Analysis of possible interactions of an attentional task with cochlear micromechanics.

Several contradictory studies have been published regarding the effect of selective attention on cochlear mechanics, possibly modulated through efferent pathways. Click-evoked otoacoustic emissions have been proposed as a highly sensitive tool for testing the hypothesis of such a modulation. In this study, two other types of evoked otoacoustic emissions (i.e. distortion products and stimulus frequency emissions between 1 and 4 kHz) were measured on 20 normal subjects in absence and presence of a visual selective attention task. The duration of measurements at a given frequency was short enough to eliminate possible artefacts due to long-time averaging. No significant change was observed in these signals, considered as probes of cochlear micromechanics. It is concluded that in this set of experimental conditions, selective attention has a negligible effect on peripheral sensitivity.