Relationship Between Cognitive Impairments and Serum Orexin Levels in Epilepsy Patients

Objective: Recent studies on neurodegenerative diseases have indicated that Orexin A plays a role in cognitive impairment.Furthermore, animal studies have demonstrated that Orexin A enhances synaptic plasticity in the hippocampus.The present study aimed to investigate the potential effect of orexin A on cognitive decline in patients with epilepsy.Methods: This study included patients with epilepsy (patient group), including those with idiopathic generalized epilepsy (IGE subgroup) (n=24) and mesial temporal lobe epilepsy (mTLE subgroup) (n=17), and healthy controls (control group) (n=27), all aged 18-65 years.The Wechsler Memory Scale (WMS) visual memory subtest and Oktem Verbal Memory Processes Test (OVMPT) (15-word Turkish verbal learning memory test) were administered to all participants.Serum Orexin A levels were measured using enzyme-linked immunosorbent assay. Results:The mean Orexin A level in the control group was 25.8414.65pg mL -1 , versus 24.5712.50pg mL -1 in the IGE group and 23.0112.86pg mL -1 in the mTLE group.There were no significant differences in the Orexin A level between any of the groups/subgroups.Moreover, no significant correlation was observed between the Orexin A level, WMS visual memory subtest, and OVMPT scores.Conclusion: Our findings showed no association between the Orexin A level and cognitive impairment in patients with epilepsy.Further studies are needed to clarify the complex role of Orexin A in cognitive function.