PSG

Question 1

What does the PSG give information on (4)

Answer 1

Duration/amount of sleep
Patterns of sleep
Quality of sleep
Behaviours during sleep

PSG is an overnight study recording physiological information about sleep.

Question 2

What is the purpose of Polysomnography (PSG)?

Answer 2

Measures physiological data during sleep and wake overnight

Provides information on duration, patterns, quality of sleep, and behaviors during sleep.

Question 3

Which sleep disorder requires PSG with MSLT performed the next day for evaluation?

Answer 3

Narcolepsy

PSG is routinely indicated in the evaluation of suspected narcolepsy.

Question 4

What type of PSG is indicated when clinical evaluation and standard EEG are inconclusive for nocturnal seizures?

Answer 4

PSG with extended EEG, TA EMG, and Video

This approach helps in diagnosing nocturnal seizures.

Question 5

For which condition is PSG indicated in unusual or atypical sleep behaviors?

Answer 5

Parasomnias

PSG is used to evaluate unusual sleep behaviors.

Question 6

What does PSG measure regarding respiratory events?

Answer 6

• Nasal airflow
• Respiratory effort bands
• Pulse oximetry
• Snoring
• Leg movements
• ECG
• Video monitoring

These measures help assess respiratory function during sleep.

Question 7

What is the First night effect in PSG?

Answer 7

A phenomenon where the first night of monitoring may yield different results than subsequent nights

This can affect the accuracy of sleep data.

Question 8

What should patients be asked about prior to PSG?

Answer 8

• Smoking history
• Unusual events during the day
• Alcohol and caffeine intake
• Sleep history in the last 24 hours
• Current medication

These factors can influence sleep quality and PSG results.

Question 9

What is the recommended standard for scoring sleep stages and arousals in PSG?

Answer 9

Based on unit of 30 sec epoch

Each epoch must be assessed as a whole for its sleep stage.

Question 10

What characterizes Stage 1 sleep in PSG scoring?

Answer 10

Theta activity on EEG, lateral eye movements, decrease in EMG

This stage marks the transition from wakefulness to sleep.

Question 11

What is the AASM definition of hypopnoea?

Answer 11

Reduction in airflow of over 30% for more than ten seconds, with a 4% or more reduction in oxygen saturation

Hypopnoea is scored using nasal pressure cannula.

Question 12

What is the AASM definition of obstructive apnoea?

Answer 12

Over 90% reduction in airflow for over ten seconds, with respiratory effort still visible

This indicates an obstructive event during sleep.

Question 13

What is the AASM definition of central apnoea?

Answer 13

over 90% in airflow for over ten seconds, no respiratory effort or movement on respiratory belts.

Question 14

What does PLMI stand for in PSG reporting?

Answer 14

Periodic Limb Movement Index

PLMI quantifies limb movements during sleep.

Question 15

What is measured by pulse oximetry during PSG?

Answer 15

Presence, duration, and severity of oxygen desaturations

Normal ranges for patients without pulmonary pathology are from 95 to 99 percent.

Question 16

What is the significance of video monitoring in PSG?

Answer 16

Widely used method to monitor respiration and diagnose sleep apnoea

It helps correlate respiratory events with physical movements.

Question 17

What is the AASM definition of an EEG arousal?

Answer 17

Abrupt shift in EEG frequency lasting >3 seconds, preceded by >10 sec stable sleep

This indicates a brief interruption of sleep continuity.

Question 18

What is included in the PSG report (11)

Answer 18

Total sleep times (TST)
Time in bed
Total time in each stage of sleep
Wake after sleep onset
Sleep efficiency (TST / TIB x 100)
TST % in each stage (time in each stage / TST x 100)
PLMI
Arousal index (arousal per hour of sleep)
Apnoea / hypopnoea index score (AHI)
Hypnogram
Clinical events

It is a key measure in assessing sleep quality.

Question 19

What is the EEG electrode array for sleep monitoring (8)

Answer 19

O1, O2
C3, C4
F3, F4
M1, M2 (mastoids)

Question 20

What is frontal central and occipital electrodes best for?

Answer 20

Frontal- slow waves
Central- spindles
Occipital- alpha

Question 21

What is the recommended standard for scoring Respiratory events

Answer 21

2-5 min epoch

Question 22

What is the recommended standard for scoring periodic leg movements

Answer 22

5 min epoch

Question 23

Why sleep stage? (3)

Answer 23

Gold standard of measuring sleep quality and quantity
Identify stage dependent pathologies
Identify degree and cause of sleep disruption

Question 24

For an 30 second epoch to be classed a sleep stage what is the amount needed?

Answer 24

To score a certain stage of sleep at least half the epoch (15 seconds) must be classified as this stage

Question 25

What is classed as stage 3

Answer 25

Delta / slow waves over more than 20% of epoch,

Question 26

What is classed as REM (3)

Answer 26

.Bursts of rapid eye movements on EOG (does not need to be on every page to continue scoring as REM), .Very low amplitude or absent EMG .Mixed frequency low amplitude EEG- similar to awake

Question 27

What is the normal range for patients without pulmonary pathology on pulse oximetry

Answer 27

95-99 percent

Question 28

What does a score under 95 mean on a pulse oximetry

Answer 28

Could suggest sleep apnoea or severe snoring, seen in COPD or asthma