[The diagnostic value of TEOAE-glycerine test in patients with vertigo on the first attack].

OBJECTIVE: To investigate the diagnostic value of transiently evoked otoacoustic emissions (TEOAE) combined with glycerine test in patients with vertigo on the first attack. METHOD: PTT and TEOAE-glycerine test were conducted on the 28 patients who suffered the first attack of vertigo without hearing loss, tinnitus or a sensation of fullness in the ear. At the same time, history and clinical manifestation of the patients were not supportive for the non-Meniere's disease. RESULT: Among the 28 cases, four of them had nothing changed on the PTT and TEOAE parameters after glycerol administration, all of the indexes were in the normal range. Among the 20 positive cases in the TEOAE-glycerine test (unilateral ear 16 cases, bilateral ears 4 cases), TEOAE for 2 cases were not evoked before glycerol administration, while it was evocable after glycerol administration. For the positive ears, all of the parameters of TEOAE were lower than those in the normal standard before and after glycerol administration; there were 4 positive cases in the PTT glycerine test, however, both TEOAE were not evoked before and after glycerol administration. CONCLUSION: TEOAE-glycerine test can be used as a routine method for the early diagnosis of Meniere's disease and differentiating diagnosis in the patients who suffer vertigo on the first attack with normal hearing.

[Probe to the bone-conduction phenomenon].

OBJECTIVE: To probe into the rule of bone-conduction measurement by testing a group of health young students with normal hearing and groups of case with different diseased ears, in order to provide some instructions for clinical audiometry. METHOD: Subjects included 20 health young students with normal hearing, 113 cases with different hearing loss. We tested all the subjects Weber Test and bone-conduction threshold by masking. RESULT: Weber Test lateralization dependented on the difference of binanural sensitivity when binaural had no conductive impairment. Different conductive impairment improved bone-conduction response at different frequencies. When monaural had conductive impairment and the other ear normal, there were 3-5 octaves WT lateralizated to the diseased ear. When there were binaural conductive impairments, bone-conduction response dependented on the nature and degree of the impairment, WT lost the rule. CONCLUSION: In order to avoid the negative effects of central masking and overmasking, our observations came to the conclusion that some conditions as follow need no masking: (1) There are no conductive impairment binaural, and the air-conduction pure tone threshold (PTT) gap between binaural higer than 40 dB, when we test bone-conduction PTT of better ear, we need no masking, as for the poor ear, it's bone conduction will come cross to the contralateral ear. (2) When one ear normal and the other is the conductive impairment,need no masking when testing the diseased ear. (3) There are conductive impairments binaural, bone-conduction PTT is normal, and air-conduction PTT is higher than interaural attenuation, we cannt get a true bone-conduction PTT by masking, but can determine the type of hearing loss and estimate the integrity of the sensory-neural system by other audiometry measurements.

[A study on the correlation between distortion product otoacoustic emissions and transient evoked otoacoustic emissions].

OBJECTIVE: To study the characteristic and correlation of distortion product otoacoustic emissions and transient evoked otoacoustic emissions. METHOD: Contrast Band SNR and Band response amplitude of TEOAE with 2f1-f2 amplitude and SNR of DPOAE were investigated in states before or after noise exposure with or without contralateral suppression(CS) in 20 (40 ears) normal otologic youth volunteer subjects. RESULT: Although evoked by different acoustic stimulus and showed various characteristics of patterns respectively, DPOAE and TEOAE had a good correlation between their measuring values at most adjacent frequencies thus formed certain value relation. CONCLUSION: TEOAE measurement is save time and superior in middle frequency range while DPOAE measurement is better frequency specific and superior in the higher frequency. Between their amplitude and SNR there were good correlations so significant linear regression parameters can be obtained. According to these mentioned above they could be selected and used, moreover, make up a deficiency each other in scientific research and clinical practice.

[Effects of sodium salicylate and extracellular K(+) on outward potassium current and resting potential of outer hair cell isolated from guinea pig cochlea].

OBJECTIVE: To investigate the effects of sodium salicylate and extracellular K(+) on the functions of outer hair cells (OHCs) and the relations between their actions. METHODS: Sodium salicylate at the concentration of 1 mmol/L was administered either alone or following 10 mmol/L KCl into the extracellular solution of OHCs isolated from guinea pig cochlea. The outward potassium current (IK) and resting potential (RP) of OHCs was measured using patch-clamp whole cell recording technique. RESULTS: Time-dependent changes in the effect of sodium salicylate on IK was observed, namely, IK underwent transient increase and then declined after sodium salicylate administration. When KCl was administered previously into the extracellular solution, the effect of sodium salicylate on IK was reduced. Sodium salicylate could decrease RP but not time-dependently in the absence of KCl, and when prior KCl treatment was administered, only temporary increase in RP took place before RP returned to the level before sodium salicylate administration.?? CONCLUSIONS: The effects of sodium salicylate on OHC functions were related to K(+), and the former agent may affect K(+) conduction and internal and external distribution of K(+) in OHCs, and causes the changes in the excitability and mechanical activity of OHCs by means of affecting IK and RP. This hypothesis might be one of the cochlear mechanisms by which sodium salicylate affects OHC functions.

[The appearance of contralateral otoacoustic emissions with unilateral cochlear hearing loss].

OBJECTIVE: To investigate the latent influence on the contralateral ear when one ear was involves by different deaf elements. METHOD: TEOAE and DPOAE were recorded from contralateral ears with unilateral cochlear hearing loss, who were divided into 5 groups, group S1, sudden deafness last within two months (9 ears), group S2, sudden deafness last over one year or so(6 ears), Meniere's disease (13 ears M1, M2) cochlear hearing loss of unknown etiology(7 ear, UNK), using ILO-96 analyzer system. RESULT: Response amplitude, wave reproducibility, band reproducibility of TEOAE in S1, M2 were significantly lower than normal values. Amplitude of DPOAE in S1, M2 were significantly lower than normal values. All record were the same with normal in S2, M1. UNK. CONCLUSION: In all sorts of deaf elements, some have an effect on binaural ears, the others have an effect on unilateral ear.

[A study on the effects of contralateral acoustic suppression to transient evoked otoacoustic emissions after noise exposure].

OBJECTIVE: To investigate the effects of contralateral acoustic suppression(CAS) on transient evoked otoacoustic emissions(TEOAE) in Noise Exposure Condition, in order to explore the effects of efferent positive feedback regulation on the cochlear mechanisms and the effects of CAS on the sensitivity of TEOAE measure for finding changes of cochlear function condition induced by noise exposure. METHOD: Observing the effects of CAS (60 dB SPL WN) on the changes of TEOAE parameters, Response Amplitude, Reproducibility, Band SNR and Band Reproducibility, before and after noise exposure. RESULT: The values of every index of TEOAE were decreased respectively so that the effects of noise exposure on cochlear function can be reflected sensitively. A small decrease of values can be induced by CAS before noise exposure, of some decrease of indices were significant. After noise exposure, the changes of TEOAE parameters become much more with CAS than without. CONCLUSION: Noise exposure can effect obviously cochlear function condition and decrease OAE measurement values. CAS had suppressing action on cochlear activity by a negative feedback and can increase obviously the sensitivity of TEOAE measurement in finding the changes induced by noise exposure.