As expectations for sleep care evolve, new auto-calculated insights—from EEG-based biomarkers to sleep quality indices—can provide clinicians with a more comprehensive view than AHI alone.
By Sree Roy
Many sleep specialists have upgraded their expectations for home sleep diagnostics, seeking additional metrics beyond the apnea-hyponea index (AHI) to better understand a patient’s sleep physiology, symptoms, and/or longitudinal risk.
While most are well-acquainted with the technological variety of home sleep testing devices (HSTs) available—ranging from traditional nasal pressure and thermal airflow-based systems to peripheral arterial tonometry, cardiopulmonary coupling (CPC), and even mandibular movement-based systems—they may lack awareness as to what specific metrics each device can auto-calculate. This is a new question to ask HST marketers at SLEEP 2026 and beyond.
Some HST manufacturers aim for comprehensiveness by reintroducing metrics familiar from in-lab polysomnography (PSG), such as diagnostic-grade electrocardiogram (EKG) and validated central sleep apnea (CSA) differentiation. Others are exploring entirely different facets of sleep, such as autonomic nervous system stability and sleep fragmentation, aligning with a more multidimensional view of sleep health.
“It’s providing, yes, the AHI and maybe the hypoxic burden, but also letting the physician understand what’s actually going on in the body as it relates to sleep-disordered breathing,” says Brennan Torstrick, PhD, co-founder and chief technology officer of Huxley Medical, marketer of the SANSA HST. This shift reflects a broader clinical desire to provide actionable data that informs treatment decisions across a wider spectrum of disorders and comorbidities.
Reintroduction of In-Lab Metrics
One of the primary criticisms of the shift from in-lab PSG to home testing has been the loss of specific physiological signals. For Huxley Medical, the goal was to reinstate the value of the EKG channel in the home setting.
“There’s a massive overlap between arrhythmia patients and sleep apnea patients,” says Brett Klosterhoff, PhD, Huxley Medical’s chief business officer. “Back in the day, if you were to go to a lab, they would hook you up with an EKG, and someone would review your EKG data.”
Huxley’s device provides a diagnostic EKG channel cleared by the FDA that even allows sleep physicians to export formatted strips to facilitate partnerships with electrophysiologists (similar to Holter monitor exports).
Another in-lab expectation transferring to HSTs is the ability to differentiate central from obstructive sleep-breathing events.
After Huxley received separate FDA clearances for its EKG channel and its central sleep apnea detection in 2025, its “high-growth path…significantly accelerated,” according to Klosterhoff.
On detecting centrals, he says, “Clinics that see more complex patients need to have central detection. Also, you see more centrals at altitude, so, for clinics in Colorado and other places that have high altitude, this was a meaningful unlock. But it’s also across the board. People want to have that capability in their HST.”
Data on sleep position is another insight some sleep clinicians demand from a modern-day HST. In a recent Sleep Review Peer Pulse survey, 32% of respondents said all their facility’s HSTs facilitate the diagnosis of positional sleep apnea. Half said only some of their devices could make a positional determination, and 14% said none of their devices did so.1
EEG-Based Biomarkers
Electroencephalography (EEG) is another facet of sleep testing largely lost in the transition to HST. But for the HSTs that utilize any EEG electrodes (typically on the forehead only, where patients can more easily place them themselves), some have developed emerging metrics that differentiate their devices.
Compumedics, for instance, has added a NREM sleep spindle density metric to its Somfit reports. Expressed as spindles per minute, this metric can provide insights into sleep quality, memory consolidation, and cognitive function.
Reduced spindle density has been linked to disorders ranging from depression to Alzheimer’s disease and chronic traumatic encephalopathy. If a patient exhibits unexpectedly low spindle density, it may prompt a referral to a neurologist or an expedited in-lab study.
At Advanced Brain Monitoring, its Sleep Profiler EEG Sleep Monitor is available with auto-detection of sleep biomarkers associated with neurodegeneration.
These tools can enable clinicians to identify abnormal sleep patterns attributed to chronic or neurodegenerative diseases.
Correlating Symptoms with Increased Respiratory Effort
Mandibular movement-based HST marketer Sunrise has introduced a marker called REMOV, an artificial intelligence-powered measure of respiratory effort. A study involving 1,000 adults found that patient-reported symptoms—such as fatigue and sleepiness—are more strongly linked with REMOV than with traditional PSG metrics like the AHI.2
This is particularly relevant for women and patients with “mild” obstructive sleep apnea. “REMOV offers an accurate view of respiratory effort, helping clinicians understand what’s driving symptoms and identify patients who may be overlooked by AHI-centric assessment,” says Laurent Martinot, co-founder and CEO of Sunrise Group, in a release.
