The influence of systemic circulation on hearing: The reliability of a different impact of microcirculatory defects and atherosclerosis.

The extension of the dependence of hearing acuity from circulatory factors has been widely evaluated in the literature, without reaching an univocal conclusion. In our opinion, a precise distinction between acute/fluctuating disorders and progressive hearing loss must be made in order to identify the possible circulatory causes. Actually, it is conceivable to hypothesize that an acute lack of perfusion plays a major role in the inner ear microcirculation, and may be responsible for acute hearing damages; on the other hand, systemic atherosclerosis may coexist with good hearing provided that a sufficient local perfusion is maintained. This distinction, supported by our findings over the year, appears logical considering the autoregulatory properties of the cochlea and the differences between large/middle vessels and microvasculature; moreover, it can explain the finding of both people with no cardiovascular risk factors and (usually) unilateral inner ear affections and people with diffuse atherosclerosis and well preserved hearing, not exceptionally occurring in daily practice.