Short-term pathophysiologic changes and histopathologic findings of the auditory pathway after closed head injury, using a rabbit model.

Hearing impairment is a well-known consequence of closed head injury (CHI). The aim of this study was to elucidate the pathogenesis of CHI-induced hearing loss, using a rabbit model. Twelve New Zealand white rabbits were divided into two groups of 6. In the first group, CHI was induced mechanically, whereas the rabbits of the second group served as controls. Baseline distortion product otoacoustic emissions (DPOAEs), contralateral suppression (CS) of the DPOAEs and auditory brainstem response (ABR) were obtained. The same measurements were performed in the first group after CHI. Three hours later, the animals were sacrificed and their brain was excised and subjected to histopathologic examination. Mean I-III ABR latencies were increased and DPOAE amplitudes and CS values were reduced in the trauma group after CHI, at a statistically significant level. Histopathologic examination of the temporal lobe and brainstem showed multiple hemorrhagic and necrotic areas, with edema in the surrounding region. The vestibulocochlear nerve was severely damaged at its emerging site at the brainstem. In conclusion, both peripheral and central involvement of the auditory pathway was found after CHI. Otoacoustic emissions in conjunction with ABR may provide significant information on both peripheral and central auditory function.

The effect of impulse noise on distortion product otoacoustic emissions.

The aim of this study was the evaluation of distortion product otoacoustic emissions (DPOAEs) before and after noise exposure from shooting, and the comparison of DPOAEs with pure-tone audiometry. Thirteen young male police officers were exposed to impulse noise from shooting, without using earplugs. Standard pure-tone audiometry, tympanometry, and DPOAEs were performed before exposure and at one hour post- and 24 hour post-exposure. In the one hour post-exposure testing mean pure-tone thresholds were elevated in the 1-8 kHz frequency zone and DPOAE levels were reduced at several frequencies. DPOAEs were more affected at 3 kHz or lower, whereas pure-tone thresholds were more affected at higher frequencies. After the final examination, non-significant partial shifts at high frequencies on both tests remained. Pure-tone audiometry was overall more sensitive, but DPOAEs provided additional information about the cochlear status of certain ears. These data suggest that besides behavioral testing, DPOAEs may play a role as a fast, objective, and easy to perform test for monitoring subjects exposed to impulse noise.

Management of epistaxis in hereditary hemorrhagic telangiectasia by Nd:YAG laser and quality of life assessment using the HR-QoL questionnaire.

The purpose of this study was to describe the results of Nd:YAG laser application in hereditary hemorrhagic telangiectasia (HHT) patients and to measure the Health-Related Quality of Life (HR-QoL) in patients with HHT before and after Nd:YAG laser application in a prospective, clinical trial at a university hospital. Twenty-seven consecutive patients with HHT and mild to moderate degrees of epistaxis were followed-up for 2 years after Nd:YAG laser treatments. Recurrence of epistaxis after Nd:YAG laser application and measurement of HR-QoL using the International Quality of Life Assessment questionnaire, version 1.1 (IQOLA 1.1), was found. Eight patients (30%) received only one Nd:YAG laser treatment, 15 (56%) had a recurrence and received a second treatment and 4 (14%) had two recurrences and received three Nd:YAG laser treatments. HR-QoL was improved 2 years after the first Nd:YAG laser application in both its Physical Health Dimension (47.5+/-2.9 vs. 38.1+/-2.3 before treatment, P <0.05) and Mental Health Dimension (45.1+/-2.7 vs. 39.6+/-2.4 before treatment, P <0.05). Although no curative treatment for HHT exists, Nd:YAG laser treatment seems to constitute a simple and efficient method of epistaxis control, resulting in a significant improvement in quality of life.