Scoring Limb Movements

Question 1

What is the polysomnogram criteria for a PLMS

Answer 1

• Duration of 0.5 to 10 seconds
• Greater than or equal to an 8 microvolt amplitude increase
• Time between movements: minimum of 5 seconds the maximum 90 seconds (usual interval 20 to 40 seconds)
• 4 or more movements are needed in a series to be counted (each movement is counted as one PLM)
• Leg movements on two different legs separated by less than 5 seconds from movement are counted as a single leg movement

Question 2

Movements that should not be scored as PLMS

Answer 2

• Isolated, aperiodic movements
• Events around sleep disordered breathing (do not count PLM 1/2 sec before or after a SDB event)
• Transient nonperiodic muscle activity occurring in REM

Question 3

What are the stages of sleep that PLMS are seen?

Answer 3

• Most frequent in N1 & N2
• Less common in N3
• Usually absent REM

Question 4

What is the definition of bruxism?

Answer 4

An increased masseter and temporalis muscle activity during sleep with grinding sounds

Question 5

In what stages of sleep is bruxism usually seen?

Answer 5

N1 & N2 (But can be in any stage)

Question 6

What are the polysomnogram features of bruxism?

Answer 6

• Two types: Brief pattern (0.25 to 2 seconds, at least 3 in a row) or Sustained pattern (greater than two seconds)
• At least one masseter muscle derivation
• In a routine polysomnogram, bruxism is suggested by typical EMG artifact derivations, especially those with M1 or M2
• At least twice the background amplitude
• The episode starts after at least a 3 second interval no muscle activity
• Need minimum of 2 audible episodes per night for a diagnosis

Question 7

What are polysomnogram features needed to diagnose sleep related rhythmic movement disorder

Answer 7

• 0.5 to 2 Hz
• Greater than or equal to four movements in a cluster
• Greater than or equal to 2x background EMG amplitude
• TimeSync video polysomnogram

Question 8

What are the polysomnogram features for REM behavior disorder

Answer 8

• Sustained muscle activity (Tonic activity)
• 50% of the epoch has EMG amplitude that is greater than the minimum amplitude in non-REM and/or Excessive transient muscle activity (Phasic activity)
• A 30 second epoch is divided into 10 sequential three second mini epochs
  
  • 0.1 to 5 second duration
  • At least four times the amplitude of the background EMG
  • At least 50% of the mini epochs contain bursts of transient muscle activity

Question 9

Major Body Movement: Scoring sleep stage if the movement and muscle artifact obscures more than 1/2 the epoch to the extent that stage cannot be determined

Answer 9

• Score as W, N1, N2, N3 or REM
• If alpha rhythm is seen in any part of the epoch then score as W
• If the epoch before or after is W, score the epoch with MBM as W
• Otherwise score the epoch the same stage as the epoch after the MBM