[Dynamic properties of the ipsilateral tactile-elicited stapedius muscle reflex in probands with normal hearing]

We tested 94 male and female persons with normal hearing. From these persons we elicited from the external ear canal the ipsilateral tactile stapedius muscle reflex and examined its dynamic properties. The electric stimulus consisted of a series of electric impulses of a duration of 30 msec lasting for 1 sec. The intensity ranged from 2.0-8.0 mA increasing in steps of 0.5 mA. Statistical evaluation showed a significant reflex dependence on stimulus intensity and sex of the volunteers but not on the volunteer's age. Starting with a stimulus intensity of 3.5 mA all tested persons showed good reflex response. The average latency between the start of the stimulus and the beginning of the reflex was 130-200 msec diminishing with growing stimulus intensity. The best parameters describing the dynamic properties of the reflex seem to be the latencies L 1 and L 3 at a stimulus intensity of 3.5 - 6.0 mA.