Aetiology and prognosis of encephalopathic patterns on electroencephalogram in a general hospital

J Clin Neurosci. 2008 Jun;15(6):637-42. doi: 10.1016/j.jocn.2007.04.004. Epub 2008 Apr 1.


The purpose of this study was to investigate the frequency and clinical outcome of patients with encephalopathic electroencephalograms (EEGs) in a neurophysiology department based in a general hospital. We performed a retrospective review of all EEGs obtained during an 18-month period in a large tertiary referral hospital. The referral reasons for EEG, the diagnoses reached, and patient outcomes were reviewed according to EEG severity. One hundred and twenty-three patients with encephalopathic EEGs were reviewed. The most common referral reason found was for an assessment of a possible first-onset seizure. The most common diagnosis found was one of dementia or learning disability. Of patients who were followed-up for a median of 19 months, 20.7% had died. The mortality rate generally increased according to the severity of the encephalopathy on EEG. However, 21.4% of those patients with excessive theta activity only on EEG had died. This study highlights an increased mortality even in the apparently 'milder' degrees of EEG abnormalities.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Brain Diseases / diagnosis*
  • Brain Diseases / epidemiology
  • Brain Diseases / physiopathology
  • Dementia
  • Electroencephalography*
  • Female
  • Follow-Up Studies
  • Hospitals, General* / statistics & numerical data
  • Humans
  • Learning Disabilities / etiology
  • Male
  • Middle Aged
  • Prognosis
  • Retrospective Studies
  • Seizures / etiology