NORMAL AUDITORY BRAIN-STEM AND COCHLEAR FUNCTION IN EXTREME PEDIATRICPLUMBISM

Lead (Pb) intoxication in children has been associated with encephalop athy, sensory and cognitive impairments. We investigated the prevalenc e and neuro-sensory effects of Pb exposure in children living in Andea n villages of Ecuador with high Pb contamination from discarded automo bile batteries used in the local ceramics glazing industry. Venous blo od samples were collected from 107 children in the Pb glazing area and from 39 children living in a geographically distant area with no know n Pb contamination and measured for blood lead (PbB) levels. Auditory brainstem responses (ABR) and audiological/otological tests were condu cted on children in the Pb-Glazing Group. The median PbB level for chi ldren in the Pb-Glazing Group was 40.0 mu g per dl (range: 6.2-128.2 m u g per dl) and for the non Pb-Glazing Group 6.0 mu g per dl (1.9-18.0 mu g per dl). The differences in PbB levels for children in the study and control areas were statistically significant (t-test, P<0.0001). ABR tests on the Ph-Glazing Group indicated normal wave latencies and neural transmission times, and no statistical correlation between WE l evel and interpeak latencies. Audiological tests showed normal cochlea r function and no statistical relation between auditory thresholds and PbB level. Contrary to prevailing assumptions, elevated PbB levels in children do not invariably impair auditory brainstem neural transmiss ion or sensory-neural cochlear function, both of which have been impli cated as significant contributors to the neurodevelopmental disabiliti es associated with childhood plumbism. (C) 1997 Elsevier Science B.V.