Download Polysomnogram Interpretation

Interpretation of
Polysomnography

Presented By
Dr. Mohammad Reza Najafi
Professor of Neurology,
Isfahan University of Medical Sciences
Medications

The list of medications is important in the
fact that certain medication can suppress
stage 3 and stage 4 sleep, and some
medications may suppress REM sleep.
Each medication may have a different
affect on the patient’s sleep stages and
fragmentation.
Signs and Symptoms

The signs and symptoms portion is
completed by the patient and helps in
determining the patient’s overall need for
the polysomnogram as well as their chief
complaint.
Recording Protocol

This is the devices and recording
instrumentation used on the patient during
there nocturnal polysomnogram.
Sleep Architecture

The NREM/REM stage and cycle
infrastructure of sleep understood from the
vantage point of the quantitative
relationship of these components to each
other.
Time in bed

Time in bed is the total number of minutes
that a patient spends in bed. This amount
varies for different age groups and can
also vary on an individual patient basis.
This is important because it gives a basic
idea as to whether or not the patient is
spending enough time attempting to sleep.
Total Sleep Time

Total sleep time is the actual amount of sleep
time in a sleep period ; equal to total sleep
period less movement and awake time. Total
sleep time is the total of all REMS and NREMS
in a sleep period. This is important because it
gives a basic idea as to whether or not the
patient is achieving enough sleep for the time
they are in bed.
Sleep Efficiency

Sleep efficiency is the proportion of sleep
in the period potentially filled by sleep, that
is, the ratio of total sleep time to time in
bed. This is important because it displays
the patients overall quality of sleep as it
pertains to any sleep disorder they exhibit.
Sleep Latency

Sleep latency is the period of time measured
from “lights out”, or bedtime, to the
commencement of sleep. This is important
because it can show the level of sleepiness by
how fast the patient gets to sleep or their sleep
latency. It can also help to determine insomnia in
patients that displays signs of excessive daytime
sleepiness but do not achieve sleep in a timely
manner.
Wake Percentage

Wake percentage is the percentage of
wake scored from lights out to the final
wake-up. This is important because it will
help determine how much any sleep
disorder is affecting the patient’s sleep
architecture.
Stage 1

Stage 1 is a stage of NREM sleep that ensues
directly from the awake state. It’s criteria
consists of a low-voltage EEG with slowing to
theta frequencies, alpha activity less than
50%,EEG vertex spikes, and slow rolling eye
movements. Stage 1 percentage is the total time
spent in stage1 sleep from lights out to the final
wake-up. Stage 1 generally constitutes about 25% of sleep.
Stage 2

Stage 2 is a stage of NREM sleep characterized
by the advent of sleep spindles and K
complexes against a relatively low-voltage,
mixed-frequency EEG background, high-voltage
delta waves may compromise up to 20% of
stage 2 epochs. Stage 2 percentage is the total
time spent in stage 2 from lights out to the final
wake-up. Stage 2 generally constitutes 45-55%
of sleep.
Stage 3

Stage 3 is a stage of NREM sleep defined by at
least 20% but not more than 50% of the period
consisting of EEG waves less than 2 Hz and
more than 75 uV, it constitutes deep NREM
sleep. Stage 3 percentage is the total time spent
in stage 3 from lights out to final wake-up. Stage
3 sleep is usually combined with stage 4 sleep
and usually constitutes 12-18% of sleep.
Stage 4

Stage 4 is a NREM sleep that consists of the
same characteristics a s stage 3 over more than
50% of the epoch. Stage 4 percentage is the
total time spent in stage 4 from lights out to final
wake-up.
REM Sleep

REM sleep consists of low-voltage, fast
frequency EEG which may be accompanied by
both saw-tooth waves and rapid eye
movements. REM percentage is the total time
spent in REM sleep from lights out to the final
wake-up. REM sleep usually constitutes 20-25%
of sleep in 4 to 6 episodes.
REM latency

REM latency is the period of time from
sleep onset to the first appearance of REM
sleep. This is important in showing a short
onset of REM sleep, which is a sign of
Narcolepsy.
Respiratory Events

Respiratory events is the breakdown of the
respiratory changes recorded during the
entire polysomnogram.
Obstructive Apneas

Obstructive apneas are respiratory episodes where there
is a complete cessation of airflow lasting greater than 10
seconds and is accompanied by a 4% desaturation or an
arousal.
Hypopneas

Hypopneas are a respiratory episode where
there is partial obstruction of the airway lasting
greater than 10 seconds and accompanied by a
4% desaturation or an arousal.
Central Apneas

Central Apneas are respiratory episodes
where there is no airflow and no effort to
breathe lasting greater than 10 seconds.
Mixed Apneas

Mixed Apneas are respiratory episodes
where there are features of both
obstructive and central apneas in the
same event.
Total events

Total events is the total number of
Obstructive apneas, Hypopneas, Central
apneas, and mixed apneas from lights out
to the final wake-up.
RDI

RDI is an abbreviation for Respiratory
Disturbance Index. This number is the
average number of respiratory events per
hour of sleep. Any RDI lower than 5/hr is
considered to be within normal limits.
REM RDI

REM RDI is the total number of respiratory
episodes per hour of REM sleep.
Supine RDI

Supine RDI is the number of respiratory
episodes per hour of supine sleep. This is
important because the patient may have
only positional apnea and therefore can be
treated with positional therapy.
Oxygen (SaO2)
Baseline = the baseline oxygen level for
the entire polysomnogram.
 Low = the lowest oxygen level recorded
during the polysomnogram.

Miscellaneous

The miscellaneous category is for other
important information regarding the
patient’s polysomnogram.
Blood pressure

Blood pressures are taken both before and after
the polysomnogram. The blood pressure before
the study is to determine a baseline for this
patient. The blood pressure after the
polysomnogram is to help determine any
hypertensive response to sleep apnea or any
other sleep disorder that may be present during
the polysomnogram.
Periodic Limb Movements
# of PLMS = the total number of periodic
limb movements during the
polysomnogram.
 PLMS Index = the average number of
PLMS per hour of sleep.

Arousals
# of arousals = the total number of
arousals recorded during the
polysomnogram.
 Arousal index = the average number of
arousals per hour of sleep.

Technical impression

The technical impression is the overall
breakdown and comments for the entire
polysomnogram.
Diagnosis

The diagnosis portion is where the diagnosis for this
polysomnogram are listed. The diagnosis of Obstructive
sleep apnea is based upon the RDI. A mild RDI would
range from 5/hr. to 15/hr. A moderate RDI would range
from 15/hr. to 30/hr. A severe RDI would be higher than
30/hr. The severity can also be determined by other
factors such as oxygen saturation or position. A person
with a RDI of 28.2 / hr. with accompanying desaturations
below 80% may be considered to have severe OSA.
This is also the portion of the study where any
Hypoxemia, Periodic Limb Movement Syndrome,
Restless Legs Syndrome, Insomnia, Hypertensive
response to apnea, etc.. would be noted.
Recommendations

This is where any recommendations for
treatment would be listed. This can include
positional therapy, nasal CPAP, dental
appliance, and surgery for treatment of
OSAS. This can also include medications
for treatment of Periodic Limb Movement
Syndrome, as well as Insomnia or any
other sleep disorder.