Conference “Biomedical Engineering“
Electronic means used in sleep medicine. A review
Raul Kala
Member of Estonian Sleep Medicine Association, Estonia
E-mail: raulkala@gmail.com
Introduction. Today's sleep medicine technology relies on electronics
and therefore it is appropriate to talk about electronical sleep medicine devices.
Since Hans Berger's brain electroencephalographic recordings in 1924 [1],
electronic sleep medicine technologies have evolved fast, and have turned into
a complex field of science.
Diagnosis and therapy of more than 80 different sleep disorders need
specific devices [2]. Considering the vast amount of different electronic sleep
medicine devices nowadays, there is an obvious need for an overview.
Classification of the sleep devices. Classification of the sleep devices is
vague because many classes of the devices have overlappings with the others.
Contemporary electronic devices have become very complex, and thus cannot
be distinguished by working principle. However, some kind of classification of
the electronic sleep medicine technology devices is possible to accomplish.
In Fig. 1 is presented a patient based
Sleep
disorder
approach, which shows
patient
the use of the sleep
medicine devices according to the needs.
Visite to the doctor
In this short
overview the sleep
Choosing the appropriate method(s) of diagnosing
medicine devices are
Image
Online sleep
Wearable
Beds and
PSG
DASS
devices
diaries
devices
pillows
devided into 6 classes
as seen below.
Determining the cause of the disease
- diagnostic devices,
- therapeutic devices,
Choosing the appropriate method(s) of theraphy
- wearable devices,
- image devices,
CPAP
BiLevel
LAUP
UAS
- beds and pillows
- online sleep diaries.
Curing process
In the following
sections
these
6
NO
Is the patient satisfied
classes of electronic
with the results
?
sleep medicine deYES
vices are described in
Patient cured
more details
Fig. 1. A patient based approach of the use
of the electronic sleep medicine devices
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Conference “Biomedical Engineering“
Electronic diagnostic devices. In sleep medicine the main electronic diagnostic devices are polysomnographs and fatigue evaluation devices DASS.
Polysomnograph (PSG). The main electronic diagnostic device in sleep
medicine is polysomnograph, a device measuring the variation of many parameters during sleep. Minimum requirement for polysomnographic recording is
simultaneous recording of EEG, EMG and EOG. During polysomnographic
recording breathing, ECG, snoring sound, temperature and hemoglobin oxygen
supply signals can be additionally recorded.
DASS (Depression Anexity and Stress Scale) is a car driving simulation
system, which is used for assessing the patient's fatigue. During the DASS
study the patient is asked to drive a car in a simulator, following the road
appearing on the simulator’s screen. The patient's ability to endure monotonous
activities, response of speed, and sleep-specific brain activity signals are
measured by the signals from the electrodes placed on the patient’s head [3].
Electronic therapeutic devices. At present there are four electronic sleep
medicine devices, which can be classified as therapeutic devices – the continuous positive airway pressure CPAP device, BiLevel, LAUP and UAS devices.
CPAP. Continuous Positive Airway Pressure (CPAP) device was introduced by Gregory et al. [4] in 1971. The CPAP is a nonivasive device that provides
ventilation using constant positive airway pressure by blowing the air through the
mask into the patient’s airways, thus avoiding the appearance of the symptoms of
apnoe. Since patients may experience a dry mouth, there exist also devices, which
moisturizes the air blown into the patient’s airways with a heated humidifier.
BiLevel. In addition to the creating of continuous air pressure, as it is
produced by the CPAP devices, the BiLevel noninvasive air pressure devices
create two different levels of positive air pressure. The level of pressure of air
increases when the patient breathes in, and decreases when the patient breathes
out [5]. This property of the BiLevel devices allows the pressure creating
devices to be used also by these patients who cannot use the CPAP.
LAUP (Laser-Assisted Uvulopalato-plasty). In 1990 a new anti-snoring
procedure called LAUP was introduced in France. LAUP is a therapeutic
procedure during which after the implementation of sedation, the CO2 laser is
used to reduce the size of the palate and uvula. Regardless of surgical operation
of laryngeal tissue, the LAUP procedure can be accomplished repeatedly [6].
