Unseen yet overcounted: The paradox of seizure frequency reporting

Objective

Seizure control is often assessed using patient-reported seizure frequencies. Despite its subjectivity, self-reporting remains essential for guiding anti-seizure medication (ASM) decisions and ongoing patient investigations. This study aims to compare patient-reported seizure frequencies with electrographic frequencies captured via ambulatory video EEG (avEEG).

Methods

Data from intake forms and seizure diaries were collected from patients undergoing home-based avEEG in Australia (April 2020–April 2022). Intake forms included monthly seizure frequency estimates. Only avEEG-confirmed epilepsy cases were analyzed. Univariate and multivariate analyses compared seizure frequencies reported via EEG, diaries, and surveys.

Results

Of 3,407 reports, 853 identified epilepsy cases, with 234 studies analyzed after excluding outliers. Diary-reported frequencies correlated with EEG frequency (p < 0.00001), but survey-reported frequencies did not (p > 0.05). Surveys significantly overestimated true seizure frequency (median = 3.98 seizures/month, p < 0.0001), while diaries showed substantially smaller differences (median = 0.01 seizures/month, p < 0.0001). Carer presence was associated with higher diary-reported frequencies (p = 0.047). Age negatively correlated with survey frequency estimation error (p = 0.016). Multivariate analysis identified age and carer status as significant predictors of residuals.

Conclusions

Most patients overestimate their true seizure frequency, potentially influencing therapeutic decisions and raising concerns about the reliability of some participants and carers to self-report seizures in clinical trials.

Significance

An “over-reporting, over-prescribing” cascade may affect epilepsy treatment and highlights the potential issue of clinical drug trials relying on self-reported seizure rates for primary endpoints.