Dementia patients lose the ability to daydream

A research team led by the University of Sydney has shown that people living with frontotemporal dementia — a form of younger-onset dementia — lose the ability to daydream, in a breakthrough that may lead to greater understanding of behavioural changes associated with dementia.

Most healthy people allow their minds to wander or daydream approximately 50% of their waking lives. These complex thoughts allow people to reflect on the past, anticipate the future and empathise by reflecting on their own behaviour or the behaviour of others. Introspecting in this manner is also associated with acts of creativity, problem-solving and emotional and behavioural regulation.

“Daydreaming is often viewed in a negative light, yet it bestows many important advantages such as flexibility of thought, creativity and problem-solving,” noted Associate Professor Muireann Irish, from the Brain and Mind Centre and School of Psychology at the University of Sydney.

“Individuals with frontotemporal dementia become very rigid in their thinking. They are unable to visualise alternatives, to think of solutions to problems or to deviate from their everyday routines. In previous work, we have shown that their ability to remember the past and to imagine the future is severely compromised. Simply put, these individuals are stuck in the moment.”

Assoc Prof Irish and her colleagues have now revealed the extent to which sufferers of frontotemporal dementia become increasingly fixed on their external environment and lose the ability to mind wander, even during periods of boredom or monotony. Published in the journal Proceedings of the National Academy of Sciences, their study is said to be the first of its kind to empirically measure mind wandering under conditions of low cognitive demand in two types of dementia.

The study included 35 individuals with frontotemporal dementia and 24 individuals with Alzheimer’s disease, as well as 37 healthy older participants. Each participant was asked to view static, two-dimensional, coloured geometric shapes presented individually on a computer screen. Immediately following the presentation of each stimulus, participants were asked to report thoughts that arose while viewing the shapes.

“We found all of the healthy older adults engaged extensively in mind wandering, allowing their thoughts to drift away from the immediate stimulus to more interesting scenarios and ideas,” Assoc Prof Irish said. “What was particularly surprising for us was that individuals with Alzheimer’s disease generated as many instances of mind wandering as healthy older adults, suggesting a relative preservation of at least some forms of internal mentation.

“But the participants with frontotemporal dementia were completely tethered to the stimulus in front of them,” she said. “When asked what they were thinking about, they either reported ‘nothing’ or that they were thinking only about the stimulus itself.

“Using neuroimaging analyses, we found that disruption of large-scale brain networks anchored on the hippocampus were associated with this loss of daydreaming.”

The findings thus offer new insights into the inflexible and rigid behaviours displayed by individuals with frontotemporal dementia, which can be difficult to manage as the individual may appear apathetic and difficult to motivate in the absence of external stimulation. According to Assoc Prof Irish, the study “allows us a unique glimpse of what it would be like to lose a fundamentally human capacity”, assisting family, carers and researchers in managing this devastating disease.

Image credit: ©Warren Goldswain/Dollar Photo Club

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