Not long ago, sleep technologists spent hours reviewing a patient's video sleep study, playing and reversing a tape to correlate patient movements and sounds with specific apneic events. Clunky old video tapes no longer line shelves in many of the nation's sleep centers.

Today, most full polysomnography systems synchronize digital video recorders with EEG signals to correlate patient behavior with sleep abnormalities such as nocturnal seizure disorders. The clinical utility of digital PSG recording for adult and pediatric patients is increasing as technology has become more portable, efficient, and data storage less cumbersome.

Portable video PSG systems allow technologists to view patient waveform data and video in real time from remote locations.

From miles away, technologists can zoom, pan, and tilt the infared camera to best capture the patient's sleeping behavior at home, in a hospital, or in a long-term care facility. "It's like being in a sleep lab," said Deb Jokinen, RPSGT, a sleep technologist who has spent 25 years in the field. "The data being collected is identical, without the discomfort that many patients experience of sleeping in an unfamiliar environment."

High resolution, frame rate, and sound quality enable technologists to capture patient movements and vocalizations like chest wall excursions that could differentiate between central apnea, hypoventilation, or obstructive apnea. Equally important is software to support easy scoring, review, and annotation of the continuous audio and video recording. Systems with mobile phone broadband internet service now allow technologists to monitor patients anywhere there is a phone signal. These devices' internal memory stores patient data internally to prevent recordings from being lost if internet coverage is irregular.

When choosing a portable PSG system, sleep centers should look for a system that combines patient comfort with these state of the art video technologies. Some systems integrate the headbox, amplifiers, transducers, and data telemetry into one wireless handheld unit so patients do not disconnect wires if they move from their bed during the study.

"This technology is the wave of the future," Jokinen said. "But for any lab that wants to do this, it has to be well thought through, and it has to be quality driven."

For example, a team of technologists could set up patients in their homes. The first technologist could obtain consent forms, educate and instruct the patient about their sleep study, apply electrodes, and verify their integrity. Before he leaves the patient's home, the monitoring technologist could connect remotely to the portable system and begin initial calibrations to ensure the equipment is working properly.

Studies performed remotely where the technologist can not intervene in person if an issue arises with a patient receive lesser reimbursement than Type 1 PSG studies performed in a sleep center. However, sleep centers can use the 95810 CPT code, which earns full in-lab reimbursement rates, for performing portable video PSG in a hospital setting where a nurse is available for assistance.

While video is helping bring technologists closer to patients in home sleep studies, it is also facilitating in-laboratory studies. Innovations in laboratory-based video PSG systems are enabling technologists to more quickly locate significant events and more effectively communicate them to clinicians and referral sources.

Some PSG systems can graphically show audio and video as waveform channels. For example, if a technologist rapped on the laboratory bedroom door, the line would fluctuate with each knock, rising rapidly at louder noises.

The feature could help technologists reviewing the waveforms post-study to easily find a record, according to Meir Kryger, MD, FRCPC, director of Sleep Medicine Research and Education at Gaylord Sleep Medicine Center in Wallingford, Conn. "Otherwise you would be looking at an eight-hour study in real time," he said "(because) if you fast-forward video, you lose the audio."

When a review of the video unearths something clinically significant, the technologist can export a short video segment overlaid with movement tracking color into the sleep physicians' report to the referring clinician. Those excerpts also can be saved to the waveform file of the patient's study. This enables technologist to discard the larger video files when they no longer are needed.

"One of the rate limiting steps used to be storage," recalled Dr. Kryger, who just published a new Atlas of Clinical Sleep Medicine that includes 40 examples of video recordings from sleep studies on its website. Now, he said, "It's hard to tell where something like video testing is going to go."

One of the places video testing is particularly valuable is in pediatric sleep labs. When children undergo sleep testing, oftentimes a strict waveform recording cannot provide enough information for diagnosis.

For example, patients with upper airway resistance syndrome - a subtle form of OSA characterized by increased upper airway resistance during sleep that leads to increased respiratory effort, sleep fragmentation, and subjective daytime sleepiness - exhibit an apnea hypopnea index within normal pediatric limits. ¹ Video sleep testing offers a noninvasive alternative to continuous nocturnal monitoring of esophageal pressure to measure arousals related to respiratory effort. The camera can capture changes in prone positioning, such as abnormal extension of the neck and protrusion of the jaw, which indicate that the patient is making repeated attempts to re-establish breathing.¹

The technology also exposes other culprits that disturb children's sleep, including co-sleeping with parents who snore or have sleep apnea.

Though many sleep centers initially were slow to embrace video sleep testing, Dr. Kryger said, "Any new facility that starts to do sleep studies in children, or adults for that matter, will have video capability."

1. Banno K, Kryger MH. Use of polysomnography with synchronized digital recording to diagnose pediatric sleep breathing disorders. JAMC 2005;173(1)28-30.

Kristen Ziegler can be reached at kziegler@advanceweb.com.