Freezing of gait associated with gait asymmetry

Freezing of gait (FOG) in advanced Parkinson's disease (PD) may be related to gait assymmetry and bilateral coordination of the legs during gait, according to a recent study. The motor performance of 24 patients with PD who experience FOG episodes (PD+FOG) was compared to that of 12 patients with PD who did not (PD-FOG). Patients were tested in an unmedicated and medicated state. The investigators explain their reasons for examining whether uncoordinated bilateral motor performance during gait was involved in FOG. They say, "First, if impairment in the timing and pacing of movement that involves both legs takes place, as in FOG, an impaired coordination of sequencing and timing of the activation of each leg may contribute to the deficiency. Second, a few investigations describe empirical evidence supporting the notion of asymmetric motor performance in FOG."The patients were instructed to walk at their normal pace on level ground for a total of 80 metres. Force-sensitive insoles were placed in participants' shoes to determine parameters such as swing time of each foot during strides, variability in swing and the foot with the shorter and longer mean swing times. These parameters were then used to calculate gait asymmetry. Asymmetry in the upper extremities was also measured, using UPDRS scores, to determine whether differences in gait asymmetry were unique to walking of part of general motor control disturbance.The results showed that the differences in swing times between the feet were greater in PD+FOG than in PD-FOG in both the medicated and unmedicated states. In addition, unlike in PD-FOG, PD+FOG patients' variability in swing time in one foot was not correlated with variability in the other foot. The authors report that there was no difference between the two groups regarding asymmetry in scores of the AUPDRS tests, suggesting that gait asymmetry is not a direct reflection of asymmetry in PD symptoms. Reference...