Repeated measurement of the attention components of patients with multiple sclerosis using the Attention Network Test-Interaction (ANT-I): stability, isolability, robustness, and reliability.

The Attention Network Test (ANT) assesses the networks of attention (alerting, orienting, and executive control). The utility of measuring attention network performances with the repeated administration of the ANT in clinical populations has not yet been explored. In the present study, we administered a variant of the ANT (ANT-I) to 11 multiple sclerosis (MS) patients and 11 controls over six monthly sessions to examine the stability, isolability, robustness, and reliability of the ANT-I. Participants responded through button presses to indicate the direction of a target arrow presented either above or below a fixation cross. The target was accompanied by distracting arrows, pointing either in the same or opposite direction of the target arrow. Target arrows were preceded in some trials by alerting auditory signals and/or by uninformative visual cues. Network scores were calculated using orthogonal subtractions of performance under selected conditions. The MS patients were slower than the controls, though group differences in network performance were rare. Even after five test sessions, the network scores remained stable, despite some practice effects that were the largest under conditions that tested the executive network. The reliabilities of the orienting and executive network effects were good in both groups and increased across sessions, especially with the MS patients. The alerting network was the least reliable, especially for MS patients, but it also became more reliable across sessions. The results suggest that the ANT-I can be used to measure the integrity of attention networks for MS patients in applications that require repeated testing.