Time Clustering of the Occurrence of Sleep Apnea

Problem statement: In this study, the inequality of apnea rates during sleep was investigated. Approach: This study used a database comprising 13 patients with apnea problems. The data was extracted from the MIT-BIH database. The Lorenz curve and Gini index were used to determine the inequality of apnea rates. In order to test for cluster, random or regular patterns of apnea, an index of runs was used. Results: The Lorenz curve showed that the distribution of apnea events for every 10% period of sleep varied between each patient. The Gini index ranged between 0.148 and 0.614. Most of the patients had a Gini coefficient lower than 0.5. The index of runs was between 0.115 and 0.353, which indicates that most patients had a regular pattern of apnea and that it is not random. Conclusion: The distribution of the apnea is almost equal and most patients have regular patterns of occurrence of apnea.