The generic term 'sudden hearing loss' indicates the lack of knowledge about the etiology and pathogenesis of this phenomenon. In most cases it would seem feasible to consider infections or organic circulatory defects, but there are cases, generally affecting young subjects in whom the damage is often reversible, in which a functional origin is possible. We therefore investigated the possible effect of systemic arterial pressure in a retrospective study in a group of 36 patients aged not more than 40 years, treated for sudden hearing loss, comparing the mean values of their arterial pressure with those of a control group of 25 subjects, of similar age, admitted for other disorders. The significantly lower mean values of arterial pressure in the group affected by sudden hearing loss and the easier reversibility of the damage in these patients suggests that, at least in some cases, the cochlear damage may be caused by a perfusion deficit due to the combined effect of hypotension and imperfect vasomotor regulation.