We can use pulse oximetry as a method for diagnosis of the sleep apnoea syndrome, as well as L-EKG, MESAM II and the actigraph. In this study MESAM II and pulse oximetry were combined for finding out discrete sleep-related breathing disorders. The results were compared with polysomnography. 5 (15.1%) of 32 patients had an index of apnoea (AI) greater than 10, whereas 4 (12.1%) patients showed an AI greater than 5. All of the patients with positive signs in MESAM II/pulse oximetry had an AI greater than 5 in polysomnography, whereas non of the patients with negative signs in MESAM II/pulse oximetry had an AI greater than 5 in polysomnography.

The pattern of the cyclical variation of heart rate (CVHR) in sleep apnea was described by Guilleminault and coworkers as a characteristic alteration of the respiratory sinus arrhythmia in patients suffering from obstructive sleep apnea (OSA) but with normal autonomic nervous system control. They found that its swings are wider and it does not occur in a cyclical sequence at normal respiratory rate, but in less cycles per time unit and in greater beat-to beat variation in cycle length [1]. There was obviously no significant correlation between the degree of CVHR and clinical variables such as age, weight, and severity of subjective sleepiness or, e.g., oxygen desaturation, the last with an only partly positive correlation.

It is undisputed that nCPAP therapy today is the method of choice for the treatment of sleep apnea (SA) in cases in which general measures such as weight reduction, avoidance of alcohol and sedatives, and sleep position training do not succeed sufficiently. Due to the short- as well as long-term success of nCPAP treatment, without relevant long-term secondary effects, this form of therapy is being increasingly used worldwide. The nCPAP therapy is a symptomatic form of treatment. The reasons for SA are not eliminated, and with the termination of treatment nocturnal cessation of breathing occurs again. A maximal success of treatment can therefore be achieved only by means of a permanent long-term therapy with effective CPAP. Our own experience corresponds to reports in the literature [1, 5] that long-term nCPAP acceptance is dependent basically on long-term care. Besides treating potential secondary effects, regular control measurements are required which can objectify the success of nCPAP therapy.

The high prevalence of sleep-related breathing disorders demands the development of ambulatory recording devices that can handle data with a high degree of selectivity and are easy to use and to interpret. A digital device based on the recording of heart rate and breathing sounds was developed. Patients with sleep-related breathing disorders can be preselected before they undergo sleep laboratory investigations. Treatment control can be achieved ambulatory, having an initial recording.

In view of the high prevalence of sleep apnoea (SA) a stepped concept for diagnosis and therapy is needed. Such a concept requires appropriate instrumentation. The apparative requirement for a five-stage concept, and the experience gained with it, are presented, in particular these newly introduced stages: screening instrument, based on an analysis of heart rate and breathing sounds, and a mobile sleep laboratory based on oxygen saturation measurement combined with inductive plethysmography and four further parameters. Experience obtained with such a stepped concept demonstrates its efficiency and necessity in the diagnosis of sleep-related breathing disturbances.

Sleep apnea and obstructive snoring are sleep related breathing disorders (SRBD). Nevertheless, there is only a quantitative difference between snoring and the obstructive form of sleep apnea. Snoring occurs in at least 20% of the population; 50% of the 50 year old male snore. Although in most of the cases only harmless snoring is concerned. It becomes serious if it leads as the independent SRBD "obstructive snoring" to a continuous oxygen desaturation and a sleep disturbance or, if in cases of sleep apnea a postapnoic snoring is concerned. The snoring pattern "loud and irregular" is always a sign for a serious SRBD. Still, no exact statement can be given concerning the frequency of obstructive snoring. However, the prevalence of sleep apnea in men of the mean age group has been determined to 10%. By the so-called sleep apnea syndrome are summarized clinical pictures with symptoms and findings caused by sleep apnea, respectively with those which can be reduced by sufficiently early introduced therapy. Most frequent symptoms and findings are: hypertension, loud and irregular snoring, daytime sleepiness and nocturnal cardiac arrhythmias. Especially hypersomnia has always to be taken seriously. In relation with other symptoms and findings associated with apnea it is always an indication for the examination for sleep apnea and obstructive snoring.