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Biomedical subjects

L S Mencher

Publications and source records attributed to L S Mencher.

5 recordsLinked to original sources

Recent changes in the etiology of hearing disorders: perinatal drug exposure.

In recent years, we have observed causes of congenital or early onset hearing disorders that had not been recognized or known to exist before. These include drugs passed to an as-yet unborn child. Principal among them is alcohol, but others, such as cocaine, are now also occupying our attention. This article reviews the effects of such exposure on the communication skills of children who had been exposed. It is not yet clear whether there are specifically auditory effects, nor is it clear whether the communicative effects are long lasting.

Cocaine↗

Auditory brain stem responses to air- and bone-conducted clicks in the audiological assessment of at-risk infants.

Auditory brain stem responses (ABRs) to air- and bone-conducted clicks were used to assess the auditory status of 170 at-risk neonates. During the perinatal period, 20.6% (35/170 cases) of the at-risk infants failed ABRs to air-conducted clicks at 30 dB nHL in at least one ear. Ear-specific results indicated an initial failure rate of 15.0% (51/340 ears). Approximately two-thirds (32/51 ears) of these initial failures showed purely conductive deficits, whereas the remaining one-third (19/51 ears) involved suspected sensorineural components. Follow-up audiological evaluations were performed for 87.1% (148 cases) of these at-risk infants at 4 mo and/or 1 yr corrected age. Based on the initial tests and follow-up assessments, the tentative operating characteristics of ABRs to both air- and bone-conducted clicks for identification of sensorineural deficits in at-risk neonates were calculated. It was found that the ABR to bone-conducted clicks yielded better specificity, predictive value of positive results, and overall efficiency. It is suggested that the ABR to bone-conducted stimuli should be viewed as a valuable addition in the assessment of cochlear reserve in infants who fail a newborn auditory screening to air-conducted stimuli.

Acoustic Stimulation↗

Maturation of behavioral response.

The level of maturation of the auditory system markedly affects the results of all forms of infant hearing screening. The same test repeated in two weeks may yield significantly different results. The paper reviews some of the maturational changes which occur, considers male/female differences, and offers some normative developmental information about the preterm infant.

Audiometry↗

Neonatal asphyxia, definitive markers and hearing loss.

A study of 56 severely asphyxiated infants (8 hearing impaired and 46 normally hearing) was designed to identify specific markers associated with asphyxia which could be related to hearing loss. Sixteen variables, including such items as: one- and five-minute Apgar scores, muscle tone, use of a ventilator, prolonged stay in the NICU, hypoxic-ischemic encephalopathy (HIE), other organ damage, and intra-uterine growth retardation (IUGR) were considered. Results suggested four factors related to asphyxia which are often found in the presence of hearing loss, but none of these was considered a definitive marker or predictor of such a disability. A combination of HIE, seizures, associated organ damage and IUGR should be considered a strong marker for the probability of a sensorineural hearing loss.

Apgar Score↗