The strength of the present study is the length of
follow up of 16 weeks. Previous studies have followed
patients for only 8 weeks [10–15]. Another
finding of importance was the high adherence to treatment in the study. Only one patient dropped
out after randomization. We found that all of the
patients followed the instructions thoroughly and
reported that they used the Resperate and CDplayer
at least 3 times a week during 15 min sessions.