Some observations on the contralateral stapedial reflex artefact

An artefact was observed whilst testing profoundly deaf children with a peters AP61c acoustic impedance meter, using the contralateral stapedial reflex technique at high stimulus levels. A study was carried out on cadavers which confirmed the earlier observation, and this pseudo-reflex was found to be caused by the transmission across the head of the stapedial reflex stimulus tone during contralateral testing. An electronic filter was designed and built which suppressed this artefact. It is suggested that this artefact could be mistaken for a stapedial reflex response.