Audiometric Thresholds Estimated By Multiple Auditory Steady-state Responses To Air And Bone Stimuli

Part 1 Application of Bayes discriminatory analysis and linear regressionequation predicting behavioral thresholds using AC-ASSR testObjective :(1)To study the accuracy of air condition multiple auditorysteady-state responses(AC-ASSR) for estimating behavior hearingthresholds. (2)To build a mechanism model for the classification of hearingloss by Bayes discriminatory analysis and predict behavioral thresholds bylinear regression equation.Methods:Normal adults and patients of different degree sensorineuralhearing loss were tested by AC-ASSR and AC-PTA respectively. A mechanismmodel was built for the classification of hearing loss by Bayes discriminatoryanalysis by different frequency and different hearing group ASSR thresholdanalysis. Linear regression equation was built by thresholds of AC-ASSR andAC-PTA of different frequencies, different hearing group.Result: The BC-ASSR thresholds and BC-PTA thresholds with Pearsoncorrelation coefficients were between 0.7 and 0.94. The accurate rate ofdiagnostic model was 91.5% of original grouped cases classified and 90.5%of cross validated grouped cases classified.Conclusion: AC-ASSR was proven to be a valid technique for estimation ofan objective audiogram. Bayes discriminatory analysis could be useful inclassification of hearing loss. Linear regression equation could be usefulin predicting behavioral thresholds. Part 2 Multiple auditory steady-state response thresholds tobone-conduction stimuli in young adults with normal hearing and adults withmild sensorineural hearing lossObjective: To investigate the clinical usefulness of multiple auditorysteady-state response thresholds to bone-conduction stimuli in young adultswith normal hearing and adults with mild sensorineural hearing loss.Methods: ASSR thresholds to bone conduction stimuli(carrierfrequencies:500Hz to 400Hz;77 Hz to 101Hz modulation rates;ampltitude/frequency modulated; alternate polarity stimulus)were tested in 30 normalhearing young adults and 20 mild sensorineural hearing loss. The responsethresholds were compared with pure tone audiometry for bone conduction stimulithresholds.Result: In normal young adults the thresholds for BC-ASSR at500, 1000,2000,4000Hz were 68.08±5.83, 59.92±6.86, 57.08±8.60, 61.83±8.63dB SPL, respectively and 16.25±4.94, 11.58±5.48, 15.67±6.74, 15.75±5.86dBHL above pure tone thresholds for bone conduction stimuli. The BC-ASSRthresholds and BC-PTA thresholds with Pearson correlation coefficients were0.67,0.61,0.62,0.71 at 500, 1000,2000,4000Hz respectively. The similar resultswere observed in the audlts with mild sensorineural hearing loss.Conclusion: The study shows that multiple auditory steady state responsesto bone bone-conduction technique is useful method in estimating of hearingthreshold of young adults with normal hearing and adults with mildsensorineural hearing loss. Part 3 Bone conduction multiple auditory steady-stateresponse:investigations into Artifact responsesObjective:To investigate the characteristic and clinical application ofartifact of bone conduction multiple auditory steady state response.Methods: 80 deaf-mute children examined by a series of traditionalcomprehensive test battery proved to be severe-to-profound sensorineuralhearing losses(SNHL). This group children could not heard the BC-ASSRs stimuliwith the intensity varied from 50 to 100dB SPL and if only the response appearedduring the test, that is a spurious response.Result: The false positive rate significantly increased at high-intensityBC ASSR stimuli. Because all subjects were bilateral severe-to-profoundSNHL, it was reasonable to conclude that the BC-ASSRs were not generated bythe auditory system.Conclusions: An artifact may be present in the recording of BC-ASSR at highlevels. Upper limits of BC-ASSR may be determined 80,90,90dB SPL at500,1000,2000Hz respectively.