This study aims to explore how young adults, older adults and people with Parkinson's disease (PwP), perceive their abilty to cross obstacles while walking, and how this perception is related to their actual performance of obstacle crossing and disease-related motor and cognitive impairments. The study will explore this percepeption and the actual performance in different walking environments(floor, synthetic grass turf). Understanding how people perceive obstacles may help improve rehabilitation methods and reduce the risk of falls. The study will take place at the Motor Performance Laboratory, University of Haifa, and will include walking tasks, eye-tracking measurements, and motor and cognitive assessments.

This study investigates the role of affordance perception - the ability to perceive opportunities for action - during obstacle crossing in people with Parkinson's disease (PwP). Falls are highly prevalent in PwP, often resulting from tripping over obstacles. While previous research has mainly focused on gait impairments, this study uniquely examines the perceptual stage that precedes movement and the association between perception, cognition, and motor performance.

Participants will include 60 PwP and 120 healthy adults (60 older adults and 60 young adults). All participants will perform walking tasks involving obstacle crossing under different environmental conditions (e.g., different obstacle heights and surfaces). Prior to walking, participants will judge whether they can safely cross the obstacle. Eye-tracking glasses will measure visual exploration patterns to assess how participants scan the environment. Additionally, walking variables such as speed and step length, will be recorded using wearable sensors.

The study will explore:

1. Differences in affordance perception between PwP and healthy adults.
2. Associations between motor and cognitive impairments and affordance perception in PwP.
3. How affordance perception relates to gait performance during obstacle crossing.

Results from this study may help to develop new intervention strategies aimed at improving safe walking and obstacle negotiation in PwP.

Inclusion Criteria:

• Participants aged 20 to 80 years.
• Ability to walk independently outdoors without assistive devices.
• For Parkinson's Disease (PD) group: Diagnosis of PD confirmed by medical records.
• For healthy control groups: No neurological or orthopedic conditions affecting gait.

Exclusion Criteria:

• Feezing of gait (for PD group only), based on a score greater than 0 on the Freezing of Gait Questionnaire.
• Severe visual impairment that cannot be corrected with glasses or lenses.
• Cognitive impairment, defined as a score below 18 on the telephone-based Mini-Mental State Examination (MMSE).
• Any orthopedic condition, pain, or other medical condition that may affect walking, based on self-report.

The study population will include three groups: (1) people with Parkinson's disease (PwP), aged 60-80 years, diagnosed by a physician and able to walk independently outdoors; (2) healthy older adults aged 60-80 years without neurological or orthopedic conditions affecting gait; and (3) healthy young adults aged 20-30 years without neurological or orthopedic conditions affecting gait.

Participants will be recruited from the community, from clinical settings (for PwP), and through university-based recruitment systems (for young healthy adults).

Individual participant data (IPD) will not be shared. Data collected in this study will only be used by the study investigators for research purposes, in accordance with the approved study protocol and ethical guidelines.