Huntington’s disease patients’ inability to recognize people’s emotions from their facial expressions appears to be linked to dysfunction in more than one area of the brain, according to a study.
The brain areas include “emotion–related regions, such as front-striatal networks and limbic areas, and regions associated with visual processing,” according to the study, “Beyond Emotion Recognition Deficits: A Theory Guided Analysis Of Emotion Processing In Huntington’s Disease.” The authors based their work, published in the journal Neuroscience & Biobehavioral Reviews, on a review of previous findings.
Huntington’s patients have difficulty interpreting emotion-related stimuli — not just facial expressions, but scenes, descriptions of situations, and smells and tastes. Several studies have shown they are particularly ill-adept at recognizing facial emotion.
Progress in understanding the emotional side of neurodegenerative diseases such as Huntington’s has been limited, the authors said. A key reason is that there have been few attempts to connect clinical information on the diseases with theories of emotion-processing developed in the fields of psychology and affective neuroscience.
To try to obtain a broader understanding of Huntington’s patients’ inability to recognize facial emotion, the researchers reviewed several studies dealing with the issue.
“Our analysis of the literature confirmed that the ability to recognize basic emotions from other people’s facial and non-facial expressions has consistently been found to be impaired in symptomatic and pre-symptomatic (Huntington’s patients), with the most pronounced deficits occurring for negative emotions,” the authors wrote.
They also found studies indicating that some Huntington’s patients can process emotion-related stimuli, including in interactions with others.
One reason many patients are unable to recognize emotion from facial expressions may be that they are unable to process the faces themselves, the authors suggested.
Another possibility, the team said, is that Huntington’s patients have difficulty relating to others’ experiences, perhaps due to reduced motor-system response.
In fact, previous studies have suggested a link between difficulty reading facial expressions and impaired motor skills, the authors said.
“Our review revealed several gaps in knowledge related to emotion processing in (Huntington’s disease),” they wrote. “(More) research is needed for a complete characterization of emotion processing in (this disease), and might also contribute to a better understanding of well-researched emotion processing deficits.”