How epilepsy leads to memory decline

Reduced cell density in certain parts of the hippocampus - a brain region that processes and stores memories - may be linked to deficits in short- and long-term memory in people with epilepsy, particularly those with seizures that affect the temporal lobe, new research has found.

People with temporal epilepsy caused by hippocampal sclerosis (TLE-HS) have impaired memory and find it particularly challenging to recall details of specific events in everyday life.

The researchers evaluated memory and language in 72 patients with TLE-HS who were undergoing pre-operative evaluation, then examined samples of brain tissue that were removed from the hippocampus during epilepsy surgery.

In neuropsychological tests, the researchers found that performance on all elements was worse in patients with degeneration on the right side of the hippocampus compared with the left side.

"Despite the fact that the literature describes only correlation between verbal memory tests and hippocampal cell densities in patients with left hippocampal sclerosis, we found a correlation between right hippocampal cell densities and performance on visual memory tests, including both immediate and delayed recall," said one of the study authors Sandra Mara Comper from Federal University of São Paulo in Brazil.

The findings were presented at the American Epilepsy Society's (AES) 69th annual meeting in Philadelphia.