| OBJECTIVE:To observe and summarize characteristics of auditory brain stem responses (ABR) evoked by tone bursts and tone bursts in notched noise of two different intensities in otologically normal adults. These three kinds of ABRs were named as follows:tb-ABR, amtb-ABR and bmtb-ABR. To compare the accuracy of tb-ABR, amtb-ABR and bmtb-ABR thresholds in estimating puretone thresholds in otologically normal and sensorineural hearing loss (SNHL) adults, to compare ABRs to tone bursts and to tone bursts ipsilaterally masked by notched noise of different intensities.METHODS:After otoscopic exam, puretone audiometry and tympanometry, tb-ABR, amtb-ABR and bmtb-ABR were recorded in 20 otologically normal adults (totally 40 ears, male/female 10/10) and in 38 SNHL adults (totally 38 ears, male/female 17/21), using the SmartEP auditory evoked potential system. RESULTS:In the otologically normal group, tb-ABR thresholds were 21.6±4.6,14.3±3.1,13.5±4.0,8.0±4.2 dB at 500, 1 000,2 000 and 4 000 Hz, and were 12.8±6.0,6.6±4.9,7.5±4.7,6.8±3.8 dB higher than puretone thresholds respectively. Amtb-ABR thresholds were 20.5±4.9,15.0±2.8, 12.8±3.9,9.1±4.4 dB at 500,1 000,2 000 and 4 000 Hz, and were 11.6±6.0,7.1±4.4, 7.0±4.2,7.1±4.8 dB higher than puretone thresholds respectively. Bmtb-ABR thresholds were 21.3±4.2,14.5±3.5,12.5±3.4,8.8±4.0 dB dB at 500,1 000,2 000 and 4 000 Hz, and were 12.4±5.5,7.4±3.7,6.5±4.1,6.5±4.7 dB higher than puretone thresholds respectively. Tb-ABR, amtb-ABR and bmtb-ABR thresholds at each frequency all approximated each other and there were no statistically significant differences between them. It was the same for difference scores between puretone and tb-ABR, amtb-ABR and bmtb-ABR thresholds. At intensities of 70,50,40 dB nHL, wave V latencies of tb-ABR, amtb-ABR and bmtb-ABR all shortened with the increase of frequency. When the intensity and frequency of tone bursts were the same, the tb-ABR wave V latency was always statistically shorter than amtb-ABR wave V latency. The latter was also always statistically shorter than bmtb-ABR wave V latency. In the sensorineural hearing loss group, the correlation coefficients between puretone and tb-ABR thresholds were 0.91, 0.86,0.92,0.90 at 500,1 000,2 000 and 4 000 Hz, while absolue values of differences between them were 8.8±7.1,8.2±6.4,6.9±5.9,5.3±4.6 dB respectively. The correlation coefficients between puretone and amtb-ABR thresholds were 0.91,0.86,0.92,0.90 at 500,1 000,2 000 and 4 000 Hz, while absolue values of differences between them were 8.8±7.1,8.2±6.4,6.9±5.9,5.3±4.6 dB respectively. The correlation coefficients between puretone and bmtb-ABR thresholds were 0.91,0.86,0.91,0.89 at 500,1 000,2 000 and 4 000 Hz, while absolue values of differences between them were 8.9±7.1,7.7±7.1, 5.7±5.0,4.9±5.3 dB respectively. The mean absolue values of differences between puretone thresholds and thresholds for three ABRs had no statistically differences.CONCLUSIONS:Thresholds for ABRs to tone bursts and tone bursts ipsilaterally masked by notched noise were useful in predicting puretone thresholds. If the sensorineural hearing loss were so severe that tone bursts ABR thresholds were more than 40 dB nHL, masking tone bursts with ipsilateral notched noise could improve the frequency specificity of responses.OBJECTIVE:To compare auditory steady-state responses (ASSR) thresholds recorded in both bilaterally multiple-stimulus and unilaterally single-stimulus conditions in otologically normal adults, to compare the correlations between puretone thresholds and ASSR thresholds in both conditions in otologically normal adults. To investigate the correlations between puretone and multiple auditory steady-state response (MASTER) thresholds in sensorineural hearing loss (SNHL) adults. METHODS:After otoscopic exam, puretone