Polysomnography of a 48-year-old woman complaining of unrefreshing sleep reveals repetitive stereotyped extensions of the big toe with flexion of the hip, knee and ankle during NREM sleep, recurring at intervals of 20 to 40 seconds. An index exceeding what value per hour is considered significant in adults?

• A 5 per hour
• B 10 per hour
• C 15 per hour ✓
• D 30 per hour

Explanation

Periodic limb movements of sleep are diagnosed as clinically significant when the index exceeds 15 movements per hour in adults (5 per hour in children). The triad of toe extension with hip, knee and ankle flexion at 20 to 40 second intervals during NREM sleep is characteristic. Unlike restless legs syndrome, these movements are involuntary and occur during sleep.

Reference: Kaplan and Sadock's Synopsis of Psychiatry, 12th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.