Medical background

Medical background

Position therapy has been proven to be an effective treatment method for POSAS

nightbalance_permutstudyApproximately half (56%) of OSAS patients suffer from positional OSAS (POSAS), where the supine AHI is at least twice as high as the non-supine AHI (see Definition of POSAS for references and detailed explanation).

The effectivity of POSAS treatment in remembering the trained sleep position has been tested in various studies since 1980. These treatment methods have been based on making sleeping on your back uncomfortable or impossible through the use of strapping objects to your back, called the Tennis Ball Technique (TBT). This involves, for example, strapping one or more tennis balls, squash balls, special vests, special pajamas etc. to your back, instead of using a vibrating element. The reduction of lying supine is called position therapy.

It has been repeatedly shown that this position therapy can reduce the patient’s AHI to normal levels1,2,3,4,5,6,7. Research by Permut in 2010 further stated that the effectiveness of this therapy is considered equal to that of CPAP.

In 2010 Permut compared position therapy with CPAP and showed that the effectiveness for POSAS patients was equivalent.

Position therapy is included in medical guidelines


Due to its effectiveness, position therapy has been adopted in various medical guidelines as a treatment for POSAS. As such, position therapy has been included in the Dutch ‘Diagnostic and treatment guidelines for obstructive sleep apnea syndrome in adults’8, as well as in international guidelines including the European Guidelines ‘European Respiratory Society Monograph’9 and the American ‘Practice parameters for the medical therapy of obstructive sleep apnea10.


Due to low compliance however, position therapy is not clinically practiced


In clinical practice, position therapy is rarely used to treat POSAS. The key reason for this is the low compliance rates and the few available treatments. It has been shown that the various variations of the tennis ball technique only have a compliance rate of between 20 and 40%4, 12, 13. Even for the most effective treatment, the benefit is only observed when the treatment is actually used. The prescription of position therapy therefore often seems futile for doctors.

The bump strapped to the individual’s back is the cause of low compliance

Sleeping with an object on your back, for the majority of people, disturbs your normal sleep behavior in such a way that you don’t continue using it to sleep. Often the fact that it requires you to fall asleep on your side poses the first problem. Further, the fact that it stops you from being able to turn with ease from one side to the other and the fact that it prevents you from lying on your back at all is too-abrupt an adaptation to your sleep behavior. Furthermore, research has indicated that 20 to 30% of people can sleep on top of the bump strapped to their backs7,11,12.

This is related to the point that vibrations are a better stimulus than pressure. In the long-run vibrations also play a notable role in growing accustomed to the device. The discomfort and the disturbed sleep due to the bump strapped to one’s back are responsible for the low compliance rates and thus the disappointing results in effectiveness of the tennis ball technique. To date patients therefore don’t use these methods on a long-term basis4, 11,12.

A new solution combines effectiveness with good compliance rates

A new technique for position therapy is a small sensor which measures sleep position and through the use of a subtle stimulus corrects it when necessary. This sensor provides noticeable feedback through the use of small vibrations when the patient is lying supine, stimulating the patient to change their sleep position. In this way the sensor reduces the duration in which the patient spends lying supine without reducing the quality of their sleep. Published results demonstrate that this solution does work13, 14. The sensor effectively exerts influence on sleep position and considerably improves AHI without impacting total sleep duration or sleep quality. There have been no side effects detected.

In an attempt to reduce the discomfort of position therapy and improve the compliance rates, the Sint Lucas Andreas Hospital in Amsterdam has conducted research to develop a new treatment method: a small, flat device which uses vibrations to prevent patients from lying supine.

The research team from Amsterdam concludes “that we expect position therapy with such a device to become the sole treatment of position therapy for patients who suffer from light or moderate positional OSAS, whilst patients with a more severe case of OSAS can use such a device alongside other treatments”14.

Simultaneously research was conducted at the TU Delft and the development of an improved device for position therapy commenced. Since 2010 both the research and development teams have been working together towards the research and development of the Sleep Position Trainer.

How NightBalance solves the problems of the bump

NightBalance has developed an active sleep position sensor which is worn around the chest: the Sleep Position Trainer (SPT). This has been introduced in 2012 as a first-class medical aid. The active sleep position sensor is patient-friendly and gradually trains the patient to not sleep supine. The problems of the tennis ball technique (TBT) are circumvented as follows:

1. Ability to sleep on top of a bump with TBT.
With the tennis ball technique individuals still sleep for 20 to 30 minutes per night on their backs on top of the objects This makes the tennis ball technique not only ineffective, but it can also lead to back problems. NightBalance uses active and changing vibrations which, through the use of skin receptors, can be more easily detected than a pressure point especially with larger individuals. Furthermore, the SPT adjusts the strength of its vibrations according to the sleep behavior of the individual. This also guarantees its effectiveness in the long-term.


2. TBT disturbs sleep.
Due to the fact that the tennis ball technique uses a bump strapped to the back, patients can’t easily change position in their sleep. The fact that the individual needs to move over the bump means the individual needs to expend more effort in moving, the duration spent in changing sides is longer and it is more uncomfortable. This disturbs the sleep to the extent that the individuals awake. NightBalance on the other hand is small, flat and ergonomic which facilitates the changing of position as easily as it is without any device. Furthermore, the SPT does not produce a vibration when a patient turns via their back, but only does so when the patient remains supine. This ensures the patient does not notice the SPT when they change position. The SPT is programmed to produce vibrations to a naturally occurring arousal level. By using a natural level of arousal, the natural sleep pattern is not unnecessarily disturbed.

