The study, published in Proceedings of the National Academy of Sciences of the United States of America, 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,” Associate Professor Muireann Irish from the Brain and Mind Centre and School of Psychology at the University of Sydney says.
“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.”
It’s understood that most healthy people allow their minds to wander or daydream approximately 50 percent 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 this way 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,” Associate Professor Irish says.
“Individuals with frontotemporal dementia...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.”
The study is the first of its kind to empirically (through experience) measure mind wandering under conditions of low cognitive demand in two types of dementia, and included 35 people with frontotemporal dementia, 24 with Alzheimer’s Disease and 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," Associate Professor says.
"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."
Associate Professor Irish says participants with frontotemporal dementia were completely focussed on the shapes in front of them.
“When asked what they were thinking about, they either reported ‘nothing’ or that they were thinking only about the stimulus itself,” she says.
“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.”
“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.”