Subclinical auditory dysfunction in a genetic rat model of childhood absence epilepsy

Childhood absence epilepsy (CAE) is defined by cognitive, behavioral, and neurophysiological abnormalities, but its impact on auditory function remains underexplored. Using Genetic Absence Epilepsy Rats from Strasbourg (GAERS), this study aimed to examine both peripheral and central auditory pathways function to better understand the auditory consequences of CAE.

The experimental and control groups consisted of six-month-old male GAERS (n=6) and Wistar (n=6) rats. Auditory functions were assessed using distortion product otoacoustic emissions (DPOAE) and auditory brainstem responses (ABR). DPOAE amplitudes and ABR wave thresholds, latencies, and amplitudes were analyzed for group comparison.

DPOAE amplitudes were significantly reduced across all tested frequencies in epileptic rats compared to controls. In addition, ABR thresholds were slightly elevated compared to controls, but remained within clinically normal limits. Prolonged latencies were obtained in all waves except Wave I, indicating subcortical auditory pathway involvement in the epileptic group. A distinct ABR amplitude pattern emerged in epilepsy, characterized by increased Wave I-II amplitudes, a marked reduction at Wave III, and subsequent increases at Waves IV-V.

The results showed both peripheral and central auditory nervous system dysfunction in GAERS rats, providing translational insight into CAE. Subclinical abnormalities in auditory neuronal processing may contribute to speech-in-noise difficulties, language impairments, and learning problems in affected children. Early detection and follow-up are valuable for the clinical management of auditory involvement in pediatric epilepsy.