PP1507 - VOR and vHIT Outcomes in Dancers and Non-Dancers

Abstract: Dance training may be a viable option for vestibular rehabilitation and fall prevention. The purpose of the current study was to explore the training-related plasticity effects on the vestibular system performance of dancers. VOR and vHIT were measured in 26 participants with and without dance training. Results showed significant effects for HIMP and VVOR gain across dancers and non-dancers but no significant effects for SHIMP. The results of the current study provide substantial evidence that dance training techniques may be utilized to improve the functional balance of individuals of all ages.

Summary: Dance training involves the visual, somatosensory, and vestibular systems, and may be a viable option for vestibular rehabilitation and fall prevention. The function of the VOR is to produce an eye movement that compensates for head movement, and therefore under near-perfect conditions, the portion of the response that the vestibular system contributes to should be a mirror image of head velocity, thus producing a gain value close to 1.0 (Shepard & Jacobson, 2016b). Dancers utilize vestibular plasticity to complete multiple rotations in a pirouette without perceiving any sense of dizziness. The skill dancers utilize to achieve this is known as “spotting.” Spotting involves having the dancer find a target to look at while preparing for the pirouette and holding their focus on the target while completing whole-body rotations. The underlying physiological basis for vestibular rehabilitation therapy (VRT) is the plasticity of the central nervous system (Gans, 2015). The purpose of the current study was to explore any such plasticity effects in dancers with extensive training. 
13 dancers and 13 non-dancers were included in the present study. Dancers had to have at least five years of classical dance training, be able to complete a double pirouette, and be able to complete fouetté/a la seconde turns. vHIT testing was conducted using the Otometrics ICS Impulse vHIT System. All the participants underwent the HIMP test of the horizontal semicircular canals followed by the SHIMP test of the horizontal semicircular canals. The instantaneous gain was retrieved for each participant calculating the ratio of the eye velocity to the head velocity for the right and left. The average VOR gain was calculated after 15 valid impulses were obtained for each of the horizontal semicircular canals. Participants were asked to complete standing whole-body rotations (spins) for eight full rotations. VVOR average gain was measured by calculating the average eye movements divided by the average head movements for three whole-body rotations.
The data was analyzed using multivariate analysis of variance (MANOVA) on SPSS software for HIMP and SHIMP gain. MANOVA results showed significant effects for HIMP (F {1,50} = 4.82; p = 0.03) but no significant effects for SHIMP (F {1,50} = 1.08; p= 0.30). For VVOR average gain, data was analyzed using a univariate analysis of variance (ANOVA) on SPSS software.  ANOVA results showed significant effects for VVOR gain (F {1,24} = 26.51; p = < 0.001). 
The results of our study indicate the ability of the human vestibular system to rewire itself over time when provided intensive and repetitive training. Vestibular plasticity is not a new concept and evidence of this is present in patients who go through extensive vestibular rehabilitation therapy (VRT). By nature of their training, dancers incorporate gaze stabilization techniques to be able to complete multiple rotations during pirouettes while being able to fixate on an imaginary target and keep their focus clear on the fixed target during whole-body rotations. The results of the current study provide substantial evidence that dance techniques may be utilized to improve the functional balance of individuals of all ages (Filar-Mierzwa et al., 2015).