New Insights About Accelerated Long-Term Forgetting in Epilepsy

Accelerated Long-Term Forgetting: Overlooked in Epilepsy?

ALF is memory loss that occurs after days or weeks in a patient with normal short-term memory

Incidence rates and underlying causes of ALF in epilepsy are unknown

Standard memory testing usually evaluates shorter term memory deficits, and may not detect ALF

Research suggests that some patients with epilepsy may experience ALF, especially those with temporal lobe abnormalities

New insights on ALF in Focal Epilepsy[1]

Conducted at the University of Sydney

Included 44 patients with focal seizures

Used two standardized, 15-item lists to test memory at 30 minutes and 7 days:

Rey Auditory Verbal Learning Test (RAVLT): tests word recall

Aggie Figures Test: tests recall of abstract line drawings

ALF: normal short-term results, impaired 7-day results

Compared results to a control group of 60 patients without neurological or psychological history

ALF Increased in Focal Epilepsy

Nearly twice as many patients with focal seizures showed ALF vs controls (23% vs 12%)

33% of patients with ALF had temporal lobe epilepsy

Hippocampal lesions were the main predicting factor

   -ALF found in 41% of patients with hippocampal lesions vs only 11% without (p<.05)

Test Type Influences Detection of ALF

Rates of ALF differed based on test type:

  -RAVLT: 18% of patients with focal epilepsy had ALF

  -Aggie Figure Test: 7% of patients with focal epilepsy had ALF

Standard Testing May Miss ALF in Focal Epilepsy

Patients with focal seizures may show memory deficits at longer delays than standard evaluation can pick up

Adding long term recall questions to standard memory assessments may detect ALF

ALF may be most common in temporal lobe epilepsy with hippocampal lesions

Take Home Points

.Small, single center study adds to evidence that ALF may be an important memory disorder in epilepsy

.ALF prevalence may be higher in patients with temporal lobe epilepsy with hippocampal lesions

.Standard testing may miss ALF

.Incidence of ALF may vary based on type of test; testing word recall after one week may be particularly helpful in detecting ALF in focal epilepsy