Practice effects and long delays: a case report exploring a novel approach to detecting accelerated long-term forgetting

Objective Accelerated Long-Term Forgetting (ALF) is when newly learned information “decays” faster than expected over an extended period and is associated with temporal-lobe epilepsy (TLE). There is no well-established method for assessing ALF despite its apparent prevalence. We hypothesized that evidencing an absence of practice effects may represent an effective approach to detecting ALF. We sought to determine if this method, along with the long-delay memory tests, could evidence ALF in a single case.

Method We present a 66-year-old male with TLE who had memory complaints despite a stable memory profile over 4 years. Memory tests that employ a short (20–30 min) and a long delay (4 days) condition were used to assess forgetting, whereas repeatedly administered tests were used to detect practice effects. We anticipated poorer memory performance on the long versus short-delay test condition and a lack of improvement on memory tests that were repeated.

Results For repeat administration tests, there was a marked score increase, indicating practice effects, for verbal and visual domains. For long delay tests, however, there was a notable drop with retention falling in the exceptionally low range.

Conclusions These findings suggest a dissociation between long delay and serial assessment tasks for detecting ALF.