Polysomnography

Polysomnography
Presenter : Dr. Saran A K
Preceptors : Dr. Kamlesh Jha and Dr. Ganashree C. P
DM Seminar | 13 October 2023
DEPT. OF PHYSIOLOGY, AIIMS PATNA 2

Overview
● Case Vignette
● Indication and Types
● Digital and Technical Specifications
● Recommended Parameters
● Scoring of Sleep Events
● Summary
5

Overview
● Case Vignette
● Summary
6

Case History
Mr. X, a 55-year-old male complaints of excessive day time
sleepiness for the past 6 months. He has associated increase in
body weight of 5 kgs during this period.

Components of a good sleep history?
1. Sleep timings – hours, day-time naps?
2. Normal sleeping habits – time in/out, arousal
3. Sleep quality – refreshed after sleep?
4. Snoring – frequency/loudness/ position
5. Apneic Event – choking?
6. Abnormal behavior during sleep – limb movements?
7. Daytime functioning

8. Personal Habits – alcohol, tobacco, stimulants?
9. Medical History –thyroid, stroke/epilepsy, heart diseases,
hypertension, diabetes, asthma, deviated nasal septum,
depression or other psychiatric illness
10. Drug History – all medications including sedatives,
antidepressants and anxiolytics
11. Occupational History – stress/ work timing/time zone change
12. Social History

• He admits that he has been sleepier as of late
• Fallen asleep during meetings - snoring
• Goes to bed around 11pm, falls asleep quickly, but may wake up
several times throughout the night.
• Wakes up at 7 am to get ready for work - drag himself out of bed
• Early morning headaches.
• He tries to catch up during the weekends by taking afternoon naps.
• He drinks 2 cups of coffee in the morning and several caffeinated
sodas throughout the day.

• His wife mentions that he has been more tired lately when he
comes home from work and has trouble concentrating on tasks.
• He has dozed off in front of the TV while waiting for dinner.
• He has restless sleep during the night, and she is getting tired of
having her own sleep disrupted with his loud snores.
• He does little else but sleep during the weekend.

Assessment of Sleep
• Prospective Self Report : Sleep wake diaries or sleep logs

Assessment of Sleep
• Prospective Self Report : Sleep wake diaries or sleep logs
• Retrospective self report
• Pittsburg Sleep Quality Index (Buysse et. al. 1989)
• Epsworth Sleepiness Scale (Johns, 1991)
• Insomnia Severity Scale (Bastien et. al. 2001)
• Berlin Sleep Apnea Questionnaire (Netzer et. Al. 1999)

Components of a good sleep physical examination
1. Obesity - Body Mass Index
2. Neck Circumference
3. Enlarged Tonsils
4. Larger Tongue
5. High arched hard palate
6. Facial abnormalities (retrognathia or micrognathia)

Modified Mallampati Score

Epworth sleepiness score (ESS) is 12 out of 24.
His physical exam is remarkable for
• Blood pressure of 150/70
• Oxygen saturation of 95% on room air
• Body mass index of 35 kg/m2
• Mallampati score III
• High arched palate
• Neck size 17.5 inches (44.5 cm)

Diagnostic Criteria OSA – ICSD 3

Polysomnography
It is the continuous monitoring and
simultaneous recording of the physiological
activities during sleep.

Simultaneous recording of
• Sleep Staging
• Eye Movements
• Electromyographic Tone
• Respiratory Parameters
• Electrocardiogram

Overview
● Case Vignette
● Summary
21

Overview
● Case Vignette
● Summary
22

Routine indications – PSG
1. Diagnosis of sleep related breathing disorders (SRBDs)
2. Positive airway pressure titration in patients with SRBDs
3. Assessment of treatment results
4. With Multiple Sleep Latency Test (MSLT) in evaluation of suspected
narcolepsy.
5. Evaluating SRBDs that are violent or otherwise potentially injurious to
patients and others
6. Atypical or unusual parasomnias

Patient instructions - AASM
1. Follow your regular routine as much as possible
2. Avoid napping day before the study
3. Avoid caffeine after lunch
4. Avoid using hair sprays or gels that can interfere with the sleep
recording
5. Avoid alcohol or other sedatives unless otherwise prescribed by
your doctor.
6. Comfortable clothes to sleep in, cotton clothes preferred

Types of monitors
Types
Type I In laboratory, technologist attending PSG
Usual channels : EEG, EOG, chin EMG, ECG, airflow, respiratory
effort and Spo2 (minimum of 7 channels as per AASM criteria)
Type II Unattended polysomnography (minimum of 7 channels, as above)
Type III Portable monitoring with minimum of 4 channels, including
respiratory movement, airflow, heart rate, SpO2
Type IV Portable monitoring with only one or two channels, including
pulse oximetry

Overview
● Case Vignette
● Summary
26

Overview
● Case Vignette
● Summary
27

Digital Specifications for PSG (AASM)

Overview
● Case Vignette
● Summary
29

Overview
● Case Vignette
● Summary
30

Recommended parameters to be reported

Arch Dis Child Educ Pract Ed. 2020 Jun;105(3):130-135

1. Electroencephalogram
• International 10-20 System.
• A minimum of 3 EEG derivations are required - frontal, central and
occipital regions.
• M1 and M2 refer to the left and right mastoid process.
• The recommended derivations are F4-M1, C4-M1 and O2-M1
• Backup electrodes should be placed at F3, C3, O1 and M2.

