Confabulations Linked to Impaired Mental Time Travel in Alzheimer Disease

A high level of confabulations in Alzheimer disease (AD) is associated with an impaired ability of patients to travel back in time mentally in order to retrieve contextual details linked to the confabulated memory, according to a study published in the Journal of Neuropsychiatry and Clinical Neurosciences.

Researchers sought to evaluate the relationship between confabulations in patients with AD and their ability to mentally go back in time and re-experience or retrieve the context in which confabulated memories were encoded. The study sample included 27 patients diagnosed with moderate stage AD, who were assessed by answering questions about general and personal knowledge, specific personal memories, and personal future plans. Confabulations were evaluated for inconsistent answers of a patient’s past, present, and future (referring to information provided by family and caregivers). The remember/know paradigm was used to assess mental time travel, in which participants were asked to retrieve the context of memories either responding with “remember” or “know.” The latter indicates that the patient has a general feeling of knowing but cannot relive the memory or recall any contextual details.

Results showed significant negative correlation between confabulations and “remember” responses, and significant positive correlation between confabulations and “know” responses. No correlation was discovered between confabulations and episodic memory and central executive function.

Limitations of the study included a small sample size and lack of a control group, which is important in assessing that the confabulations and impaired cognitive function can be attributed to AD and not to normal aging. The study further lacked a structured assessment of behavioral and psychiatric symptoms and concurrent medication use, which are often associated with cognitive functioning.

The findings suggest that confabulations by patients with AD are related to an impaired ability to mentally go back in time to retrieve the context in which the confabulated memories were encoded. A specific cognitive mechanism may be indicated in the occurrence of confabulations and the retrieval of irrelevant memories at the expense of the relevant ones, and should be further studied to offer better clinical strategies to mitigate confabulations in AD.

Reference

Noel M, Larøi F, Gallouj K, Haj ME. Relationships between confabulations and metal time travel in Alzheimer disease [published online May 30, 2018]. J Neuropsychiatry Clin Neurosci. doi: 10.1176/appi.neuropsych.17110266