BACKGROUND AND OBJECTIVES: The aim of this study was to analyze the summating potential (SP)/action potential (AP) ratio of electrocochleography (ECoG) recorded from the position of SP peak. We compared the SP/AP ratios of negative polarity and positive polarity graphs from the same ECoG of each patient by assuming different the position of SP peak. In addition, we attempted to evaluate the utility of two different manners of recording the ECoG graph in the diagnosis of Meniere's disease. SUBJECTS AND METHOD: Retrospectively, we analyzed the results of ECoG in 67 patients with unilateral definite Meniere's disease. ECoG was analyzed in two different manners. From the AP peak, the SP peak was determined close when positioned in the negative polarity; on the other hand, SP peak was considered distant when positioned in the positive polarity. The SP/AP ratio was interpreted with reference to the base line value. The ratio of two different ECoG values from each patient of Meniere's disease was calculated. RESULTS: In the abnormal side, the negative polarity ECoG showed significantly greater value of SP/AP ratio (mean: 0.334±0.10) than the positive polarity ECoG (mean: 0.283±0.09) (p<0.001). In the normal side, the negative polarity ECoG, showed significantly greater value of SP/AP ratio (mean: 0.250±0.09) than the positive polarity ECoG (mean: 0.204±0.06), as well as in the abnormal cases (p<0.001). CONCLUSION: The standard SP/AP ratio for the diagnosis of Meniere's disease can be variable according to the manner of determining the SP peak.
Action Potentials ; Audiometry, Evoked Response* ; Diagnosis ; Evoked Potentials ; Hand ; Humans ; Meniere Disease ; Methods ; Retrospective Studies

OBJECTIVES: To explore the relationship between the frequency characteristics and response threshold of auditory steady-state response (ASSR), auditory brainstem response (ABR) and 40 Hz auditory event related potential (40 Hz AERP), and their application values in forensic medicine. METHODS: Thirty volunteers with normal hearing (60 ears) were selected to perform pure tone audiometry (PTA) threshold and ASSR, ABR and 40 Hz AERP response threshold tests in the standard sound insulation shielding room, and the results were statistically analyzed by SPSS 22.0 software. RESULTS: At 0.5 kHz and 1.0 kHz frequencies, the correlation between 40 Hz AERP response threshold and PTA threshold was good, which was better than that of ASSR and ABR response threshold. At 2.0 kHz and 4.0 kHz frequencies, the correlation between ASSR and ABR response thresholds and PTA threshold was good, which was better than that of 40 Hz AERP response threshold. CONCLUSIONS To evaluate the hearing at 0.5 kHz and 1.0 kHz frequencies, it is recommended to use 40 Hz AERP and ASSR to comprehensively assess the PTA threshold of the subjects. To evaluate the hearing at 2.0 kHz and 4.0 kHz frequencies, ABR and ASSR are recommended to assess the PTA threshold of subjects comprehensively. The combination of ASSR, ABR and 40 Hz AERP can improve the accuracy of hearing function evaluation.
Acoustic Stimulation/methods* ; Audiometry, Evoked Response ; Audiometry, Pure-Tone ; Auditory Threshold/physiology* ; Evoked Potentials, Auditory, Brain Stem/physiology* ; Forensic Medicine ; Hearing/physiology* ; Humans

OBJECTIVE: To evaluate the accuracy with which auditory steady-state response (ASSR), tone burst auditory brain stem response (Tb-ABR) and click-evoked auditory brainstem response (c-ABR) thresholds predict behavioral thresholds, using a within-subjects design. METHOD: ASSR, Tb-ABR and c-ABR thresholds were recorded in a group of adults with normal hearing (58 ears). Evoked-potential thresholds were recorded and compared with behavioral, pure-tone thresholds. RESULT: The results suggested both ASSR and Tb-ABR thresholds had high correlations to pure-tone thresholds. Tb-ABR thresholds were recorded much closer to behavioral threshold than ASSR thresholds. There was a linear relation between c-ABR thresholds and average thresholds of 2 kHz, 4 kHz pure tone audiometry. CONCLUSION Both the ABR and the ASSR provided reasonably accurate predictions of multifrequencies behavioral threshold. Tb-ABR combined with c-ABR may take the accuracy predicted behavioral threshold.
Acoustic Stimulation ; Adolescent ; Adult ; Audiometry, Evoked Response ; methods ; Audiometry, Pure-Tone ; Auditory Threshold ; Evoked Potentials, Auditory, Brain Stem ; physiology ; Humans ; Young Adult

