Accuracy of patient-reported spell duration: A comparative study

Abstract

Clinicians rely heavily on patient histories to make medical diagnoses, most of which are inherently subjective and prone to inaccuracies. The aim of this study is to compare the subjective versus objective duration of spells through a retrospective chart review of patients admitted to the epilepsy monitoring unit at our tertiary care medical center. One hundred patients were analyzed. Differences in the accuracy of subjective estimations versus objective duration were compared by age, sex, focal versus generalized, location (frontal versus non-frontal), and spell type (focal aware versus impaired awareness and epileptic versus non-epileptic). Our data show that patients are poor subjective estimators, with 73% of patients overestimating the duration of their spells. We did not find differences in estimated duration by age, sex, seizure location or spell type. A notable exception was patients with generalized convulsive seizures, who accurately reported spell duration to within 17 s. This is likely because these seizures are stereotypical, and patients/family time them. Moreover, patients with non-epileptic spells were worse estimators of their spell duration than those with epileptic spells. In addition, although the prefrontal lobe plays a role in time estimation, we did not find that patients with frontal lobe seizures were worse estimators than those with non-frontal seizures, but invasive monitoring can more precisely localize seizures within areas of the frontal lobe responsible for time estimation. Our data emphasize the importance of not relying solely on patient-reported time estimation in diagnosing and developing treatment plans and instead instructing patients to time their spells.

Keywords: EMU; Epilepsy; Spell duration; Time estimation.