Tandem gait is widely used to assess a variety of neurologic and vestibular diseases. Tandem gait has been reported to predict fall risk in idiopathic Parkinson’s disease (PD) and help distinguish it from other forms of parkinsonism. We previously showed that tandem gait step-width widens with increasing Hoehn and Yahr (H&Y) disease severity. The change in specific tandem gait parameters in PD patients over time could contribute to understanding the pathology of the disease.

Tandem gait was collected using an instrumented gait mat in 50 PD participants and 21 controls at six-month intervals over a period of at least 24 months. The PD participants were further grouped based on their H&Y staging into stage 1, stage 2, or stage ≥ 2.5. The mean of the tandem gait variables step-width, step-length, step-time, and step-velocity were determined at each visit and the annual percent change in each variable for each participant over time was calculated. A student’s t-test was used to compare groups.

Compared to controls (1.44±2.18), the mean rate of increase of step-width was found to be significantly faster in H&Y stage 2 participants (11.47±4.35, p=0.04) and H&Y stage 2.5+ participants (15.97±5.47, p=0.03), but not in H&Y stage 1 participants (6.43±7.00, p=0.5). No significant difference in progression was found between controls and any H&Y group for the other 3 variables.