Executive function and neural activation in adults with β-thalassemia major: an event-related potentials study

In recent years, there has been growing interest in understanding the involvement of the nervous system and neurological complications in beta-thalassemia major (beta-TM). Several reports have demonstrated beta-TM-related neurological abnormalities, and these have been postulated to be responsible for impaired cognitive and neuropsychological functioning. We investigated neural correlates of cognitive function in adults with beta-TM and healthy controls using scalp-recorded event-related potentials (ERPs). To date, there have been no ERP studies in beta-TM adult patients. We identified ERP correlates of executive function by using a complex task-switching paradigm in which participants have to quickly and effectively switch between two different task sets. The results indicated poorer cognitive performance of beta-TM patients, resulting in overall higher error rates, longer response times, and increased switch costs compared with controls. Hemoglobin levels were negatively correlated with error rates and response times. Electrophysiological results indicated significant alterations in peak amplitudes of the ERP components P1, N1, and P2 in beta-TM patients relative to controls. P2 amplitude correlated with hemoglobin levels. This novel investigation of executive function and related brain mechanisms and dynamics in adults with beta-TM underscores the usefulness of ERP methodology as a sensitive measure for the study of neurocognitive processes in beta-TM.