Perceptual Considerations in Designing and Fitting Hearing Aids

The opportunities for masking in music abound, and compared with speech, the range of pitch and intensity levels can vary dramatically. Musical tones include important energy components infringing on both the lower and upper pitch limit. For example, the fundamental frequency of low piano tones fall below 20 Hz, and the upper partials of violin tones rise above 20,000 Hz. In addition, the difference between peak intensity and average intensity is considerably higher in music than it is in speech. 1,2 This additional variability amounts to a formidable challenge for any auditory system—let alone one that is impaired in some manner. Fortunately, however, the affective experience of music does not depend on veridical perception of any one dimension, and is heavily influenced by long-term memory and schemas. For example, a particularly important pitch can be indicated by an increase in loudness, vibrato, and duration, as well as expectancy generated by the sequence of preceding pitches. In addition, affective aspects of music tend to be overdetermined with convergent cues from multiple dimensions. Thus, reduced sensitivity to a particular dimension of music will not necessarily lead to a gross distortion in music perception, and will almost never lead to a music experience devoid of affective possibilities. Indeed it is uncommon for people with acquired hearing loss to turn off music completely.