In medicine, compliance describes the degree to which a patient correctly follows medical advice. Most commonly, it refers to medication or drug compliance, but it can also apply to other situations such as medical device use, self care, self-directed exercises, or therapy sessions. Worldwide, non-compliance is a major obstacle to the effective delivery of health care. Estimates from the World Health Organization (2003) indicate that only about 50% of patients with chronic diseases living in developed countries follow treatment recommendations.
Methods and apparatus are described for determining sleep disorder appliance compliance. Embodiments include receiving, in a sleep disorder compliance module through one or more sensors of an earpiece worn within an ear of a sleeping patient, information regarding the sleep of the patient; deriving, by the sleep disorder compliance module from the information regarding the sleep of the patient, one or more biometric values capable of indicating whether the patient is using a sleep disorder appliance; and determining, by the sleep disorder compliance module, whether the one or more biometric values indicate that the sleeping patient is presently using the sleep disorder appliance.
The foregoing and other objects, features, and advantages of the invention will be apparent from the following more detailed descriptions of example embodiments as illustrated in the accompanying drawings. In the drawings, like reference numbers generally represent like parts of example embodiments.
Example methods and apparatus or systems for determining sleep disorder appliance compliance are described with reference to the accompanying drawings, beginning with
The earpiece (204) in this example is manufactured from a 3D image derived from an optical scan of the interior of the patient's ear canal. Creating a 3D image derived from an optical scan of the interior of the patient's ear canal can be carried out using methods and systems described in U.S. patent application Ser. Nos. 13/417,649; 13/417,767, 13/586,471; 13/586,411; 13/586,459; 13/546,448; 13/586,448; 13/586,474; 14/040,973, 14/041,943; 14/049,666; 14/049,530; 14/049,687, all incorporated by reference herein in their entirety.
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Appliance compliance determinations are carried out generally in embodiments by use of electroencephalography (‘EEG’), electromyography (‘EMG’) and electrooculography (‘EOG’) information from sensors on an earpiece within the ear. The stage of sleep typically is taken from EEG and EMG information, from measures of the power of signals at certain frequencies. Stage 2 sleep will give sudden, short high-voltage wave bursts occurring at 12-14 Hz. Stage 3 sleep will show theta (4-7 Hz) and delta waves (1-4 Hz) with skeletal muscles very relaxed. Stage 4 is “slow wave sleep” because of delta waves, with a body turn approximately every 20 minutes. Rapid eye movement (‘REM’) sleep is indicated after the first four stages when frequency goes back to alpha waves, body temperature increases, heart rate increases, respiratory rate increases, blood pressure increases, the brain uses even more oxygen than when awake, eyes move rapidly. This particular signal from eye movement may be classified as EMG rather than EOG and is easily detected with information from the earpiece sensors.
Regarding REM sleep, sleep alternates between REM and non-REM or NREM; REM occurs about every 90 minutes and increases in length from 5-10 minutes to 20-50 minutes. The amount of REM sleep typically is determined in embodiments from sensor information by detecting eye movement using EOG and EMG. A person feels most rested when awakened just after a REM cycle, so that warnings can signal a person to awaken when apparatus in embodiments detects that REM is finished.
Clenching and grinding of teeth is detected in embodiments by use of EMG. For each skeletal muscle, there is an optimal longitudinal length at which the maximum muscle activation can occur; muscle activation of the muscles of mastication can be measured using EMG. When placing a sleep disorder appliance into the mouth, the teeth become separated, slightly lengthening the muscles of mastication, preventing the electrical signal from the muscles of mastication from being as intense as having no teeth separation. For a patient that is prone to clenching, the clenching intensity will be decreased when wearing the oral appliance. Warnings to the patient in embodiments effectively implements relaxation training. Some embodiments play music or tones only when a patient is relaxed (or vice versa) using EMG detection of nearby muscle activity (muscles of mastication).
Accelerometry from within the ear includes in embodiments nine degrees of freedom (9DOF accelerometry). 9DOF accelerometry includes multiple axes of detection from which, based on acceleration due to gravity, a patient's resting head position can be determined. Then embodiments can alert the patient to changes into nonoptimal sleep positions.
Oximetry typically is implemented as reflection pulse oximetry from within the ear or transmission pulse oximetry around the pinna. Embodiments can use both red (600-750 nm) and infrared light (850-1000 nm) to illuminate blood and use a photosensor to measure either transmission or reflection. Red light at 660 nm reflects off of hemoglobin when it is saturated (HbO2) and infrared light at 940 nm reflects off of de-oxygenated hemoglobin (Hb).
The ‘ratio of ratios’ according to Formula 1 is calibrated in embodiments to determine peripheral capillary oxygen saturation or SpO2 in percentage, using a lookup table to determine the actual percentage. SpO2 (%) can be measured, a value that decreases during an apneic episode. Pulse rate (beats per minute) can be measured in embodiments with oximetry because there is variable light absorption due to pulsatile volume of arterial blood. When measuring from within the ear canal, direct reflective pulse oximetry towards the superficial temporal artery, which runs anterior to the canal, or associated vasculature. When measuring in locations requiring light transmission detection (instead of reflection), such as through the pinna or ear lobe, embodiments use a clip that places lights on one side of tissue and photosensor on the other side. While using an oral appliance for obstructive sleep apnea, there are no acute decreases in oxygen saturation unless sleep apnea occurs via central sleep apnea where there is no respiratory effort by the patient. Embodiments therefore can alert a patient when oxygen saturation decreases below a threshold.
