You are currently viewing Non-24-h Sleep-Wake Rhythm Disorder Mnemonic

Here is a quick mnemonic “NIGHT HOURS NIGHTS to remember about Non-24-h Sleep-Wake Rhythm Disorder

This can be valuable for patients as well as medical doctors, nurses & students doing their clinical rounds. You can also find it very useful for med exams like USMLE, MBBS, NEET PG, FMGE, NExT, MCAT & NCLEX exams

Non-24-h Sleep-Wake Rhythm Disorder : How To Remember Easily ?

  • N – Non-24-h sleep-wake rhythm disorder
  • I – Input from the environment lost in N24SWD
  • G – Geophysical day vs. circadian pacemaker difference
  • H – Hours of nighttime sleep for most blind patients
  • T – Trouble maintaining stable phase relationship
  • H – Insomnia bouts in blind patients with N24SWD
  • O – Out-of-phase circadian rhythms cause sleepiness
  • U – Uniting endogenous rhythms with the local environment
  • R – Remission of symptoms when in phase with the environment
  • S – Symptomatic phases can last weeks to months
  • N – Non-entrained circadian pacemaker synchronization
  • I – Improving sleep with low-dose melatonin administration
  • G – Genetic mutation causing N24SWD in some cases
  • H – Incremental pattern of sleep timing delays in sighted patients
  • T – Time phase shifting in and out of sync with local time
  • S – Seldom seen clinical presentation in blind patients with N24SWD


Dr. Arin Nandi

Passionate About Medical Science & Helping Future Doctors Achieve Top Ranks In Medical Exams. He is professionally a dentist as well as a public health expert from JIPMER working in department