The effects of hypoxic hypoxia on brain stem mediated stapedial reflex in healthy volunteers.

The stapedial reflex is routinely used both in hearing evaluation and to distinguish cochlear from retrocochlear lesions. The present study was carried out on seven healthy volunteers in the hope of obtaining basic information about the physiological variables of stapedial reflex using hypoxic hypoxia. The results show that a short-term hypoxic hypoxia affects, for the most part, the muscle contraction velocity and the amplitude of the reflex, whereas the latency remains unchanged. This finding indicates that the arterial O2-saturation may have an influence when studying the effects of breathing depressive drugs or in patients with decreased ventilation capacity.