Gait disorders and balance impairments are one of the most incapacitating symptoms of Parkinson's disease (PD). Gait impairment in Parkinson's disease exists despite the use of dopinergic therapy. Motor phenotype associated with postural instability and ambulatory dysfunction is related to greater risk of motor decline and may be influenced by non-dopinergic pathology (Galna et al., 2015). Galna et al. (2015) conducted a study to document the progression of gait impairment over 18 months in individuals with Parkinson's disease with regard to phenotype and medication. Gait characteristics were measured in 121 PD and 184 controls, and 18 months later in 108 PD participants (Galna, 2015). Sixteen gait characteristics were examined with respect to five broad domains for PD and motor phenotype. Correlations between change in levodopa (l-dopa) equivalent daily dose and gait were used to identify dopa-responsive and nonresponsive characteristics (Galna, 2015). Pace and rhythm deteriorated over 18 months in people with PD, with other gait domains remaining stable. People with a postural instability and gait difficulty phenotype had more impaired gait at baseline compared with a tremor-dominant phenotype, which was most evident in temporal characteristics (Galna, 2015). In contrast, pace and variability deteriorated over the subsequent 18 months in the tremor-dominant phenotype only (Galna, 2015). Weak but statistically significant correlations were found between increased l-dopa medication and less deterioration in pace and asymmetry. Significant gait impairment is evident in very early disease despite optimal medication (Galna, 2015).