Comparison between thresholds obtained with pure-tone audiometry and the 40-Hz middle latency response

Threshold determinations were performed with the 40-Hz MLR method on 20 individuals of varying age, from one month to adult age. The total number of threshold measurements was 105 in the frequency range from 0.25 to 8.0 kHz. Eighty determinations were performed on persons with hearing loss of 40 dB HL or more and the remaining 25 on normal-hearing persons. One of the investigators estimated the MLR thresholds without any knowledge of the results of the psychoacoustical tests. The MLR thresholds were nevertheless in good concordance with those obtained with behavioural tests. The sensitivity of MLR audiometry for detecting a hearing loss was 100%, and the specificity for recognizing normal hearing was 91%. In 27% of the measurements the thresholds obtained with both methods were identical; in 67% the difference was +/- 15 dB. When the MLR thresholds were estimated by the dependent investigator the corresponding figures were 34 and 74% respectively. When the MLR test was performed on children who were sound a sleep, the MLR thresholds were elevated by about 40 dB.