The development of a nonverbal test of accelerated long-term forgetting for use with people with epilepsy

Background: Accelerated long-term forgetting (ALF) is a novel form of memory impairment whereby some people with epilepsy (PWE) demonstrate ‘normal’ patterns of learning and memory over short retention intervals (i.e. 20-30 minutes) but then experience rapid forgetting over longer delays. Currently, there is no consensus on the measures used to assess ALF and little attention has been paid to how clinicians should assess ALF in clinical practice. The aim of this research was to develop and pilot a clinically feasible nonverbal measure of ALF. Method: Phase 1 comprised the initial development and piloting of the Action-People-Places (APP) test materials and procedure. Six versions were created and each version was piloted on small numbers of healthy adults and/or PWE. Modifications to each version were made in line with participants’ performance and feedback. Phase 2 involved administering the final APP test, as well as a brief battery of neuropsychological tests, to 32 healthy adults and an individual, SK, with a confirmed diagnosis of ALF, to assess its reliability and validity. Comparisons were made to two PWE involved in Phase 1. Telephone follow-ups were undertaken at 24 hours, 1-week and 3-weeks. Phase 3 evaluated its acceptability using a brief structured interview format. Results: Healthy adults demonstrated forgetting on the APP test. There were no floor effects but some evidence of ceiling effects. The test had modest levels of reliability (.67-.83). Older age was associated with increased forgetting over time. There were some associations with existing memory measures. SK demonstrated ALF on the task. The APP test was considered acceptable to participants. Discussion: Despite several limitations to the study, including the use of an unmatched healthy adult group, the APP test appears to be a promising measure of ALF, which is worthy of further development with larger patient groups and a more representative control group