Acoustic reflex in patients with cochlear implants (analog stimulation)

Stapedius reflexes were tested in 21 deaf patients with the Vienna cochlear implant using intra- or extracochlear electrodes. Sinusoidal bursts of 125, 500, 1,000 and 2,000 Hz were used as stimuli presented in a randomized sequence. The contralateral acoustic reflex was monitored by synchronized sampling of the acoustic impedance of the ear. Results obtained were compared to psychoacoustic sensation values. The reflex threshold always was located close to the uncomfortable loudness level within the subjective dynamic range, or at least above the most comfortable loudness level. Practical applications of reflex testing and limitations of the method for use in children are discussed.