The Measurement of Postural Sway and Dynamic Gait Index as a Indication of Balance Before and After Vestibular Rehabilitation Therapy: A Case Study




Hartley, Kristina
Patterson, Rita
Lee, Yein
Kennedy, Shawn


0000-0003-4869-7276 (Hartley, Kristina)

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Background: When managing patients with Benign Paroxysmal Positional Vertigo (BPPV), many clinicians follow patients' rehabilitation outcomes by tracking the patients' subjective symptoms, such as a sense of disequilibrium, postural imbalance, and gait disturbances. Postural sway data measurements are used to evaluate static and dynamic balance capacity in various contexts, including symptoms of vertigo. In comparison, Dynamic Gait Index (DGI) is a functional measure of dynamic balance often used in vestibular rehabilitation therapy (VRT). This case study examines the possible correlation of the patient's postural sway data with their subjective onset, symptoms resolution, and DGI score.

Case Presentation: A 58-year-old female presented to the outpatient office with a new symptom of dizziness and subjective gait disturbances. The patient described the dizziness as similar to "room spinning." Symptoms worsened with head movement and resolved after a few seconds of no head movement. She also noticed the dizziness while lying down and turning in bed at night. Associated symptoms included a right-sided temporal headache and hearing difficulty. The patient's physical exam revealed normal findings except for the following. The patient's gait showed flexed forward posture and a broad base of support. Speed was slow, with uneven stride lengths. The neurological exam showed new onset nystagmus only 1-2 beats bilaterally. The pursuit was slow without apparent saccadic movements. The left hallux showed dorsiflexor movement, while the right displayed plantar flexor movement with Babinski. With the physical exam findings, BPPV was diagnosed, but before starting VRT, MRI was performed due to the new neurological findings. The MRI revealed a chronic lacunar infarct in the right caudate nucleus of unknown onset since her last visit. The patient was referred to her primary care physician for appropriate neurology referral and secondary prevention. Meanwhile, the patient was cleared to start VRT to address persistent vertigo. DGI was obtained two times during VRT, and an objective evaluation of sway was collected each time patient presented to the clinic before and after VRT. The sway data was collected by asking the patient to quietly stand on a Bertec force plate (Bertec, Columbus, Ohio) for 30 seconds with their eyes open (EO) and eyes closed (EC). A total of 21 sway measurements were calculated to evaluate objective changes in balance. The variables derived from the patient's Bertec force plate data were graphed per visit and analyzed via t-test for significance in comparison to DGI, age (age bracket [50-70]), height (1.67 m range, +-10%), and weight (90.45 kg range, +-15%) matched control data from the Human Performance Lab at UNTHSC. Significant changes in sway measurements were found in EC data over 7 weeks of therapy.

Conclusions: The DGI displayed minimal change throughout VRT. The DGI evaluation time (15 minutes) prevents it from being implemented during a clinic visit, whereas postural sway collection (2 minutes) can be integrated into the patient intake. This report indicates the possible utility of outpatient collected sway data as an objective measure of balance in evaluating and managing patients presenting with balance and gait difficulties.