten patients with SMA (2–46 months of age; CHOP INTEND score 10–50) were recorded for 2 minutes during unperturbed spontaneous whole-body activity. Five predefined motion parameters representing 56 degrees of freedom of upper, lower extremities and trunk joints were correlated with CHOP INTEND scores using Pearson product momentum correlation (r). Test-retest analysis in two patients used descriptive statistics. Results:4/5 preselected motion parameters highly correlated with CHOP INTEND: 1. Standard deviation of joint angles (r = 0.959, test-retest range 1.3–1.9%), 2. Standard deviation of joint position (r = 0.933, test-retest range 2.9%), 3. Absolute distance of hand/foot travelled (r = 0.937, test-retest range 6–10.5%), 4. Absolute distance of hand/foot travelled against gravity (r = 0.923; test-retest range 4.8–8.5%). Conclusions:Markerless whole-body motion capture using the KineMAT proved to objectively capture motor performance in infants and children with SMA across different severity and ages.
Keywords: (4–10): Spinal muscle atrophy (SMA), 3D motion tracking, kinect, CHOP