*Better way to evaluate sleep disorders*

Researchers say the technique is less expensive and invasive than current polysomnography (PSG) technology.

By JUDY SIEGEL-ITZKOVICH
Sleep disorder (photo credit: INGIMAGE)
Sleep disorder
(photo credit: INGIMAGE)
A “groundbreaking approach” approach to determine sleep quality using the innovation of “breath-sound analysis” (BSA) has been developed by Ben-Gurion University of the Negev researchers.
They say the technique less expensive and invasive than current polysomnography (PSG) technology. Their study was published recently in PLOS One Online.
“One of the main goals of sleep medicine today is to improve early diagnosis and treatment of the ‘flood’ of subjects presenting with sleep disorders,” said Prof. Yaniv Zigel, head of the biomedical signal processing research lab in BGU’s biomedical engineering department.
“We’ve developed a non-contact ‘breathing sound analysis’ algorithm that provides a reliable estimation of whole-night sleep evaluation for detection of sleep quality, snoring severity and obstructive sleep apnea [OSA].
It has the potential to reduce the cost and management of sleep disorders compared to PSG, the current standard of treatment, and could be used at home.”
PSG requires a full night’s stay in a sleep center. Subjects are connected to numerous electrodes and sensors that are attached to the patient to acquire signals and data from electroencephalography (EEG), electrooculography (EOG), electromyography (EMG) and electrocardiography (ECG) tests. The data is processed and visually examined or mathematically transformed manually in order to reveal insights about sleep/wake states and many aspects of physiology.
“This procedure is time consuming, tedious and costly due to complexity and the need for technical expertise; the market is begging for a better solution,” said Eliran Dafna, who conducted this study as part of his doctoral research.
In the study, the researchers measured whole-night breathing sounds from 150 patients using both ambient microphones and PSG simultaneously at a sleep laboratory.
The system was trained on 80 subjects and a validation study was blindly performed on the additional 70 subjects. A set of acoustic features quantifying breathing patterns was developed to distinguish between sleep and wake segments. Sleep-quality parameters were calculated based on the sleep/wake classifications and compared with PSG for validity.
When comparing sleep quality parameters, there were only minor average differences in the measurements between PSG and BSA. Measuring 150,000 individual time segments (epochs), the BSA epoch-by-epoch accuracy rate for the validation study was 83.3 percent with 92.2% sensitivity measuring sleep as sleep.
“The results showed that sleep/wake activity and sleep quality parameters can be reliably estimated solely using breathing sound analysis,” said Prof. Ariel Tarasiuk of BGU’s physiology department and head of the sleepwake disorders unit at Soroka University Medical Center.
“This study highlights the potential of this innovative approach to measure sleep in research and clinical circumstances. Clearly, the transition of this technology to at-home sleep evaluation depends on third-party reimbursements for the use of home study equipment.”
ENERGY DRINKS RAISE RESTING BLOOD PRESSURE
Healthy young adults who don’t consume caffeine regularly experienced greater rise in resting blood pressure after consumption of a commercially available energy drink – compared to a placebo drink – thus raising the concern that energy drinks may increase the risk of cardiac events, Mayo Clinic researchers found.
Results of the study will be presented Saturday, March 14, at the American College of Cardiology’s 64th Annual Scientific Session in San Diego.
In this study, researchers alternately gave a can of a commercially available energy drink or a placebo drink to 25 healthy young adults, age 19 to 40, and assessed changes in heart rate and blood pressure. Blood pressure and heart rate were recorded before and 30 minutes after energy drink/placebo drink consumption, and were also compared between caffeine-naïve participants (those consuming less than 160 mg of caffeine per day, the amount frequently found in a cup of coffee) and regular caffeine users (those consuming more than 160 mg of caffeine per day).
Participants experienced a marked rise in blood pressure after consuming the energy drink as compared to the placebo. The effect was most dramatic in people who did not typically consume much caffeine, researchers found. Overall, the blood pressure increase was more than doubled in caffeine naïve adults after consuming the energy drink vs. placebo, they found.
“We know that energy drink consumption is widespread and rising among young people. Concerns about the health safety of energy drinks have been raised. We and others have previously shown that energy drinks increase blood pressure,” says lead author Anna Svatikova, MD, PhD, cardiovascular diseases fellow at the Mayo Clinic. “Now we are seeing that for those not used to caffeine, the concern may be even greater. Consumers should use caution when using energy drinks because they may increase the risk of cardiovascular problems, even among young people.”