Severe loss of pleasure related to early-onset dementia

Loss of pleasure, unlike Alzheimer’s disease, is an important feature of early dementia (FTD).

– Scans showed gray matter deterioration in the brain’s so-called pleasure system.

– These regions were different from the regions involved in depression or apathy – suggesting a possible treatment goal.

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

The University of Sydney-led study revealed marked degeneration or atrophy in frontal and striatal areas of the brain associated with reduced reward in patients with frontotemporal dementia (FTD).

The researchers believe this is the first study to demonstrate profound anhedonia – the clinical definition for the loss of the ability to experience pleasure – in people with FTD.

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

In the study, patients with FTD – which generally affects people ages 40-65 – showed dramatic decline from the onset of the disease, in contrast to patients with Alzheimer’s, who did not appear to have clinically significant anhedonia.

The results point to the importance of considering anhedonia as a primary presenting feature of FTD, where researchers found neural drives in areas different from apathy or depression.

The findings are published today in the leading neuroscience journal, Brain

The paper’s senior author, Professor Muireann Irish of the University of Sydney’s Brain and Mind Center and the School of Psychology in the Faculty of Science, said that despite growing evidence of motivational disorders, no studies had previously explored the ability to enjoy pleasure. to be experienced in people with FTD.

“Many human experiences are motivated by the urge to have fun, but we often take this ability for granted.

“But just think what it might be like to lose the ability to enjoy the simple pleasures of life – this has major implications for the well-being of people affected by these neurodegenerative disorders.

“Our findings also reflect the workings of a complex network of brain regions, which signal potential treatments,” said Professor Irish, who also recently published a paper in Brain about moral reasoning in FTD.

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

To the researchers’ knowledge, this is the first study to demonstrate profound 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 was linked to degeneration in a distinct set of regions in the brain’s so-called pleasure system.

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 conflict of interest to declare.