Memory and time: Backward and forward telescoping in Alzheimer's disease

- Backward telescoping refers to misattributing events to previous dates.
- Forward telescoping refers to misattributing events to later dates.
- AD participants showed backward telescoping for recent public events.
- They also showed forward telescoping for remote public events.
- Backward telescoping is related to context memory and hippocampal decline in AD.

Backward and forward telescoping are opposite timing biases. The former refers to misattributing events to earlier dates, whereas the latter refers to misattributing events to later dates. The present study investigated both biases in participants with Alzheimer's Disease (AD) and healthy older adults, matched on age, sex, and education level. Participants were asked to recall the years when five remote and five recent public events had occurred. They were also assessed with a cognitive and clinical battery that included a context memory task on which they had to associate letters and locations. Results showed backward telescoping for recent events and forward telescoping for remote events in AD participants and older adults. Furthermore, poorer context recall was observed in AD participants and older adults displaying backward telescoping than in those displaying forward telescoping. These findings suggest an association between the amount of contextual information recalled and the direction of the timing bias. Backward telescoping can be associated with deficiencies in retrieving context characteristics of events, which have been associated with retrograde amnesia and pathological changes to the hippocampus in AD.