Jessica Rose

Research Interests

Dr. Rose's research focuses on the neuromuscular and musculoskeletal mechanisms underlying gait abnormalities in children with cerebral palsy (CP) and other pediatric orthopaedic conditions. As director of the Motion & Gait Analysis Lab at Lucile Packard Children's Hospital, research has focused on the energy cost of walking, muscle pathology, selective motor control, postural balance and motor-unit firing in CP. Recent research investigates the relations between neonatal microstructural brain development on diffusion tensor MRI and later gait and motor deficits in very low birth weight preterm children.

This line of research began with investigations into the energetics of walking in CP, which prompted research on muscle pathophysiology in spastic CP (Rose et al, J Orthop Res, 1994). This histologic and morphometric biopsy study of spastic muscle in children with diplegia, found an abnormal predominance of type 1 fibers and abnormally high fiber diameter variability. These structural abnormalities, similar to changes seen with experimental chronic low frequency stimulation, may reflect an ongoing process of hypertrophy and atrophy and suggest that in spastic CP there may be a reduction in motor-unit firing rates, presumably as a result of the interrupted descending signals.

To further investigate these findings, a study was carried out to characterize neuromuscular activation and motor-unit firing characteristics in gastrocnemius and tibialis anterior muscles in spastic CP (Rose and McGill, Dev Med Child Neurol, 2002). Maximal voluntary neuromuscular activation, the ratio between maximal voluntary EMG amplitude and M-wave amplitude, was found to be substantially reduced in subjects with CP and was 24% of control values for tibialis anterior and 34% of control values for gastrocnemius. Motor-unit firing rates and recruitment were found to be normal at the lower levels of contraction tested, analysis of higher levels require technical...