The AASM manual for the scoring of sleep and associated events,2018

2. Electrooculogram
Recording of the movement of the corneo‐retinal potential
difference, not the movement of eye muscle.

The recommended EOG derivations are E1-M2 (E1 is placed 1cm
below the left outer canthus) and E2-M2 (E2 is placed 1 cm above
the right outer canthus)
Right out and up / Left out and down
E1
E2

Eye movement patterns
Fundamentals of sleep medicine

3. Chin Electromyogram
A- Reduction in chin EMG
C- Rapid eye movements

4. Electrocardiogram
Single modified
lead II electrode
and torso electrode

5. Leg Electromyogram
Tibialis anterior
Extensor digitorum superficialis Extensor digitorum communis

6. Respiratory Flow
• Important signal to score apnea and
hypopnea.
• It is measured using a thermistor and a
pressure transducer
• The thermistor is important for the
diagnosis of apnea while a pressure
transducer helps in recognizing hypopnea

7. Respiratory Effort
• Important for differentiating between
obstructive and central respiratory events
(both apneas and hypopneas).
• RIP belts are considered superior and
are recommended.

8. Oxygen Saturation
Pulse oximeter that provides a SpO2
average of 3 seconds values.

Other sensors
9. Body position
10.Synchronized PSG Video

Overview
● Case Vignette
● Summary
48

Overview
● Case Vignette
● Summary
49

SLOW WAVE SLEEP
OR
DEEP SLEEP
50

• Sleep Staging
• Score sleep stages in 30s, sequential epoch commencing at the start
of the study – EMG, EEG and EOG
• Assign a stage to each of the epoch
• If 2 or more stages coexist during a single epoch, assign the stage
comprising the greatest portion of the epoch.
• Respiratory events- 2min / 5min epoch
• EEG arousals- 30s epoch

Wakefulness – W (Eyes open)
EEG → high-frequency, low-voltage activity (chiefly beta and alpha
frequencies) without the rhythmicity of alpha rhythm ⇒ indicative of
the unique activity of individual cortical neurons
EOG → Rapid eye movements (initial deflection is less than 500ms)
and eye blinks (vertical movements 0.5–2 Hz), Reading eye
movements
EMG → Chin EMG relatively increased compared with that during
sleep - high-frequency activity
54
DEPT. OF PHYSIOLOGY, AIIMS PATNA

Wakefulness –W (Eyes closed)
● EEG → Rhythmic waves in the alpha range (8–13 Hz),
particularly over the occipital region
● EOG → Slow eye movements (SEMs) may be present
● EMG → Chin EMG activity is variable and relatively high

Drowsy (before sleep onset) alpha waves, seen in EEG leads (red rectangle), occupy greater than 50% of the 30-second
epoch
Otolaryngol Clin North Am. 2016 Dec;49(6):1307-1329

• Transition phase includes Alpha rhythm and Low Amplitude
Mixed Frequency waves (LAMF) with SEMs
• Time with the patient disconnected from the recording
equipment should be scored as Stage W.
• Brief episodes of sleep during this time are not considered
significant for stage scoring summary.

N1
• Consciousness begins to fade, but the individual may still be awakened
by minimal stimulation
• EEG → slows and shows low-amplitude mixed-frequency (LAMF) activity
(4-7 Hz) activity (more than 50% of epoch) + absence of sleep
spindles (SSs) and K complexes (KCs) not associated with arousal
• EOG → Slow roving eye movements
• EMG → less activity

N2
• Sleep deepens and there is a further lack of sensitivity to
activation and arousal
• EEG- Low Amplitude Mixed Frequency (LAMF) - Slow activity in
the theta (0.5−4 Hz)
• EOG– Occasionally SEMs near sleep onset
• EMG – Tonic activity, low level

Sleep Spindle: A train of distinct waves with frequency 11-16 Hz
with a duration of ≥ 0.5 seconds usually maximal in amplitude
using central derivations

K Complex: A well delineated negative sharp wave immediately
followed by a positive component standing out from the
background EEG, with total duration ≥ 5 seconds, usually
maximal in amplitude when recorded using frontal derivations

N3
• Deep sleep - Activation and arousal occurs only if stimulus is
strong When awakened, does not report of dreams
• EEG
• Abundant, high-voltage very slow delta waves → slow
wave activity (delta 0.5-4 Hz) , ≥ 20% of epoch
• Chin EMG → variable, low level
• EOG – None, picks up EEG

R
• EEG
• Rapid, low voltage waves resembling alert, awake state
• Without KCs and SS
• As brain is highly active → metabolism increased by 20% -
Paradoxical
• Ponto Geniculo-occipital spikes (PGO) spikes
• EOG → rapid eye movements
• EMG → low chin EMG tone (activity)

Arch Dis Child 2009; 94:63–69.
Hypnogram

Arousal
• An arousal is a brief awakening from sleep that lasts at least 3
seconds.
• Apnea and hypopnea events often cause arousals from
sleep.

