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• To sleep or not to sleep
  Mark RA Manford
  Published on: 12 July 2004

• Published on: 12 July 2004

  To sleep or not to sleep

  • Mark RA Manford, Neurologist

  Dear Editor

  The authors [1]. usefully describe a large series of patients and compare the occurrence of non-epileptic seizures arising whilst apparently asleep.

  This clinical differentiation remains problematic and the rule appears to be emerging that there are no rules. However, to my knowledge there is only one study [2]. (quoted by Duncan et al) with video-EEG-recording, maintaining that patients can...

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  Dear Editor

  The authors [1]. usefully describe a large series of patients and compare the occurrence of non-epileptic seizures arising whilst apparently asleep.

  This clinical differentiation remains problematic and the rule appears to be emerging that there are no rules. However, to my knowledge there is only one study [2]. (quoted by Duncan et al) with video-EEG-recording, maintaining that patients can have a non-epileptic seizure, without prior arousal, documented on EEG. If true, this would revolutionise views on non-epileptic attacks and clearly it needs verification.

  In every other documented case, the patient wakes up before the attack and to say they are in “pseudosleep” is obfuscation by jargon – they are awake. Arousal from sleep before the attack is often brief; anyone who has woken in a sweat the night after a tricky exam knows this.

  The problem as always in epilepsy diagnosis, is that until the attack is recorded in the telemetry laboratory, the evidence on which the diagnosis is based is from the history, which is simply wrong. It is widely held that epilepsy is a clinical diagnosis; this too is wrong.

  Epilepsy is due to pathological electrical discharges, but unfortunately usually we can’t record them because they are too infrequent. Consequently, we diagnose epilepsy by a clinical educated guess, but a guess is not a diagnosis, it is just the best we can manage and it usually works OK. This needs to be remembered in all studies looking at seizure histories.

  The authors also state that they include patients with any episodes apparently arising in sleep in their study, no matter how infrequent. The numbers here are important. The patient who has a sudden onset of refractory seizures as a young adult with the occasional one in the night probably has non-epileptic seizures and is very different from the one who has 80% of their attacks at night and wakes with a bitten tongue. I would be interested to know these data.

  Finally, the authors hold up my article for the educational supplement for JNNP [3]. as an example of a modern paper with an out-dated view that misleads clinicians. In fact this article states: “attacks arising from sleep are organic (though not always epileptic) though it may take an EEG to prove that the patient is asleep at the onset”.

  In my view, with the proviso of Orbach’s study, this remains entirely accurate and Duncan et al’s final sentence merely paraphrases it. To have been misrepresented in this way is highly regrettable and I take this opportunity to set the record straight.

  References

  (1). Duncan R, Oto M, Russell, AJC, Conway P. Pseudosleep events in patients with psychogenic non-epileptic seizures: prevalence and associations. JNNP 2004;75:1009-1012.

  (2). Orbach D, Ritaccio A, Devinsky O. Psychogenic non-epileptic seizures associated with EEG-verified sleep. Epilepsia 2003;44:64-68.

  (3). Manford M. Assessment and investigation of possible epileptic seizures. JNNP 2001;70(suppl.2)3-8

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  Conflict of Interest:
  None declared.

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