| The relationship between deficits in musical pitch recognition and auditory processing abilities in individuals age 15 - 60 was examined. Thirty-five (35) tune deaf adults were identified by screening a large random population using The Distorted Tunes Test (DTT). Thirty-four (34) normal controls, matched for age, gender, education, and hearing status were included as a normal control group for comparison. This investigation consisted of two phases. During Phase 1, 864 medically normal individuals were screened at random to identify those who scored poorly on the DTT, a measure of musical pitch recognition ability. These individuals were given a full audiologic examination, and those with hearing loss or other confounding audiologic factors were excluded from further testing. Sixty-nine participants who qualified in Phase 1 volunteered to take part in Phase 2, which consisted of a series of auditory and temporal processing tests. Tests included an adaptive difference limen frequency test, pitch and duration pattern recognition tests, and a temporal resolution test. Additionally, a battery of phonological processing tests was administered to assess the subjects' abilities to manipulate, discriminate, and segment speech sounds. Fourteen (14) different tests of phonological processing were administered to these two groups. Additionally, tests of short-term and long-term memory were administered. Results show no difference between tune-deaf individuals and normal controls in auditory short-term memory and visual long-term memory. However, tune deaf participants as a group displayed poorer frequency discrimination for pure tones, poorer auditory pattern discrimination, and gap detection. A significant difference was found between the groups in phonological awareness, (the ability to discriminate and manipulate phonemes in syllables and words), and phonemic awareness (the ability to segment words into individual phonemes, count individual segments in words or sentences, and manipulate phonemic segments in words). Notably, a fraction of tune-deaf individuals demonstrated normal abilities on one or two of the following measures: (a) frequency discrimination for pure tones, (b) pattern discrimination, or (c) phonological processing. Findings indicate that tune deafness is a heterogenous condition, and that some cases of this disorder are not associated with deficits in pure tone frequency discrimination. They also indicate that deficits in musical pitch perception frequently co-exist with deficits in phonological and speech sound processing. This supports the view that the neural structures and functions that are used in the auditory perception of music are also used in perception of speech. |
