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The dark night
  1. Charlotte Walker1,
  2. Rhys H Thomas2,
  3. Phil E Smith3
  1. 1Final Year Medical Student, Cardiff University School of Medicine, Cardiff, UK
  2. 2Lecturer in Neurology, University Hospital of Wales, Cardiff, UK
  3. 3Consultant Neurologist, University Hospital of Wales, Cardiff, UK
  1. Correspondence to Dr R H Thomas, University Hospital of Wales, Cardiff CF14 4XW, UK; rhys-thomas{at}

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A 43-year-old woman presented to her general practitioner with increasing daytime tiredness. She had a history of nocturnal events from early childhood and these were occasionally associated with falls and injuries. Although she had no memory of these, she was told that she would wake up and walk around clumsily, sometimes engaging in or initiating limited conversation and performing simple tasks such as switching on the television or opening the front door. On one occasion she was found in the street outside her house in her nightdress; her partner subsequently hid the house key from her each evening.

The episodes lasted approximately 30 min and occurred only once per night, normally within an hour or so of going to bed. They occurred three to seven times a week, exclusively at night and in her own home—never elsewhere. If she drank excessive alcohol during the evening before, the events did not occur. Her neurological and cardiovascular examination was normal, as was her electrocardiogram.

Question 1

What is the differential diagnosis?


Could this be a sleep–wake problem and, if so, which one? There is a wide spectrum of disorders that result in paroxysmal nocturnal events, including sleep related seizures, parasomnias associated with rapid eye movement (REM) and non-REM sleep, sleep related movement disorders and psychiatric disturbances. The diagnosis of parasomnia is notoriously difficult for several reasons, including obtaining an accurate history, superstition surrounding sleepwalking and lack of reliable diagnostic criteria.1

Sleepwalking, or somnambulism, is the commonest of the parasomnias during non-REM sleep. These parasomnias reflect a state of incomplete arousal from deep non-REM sleep (stages 3 and 4), possibly due to an inability to maintain consolidated slow wave sleep. Sleepwalkers commonly display simple or complex motor behaviours, sometimes conducting semipurposeful tasks such as moving objects, dressing, eating and drinking and talking (often nonsensically). …

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  • Patient consent Obtained.

  • Provenance and peer review Not commissioned; not externally peer reviewed.

  • Competing interests None.

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