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Intermediate Technical IVT

PLMS

Also written as: PLMS — Periodic Limb Movements of Sleep

Repetitive, involuntary leg movements during sleep characterized by dorsiflexion of the foot and extension of the big toe, occurring in sequences.

Full Definition

PLMS (Periodic Limb Movements of Sleep) are repetitive, involuntary movements of the legs that occur during sleep, characterized by dorsiflexion of the foot at the ankle, extension of the big toe, and sometimes flexion at the knee and hip. To be classified as PLMS, movements must occur in sequences of four or more, each lasting 0.5-10 seconds, with intervals of 5-90 seconds between movements. PLMS are quantified using the Periodic Limb Movement Index (number of movements per hour of sleep). While PLMS can be found in healthy individuals, they're often associated with restless legs syndrome, sleep disruption, and various medical conditions. Clinical editors should note that PLMS require polysomnographic documentation for diagnosis.

Usage

Usage note: Always specify the PLMS index and association with arousals when present.

In Context

  • "The sleep study revealed a PLMS index of 25 per hour, indicating moderate periodic limb movements." — Polysomnography report
  • "PLMS were associated with frequent microarousals throughout the night." — Sleep disorder assessment

Also known as

periodic leg movements PLM

Contrasted with

normal sleep movements

Don't confuse with

restless legs syndrome hypnic jerks REM behavior disorder

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