Carlo N Rinaudo1, Michael C Schubert2, Phillip D Cremer3, William V C Figtree4, Christopher J Todd4, Americo A Migliaccio5. 1. MChiro, Balance and Vision Laboratory, Neuroscience Research Australia, Sydney, NSW, Australia. 2. Department of Otolaryngology-Head and Neck Surgery, Laboratory of Vestibular Neuro-Adaptation, Johns Hopkins University School of Medicine, Baltimore, Maryland. 3. Balance and Vision Laboratory, Neuroscience Research Australia, and Royal North Shore Hospital, Sydney, Australia. 4. Balance and Vision Laboratory, Neuroscience Research Australia, and University of New South Wales. 5. Balance and Vision Laboratory, Neuroscience Research Australia, Cnr Barker Street & Easy Street, Randwick NSW 2031, Sydney, Australia.
Abstract
BACKGROUND AND PURPOSE: Traditional vestibular rehabilitation therapies are effective in reducing vestibular hypofunction symptoms, but changes to the vestibulo-ocular reflex (VOR) are minimal. This controlled case report describes an increase in VOR after 6 months of incremental VOR adaptation (IVA) training in a person with chronic unilateral vestibular hypofunction. CASE DESCRIPTION: The participant was a 58-year-old female with a confirmed (Neurologist P.D.C.) left vestibular lesion stable for 2 years prior to entering a clinical trial examining the effects of daily IVA training. She was evaluated monthly for self-reported symptoms (dizziness handicap inventory), VOR function (video head impulse test), and VOR behavior (Dynamic Visual Acuity test). Intervention consisted of 6 months of 15 minutes per day unassisted training using the IVA training regime with a device developed in our laboratory. The take-home device enables the VOR response to gradually normalize on the ipsilesional side via visual-vestibular mismatch training. The intervention was followed by a 6-month wash-out and 3-month control period. The control condition used the same training device set to function like standard VOR training indistinguishable to the participant. OUTCOMES: After the intervention, ipsilesional VOR function improved substantially. The VOR adapted both via a 52% increase in slow-phase response and via 43% earlier onset compensatory saccades for passive head movements. In addition, the participant reported fewer symptoms and increased participation in sports and daily activities. DISCUSSION: Here, a participant with chronic vestibular hypofunction showing improved oculomotor performance atypical for traditional vestibular rehabilitation therapies, subsequent to using the newly developed IVA technique, is presented. It is the first time to our knowledge an improvement of this magnitude has been demonstrated as well as sustained over an extended period of time.
BACKGROUND AND PURPOSE: Traditional vestibular rehabilitation therapies are effective in reducing vestibular hypofunction symptoms, but changes to the vestibulo-ocular reflex (VOR) are minimal. This controlled case report describes an increase in VOR after 6 months of incremental VOR adaptation (IVA) training in a person with chronic unilateral vestibular hypofunction. CASE DESCRIPTION: The participant was a 58-year-old female with a confirmed (Neurologist P.D.C.) left vestibular lesion stable for 2 years prior to entering a clinical trial examining the effects of daily IVA training. She was evaluated monthly for self-reported symptoms (dizziness handicap inventory), VOR function (video head impulse test), and VOR behavior (Dynamic Visual Acuity test). Intervention consisted of 6 months of 15 minutes per day unassisted training using the IVA training regime with a device developed in our laboratory. The take-home device enables the VOR response to gradually normalize on the ipsilesional side via visual-vestibular mismatch training. The intervention was followed by a 6-month wash-out and 3-month control period. The control condition used the same training device set to function like standard VOR training indistinguishable to the participant. OUTCOMES: After the intervention, ipsilesional VOR function improved substantially. The VOR adapted both via a 52% increase in slow-phase response and via 43% earlier onset compensatory saccades for passive head movements. In addition, the participant reported fewer symptoms and increased participation in sports and daily activities. DISCUSSION: Here, a participant with chronic vestibular hypofunction showing improved oculomotor performance atypical for traditional vestibular rehabilitation therapies, subsequent to using the newly developed IVA technique, is presented. It is the first time to our knowledge an improvement of this magnitude has been demonstrated as well as sustained over an extended period of time.