Biomedical subjects

Angelo Scaringi

Publications and source records attributed to Angelo Scaringi.

4 recordsLinked to original sources

PubMed2005

Effects of efferent acoustic reflex activation on psychoacoustical tuning curves in humans.

CONCLUSIONS: The results show that, in humans, activation of the contralateral EAR makes the PTC narrower at 1 kHz but wider at 4 kHz. These data are consistent with those reported previously in animals and demonstrate that, during medial efferent stimulation in humans, frequency resolution is improved at low frequencies but impaired at high frequencies. OBJECTIVE: To evaluate, in humans, the effect of activation of the contralateral efferent acoustic reflex (EAR) on the psychoacoustical tuning curves (PTCs) recorded for 1- and 4-kHz probe tones. MATERIAL AND METHODS. Ten young (20-30 years) volunteers served as subjects. They had normal hearing (thresholds <20 dB HL in the frequency range 0.25-8 kHz) and a functioning EAR (contralateral suppression of transient-evoked otoacoustic emissions > or = 0.8 dB). Frequency resolution was evaluated using PTCs. PTCs were recorded at 1 and 4 kHz using a simultaneous masking method. Q10 and Q20 were calculated as the ratio between the test frequency and the bandwidth of the PTC at 10 and 20 dB above the tip of the curve, respectively. The EAR was activated with a 40-dB SL contralateral narrow-band noise centered on the characteristic frequency of the PTC (1 or 4 kHz). Q10 and Q20 were measured in the presence and absence of the contralateral noise. RESULTS: Activation of the EAR led to a significant increase (p < 0.001) in Q10 at 1 kHz and a significant decrease (p <0.001) at 4 kHz. Changes in the value of Q20 were not significant.

Acoustic Stimulation↗

PubMed2004

The effects of 'supra-physiological' vitamin B12 administration on temporary threshold shift.

The aim of this study was to evaluate, in 20 young volunteer subjects, the effects of supra-physiological vitamin B12 administration on noise-induced temporary threshold shift (TTS). All subjects had hearing thresholds within 15 dBHL and type A tympanograms. The subjects were randomly assigned to two different groups. Experimental group subjects received cyanocobalamin, 1 mg daily for 7 days, and 5 mg on the eighth day. Control group subjects received a placebo injection daily for 8 days. The vitamin B12 concentration, hearing thresholds and TTS2 (10 min of exposure, narrowband noise centred at 3 kHz, bandwidth of 775 Hz, 112 dBSPL) were measured before and 8 days after treatment. At the end of treatment, the serum vitamin B12 concentration was significantly increased in the experimental group. After 8 days of treatment, the control group showed the same hearing thresholds and TTS2 degrees. Statistical analysis showed that TTS2 decreased significantly at 3 and 4kHz when cobalamin was used to increase the serum concentration of vitamin B12 to > 2350 pg/ml. In addition, a protective effect at 3 kHz in the experimental group was evident when compared with the placebo group. These results suggest that elevated plasma cyanocobalamin levels may reduce the risk of hearing dysfunction resulting from noise exposure in healthy, young subjects.

Adult↗

PubMed2003

Effect of ipsilateral and contralateral low-frequency narrow-band noise on temporary threshold shift in humans.

OBJECTIVE: To evaluate the effect of ipsilateral and contralateral low-frequency (250 Hz) narrow-band noise (NBN) on the temporary threshold shift (TTS) induced by a 2 kHz tone in young normally hearing subjects with a functioning auditory efferent system. MATERIAL AND METHODS: Sixteen young volunteers served as subjects. All the subjects were young (20-30 years), disease-free and had a medical history negative for otological disease, noise exposure and use of ototoxic drugs. They had normal hearing [thresholds of 125-8,000 Hz below 20 dB hearing level (HL)], transient-evoked otoacoustic emissions and contralateral suppression. The subjects were randomly assigned to one of three different groups. Subjects in Group A (n = 5) were exposed to a 90 dB HL 2 kHz pure tone for 10 min. Subjects in Group B (n = 6) were exposed to a 90 dB HL 2 kHz pure tone and an ipsilateral 45 dB HL 250 Hz NBN for 10 min. Subjects in Group C (n = 5) were exposed to a 90 dB HL 2 kHz pure tone and a contralateral 45 dB HL 250 Hz NBN for 10 min. The right ear served as the test ear. The TTS 2 min after the end of the exposure (TTS2) was measured in all subjects at 2, 3 and 4 kHz. RESULTS: TTS, in Group A was significantly higher at 3 kHz (p = 0.011) and at 4 kHz (p = 0.003) than TTS2 in Group B. At 4 kHz, TTS2 in Group C was significantly higher (p = 0.013) than TTS2 in Group B. Although TTS2 in Group C was lower than TTS2 in Group A, this difference was not significant. The presence of an ipsilateral low-frequency NBN significantly reduced TTS2 induced by a 90 dB HL 2 kHz tone. A contralateral low-frequency NBN reduced TTS2 in this group of subjects; however, the reduction was not significant. CONCLUSION: The results of this study show that an ipsilateral low-intensity, low-frequency (250 Hz) NBN can give protection from a TTS induced by a 2 kHz tone. Contralateral low-frequency NBN did not induce any protective effect.

Acoustic Stimulation↗

PubMed2002

Cochlear function in ears with immunomediated inner ear disorder.

The aim of the present study was to evaluate the performance of ears with inner ear disorder, responsive to immunosuppressive drugs, in advanced tests designed to assess primary cochlear functions (temporal integration, frequency selectivity, cochlear mechanics). The results of this study suggest that immunomediated inner ear disease results, in the acute clinical stage, in the development of endolymphatic hydrops, which increases the stiffness of the vibrating structures within the inner ear and causes dysfunctions of the outer hair cells. Our patients presented with upsloping or flat sensorineural hearing loss, absence of evoked otoacoustic emissions and distortion-product otoacoustic evoked emissions and abnormal temporal integration, frequency selectivity and cochlear mechanics. Following immunosuppressive treatment, hydrops recovered, hearing subsequently returned to normal, the audiometric curve became flat at low-to-middle frequencies and primary cochlear function tended to normalize. This study seems to support the usefulness of testing primary cochlear functions in order to monitor the clinical course of immunomediated inner ear disorders.

Acoustic Impedance Tests↗