Sensors in embodiments can include a microphone to sense or record snoring sounds. Snoring sounds decrease with use of an obstructive sleep apnea oral appliance. Snoring sounds can also be used to indicate oral appliance (mandibular advancement appliance) effectiveness at maintaining pharyngeal patency. Audio from snoring in embodiments can complement accelerometer information to determine patient movements during sleep, alerting a patient to change positions when snoring indicates nonoptimal body position.
Additional warning-type technology in embodiments can include a speaker or earphone integrated in the earpiece that delivers information directly into a patient's ear without disrupting others nearby. Audible warnings can include alerts to change sleeping position, alerts to wake a patient, music or relaxation sounds, including playing slow breathing sounds for breath matching, to aid a patient in falling asleep. These alerts and sounds in embodiments are implemented with a phone paired via Bluetooth with a source of soothing sounds or music and, in some embodiments, are supportive of sleep-related training such as EMG relaxation training.
An embodiment includes a Piezo sensor to detect pulse from within the ear. This is in addition to pulse oximetry which in some embodiments may have too low measurement/calculation frequency or too low noise for pulse detection. A Piezo sensor is mounted on the earpiece so as to contact skin in the ear canal and detect pulse through impulses affecting skin pressure on the sensor. In at least one embodiment, skin pressure noise from snoring, movement, and the like, is canceled with audio noise from a microphone.
In some embodiments, earpiece sensors can include one or more active in-ear readers for sensors mounted on an oral appliance and directed to sleep disorder appliance compliance, including a passive RadioFrequency Identification (RFID) tag, a Near Field Communications (‘NFC’) tag, a contactless smart card, or the like, attached to the oral appliance and registered with the active in-ear reader in an earpiece when in use to determine appliance compliance. A passive tag in an embodiment is switched on only when the oral appliance is locked into the patient's mouth, working only when two pieces of the RFID tag are connected to each other via electrodes to the gums. One part of such an RFID tag is attached to the patient, making electrical contact to a second part of the RFID tag mounted on the oral appliance only when the appliance is worn. In another embodiment, a passive RFID tag is split into two parts as an open circuit, and the act of placing the oral appliance in the mouth and pressing it onto the teeth mechanically connects the two for further operation with an active RFID reader.
The active in-ear reader in the earpiece sends an RF signal to power a passive RFID or NFC tag installed on the oral appliance. The active in-ear reader can send an RF signal that powers a passive tag on the oral appliance, with the passive tag connected to one or more physiological sensors, temperature, O2, pressure against teeth, electrical conduction, and so on, with the sensor data then sent back to the active reader in the ear. A force sensor may be embedded in an oral appliance to be pressed against tooth during use, with force data be transferred to the in-ear reader to determine appliance compliance. A temperature sensor may be embedded into an oral appliance, with temperature data transferred to the in-ear reader to determine appliance compliance.
In some embodiments, an oral appliance contains a piezo or bone conduction transducer, with audio vibrations received by microphone in the ear or on the appliance, with a connection to the earpiece by RFID, ultrasound, vibration, and so on. An ultrasound signal in such embodiments is sent from the ear device through the body and makes contact with the oral appliance. The signal is then passively modulated and reflected through the body and back to the ear device. The modified signal received by the ear device confirms proper placement of the oral appliance in the mouth.
Because a specific ear canal geometry exists with each jaw position, and an appliance such as a mandibular advancement oral appliance significantly changes jaw position, embodiments can determine whether a patient is wearing an oral appliance by analyzing the shape of the ear canal. Apparatus for appliance compliance monitoring can be configured to scan the ear while the patient wears the oral appliance, with several force sensors placed around the shell of the appliance. The force values associated with placement of the oral appliance are calibrated per patient and per appliance. In some embodiments the force sensors are capacitive touch sensors rather than force sensors as such, although persons of skill in the art may think of other kinds of sensors. Such embodiments also encourage use of the ear device while wearing the oral appliance because the best fit will be obtained in the ear canal when wearing the oral appliance. Jaw position associated with not wearing the oral appliance would throw off contact of at least one of the EEG/EMG/EOG electrodes with the skin—if so, this would be determined from the sensed information and/or biometric values.
Also in some embodiments, appliance compliance is measured by aiming ultrasound toward the mandibular condyle from within the ear, from a transducer in the earpiece. The distance to the condyle corresponds with use of the oral appliance and is calibrated per patient and per appliance.
It will be understood from the foregoing description that modifications and changes may be made in various embodiments of the present invention without departing from its true spirit. The descriptions in this specification are for purposes of illustration only and are not to be construed in a limiting sense. The scope of the present invention is limited only by the language of the following claims.