Hirotaka Uchitomi

Interactive Rhythmic Cue Facilitates Gait Relearning in Patients with Parkinson's Disease

To develop a method for cooperative human gait training, we investigated whether interactive rhythmic cues could improve the gait performance of Parkinsons disease patients. The interactive rhythmic cues ware generated based on the mutual entrainment between the patients gait rhythms and the cue rhythms input to the patient while the patient walked. Previously, we found that the dynamic characteristics of stride interval fluctuation in Parkinsons disease patients were improved to a healthy 1/f fluctuation level using interactive rhythmic cues and that this effect was maintained in the short term. However, two problems remained in our previous study. First, it was not clear whether the key factor underpinning the effect was the mutual entrainment between the gait rhythms and the cue rhythms or the rhythmic cue fluctuation itself. Second, it was not clear whether or not the gait restoration was maintained longitudinally and was relearned after repeating the cue-based gait training. Thus, the present study clarified these issues using 32 patients who participated in a four-day experimental program. The patients were assigned randomly to one of four experimental groups with the following rhythmic cues: (a) interactive rhythmic cue, (b) fixed tempo cue, (c) 1/f fluctuating tempo cue, and (d) no cue. It has been reported that the 1/f fluctuation of stride interval in healthy gait is absent in Parkinsons disease patients. Therefore, we used this dynamic characteristic as an evaluation index to analyze gait relearning in the four different conditions. We observed a significant effect in condition (a) that the gait fluctuation of the patients gradually returned to a healthy 1/f fluctuation level, whereas this did not occur in the other conditions. This result suggests that the mutual entrainment can facilitate gait relearning effectively. It is expected that interactive rhythmic cues will be widely applicable in the fields of rehabilitation and assistive technology.

Relationship between Neural Rhythm Generation Disorders and Physical Disabilities in Parkinson's Disease Patients' Walking

Walking is generated by the interaction between neural rhythmic and physical activities. In fact, Parkinson’s disease (PD), which is an example of disease, causes not only neural rhythm generation disorders but also physical disabilities. However, the relationship between neural rhythm generation disorders and physical disabilities has not been determined. The aim of this study was to identify the mechanism of gait rhythm generation. In former research, neural rhythm generation disorders in PD patients’ walking were characterized by stride intervals, which are more variable and fluctuate randomly. The variability and fluctuation property were quantified using the coefficient of variation (CV) and scaling exponent α. Conversely, because walking is a dynamic process, postural reflex disorder (PRD) is considered the best way to estimate physical disabilities in walking. Therefore, we classified the severity of PRD using CV and α. Specifically, PD patients and healthy elderly were classified into three groups: no-PRD, mild-PRD, and obvious-PRD. We compared the contributions of CV and α to the accuracy of this classification. In this study, 45 PD patients and 17 healthy elderly people walked 200 m. The severity of PRD was determined using the modified Hoehn–Yahr scale (mH-Y). People with mH-Y scores of 2.5 and 3 had mild-PRD and obvious-PRD, respectively. As a result, CV differentiated no-PRD from PRD, indicating the correlation between CV and PRD. Considering that PRD is independent of neural rhythm generation, this result suggests the existence of feedback process from physical activities to neural rhythmic activities. Moreover, α differentiated obvious-PRD from mild-PRD. Considering α reflects the intensity of interaction between factors, this result suggests the change of the interaction. Therefore, the interaction between neural rhythmic and physical activities is thought to plays an important role for gait rhythm generation. These characteristics have potential to evaluate the symptoms of PD.

Interpersonal synchrony-based dynamic stabilization in walking rhythm of Parkinson's disease

Considerable research attention has been devoted to interpersonal synchrony and to locomotor control.

Interpersonal synchrony-based dynamic stabilization of the gait rhythm between human and virtual robot — Clinical application to festinating gait of Parkinson's disease patient

Recently, robotics attracts attention in field of not only industry and production but also assistive technology and rehabilitation method. It is required how the system generate assistive functions in interaction with the user, while lots of one-sided help forms are in previous researches. From these backgrounds, we have focused on cooperative gait between humans as interpersonal synchronization, and modeled the mechanism of footstep rhythm synchronization. Moreover, we developed an interpersonal synchrony emulation robot named Walk-Mate, which was biped virtual robot synchronizing with the users footstep rhythm via walking together. In this study, we evaluated the effect of Walk-Mate in stabilizing gait with Parkinsons disease (PD), which previously displayed disturbances in rhythm formation and festinating gait (accelerating footsteps). The results showed that the festinating gait, evaluated by stride time reduction rate, significantly stabilized and accelerated less with Walk-Mate compared to unassisted walking. Additionally, carry-over effects were significantly observed. After termination of the auditory stimulation, the gait remained stabilized. These suggested that gait with PD was dynamically stabilized by the interpersonal synchrony process between timing of humans gait and of external auditory cues. In this paper, we showed significant improvement for the festinating gait in the PD patients.