audiometry and tympanometry,30 otologically normal adults (totally 60 ears, male/female 14/16) underwent ASSR in bilaterally multiple-stimulus and unilaterally single-stimulus conditions, while 34 SNHL adults (totally 48 ears, male/female 14/20) underwent MASTER. RESULTS:In the otologically normal group, ASSR thresholds in bilaterally multiple-stimulus condition were 57.3±12.4,48.6±10.7, 47.2±9.6,49.5±9.6 dB peSPL at 500,1 000,2 000 and 4 000 Hz. These were 36.0±12.5, 30.0±10.7,26.5±9.5,29.7±9.4 dB nHL, and were 27.9±12.0,23.2±10.0,20.7±7.9, 25.8±10.1 dB higher than puretone thresholds respectively. ASSR thresholds recorded in unilaterally multiple-stimulus condition were 38.8±10.9,27.0±6.0,30.2±5.5, 34.0±8.4 dB peSPL at 500,1 000,2 000 and 4 000 Hz. These were 17.6±10.7,8.4±6.0, 9.5±5.4,14.4±8.5 dB nHL, and were 11.1±8.0,5.6±5.2,5.9±5.0,10.5±7.4 dB higher than puretone thresholds respectively. ASSR thresholds in bilaterally multiple-stimulus condition were 15.5±12.1,22.6±10.3,18.3±7.1,16.1±8.6 dB higher than those of unilaterally single-stimulus conditions at 500,1 000,2 000 and 4 000 Hz. The results indicated significantly statiscical differences. The difference scores between puretone and ASSR thresholds in bilaterally multiple-stimulus condition were also statistically higher than those of the unilaterally single-stimulus condition. The correlation coefficients between puretone thresholds and ASSR thresholds in bilaterally multiple-stimulus condition were-0.188,-0.167,0.303,0.170 at 500,1 000,2 000 and 4 000 Hz. The correlation coefficients between puretone thresholds and ASSR thresholds in unilaterally single-stimulus condition were-0.029,-0.126,0.100,0.382 respectively. In the sensorineural hearing loss group, absolute values of differences between puretone and MASTER thresholds were 17.4±10.9,13.4±6.8,13.1±6.2,16.3±9.5 dB at 500,1 000, 2 000 and 4 000 Hz, and the correlation coefficients between these two kind of thresholds were 0.77,0.89,0.86,0.72 respectively. Mean absolute values of differences between puretone and MASTER thresholds at each frequency were statistically lower than those of the otologically normal group. CONCLUSIONS:ASSR thresholds neither in bilaterally multiple-stimulus condition nor in unilaterally single-stimulus condition could accurately predict puretone thresholds of adults with normal hearing. MASTER thresholds were useful in predicting puretone thresholds of adults with sensorineural hearing loss. OBJECTIVE:To compare auditory steady-state responses (ASSR) thresholds with those of auditory brain stem responses (ABRs) evoked by tone bursts and tone bursts in notched noise of two different intensities in otologically normal adults. These three kinds of ABRs were named as follows:tb-ABR, amtb-ABR and bmtb-ABR. To compare the accuracy of predicting behavioral thresholds using ASSR and ABRs thresholds in otologically normal and sensorineural hearing loss (SNHL) adults. METHODS:Totally 30 otologically normal adults (60 ears, male/female 14/16) and 34 SNHL adults (48 ears, male/female 14/20) underwent a series of otoscopic exam, puretone audiometry, tympanometry, ASSR, tb-ABR, amtb-ABR and bmtb-ABR. All the otologically normal and SNHL adults underwent multiple auditory steady-state response (MASTER). Eight otologically normal adults (16 ears) also underwent ASSR in unilaterally single-stimulus condition. RESULTS:In the otologically normal group, not only ASSR thresholds at each frequency in bilaterally multiple-stimulus condition, but also the difference scores between ASSR and puretone thresholds were statistically higher than those of tb-ABR., amtb-ABR and bmtb-ABR. The standard deviations of difference scores between ASSR and puretone thresholds were also higher than those of ABRs. Data of ASSR in unilaterally single-stimulus condition