3. With TBT you can only fall asleep on your side.
The perception of comfort is only noticed when an individual is awake. For this reason, the SPT tries to make the individual as comfortable as possible. Some patients desire to fall asleep whilst on their backs. With the tennis ball technique this is not possible. NightBalance incorporates a falling asleep period which allows patients who wish to fall asleep on their backs to do so. Any corrections are then made only when the patient is sleeping.


4. TBT does not allow adjustment.
Due to the fact that a bump is strapped to the back, the individual needs to adjust their sleep behavior immediately. For many people this change is too quick. NightBalance trains people gradually on a step-by-step basis to not sleep supine. The SPT therefore allows the patient to sleep on their backs for some time at the beginning of the training program. This is then gradually reduced.


5. TBT can’t be turned off.
You sleep with it or you don’t. When a patient awakes in the nights and temporarily wishes to lie on their back, this isn’t possible. This causes patients to quickly remove the bump strapped to their back after which they continue to sleep without it. NightBalance can be paused for 20 minutes when the patient desires. When the patient then falls asleep again the sensor re-activates. This prevents the patient from having half a night of apneas (as is the case with the TBT).

Clinical research with the Sleep Position Trainer has elicited positive results

These characteristics create the expectation that it will promote acceptation of the treatment amongst patients, resulting in a high compliance rate in the long-term. Researchers at the Medisch Spectrum Twente in Enschede and the Sint Lucas Andreas Hospital Amsterdam are finishing two clinical studies focusing on its effectiveness and compliance15,16. This research also draws comparisons with the TBT. The results from both researchers show that the Sleep Position Trainer is effective and elicits a high compliance rate. Patients have said that the device is comfortable to use.

Compliance is important, thus monitoring is needed

The importance of compliance is becoming increasingly recognized17,18. This has led to an increased focus on the monitoring of patients, which can increase motivation and facilitate progress checks. The current developments in medical aids for sleep apnea (MRA and CPAP) confirm this trend. The first MRA with compliance monitoring has recently been introduced (Air Aid Sleep,, and a remotely displayed CPAP has also recently been brought to the market to improve compliance monitoring ( van Philips).

NightBalance monitors patients and can be remotely read

Users can read the data from the Sleep Position Trainer and follow their sleep behavior via specially designed software on the computer. This insight into your own therapy’s progress improves the effectiveness of the treatment. The medical specialist can also read the data in this way allowing him/her to better analyze the patient’s progress. Through the patient’s approval in uploading their data, NightBalance can support the patient with the device’s use as well as providing hints and tips to improve sleep. The patients also receive feedback concerning their progress. All of these advantages should improve compliance.


The Sleep Position Trainer brings an innovative medical aid to the market for the treatment of positional OSAS, which can be used for a large percentage of all OSAS patients. Clinical studies show that position therapy can be equally as effective for certain patients as the gold standard, CPAP. Ongoing research with NightBalance’s Sleep Position Trainer indicates high effectiveness and compliance. The device is user-friendly, requires no technical maintenance and has no parts which wear. With the active sleep position sensor NightBalance can offer an effective therapy for positional OSAS patients.

The research team from Amsterdam concludes “that we expect position therapy with such a device to become the sole treatment of position therapy for patients who suffer from light or moderate positional OSAS, whilst patients with a more severe case of OSAS can use such a device alongside other treatments”14.

Simultaneously research was conducted at the TU Delft and the development of an improved device for position therapy commenced. Since 2010 both the research and development teams have been working together towards the research and development of the Sleep Position Trainer.

Recent publication

Recently the article ‘Long-term effectiveness and compliance of positional therapy with the Sleep Position Trainer in the treatment of positional obstructive sleep apnea syndrome’ by J.P. van Maanen, MD and N. de Vries, MD, PhD has been published. The article gives shows the effectiveness, long0term compliance and effects on subjective sleep of the Sleep Position Trainer (SPT) in position-dependent obstructive sleep apnea (POSAS) patients.


The aim of this paper was to investigate the effect of the SPT over a period of six months. In this prospective, multicenter cohort study, adult patients with mild and moderate POSAS were included. Patients used the SPT for six months, and at baseline, after 1, 3, and 6 months questionnaires were filled in. The results show there was a degrease in the percentage time spend supine (21% at basline vs 3% at 6 months. The SPT compliance, defined as more than 4 hours of nightly use, was 64.4%. Regular use, defined as more than 4 hours of use over 5 nights per week , was 71.2%. Subjective compliance and regular use were 59.8% and 74.4%, respectively. Medias ESS (11 to 8), PSQI (8 to 6) and FOSQ (87 to 103) values significantly improved compared to baseline.

In conclusion we can say that positional thrapy using the SPT effectively diminished percetage of supine sleep and subjective sleepiness and improves sleep-related quality of life in patients with mild to moderate POSAS. SPT treatment is long-lasting in its effects. SPT has a high compliance and regular use rate. Subjective and objective compliance data correspond well.

Article: Van Maanen, J.P. & De Vries, N. 2014. Long-term effectiveness and compliance of positional therapy with the Sleep Position Trainer in the treatment of positional obstructive sleep apnea syndrome. Sleep (In press).


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