Parkinson’s and Cognitive Decline

Most people with Parkinson’s experience cognitive impairment to some degree. Cognition generally refers to the brain processes through which we discover and understand the world around us, and how we apply that knowledge.

Mild changes in cognition may be present as early as the time of diagnosis but often will not interfere with a person’s ability to function at home and work they may not even be noticeable.

Cognitive imperilment is a bit difficult to define, because it covers several different mental skills and activities including: perceptions; storing and retrieving memories; learning; language; forming concepts; solving problems; planning activities; and abstract thinking.

Person with Parkinson’s may feel distracted or disorganized, have difficulty planning and carrying through tasks. They may have difficulty focusing in situations that require divided attention, like a group conversation and feel overwhelmed by having to make choices. They may have difficulty remembering or have trouble finding the right words when speaking.

The same brain changes that lead to motor symptoms can also lead to decline in memory and thinking. Stress, depression and prescription drugs, can also contribute to these changes.

Cognitive decline in people with Parkinson’s is different from dementia. Dementia is a more severe loss of intellectual abilities which interferes with daily living so much that a person may not be able to live independently. Recent studies suggest that many people with Parkinson’s will eventually develop a mild form of dementia as the disease progresses, often many years after their initial diagnosis.

Causes of Cognitive Changes

One cause of cognitive decline in people with Parkinson’s that we know of is a drop in the level of dopamine, a neurotransmitter that is involved in regulating the body’s movements. However, the cognitive changes associated with dopamine declines are typically mild and limited. Two other chemical messengers (neurotransmitters)— acetylcholine and norepinephrine – may also be causing cognitive decline of people with Parkinson’s.

Effects of Cognitive Changes

The cognitive changes that come with Parkinson’s early on are often limited to one or two mental areas, and their severity will vary from person to person.

The areas most often affected include: Forming concepts, planning, creating goals, anticipating consequences, strategizing and evaluating progress.