Gait and emotions in Parkinson’s disease: from behavioral to neurophysiological mechanisms

Gait disturbances are a hallmark of Parkinson’s disease (PD), traditionally considered a motor deficit but increasingly recognized as a complex behavior integrating sensorimotor and affective processes. Within the framework of embodied emotion theories, gait not only supports locomotion but also conveys and is influenced by emotional states through reciprocal bottom-up and top-down mechanisms. This thesis aimed to investigate the bidirectional relationship between emotion and gait in PD, combining behavioral, perceptual, and neurophysiological approaches. First, we examined how environmental context and task complexity influence emotional responses during gait observation. PD patients and healthy subjects (HS) evaluated arousal and valence elicited by videos of walking under varying demands and contexts. Arousal increased with task complexity and was higher in natural versus built environments, with PD patients showing overall heightened arousal compared to HS, suggesting increased emotional reactivity to gait-related challenges. To enable systematic investigation of emotional embodiment, we developed and validated a set of standardized emotional gait stimuli. Healthy participants reliably recognized most emotions conveyed through gait, even when facial expressions were obscured, confirming that body movement alone provides sufficient emotional information and establishing a robust tool for studying emotion recognition and simulation. Using these stimuli, we then explored emotional recognition in PD. Patients largely preserved the ability to identify emotions and their valence from gait, although they exhibited reduced intensity ratings, indicating a selective impairment in emotional appraisal rather than recognition. This emotional blunting may contribute to altered interaction with movement-related cues. Finally, we investigated whether emotional gait observation modulates motor performance and neural activity. Both PD patients and HS showed emotion-dependent changes in gait: positive emotions (happiness) improved spatiotemporal parameters, whereas negative emotions (sadness, anxiety) impaired performance. Functional MRI revealed corresponding modulation of sensorimotor and basal ganglia networks, with emotion-specific activation patterns linked to changes in gait kinematics, particularly in PD. Overall, these findings demonstrate that emotion and gait are deeply interconnected in both health and Parkinson’s disease. Emotional processing influences motor control, and gait observation engages affective and sensorimotor systems. This work supports the integration of emotionally enriched action observation paradigms into neurorehabilitation, offering novel strategies to simultaneously target motor and affective dysfunctions in PD.