Exploring emotion recognition in people with Parkinson's

Gracey, Maille Frances ORCID: 0000-0003-4366-415X (2026). Exploring emotion recognition in people with Parkinson's. University of Birmingham. Ph.D.

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Abstract

Parkinson’s disease (PD) is a neurodegenerative condition affecting the basal ganglia. Traditionally, PD was viewed as a motor condition, characterised by tremor, rigidity and bradykinesia. PD is now recognised to involve non-motor symptoms, including changes in social cognition. One key domain is facial emotion recognition (FER), which is critical for effective social interaction. This thesis examined FER abilities in people with Parkinson’s (PwP) and controls, and explored physical, pharmacological, and psychological factors that may contribute to differences in FER abilities.

Previous research, has frequently observed reduced recognition of negative emotions in PwP, compared to controls. However, findings can still be mixed, largely due to reliance on static stimuli (e.g. photographs). In Chapter 2, FER abilities were assessed using dynamic point-light face stimuli, providing a more ecologically valid measure. PwP showed reduced emotion recognition accuracy (ERA) scores for happiness and sadness, compared to controls. Furthermore, increasing spatial distance between individual point-lights that made up the outline of the faces displayed, reduced ERA scores (across all emotions tested) in PwP, compared to controls. This suggests that increasing spatial distance of facial features may disrupt emotion processing in PwP.

Chapter 3 explored pharmacological factors by testing the same PwP ON and OFF dopaminergic medication. ERA scores improved when PwP were ON dopaminergic medication, across all emotions tested, indicating that dopaminergic therapy may enhance FER abilities, without altering how spatial and kinematic information is processed.

Chapter 4 assessed psychological factors contributing to differences in FER abilities in PwP. Measures of internal emotional experience did not explain differences in FER abilities. However, higher depression severity in PwP was associated with better FER abilities, whereas lower interoceptive self-regulation in controls was linked to improved FER abilities. These findings suggest distinct psychological influences on FER abilities in each group.

Overall, this thesis demonstrates that PwP show reduced FER abilities compared to controls, likely reflecting a complex interaction between physical, pharmacological, and psychological factors. These findings provide a new insight into how FER abilities may be affected in PwP, and highlight potential areas of interest for future interventions to support social communication and improve quality of life for PwP.

Lay Abstract

Parkinson’s disease (PD) is a condition that affects movement. More recently it has been recognised that it can also impact thinking, emotions, and social interactions in people with Parkinson’s (PwP). For example, the ability to recognise emotions on other people’s faces. This is an important skill for day-to-day communication.

This research explored how well people with Parkinson’s (PwP) recognise emotions from faces, compared to people who do not have Parkinson’s (controls). The research also examined why there may be differences between PwP and controls in their ability to recognise facial emotions.

In the first study, participants watched short videos where faces were displayed as moving dots that outlined different facial expressions. PwP were less accurate at recognising happiness and sadness. When the distance between the dots that outlined the face was increased, PwP were less accurate in identifying the correct emotion, compared to controls.

The next study tested each PwP twice in the PLF task. Once when they had taken their daily medicine for Parkinson’s (ON), and once when they had not yet taken their medicine (OFF). PwP recognised emotions more accurately when ON medication, than when they were OFF medication.

The final study explored how people’s emotions and personal traits might relate to how they recognise emotions in others. In PwP, higher levels of depression were linked to improved accuracy at recognising emotions from faces. In controls, being less aware of body signals, such as breathing, was linked to improved recognition of emotions.

Together, these findings suggest that PwP may have reduced abilities in recognising emotions from faces for a number of reasons. Understanding these differences could help to explain how Parkinson’s can affect communication and guide new ways to support emotional understanding and improve quality of life for PwP.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):