Psychometric functions for the CID W-22 and NU Auditory Test No. 6. Materials spoken by the same speaker

The equivalence was determined for the W-22 and NU No. 6 lists recorded with the same carrier phrase and by the same speaker (Auditec compact disc). For presentation, the lists were interleaved to form lists of 100 words. In Experiment 1, the materials were presented in quiet (0 to 30 dB HL) and in 60 dB SPL speech-spectrum noise (35 to 65 dB HL) at 5 dB intervals to 24 subjects with normal hearing. In Experiment 2, the materials were presented at two levels 10 dB apart to 24 subjects with sensorineural hearing loss. Recognition performance was on average 4 to 8% better on NU No. 6 materials than on the W-22 materials, a difference that was significant for both subject groups. The 2 to 4 dB differences are within the 5 dB steps typically used clinically and are not considered of clinical significance.