Using information hidden in the beat-to-beat changes of the heart's electrical signals, researchers at Beth Israel Deaconess Medical Center (BIDMC) have developed an inexpensive method to assess the stability and quality of sleep, which could be used to help understand the mechanisms of sleep control and diagnose sleep disorders, as well as to test the efficacy of sleep aids and other medications.
Known as a "sleep spectrogram," the novel graph is based on data obtained solely from a simple electrocardiogram (ECG). The spectrogram is described in a study in the Sept. 1 issue of the medical journal Sleep, which currently appears on-line.
"This new ECG-based approach is important because it promises to provide an affordable and readily achievable way to monitor sleep stability in a wide range of conditions, including sleep apnea, depression, fibromyalgia, heart failure and stress," explains cardiologist Ary Goldberger, MD, Director of the Margret & H.A. Rey Institute for Nonlinear Dynamics in Medicine and the study's senior author.
The new study, led by sleep researcher Robert Thomas, MD, of BIDMC's Division of Pulmonary, Critical Care and Sleep Medicine, identified two distinct types of behavior exhibited throughout the course of a person's sleep, the first being stable and restful, the second being unstable and aroused. The results show that conventional approaches to categorize non-REM (non-rapid-eye-movement) sleep into grades of depth do not capture this potentially important dimension.