Paid for by SleepImage
SleepImage will launch a personalized fingertip home sleep testing device at SLEEP 2023. The new device, which is designed for single-patient use, needs no consumables and can record and transmit data from hundreds of patient nights to their clinicians, facilitating longitudinal monitoring of sleep.
SleepImage also continues to sell the SleepImage Ring, which is designed for multi-patient use. Both devices are compatible with SleepImage’s Software, which is cleared by the US Food and Drug Administration (FDA) as Software as a Medical Device (SaMD) to aid in the evaluation of sleep disorders, diagnose obstructive and central sleep apnea, and to manage sleep disorder treatment. It is cleared for use for children 2 years of age and older, adolescents, and adults.
The SleepImage technology is based on the two fundamental signals that underlie human health: heart rate variability (HRV) controlled by the autonomic nervous system (ANS) and breathing.
“When you couple these two core signals, HRV and breathing, that define all of us—the true differentiators between health and disease, life and death—they produce a stable signal that represents health and/or sickness during sleep,” says Bogi Palsson, CEO of SleepImage. “That’s one of the reasons the FDA has given SleepImage the clearance for a metric called the Sleep Quality Index (SQI). The SQI has demonstrated in many peer-reviewed publications that it reflects health during sleep, both in children and adults, including blood pressure control, cardiometabolic markers, and even some brain health markers.
Also referred to as cardiopulmonary coupling (CPC), a wealth of health data is embedded in the combination of HRV and breathing. “Largely, this information wasn’t previously understood and therefore couldn’t be utilized, but it’s always been there,” Palsson says. “There’s no artificial intelligence involved in the SleepImage technology. It is just pure old-fashioned physiology.”
In fact, viewing sleep through the autonomic nervous system (where respiration and heartbeats are controlled) gets as close to measuring the activity of the midbrain—where sleep is controlled—as noninvasive technology allows. “The method that SleepImage utilizes looks at health through the ANS, which is very, very, stable and the stability means that it’s very accurate,” Palsson says.
The home sleep testing devices marketed by SleepImage—the SleepImage Ring and the new personalized fingertip device—are photoplethysmography sensors. Many other photoplethysmography (PPG) sensors collect the signals to evaluate HRV and breathing so are also compatible with SleepImage’s Software as a Medical Device. SleepImage can turn data from various devices into meaningful and actionable health information.
The features of SleepImage’s two home sleep testing devices include:
- New personalized device: wearable device placed on the fingertip, that is reusable for a single patient for longitudinal monitoring, no consumables, no wires, rechargeable battery, sized for adults, Bluetooth communication with the SleepImage mobile patient app (used for temporary storage only; wiped after upload), web-based clinician portal, raw and auto-scored sleep study data is available.
- SleepImage Ring: wearable device placed around the base of a finger, reusable for multiple patients, no consumables, no wires, rechargeable battery, sized for adults and children, Bluetooth communication with the SleepImage mobile patient app (used for temporary storage only; wiped after upload), web-based clinician portal, raw and auto-scored sleep study data available.
Palsson shared more details of the fingertip home sleep test with Sleep Review via a video interview. This transcript has been lightly edited for clarity and editorial style.
What was the inspiration for the new SleepImage device?
The inspiration was a market requirement. The market is split into two functional requirements: one is a functional requirement based on ease of use, which is often dubbed as disposable devices, which is a market in which SleepImage has not been playing in; and the other one, is the market of reusable devices, which is the market that SleepImage has been playing in.
There are pros and cons to both. The pros of the reusable devices are material utilization and earth-friendliness. The convenience that we see with disposable devices is that no logistics are required for sending devices back and forth or cleaning them between different patients and so on.
What inspired us to look for this uniqueness in the SleepImage ecosystem? We can marry the best of both worlds: We could add to our arsenal a personalized device, meaning that it goes to one patient and stays with that patient. But the uniqueness apart from disposable devices is that the device is not disposable. It is our belief that this device can be used to improve the precision of care for patients who have been diagnosed with sleep apnea, whether that’s utilizing the remote patient monitoring codes or any other payment mechanisms for continued monitoring to measure the efficacy of the treatment.
