Several epidemiological studies highlighted a synergistic interaction between noise and mechanical vibration exposure.1 The etiologic mechanism is still missing. Moreover, the measured transmissibility from the hand to the head seems to be poor. At the shoulder, frequency over 30 Hz are practically suppressed. If there are not any vibration left, how can mechanical energy interact with the cochlea? The aim of this speculation is to approach the transmission of vibration from entering point to the cochlea from a different point of view.Proposed methods
In the seminar on hand-arm vibration exposure3 to isolated and repeated shock vibrations held in October 2015 in Beijing it was suggested that a wider spectral component of mechanical vibration may travel in the blood vessels and impair vasoregulation and nerve terminations in fingers. Such a suggestion may apply to transmission to even more far district, due to the fact that blood vessels can work as waveguide for pressure, because they are designed to be so.Methodology
Can be summarised as following. Effects of vibrations on the hearing function will be assessed by stimulated otoacoustic emission method. Vibration elicitation will be strictly controlled (shaker and 6 DOF vibrating plate). Overall vibration will be measured by accelerometers on joints and head. Blood vessel vibration propagation will be measured by high resolution, dual frequency echography4,5 on main vessels (coronary) and small vessels. The frequency spectrum of hearing loss and blood vessels vibrations, deducted by the heart pumping effects, will be compared to look for coincidence.