TEMPORAL AND SPATIAL CHARACTERISTICS OF GAIT WHILE PERFORMING THE DYNAMIC GAIT INDEX IN PERSONS WITH AND WITHOUT BALANCE AND VESTIBULAR DISORDERS

Abstract

Purpose/Hypothesis: Persons with balance and vestibular disorders complain of difficulty walking, especially with head movement. The Dynamic Gait Index (DGI) is comprised of an observational battery of 8 walking tasks that allows a clinician to evaluate the impact of head movements plus speed and direction changes on gait performance. The underlying temporal and spatial aspects of gait that are associated with the DGI are unknown. The purpose of this study was to describe the temporal and spatial gait characteristics that are associated with gait dysfunction during performance of level walking items of the DGI in persons with and without balance and vestibular dysfunction. Number of Subjects: Forty seven subjects (mean age: 59.2 years, s.d. 18.5, range 24–90) participated in a descriptive cross sectional study (26 control subjects and 21 persons with balance and/or vestibular dysfunction). Materials/Methods: Tree trials of each level gait item were administered to subjects as they ambulated on a 13.5 meter instrumented (GAITrite) walkway. Temporal and spatial gait characteristics were measured using GAITRite software (Version 3.4). Test-retest reliability [Intra class correlation coefficient (ICC 3,1)] across three trials was determined for gait parameters associated with continuous walking (velocity, cadence) and the item requiring turning and stopping quickly (number of steps, ambulation time). Step length variability (coefficient of variation) was calculated. Mean gait parameter differences between control subjects and patients were compared using an independent sample t-test. Results: The ICCs (velocity, cadence) for all DGI items except turn and stop varied between 0.92–0.99. The ICC for the turn and stop item for the number of steps was 0.68 and ambulation time was 0.70. There were no patient/control differences in test-retest reliabilities on the DGI items that required continuous walking. Ambulation time on the walk, turn and stop showed significantly greater reliability in patients versus controls. For the continuous walking items, control subjects demonstrated significantly higher mean velocities and cadence than persons with vestibular dysfunction (p<;0.05). For the turn and stop item, there were no differences between the two groups on ambulation time (p=0.06) or step count (p=0.31). Patients demonstrated greater step length variability for walking with head movements, changing speeds and stepping over objects. Patients had a significantly greater mean base of support at heel strike for level walking, walking with head movements and stepping over objects. Conclusions: The temporal and spatial gait parameters underlying dynamic gait, as defined by the DGI, demonstrated good to excellent test-retest reliability and internal structure validity. Clinical Relevance: With enhanced knowledge of underlying gait abnormalities, targeted interventions can be developed to best remediate gait dysfunction in persons with vestibular disorders.