came from 15 otologically normal adults (30 ears) of the second part. The results suggested statistical differences between ASSR and ABRs thresholds, while difference scores between evoked potential and puretone thresholds were near the same. But the standard deviations of difference scores between ASSR and puretone thresholds were higher than those of ABRs. In the SNHL group, the absolute values of differencs between MASTER and puretone thresholds at each frequency were all statistically higher than those of tb-ABR, amtb-ABR, and bmtb-ABR. It was the same for the standard deviations of the absolute values of differences. CONCLUSIONS: When predicting puretone theresholds in a population where the incidence of normal hearing is expected to be high, tb-ABR., amtb-ABR and bmtb-ABR might be more appropriate choices than ASSR recored both in bilaterally multiple-stimulus and unilaterally single-stimulus conditions. MASTER were less accurate than tb-ABR, amtb-ABR and bmtb-ABR in predicting puretone thresholds across all the SNHL adults.OBJECTIVE:To study the relationship between puretone behavioral thresholds and auditory brain stem response (ABR) thresholds to tone bursts and tone bursts ipsilaterally masked by notched noise in infants and children. These three kinds of ABRs were named as follows:tb-ABR, amtb-ABR and bmtb-ABR. To study the relationship between puretone behavioral thresholds and thresholds for 40Hz Auditory Events Related Potentials (40 Hz AERP). To evaluate the accuracy of tb-ABR, amtb-ABR and bmtb-ABR thresholds in estimating puretone behavioral thresholds of infants and children. METHODS:Totally 12 infants and children (16 ears, male/female 5/6), who aged from 8 months to 6 years, underwent a series of tb-ABR, amtb-ABR, bmtb-ABR, 40 Hz AERP and puretone behavioral audiometry. RESULTS:In these infants and children, absolute values of differences between tb-ABR and puretone behavioral thresholds were 9.2±6.7,9.9±7.5,11.8±6.8,8.8±4.0 dB at 500,1 000,2 000 and 4 000 Hz, while absolute values of differences between real puretone behavioral thresholds and puretone thresholds predicted by tb-ABR were 14.1±9.5,11.5±9.3, 12.5±6.8,6.5±4.2 dB respectively. Absolute values of differences between amtb-ABR and puretone behavioral thresholds were7.7±6.1,8.3±7.5,9.4±5.0,7.5±3.8 dB at 500, 1 000,2 000 and 4 000 Hz, while absolute values of differences between real puretone behavioral thresholds and puretone thresholds predicted by amtb-ABR were 11.6±8.9, 8.8±6.2,6.8±4.0,6.0±4.6 dB respectively. Absolute values of differences between bmtb-ABR and puretone behavioral thresholds were 8.0±5.4,7.2±5.7,8.3±6.1, 8.8±3.5 dB at 500,1 000,2 000 and 4 000 Hz, while absolute values of differences between real puretone behavioral thresholds and puretone thresholds predicted by amtb-ABR were 8.5±5.7,8.1±5.3,7.6±5.,8.4±3.5 dB respectively. Absolute values of differences between 40 Hz AERP and puretone behavioral thresholds were 13.5±7.5, 20.5±8.6,22.6±8.6,16.0±7.6 dB at 500,1 000,2 000 and 4 000 Hz. Absolute values of differences between 40 Hz AERP and puretone behavioral thresholds at each frequency were statistically higher than those of tb-ABR, amtb-ABR and bmtb-ABR. It was the same for the standard deviations of absolute values of differences. CONCLUSIONS: Thresholds for ABRs to tone bursts and tone bursts ipsilaterally masked by notched noise were useful in predicting puretone behavioral thresholds of infants and children. Masking tone bursts by ipsilateral notched noise could improve the prediction. When predicting puretone behavioral theresholds of infants and children using auditory evoked potential thresholds, ABRs to tone bursts and tone bursts ipsilaterally masked by notched noise could be more accurate than 40 Hz AERP.
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