New research reveals how behavioral variant frontotemporal dementia (bvFTD) alters empathy processing, with advanced imaging revealing profound disruptions in the brain areas responsible for understanding and responding to the pain of others.
Study: Altered empathy processing in frontotemporal dementia. Image credits: Chinnapong / Shutterstock.com
A recent study published in JAMA network opened uses advanced imaging technologies to measure changes in empathy for pain in patients with behavioral variant frontotemporal dementia (bvFTD).
The neurology of empathy
Empathy refers to an individual’s ability to perceive, be sensitive to, and care about the emotional well-being of others. Several areas of the brain are involved in empathy, including mirror neurons, the anterior insular and medial prefrontal cortex, the amygdala, the basal ganglia, the anterior cingulate cortex, and the orbitofrontal cortex.
Loss of empathy is a hallmark feature of bvFTD, which can result in affected individuals being inconsiderate of others and unable to respond to the concerns of loved ones. In severe cases, bvFTD can lead to questionable moral behavior that can negatively impact their ability to form and maintain relationships.
Previous research suggests that the lack of empathy in bvFTD stems from the impaired functioning of frontoinsular and temporal neuronal structures that are essential for processing social information. Furthermore, bvFTD has been shown to directly impact the ventromedial prefrontal cortex, which is primarily responsible for regulating complex emotions, controlling impulsive behavior, and making moral judgments.
About the study
In the current study, 28 patients with bvFTD were compared with an equal number of controls with normal cognitive function in a classical case-control study. Patients and controls were similar in their median ages of 66.7 and 67.6 years, respectively, as well as their distribution of education level.
The current study was conducted at three centers in Stockholm, Sweden. The Interpersonal Reactivity Index (IRI) was used to assess empathy by measuring its cognitive and affective aspects.
Task-based functional magnetic resonance imaging (fMRI) was used to monitor any changes in brain activity in controls and cases.
Subtraction techniques were used to eliminate the blood oxygen level dependent (BOLD) signal at baseline from the signal in the pain condition. This allowed the researchers to isolate the brain responses associated with empathy for pain (EFP).
Two regions of interest (ROIs) were selected: one based on a meta-analysis of areas commonly reported to be activated during EFP and the other based on the activation pattern observed in controls during EFP (CA-ROI). CA-ROI was used to investigate associations with empathy-related responses, as this region showed normal activation patterns in this task.
Reduced empathy signal in bvFTD
The BOLD signal during EFP was increased in only two areas in bvFTD patients compared to 12 areas in controls. The BOLD signal was reduced below the ROI related to affective empathy, with the average change during EFP being approximately 21% for controls, compared to -1.3% for cases. However, no reduction in BOLD signal was observed under the cognitive empathy ROI.
The EPF-BOLD signal in the CA-ROI was increased in control participants who reported higher self-perception of empathic feelings in the IRI. In bvFTD patients, the signal for EPF was positively correlated with informants’ assessment of the patient’s empathic concerns. So, according to others, the higher this signal, the more likely the patient would have empathic feelings.
Conclusions
The fMRI findings in the current task-based study of empathy for pain in fvFTD cases showed reduced responses in brain areas essential for processing empathic feelings. This change reflects an early impact of the various changes in neuronal structure and function that occur in bvFTD.
The magnitude of empathy-related neural activity was correlated with the patient’s ability to experience empathy, as assessed by the individuals living with the patients affected by bvFTD.”
The current study used multiple fMRI devices, which may have introduced variability in the outcomes. An additional limitation of the current study concerned the inclusion of patients with both sporadic and genetic bvFTD. Furthermore, bvFTD diagnoses were clinical, without neuropathological confirmation.
Journal references:
- Mendez, M.F., Akhlaghipour, G., Jiminez, E.E. (2021). Empathy and impaired social-emotional self-perception in frontotemporal dementia. The Journal of Neuropsychiatry and Clinical Neuroscience 34(2). doi:10.1176/appi.neuropsych.21040099.
- Lindbergh, O., Li, T., Vestberg, S., et al. (2024). Altered empathy processing in frontotemporal dementia. JAMA network opened. doi:10.1001/jamanetworkopen.2024.48601.