Pitch discrimination for complex sounds in normal and hearing impaired ears

On the grounds of previous researches on periodicity and virtual pitch, the present paper describes the results of some experiments on pitch extraction in normal ears and in subjects with sensorineural hearing loss of cochlear origin, with harmonic and inharmonic stimuli. The latter stimuli are constituted by complex tones with constant ratios between the frequency of adjacent components; for this reason the term geometric spectrum is used. These stimuli can be considered as an alternative to harmonic stimuli, since inharmonic components play an important role in sound analysis and therefore in the perception of sound. Comparison between the data obtained in experimental measurements from normal and hearing impaired subjects (also in relation to the estimates predicted by a mathematical model for pitch), revealed that pitch extracted by hearing impaired subjects tends to be shifted towards the high frequencies.