Meniere's Disease is commonly diagnosed using Electrocochleography (ECOG). EVestG is a variant of ECOG utilizing one or more patient tilts as stimuli in place of the ECOG's repeated tonal clicks. The dynamic measures averaged 'background-onAA' (onAA=acceleration phase of tilt) and background-onBB (onBB=deceleration phase of tilt) of excitatory (ipsilateral tilt) vestibular responses are compared for a small group of age matched Controls (n=18) and Meniere's Disease patients (n=11). Preliminary data provides for an apparent clearer demarcation between Controls and Meniere's patients. Meniere's patients appear to show not only increased Sp/Ap ratios but also a decreased dynamic range of response as measured by the EVestG response measure averaged 'background-onBB'. Increased sample size is required to validate these findings.

Electrovestibulography (EVestG) is a new diagnostic technique potentially applicable to detecting neurological changes impacting on sensory performance. A complex Morlet wavelet based signal processing technique, a Neural Event Extraction Routine, has been used to extract diagnostically meaningful biomarkers from these EVestG recordings. Separation of Meniere's disease and Benign Paroxysmal Positional Vertigo (BPPV) has been accomplished using a "DC" Biomarker [1]. When using tilt stimuli to evoke a semi circular canal response, otolithic organ responses are also observed. The origin of this "DC" biomarker is likely a multifaceted dipole generated by both semi circular canal and otolithic structures.

A vertical movement stimulus has been applied to 10 healthy subjects in the prone position and recordings of the vestibular responses made using an EVestG configuration. The response encoding has been examined using a novel Neural Event Extraction Routine (NEER) developed to detect otoacoustic field potentials. The potential measures 1. average field potential amplitude and 2. average number of field potentials detected per stimulus phase are examined for suitability as vestibular dynamic performance indices. Average field potential amplitude change produces the larger percentage change during vertical acceleration phases.

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This paper attempts to verify the existence of potentially diagnostically significant periodic signals thought to exist in recordings of neural activity originating from the vestibular nerve, following a single tilt of the head. It then attempts to find the physiological basis of this signal, in particular focusing on the mechanical response of the vestibular system. Simple mechanical models of the semi circular canals having angular velocities applied to them were looked at. A simple single canal model was simulated using CFX software. Finally, a simple model of all three canals with elastic duct walls and a moving cupula was constructed. Pressure waves within the canals were simulated using water hammer or pressure transient theory. In particular, it was investigated whether pressure waves within the utricle following a square pulse angular velocity applied to the canal(s) may be responsible for quasi-periodic oscillatory signals. The simulations showed that there are no pressure waves resonating within the canals following a square pulse angular velocity applied to the canal(s). The results show that the oscillatory signals are most likely not mechanical in origin. It was concluded that further investigation is required.