CARDIAC VAGAL TONE AND SUSTAINED ATTENTION IN SCHOOL-AGE-CHILDREN

Three hypotheses tested relationships between cardiac responses mediated via the vagus and sustained attention in a population of normal school-age children. These hypotheses addressed the theoretical relationships among resting cardiac vagal tone (using the Forges estimate of respiratory sinus arrhythmia, (V) over cap, performance measures of sustained attention, and cardiac reactivity during sustained attention. Thirty-two fourth and fifth grade children performed a continuous performance task while their electrocardiograms were monitored. Children with higher resting levels of (V) over cap performed better on the first 3-min block of the continuous performance task. Additionally, levels of (V) over cap were significantly reduced across the blocks of the 9-min task for ah children. No relationships were found between resting levels of (V) over cap and change in either (V) over cap or heart period during task performance. These findings support two of the three hypotheses proposed by Forges regarding individual differences in cardiac vagal tone and sustained attention.