Comparison of two VHIT software programs in diagnostics of semicircular canals

The aim of this work was to assess SCC function in VHIT test, using both versions of VHIT ULMER.

The study was performed in 57 subjects aged 22-33 years (48 women and 9 men) without vertigo in anamnesis. Patients did not complain of any "vertigo" ailments or any balance disorder incidents in the past. All tests using either VHIT I or VHIT II were performed by the same person. The function of lateral SCC in VHIT ULMER II was examined similarly like in VHIT ULMER I. In both methods was used the same sensitivity threshold parameters for horizontal and vertical accelerations (horizontal - 2500, vertical - 1600). Each of these sequences enables a parameter, called represented GAIN, to be calculated in form of a point on the canalogram.

GAIN represents the deviation of the gaze in comparison to the deviation of the head between the first (t - 0 ms) and the fourth image (t = 120 ms). The calculation formula is: GAIN (in %) =100 x DG/RH. DG is deviation of the gaze ("gaze velocity in space") and RH is rotation of the head ("head velocity or impulse canal paresis"). Normal GAIN value ranges 1-40%.

The examination using VHIT ULMER II appears to be a more sensitive diagnostic method than VHIT ULMER I. Improved software with automated functions such as camera adjustments, examination surface arrangement, of VHIT ULMER II, enables technician to shorten the time of examination, simultaneously providing a range of new information about the condition of oculo-vestibular system.