Parkinson's disease is a disorder that is most known for motor impairments of tremor, slowness in moving, and loss of balance. Patients with Parkinson's disease also suffer from non-motor symptoms, such as mental, memory, or mood disturbances. Dopamine has been identified as key chemical that is lacking in the brain of a person with Parkinson's disease. Acetylcholine has been identified as a deficient chemical in the brain of persons with Alzheimer's disease, which is a neurological disorder characterized by mental and memory problems.
Recent research from Dr. Bohnen's group at the University of Pittsburgh has shown that patients with Parkinson's disease, even when not demented, have a lack of acetylcholine chemicals in the brain that is even greater than in patients with Alzheimer's disease. Dr. Bohnen has also found that the lack of acetylcholine chemicals in the brain of patients with Parkinson's disease is associated with specific cognitive problems of attention and executive functions. Executive functions are important for planning and decision making in daily life.
Dr. Bohnen's present study proposes to measure the activity of dopamine and acetylcholine in the brain of patients with Parkinson's disease using PET imaging. He then proposes to evaluate how these brain chemicals affect cognitive functions and activities of daily living in these patients.
The main hypothesis of the proposal is that a significant lack of acetylcholine chemical activity in the brain in patients with Parkinson's disease is the cause of significant cognitive problems. Such cognitive difficulties can lead to difficulties with activities of daily living that cannot be purely explained by the typical motor impairments of this disorder. If this hypothesis is true then further research would be needed to evaluate the use of medications that stimulate acetylcholine (in addition to drugs that act on the dopamine brain system) to improve cognitive functions and activities of daily living in patients with Parkinson's disease and hopefully, reduce caregiver burden for their family members.
Dr. Bohnen identified changes in cholinergic function associated with postural and gait disturbances and cognitive decline. Examination of PD patients with dementia is ongoing.