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

(1) Purpose In gait disorder of Parkinson's disease patient, the short-stepped gait which shows decreasing step length, the festinating gait which shows gradually decreasing stride interval, and the freezing of gait which shows hesitating foots' movement are well known. It is considered that these gait disorders are caused by decreasing dopamine secretion from a midbrain substantia nigra, the malfunction of basal ganglia is exhibited, and then an obstacle of the internal rhythm generation is developed. Although such a symptom is improved by medication treatment to some extent, the symptom is not completely restored and is worsened by progress of illness.
Therefore, the method for assisting the above medication treatment is expected that compensates the disordered internal rhythm generation with presentation of external rhythmic cue and improves motor control in gait with facilitating stable rhythm generation. Against the background, the purpose of this study was to develop a new motor assist technology for improving gait function by presentation of interactive rhythmic cue that is easy to synchronize the gait rhythm of the patient.
(2) Method It is a familiar experience to synchronize gait steps between persons when walking together with someone. Co-researcher Dr. Miyake (Tokyo Institute of Technology) has been studying interpersonal synchronization (mutual entrainment) of gait rhythm between persons. He is developing the gait support system, named Walk-Mate, that emulates cooperative gait between a person and a virtual robot. In concreate, the virtual robot in Walk-Mate system, which is implemented in a computer, detects the person's step timing, synchronizes the robot's step timing to the detected person's step timing, and provides interactive rhythmic cue to the person. Walk-Mate system is utilized in the rehabilitation of the gait disorder due to the hemiplegia and the hip osteoarthritis so far. An effect of Walk-mate system on improving the asymmetric property or gait stability of gait was clarified in previous studies.
This study utilizes such an assist system to facilitate the gait of Parkinson's disease patient for the first time. In concreate, the study focuses on festinating gait which is one of the pathognomonic symptoms. In the study, the independent gait of Parkinson's disease patient and the cooperative gait between the patient and Walk-Mate system are compared.
(3) Subjects The festinating gait is more likely to lead to a fall in a gait disorder of Parkinson's disease patients. Then, the festinating gait causes to break a bone from the fall, thereby leading to make the patients be bedridden. It is greatly beneficial for Parkinson's disease patients to develop the improvement method of gait disorder.
Therefore, the target subject is the Parkinson's disease patients with festinating gait in the study. Especially, in order to evaluate the effectiveness for gait assist, the study basically recruits the patient having the ability of walking alone.
(4) Clinical Study Protocol in Experiment -Each subject walks with hearing rhythmic cue which is provided from headphones.
-The stride interval of the subject was detected by foot sensors attached under the shoes of the subject.
-The subject walks with wearing Walk-Mate system for a few minutes.
-The subject does NOT wear any other experimental systems which output physical forces generated by actuator.

PC (virtual robot)
Foot Sensor Foot Sensor PC (virtual robot)

Headphones
Step sound Step timing