Home sleep testing becomes more accepted as technology advances and the need for sleep testing becomes more prevalent

imageIt has been a decade since sleep studies moved out of the laboratory setting and into the home environment, but arguments still rage in the clinical community over whether the home studies should be used at all. Traditional proponents of laboratories see a number of negatives regarding home testing methods. However, slowly, with advanced technology, cost pressures, and patient interest, home sleep studies are taking hold. So on what side of diagnostic testing in the home should the sleep community be? Is there a place for home sleep studies at all? And how can the two sides come to an agreement as to the home sleep study’s place in the diagnosis of sleep disorders?

Makeup of Sleep Studies
“There are two schools of thought in sleep diagnostic testing,” says Patrick J. Dunne, MEd, RRT, FAARC, a consultant in the home health care arena. “Each has advocates and tends to be pretty passionate.”

Sleep testing is typically used as a screening tool for obstructive sleep apnea (OSA) by measuring oximetry, nasal/oral airflow, and respiratory effort. The traditional method of sleep study is done within a sleep laboratory in a freestanding building, or in a hospital. In the 1970s and 1980s, sleep studies began in these controlled environments, which were long considered the only places that could perform polysomnographic testing. The tests use an electroencephalography (EEG) parameter to document evidence of sleep staging—the most important component of a sleep study.

“We are trying to find out when the patient goes into rapid eye movement (REM) sleep, which is when obstruction of the airway occurs,” Dunne says. “That is also the point when the body repairs itself and it is important for it to rest and rejuvenate. The most important part during the test isn’t the change in heart rate, brain waves, or oxygen saturation, but putting all of that together and coordinating it with the stages of sleep.”

Typically, either a neurologist or a pulmonologist is the medical director of such a laboratory, and polysomnographic technologists attend training programs where they are taught how to attach electrodes, set up monitors, teach patients to rest, and then download the equipment and get reams of paper with the recorded parameters for 8 hours. They then read and score all the information and present the data to a physician, who makes a diagnosis based on the results and prescribes nasal continuous positive airway pressure (CPAP). The amount of CPAP required is then determined in a second night study that repeats the first night’s study only the patient is now wearing the CPAP device. A technician outside the room monitors the patient’s sleep, titrating CPAP and adjusting it repeatedly over the course of several hours to determine the amount of CPAP necessary to keep the patient from obstructing.

At present, there are approximately 3,000 sleep centers, laboratories, and sleep testing facilities in the United States, and sleep center-based polysomnography is considered the gold standard for sleep study data acquisition, scoring, and interpretation.1 However, home studies are cropping up in an attempt to remedy the problems associated with sleep laboratories, including their sterility. The pro-home study argument contends that the laboratories introduce an artifact not conducive to home sleep. Sleep laboratories are also very costly, so their limited number leads to a backlog of patients. Regardless of those issues, sleep laboratory proponents argue that results in a controlled environment are reliable and reproducible—something that is not the case in home studies.

“When the concept of a home-based unattended sleep study first started, the big argument was over the fact that, though we can get oxygen and pulse and heart rates, we can’t stage sleep. So what good is it?” Dunne points out. “At the very best it can be a screening without the sophisticated equipment of a sleep laboratory. However, with telemetry, the Internet, and digital technology, all that is now possible in the home.”

The Comfort of Home
Patient comfort frequently comes up as a primary benefit of home-based diagnostic testing. The artificial laboratory atmosphere is not conducive to sleep, and the argument is made that patients will be more likely to have realistic sleep patterns in their own bed. A comfortable environment avoids issues of disruption, onset of insomnia, and changes in typical sleep patterns brought on by sleeping in a laboratory setting.

“If you asked 100 patients who had sleep testing performed, and 50 were tested in an institution and 50 were tested at home, the satisfaction survey would show that those tested in the home would be a lot more impressed,” Dunne says. “People prefer receiving any type of care in the home. For someone who has a sleep disorder, trying to diagnose and quantify that in their home means minimal anxiety for the person.”

Advances in Technology
Supporters of home testing also cite the minimal impact on the home environment, largely due to advanced technology. Today, a patient can be visited at home by a registered polysomnographic technologist who can bring modular equipment that is the size of a notebook.

“No one knows how many are doing it as in-home testing,” Dunne says. “The Internet really changed the dynamics of how data are transmitted. In the past, technicians had to lug the data in suitcases, then take it to a laboratory to download. New software has made all of the data practically read before it’s downloaded. It can be emailed to the physician who will then send back the results.”