Jean Benoit Martinot, MD, head of the Sleep Service and Laboratory at the Université Catholique de Louvain, notes that objective assessment of residual effort is critical. “The persistence of snoring, meaning the persistence of a high level of REMOV…is tightly associated with the risk of systemic hypertension,” he says, emphasizing that sleep partner reports of snoring are often unreliable.
Growing Interest in Hypoxic Burden
Hypoxic burden—a measure of the frequency, depth, and duration of oxygen desaturations—is rapidly becoming a standard expectation for HST reports. While the AHI measures the prevalence of events, hypoxic burden is viewed as a more accurate reflection of disease severity and cardiovascular risk.
Several companies have integrated or are planning to integrate this metric. Wesper, which utilizes a patch-based system, provides hypoxic burden as part of its standard reporting. Other devices that can auto-calculate hypoxic burden include the PranaQ TipTraQ and Nox Medical’s Nox Connect, which debuted at the SLEEP 2025 meeting. SANSA’s hypoxic burden will be released at SLEEP 2026 by Huxley Medical and presented in the meeting’s scientific program.
Multidimensional Sleep Health
The trend toward more diverse HST metrics aligns with the American Heart Association’s (AHA) recent scientific statement acknowledging that sleep health is about more than just duration or the presence of apnea.3
The AHA highlights several components—sleep continuity, timing, satisfaction, regularity, and daytime functioning—as critical contributors to cardiometabolic risk factors, including high blood pressure, cholesterol, and glucose intolerance. As HSTs begin to provide metrics that track these dimensions, they become more useful for primary care, cardiovascular care, and pediatric care.
For instance, SleepImage uses CPC technology to provide metrics that reflect the balance of the autonomic nervous system. Its metric, the Sleep Quality Index (SQI), offers a scale from 0 to 100 to reflect restorative sleep.
“SQI is a summary metric of all the sleep event outcome parameters,” says Bogi Palsson, CEO of SleepImage. “It reflects autonomic activity that reflects health outcomes. It’s been correlated with several cardiovascular and metabolic outcomes, and brain and mental health. It seems to separate health from disease and disease progression well.”
SleepImage also provides metrics for sleep fragmentation and periodicity. Fragmentation, measured via autonomic arousals, can be a practical tool for optimizing titration. “If you overtitrate an oral appliance or CPAP…it may cause an arousal,” Palsson says. Having an independent measure to find the balance between treating apnea and maintaining sleep continuity is part of the move toward precision medicine.
Periodicity serves as a unique biomarker, identifying periodic breathing and heart rate patterns that may indicate sustained periods of CSA, high loop gain, or periodic leg movements. According to Palsson, this measurement has proven to be a better predictor of outcomes in patients with central sleep apnea than many traditional methods.
Should the ‘Core’ Metrics Change?
As the marketplace differentiates, the question of whether all HSTs should provide the same set of “core” metrics, and what they should be, intrigues.
For many practices, the choice of an HST may now depend on specific patient demographics, geography, or areas of clinical interest. A clinic in a high-altitude region may prioritize a device with validated CSA differentiation, while practices wanting to track sleep health over a patient’s lifetime may opt for one with longitudinal-friendly sleep quality metrics.
Peer-reviewed validations of new metrics should be encouraged, as should innovation.
Ultimately, the expansion of HST metrics allows sleep professionals to move beyond a binary “yes/no” diagnosis for sleep apnea. By supporting technologies that provide the metrics they want to see, clinicians can encourage further innovation.
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References
1. Roy S. Two years in, Medicare coverage for positional OSA therapy still flies under the radar. 2025 Dec 15. Sleep Review. Available at https://sleepreviewmag.com/sleep-treatments/therapy-devices/positional-therapies-supine/medicare-coverage-positional-osa-therapy-under-the-radar/
2. Martinot JB, Le-Dong NN, Clause D, et al. Respiratory effort burden measured by mandibular jaw movements as a digital marker with clinical insights in obstructive sleep apnea. Commun Med (Lond). 2026 Jan 12;6(1):112.
3. St-Onge MP, Aggarwal B, Fernandez-Mendoza J,et al; American Heart Association Council on Lifestyle and Cardiometabolic Health; Council on Cardiovascular and Stroke Nursing; Council on Clinical Cardiology; and Council on Quality of Care and Outcomes Research. Multidimensional sleep health: Definitions and implications for cardiometabolic Health: A scientific statement from the American Heart Association. Circ Cardiovasc Qual Outcomes. 2025 May;18(5):e000139.
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