Association of hemoglobin levels and brainstem auditory evoked responses in lead-exposed children

Objectives: Decreased blood hemoglobin (HbB) levels and anemia have been associated with abnormal brainstem auditory evoked responses (BAER). Lead (Pb) exposure has also been associated with anemia and aberrant BAER. This study investigated the relationship between HbB level and BAER wave latency and amplitude in Pb-exposed Andean children. Design and methods: Sixty-six children aged 2 to 15 years (mean age: 9.1; SD: 3.3) living in Pb-contaminated villages were screened for HbB levels, blood Pb (PbB) levels and BAER latencies and amplitudes. Results: The mean HbB level observed in the study group was 11.9. g/dL (SD: 1.4; range: 8.6-14.8. g/dL). The mean HbB level corrected for altitude was 10.3. g/dL (SD: 1.4; range: 6.9-13.1. g/dL), and suggestive of anemia. The mean PbB level was 49.3. μg/dL (SD: 30.1; range: 4.4-119.1. μg/dL) and indicative of Pb poisoning. Spearman rho correlation analyses revealed significant associations between the BAER absolute latencies and HbB level, indicating that as the HbB level decreased, the BAER wave latency increased. Children with low HbB levels (≤ 11 g/dL) showed significantly prolonged absolute latencies of waves I, II, III, IV and V compared to the children with normal HbB levels. Although a significant relationship between HbB and BAER waves was observed, no significant associations between PbB level and BAER parameters were found. Conclusion: Low hemoglobin levels may diminish auditory sensory-neural function, and is therefore an important variable to consider when assessing BAER in children with anemia and/or Pb exposure.