Identification of Neural Mechanisms in First Single-Sweep Analysis in oVEMPs and Novel Normative Data

Abstract

Background: Bone-conducted (BC) VEMPs provide important tools for measuring otolith function. However, two major drawbacks of this method are encountered in clinical practice—small n10 amplitude and averaging technique. In this study, we present the results of a new VEMP setup measuring technique combined with a novel single-sweep analysis. Methods: The study included BC oVEMP data from 92 participants for the evaluation of normative data using a novel analysis technique. For evaluating test-retest reliability, the intraclass correlation coefficient (ICC) was used. Results: We found significant n10 amplitude differences in single-sweep analyses after the first and second measurements. Thereby, mathematical analyses of the head movement did not show any differences in the first or second measurements. The normative n10 amplitude was 20.66 µV with an asymmetric ratio (AR) of 7%. The new value of late shift difference (LSD) was 0.01 ms. The test retest-reliability showed good to excellent ICC results in 9 out of 10 measurements. Conclusions: Our results support a phenomenon in single-sweep analysis of the first stimuli independent of head movement and signal morphology. Furthermore, the values obtained with the new measurement method appear to be more sensitive and may allow an extended diagnostic range due to the new parameter LSD.

Measurement of Ocular Vestibular Evoked Myogenic Potentials: Nasion Reference Montage as an Alternative to the Clinical Standard Montage

“…Vanspauwen et al compared the ICC for N1 and P1 between the standard electrode montage and a modified belly tendon montage derived from Sandhu et al, revealing higher ICC for the clinical standard (35,36). Even with newly adapted electrode montages or oVEMP stimuli, values of ICC for the clinical standard remained on the level of previous studies while the two newly introduced electrode montages N and L showed higher levels of reliability (15,36,54). Vanspauwen explains the rather low values of ICC for latencies in the context of the ICC's calculation method and the small size of the dataset.…”

“…These results may suggest that, besides statistical reasons and measures for standardization, the use of electrode montage N and L also had a positive impact on reliability. Further optimization of reliability for adults could be achieved in future studies using bone-conducted vibration or new trigger designs as compared by Reddy et al (9,15,33).…”

“…With the help of surface electrodes on the patient's face, it is possible to record the response of the oVEMP reflex pathway in the IO as small excitatory potentials with a latency of 10 milliseconds (N1) and 16 milliseconds (P1) (1,13). Besides latencies, other standard parameters describing the oVEMP reflex pathway include amplitudes (in microvolts) and asymmetry ratio (AR; dimensionless) (3,14,15). These parameters and their alteration, alone or in conjunction with results from complementary methods such as cervical VEMP or video head impulse test, can help assess the function of the equilibrium system and diagnose various disorders of the vestibular organ and beyond (12,(16)(17)(18)(19)(20)(21)(22)(23)(24)(25).…”