# First steps matter: gait initiation reveals emotion-driven motor compensation in Parkinson's disease

## TL;DR

Emotional cues like happiness help people with Parkinson's disease start walking faster, but the effect varies depending on the type of Parkinson's they have.

## Contribution

The study reveals subtype-specific differences in how emotional cues influence gait initiation in middle-stage Parkinson's disease.

## Key findings

- Emotional stimuli reduced anticipatory postural adjustments and step execution time in both Parkinson's and healthy participants.
- Happiness elicited a stronger motor advantage than fear, but Parkinson's patients showed a diminished benefit compared to controls.
- PIGD subtype individuals showed a weaker motor advantage for happiness compared to the TD subtype.

## Abstract

Parkinson’s disease (PD) disrupts the intricate cognitive, emotional and sensorimotor circuits required for movement. In a recent study, we observed that fear-related embodied stimuli could enhance motor responses in early stage persons with PD (PwPD), potentially by activating neural compensatory mechanisms. In this observational study, we implemented a sensor-based ‘Go/No-go’ gait initiation task involving a response to emotional facial expressions—fear, happiness and neutral facial expressions—to elucidate whether and how emotional cues may drive compensatory mechanisms for motor performance in middle-stage PD. Furthermore, we investigated whether these mechanisms differ between PwPD exhibiting tremor-dominant (TD) or postural instability and gait disorders (PIGD) motor subtypes. By comparing gait initiation parameters between PD participants and age-matched healthy controls, we found that emotional stimuli reduced the duration of anticipatory postural adjustments and the step execution time across both groups, indicating a robust motor advantage. Specifically, happiness elicited a more pronounced advantage than fear, though PwPD displayed a diminished benefit relative to controls. Intriguingly, individuals with the PIGD subtype showed a weaker motor advantage for ‘happiness’ than those with the TD subtype, suggesting subtype-specific differences, possibly reflecting different underlying neural circuitry. Collectively, our findings reveal that while emotional cues generally facilitate gait initiation, fear and happiness exhibit distinct modulatory effects in PD. Compared to our earlier findings, the fear-related motor benefit appears to decline with disease progression, while the happiness-related advantage varies considerably across PD subtypes. These insights highlight the nuanced interplay between emotion and motor control in PD and suggest the use of a cognitive-emotional-sensorimotor integration task as a sensitive predictor for differentiating PD motor subtypes.

Botta et al. report that emotional cues, particularly happiness, facilitate gait initiation in middle-stage Parkinson’s disease (PD) and healthy controls. This advantage is diminished in persons with PD and differs between tremor-dominant and postural instability/gait disorder subtypes, suggesting subtype-specific compensatory mechanisms and a potential role for cognitive-emotional-sensorimotor tasks in differentiating PD motor subtypes.

Graphical Abstract