Late-onset epilepsy implicated in impaired cognitive function in midlife
Individuals with late-onset epilepsy (LOE) appear to exhibit faster declines in global cognition, verbal memory, executive function, and word fluency over time compared with those who do not have the neurological disorder, and some of these declines occur prior to the index seizure, a study has found.
Researchers used data from the Atherosclerosis Risk in Communities (ARIC) study and analysed cognitive scores from ages 45–64 to 72–94 among ARIC participants to characterize longitudinal cognitive changes in relation to LOE (defined as ≥2 seizure events starting at age ≥67 years). The participants underwent evaluations prior to seizure occurrence.
The analysis included 8,033 participants (57 percent female; 20.4 percent black), among whom 585 developed LOE. The corresponding incidence rate was 3.62 per 1,000 person-years.
Over 25 years of follow-up, participants who did vs did not develop LOE showed a steeper global cognitive decline (−0.43 vs −0.017 z-score points). This difference was comparable to an age-associated difference of 6.5 years, that is between a 55-year-old and a 61.5-year-old person at baseline.
Notably, within the 14-year period prior to the onset of seizures, participants in the LOE group had already exhibited rapid cognitive declines on measures of Delayed Word Recall Test (DWRT), Digit Symbol Substitution Test (DSST), and global z‐scores than did those in the non-LOE group.
After the first seizure, DSST and WFT performance in participants with LOE declined more steeply than it did prior to seizure onset.Based on the present data, the researchers underscored the importance of establishing the causes of cognitive decline in individuals with LOE to identify risk factors that can be improved. Clinicians should be aware of the potential for cognitive impairment, as those with LOE may develop difficulty with medication management and other daily tasks.