Digital processing of speech materials in the study of sensorineural hearing impairment

Existing literature suggests that the hearing mechanism deals with incoming speech material by filtering the signals into a series of frequency bands. The width of these bands has been referred to as the critical band and is a perceptual frequency bandwidth that is observed in a variety of psychoacoustic contexts. Researchers at the Environmental Acoustics Laboratory of The Pennsylvania State University have developed digital processing techniques for altering available recorded speech materials so that the frequency resolution available in the resultant materials may be controlled. Tapes have been produced wherein the frequency bandwidth resolution is limited to no better than one critical band and these tapes have been used in intelligibility testing. Some existing research indicates that the critical band is considerably widened in the individual with sensorineural hearing loss of cochlear etiology. The digital processing routines described above were also used in developing tape recorded materials wit...