UAS. (Upper Airway Stimulation) is a device of the company Inspire,
which uses the electrical stimulation of the hypoglossal nerve to prevent
obstructive apnoe [7]. The device consists of implantable pressure sensor, pulse
generator and stimulation electrode. The pulse generator is needed for
processing information from the pressure sensor and to find the most beneficial
time to deliver the electrostimulation [7].
Wearable electronic devices. In sleep medicine wearable medical electronic devices allow to notice the progression of the disease at an early stage
and to monitor subsequent course of treatment changes. Wearable electronic
devices find primarily use as ribbon-mounted headsets, actigraphs and vests.
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Conference “Biomedical Engineering“
A headset is a data acquisition device, worn ribbon-mounted on patient's
head. The main advantage of the use of the headset is its ability to measure
the EEG signals [8]. If needed, additional electrodes can be added.
Vests allow to measure breathing activity, ECG, temperature of the body,
and much more [9]. Electronic vests, used as body area data aquisition systems,
allow long term measurement of patient's activity inside and outside the bed.
Actigraphs are small sized wrist worn devices for recording movement
activity. They were probably taken into use as early as in 1972 [10]. There are
two types of actigraphic devices: accelerometric and multi-sensor devices.
Image acquisition devices. For the acquisition of patient's sleep time
image and health status mainly thermographic IR and video recordings are used
in sleep medicine [11].
Specially equipped beds and pillows. This is a new branch of electronic
sleep medicine devices, which has come out with beds and pillows, supplied
with electronic devices.
Electronic pillows. Today the pillows enriched with electronic devices are
able to detect snoring and sing lullabies [12]. Company Philips has created a
system consisting of a pillow and a flax that monitors patient's heart status [12].
Electronic beds. The 1987 report of Honeywell Corporation stated that
people are eating, working and watching TV in bed. Accordingly, the TV,
positioning systems and much more were added to the bed. After 1988 Honeywell and Microsoft Corporation conducted research on beds, and it became evident that electronic beds are an integral part of our lives [13]. Possibly the most
innovative electronic bed is a capsule created by Matsushita Electric Works.
Inside the capsule is created the environment for sleepiness and alertness [14].
Online sleep diaries. The use of online sleep diaries helps to create a
more efficiently working internet environment between the doctor and the
patient. Traditionally used sleep diaries are not very efficient because data
entries on paper are not exact. Online sleep diaries help to stamp the time of the
sleep events and to show many interesting medical characteristics. Therefore it
is important to understand that online sleep diaries are an integral part of
modern electronic means used in sleep medicine [15].
Conclusion. Electronic sleep medicine devices are highly complex and in
most cases the use of these devices need highly skilled personnel. Costs of such
personnel are high and with the help of modern electronic technologies it is
more convenient to use devices that the patient can handle himself. Therefore
only some electronic sleep medicine devices remain in the hospital use.
The patient uses many different devices for diagnosing and cure of his
health with data being mostly transferred to the doctor via internet. In such
cases the patient will be surrounded with electronic body area networks and
smart home appliances such as electronic beds and pillows.
In conclusion it can be said that in the future the new electronic sleep
medicine devices will be more complex, smaller in size, easier to use and
cheaper to buy.
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Conference “Biomedical Engineering“
References
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5. Antonescu-Turcu A. and Parthasarathy S. CPAP and Bi-level PAP Therapy:
New and Established Roles // Respiratory Care, 2010, vol. 55, No. 9, Sept. P.1216–1229.
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Electronic means used in sleep medicine. A review
R. Kala
Member of Estonian Sleep Medicine Association, Estonia
Today's sleep medicine technology relies on electronics and therefore it is appropriate to talk about
electronical sleep medicine devices. Electronic sleep medicine technologies have evolved fast, and
have turned into a complex field of science. Today electronic devices have become so complex that
devices cannot be distinguished only by the working principle. Additional measures have to be
taken. Here a patient based approcah of classification of electronic sleep medicine devices is
presented.
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