Auditory function

Suggestive evidence of a lead-related decrease in hearing acuity in children has been reported by Robinson et al. (1985) and Schwartz and Otto (1987, 1991). Hearing thresholds at 2,000 Hertz increased linearly with maximum blood lead levels, indicating that lead adversely affects auditory function. The PbB levels in 75 asymptomatic black children, 3-7 years old, ranged from 6 to 59 tg/dL (mean,... 

Wu, M-F., J.R. Ison, J.R. Wecker, and L.W. Lapham. 1985. Cutaneous and auditory function in rats following methyl mercury poisoning. Toxicol. Appl. Pharmacol. 79 377-388. 

The mechanosensory systems of fish, including the lateral line, are closely related to the mammalian hearing system [12]. Besides possessing the typical vertebrate inner ear, fish possess the lateral line organs that contain sensory hair cells. These analogies are most relevant in toxicology and dmg discovery and evaluation, as some of the pharmaceuticals already detected in aquatic ecosystems as emerging pollutants affect the auditory function in humans. 

A major clinical distinction between the effects on the inner ear and the kidney is the fact that the renal effects are reversible while the effects on the inner ear are irreversible, leading to permanent loss of balance or auditory function. Furthermore, renal insults can more easily be monitored and thereby largely prevented, while monitoring of impending auditory or vestibular damage is not always possible. Ototoxic side effects frequently develop after cessation of aminoglycoside treatment, sometimes delayed by weeks. This review will therefore focus on the ototoxic side effects as a major unresolved issue in aminoglycoside toxicity. 

Auditory effects Perform periodic auditory function tests during chronic fenoprofen therapy in patients with impaired hearing. 

Monitoring Perform auditory function serial tests and monitor serum levels. When monitoring vancomycin serum levels, draw a peak concentration 1.5 to 2.5 hours after the completion of a 1-hour infusion and a trough concentration within 1 hour of the next scheduled dose. Peak levels are generally expected to be in the 30 to 40 mg/mL range and trough levels in the 10 to 15 mg/mL range. 

All members of the neomycin group have significant nephrotoxicity and ototoxicity. Auditory function is affected more than vestibular function. Deafness has occurred, especially in adults with impaired renal function and prolonged elevation of drug levels. 

Yin, T.C.T. and Chan, J.C.K. (1988) Neural mechanisms underlie interaural time sensitivity to tones and noise. In W.E. Gall, G.M. Edelman, and W.M. Cowans (Eds.), Auditory Function Neurobiological Bases of Hearing. Wiley, pp. 385 130. 

The effect of THC, 7.5 mg and 15 mg, on auditory functioning has been investigated in eight men in a doubleblind, randomized, placebo-controlled, crossover trial (97). Blood concentrations of THC were measured for up to 48 hours after ingestion, and audiometric tests were carried out at 2 hours. There were no significant differences across treatments, suggesting that cannabis does not affect the basic unit of auditory perception. 

LOOP DIURETICS CISPLATIN t risk of auditory toxic effects with cisplatin Loop diuretics cause tinnitus and deafness as side-effects. Additive toxic effects on auditory system likely Monitor hearing - test auditory function regularly, particularly if patients report symptoms such as tinnitus or impaired hearing... 

The same spectrum of toxicity (ototoxicity and nephrotoxicity) is shared by all members of the group, The more important and frequent interactions are pharmacodynamic. Streptomycin and gentamicin produce predominantly vestibular effects, whereas amikacin, kanamycin and neomycin primarily affect auditory function. All are rapidly excreted by the kidney,... 

Serious adverse effects of aminobisphosphonates were reported in otospongiosis. Of two patients with stapedial otosclerosis and sensorineural hearing loss one developed total bilateral deafness and the other retained minimal auditory function in the low frequencies (25). It was recommended that sensorineural deafness in selected patients with otosclerosis should be treated with sodium fluoride, and that patients with Paget s disease treated with aminobisphosphonates should be closely monitored and the drug discontinued immediately if hearing deteriorates. Elsewhere, ototoxicity has been reported (SEDA-20, 440). 

Burbacher, T.M., K.S. Grant, S.G. Gilbert, and D.C. Rice. 1999. TTie effects of methylmercury exposure on visual and auditory functions in nonhuman primates. Toxicologist 48(1-S) 362. 

C) Maintain the patient on the present dosage and test auditory function... 

Otto D, Hudnell K, Boyes W. 1988. Electrophysiological measures of visual and auditory function as indices of neurotoxicity. Toxicology 49 205-218. 

ToUin D.J. and Yin T.C.T (2001). Investigation of spatial location coding in the lateral superior olive using virtual space stimulation. In Physiological and Psychophysical Bases of Auditory Function. Houtsma A.J.M., Kohhausch A., Prijs V.F., and Schoonhoven R. (Eds.), Maastricht Shaker Publishing, pp. 236-243. 

R. Hebert, J.M. Langlois and J.H. Dussault, Permanent defects in rat peripheral auditory function following perinatal hypothyroidism determination of a critical period, Dev. Brain Res. 23 161-170 (1985). 

The coimnittee concludes that the evidence is sufficient to infer causal relationships between BLLs under 40 pg/dL and adverse effects on nervous system function (see Table 4-1). Effects on both the central and peripheral nervous systems have been observed, including effects on cognitive fmction, peripheral nerve function, visual and auditory function, posture and balance, and autonomic nervous system function. 

Instruments that could be used to evaluate infant sensory competencies in studies on the developmental effects of adding new ingredients to infant formulas are shown in Table 6-11. Even though the instruments described in the table have not been specifically linked to CNS development, sensory functions tapped by these instruments clearly have specific associations with brain structure and function. While preferential-looking procedures to test visual function and visual reinforcement audiometry to test auditory function have not been used in studies with infants exposed to toxins, they have been extensively used in clinical studies. These two procedures are thus recommended as being state of the art in the behavioral assessment of visual and auditory function. They could be easily combined with the func-... 

Tests of auditory function Visual reinforcement audiometry, where the child s head turning toward different sounds at different frequency levels are reinforced by an interesting visual stimulus (Moore et al., 1977)... 

As seen in the overview of the proposed clinical guidelines (Figures D-4, D-5, and D-6), it is not clear whether assessments of body composition, immune response, auditory function, and temperament were conducted. Several of these tests (to be determined by expert panels), applied at level 2 or level 3, are especially important to determine the safety of LC-PUFAs because theoretical safety concerns exist. For example, LC-PUFAs affect immune response, and they have been linked to neural development. Chapter 6 provides the committee s findings and recommendations on body composition and immune, auditory, and temperament assessment. 

Special ocular and auditory functions that address specific pharmacological or chemical class issues... 

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