Currently, there are only compliance metrics available from CPAPs with no output metrics whatsoever from oral appliances, so there truly is very limited efficacy tracking in sleep medicine today to measure outcomes for patient benefit. SleepImage can bring a valuable component to improve sleep care from the precision of diagnosis to the precision of the treatment itself by tracking treatment with a personalized device, similar to how hypertension is tracked over time to optimize outcomes and quality of life for the patient.
SleepImage has the ability to meet the disposable devices on the price level, but what sets us apart from them is that this device is not disposable, so it can be utilized for improved patient care, similar to a blood pressure monitor for hypertensive patients.
How is the form factor different from the SleepImage ring?
In one sense, the form factor is different: one is a ring on your finger (the form factor that SleepImage has been using), with this new form factor being sensor that is worn on the fingertip.
In some ways both devices share the same form factor as both are worn on the finger; both collect the same data; record the same physiology; and that physiology is sent through the SleepImage mobile app to the SleepImage cloud, where it is analyzed to produce the six-channel outputs reported in the SleepImage System.
Were there challenges in creating the new form factor?
There weren’t really any challenges, and I say that because of the FDA clearance SleepImage has—which is for SaMD, a relatively novel concept that has been around for less than 10 years.
What it means is the input to the medical device is defined based on data acquisition characteristics. It means that SleepImage can take data from the SleepImage Ring, as well as take data from this new fingertip form factor; the SleepImage System could even take data from any polysomnography (PSG) system or any hospital monitor because all these devices have the sensors that collect the signals that the SleepImage System needs for the data analysis to produce sleep data output.
So there is a wide availability of devices that SleepImage could utilize to collect data for the intended use of the SleepImage System SaMD. That’s why there were really no challenges in this for SleepImage.
What signals specifically do you need?
That’s another unique feature of SleepImage compared to many of the newer technologies: we use a nonproprietary signal input from sensors that are commonly used.
All of the data and the data analysis has been explained and published in peer-reviewed clinical literature. So there is no ‘black box’ magic. SleepImage uses true physiological signals collected with a photoplethysmograph sensor, which is part of any and every PSG system, it’s on every hospital monitor, and these are the same sensors that are on many common consumer devices. The photoplethysmographic (PPG) sensor has become a commonly used and understood sensor technology that is widely used on both medical devices and consumer devices.
The signals collected by the PPG sensors create the input fed into the SleepImage System. Embedded in the plethysmograph waveform is information on pulse (heart) rate variability (PRV/HRV) and respiration, as well as additional information that could be derived, such as for arrhythmia detection (which we don’t do) or for respiratory rate (that is currently not displayed on the SleepImage report).
The SleepImage System also displays the six raw data channels that can be used for further analysis and manual scoring of respiratory events for sleep apnea diagnosis because the data that is collected is continuously and evenly sampled.
What is proprietary in SleepImage is the coupling technique of HRV and the breathing component, hence the term cardiopulmonary coupling (CPC), which is the name behind the SleepImage technology. At its core, it is a Type 3 sleep testing device as defined by the American Academy of Sleep Medicine as “limited cardiopulmonary testing.” So the definition of a Type 3 test literally utilizes the name of the SleepImage technique.
It sounds like the technological challenge is pushed onto the algorithms and the analysis, and it’s not really in the device. Is that accurate?
Absolutely; there is nothing proprietary in the hardware device. That’s why we can utilize a variety of different signal recording devices to record these physiological signals that are then utilized for the CPC-analysis in the cloud-based software. The data analysis and the output is created by the SaMD. That does not indicate that the software is creating any channels, it is just utilizing the channels that are embedded in the signal.
What populations has the software been tested on? For example, many times pregnant women aren’t included in datasets. I was just curious about this.
There have been tests on pregnant women. There have been tests on children. There have been tests on patients with all kinds of chronic conditions. There are over 100 peer-reviewed publications published on the SleepImage technology. It’s been compared to tens of thousands of study results in prospective clinical trials from PSG.
