Effects of iron-deficiency anemia on auditory function in school-aged children

Abstract

Introduction Iron is important for proper myelination of spinal cord and white matter of cerebellar folds in brain and is a cofactor for a number of enzymes involved in neurotransmitter synthesis. Auditory brainstem evoked response (ABR) represents the progressive activation of different levels of the auditory pathway from the acoustic nerve (wave I) to the lateral lemniscuses (wave V). Otoacoustic emissions (OAEs) are sounds measured in the external ear canal that reflect movement of the outer hair cells in the cochlea. Patients and methods A total of 40 children, of both sexes, with age ranging from 6–12 years old, were selected for this study after a thorough clinical assessment to exclude any other pathological disorder other than anemia. They are compared with a control group that consisted of 20 normal children of the same age. After laboratory investigations, all children were examined by ABR and transient-evoked OAEs. The study group children were classified according to ABR results into study group 1, comprising anemic children with abnormal ABR results and study group 2, comprising anemic children with normal ABR results. Results ABR showed that absolute peak latencies of waves I, III, and V and interpeak latencies were prolonged; moreover, ABR waves I and V showed reduced amplitude in study group 1 than control group, and the difference is statistically significant. In contrast, there was no statistically significant difference between study group 2 and control group regarding ABR results. Transient-evoked OAEs results showed no statistically significant difference between anemic children and control group. Conclusion This study added to the evidences that iron-deficiency anemia is a risk factor for auditory function impairment. Further studies for the effect of timing, duration, and severity of iron deficiency on auditory functions are needed. Well-designed large-scale studies are needed to address the iron-deficiency anemia in health planning programs to put plans for control and prevention especially in developing countries.

Keywords

• auditory brainstem evoked response
• iron
• otoacoustic emissions
• inter-peak latencies