智慧電子整合性人才培育先導型計畫 教材成果研習會 計畫主題：智慧電子應用技術平台醫療電子應用設計專題
2012 智慧電子應用設計聯盟成果展 醫療電子應用設計專題 Advisior : Evans Lee
Lesson 1. To sleep, or not to sleep, that is the question!
Outline • 1-1. Introduction • 1-2. Related Work • 1-3. REM vs. NREM • 1-4. Comparison of REM & NREM • 1-5. staging of sleep • 1-6. parameters for staging • 1-7. parameters for sleep study
1-1. Introduction (Sleep study)(5/7) • During a sleep study the sleep cycles and stages of sleep are monitored. • Electrodes are placed to monitor continuousrecordings of brain waves, electrical activity of muscles, eye movement, respiratory rate, blood pressure, blood oxygen saturation, and heart rhythm. • The test (PSG) is performed for people who suffer from insomnia, excessive daytime sleepiness, obstructive sleep apnea, breathing difficulties during sleep, or behavior disturbances during sleep.
Percentage of Adult 25 % Sleep Disorder 1-1. Introduction (Sleep Disorder)(6/7) • Sleep Disorder • Insomnia, Narcolepsy, Obstructive Sleep Apnea… • A lack of restorative rest can cause accidents on the job or on the road, affect your relationships, health, and mental prowess.
1-1. Introduction (Sleep Disorder)(7/7) • Sleep Disorder Index • Empiricism • Sleep Scale • Epworth Sleepiness Scale, ESS • Adaptation of Functional Outcomes of Sleep Questionnaire, FOSQ • Pittsburgh Sleep Quality Index, PSQI • Measurement Instruments • Polysomnogram, PSG
1-3. REM vs. NREM • There are two states of sleep: • NREM (non-rapid eye movement) REM sleep is associated with dreaming andparalysis of body muscles (except for the eye and diaphragm muscles). • REM (rapid eye movement ) NREM sleep has four stages distinguishable by EEG waves. A person with normal sleep usually has four to five cycles of REM and NREM sleep during a night.
1-5. staging of sleep • Sleepstaging was scored according to the criteria of Rechtschaffen and Kales. • Arousals were scored as defined in the American Sleep Disorders Association Atlas Task Force report on EEG arousals. • The arousal index is defined as the number of cortical arousals per hour of sleep (each ≧3 s). • The awakening index is defined as the number of cortical awakenings per hour of sleep (each ≧ 15 s). • The sleep disturbance index is defined as the sum of the arousal index plus the awakening index.
1-6. parameters for staging • Sleep staging depends on : 1. EEG(Electroencephalogram): brain activity 2. EOG(Electroocculogram): eye movement 3. EMG(Electromyogram): muscle tone
1-7-1. Electroencephalogram • Six electrodes (labeled C3, C4, A1, A2 O1, and O2) and one ground electrode are placed around the cranium to record electrical activity across the brain. • These leads are used to determine the stage of sleep the patient is in during any given period of the night.
1-7-2. Electroocculogram • One electrode is placed above and to the outside of the right eye, and another electrode is placed below and to the outside of the left eye. • These leads record the movements of the eyes during sleep and serve to help determine sleep stages.
1-7-3. Electromyogram • Three leads are placed on the chin (one in the front and center and the other two underneath and on the jawbone) and two are placed on the inside of each calf muscle 2-4cm apart. • These leads serve to demonstrate muscle movement during sleep. This is helpful in documenting a wake period, an arousal, or just a spastic movement.
1-7-4. ECG and flow detector • Two electrodes are placed on the upper chest near the right and left arms. These record the heart rate and rhythm and serve to alert the technician to a possible emergency situation. They also demonstrate whether apneic desaturation leads to arrhythmias or not. • It senses the amount of air moving into and out of the airways and sends a signal to a physiological recorder. This tracing is used to determine the presence and extent of apneic episodes.
1-7-5. Pulse oximetry • The O2 saturation is measured by a pulse oximeter probe placed on the patient i.e. finger, earlobe, etc.
