The relative importance of recovery time in compression hearing aids

Recovery time (RT) in compression hearing aids was studied using six aids of identical characteristics except for factory-modified RT. Recordings of CID W-22 lists were made through the aids and played to normally hearing and otopathologic (sensorineural) subjects. Speech intelligibility was measurably influenced by RT variation with attack time held constant (10 ms). The effect was much more pronounced with the normal than with the hearing-impaired listeners, a phenomenon not unexpected when testing such a subtle feature in a low-fidelity transmission system. When the RTs of the aids were respecified according to a proposed standard (IEC) the data suggested that RTs for English in the vicinity of 90 ms may be most desirable. Additional work is required using more complex stimuli and background noise.