Dreaming experience as a useful diagnostic clue for syncopal episodes

The differential diagnosis between epileptic seizures and syncopes is a common occurrence in clinical practice. The manifestations of seizure and syncope sometimes overlap, and available diagnostic testing often not provides a conclusive answer. Syncope is often preceded by a symptom complex characterized by lightheadedness, generalized muscle weakness, giddiness, visual blurring, tinnitus, and gastrointestinal symptoms. These subjective symptoms are very important in guiding the diagnosis. In our experience, the impression of coming out of a dream after the syncopal episode is a subjective symptom commonly reported by patients, if questioned.

To verify the occurrence of dreaming experience after syncope and after generalized tonic-clonic seizures (GTCS) and its diagnostic value in differential diagnosis, we asked 100 patients with GTCS and diagnosis of idiopathic generalized epilepsy (Group 1) and 100 patients with a certain diagnosis of syncope (Group 2) whether they have never felt the impression of coming out of a dream after the loss of consciousness (GTCS or syncope, respectively).

In Group 1, nobody referred the dreaming experience, whereas in the syncope group, 19% of patients referred this subjective symptom.

Dreaming experience seems to be an additional useful diagnostic clue for syncopal episodes, helping the clinician to differentiate them from seizures.