title: Iron deficiency anemia in infancy: long-lasting effects on auditory and visual system functioning.
abstract: Evoked potentials provide noninvasive measures of nerve transmission and CNS functioning. Auditory brainstem responses (ABR) and visual evoked potentials (VEP) show dramatic changes in infancy, largely as a result of progressive myelination. Because iron is required for normal myelination, pathway transmission in these sensory systems might be affected by early iron deficiency. We previously reported evidence to that effect: infants with iron-deficiency anemia (IDA) had slower transmission through the auditory brainstem pathway, uncorrected by iron therapy. To determine long-term effects, ABR and/or VEP of healthy Chilean children who were treated for IDA or were nonanemic in infancy were compared at approximately 4 y of age. Absolute latencies for all ABR waves and interpeak latencies (except I-III interval) were significantly longer in former IDA children. Longer latency was also observed for the P100 wave on VEP. The magnitude of differences was large-about 1 SD. These findings, with differences in latencies but not amplitudes, further support the hypothesis that IDA in infancy alters myelination and provide evidence that effects on transmission through the auditory and visual systems can be long lasting. Subtle changes in sensory pathway transmission might be an underlying mechanism for the derailment of other developmental aspects in early IDA.
authors.affiliation: Laboratory of Sleep and Functional Neurobiology, INTA, University of Chile, Chile.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Algarín
authors.forename: Patricio
authors.initials: P
authors.lastname: Peirano
authors.forename: Marcelo
authors.initials: M
authors.lastname: Garrido
authors.forename: Felipe
authors.initials: F
authors.lastname: Pizarro
authors.forename: Betsy
authors.initials: B
authors.lastname: Lozoff
mesh_terms: D018798:Anemia, Iron-Deficiency / Q000188:drug therapy / Q000503:physiopathology* / Q000517:prevention & control; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000187:drug effects / Q000502:physiology; D016057:Evoked Potentials, Auditory, Brain Stem / Q000187:drug effects / Q000502:physiology; D005074:Evoked Potentials, Visual / Q000187:drug effects / Q000502:physiology; D005260:Female; D005296:Ferrous Compounds / Q000627:therapeutic use; D005500:Follow-Up Studies; D005865:Gestational Age; D006801:Humans; D007223:Infant; D008297:Male; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D012016:Reference Values
chemical_list: D005296:Ferrous Compounds; C020748:ferrous sulfate