title: The Effects of Six-Month L-Thyroxine Treatment on Cognitive Functions and Event-Related Brain Potentials in Children with Subclinical Hypothyroidism.
abstract: OBJECTIVE
  The aim of this study was to investigate the cognitive status of children with subclinical hypothyroidism (SH) before and after L-thyroxine (L-T4) treatment using event-related potentials (ERPs) and neuropsychological tests.
  
  
  METHODS
  This prospective study was conducted on a series of 20 children with mild SH (free T4 normal and thyroid-stimulating hormone level within 5-10 µIU/L) who underwent clinical and cognitive assessment before L-T4 treatment and 6 months afterwards. The recordings of ERPs were done at the time of diagnosis and after 6 months of euthyroid state. Neuropsychiatric tests for attention, perception, close and remote memory were performed on all patients and on the control group which consisted of 20 healthy children of normal intelligence.
  
  
  RESULTS
  While pretreatment verbal memory (VM) and verbal recall (VR) scores of the SH group were significantly lower than those of the control group (p=0.004 and 0.012, respectively), no significant differences between the post-treatment and control groups were found in these scores after 6 months of L-T4 treatment. Post-treatment VM and VR scores were significantly higher than the pretreatment scores in the SH group (p=0.008 and p=0.0001). There were no significant differences between the pre-and post-treatment values of electrophysiological evaluation in N1, P2, P3 latencies or P3 amplitude (p>0.05), although there was a significant decrease in N2 latency in the post-treatment group (p=0.03).
  
  
  CONCLUSIONS
  SH affects cognition in children and L-T4 replacement therapy leads to normalization of cognitive functions. Neuropsychological tests can be used as complementary measures in the evaluation of children with SH. Determining the association between ERPs and SH would contribute to the comprehensive evaluation of these children.
authors: Özlem
authors: Ö
authors: Sangün
authors: Serpil
authors: S
authors: Demirci
authors: Nihal
authors: N
authors: Dündar
authors: Özgür
authors: Ö
authors: Pirgon
authors: Tuğba
authors: T
authors: Koca
authors: Melike
authors: M
authors: Doğan
authors: Katip Çelebi University Faculty of Medicine, Department of Pediatric Endocrinology, İzmir, Turkey Phone: +90 232 329 35 35 E-mail: bumindundar@gmail.com.
authors: Bumin
authors: B
authors: Dündar
mesh_terms: D000293:Adolescent; D001288:Attention / Q000187:drug effects; D002648:Child; D002675:Child, Preschool; D003071:Cognition / Q000187:drug effects*; D004569:Electroencephalography; D005071:Evoked Potentials / Q000187:drug effects*; D005072:Evoked Potentials, Auditory / Q000187:drug effects; D005260:Female; D020249:Hormone Replacement Therapy; D006801:Humans; D007037:Hypothyroidism / Q000188:drug therapy* / Q000523:psychology*; D008297:Male; D008568:Memory / Q000187:drug effects; D009483:Neuropsychological Tests; D010465:Perception / Q000187:drug effects; D011446:Prospective Studies; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000627:therapeutic use*
chemical_list: D013972:Thyrotropin; D013974:Thyroxine