Periodic Limb Movements of Sleep

DEFINITION
PLMS are common in healthy adults and is associated with RLS (80%) and other sleep disorders like OSA, Parkinson’s and narcolepsy. PLMS is defined as periodic episodes of repetitive and stereotyped limb movements occuring during sleep.

Many people suggest that RLS is a sensory component and PLMS is a motor component.
The are typically repetitive 0.5-10 secs long and separated by 20-40 secs range.
More pronounced in N1 and N2 stage of sleep, often accompanied by K complexes on PSG. They may result in arousals

CRITERIA BY AASM
Minimum number of consecutive limb movement events needed to define a PLMS is 4 LMs
Minimum period length between LM to include as PLMS is 5 secs
Maximum period length between LMs is 90 decs
LMs on 2 different legs separated by <5 secs are counted as single movement Amplitude > 8 uV above baseline

SYMPTOMS
Difficulty falling asleep / staying asleep
May sometimes happen in the arms as well
Burning, tingling sensations or general discomfort – when they lay down to rest
Happens in batches from 30 mins to 2 hours
Daytime fatigue, feeling unrested and fatigue

CAUSES
Anemia / Ferritin deficiency
CNS problems
Kidney disorder
Hereditary

TREATMENT
Iron supplements
Extreme cases – pain medications / Dopamine agonists
Healthier diet, balanced exercise