A Test for the Determination of Sustained Attention in Patients with Obstructive Sleep Apnea Syndrome

Abstract

Background and Objectives: To investigate the parameter daytime sleepiness in patients with the sleep apnea syndrome (SAS), a test for measurement of sustained attention was developed. The present studies were performed on volunteers undergoing preemployment medical examinations and SAS patients to determine the extent to which test results are in agreement with the symptoms of SAS and traffic accident reports, and also with daytime sleepiness, and whether learning or therapeutic effects can be seen with repeated tests prior to and following treatment with nasal continuous positive airway pressure (nCPAP). Methods: Participants: 125 healthy volunteers, and two groups of 28 SAS patients each. Design: Study A: The volunteers underwent a single attention test and completed a questionnaire concerned with traffic accidents and symptoms of sleep-related breathing disorders. Study B: SAS patients underwent two attention tests before treatment. Study C: SAS patients underwent one attention test before and one after nCPAP therapy. Results: Study A: The error rate in volunteers without symptoms of sleep-related breathing disorders (51 persons) was 4.7 ± 4.3% (number of errors 14.1 ± 12.9), 95% CI: 1.2 (number of errors 3.6). No dependence of the error rate on age, BMI or sex was found. In persons with a history of apneic events (n = 10), the error rate was 10.6 ± 10.0% (number of errors 31.8 ± 30), in those with more than two accidents during the last 5 years (n = 4), it was increased to 15.3 ± 9.7% (number of errors 45.9 ± 29.1). Study B: Among SAS patients, no significant learning effect was seen, and prolongation of the test duration beyond 30 min had no effect on the test results. Study C: The error rate improved significantly with nCPAP [10.6 ± 13.5 vs. 6.4 ± 8.9% (number of errors 31.8 ± 40.5 vs. 19.2 ± 26.7), p < 0.001]. Conclusions: The attention test can be helpful for the measurement of daytime sleepiness, and CPAP therapy can improve test performance.