Dissertation/Thesis Abstract

Parkinsonian gait characterization and vibratory intervention
by Winfree, Kyle Nathan, Ph.D., University of Delaware, 2013, 259; 3598770
Abstract (Summary)

Parkinson's disease is a degenerative neurological disease that often impacts older adults, leading to difficulties with transfers, posture, balance, and walking. Approximately half of those with Parkinson's disease develop the symptom of freezing of gait, a condition that makes initiating walking difficult. This leads to loss of independence, fear of falls, injuries, inactivity resulting in social isolation, and increased risk of osteoporosis. Pharmacological therapy provides relief to only some of the neurological symptoms in Parkinson's disease. However, gait, posture, balance, and freezing of gait obtain little benefit from drug treatments.

Research suggests visual, auditory, and vibratory cueing methods may improve some features of gait. However, visual cueing techniques often require modification of the environment, which is not possible in the community setting. Auditory cueing techniques can be executed with the use of headphones, but this can quickly become a problem, as it becomes a safety concern when it interferes with hearing environmental sounds. Studies of whole body vibration and studies of segment level vibration have demonstrated improvements to walking speed, step duration, step length, and gait variability. However, most studies have only focused on the immediate effects of vibration therapy.

To assess the impact of vibration as an intervention, we have designed the hard- ware, software, therapy protocol, and conducted a series of studies for this dissertation. The hardware is designed as a segment level device, which can be worn by a user and both provides the vibratory stimulation and measures parameters of gait. We call the device the PDShoe. Three force sensors are embedded into the insole the shoe worn by subjects. Two tactor actuators are placed between the shoe and subject's skin. Upon heel contact with the floor, a tactor placed at the heel begins to vibrate at a predetermined frequency and amplitude. Likewise, when the lateral metatarsal head or hallux of the foot contact the floor, a tactor placed over the metatarsal heads begins to vibrate. Vibration is only provided with the foot is in contact with the floor; this is step synchronized vibration. Data is transferred via a wireless network in real time to a host computer where it is stored for later analysis. Parameters of the vibratory stimulation can be set on the PDShoe from the host computer. Data analysis is performed in a numerical analysis environment, where the time series force data is cut into individual steps. Eight parameters of gait are extracted from each of these steps, providing mean and variability measures for each subject.

To test the efficacy of step synchronized vibration, we conducted two studies with healthy subjects and four studies with Parkinson's disease subjects. Accuracy and reliability of the device was established and included the use of change point analysis and correlation with the 10-meter Walk Test. Using the PDShoe system without vibratory feedback, we successfully characterized the gait of healthy persons over fifty years old. Subsequently we tested the feasibility, safety, and impact of our step synchronized vibration protocol with healthy subjects. Our protocol was easily implemented, well tolerated, and there were no adverse events. As was expected, no impact from the step synchronized vibration was seen with the healthy subjects. We then performed a feasibility and impact study with Parkinson's disease subjects. Again the protocol was easily implemented, well tolerated, and no adverse events were noted. A difference between pre- and post-intervention clinical scores of the Freezing of Gait Questionnaire, Berg Balance Scale, Timed Up and Go and gait measures of step and stance duration were found. Next, we conducted a clinical study with eight subjects at the All India Institute of Medical Sciences. This study demonstrated that subjects who exhibited the symptom of freezing of gait received the greatest benefit from the step synchronized vibration. These results informed a follow up study on seventeen subjects, all of whom had the symptom of freezing of gait. This last study demonstrated positive improvements in clinical measures of the Freezing of Gait Questionnaire, Berg Balance Scale, Timed Up and Go, Walking Speed, and gait characteristics of step duration, stance duration, swing duration, heel max force timing, and heel contact duration. There is encouraging evidence for further investigation; this data will be used to inform future studies.

These studies demonstrated the functionality, reliability, validity of the PDShoe device to measure characteristics of gait. Impact was demonstrated in three studies with Parkinson's disease subjects.

Indexing (document details)
Advisor: Agrawal, Sunil K.
Commitee: Glutting, Joseph, Miller, Freeman, Pretzer-Aboff, Ingrid A.
School: University of Delaware
Department: Biomechanics and Movement Science
School Location: United States -- Delaware
Source: DAI-B 75/02(E), Dissertation Abstracts International
Source Type: DISSERTATION
Subjects: Biomedical engineering, Biomechanics, Bioinformatics
Keywords: Gait characterization, Parkinson's disease, Synchronized vibration, Vibration interventions
Publication Number: 3598770
ISBN: 9781303475993
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