The relationship between memory and time has been studied extensively but is still poorly understood. A new study assessed memory and time deficits in Alzheimer’s disease (AD) patients in their home environments.
It is widely accepted that as time passes, the ability to recall events and specific information declines. Episodic memory is the type of memory system that allows the storage of information about dated events. Additionally, episodic recall allows for mental time travel, such as the ability to mentally re-experience past events, suggesting an association between memory and time.
Clinical assessments for Alzheimer’s disease (AD) usually open with questions about memory and time. For example, clinicians often ask questions like: “what day of the week is it?” and “what is the date today?” Of course, memory deficits are a hallmark feature of AD, but many studies have also shown deficiencies in timing in individuals with AD, although these tests have been performed in a laboratory setting. To circumvent this issue, a new study published in Brain and Cognition studied memory deficits in AD patients in everyday life.
This study assessed 24 participants with mild AD recruited from retirement homes. Participants were tested on general cognitive functioning, episodic memory, working memory, task switching, , and depression. Notably, researchers asked the participants to recall the years when five remote events ( such as the election of Charles de Gaulle and the president of France in 1958) and five recent public events (such as the inauguration of Pope Francis in 2013). These data were then analyzed to determine whether AD patients have deficits in memory and time, in the context of their home environment.
One key examination in this study was the changes in backward and forward telescoping in AD patients. Backward telescoping refers to the misattributing events to earlier dates, whereas forward telescoping refers to misattributing events to later dates. The findings of this study showed that AD patients had a tendency for backward telescoping for recent events and forward telescoping for remote events. This may be due to a deficit in recalling contextual cues for when the events took place.
The results of this study show a relationship between time and episodic memory. Additionally, AD patients show a decline in memory and the direction of timing biases. Backwards telescoping can be associated with deficiencies in retrieving the context of events; therefore, there is also a link to contextual memory. Deficits in contextual memory have previously been associated with retrograde amnesia and pathological changes in the hippocampus. However, the relation between time and memory is still poorly understood and requires further investigation.
Written by Neeti Vashi, BSc
El Haj M, Janssen SMJ, Antoine P. Memory and time: Backward and forward telescoping in Alzheimer’s disease. Brain and Cognition. 2017 June 16.