The role of the electroencephalogram as a tool for the investigation of syncope

Abstract

Sir, Syncope, defined as sudden loss of consciousness associated with the inability to maintain postural tone, followed by spontaneous recovery is a common cause for referral to emergency departments. Incidence of a first syncopal episode has been estimated at 6.2 per 1,000 person years or a 10-year cumulative rate of 6 % [1]. Associated risk factors are increasing age and a history of cardiovascular disease. History taking and obtaining a detailed eye-witness account of the event is of paramount importance in correctly assessing people with paroxysmal episodes of loss of consciousness. Electroencephalograms (EEGs) are frequently requested as part of the work up for patients presenting with syncope despite the fact that the potential yield from this is very low [2, 3]. We carried out a retrospective audit over 6 months of all EEG requests for the investigation of syncope. Cases with referral letters containing one or more of the following key terms were included: ‘syncope’, ‘faint’, ‘loss of consciousness’, and ‘micturition associated syncope’. The subsequent EEG results and any comments made upon the simultaneous ECG tracings were recorded. The following data were obtained from the referrals: • Referring team and specialty • Age and sex of the patient • Whether loss of consciousness was documented in the referral • Presence of cardiac symptoms at time of event • Family history of epilepsy • EEG result • Presence of ECG abnormalities, as reported by the attending neurophysiologist