POLYSMNOGRAPHY

1. POLYSMNOGRAPHY By Aida Mahmoud yousef

2. Polysomnography (PSG) : Is a multi-parametric test used in the study of sleep and as a diagnostic tool in sleep Medicine. The test result is called a polysomnogram,

3. Polysomnography is a comprehensive recording of the biophysiological changes that occur during sleep. It is usually performed at night, when most people sleep, but shift workers and people with circadian rhythm sleep disorderscan do the test at other times of day.

4. A single-night PSG is usually adequate. However, night-to-night variability may exist in patients who have a high probability but a low apnea index. • . So some authorities caution that more than one night of recording may be necessary so the patient can become comfortable with the surroundings and sleep more naturally.

5. The PSG monitors many body functions including brain (EEG), eye movements (EOG), muscle activity or skeletal muscle activation (EMG) and heart rhythm (ECG) during sleep. After the identification of the sleep disordersleep apnea in the 1970s, the breathing functions respiratory airflow and respiratory effort indicators were added along with peripheral pulse oximetry.

6. Full Polysomnography EEG EOG EMG ECG

8. Indications • Polysomnography is used to diagnose, or rule out, many types of sleep disorders It is often ordered for patients with complaints of daytime fatigue or sleepiness that may be caused by interrupted sleep.

9. Sleep Disorders • Obstructive • Central • Mixed • Upper airway resistance • Periodic Breathing • Narcolepsy • Insomnia • Periodic leg movement(PLM) • Restless legs • insomnia, sleep terrors

11. Any combination of twoor more of the following symptoms of sleep apnea {a. through e.}: • Excessive daytime sleepiness as evidenced by inappropriate daytime napping (e.g., during driving, conversation, or eating); sleepiness that interferes with daily activities not explained by other conditions, e.g., poor sleep hygiene, medication, drugs, alcohol, psychiatric or psychological disorders, or an Epworth Sleepiness Scale score greater than 10;  or • Persistent or frequent socially disruptive snoring or choking or gasping episodes associated with awakenings;  or

12. Symptoms suggesting narcolepsy, e.g., sleep paralysis, hypnagogic hallucinations, cataplexy; OR • Violent or injurious behavior during sleep; OR • Nocturnal oxygen desaturation with unexplained right heart failure, polycythemia, cardiac arrhythmias during sleep or pulmonary hypertension; OR • Excessive daytime sleepiness together with witnessed periodic limb movements of sleep. • Unexplained hypertension; or • Craniofacial or upper airway soft tissue abnormalities;  OR • neck circumference • Obesity (BMI greater than 30 kg/m²); or • .Witnessed apnea during sleep greater than 10 seconds in duration

13. Individuals with moderate or severe congestive heart failure, stroke/TIA, coronary artery disease, or significant tachycardic or bradycardic arrythymias who have nocturnal symptoms suggestive of a sleep apnea. • Any other unexplained symptoms associated with disruption of normal sleeping patterns that have persisted for 6 to 12 months

14.   The American Academy of Sleep Medicine (AASM) states that, "Adult patients with habitual snoring, excessive daytime sleepiness, a BMI greater than 35 and observed apneas are at high risk for OSA with at least a 75% likelihood of having an AHI (or RDI) equal to or greater than 10."  • "Berlin Questionnaire" with three groups of questions: one regarding snoring, the second regarding daytime sleepiness, and the third regarding the presence of hypertension or obesity. 

15. Repeat PSG for adults is considered medically necessary under the following circumstances: • To re-evaluate an individual with failure of resolution of symptoms or recurrence of symptoms during treatment; OR • To evaluate the impact of uvulopalatopharyngoplasty (UPPP) or other corrective surgeries for obstructive sleep apnea (OSA) • To evaluate the impact of an oral appliance • To titrate continuous positive airway pressure (CPAP)

16. using CPAP, if a significant weight loss has occurred since the initial study; OR • To titrate CPAP prescription when half night or "split night" PSG with titration of CPAP performed in the second part of the study is not possible due to AHI or RDI less than 20 or when initial PSG was not diagnostic in time to allow for at least 3 hours of CPAP titration including both REM and non-REM sleep.

18. Mechanism • A polysomnogram will typically record from eight to twelve channels requiring about 22 wire attachments to the patient. These channels vary in every lab and may be adapted to meet the doctor's requests.

19. Wires for each channel of recorded data lead from the patient and converge into a central box, which in turn is connected to a computer system for recording, storing and displaying the data. During sleep the computer monitor can display multiple channels continuously. In addition, most labs have a small video camera in the room so the technician can observe the patient visually from an adjacent room

22. (EEG) • The electroencephalogram (EEG) will generally use six "exploring" electrodes and two "reference" electrodes, unless a seizure disorder is suspected, • The exploring electrodes are usually attached to the scalp near the frontal, central (top) and occipital (back) portions of the brain via a paste that will conduct electrical signals originating from the neurons of the cortex.