OBJECTIVE: To provide supports for the application of auditory evoked potential (AEP) in the evaluation of behavioral threshold, by studying the difference and relevance between the pure tone audiometry (PTA) and three frequency-specific auditory evoked potentials, including 40 Hz auditory event related potentials (40 Hz AERP), tone burst auditory brainstem response (Tb-ABR) and auditory steady-state response (ASSR). METHODS: Three frequency-specific AEP and PTA thresholds were recorded at speech frequency (0.5, 1, 2, 4 kHz) from thirty-four adults with normal hearing (68 ears). Then, the relationship between the AEP thresholds and PTA thresholds were analyzed respectively. RESULTS: There were good correlations between three frequency-specific AEP thresholds and PTA thresholds at speech frequency. However, the difference of thresholds between each frequency-specific AEP and PTA was not same. The difference of thresholds were the smallest and the relevance were the best between 40 Hz AERP and PTA at 0.5 kHz, and between ASSR and PTA at 2, 4 kHz. At 1 kHz, there were not statistical difference between ASSR, 40 Hz AERP and PTA, while the relevance of 40 Hz AERP was better than ASSR. CONCLUSION Different methods should be chosen to assess the objective behavioral thresholds at different frequency.
Acoustic Stimulation/methods* ; Adolescent ; Adult ; Audiometry, Evoked Response/methods* ; Audiometry, Pure-Tone ; Auditory Threshold/physiology* ; Evaluation Studies as Topic ; Evoked Potentials, Auditory ; Evoked Potentials, Auditory, Brain Stem/physiology* ; Female ; Forensic Medicine ; Humans ; Male ; Middle Aged ; Predictive Value of Tests ; Young Adult

OBJECTIVE: There were few recent study concern about usefulness of cochlear hydrops analysis masking procedure (CHAMP) in progression of Ménière's disease. The purpose of this study is to analyze changes in the CHAMP as advancement of Ménière's disease. METHODS: We studied 19 cases of ‘ Definite’ group of Ménière's disease. We assumed progression of Ménière's disease would be checked by pure tone threshold by four tone average (4PTA), low tone average (LPTA). We also compared electrocochleography (ECoG), dizziness handicap inventory (DHI), tinnitus handicap inventory (THI) as parameters for progression of Ménière's disease to CHAMP latency delay and amplitude ratio. Chi-square test was used as a statistical method. RESULTS: In the group of patients had abnormal amplitude ratio, ECoG value were not improved, but there was not statistically significant (odds ratio [OR]=5.727, p>0.05). Better DHI and THI score were not necessarily construed as the improvement value in the CHAMP (p>0.05). In amplitude ratio abnormal group, 4PTA was aggravated, but not statistically significant (OR=1.5, p>0.05). In the group of patient had abnormality in both latency delay and amplitude ratio, LPTA was relatively aggravated (OR in latency delay: 2, OR in amplitude ratio: 10); however, reveals no statistically significance between them (p>0.05). Change of ECoG, hearing threshold including 4PTA and LPTA with progression of Ménière's disease were not correlated significantly with latency delay or amplitude ratio of CHAMP. CONCLUSION: We conclude that CHAMP does not reflect clinical features with progression of Ménière's disease.
Audiometry, Evoked Response ; Dizziness ; Edema ; Endolymphatic Hydrops ; Hearing ; Hearing Loss ; Humans ; Masks ; Meniere Disease ; Methods ; Tinnitus ; Vertigo

OBJECTIVETo investigate the value of intraoperative auditory monitoring techniques in acoustic neuroma surgery.

METHODSTen cases with acoustic neuroma were resected with retrosigmoid approach. Continuous hearing monitoring of auditory brainstem responses (ABR) and transtympanic electrocochleography (ECochG) was performed during operation.

