The minimum speech test battery in profound unilateral hearing loss.

OBJECTIVE: Individuals with monaural hearing experience disadvantages compared with normal hearing counterparts because of the loss of the head shadow effect, the squelch effect, and binaural summation. In this study the Minimum Speech Test Battery (MSTB), a battery designed to document word recognition in bilaterally hearing impaired cochlear implant candidates, was administered to unilaterally hearing-impaired and normal hearing subjects to study its possible use in measuring hearing difficulty in monaural subjects. STUDY DESIGN: Repeated measures design with the MSTB administered in sound-field in a sound-isolated booth in 1) quiet; 2) speech toward good ear, noise (+10 dB S/N) toward impaired ear; 3) speech toward impaired ear, noise toward good ear; and 4) bilateral speech and noise. SETTING: Academic otologic practice. PATIENTS: Ten adults with normal hearing and 10 adults with normal or near-normal hearing in one ear and profound hearing loss in the contralateral ear. MAIN OUTCOME MEASURES: The MSTB, composed of the Consonant-Nucleus-Consonant (CNC) test and the Hearing In Noise Test (HINT). RESULTS: As expected, performance differences between the groups were not found in quiet conditions. Analysis of variance and regression analysis confirmed that the impaired group performed significantly worse than control subjects on HINT testing when noise was directed toward the good ear. Analysis of variance and regression analysis confirmed that the impaired group performed significantly worse than control subjects on CNC testing when noise was directed toward the good ear and in bilateral noise. CONCLUSIONS: The MSTB may be useful in measuring the hearing difficulty of patients with monaural hearing.

Mastoid oscillation in canalith repositioning for paroxysmal positional vertigo.

OBJECTIVE: The canalith repositioning procedure (CRP) was developed to treat paroxysmal positional vertigo (PPV). Successful CRP results in cessation of PPV and positional nystagmus. Mastoid oscillation (MO) has been advocated to enhance the efficacy of CRP. The authors sought to objectively determine the effect of MO on CRP. STUDY DESIGN: Retrospective review. SETTING: Ambulatory referral center. PATIENTS: Patients with PPV seen from 1993 through 1999 (N = 168). INTERVENTIONS: Canalith repositioning procedure performed without MO (n = 104) and performed with MO (n = 64). MAIN OUTCOME MEASURE: Presence or absence of nystagmus on Dix-Hallpike testing 6 weeks after CRP. RESULTS: Eighty-four percent of patients treated with MO had resolution, and 16% had persistent nystagmus. Seventy-three percent of patients without MO had resolution, and 27% had persistent nystagmus. Although suggesting a trend, the difference did not reach the level of significance (p = 0.151). CONCLUSIONS: Mastoid oscillation does not significantly enhance the efficacy of the CRP.

The effects of click rate on the auditory brain stem response (ABR) in patients with varying degrees of HIV-infection: a pilot study.

This study investigated the effects of click rate on the latencies of the auditory brain stem response (ABR) in subjects with varying degrees of HIV-infection. ABRs were evoked with broad-band clicks presented at rates of 21.1/sec and 61.1/sec in 13 AIDS patients, 9 HIV-infected patients, and 9 HIV-negative volunteers. The latency of waves I, III, and V were measured and analyzed. Statistically significant delays in wave V latency utilizing both click rates occurred for the AIDS group only, however, a comparison of the wave V latency group means obtained with both click rates revealed a demographic pattern that may be indicative of early neurological involvement in asymptomatic HIV-infected individuals.

Effects of hyperthermia on the auditory-evoked brainstem responses in mice.

This study investigated the effects of increased body temperature on the latencies and amplitudes of the auditory-evoked brainstem response (ABR) in mice. Six eleven-week-old male CBA/CaJ mice were anesthetized with pentobarbital and screened for normal hearing. Hyperthermia was induced by placing the animal in a thermostatically controlled chamber; a thermistor connected to a digital thermometer measured the rectal temperature. ABRs were evoked with broad-band clicks presented at repetition rates of 21.1/s and 61.1/s. The latencies and amplitudes of waves I-V were measured at 1-degree and/or 0.5-degree intervals between 37 and 42 degrees C. Temperature elevation between 37 and 41 degrees C shortened the latencies of all the ABR waves, the effect being linear and cumulative across the time window. Change in this trend occurred between 41 and 42 degrees C, whereby the latencies of all the waves stabilized or showed minimal prolongation. Amplitudes of the most robust waves I and II showed a trend similar to the latencies, whereas the later waves showed erratic and uninterpretable changes. These findings in the mouse may be indicative of the physiological limit of thermal tolerance and as such may be regarded as a premonitory signal of permanent damage.