Electronic Thesis and Dissertation Repository

Thesis Format

Integrated Article


Master of Engineering Science


Electrical and Computer Engineering


Patel, Rajni V.


Parkinson’s Disease (PD) causes force control deficits in upper and lower limbs. About 50% of patients with advanced PD develop freezing of gait (FOG). There is limited research comparing force control in PD with and without FOG, especially in upper limbs. It has been suggested that motor control deficits in PD are related to deficits in kinesthesia, but there is conflicting evidence whether levodopa alleviates kinesthetic deficits. In this thesis, force control was explored using an upper-and-lower-limb haptics-enabled robot in a reaching task, and kinesthesia was investigated using a haptic device in a force discrimination task while participants were on and off levodopa. Similar significant force control deficits were found in upper and lower limbs in patients with FOG compared to those without FOG. However, no significant kinesthetic deficits were found in patients with PD, independent of medication state, suggesting force control deficits may not be attributable to kinesthetic deficits.

Summary for Lay Audience

Parkinson's Disease (PD) is a degenerative neurological disease that causes a range of symptoms, including motor issues such as tremor, rigidity, bradykinesia (slow movement), and gait problems. While levodopa, the gold standard drug for PD, can help with alleviating some symptoms, PD patients experience continuing decline. As PD progresses, patients may develop freezing of gait (FOG), which is when they have trouble initiating or continuing to walk despite the intention to do so. FOG is unpredictable and typically occurs when trying to start walking, turn, or navigate narrow spaces. Levodopa can typically manage FOG, but for some FOG can persist despite treatment (called levodopa-unresponsive FOG). People with PD have measurable motor deficits, specifically in force control, which refers to the magnitude, direction, and speed of force generation. The area of the brain affected by PD is associated with generating both kinesthesia (the body's sense of position, speed, and force) and movements in response to kinesthesia. Because of this, it is thought that PD may also impair kinesthesia, and it is unclear whether levodopa can improve kinesthesia. Recent research has explored the use of haptic devices, which provide force and motion feedback to a user while interacting with a virtual environment to study changes in force control in people with PD with FOG. Not many studies have been done regarding changes in movement in the arms of people with FOG. This study used haptic devices to measure force control in both the arms and legs of people with PD with levodopa-unresponsive FOG, compared to those with PD without FOG and healthy people without PD. The results showed that people with PD and levodopa-unresponsive FOG had greater deficits in force control than those with PD without FOG. However, deficits in kinesthesia were not found in PD patients while on or off levodopa. This suggests that the deficits in force control may not be attributable to deficits in kinesthesia. Although the results presented here are from pilot studies with small numbers of participants, the findings are interesting and warrant further research with larger cohorts.

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Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.