Accelerated long-term forgetting in people with newly diagnosed focal epilepsy

Accelerated long-term forgetting (ALF) refers to the phenomenon whereby individuals demonstrate intact recall following a 20-30-minute delay but impaired recall at extended intervals, such as days or weeks. While ALF has been documented in people with chronic or refractory epilepsy, it remains unknown whether this is impacted in those with a new diagnosis of epilepsy. Understanding cognitive impairment in the early stages of epilepsy may have predictive value for patient clinical trajectories and care. The present study employed a multicentre, cohort-controlled design to investigate ALF in people with newly diagnosed epilepsy (NDE) using established memory paradigms. Twenty-two people with NDE and 25 healthy controls completed a battery of cognitive assessments. Memory tests were administered at immediate, 30-minute, and four-week intervals, with initial learning controlled using a 85% criterion. Results showed that people with NDE exhibited accelerated forgetting on a story memory task, despite comparable immediate and 30-minute performance. In contrast, performance on a paired associates task was significantly lower in NDE at all time points, but the rate of forgetting over four weeks was comparable to controls. Visual memory performance showed no group differences or group × time interactions. Recognition trials mirrored these task-specific patterns. These findings indicate that ALF is a cognitive feature in people with NDE and therefore suggests that this impairment is not necessary solely due to the chronicity of epilepsy. Furthermore, the results highlight a potential gap in standard neuropsychological assessment of epilepsy, which may underestimate the extent of memory difficulties patients experience and endorses the need for routine neuropsychological evaluation in the earliest stages of the disorder.