Ipsilateral acoustic reflex detection using wideband acoustic reflectance, admittance, and power measurements

Abstract

Progress has been achieved in measuring contralateral acoustic reflex shifts to tonal and noise activators in wideband reflectance, admittance, and power [Feeney and Keefe, J. Speech, Language, and Hearing Research (in press)], but no measurements have been made of the corresponding ipsilateral reflex shifts. Because the thresholds of these wideband contralateral reflex shifts were at least 8 dB lower than those obtained using standard clinical techniques, and because clinical research requires the use of both contralateral and ipsilateral testing, it is of interest to formulate a wideband technique to measure the ipsilateral reflex. Such an ipsilateral technique has been developed based on the observation that the major component of the contralateral reflex is below 1.6 kHz. Probe signals were designed with bandwidths from 0.25 kHz up to 1.6 or 2 kHz, and calibrated to measure reflectance (and related responses). The reflex activator signals consisted of tonal stimuli in the range from 2–4 kHz, with levels varied to measure reflex input–output functions. Ipsilateral reflex shifts have been detected using this technique. Work is in progress to compare ipsilateral and contralateral reflexes measured using the same probe and activator signals. [Work supported by NIDCD.]