Diagnostic criteria for periodic limb movement disorder

Polysomnography shows repetitive, highly stereotyped limb movements that are:

0.5 to 10 seconds in duration,

Minimum amplitude of 8 mV above resting EMG,

In a sequence of 4 or more movements, and

Separated by an interval of more than 5 seconds (from limb movement onset to limb movement onset) and less than 90 seconds

The PLMS index is ≥5/hour in pediatric cases and ≥15/hour in adult cases

PLMS cause clinical sleep disturbance (difficulty with sleep initiation, sleep maintenance, and/or unrefreshing sleep) or impaired daytime function*

The PLMS are not better explained by another current sleep disorder^¶, medical or neurologic disorder, mental disorder, medication use, or substance use disorder (eg, exclude from PLMS counts the movements at the termination of cyclically occurring apneas)

PLMD: periodic limb movement disorder; EMG: electromyogram; PLMS: periodic limb movements of sleep; RLS: restless legs syndrome.
* If PLMS are present without clinical sleep disturbance or impaired daytime function, the PLMS can be noted as a polysomnographic ﬁnding, but criteria are not met for a diagnosis of PLMD.
¶ A diagnosis of RLS supersedes a diagnosis of PLMD. Thus, a patient can have RLS with PLMS, but not RLS and PLMD.

Modified from:

Allen RP, Picchietti D, Hening WA, et al. Restless legs syndrome: diagnostic criteria, special considerations, and epidemiology. A report from the restless legs syndrome diagnosis and epidemiology workshop at the National Institutes of Health. Sleep Med 2003; 4:101.
Berry RB, Brooks R, Gamaldo CE, et al. The AASM Manual for the Scoring of Sleep and Associated Events: Rules, Terminology and Technical Specifications, Version 2.3, American Academy of Sleep Medicine, Darien, IL 2016. Available at: www.aasmnet.org.

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