The Application of Time-Series Analysis to the Diagnosis of Complex Internal Disorders: Sleep Apnea

Abstract

Clinical pictures in internal medicine are usually defined in terms of threshold values of certain specific parameters. Hypertension, for instance, is defined as a systolic arterial blood pressure in excess of 140 mmHg or a diastolic reading of more than 95 mmHg. Complex clinical pictures such as sleep apnea cannot be adequately described in this way, however, as they involve a large variety of interrelated parameters whose development has to be evaluated over a longer period of time. As far as ECG parameters are concerned, such monitoring has long been practised in intensive care units. In complex disorders, though, parameters of a widely different nature have to be taken into account and interpreted in a comprehensive approach. A systematic comparison of, for example, ECG, EEG, blood pressure, and various respiratory parameters is not easily accomplished. It is here that the methods of time-series analysis become indispensable [1].