Apnea
• Drop in peak signal
excursion by ≥ 90% of
pre- event baseline
using an oronasal
thermal sensor
• Duration of ≥ 90%
drop in sensor signal
lasts ≥10 seconds

Fundamentals of sleep medicine
Central sleep apnea
Obstructive sleep apnea
Mixed sleep apnea

Score an apnea as an obstructive apnea if:
• it meets apnea criteria and
• is associated with continued or increased inspiratory effort
throughout the entire period of absent airflow.
Score an apnea as a central apnea if:
• is associated with absent inspiratory effort throughout the entire
period of absent airflow.
Score an apnea as a mixed apnea if :
• is associated with absent inspiratory effort in the initial part of the
event, followed by resumption of inspiratory effort in the second
part of the event.

Hypopnea
Score a respiratory event as a hypopnea if all of the following criteria
are met:
• The peak signal excursions drop by ≥ 30% of pre-event baseline
using nasal pressure
• The duration of ≥30% drop in signal excursion is 10 seconds.
• There is a ≥3% desaturation from the pre-event baseline or the
event is associated with an arousal.

AHI (Apnea Hypopnea Index)
The AHI refers to the total number of apnea and hypopnea events that occur
each hour of sleep - severity of sleep apnoea
• 0-5 apnoea + hypopnoea events per hour = normal
• 6-15 apnoea + hypopnoea events per hour = mild sleep apnoea
• 16-29 apnoea + hypopnoea events per hour = moderate sleep apnoea
• 30 or greater apnoea + hypopnoea events per hour = severe sleep
apnoea

Critical limb movements
Placement of electrodes on anterior tibialis muscle for monitoring limb
movements
Movements + muscle artefact obscuring the EEG for more than half
of each epoch to the extent that sleep stage cannot be determined
Major Body movements

Hypnogram
• Compressed graphic summary of entire sleep study
• Representation of multiple variables :
• Sleep stages
• Respiratory events
• Positive airway pressure (if used)
• Motor movements
• Oximetry
• End-tidal or transcutaneous CO2,
• Heart rate variability measures
• Electroencephalographic power spectrum
• Body position
Atlas of sleep medicine

Sample PSG report

55 M c/o excessive day time sleepiness, disturbed sleep, early morning headaches,
snoring with increase of body weight during the last 6 months. Epsworth Sleep
Score 12/24, BMI 35 kg/m2, Malampatti score III, Neck circumference 44 cm

Overview
● Case Vignette
● Summary
88

Overview
● Case Vignette
● Summary
89

Parameter Sensors Purpose
Electroencephalography Frontal, central, occipital leads
with mastoid process reference
lead
Stage sleep, detect epileptiform activity
Electrooculography Outer canthi leads with mastoid
process reference lead
Stage sleep (specifically stage R)
Electromyography Submental surface electrodes,
Anterior tibial surface electrodes
Stage sleep (specifically stage R), detect
REM without atonia, detect periodic limb
movements and other movement
abnormalities
Airflow Nasal cannula
pressure transducer
Oronasal thermal
sensor
PAP device (titration study)
Detection of hypopneas
Detection of apneas
Otolaryngol Clin North Am. 2020 Jun;53(3):367-383
Summary

Respiratory effort Chest and abdomen respiratory
inductance plethysmography
belts
Classify respiratory events as
obstructive, central, or mixed
Snoring Microphone, piezoelectric sensor Detect snoring
Arterial
oxygen
saturation
Pulse oximetry Detect hypoxemia
Electrocardiogram Modified lead II Monitor cardiac rate and rhythm
Position Accelerometer, video monitors Detect position
Behaviour Audio, video monitors Detect parasomnias, abnormal behaviors,
seizures
Otolaryngol Clin North Am. 2020 Jun;53(3):367-383

References
1. AASM Manual V 3.0 for the scoring of sleep and associated events, 2023
2. Kryger, M. H., Roth, T., Goldstein, C. A. Kryger's Principles and Practice of Sleep
Medicine, Seventh Edition. Netherlands: Elsevier Health Sciences. 2021
3. Berry, R. B. Fundamentals of Sleep Medicine. United Kingdom: Elsevier
Health Sciences. 2011
4. Kandel, E. R., Principles of Neural Science, Sixth Edition. Greece: McGraw-
Hill Education. 2021
5. Barrett, D. K. E., Barman, S. M., Yuan, J., Brooks, H. L. Ganong's Review of Medical
Physiology, Twenty Sixth Edition. United States: McGraw Hill LLC. 2019
6. Hall, J. E. Guyton and Hall Textbook of Medical Physiology, 14th Edition. United
Kingdom: Elsevier Health Sciences. 2021

THANK YOU !
saran.adhoc@gmail.com

Overview
● Case Vignette
● Summary
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Overview
● Case Vignette
● Summary
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