Deep loss of pleasure associated with dementia that starts early

– Loss of pleasure has been revealed as an important feature of early dementia (FTD), as opposed to Alzheimer’s disease.

– Scans have shown that gray matter deteriorates in the so-called pleasure system of the brain.

– These regions were different from those involved in depression or apathy – indicating a possible target for treatment.

People with early dementia are often mistaken for depression and now Australian research has discovered the cause: a profound loss of the ability to experience pleasure – for example, a delicious meal or a beautiful sunset – associated with degeneration of ‘ hedonic focal points’ in the brain where pleasure mechanisms are concentrated.

The research, led by the University of Sydney, revealed clear degeneration or atrophy in frontal and striatal areas of the brain associated with reduced reward, in patients with frontotemporal dementia (FTD).

According to the researchers, this is the first study to show deep anhedonia – the clinical definition for the loss of ability to experience pleasure – in people with FTD.

Anhedonia is also common in people with depression, bipolar disorder and obsessive-compulsive disorder and may be particularly unsuitable for the individual.

In the study, patients with FTD – which usually affects people aged 40-65 years – showed a dramatic decrease from the onset of pre-disease, in contrast to patients with Alzheimer’s disease, who did not have clinically significant anhedonia.

The results suggest the importance of considering anhedonia as a primary feature of FTD, where researchers have found neural drivers in areas different from apathy or depression.

The findings were published today in the leading journal of neuroscience, Brain.

The paper’s senior author, Professor Muireann Irish of the Brain and Mind Center and the School of Psychology at the University of Sydney’s Faculty of Science, said despite increasing evidence of motivational disorders, no study had previously examined the ability to pleasure in humans. with FTD.

“Much of the human experience is motivated by the pursuit of pleasure, but we take this ability for granted.

‘But think of how it is the ability to lose the simple pleasures of life, it has serious consequences for the well-being of people affected by these neurodegenerative disorders.

“Our findings also reflect the functioning of a complex network of regions in the brain, which give an indication of potential treatments,” said Professor Irish, who also recently published an article in Brain on moral reasoning in FTD.

“Future studies will be essential to address the impact of anhedonia on everyday activities, and to inform the development of targeted interventions to improve the quality of life in patients and their families.”

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This is the first study, to the knowledge of the researchers, to show deep anhedonia in FTD, reflecting the loss of gray matter density in the frontal and striatal regions of the brain. Interestingly, anhedonia was not present in a group of participants with Alzheimer’s disease, suggesting that this symptom is specific to FTD.

A total of 172 participants were recruited, including 87 FTD, 34 participants with Alzheimer’s disease. Using brain imaging, researchers found that the loss of pleasure is related to degeneration in a discrete series of regions in the so-called pleasure system of the brain.

The study, led by the University of Sydney, includes researchers affiliated with the ARC Center of Excellence in Cognition and its Disorders, the Royal Prince Alfred Hospital and the Black Dog Institute.

STATEMENT: The authors have no competing interests to declare.