Associate Professor Muireann Irish. Photo by Louise M. Cooper.

Research by neuroscientists at the University of Sydney has shown that people living with frontotemporal dementia ­– a form of younger-onset dementia – lose the ability to daydream. The study may lead to greater understanding of behavioural changes associated with dementia, assisting family, carers and researchers in managing the disease.

Most healthy people allow their minds to wander or daydream approximately 50 per cent 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.

The study showed that people living with frontotemporal dementia become increasingly fixed on their external environment and lose the ability to mind wander even during periods of boredom or monotony.

“This study helps us to understand the rigidity and behavioural changes that we typically observe in frontotemporal dementia ,” said Associate Professor Muireann Irish from the Brain and Mind Centre and School of Psychology at the University of Sydney.

“These behaviours can be particularly difficult to manage, as the individual with dementia may appear apathetic and difficult to motivate, particularly in the absence of external stimulation. They become increasingly focused on what is immediately in front of them, such as watching TV, listening to a piece of music, or eating food.”

“Daydreaming is often viewed in a negative light, yet it bestows many important advantages such as flexibility of thought, creativity, and problem solving,” said Associate Professor Irish.

“Individuals with frontotemporal dementia become very rigid in their thinking," she said "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.”

Published in Proceedings of the National Academy of Sciences of the United States of America, the study is 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," said Associate Professor Irish. "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.”

“A population that doesn’t spontaneously daydream is extremely interesting from a theoretical and clinical standpoint. Using neuroimaging analyses, we found that disruption of large-scale brain networks anchored on the hippocampus were associated with this loss of daydreaming,” said Associate Professor Irish.

“Our findings are exciting as they offer new insights into the inflexible and rigid behaviours displayed by these individuals. Moreover, it allows us a unique glimpse of what it would be like to lose a fundamentally human capacity.”