[R01] Exploration of off-axis effects following VOR adaptation

Ente: National Institute on Deafness and Other Communication Disorders

Scadenza: 2031-05-31

Importo max: 371.422 EUR

Paese: US

Descrizione

The current clinical approach to treating dizziness/vertigo from vestibular disease is based primarily on addressing problems within the gaze stability pathway, specifically targeting the rotational vestibulo-ocular reflex (VOR). Despite evidence of both isolated otolith and combined canal-otolith disorders, no rehabilitation exercises specifically target otolith disorders. Balance is thought to be mediated primarily by otoliths, yet surprisingly individuals with isolated semicircular canal deficits (gaze stability pathway) also experience imbalance. It is unclear how changes in rotational VOR pathways, like after vestibular neuritis, lead to dysfunctional effects in non-gaze stability pathways such as balance ability. Semicircular canals (SCC) and otolith pathways are known to converge, resolving head-tilt and facilitating head on body orientation in SCC specific planes. However, a mechanism linking reduced VOR gain to adverse postural effects remains unknown, leaving this potential adverse reaction to gaze stabilization exercises treatment unaddressed. Off-axis neural adaptation or increased vestibular sensory noise (variability) rather than reduced VOR gain may account for the increased sway for individuals with balance problems. We will compare two methods of VOR adaptation techniques (peripheral desensitization versus cerebellar learning) to probe off-axis bias shifts and sensory process noise for both isolated and integrated semicircular canal and otolith responses, expanding current understanding of the neural pathways influenced by VOR (gaze stability) adaptation. Vestibular reflex behavior within the vestibulospinal pathways is known to demonstrate context specificity, meaning that vestibulospinal reflexes are only measureable in leg muscles during standing. It is unclear whether postural context (sitting versus standing) or somatosensory reliability impact any off-axis postural effects caused by gaze stability exercises. Additionally, conflicting theories may explain off-axis postural effects after performing gaze stability exercises including systematic change in vestibulospinal signals, increased variability in vestibulospinal signals, or modifications to central processing of vestibular signals for balance. Determining context and postural dependent effects will immediatly impact safe exercise design. Dr. Anson and his team will conduct a series of studies to answer these important questions. They will determine whether horizontal VOR adaptation leads to off-axis reflex modulation in untrained neural pathways (Aim 1). They will determine whether training context modifies the magnitude or recovery trajectory for postural sway after VOR adaptation (Aim 2). They will also compare the effect of VOR adaptation on sensory weighting and vestibulospinal sensory noise (Aim 3). This proposal examines the mechanisms of unintended sway increase after gaze stabilization exercises, addressing exercise-induced fall risk for individuals with dizz Istituzione: UNIVERSITY OF ROCHESTER PI: Eric Richard Anson Progetto: 1R01DC022854-01A1

Settori: National Institute on Deafness and Other Communication Disorders

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