Abstracts

Rationale: Many individuals with focal epilepsy experience delays to diagnosis that result in preventable morbidity and mortality. In this study, we investigated whether delays to diagnosis differed between childhood- and adult-onset epilepsy. Furthermore, we evaluated the characteristics predictive of diagnostic delays in childhood-onset seizures as well as morbidity associated with these delays.

Methods: This was a retrospective analysis of the enrollment data from the Human Epilepsy Project, an international multi-institutional study that collected data from 34 sites in the USA, Canada, Europe and Australia between 2012-2017. Participants enrolled were 12 years or older within 4 months of diagnosis of focal epilepsy. At enrollment, subjects were asked to identify the duration of seizures prior to diagnosis. A total of 444 participants were analyzed, 121 participants reported onset of focal seizures at age ≤18 years, and 323 participants reported adult-onset seizures.

Results: Demographic and clinical characteristics were similar between groups. Median time to diagnosis from first seizure was longer in the childhood-onset group compared to the adult-onset group, with a median of 340 vs 207 days (p=0.012). Non-motor seizures were associated with a longer delay to diagnosis in both groups and was approximately twice as long in the non-motor childhood-onset group vs. the non-motor adult-onset group (1,014 vs 519 days; p=0.02). Furthermore, when stratified by different age groups, participants with childhood-onset non-motor seizures before 12 years suffered longer delays to diagnosis than those 12-24 (p=0.004), who in turn suffered longer delays to diagnosis than those >24 years of age (p=0.03). Conserved awareness was associated with longer delays to diagnosis (p < 0.001). When evaluating morbidity, the childhood-onset group experienced more seizures prior to diagnosis than the adult-onset group (p < 0.001). A significant difference was also seen in number of total injuries in non-motor childhood-onset participants who later developed motor symptoms vs those who never developed motor symptoms (54.9% vs 4.3%; p < 0.001). Importantly, those who converted from non-motor to motor type seizures experienced the greatest delays in diagnosis when compared to both non-motor and motor only groups (median 1615 days vs 221 days vs 61 days; p < 0.0001; p = 0.0001).

Conclusions: This study highlights the disproportionate delay to diagnosis experienced by individuals with focal non-motor seizures as compared to focal motor seizures and shows that this disparity extends to childhood-onset individuals. Furthermore, this study points to a new finding of longer delay experienced by those with childhood-onset epilepsy as compared to adult-onset. Moreover, those with onset of epilepsy at younger ages may experience the longest delays to diagnosis. These delays are associated with not only more seizures, but also conversion to motor-type seizures and potentially preventable injuries.

Funding: Please list any funding that was received in support of this abstract.: N/A.