Dopa-Responsive Dystonia and gait analysis: A case study of levodopa therapeutic effects

IntroductionPatients suffering Dopa-Responsive Dystonia present dystonia, abnormal postural balance and gait impairment. Treatment with levodopa typically improves these three symptoms. The present study provides an extensive analysis of gait and posture in a patient with Dopa-Responsive Dystonia, prior to and during levodopa therapy.MethodThe patient was assessed with the Unified Dystonia Rating Scale, underwent motion analysis with an optoelectronic system and postural analysis with force plates.ResultsThis study provides a detailed quantification of gait parameters in a Dopa-Responsive Dystonia patient. Prior to treatment, mean walking speed was severely reduced, gait cadence and step length were decreased and stride width was increased. Right lower limb and pelvis showed kinematic defects, trunk and Centre of Mass were backwards. During levodopa therapy, the walking speed was doubled, gait cadence and step length were increased and stride width was reduced. Nearly all kinematic parameters of lower limbs were significantly improved. The patient’s Centre of Mass during gait and Centre of pressure in static position both shifted forward.ConclusionLevodopa dramatically decreased dystonia and improved spatio-temporal, kinematic and posture parameters. Our main pathophysiological hypothesis is that trunk tilt and its consequences on the Centre of Mass position have a pivotal influence on gait and balance, explaining both the initial impairments and the therapeutic effects. Gait analysis proves to be an effective tool to understand the pathophysiology of this patient, the therapeutic effects and mild residual gait defects in order to plan further rehabilitation strategy for this DRD patient. We propose that it will also prove to be useful for the exploration of other dystonic patients.