One of the benefits of having SaMD is it allows SleepImage to take data from prospective clinical studies that have been conducted and then taking that signal from those studies, analyzing it through the lens of the CPC- technique, and comparing the output of that to the output of the PSG from the original study. Which in a sense makes this analysis even more rigid than if we had any ability to recruit and define the patient population and define what is success and what is not, and which patients should be included or excluded.
When SleepImage performs a secondary analysis of data from other people’s prospective studies, we are at the mercy of how the original study was designed.
What are the outputs? Are there waveforms or just algorithm-derived values?
The output values that SleepImage provides are derived by the CPC-algorithms. In addition, raw data is provided that can be looked at second by second throughout the entire sleep period.
SleepImage displays 6 raw data channels, the raw plethysmographic signal itself; the heart rate signal; the heart rate variability; a respiratory signal, actigraphy, and SpO2.
The SleepImage system displays both autoscored respiratory events on the respiratory signal and on the SpO2 signal, which can be overwritten by a technician or a physician to change events, add events, and delete events. The SleepImage System respiratory and SpO2 channels can be manually scored just like a conventional home sleep apnea test for diagnosing obstructive and central sleep apnea. In addition, technicians/physicians can compare their own conclusions to what the auto-detection determined and write clinical notes and diagnostic conclusions.
What is your advice for a sleep specialist who does not know whether to use the original SleepImage Ring or the new fingertip device in their practice?
It’s primarily a function of their own workflows.
You can get to a lower cost per test and per patient by using the reusable devices because the cost of the device itself becomes so insignificant over time. To get to that lower cost, the user has to be willing to do the logistics. The logistics include either handing the Ring to patients in the practice or shipping it, as well as cleaning, recharging, repackaging, and preparing it for the next patient.
Or if you want convenience, use the single-patient fingertip device. The initial cost is a little bit higher for that patient. But since the patient now has that device in hand, and let’s say the patient is diagnosed with a sleep disorder, they go on to treatment. Now they have a device—akin to a blood pressure monitor for cardiovascular conditions—to manage their sleep apnea treatment, which likely may lead to improved outcomes from the precision of care that becomes possible with objective data collected over time that can be used to titrate the treatment intervention.
So for clinicians who are, for instance, interested in the value of remote patient monitoring to improve the precision of care for these patients, now they have a very, very, very low-cost option to manage these patients over time. This option will likely enhance the value for the insurance payer, the patient, and the clinician practicing remote patient monitoring by utilizing these personalized devices that can be used repeatedly without requiring any single-use consumables.
To summarize, those with good logistics in their practices and are only focused on diagnosis, the lower cost will be to use the Rings, which can be used with multiple patients. For those who want to take a look at longitudinal care for their patients and/or reduce the logistical part within the practices, I would recommend the fingertip personalized device.
What about the cost and reimbursement of the SleepImage devices?
The reimbursement is based on the use.
CPT 95800 is defined as an unattended sleep study with simultaneous recording of heart rate, oxygen saturation, respiratory analysis, and sleep time. SleepImage meets the definition of CPT 95800 with a true measure of sleep time (which measures sleep through the autonomic nervous system, not with an estimation of sleep utilizing actigraphy).
The remote patient monitoring (RPM) codes are defined as having to utilize a medical device (as defined by the FDA, which is our Software as a Medical Device), to measure a minimum of 16 measurements over any 30-day period with the ability for the patient to measure every day or every night. We’ve got personalized plans available for that, which will make it possible to adhere to the requirements with minimum effort or inconvenience for the patient at a cost that will make it financially viable to improve outcomes and very likely lower healthcare costs for these patients.
There is no concern about single-use consumables or new devices that have to be bought. You could have a device like this fingertip device given to a patient by a clinician originally and utilized for this purpose, together with the Software as a Medical Device for the analysis and creation of the output, and they could measure themselves every night if they wanted to for a full year if they wanted to.
That is how SleepImage can defy the concept of disposable devices and sleep apnea diagnosis. It is time to start treating sleep apnea as the chronic condition that it is.
See the fingertip device in person: SLEEP 2023 Booth #532