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Research paper
‘Cryptogenic Drop Attacks’ revisited: evidence of overlap with functional neurological disorder
  1. Ingrid Hoeritzauer1,
  2. Alan J Carson1,2,3,
  3. Jon Stone1,3
  1. 1Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
  2. 2Department of Rehabilitation Medicine, NHS Lothian, Edinburgh, UK
  3. 3Department of Clinical Neuroscience, Western General Hospital, Edinburgh, UK
  1. Correspondence to Dr Jon Stone, Department of Clinical Neurosciences, Western General Hospital, Edinburgh, EH4 2XU, UK; Jon.Stone{at}ed.ac.uk

Abstract

Objective In their 1973 BMJ paper ‘Cryptogenic Drop Attacks’, Stevens and Matthews described 40, mostly middle-aged, female patients with drop attacks of unknown cause. Although clinically common, there has been little on this topic since. We aimed to determine clinical features, comorbidity and outcome of patients with drop attacks.

Methods We carried out a retrospective review of patients with cryptogenic drop attacks seen consecutively by one clinician (JS) between 2006 and 2016. Demographics, phenomenology, duration and frequency of attacks, attack description and comorbid diagnoses were recorded. Patients were followed up with a notes review.

Results 83 patients with cryptogenic drop attacks were predominantly female (89%, n=79), mean age 44  years. The majority (93%, n=77) could not remember the fall itself and almost half (43%, n=36) experienced prodromal dissociative symptoms. Mechanical trips or syncope preceded drop attacks, historically, in 24% (n=20) of cases. Persistent fatigue (73%, n=61), chronic pain (40%, n=33), functional limb weakness (31%,n=26) and dissociative (non-epileptic) attacks 28% (n=23) were common, with the latter usually preceding or emerging from drop attacks. At follow-up (88%, mean 38 months), 28% (n=23) had resolution of their drop attacks. Predisposing (but non-causative) disease comorbidity was found at baseline (n=12) and follow-up (n=5).

Conclusions Cryptogenic drop attacks are associated with high frequency of comorbid functional somatic and functional neurological disorders. Patients commonly have prodromal dissociative symptoms and in some there was a clear relationship with prior or subsequent dissociative (non-epileptic) attacks. Some cryptogenic drop attacks may be best understood as phenomena on the spectrum of dissociative attacks.

  • drop attacks
  • cryptogenic
  • psychogenic
  • non-epileptic
  • functional neurological symptom disorder

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Footnotes

  • Contributors JS saw the patients, planned and drafted the manuscript. IH collected data and drafted the manuscript. AJC planned and drafted the manuscript.

  • Funding IH is supported by an Association of British Neurologists/Patrick Berthoud Charitable Trust Clinical Research Training Fellowship. JS is supported by an NHS Scotland NRS Career Fellowship.

  • Competing interests None declared.

  • Patient consent Detail has been removed from this case description/these case descriptions to ensure anonymity. The editors and reviewers have seen the detailed information available and are satisfied that the information backs up the case the authors are making.

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

  • Data sharing statement Data on investigations have been updated since an earlier version of this study.

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