1-7-6. Respiratory Effort • Two Velcro bands, one placed around the chest under the breasts and one around the abdomen, serve to determine chest wall and abdominal movements during breathing. Each band is joined together by a piezo crystal transducer. • The force of chest/abdominal expansion on the bands stretches the transducer and alters the signal to a physiological recorder. These leads, combined with the airflow sensor, are how apnea is demonstrated and categorized during the test.
1-7-7. Video recording • If the sleep disorders center is equipped with video cameras in the patient rooms, the patient can be taped while sleeping. • This allows the technician to review the tape at any time during the test and verify whether strange looking waveforms were caused by an actual arousal, a period of wake, or normal patient movement in bed.
1-8-1. Polysomnography(1/3) • PSG is a comprehensive recording of the biophysiological changes during sleep. • Used to diagnosesleeping disorders including narcolepsy, REM behavior disorder, parasomnias, and sleep apnea.
1-8-1. Polysomnography(2/3) • Sleeping stage estimation • EX:ECG,EOG • Physical activity monitoring • EX:EMG,body position • Breathing monitoring • EX:Snore,nose stream,SpO2
1-8-1. Polysomnography(3/3) • After the test is completed a "scorer" analyzes the data by reviewing the study in 30 second "epochs“ • Cardiac rhythm abnormalities. • Leg movements. • Body position during sleep. • Oxygen saturation during sleep.
Lesson 4. Design and Implementation of PortableMonitoring Device for Sleep Quality Evaluation
Outline • 4-1. Motivation • 4-2. System Architecture • 1.Signal Processing • 2.Classification • 4-3. Experiments • 4-4. Implementation Results • 4-5. Conclusions
Expensive Gold Standard Operation Complex PSG Attach Electrodes One Night Monitor 4-1. Motivation
Expensive Gold Standard Operation Complex PSG Attach Electrodes One Night Monitor 4-1. Motivation Low Cost Easy to Use Pre-Screening Home Device Unnecessary Attach Long-Term Monitor
4-1. System Architecture(1/4) • System Overview • Testee • Sensors Personal Computer • I/O devices Sleep or Wake Algorithms • Computer Deep Sleep or Light Sleep Sleep Efficiency Sleep latency
4-1. System Architecture(3/4) • Hardware system architecture
4-1. System Architecture(4/4) • Processing • Signals Processing • Classification
4-1. System • MSP430F1611 SOC System • PPG Device • Tri-axis Accelerometers
MSP430F1611 SOC System Photo Source:www.Ti.com
PPG Device(Pulse Oximetry ) This Sleep Monitor Device used a PPG Device which produced by Nonin Company to measure Pulse Oximeter signal
PPG Output Status • Packet Description • A frame consists of 5 bytes; a packet consists of 25 frames. • Three packets (75 frames) are transmitted each second
PPG Output Status Byte 1 : Start Byte(Always set to a 01 value) Byte2 : Status Byte (This byte provides status information at a rate of 1/75 of a second) Byte3 : PLETH Byte This byte consists of an 8 bit plethysmographic waveform (pulse waveform) Byte4 : FLAT Byte This byte is used for SpO2, Pulse Rate, and information that can be processed at a rate of 1/3 of a second Byte5 : Check Byte (This byte is used for the checksum of bytes 1 through 4) CHK = (Byte 1 + Byte 2 +Byte 3 +Byte 4) mod 256 Xpod Packet output format Source:www.nonin.com
PPG Output Status Source:www.nonin.com
Tri-axis Accelerometers(1/8)(LIS344ALH) Key Features (1.)2.4 V to 3.6 V single supply operation (2.)±2 g / ±6 g user selectable full-scale (3.)Low power consumption (4.)Output voltage, offset and sensitivity are ratiometric to the supply voltage (5.)Factory trimmed device sensitivity and offset (6.)Embedded self test (7.)RoHS/ECOPACK® compliant (8.)High shock survivability ( 10000 g )
Tri-axis Accelerometers(3/8) The relationship between Cload and cut-off frequency
Tri-axis Accelerometers (6/8) Position of LIS344ALH and corresponding output voltage