A low cost screening test for Obstructive Sleep Apnea that can be performed at the patient´s home

This paper presents a new screening test for Obstructive Sleep Apnea-Hypopnea (OSAH) Syndrome based on a PDA platform capable of recording the patient´s electrocardiogram during his/her nightly rest. OSAH patients present alterations in certain bands of the heart rate variability power spectrum. The more serious the disorder afflicting the patient it is, the greater these alterations are. An algorithm running on the PDA identifies the heart beats, and it calculates the RR intervals time series. Then the algorithm calculates an index that quantifies the magnitude of the heart rate variability power spectrum alterations, and therefore the severity of the patient´s condition. The reliability of this index has been validated using the Apnea-ECG Database. After the first night of use of the device at the patient´s home, the PDA communicates the test results to the hospital via the Internet using a WiFi connection, or through GPRS/UMTS. In the hospital, the physicians can decide whether the results are conclusive, or whether it is preferable to repeat the test. Sometimes it may be necessary to repeat the test just because one of the sensors of the electrocardiograph was disconnected during the night. This decision is communicated through the PDA to the patient, who then knows whether he/she should return the device, or if he/she should use it again the following night. The end result is a cheap and reliable OSAH screening test that neither involves a long waiting list nor requires an overnight stay in the hospital for a polysomnographic test.