This advanced technology, Dunne argues, can even nullify a major point of contention among supporters and opponents of home testing—the fact that it is done unattended.

“What if the leads fall off, or the patient rolls over and pinches the wire? With today’s technology, we have ways around this problem,” he says. “We can take the telephone line, plug it in to the monitors, and set up a station where the equipment calls up the monitor to see if all the leads are working.

“We can even have a technician call throughout the night to check the machines,” he continues. “If a lead becomes disconnected, the technician can go through another line, wake up the patient, and tell them to reattach the electrodes. Technology has really pushed the argument much more toward home testing.”

The newest technology on the market that could potentially represent a watershed for home testing is a smart CPAP that auto-adjusts based on the level of obstruction.

“At the end of the first night, the technician will download the data, have a physician read it, and perform the same test the next night using an auto-CPAP, which has a recording feature,” Dunne says. “This uses the same electrodes and telephone hookup. Then, in REM sleep, during obstruction, the machine will respond and apply pressure as needed to keep the airway open.

“At the end of the test, the computer will download the memory from the CPAP machine and find out when the most consistent level occurred during sleep and correlate it with the sleep study,” he says. “The physician can then arrive at a prescription of appropriate CPAP. It’s all automated.”

Backlog of patients
Even with 3,000 sleep centers in the United States, there still is a backlog of patients waiting to get tested for sleep disorders. Offering home testing would automatically reduce that backlog and speed up the process across the board.

“There is typically a backlog of about 6 weeks, a few days to get the report read, and another 6 weeks to reschedule,” Dunne says. “Performing studies in the home allows you to get the test done in a few days.

“In addition, the hospital laboratory has a limited number of beds, so there are only a certain number of tests being performed in hospitals. A home company can do 15 to 16 studies a night—it just needs the equipment,” Dunne says.

Todd Eiken, RPSGT, director of the Metropolitan Sleep Disorders Center, St Paul, Minn, and past president of the Association of Polysomnographic Technologists (APT), is also an advocate of home sleep studies. Prior to joining the Metropolitan Sleep Disorders Center, Eiken worked for a home medical equipment company in Alabama, where he established a home sleep study program.

“There are people who would otherwise never come to a sleep disorders center if it weren’t for portable monitoring, so I think it should be looked at and used,” Eiken says.

Within 3 years of focusing on home sleep studies, Eiken saw a 70% success rate based on patients’ subjective reports on follow-up visits. Bed partners likewise described much quieter sleep, no snoring, and an apparent elimination of symptoms.

“In that regard, the outcomes were positive, but because no technologists were observing them, and the actual titrations were auto-adjust algorithm, we don’t have any objective data indicating that the patients had been cured or that the treatments being utilized are the most appropriate for the patients,” Eiken says. “The upside is that those patients living in rural areas would not likely have traveled to a big city sleep center for treatment.”

The Downside of Home Sleep Testing
Of course, there are some problems with home sleep studies that even its advocates recognize. The most crucial is the possibility of incorrect results, which not only postpones accurate diagnosis of OSA, but also negates any economic advantages to home sleep studies.

“Often there is no EEG being recorded and you don’t know if the patient is asleep or not,” Eiken says. “Consequently, there is a high incidence of false positives. You cannot effectively titrate nasal CPAP because these studies are typically unattended and that leads to a large amount of artifact contaminating the reports.”

Also missing is objective evidence that the new auto-CPAP technology actually works. Eiken contends that the movement toward in-home monitoring methods is really being pushed by the manufacturing industry.

“In a recent study of four different machines, we used an identical titration pattern, and all of them responded differently,” Eiken says. “We use auto-adjust CPAP devices in a full-service sleep laboratory for follow-up purposes but not for diagnosis. All anyone really has to go by are the subjective reports of how patients feel. We really don’t know what we did, how it was done, or whether treatment is optimal for that particular patient.”

Picking up signs of other sleep problems is also an issue with unattended sleep studies. “How do we get around not having an attendant observe the positioning of the electrodes?” Dunne asks. “What about recorder malfunctions? There are issues with having an attendant in your home. How many people can you hire to babysit someone in the home?”

