Gait freezing and speech disturbance in Parkinson's disease

Gait freezing and speech disturbance are disabling axial features of Parkinson's disease (PD). However, the pathogenesis of these features remains unclear. We investigated the relation between changes in gait freezing and speech disturbance using visual and auditory cues in PD. 18 PD patients, comprising of 9 patients with freezing (PDGF) and 9 without gait freezing were studied. Patients performed a 7-m back-and-forth walk in a baseline state and with visual and auditory cues. Gait velocity, stride length and cadence were evaluated using a three-dimensional gait analysis system. For speech evaluation, patients read ten sentences in a baseline state and with visual and auditory cues. The time delay of speech initiation, speech rate and the number of repetitions per sentence were quantified. In PDGF patients, the increase in gait velocity positively correlated with the decrease in the time delay of the speech initiation. Also, the increase in the gait velocity and cadence positively correlated with the decrease in the number of repetitions per sentence. The increase in the stride length positively correlated with the increase in speech rate. Lastly, the increase in stride length positively correlated with the decrease in the number of repetitions per sentence. These findings suggest that there is a common pathomechanism of gait freezing and speech disturbance in PD.