23. One EEG channel (central channel with an ear reference provides the best amplitude) is used to monitor sleep stage. However, most laboratories use 2 central channels and 2 occipital channels, with ear references as an adjunct to help identify sleep latency and arousals. A 10- to 20-electrode placement system is used to determine the location of these channels. Additional EEG channels can be used, particularly in patients with epilepsy (ie, a full 10-20 montage).

28. These electrodes will provide a readout of the brain activity that can be "scored" into different stages of sleep (N1, N2, N3 which combined are referred to as NREM sleep, and Stage R which is rapid eye movement sleep or REM, and Wakefulness).

29. EOG • The electrooculogram (EOG) uses two electrodes; one that is placed 1 cm above the outer canthus of the right eye and one that is placed 1 cm below the outer canthus of the left eye. These electrodes pick up the activity of the eyes and the electropotential difference between the cornea and the retina (the cornea is positively charged relative to the retina). Evaluation of the eye movements is necessary for 2 reasons. First is for documentation of the onset of rapid eye movement (REM) sleep, and second is to note the presence of slow-rolling eye movements that usually accompany the onset of sleep.

33. Eye blinks: Conjugate vertical eye movements at a frequency of 0.5–2 Hz present in wakefulness. • Slow eye movements: Conjugate, fairly regular, sinusoidal eye movements with an initial deflection lasting > 500 msec. are typical of eyes closed drowsy, wakefulness, and stage N1 sleep. • Rapid eye movements (REMs): Conjugate, irregular, sharply peaked eye movements with an initial deflection usually lasting < 500 msec. Whereas rapid eye movements are characteristic of stage R sleep, they may also be seen in wakefulness with eyes open • Reading eye movements: Trains of conjugate eye movements consisting of a slow phase followed by a rapid phase in the opposite direction as the subject reads. due to a slow scan of the written page (left to right) followed by a rapid return to the left.

35. EMG • The electromyogram (EMG) typically uses four electrodes to measure muscle tension in the body as well as to monitor for an excessive amount of leg movements during sleep (which may be indicative of periodic limb movement disorder, PLMD).. This, like the EOG, helps determine when sleep occurs as well as REM sleep. Sleep generally includes relaxation and so a marked decrease in muscle tension occurs.

37. in REM sleep. A person becomes partially paralyzed to make acting out of dreams impossible, although people that do not have this paralysis can suffer from REM behavior disorder. • Two or more leads are placed on the anterior tibialis of each leg to measure leg movements. • To assess bruxism, the EMG electrodes can be placed over the masseter. • the intercostal EMG is used as adjunctive help for determining effort during respiratory events.

40. Though a typical electrocardiogram (ECG or EKG) would use ten electrodes, only two or three are used for a polysomnogram.. These can be analyzed for any abnormalities that might be indicative of an underlying heart pathology

41. Two channels are used for monitoring airflow. One thermistor channel (oral and/or nasal) is used to evaluate the presence or absence of airflow. Thermistor is the recommended channel for evaluation of apneas. • Nasal pressure transducer channel is a more sensitive measure of airflow restriction( hypopneas ,airflow resistance in upper airway resistance syndrome).

42. Normal breathing has a rounded pattern, while resistance to airflow leads to a squaring off of the flow signal,This forces air in and out of the mouth while no air enters the airway and lungs. Thus, the pressure transducer and thermocouple will detect this diminished airflow and the respiratory event may be falsely identified as a hypopnea, or a period of reduced airflow, instead of an obstructive apnea.

43. Other parameters that can be monitored in a sleep study include the following: • Pulse oximetry • End tidal or transcutaneous CO2 • Sound recordings to measure snoring • Continuous video monitoring • Sleep position

44. Optional parameters that can be monitored in a sleep study include the following: • Core body temperature • Pressure and pH at various esophageal levels

46. Pulse oximetry determines changes in blood oxygen levels that often occur with sleep apnea and other respiratory problems. The pulse oximeter fits over a finger tip or an ear lobe.

47. snoring • may be recorded with a sound probe over the neck, though more commonly the sleep technician will just note snoring as "mild", "moderate" or "loud" or give a numerical estimate on a scale of 1 to 10. • Also, snoring indicates airflow and can be used during hypopneas to determine whether the hypopnea may be an obstructive apnea

49. instructions • Maintain regular sleep-wake rhythm. • Alcohol and sleeping pills may alter the PSG results, but if they are part of the patient's normal routine, they should not be abruptly stopped. • Avoid stimulants, including medications for narcolepsy. • Avoid strenuous exercise on the day of the PSG. • Avoid naps on the day of the sleep study.

50. Stimulant medications, nicotine, and caffeine can affect the mean sleep latency, and medications (especially selective serotonin reuptake inhibitors [SSRIs]) can affect sleep-onset rapid eye movement (REM) periods.[3] In general, SSRIs and stimulants need to be discontinued at least 2 weeks prior to the test. Small amounts of caffeine do not usually need to be discontinued.