Combining auditory and visual stimuli in the adaptive testing of speech discrimination

This investigation determined the feasibility of using both auditory and visual stimuli in the adaptive testing of speech discrimination. Thirty-six adults with normal hearing and vision were subjects. Using the adaptive methodology known as the Doublet technique, speech-discrimination testing using monosyllabic word lists from the Northwestern University Auditory Test No. 6 (NU-6) (Tillman and Carhart, 1966) was performed at the target levels of 29.3 and 70.7% for both auditory-only and auditory-visual conditions. The results indicated that a specific discrimination score could be obtained under more adverse listening conditions with the addition of visual cues. The contribution of visual cues was constant for the two target scores. The adaptive technique at the 29.3 and 70.7% targets was reliable for both the auditory-only and auditory-visual conditions. Constant level testing showed good agreement with the adaptive technique for the auditory-visual condition. In conclusion, the use of standard error calculations is useful in determining measurement errors and the effects of an aural rehabilitation program.