By Sree Roy
While US sleep physicians remain constrained by fee-for-service reimbursement models that limit home sleep testing to binary sleep apnea diagnosis, their international colleagues are leveraging the same technology to diagnose a comprehensive range of sleep disorders—from narcolepsy to bruxism to periodic limb movement disorder.
This divergence isn’t about technological capabilities. The same type II home sleep systems available in America are being used globally as “home polysomnography (PSG),” emphasizing their similarity to gold standard in-lab PSG rather than “home sleep apnea tests.” The barrier is economic: US reimbursement structures don’t incentivize the comprehensive biosignal collection that makes broader diagnoses possible.
That landscape may change dramatically when new unattended sleep study CPT codes take effect January 1, 2027. As the field prepares for this transition, examining how physicians outside the familiar model are already expanding home sleep testing offers valuable insights into a possible future of the US sleep diagnostics landscape.
The Home Technology Is Already Here
Home PSG technology wasn’t available at the start of the COVID pandemic when it would have been exceptionally helpful, notes Matt Krol, BSc, MSc, MBA, head of the technology department of the sleep laboratory at Herz-Jesu Krankenhaus GmbH in Austria.
But by 2022, new type II home sleep tests were being deployed by the sleep physicians at Herz-Jesu Krankenhaus. There was a learning curve at first. “Our minds changed, like, ‘Oh, it is possible now,” Krol says. “So we started using them on a bigger scale, and now we use them every day.”
Herz-Jesu Krankenhaus sees about 7,500 sleep patients a year since adding type II home testing, up from roughly 4,500 before. It accomplished this without adding to its 15 in-lab PSG systems. Patient wait times are several months shorter, too.
“The technology is here now,” Krol says. “The technology is also very good—it’s equivalent to stationary systems.”
Expanding Home Diagnostic Capabilities
California-based neurologist-sleep physician Anil Rama, MD, has also been using type II home sleep testing for four years. Working outside insurance constraints as the owner of the concierge sleep practice Sleep and Brain, he routinely diagnoses bruxism, arrhythmias, hypoventilation, and periodic limb movement disorder via the Nox A1S. His practice even performs multiple sleep latency tests (MSLT) and maintenance of wakefulness testing in patients’ homes.
Home PSG followed by home MSLT is surprisingly common. “We do at least three every month, sometimes one every weekend,” Rama says.
A sleep tech travels to the patient’s home in the evening to connect the sensors. When the patient is only scheduled for an overnight study, the tech returns the next morning to remove the equipment and scores the data later that same day. For patients who require an MSLT immediately after, upon the morning revisit, the tech stays at the patient’s home for the nap study. “They just stay in another room, but they make sure the patient stays awake,” Rama says. “They score the study from the night before…and then they score the MSLT too.” By the time the patient finishes the MSLT, both the overnight and the daytime nap test are scored and ready for Rama’s interpretation.
In the Netherlands, neurologist-sleep physician Raymond Vogels, MD, PhD, diagnoses REM and nonREM parasomnias, as well as hypersomnias, with a thorough clinical history combined with an Onera home study. “Almost all sleep disorders can be diagnosed using home PSG,” says Vogels, who works at Ruysdael Clinics Amsterdam.
“We now frequently perform home-based recordings that include video, offering diagnostic yield that is nearly equivalent to in-lab PSG,” Vogels continues. However, the lack of in-person sleep tech support during the study, especially for vulnerable patients or children, is a disadvantage, he says.
Still, over the past 15 years, Ruysdael Clinics Amsterdam has reduced its in-lab beds from eight to just one. “A sleep lab setting remains essential in cases where a definitive diagnosis relies on synchronized video and EEG data. This applies to conditions such as narcolepsy types 1 and 2, and complex cases of REM sleep behavior disorder or nocturnal epilepsy,” Vogels says, adding, “It is important to note that, for each study, the raw data remains available for critical review by the referring physician.”
