Evolution of the Motor Symptoms in Parkinson Disease under Auditory Stimulation

This paper describes a study that analyzes the effect of periodic binaural auditory stimulation in the beta band on two of the major motor symptoms of patients with Parkinson's disease (PD), resting tremor and bradykinesia. Participants included two groups of PD patients (n=21, age 63.69±7.43, stage 1.55±0.55 Hoehn & Yahr scale) that were exposed to an experimental (group A) or placebo (group B) auditory stimulation once a day, and a group of healthy controls (n=7, age 64.00±5.45) that was not exposed to any stimulation. The experimental stimulation consisted of 10min of binaural beats at 14Hz presented rhythmically and masked with pink noise, while the placebo stimulation consisted of pink noise only. All participants were monitored using wearable devices and mobile phones to assess the evolution of resting tremors and bradykinesia. Both indicators were obtained from accelerometer signals during the execution of specific motor tasks extracted from the MDS-UPDRS scale Part III once a week. The results show a significant difference between the group of healthy controls and PD patients for the resting tremor and bradykinesia indicators, suggesting the predictive validity of the monitoring system and the consistency of the indicators. Regarding the effect of auditory stimulation, a reduction in the level of resting tremor was observed in patients who received the experimental stimulation compared to those who received the placebo stimulation (p=0.004) over the course of the 8 weeks of monitoring. However, no improvement in bradykinesia was observed. The generalization of results is compromised due to a set of limitations that have been identified, so guidance is provided that might contribute to improving future experimental designs in similar studies.