MONAURAL VERSUS BINAURAL DISCRIMINATION FOR FILTERED CNC MATERIALS: THE IMPAIRED AUDITORY MECHANISM.
Rept. for 1 May 63-15 Dec 64,
NORTHWESTERN UNIV EVANSTON ILL AUDITORY RESEARCH LAB
Pagination or Media Count:
Northwestern University Auditory Test No. 4 was altered by 1 low-pass filtering with a 1480 cps cutoff frequency and a 54 dB per octave slope and 2 high-pass filtering utilizing an 1830 cps cutoff frequency and a 36 dB per octave slope. By using these filtered materials, a single binaural and two monaural articulation functions were derived for each of 60 subjects with peripheral hearing losses and 7 subjects with unilateral CNS lesions judged to involve the auditory system. In the monaural conditions each subject received either the high-pass or low-pass filtered signal. In the binaural condition the two messages were presented simultaneously, one to each ear. The experimental hypothesis predicted that for the subjects with peripheral impairments, the slope of the binaural function would exceed that of the steeper monaural one. Conversely, it predicted that for the subjects with unilateral central involvement, the binaural function would not differ in slope from the monaural functions. Results only partially confirmed this hypothesis. For both groups, the slope of the binaural function exceeded that of the steeper monaural function however, the slope of the binaural function for the peripheral lesion group exceeded that of the CNS lesion group. Since the hearing acuity of the latter group was within normal limits, this fxinding indicates that in unilateral central auditory lesions, the binaural processing of speech signals is incomplete. Author
- Medicine and Medical Research