Returning stateside, at least one sleep physician finds that some cases of REM sleep behavior disorder can be diagnosed without an in-lab study. At a SLEEP 2025 symposium sponsored by Onera, a Kaiser physician described using a home sleep test for a patient exhibiting signs of the REM parasomnia. The patient lived on a Hawaiian island that lacked a sleep lab and refused to leave the island, so the physician used EEG, eye signals, and masseter EMG data (together with clinical judgment of herself and a neurologist colleague) to identify REM without atonia and start the patient on clonazepam (which worked).
Meanwhile, in Austria, the Herz-Jesu Krankenhaus research team analyzes data from Onera home sleep tests for cyclic arousal patterns, trying to identify pre-diagnostic markers for Parkinson’s and Alzheimer’s disease through combined EEG, cardiac, pulmonary, and movement data analysis. “We can get so much information out of it for different diseases and even pre-diagnostic states,” Krol says.
Sleep Apnea Beyond AHI
Even when used for straightforward sleep apnea testing, international physicians are already endotyping and phenotyping, rather than relying solely on the apnea-hypopnea index (AHI). They are incorporating metrics such as hypoxic burden, arousal index, and loop gain measurements.
“We want to move away from the AHI and towards endotyping,” Krol explains. “Those parameters are best done with polysomnography systems, and the endotype is very important for treatment outcome and adherence.”
In Germany, Thomas Penzel, PhD, a professor at Charité Universitätsmedizin Berlin, where he is research director of the interdisciplinary sleep center, wants his country to move toward endotyping and phenotyping too. But, like in the United States, the reimbursement structure is holding the technology back.
Payors do not reimburse for type II home sleep testing in Germany. Patients take a type III home test, which, if positive, is followed by an attended CPAP titration study.
Penzel is part of an in-progress prospective pan-European study of type II home sleep tests, in hopes that the data will convince insurers that EEG-inclusive home testing will allow for better therapy selection for sleep apnea patients. “We hope we can change the rules,” Penzel says. “We are interested in phenotyping” for cardiovascular risk in particular.
He says, “We need to explain to them how to put their money to better use…to change their criteria and not just base it on the apnea index.”
How They Use Type III Tests
While these sleep professionals have embraced type II home sleep testing for comprehensive diagnostics, most also use type III home sleep tests—just differently than their US counterparts.
Type III systems serve complementary roles in their practice workflows and are commonly used for initial patient screening and long-term monitoring applications. Also, some physicians do use them for diagnostics in specific patient populations, for instance, people unable to tolerate more than a ring or other one- or two-physical touchpoint systems.
Business Advantages
Beyond clinical capabilities, home testing for sleep disorders for more than breathing disorders offers some operational benefits. For example, due to the constraints on Bay Area real estate, Sleep and Brain did not move into an office that could accommodate a sleep lab bed. But the small office space is working out just fine: Rama discovered patients overwhelmingly preferred taking a test at home anyway.
“Maybe two or three times in four years, I have had a patient say, ‘Oh, you don’t have a lab to come to?’” Rama reports. “Everyone else is like, ‘Oh great, you come to the house. That’s wonderful.’” His practice even maintains a corporate discount code at a nearby hotel for out-of-state patients, conducting 30 to 40 studies annually there.
Rama doesn’t rule out expanding to a larger space with room for a one-bedroom sleep lab in the future. “I’m thinking about doing esophageal pressure manometry again,” he muses, as well as imagining other “super special circumstances” that may necessitate equipment that does not travel well.
Still, Rama’s four-year track record with only type II testing and the occasional add-on equipment (such as an end-tidal carbon dioxide monitor) demonstrates remarkable versatility. “We’ve had a few failures in four years, maybe three or four patients total that didn’t sleep adequately during the night,” he says. In his experience, failure rates are higher for in-lab studies due to the first-night effect.
Preparing for US Landscape Changes
As US reimbursement models evolve, the international experience provides a possible roadmap for expanded home sleep testing implementation. According to international sleep physicians, the technology exists, the diagnostic capabilities are proven, and patient satisfaction is high.
“With the rapidly increasing demand for sleep care,” Vogels says, “it is essential—both in Europe and globally—to explore accessible, efficient, and low-labor-intensity methods of sleep diagnostics, without compromising quality.”
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