Somatosensory evoked potentials in patients with typical absences

This study aimed to compare somatosensory evoked potentials (SEPs) in patients with typical absence seizures to healthy controls to elucidate the pathogenesis of absence seizures. We also evaluated potential differences in SEPs based on anti-seizure medication use and seizure type (absence only vs. absence plus generalized tonic-clonic (GTC) seizures).

SEPs were recorded in 20 patients with typical absence epilepsy and 20 age- and gender-matched healthy controls. Latencies and amplitudes of the P25, N20, P25-N35, and N20-P25 components were measured bilaterally and compared between the groups. Subgroup analyses based on medication and seizure type were also performed.

Patients with typical absence epilepsy had significantly higher amplitudes of the bilateral P25-N35 and N20-P25 components compared to controls (p < .05). No significant differences were found in P25 and N20 latencies between the groups. There were no significant differences in SEP parameters based on different medication use or the presence of generalized tonic-clonic seizures in patients.

The increased amplitudes of cortical (N20-P25) and subcortical (P25-N35) SEP components in patients with typical absence epilepsy suggest hyperexcitability of the somatosensory cortex and probably the thalamus. These findings support the involvement of thalamocortical networks in the pathogenesis of absence seizures. The lack of influence of medication on SEP amplitudes indicates these changes may reflect an underlying structural or metabolic abnormality rather than a transient state. Further studies are needed to clarify the mechanisms of absence epileptogenesis.