Many people, if they know anything about Parkinson’s disease (PD), think it is a disorder that just affects movement – causing tremors and symptoms that relate to slowness of motion and unsteadiness. Most do not realize that the disease also affects the brain and its ability to learn, remember and control behavior.
Parkinson’s starts in the brain, the control center for everything related to the body. How the brain learns, the ability to multi-task, forgetting words, and the reaction time between when the brain pulls a memory forward and when it comes out of the mouth (tip of the tongue) are just a few of the cognitive functions affected by the disease. Memory may also be affected by the use of medications prescribed to control the symptoms.
One interesting side effect of the disease may be the loss of control over compulsive behavior, such as pathological gambling or shopping out of control.
The disease itself is cause by the loss of the brain cells that produce dopamine, one of the brain chemicals that aids in communication between the cells (neurons). A low level of dopamine in the regions of the brain that control movement and coordination (basal ganglia) is believed to be the cause of the disease. Many believe that some kind of brain trauma, like concussions, may initiate the process that starts the cells to die off.
Medications prescribed to control the disease include those that contain L-dopa, a raw material known to produce dopamine naturally, and drugs that imitate the action of natural dopamine on brain cells (agonists) that are in charge of motor control.
There is a growing need, however, for the non-motor symptoms to be addressed, such as depression, lightheadedness, incontinence, loss of smell, nerve pain, memory loss and dementia.
The National Institute of Neurological Disorders and Stroke (NINDS) met in 2001 and again in 2006 to discuss research into non-motor symptoms of PD. “In both summits, patient advocates and the clinical community identified it as one of the most important under-addressed areas for patients with Parkinson’s disease,” reported neurologist Debra Babcock, M.D., who heads the NINDS program on Cognitive Neuroscience that funds research on non-motor Parkinson’s symptoms. “What’s worse is that some non-motor symptoms are actually aggravated by the treatments used for the motor symptoms.” She added that more research is needed to understand this aspect of the disease, yet less than 5% of the grants issued for Parkinson’s research are earmarked for cognitive dysfunction.
According to neurologist Melissa J. Nirenbert, M.D. of New York’s Cornell Medical College who is an expert on impulse control disorders, at least 14%-17% of PD patients taking dopamine agonists experience impulse control disorders – such as eating, sex, shopping, gambling, etc. Some experience “punding,” or repetitive, purposeless behavior – like sorting objects for no apparent reason. Often the compulsion has to do with a behavior the patient has enjoyed previously in moderation. If the patient would admit to their problem, before it becomes a financial or embarrassing disaster, the medications can be adjusted to cut down or totally eliminate the compulsion.
Recently another anomaly in brain function has been uncovered in Parkinson’s patients – a change in the way they learn. Most people learn by the rewards vs. punishment system – we get rewards for doing something right, and punished when we do wrong. Remarkably, people with PD not taking dopamine-boosting medication learn better when they are punished for wrong choices, rather than being rewarded. The proper medication can tip the scales tip back to where they should be.
At the moment there are not tests that can determine whether a patient has a learning or compulsive disorder, but hopefully in the near future one will be developed that would not depend on the patient to supply accurate information (Due to embarrassment many neglect to inform their physicians until a tragedy takes place that forces them to.).
About the Author:
Ron White is a two-time U.S.A. Memory Champion and memory expert. As a memory speaker he travels the world to speak before large groups or small company seminars, demonstrating his memory skills and teaching others how to improve their memory, and how important a good memory is in all phases of your life. His CDs and memory products are also available online at BrainAthlete.com.
Sources:
Memory Loss & The Brain – How Parkinson’s Disease Affects the Mind: http://www.memorylossonline.com/winter2010/mind_parkinsons.html
