Introduction:
It is not clear yet to what extent the clinical acceptance of oVEMP-examinations depends on methodological aspects.
Methods:
In 60 subjects, twelve different oVEMP-settings were studied in a randomized order: air conducted sound (AC) and bone conducted vibration (BC), stimulation at 500 and 1000 Hz, three electrode positions (standard (1), standard + nose reference (2), belly-tendon + nose reference (3)). The upgaze angle was measured by means of a small laser pointer mounted on the head of the patient. After each investigation, the patient's comfort and effort was determined using a visual analogue scale (Comfort: 0 = comfortable, 10 = uncomfortable; Effort: 0 = easy, 10 = exhausting).
Results:
The difference in comfort was 5,54 ± 1,98 (AC) versus 4,85 ± 2,21 (BC). The difference in effort was 5,29 ± 2,35 versus 4,93 ± 2,58. Only the difference in comfort was significant (p = 0,024). The comfort of Pos.3 (2,49 ± 1,73) showed a significant difference (p < 0,001) compared to Pos.1 (4,78 ± 2,00) and Pos. 2 (4,84 ± 2,24). There was no significant correlation between maximum upgaze angle and effort for AC, BC or the combination of both (AC and BC). The willingness to tolerate a second oVEMP measurement was equally high for AC and BC (AC and BC: 95%, BC: 96,7%, AC: 93,3%).
Conclusion:
BC is significantly more comfortable than AC, and Pos.3 (“belly tendon”) is preferred to Pos. 1 and 2. This suggests the use of this combination in routine clinical investigations, for the patient's sake. As to the compliance in an oVEMP measurement, it should be taken into account that the patient's effort and the maximum upgaze angle are uncorrelated.
