Time Course of the Suppression Effect on Transient Evoked Otoacoustic Emissions by Prolonged Contralateral Acoustic Stimulation

BACKGROUND AND OBJECTIVES: Although the suppressive effect of the medial efferent acoustic reflex is well known, the time course of this effect over prolonged periods has yet to be fully evaluated. We assessed time-dependent change in the suppression of transient evoked otoacoustic emissions (TEOAEs) by the medial efferent acoustic reflex over a relatively long period. SUBJECTS AND METHODS: We measured TEOAEs in the right ear before contralateral acoustic stimulation (CAS), and then measured serial TEOAEs in the right ear at four intervals during a total of 16 minutes of continuous CAS, followed by three more recordings after termination of CAS. RESULTS: TEOAE amplitudes were reduced with CAS during a certain period (from the immediate period to 10 minutes depending on frequency) and subsequently recovered. TEOAE suppression values in the mean amplitudes for overall frequency were 0.76 dB at the initial recording, 0.35 dB at 5 minutes, 0.44 dB at 10 minutes, and 0.33 dB at 15 minutes during CAS. The initial suppression value was significantly larger than other suppression values of 5, 10, and 15 minutes (p<0.05). In recordings obtained after CAS, TEOAE amplitude exceeded pre-acoustic amplitudes at 1 kHz, 1.5 kHz, and 2 kHz. CONCLUSIONS: The present results show the existence of the medial efferent acoustic reflex and demonstrate the time course that TEOAE suppressions present initially after CAS, showing fatigue over time. Overshooting of TEOAE was observed in recordings at several frequencies after termination of CAS.

Time Course of the Suppression Effect on Transient Evoked Otoacoustic Emissions by Prolonged Contralateral Acoustic Stimulation

BACKGROUND AND OBJECTIVES: Although the suppressive effect of the medial efferent acoustic reflex is well known, the time course of this effect over prolonged periods has yet to be fully evaluated. We assessed time-dependent change in the suppression of transient evoked otoacoustic emissions (TEOAEs) by the medial efferent acoustic reflex over a relatively long period. SUBJECTS AND METHODS: We measured TEOAEs in the right ear before contralateral acoustic stimulation (CAS), and then measured serial TEOAEs in the right ear at four intervals during a total of 16 minutes of continuous CAS, followed by three more recordings after termination of CAS. RESULTS: TEOAE amplitudes were reduced with CAS during a certain period (from the immediate period to 10 minutes depending on frequency) and subsequently recovered. TEOAE suppression values in the mean amplitudes for overall frequency were 0.76 dB at the initial recording, 0.35 dB at 5 minutes, 0.44 dB at 10 minutes, and 0.33 dB at 15 minutes during CAS. The initial suppression value was significantly larger than other suppression values of 5, 10, and 15 minutes (p<0.05). In recordings obtained after CAS, TEOAE amplitude exceeded pre-acoustic amplitudes at 1 kHz, 1.5 kHz, and 2 kHz. CONCLUSIONS: The present results show the existence of the medial efferent acoustic reflex and demonstrate the time course that TEOAE suppressions present initially after CAS, showing fatigue over time. Overshooting of TEOAE was observed in recordings at several frequencies after termination of CAS.

Analysis of Correlation between Cognitive Function and Speech Recognition in Noise / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Speech in the noise test has been known to reflect the distortion component of hearing impairment originated not only from the cochlea but also from the central auditory system. For communication with language, a proper cognitive function of the cerebral cortex is essential. In the present study, we aimed to evaluate the correlation between the cognitive function and the speech recognition ability against background noise. SUBJECTS AND METHOD: Thirty one listeners with sensorineural hearing loss in both ear participated in this study. We performed pure a tone audiometry, a speech recognition test with and without multitalker babble noise, a computerized cognitive function test and the Mini-Mental Status Examination-Korea. RESULTS: Speech recognition score in noise showed significant correlations with the results of both computerized cognitive function test and Mini-Mental Status Examination-Korea, whereas, the pure tone average and speech recognition score in the quiet background did not. CONCLUSION: These results support that speech recognition ability in background noise reflects the cognitive function.

A Case of Peripheral Osteoma in External Maxilla / 대한이비인후과학회지

Osteoma is a benign tumor characterized by proliferation of compact or cancellous bone that may form peripherally in a periosteal location or in central position. The most common site of the peripheral osteoma in the craniofacial area is the frontal sinus, and the extremely rare site is found to be in the external maxilla. Clinically, it appears round and shows slow growth without symptoms but its large size results in facial asymmetry, tenderness and swelling. Radiologically, peripheral osteoma appears as a well-circumscribed radiopacity and histologically shows proliferation of either compact or cancellous bone. The etiology of osteoma in maxilla is uncertain, but it has been suggested that they are frequently associated with infection or trauma. The treatment is surgical excision. We report a case of peripheral osteoma on the right anterior maxilla in 53-year-old female patient who complained of cheek discomfort and tenderness. Surgical excision was performed and the patient was followed up for 7 months without recurrence.