[Multiple sleep latency test in patients with obstructive snoring]

The objective of our study was to examine the effect of the n-CPAP on day tiredness of patients suffering from obstructive snoring. This effect was objectified by means of the Multiple Sleep Latency Test (MSLT). The MSLT was performed with optimal pressure at 8.00, 10.00, 12.00 and 14.00 hrs. subsequent to the control night and the third CPAP night. The latencies of falling asleep and the sleep stages were determined in accordance with the criteria of Rechtschaffen and Kales. The average latency of falling asleep before therapy was: at 8.00 hrs 9.0 +/- 14.2 min, at 14.00 hrs. 7.2 +/- 6.3 min. The following latencies of falling asleep were observed after the third CPAP night: 8.00 hrs. 14.2 +/- 6.3, 10.00 hrs. 13.4 +/- 6.4, 12.00 hrs. 13.7 +/- 6.4 hrs. 13.7 +/- 6.0 min. This means that after the therapy there was a marked tendency to longer latencies at all 4 points of measurement with significant differences at 12.00 and 14.00 hrs. A comparison of the quality of sleep before and after the therapy yielded an increase in deep sleep and a significant increase in REM density during dream sleep. MSLT enabled objectivation of improved sleep quality and of subjective decrease in day tiredness after CPAP therapy in patients with obstructive snoring. The latency in falling asleep increased at all the points of measurement. Nevertheless, interindividual differences are great, compared with the uniform subjective success of CPAP therapy achieved with these patients.