Importance of Vestibulo-ocular Reflex Gain and Refixation Saccade Analysis in Individuals with Auditory Neuropathy Spectrum Disorder

The patterns of anti-compensatory saccades of the SHIMP paradigm can differentiate vestibular migraine from healthy individuals

PURPOSE

The aim of the present study was to characterize the HIMP and SHIMP test findings in individuals with vestibular migraine.

METHOD

The study comprised two groups- group I consisted of twenty five adults diagnosed with Vestibular migraine, and group II comprised twenty-five age matched healthy individuals. HIMP & SHIMP were administered using the ICS impulse system for both groups.

RESULTS

Mann-Whitney U test revealed a significant difference (p< 0.05) in VOR gain and VOR suppression gain between the vestibular migraine and healthy individuals. All the subjects in the vestibular migraine group manifested either of the four patterns of anti-compensatory saccades (ACS): (a) bilaterally absent ACS, (b) bilaterally scattered ACS or (c) typical ACS on one side with scattered ACS on the other side (d) unilaterally absent ACS. On the other hand, all the healthy individuals exhibited the presence of an organised ACS bilaterally.

CONCLUSION

VOR pathway is affected in individuals with vestibular migraine. Also, various patterns of ACS are more effective in identifying the subtle vestibular lesion in vestibular migraine. These patterns are useful in differentiating vestibular migraine from healthy individuals.

Video Head Impulse Test: A Comparison and Analysis of Three Recording Systems

The present study aimed to compare the efficacy and reproducibility of three existing systems in a group of healthy individuals for vHIT. A prospective randomized study was conducted on 12 healthy individuals. The vHIT tests were carried out. The values of the gains for the 3SCCs of each ear were collected using the three devices. The expected average gain of 1 was the gain standard. The statistical significance in the difference in gains were assessed. There is good reproducibility of the results of the vHIT examination. EyeSeeCam appeared to be the worst performing system with a slightly overstated average gain of 1.15. Otometrics has longest average examination time per patient. Synapsis is the system with the best quality/time invested and easiest to access. Video head impulse system depends on the examiner's preference, reproducible and superimposable depending on the examiner and experience.