Patients in the conventional treatment group will be given 15 minutes of walking training in addition to the 45 minutes of conventional Parkinson's rehabilitation program. Patients in the conventional treatment group will be trained in flexibility (lumbar extensors, hip flexors, hamstrings, pectorals), balance (weight transfer, static balance with stress loading) coordination (rotational and bilateral activities), respiratory (thoracic expansion, respiratory control), strength (hip circumference, abdomen, back extensors), stabilization, posture (chin tuck, scapular adduction) exercises will be given and the number of repetitions will be adjusted according to patient performance.

Walking training to be given to the conventional group will include walking in different directions, walking with arm swing, walking over blocks, stopping and restarting walking, and changing direction activities.

Patients in the virtual reality group will be given a 45-minute conventional Parkinson's rehabilitation program similar to those in the conventional group, followed by 15 minutes of virtual reality walking training. Patients in the virtual reality group will be trained in flexibility (lumbar extensors, hip flexors, hamstrings, pectorals), balance (weight transfer, static balance with stress loading) coordination (rotational and bilateral activities), Respiratory (thoracic expansion, respiratory control), strength (hip circumference, abdomen, back extensors) stabilization, posture (chin tuck, scapular adduction) exercises will be given and the number of repetitions will be adjusted according to patient performance. Virtual reality applications increase the sense of reality in the individual with enriched virtual environments where sensory inputs are increased and provide the opportunity to perform activity training with a rich variety of tasks.

Patients will be treated 4 days a week for 8 weeks in accordance with their assigned group.

The presence and severity of freezing in patients will be evaluated with the Freezing of Gait Questionnaire. It consists of six items and each item is evaluated with a 5-point Likert scale. In the scale, which was adapted into Turkish by Candan et al., the score range is 0-24 and high scores indicate that the condition associated with frostbite is poor.

The balance of the patients will be evaluated with the Biodex Balance System. Postural stability and fall risk will be evaluated.

The Timed Get Up and Go Test (TUG) will be used to assess functional mobility. The TUG, which includes walking and turning functions, has been shown to be highly reliable and valid for individuals with Parkinson's disease). The person to be tested sits on a chair at normal height. With the command "Go", the person is asked to get up from the chair and walk 3 m forward at a normal walking speed and then return and sit back on the chair. It is usually administered twice and the average time is recorded. The person is allowed to use an assistive device (if available) and this is noted.

Quality of life will be assessed with Parkinson's Disease Questionnaire (PDQ-8) developed specifically for individuals with Parkinson's disease. This validated questionnaire consists of eight questions to assess mobility, activities of daily living, emotional well-being, disease stigma, social support, cognition, communication and physical discomfort . In the questionnaire, the status of the person in the last month is questioned. The total score is between 0 and 100, with lower scores indicating better perceived health status due to the disease.

The Trail Making Test (TMT) will be used to assess executive functions. The TMT measures executive functions such as working memory, complex attention, planning and set switching and requires visual-spatial processing and motor skills. TMT , A and B It consists of two parts. Part A of the TMT, which is an executive function test, evaluates the processing speed based on visual scanning ability, while part B evaluates the ability to change the setup between stimulus sets and to follow the sequentiality. Cangöz et al. determined the standardized values of the test for people over 50 years of age.