Auditory brainstem response

Co-exposure to -hexane and xylene resulted in a loss of auditory sensitivity in male Sprague-Dawley rats (Nylen et al. 1994) as measured by the auditory brainstem response. Exposure to -hexane or xylene alone at 1,000 ppm for 61 days for 18 hours a day caused a slight loss of auditory sensitivity when measured 2 days after the end of exposure. Simultaneous exposure to w-hexane and xylene (1,000 ppm each) caused a greater and persistent loss of auditory sensitivity which was greater than the sum of effects of exposure to w-hexane and xylene separately. These effects were still observed 4 and 10 months after exposure ended. In contrast, combined exposure to -hexane and xylene partially reversed the decreased nerve conduction velocities and action potential amplitudes observed in the group treated with 77-hexane alone. These effects were persistent from 2 days to 10 months after cessation of exposure. 

Muscle tremors and convulsions are characteristic effects of acute dermal phenol toxicity in laboratory animals. Tremors that developed into convulsions and prostration were reported in rats exposed to 107.1 mg/kg liquid phenol application surface areas were not reported (Conning and Hayes 1970). In pigs, application of 500 mg/kg over 35-40% of the body surface (0.44 mg/cm2/kg) resulted in muscular tremors in the head region within 3-5 minutes of exposure (Pullin et al. 1978). This was followed by dilation of the pupils, loss of coordination, and excess salivation and nasal discharge within 5 minutes of exposure. It was followed by convulsions, coma, and death 5-7 minutes after exposure in two of three pigs. Direct application of a dose of 37.5 mg/kg phenol to the inner ear resulted in a reduced threshold for auditory brainstem response (Schmidt et al. 1990). 

Other Systemic Effects. Direct application of phenol to the tympanic membrane in the ear of rats resulted in inflammation (Schmidt and Hellstrom 1993). When phenol was placed in the ear of rats after tympanic membrane puncture, inflammation and a reduction in auditory brainstem response were observed (Schmidt et al. 1990). These studies indicate that direct application of phenol to the ear for treatment of ear infection should be used with caution. 

The auditory brainstem responses (ABR) in neonates who were exposed prenatally to cocaine showed prolonged absolute peak latencies compared with non-exposed neonates and may indicate compromise of the auditory system from gestational exposure to cocaine (333). Among 58 infants studied, 21 (36%) were positive by meconium analysis for cocaine, and five (8.5%) were also positive for cannabinoids. There were significant differences in mean maternal age, gravidity, parity, birth weight, and head circumference among cocaine-exposed infants. 

Tan-Laxa MA, Sison-Switala C, Rintelman W, Ostrea Jr EM. Abnormal auditory brainstem response among infants with prenatal cocaine exposure. Pediatrics 2004 113 357-60. 

Hotz MA, Ahum JH, Kaufmann G, FoUath F, Pfaltz CR. Shifts in auditory brainstem response latencies following plasma-level-controlled aminoglycoside therapy. Eur Arch Otorhinolaryngol 1990 247(4) 202-5. 

Topical 0.2% ciprofloxacin (0.2 ml od for 7 days) did not significantly affect the auditory brainstem response thresholds of guinea pigs, whereas 4% gentamicin (0.2 ml od for 7 days) resulted in total hearing loss (19). 

Auditory brainstem responses have been used to detect ototoxicity from cisplatin and carboplatin when used in combination therapy (95). 

Auditory brainstem responses have been used to detect ototoxicity from cisplatin and carboplatin when used in combination therapy (95). The method can detect early high frequency damage due to these drugs up to two or three cycles earlier than conventional audiometry. 

Bourre J, Durand G, Erre J, et al. Changes in auditory brainstem responses in alpha-linolenic acid deficiency as a function of age in rats. Audiology 1999 38 8-13. 

Wassick, K.H., and A. Yonovitz. 1985. Methyl mercury ototoxicity in mice determined by auditory brainstem responses. Acta Otolaryngol. 99(1-2) 35-45. 

The chronic effect of carbon disulfide exposure on the central nervous system was examined by auditory brainstem responses (ABR) in female JC1 Wistar rats (Hirata et al. 1992b). Rats were exposed by inhalation to 200 or 800 ppm, 6 hours a day, 5 days a week, for 15 weeks. Auditory responses were measured before exposure, every 3 weeks during exposure, and in weeks 2 and 6 after exposure. The... 

Hirata M, Ogawa Y, Okayama A, et al. 1992b. Changes in auditory brainstem response in rats chronically exposed to carbon disulfide. Arch Toxicol 66(5) 344-338. 

Song, Y., O. Ozdamar, and C.C. Lu. 1998. Pasteless electrode/amplifier system for auditory brainstem response (ABR) recording. Annals of Biomedical Engineering. 26, S-103. 

Susceptibility factors Age The effects of chloral hydrate have been studied in an observational study in 1903 infants and young children, 568 of whom were no more than 6 months old, by measuring auditory brainstem responses [22 ]. The sedation rate with a single dose of chloral hydrate 40 mg/kg of 8% was 100% in those under 6 months old, but 28% of the older children needed an additional dose. Adverse events included hyperactivity in 152 children (8%), minor respiratory distress in 10 (0.4%), vomiting in 217 (11.4%), apnea in 4 (0.2%), and a rash in 10 (0.4%). 

Avlonitou E, Balatsouras DC, Margaritis E, Giannakopoulos P, Douniadakis D, Michael T. Use of chloral hydrate as a sedative for auditory brainstem response testing in a pediatric population. Int J Pediatr Otorhinolaryngol 2011 75(6) 760-3. 

EEG response of auditory brainstem responses to sound stimuli allows assessment of the functional level of noncortical areas involved in hearing (Cobo-Lewis and Filers, 2001)... 

Clark considered the notion that hearing, particularly for speech, might be reproduced in people with deafness if the damaged or underdeveloped ear were bypassed and the auditory nerve electrically stimulated, to reproduce the coding of sound. His initial doctoral research at the University of Sydney investigated the effect of the rate of electrical simulation on single cells and groups of cells in the auditory brainstem response, the centre where frequency discrimination is first decoded. 

D. J. Strauss, W. Delb, and P. K. Plinkert (2004) Analysis and detection of binaural interaction in auditory brainstem responses by time-scale representations. Computers in Biology and Medicine 24 461-477. 

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