Improving gait performance in Parkinson's disease by interpersonal synchrony-based dynamic stabilization

Previously, research on gait control has mainly focused on interpersonal synchrony and locomotor control. However their intersection, the interpersonal synchronization of stepping rhythms which is widely observed in our daily life, remains relatively unexplored, despite being a common phenomenon that has considerable rehabilitation potential. Therefore, from the perspective of mutual entrainment of gait rhythms, we have constructed an interpersonal synchrony emulation system between a human subject and a biped virtual robot that generates pacing signal cues using nonlinear oscillators. This system synchronizes the stride interval times of a human and the robot in a cross-feedback manner; by presenting auditory stimulation that indicates the timing of the partners foot contacting the ground. Here, we evaluated the effectiveness of the system in gait stabilization of twenty-one Parkinsons disease (PD) patients, who previously displayed disturbances in rhythm formation and festinating gait (accelerating steps). The results showed that the festinating gait, as measured as stride time reduction rate, significantly stabilized and accelerated less with the system compared to unassisted walking. Additionally, significant carry-over effects were observed. After termination of the auditory stimulation, the gait remained stabilized. Our previous pilot study suggested that the gait of PD patients was dynamically stabilized by applying the inter personal synchrony process between the timing of humans gait and of external auditory cues. In this paper, we showed significant improvement for the festinating gait in twenty one PD patients.

Effect of Interpersonal Interaction on Festinating Gait Rehabilitation in Patients with Parkinson’s Disease

Although human walking gait rhythms are generated by native individual gait dynamics, these gait dynamics change during interactions between humans. A typical phenomenon is synchronization of gait rhythms during cooperative walking. Our previous research revealed that fluctuation characteristics in stride interval of subjects with Parkinson’s disease changed from random to 1/f fluctuation as fractal characteristics during cooperative walking with the gait assist system Walk-Mate, which emulates a human interaction using interactive rhythmic cues. Moreover, gait dynamics were relearned through Walk-Mate gait training. However, the system’s clinical efficacy was unclear because the previous studies did not focus on specific gait rhythm disorder symptoms. Therefore, this study aimed to evaluate the effect of Walk-Mate on festinating gait among subjects with Parkinson’s disease. Three within-subject experimental conditions were used: (1) preinteraction condition, (2) interaction condition, and (3) postinteraction condition. The only difference between conditions was the interactive rhythmic cues generated by Walk-Mate. Because subjects with festinating gait gradually and involuntarily decreased their stride interval, the regression slope of stride interval as an index of severity of preinteraction festinating gait was elevated. The regression slope in the interaction condition was more gradual than during the preinteraction condition, indicating that the interactive rhythmic cues contributed to relieving festinating gait and stabilizing gait dynamics. Moreover, the gradual regression slope was carried over to the postinteraction condition, indicating that subjects with festinating gait have the potential to relearn stable gait dynamics. These results suggest that disordered gait dynamics are clinically restored through interactive rhythmic cues and that Walk-Mate may have the potential to assist therapists in more effective rehabilitation. Trial Registration: UMIN Clinical Trials Registry UMIN000012591

Rhythm-fluctuation-based evaluation platform for gait training of Parkinson's disease patients

Gait training using rhythmic auditory cue showed training effect on gait dynamics of patients with Parkinsons disease (PD). On the other hand, 2 indicators of gait rhythm fluctuation, coefficient of variation (CV) and scaling exponent α, can evaluate severity of PD. However the gait training was not evaluated by both of these indicators at a time. In this paper, we aim to propose rhythm-fluctuation-based evaluation platform for gait training of PD patients. This platform consists of CV and α of stride interval. Specifically, we evaluated 3 types of gait training by calculating the change amount of CV and α. The training types are 1) interactive Walk-Mate (WM) gait training, 2) fixed-tempo Rhythmic Auditory Stimulation (RAS) gait training, and 3) Silent Control gait training. The training program was continued for 4 days. The first trial in each day was baseline walking trial without rhythmic cue. The second and the third trials were training trial corresponding to the training condition. Twenty-four PD patients walked for about 2 minutes in each trial. These patients divided into 3 groups about training type. As a result, WM gait training improved α and CV significantly. RAS gait training tended to improve CV, but it seemed to worsen a of gait rhythm. These effects of RAS gait training were marginally significant. However, Silent Control training did not show the significant effect on both of the indicators. From these results, the rhythm-fluctuation-based evaluation platform was successfully used to evaluate each type of gait training. In addition, the rhythm-fluctuation-based evaluation platform detected the difference between WM gait training and RAS gait training by α.