Original Article Neurocognitive function in patients with b-thalassemia major Ozgur Duman, 1 Sema Arayici, 2 Cigil Fettahoglu, 3 Nurkan Eryilmaz, 3 Sibel Ozkaynak, 4 Akif Yesilipek 2 and Volkan Hazar 2 Departments of 1 Pediatric Neurology, 2 Pediatric Hematology and Oncology and Bone Marrow Transplant Unit, 3 Child and Adolescent Psychiatry and 4 Neurology, Faculty of Medicine, Akdeniz University, Antalya, Turkey Abstract Background: Children with b-thalassemia major (b-TM) have multiple risk factors for developing cognitive impair- ment. The aim of the present study was to evaluate cognitive function in patients with b-TM. Methods: Twenty children with b-TM were enrolled into the study and were compared with a control group consisting of 21 healthy children. All participants were evaluated with neuropsychological tests and event-related potentials (ERP). Results: All of the participants had normal IQ scores, but the patient group had significantly lower full-scale, perfor- mance, and verbal IQs compared with the control group (P < 0.05). The number of children with visuomotor dysfunction was higher in the patient group compared with the control group (P < 0.05). In the P300 test, the patient group had significantly prolonged N1, P2 and N2 latencies at the FZ, and a prolonged N1 latency at the Cz compared with the control group (P < 0.05). The patient group also had lower N1 and P3N4 amplitudes at the Fz, and lower N1, N1P2 and P3N4 amplitudes at the Cz when compared with the control group (P < 0.05). Mismatch negativity latency and duration were longer in the patient group (P < 0.05). Conclusions: Neuropsychological tests are safe, and reliable for the diagnosis of cognitive impairment in b-TM patients, and the use of ERP may facilitate early diagnosis. The number of b-TM patients in the present study was limited, however, and larger numbers of patients are required in further studies. Key words anemia, b-thalassemia, cognition, mismatch negativity, P300. Thalassemias are the most common single-gene diseases world- wide. Thalassemias are caused by defects in the production of globin chains, which combine to form hemoglobin. 1,2 Children with b-thalassemia major (b-TM) develop anemia that progres- sively becomes worse due to the partial or total absence of hemo- globin. The life expectancy of children with b-TM is increased with transfusion, chelation therapy and bone marrow transplan- tation. In these patients, complications are generally associated with iron deposition resulting from frequent blood transfusions, hemolysis, and increased intestinal iron absorption, and thus pose a risk for parenchymal organ injuries. 3,4 Iron deposition mainly affects the liver, heart, pancreas, gonads, parathyroid and thyroid glands, bones, lungs, peripheral and central nervous systems (CNS). CNS complications generally present as cognitive dys- function, which usually results from iron deposition and neuro- toxicity of deferoxamine (DFO), which is commonly used as a chelating agent. 5–7 Furthermore, hypoxemia and thromboemboli may cause CNS complications and cognitive dysfunction. 4,8 The side-effects due to the disease itself or its treatment, being unable to attend school, frequent hospitalizations, and the physical and social restrictions as a consequence of chronic disease and its treatment also lead to cognitive dysfunction. 9 Event-related potentials (ERP) provide a measure of infor- mation processing. P300 and mismatch negativity (MMN) are well-known endogenous potentials that have been used in the assessment of cognitive function in several disorders, including anemia. 10–13 Both P300 and MMN are elicited by an infrequent perceptible change in a repetitive stimulation. The former is thought to represent a neurophysiological index of auditory infor- mation processing, which is dependent on attention, whereas the latter is considered to be an index of pre-attentive processing that is independent of attention. 14,15 Limited studies have evaluated cognitive function in patients with b-TM and the results are conflicting. 16–20 The aim of the present study was therefore to investigate neurocognitive impair- ment in patients with b-TM through electrophysiological (MMN and P300) and neuropsychological testing. Methods Subjects Twenty right-handed children with b-TM (11 boys, nine girls; mean age, 9.2 1 2.4 years; range, 7.0–15.1 years), who had normal auditory test results and no neurological complaints, thyroid hormone dysfunction, or vitamin B12 deficiency were enrolled into the study and were compared with a control group consisting of 21 healthy right-handed children (11 boys, 10 girls; Correspondence: Volkan Hazar, MD, Akdeniz University Faculty of Medicine, Department of Pediatric Hematology and Oncology and Bone Marrow Transplant Unit, 07070 Antalya, Turkey. Email: hazar@ akdeniz.edu.tr Received 23 July 2009; revised 19 August 2010; accepted 7 October 2010. Pediatrics International (2011) 53, 519–523 doi: 10.1111/j.1442-200X.2010.03279.x © 2011 The Authors Pediatrics International © 2011 Japan Pediatric Society