Hearing loss: listening in the dips

Hearing loss is normally considered to be a reduction of auditory sensitivity requiring treatment by amplification using hearing aids. However, many patients find amplification to be unsatisfactory, complaining of too much loudness and a ‘lack of clarity’. I will argue, using computer modelling studies of auditory brain physiology, that peak amplitude may be less relevant to hearing loss than reduced sensitivity to brief silences or ‘dips’ in the speech waveform. Dips help to define words and dips in background babble make listening to speech possible in noisy situations (the ‘cocktail party problem’). Hearing loss may make the dips less obvious and less useful. ‘Dip listening’ problems may be a consequence of a failure of auditory ‘efferent’ function caused by reduced number of functioning cochlear outer hair cells. The brain’s efferent system (top-down) has always been something of a mystery to psychologists but its suppressive effects, in hearing at least, might be contributing ‘clarity’ to our auditory perceptual experience.