Visuospatial/Perceptual Abilities

The purpose of this research is to determine how deep brain stimulation (DBS) for Parkinson's disease affects attention and visuospatial function. Additionally, this study will evaluate how deficits in visual attention are associated with freezing of gait (FOG) in Parkinson's disease. There is currently no reliable treatment for FOG and little is understood about the underlying reason this occurs. Some recent research has found that stimulating the right side of the brain seems to improve FOG. The right side of the brain is also paramount for visual attention, which is why investigators are conducting this study.

The goal of this observational study is to evaluate the changing body perception of amputees aged 18-65 years using prostheses through different personal perspectives of the right-left distinction. In addition, we aimed to examine the relationship between possible changes in body perception and visual spatial perception and neurocognitive performances. The main questions that this study aimed to answer are as follows: 1. Is there a difference between the amputee group and the control group in terms of parameters related to body perception? 2. Is there a difference between the amputee group and the control group in terms of neurocognitive skills? 3. Is there any difference between the amputee group and the control group in terms of visual spatial perception abilities? To examine whether changes in body perception in amputees affect neurocognitive performance, visuospatial perception and perspective perception and the relationship between them will be compared with a healthy control group. The assessments to be applied to both groups can be summarised as follows: * Demographic information such as age, gender, and education level will be recorded. * Mini-mental state test will be used to assess the cognitive level. * Edinburgh Handedness Scale will be used to determine the dominant side. * Right-left discrimination and personal perspective perception will be assessed using a desktop programme. * The clock drawing test and Benton line orientation test will be used to visual spatial perception. * A computer based program called The Central Nervous System (CNS) Vital Signs Neurocognitive Test Battery will be used to asesses neurocognitive abilities.