RESULTSBefore surgery, 3 patients had class A hearing, 4 had class B hearing, and 3 had class C hearing. With ABR monitoring, 5 patients had waves I , III and V, 5 had only waves I preoperation. After anesthesia,only 2 cases had waves I, III and V, 6 had wave I (Compound action potential, CAP N1 is equivalent to wave I of ABR) and 2 had no waves. The hearing was preserved in 2 cases, which had class A hearing post operation with tumor size <2 cm. With continuous hearing monitoring, the waves of I , III and V could be evoked in one case. In another case, the waves of I, III could be evoked after the tumor resection with the disappearance of wave V. The hearing was not preserved in 8 cases. The 6 out of 8 cases showed up CAP (waves I ) waveform. The CAP amplitudes decreased significantly in 4 cases and even dropped to zero while dissecting the tumor at the lateral end of the internal auditory canal (IAC) or clamping the internal auditory artery (IAA) during operation. After surgery, the CAP amplitudes were recovered to 50%-60% of normal level or normal. In one case, although the cochlear nerve was cut down, the CAP could still be recorded after the tumor resection. However, the CAP amplitudes was dropped to zero while pressurized and pulled cochlea nerve of brainstem lateral and the wave disappeared post-operation in another cases. The waves had not been recorded in two cases after anesthesia. One of them showed low amplitude of CAP wave when the tumor partially removed. The others had no wave all the time.

CONCLUSIONSIn combination with ABR monitoring, ECochG proved to be a useful supplementary tool for hearing preservation in acoustic neurinoma surgery. Drilling of the IAC and tumor removal at the lateral end of the IAC were the most critical steps for achieving hearing preservation. The surgeon's experience are the most significant factors influencing the hearing outcome after removal of acoustic neuroma.

Adolescent ; Adult ; Audiometry, Evoked Response ; Cochlear Nerve ; physiopathology ; Evoked Potentials, Auditory, Brain Stem ; Female ; Humans ; Male ; Middle Aged ; Monitoring, Intraoperative ; methods ; Neuroma, Acoustic ; physiopathology ; surgery ; Young Adult

OBJECTIVE: To study the value of slow vertex response (SVR) in the evaluation of hearing loss by comparing the hearing thresholds acquired with SVR and pure tone audiometry (PTA). METHODS: Twenty-five subjects (40 ears) with sensorineural hearing loss were tested by PTA and SVR. According to the thresholds of PTA, these ears were subdivided into mild, moderate and severe hearing loss groups, and rank sum test was performed on the thresholds of SVR and PTA for all the hearing loss groups. Then, the correlation between PTA thresholds and SVR thresholds was analyzed and the mathematical models were established for predicting behavioral thresholds by the thresholds of SVR. RESULTS: At four test frequencies (0.5, 1, 2 and 4kHz), the thresholds of SVR had high correlations with thresholds of PTA. Four liner regression equations were established, and the correlation coefficient(r) were 0.971, 0.976, 0.957 and 0.928, respectively (P < 0.05). Back substitution test showed that the liner regression equations would be an easy method for estimating the behavior thresholds. CONCLUSION The behavioral threshold can be well judged and evaluated by the liner regression equations established with SVR thresholds.
Acoustic Stimulation/methods* ; Audiometry, Evoked Response ; Audiometry, Pure-Tone ; Auditory Cortex/physiology* ; Auditory Threshold/physiology* ; Evoked Potentials, Auditory/physiology* ; Female ; Forensic Medicine/methods* ; Hearing Loss/physiopathology* ; Humans ; Male ; Predictive Value of Tests ; Regression Analysis ; Severity of Illness Index

OBJECTIVE: To compare the results between auditory steady-state response (ASSR) and 40 Hz auditory event related potential (AERP), and explore the accuracy of hearing thresholds by using ASSR and AERP and the clinic forensic value. METHODS: Thirty seven ears were tested with pure-tone audiometer, 40Hz AERP and ASSR, respectively. All the volunteers in our study were awake during 40 Hz AERP test and ASSR test. RESULTS: Thresholds acquired with ASSR and 40Hz AERP test had a close correlativity and showed higher than those acquired with PTA test. There was no significant difference between the accuracy of ASSR and 40Hz AERP in estimating pure-tone thresholds. CONCLUSION After determining the correct value, ASSR can be used directly to evaluate hearing loss objectively.
Acoustic Stimulation ; Adult ; Audiometry, Evoked Response ; Audiometry, Pure-Tone/methods* ; Auditory Threshold ; Evaluation Studies as Topic ; Evoked Potentials, Auditory, Brain Stem/physiology* ; Female ; Hearing Loss, Sensorineural/physiopathology* ; Humans ; Male ; Middle Aged ; Predictive Value of Tests ; Sleep/physiology* ; Wakefulness ; Young Adult

