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Frontotemporal dementia grabbed headlines after Bruce Willis’s family announced in 2023 that he had been diagnosed with the disease.
A new study by Swedish researchers at the Karolinska Institute, Lund University, and Umeå University has uncovered the brain processes behind one early symptom: loss of empathy. That finding could help produce more accurate diagnoses and better treatments for the disease.
What Did the Researchers Report?
Symptoms of frontotemporal dementia typically begin to appear in people aged 60 to 70. Primarily, this disease affects behavior, personality, and language abilities, as reported by Medical Xpress.
A hallmark symptom that sets it apart from other dementias, such as Alzheimer’s disease, is an early loss of empathy. Patients may seem less warm toward loved ones and show little concern for their well-being. Those personality changes are deeply distressing for family members, who often feel their attempts to help are met with indifference.
Although researchers have recently studied loss of empathy, the exact brain mechanisms behind frontotemporal dementia remain unclear.
To understand how empathy declines with the onset of dementia, the team studied 28 patients with frontotemporal dementia and compared their data with that of 28 healthy individuals.
They used functional magnetic resonance imaging (fMRI). While participants lay in the scanner, researchers showed pictures of hands being pricked by needles and of hands being gently touched by cotton swabs. The painful images were meant to provoke feelings of distress and suffering. This approach reliably evokes neural responses linked to empathy.
Next, the researchers analyzed the brain activity of dementia patients and healthy individuals as they viewed the images.
In healthy volunteers, the anterior insula, anterior cingulate cortex, and thalamus—regions involved in processing internal bodily signals such as pain—became active when they watched images of a hand in pain.
But patients with frontotemporal dementia showed significantly reduced activity in those regions. The reduction correlated strongly with low empathy scores reported by family members on questionnaires.
Empathy and Brain Function
The study showed reduced activity in brain systems that monitor bodily states and support emotional empathy. That link helps explain why people with frontotemporal dementia may lose the ability to feel for others.
The researchers hope that understanding how the brain processes empathy in frontotemporal dementia will improve diagnosis and pave the way for treatments that could lessen the disease’s impact.