The Economic Factor
In an effort to keep costs down, Pamela Minkley, CPFT, RRT, RPSGT, notes the possible sacrifice of technical competence. Minkley is a member and past president of the APT. In a recent article on the topic of home sleep studies for RT Magazine, she writes, “The quicker and easier it is to do sleep studies in the home, the simpler it appears and the more likely that inexpensive equipment will be available to use in the home, and that physicians untrained in the sleep medicine will be ordering and interpreting the study.”2

“You do need someone experienced in full-service testing to review and analyze data acquired by the ambulatory method,” Eiken says. “Unfortunately, a lot of portable units contain auto-analysis programs, which at best are 50% accurate in all brands of equipment. They are not reliable, although they are marketed as being accurate.

“There are people out there who provide home testing services and have no idea about recognition of artifact during analysis and rely exclusively on auto-analysis devices,” he adds. “They are very inaccurate, which is another reason why home sleep should be conducted only by sleep professionals.”

Finally, Eiken notes that current reimbursement amounts for unattended polysomnographic monitoring are so low that it is difficult to break-even to perform these studies. “There is absolutely no incentive to even get into it,” he says.

The Future of Home Sleep Studies
Regardless of those issues, proponents of home sleep studies say they should not be thrown out altogether, Eiken included.

“I think one of the primary advantages of home sleep studies is that they can take the place of night-one components of the conventional 2-night protocols used in the majority of the country,” Eiken says. One exception is the Metropolitan Sleep Disorders Center, which, like many sleep laboratories in certain areas of the country, participates in a split-night study dictated by insurance companies. That precludes home-based testing.

“We do the baseline portion and treatment initiation portion all in 1 night,” he says, “so there is no benefit or cost savings to performing in-home studies for 2 nights.”

In cases of sleep laboratories doing 2-night studies, an in-home test on the simpler first night would alleviate some of the patient backlog and eliminate the baseline from the laboratory equation, which would then do an all-CPAP titration study.

“You can do the first night component without CPAP in the home,” Eiken says. “Then you will be doing the full level-one polysomnography with nasal CPAP titration in the laboratory. That may actually represent an increase in revenue for a sleep laboratory to utilize in-home studies.

“I would think if the sleep community as a whole could eliminate the more expensive night-one polysomnography component, insurance companies would be in favor of that,” he continues. “Full-service laboratories should embrace home sleep methodology. They should be the innovators and determine how it should be used. Aside from that, there are benefits to both. It should be a joint effort, especially because of excessive artifacts as a downside.”

According to Dunne, there currently is no rhyme or reason as to whether sleep laboratories are currently utilizing home sleep studies.

“It just depends on the business sense of people setting up the service, how well they get the idea before significant opinion makers and physicians, and how many underserved patients are in the community,” he says.

“The sleep industry ignores home studies to a certain degree. There are those out there who are trying to embrace it, but for the most part it is ignored,” Eiken says. “The reasons include a feeling of being threatened that the laboratory’s business is going to be adversely affected by portable service providers. My take is that there are so many patients in need of testing that, even though [home testing] may be competition, it’s hard to believe there will ever be a lack of patients, particularly for OSA.”

Advocates of home testing are likely not to be heartened by what may be a move by the clinical community in the direction of recognizing the advantages of such diagnostics. A recent workshop on the use of portable monitors for the diagnosis of sleep apnea was organized by David Hudgel, MD, professor of medicine at Case Western Reserve University, Cleveland, and was attended by representatives from the American Thoracic Society, the American College of Chest Physicians, and the American Academy of Sleep Medicine. A paper on the outcome of the workshop is expected to be produced in the next few months. Advocates are also pushing the American Academy of Sleep Medicine (AASM) to accept home-based testing to some degree.

“The AASM currently has standards for hospital laboratories as far as monitoring, training, and interpretation for certified laboratories, and they don’t take too kindly to home-based issues,” Dunne says. “But the marketplace is pushing them into providing credibility to home centers. On average, the home test is every bit as good as the hospital test in today’s environment, and the traditionalists and the avant-garde are on common ground in wanting testing done correctly, wherever it’s done.”

Liz Finch is a contributing writer for Sleep Review Magazine.

1. Minkley P. Sleep testing: center- and home-based. Respiratory Care. 1998;43:296.

2. Dunne PJ, Minkley P. Pros and cons of home sleep studies/sleep studies should not be performed in the home. RT Magazine. 2000;13(3):100.