It would stand to reason that tests designed to monitor a patient's sleep would be comfortable, wouldn't it? But unfortunately that's not quite the case, especially when patients are monitored for sleep apnea.

Instead, nearly 20 electrodes are placed down the patient's throat and a large array of sensors is placed on the patient's body. It's not exactly conducive to a good night's rest according to some researchers, which has led to a study looking for an alternative means in testing for sleep apnea.

Researchers at the University of Houston (UH) and University of Texas Health Science Center (UTHSC; Houston) have tested a new method of detecting sleep apnea and hypopnea from a distance, using thermal infrared imaging (TIRI).

Researchers say that the method is capable of extracting breathing waveforms and monitoring airflow. This study is the first of its kind to diagnose sleep apnea using noncontact technology.

The findings were published in this month's issue of the journal Sleep.

"The results of the study is basically in a nutshell that now we can measure breathing function using passive imaging and computation without any need to use probes and cables in the throat," said Ioannis Pavlidis, Eckhard-Pfeiffer Professor of Computer Science at the University of Houston during a press conference. "And that's a huge relief for a long monitoring period during a particular subtle situation such as sleep in a lot of patients."

Nearly 24% of men and 9% of women experience sleep apnea, but getting a diagnosis involves a procedure called polysomnography, also known as a sleep study. The study can be cumbersome and interrupt sleeping functions.

"It's not as simple as paying a visit to the doctor in the morning for an hour and walking away with a prescription," said, Jayasimha Murthy, assistant professor of medicine from the Division of Pulmonary Critical Care Sleep Medicine at UTHSC at Houston and co-investigator of the study. "You have to undergo overnight monitoring in a sleep lab. The subject is wired and sleeps there. Sometimes, the subject has to spend more than one night."

The new diagnostic procedure developed by Pavlidis, Murthy and their collaborators uses a thermal infrared camera to monitor breathing waveforms and airflow as a patient breathes in and out of his or her nose. The measurements are processed using computational algorithms and produce results that have proved to be as accurate as traditional polysomnography.

The new method also provides doctors with more information about the patient's breathing.

"In contrast to the traditional one-dimensional methods, this new method is an imaging one and thus, multi-dimensional," said Pavlidis. "We now can see how airflow is distributed locally throughout the extent of the nostril. We get not a single, but multiple values for each nostril at every point in time and this makes a lot of difference when it comes to appreciating subtle pathology."

The researchers said that they believe that this new technology could change the way sleep apnea is diagnosed, potentially helping millions of Americans sleep better and possibly live longer.

From here the researchers will take a two step approach toward continuing to push for more studies to prove the efficacy of this procedure.

"On the medical level we still have to show this technology is as good as conventional tests in overnight studies," Murthy said.

He added that the pilot study only tested patients for a two-hour-period.

On the scientific level Pavlidis said there still needs to be additional studies testing the patient's breathing. He noted that there is still a lot more that can be done with this method.

"The next step on the scientific level is to push more toward the multi-dimensional investigation particularly of airflow and not just [limit] ourselves with reproducing the same results as the conventional sensors," Pavlidis said.

Omar Ford, 404-262-5546;
omar.ford@ahcmedia.com