Sleep apnea syndrom and symptom biofeedback - A contolled single-case-study

Background: The sleep apnoea syndrome (SAS) is a respiratory disease that o ccurs during sleep and is characterized by 10 or more apneas per hour, whic h last longer than 10 seconds. Among the chief complaints are daytime sleep iness and exhaustion. Male sex and obesity are risk factors for this disord er that leads to heart diseases and increased mortality. SAS is mainly trea ted by mask-induced nasal continuous positive airway pressure (nCPAP), whic h often is annoying to patients. In the face of this unsatisfactory medical treatment, we developed a sleep apnoea feedback training (SAF), that conti ngently provides the patient with feedback of apneas. Method: Using a two-s tep-feedback of respiration during sleep, measured by temperature of breath , the patient has to learn to shorten or prevent apneas. We expected a cond itioning process to occur, following the paradigm of avoidance learning, SA F underwent a first test in a single case study with an A-B-A-B-A-design (A -phases: baseline measurement, B-phases: treatment). The participant, a 58- year-old mechanic, had had respiration problems during sleep for 10 years. In the beginning of the study he showed an apnoea-hypopnoea-index of 36/h. Results: Unexpectedly, SAF did not substantially influence the length of re spiration breaks. The number of breaks, however, decreased by about 40%. Th is reduction continued up to the last A-phase. Moreover, a specific effect of learning occurred: During the SAF nights, but not during the nights with out feedback, the number of respiration breaks decreased with increasing sl eep duration. Discussion: Thus, it appears useful to further develop SAF an d to compare its effectiveness with nCPAP.