Dichotic listening to speech: VA-CD data from elderly subjects.

The Department of Veterans Affairs (VA) compact disc (VA-CD) Tonal and Speech Materials for Auditory Perceptual Assessment, Disc 1.0 contains three dichotic speech tests. Two of them, namely, dichotic digits and dichotic synthetic sentences, are tasks that are easily and accurately performed by young normal listeners. The third test, dichotic nonsense syllables, is a more difficult task for normal listeners to perform well. Few data have been gathered from use of the VA-CD with subjects other than young adults with normal hearing sensitivity. This account is about 19 elderly patients with hearing loss in a VA long-term care facility and how they performed on the trio of dichotic tasks on the disc. The digits, sentences, and syllables were presented at 80 dB SPL in a dichotic format requiring two responses to each trial. Trials using syllables were also done at 90 dB SPL to quantify the effects of hearing loss. Digits were recognized better than sentences; both were recognized better than syllables, and this was true for both ears. Compared to results from young listeners, correct responsiveness for older people was most reduced on the syllable task, but performance on dichotic sentences was also reduced. The results corroborate previous reports that suggest that many aging auditory systems do not process dichotic nonsense syllables as well as younger ones. The results also suggest that the dichotic procedures on the VA-CD provide a useful continuum of difficulty for the clinician and investigator.