Assessing attention: comparison of response-inhibition and traditional continuous performance tests.

The purpose of this study was to compare a recently developed response-inhibition task (Conners, 1995) to slow- and fast-event-rate versions of the traditional A-X Continuous Performance Test (CPT). Among 146 normal adults, results revealed significant differences between tasks in omission and commission error rates, reaction time, reaction time variability, and responses to critical signals. Effects of environmental noise and participant anxiety also differed for the three tasks. Traditional CPTs produced time-related performance decrements, but the response-inhibition task produced improvement across initial blocks of trials. The response-inhibition task may measure "executive control" rather than sustained attention, and therefore may represent functions of different brain systems.

Computerized assessment of sustained attention: a review of factors affecting vigilance performance.

Results of empirical studies using computerized tests of sustained attention are summarized. Factors that affect vigilance performance fall into three broad categories: task parameters, environmental or situational factors, and subject characteristics. Complex interactions of factors from each category affect performance further. Such interactions may help to explain inconsistencies in the literature regarding effects on vigilance. Implications for both research and clinical practice are discussed.

Computerized assessment of sustained attention: interactive effects of task demand, noise, and anxiety.

In a sample of 163 college undergraduates, the effects of task demand, noise, and anxiety on Continuous Performance Test (CPT) errors were evaluated with multiple regression and multivariate analysis of variance. Results indicated significantly more omission errors on the difficult task. Complex interaction effects of noise and self-reported anxiety yielded more omissions in quiet intermittent white noise, particularly for high-anxious subjects performing the difficult task. Anxiety levels tended to increase from pretest to posttest, particularly for low-anxious subjects in the quiet, difficult-task condition, while a decrease was seen for high-anxious subjects in the loud, easy-task condition. Commission errors were unrelated to any predictor variables, suggesting that "attention" cannot be considered a unitary phenomenon. The variety of direct and interactive effects on vigilance performance underscore the need for clinicians to use a variety of measures to assess attentional skills, to avoid diagnosis of attention deficits on the basis of a single computerized task performance, and to rule out anxiety and other contributors to poor vigilance task performance.