[Clinical diagnoses of pediatric patients without detectable auditory brainstem response (ABR)]

One hundred and forty-seven out of 1,600 infants and children showed no detectable ABR. ABRs were evoked by clicks. As to hearing acuity, 121 out of 147 patients had sensorineural hearing loss and 19 had no hearing impairment of high frequency (3-4 kHz) and high sound intensity (85-90 dBnHL). Eight patients could not be diagnosed whether they had hearing impairment or not. Among 19 patients who did not have sensorineural hearing loss in those ranges described above, 5 patients had cerebral palsy with severe mental retardation, 4 had mitochondrial encephalomyopathy, 3 had degenerative disease of unknown etiology, 2 patients had Down syndrome, 1 was a low birth weight infant with respiratory distress syndrome, 1 was a neonate born to a diabetic mother, 1 experienced severe neonatal asphyxia, 1 patient had acute lymphoblastic leukemia and 1 infant was later confirmed as a healthy girl. Of these, four patients showed transiently negative response in ABR. Nine patients remained undiagnosed as to hearing because they were in deep coma, had profound brain damage, or died in early neonatal period. They had major neurological diseases: severe neonatal asphyxia, holoprocencephaly, microcephaly, degenerative diseases of the central nervous system of unknown origin, metachromatic leukodystrophy, trisomy of chromosome 18, anoxic encephalopathy, small for gestational age newborn with intracranial bleeding and posthemorrhagic hydrocephalus. When ABR cannot be recorded using high sound intensity clicks, it usually suggests presence of hearing impairment of high frequency range. However, there are patients who have no hearing impairment in those sounds.(ABSTRACT TRUNCATED AT 250 WORDS)