Frontotemporal dementia has gained significant attention in recent years after the family of actor Bruce Willis announced in 2023 that he had been diagnosed with the condition . A year later, it was revealed that US chat show host Wendy Williams had also been diagnosed with the condition .
Authors
- Alexander F Santillo
Associate Professor of Psychiatry, Consultant Psychiatrist, Lund University
- Olof Lindberg
Associate Professor, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet
Yet despite all this recent attention, there's still much we don't know about frontotemporal dementia - including what mechanisms cause certain symptoms, and how we can better spot signs of the disease earlier on. But our research has uncovered the brain processes that underlie one of the disease's earliest symptoms. This finding brings us one step closer to better diagnosing and treating the condition.
Frontotemporal dementia accounts for approximately 5% of dementia cases . Symptoms typically begin in a person's late sixties or seventies. The disease primarily affects behaviour, personality and language abilities.
A hallmark symptom of frontotemporal dementia, which sets it apart from other forms of dementia (such as Alzheimer's disease), is early loss of empathy. This often manifests as diminished warmth and concern for loved ones. This symptom can be profoundly unsettling for family members and loved ones close with the patient. They may feel as though the patient's personality has transformed - and that their efforts to help and support are met with indifference.
While loss of empathy has been the focus of much research from the scientific community, the precise brain mechanisms underlying the loss of empathy in frontotemporal dementia remain unclear.
Alongside colleagues from Karolinska Institute, Lund University and Umeå University in Sweden, we conducted a study which sought to understand how empathy diminishes in frontotemporal dementia. We looked at 28 patients with frontotemporal dementia and compared them against 28 healthy people.
To conduct our study, we used a type of brain scan called functional magnetic resonance imaging (fMRI). While in the fMRI scanner, participants viewed images of hands being pricked by needles. These images were contrasted with those of hand being touched by a q-tip. This is a well-established neuroscience test that is designed to evoke feelings of concern and distress as witnessing another person in pain. We analysed the brain activity of the patients with frontotemporal dementia as they viewed the images.
In healthy volunteers, the anterior insula, anteria cingulate and thalamus are the brain regions responsible for monitoring internal bodily signals (such as pain). These brain systems became active when they observed the images of a person in pain.
But in the patients with frontotemporal dementia, activity in these crucial brain regions was significantly reduced. These reductions were strikingly related to the degree of empathy patients exhibited in their daily lives, as judged by questionnaires filled out by family members.
Empathy and brain function
Empathy is typically thought to be comprised of two dimensions. Emotional empathy is the ability to react to others' feelings (such as their distress and concern). Cognitive empathy is the capacity to understand the intention of others.
Although the two are closely related, they're not quite the same thing. It's also possible for a person to possess one facet of empathy but not the other. The difference between the two facets of empathy can actually be exemplified by two psychiatric conditions, antisocial personality disorder and autism.
People diagnosed with antisocial personality disorder are typically good at understanding the intentions and motivations of other people ( cognitive empathy ), but cannot empathise emotionally. This can lead to a disregard for other people. On the other hand, a person with autism typically has emotional empathy skills but might not have the ability to infer other peoples' intentions ( cognitive empathy ).
Our study revealed reduced activity in parts of the brain associated with the brain's monitoring of bodily states, which are typically used when emotionally empathising with another person. These findings underscore the critical link between this brain system and our capacity to take others into consideration.
In light of these findings, the next step with our research is to explore if and how the in-flow of the bodily signals necessary for the brain to create an inner self is altered in frontotemporal dementia - and how this relates to empathy.
Apart from about 30% of cases being genetic , the causes of frontotemporal dementia remains unclear. Despite intense efforts from the community, there's currently no cure. But thanks to courageous sufferers and their families coming forward, awareness is increasing. This is a crucial thrust forward.
We hope that understanding how the brain processes empathy in frontotemporal dementia may not only help improve diagnosis but may, in the future, pave the way for potential treatments which mitigate some of the devastating effects of this disease.
Alexander F Santillo is primarily funded by the Swedish federal government, The Åke Wiberg Foundation, The Schörling Foundation and The Bundy Academy.
Olof Lindberg receives funding from the Schörling foundation and the Olle Engkvists Foundation.
