Impact of Age on the Diagnostic Yield of Routine
EEG
in People With Childhood or Juvenile Absence Epilepsy: A Cross‐Sectional Study
Francesco Fortunato, Alessia Giugno, Miriam Sturniolo, Enrico Fratto, Pio Zoleo, Francesca Felicia Operto, Ilaria Sammarra, Antonio Gambardella ABSTRACT
Background
We aimed to identify the proportion of individuals with a confirmed diagnosis of childhood absence epilepsy (CAE) or juvenile absence epilepsy (JAE) who show a negative routine EEG (rEEG), and to determine the main factors associated with this finding.
Methods
Individuals with CAE or JAE underwent both an rEEG and a 24‐h ambulatory EEG (24‐h‐aEEG). Participants were classified as ‘rEEG positive’ if generalised spike–wave discharges (GSWs) and/or typical absences (TAs) were observed, and as ‘rEEG negative’ if no such features were detected. 24‐h‐aEEG recordings served as the ground truth to confirm the diagnosis in cases with a negative rEEG.
Results
Eighty‐two individuals [40/82 (48.8%) females; mean age 12.5 ± 5.6 years] were included, of whom 39/82 (47.6%) were not receiving anti‐seizure medications (ASMs) at the time of the EEG. Overall, 31/82 (37.8%) had a negative rEEG, including 10/39 (25.6%) in the cohort of ASM‐naïve individuals. Compared with rEEG‐positive participants, those in the rEEG‐negative group had a later age at epilepsy onset (12.1 ± 4.5 years; p < 0.001) and were older at the time of EEG (16.5 ± 5.3 years; p < 0.0001). Older age at EEG emerged as significantly associated with a negative rEEG (OR = 1.23; 95% CI = 1.03–1.46; p = 0.019), independent of age at onset, epilepsy syndrome (CAE or JAE) and ASM exposure. Sensitivity analyses confirmed the association between older age and rEEG negativity across all cohorts: ASM‐naïve individuals (OR = 1.41; 95% CI = 1.12–1.78), CAE (OR = 1.27; 95% CI = 1.02–1.58), and JAE (OR = 1.36; 95% CI 1.09–1.69) groups. Youden's exploratory analysis identified ≥ 14 years as the optimal threshold for predicting a rEEG negative.
Conclusion
Age significantly reduces the diagnostic yield of rEEG in CAE and JAE, regardless of ASM treatment.