OBJECTIVE: To investigate the value of slow vertex response (SVR) for forensic appraisement of hearing dysfunction by comparing the thresholds acquired with SVR and pure tone audiometry (PTA). METHODS: Forty-six subjects with normal hearing were tested with PTA (0.125-8 kHz) and SVR (0.5-4 kHz). Paired t-test analysis was performed on the thresholds of SVR and PTA at each frequency (0.5, 1, 2 and 4 kHz), and analysis of variance was performed on the difference between the pure tone audiometry threshold and the evoked potential threshold among different frequency. RESULTS: At each frequency(0.5, 1, 2 kHz and 4 kHz), difference between the thresholds acquired with SVR and PTA was statistically significant(P < 0.05). The mean difference of the two thresholds were (5.98 +/- 6.72) dB HL at 0.5 kHz, (3.86 +/- 6.12) dB HL at 1 kHz, (7.12 +/- 6.56) dB HL at 2 kHz, (8.53 +/- 7.90) dB HL at 4kHz, and the mean difference at 1 kHz was the smallest. This variation between frequencies was also statistically significant. CONCLUSION The thresholds acquired with SVR were higher than those acquired with PTA. The adjusted thresholds should be established at each frequency, when the SVR thresholds are used to evaluate the behavioural hearing thresholds.
Acoustic Stimulation ; Adult ; Analysis of Variance ; Audiometry, Evoked Response/methods* ; Audiometry, Pure-Tone ; Auditory Cortex/physiology* ; Auditory Threshold/physiology* ; Evoked Potentials, Auditory ; Female ; Hearing Disorders/diagnosis* ; Humans ; Male ; Middle Aged ; Reaction Time ; Young Adult

BACKGROUNDBlood oxygen level dependent functional magnetic resonance imaging (fMRI) and magnetoencephalography are new techniques of brain functional imaging which can provide the information of excitation of neurons by measure the changes of hemodynamics and electrophysiological data of local brain tissue. The purpose of this study was to study functional brain areas evoked by pure tones in healthy and sensorineural hearing loss subjects with these techniques and to compare the differences between the two groups.

METHODSThirty healthy and 30 sensorineural hearing loss subjects were included in this study. In fMRI, block-design paradigm was used. During the active epoch the participants listened to 1000 Hz, sound pressure level 140 dB pure tones at duration 500 ms, interstimulus interval 1000 ms, which presented continuously via a magnetic resonance-compatible audio system. None stimulus was executed in control epoch. In magnetoencephalography study, every subject received stimuli of 1000 Hz tone bursts delivered to the bilateral ear at duration 8 ms, interstimulus intervals 1000 ms. Sound pressure level in healthy subjects was 30 dB; in sensorineural hearing loss subjects was 20 dB above everyone's hearing threshold respectively. All subjects were examined with 306-channel whole-scalp neuromagnetometer.

RESULTSIn fMRI, all subjects showed significant activations in bilateral Heschl's gyri, anterior pole of planum temporale, planum temporale, precentral gyri, postcentral gyri, supramarginal gyri, superior temporal gyri, inferior frontal gyri, occipital lobes and cerebellums. The healthy subjects had more intensive activation in bilateral Heschl's gyri, anterior pole of planum temporale, inferior frontal gyri, left superior temporal gyri and right planum temporale than the hearing loss subjects. But in precentral gyri, postcentral gyri and occipital lobes, the activation is more intensive in the hearing loss subjects. In magnetoencephalography study, both in the hearing loss and the healthy subjects, the most evident audio evoked fields activated by pure tone were N100m, which located precisely on the Heschl's gyrus. Compared with the hearing loss subjects, N100m of the healthy subjects was stronger and had longer latencies in right hemisphere.

CONCLUSIONSUnder proper pure tone stimulus the activation of auditory cortex can be elicited both in the healthy and the sensorineural hearing loss subjects. Either at objective equivalent stimuli or at subjectively perceived equivalent stimuli, the auditory responses were more intensive in healthy subjects than hearing loss subjects. The tone stimuli were processed in a network in human brain and there was an intrinsic relation between the auditory and visual cortex. Blood oxygen level dependent fMRI and magnetoencephalography could reinforce each other.

Acoustic Stimulation ; Adolescent ; Adult ; Audiometry, Evoked Response ; Audiometry, Pure-Tone ; methods ; Auditory Cortex ; physiology ; physiopathology ; Brain ; physiology ; physiopathology ; Female ; Hearing Loss, Sensorineural ; chemically induced ; physiopathology ; Humans ; Magnetic Resonance Imaging ; methods ; Magnetoencephalography ; methods ; Male ; Occipital Lobe ; physiology ; physiopathology