Cognitive and Psychiatric Impairment in Parkinson

February 6, 2017
Lee Nourse

Can we see changes in the brain that correspond to cognitive difficulties? Research presented at AAN 2016 offers compelling information.

Jennifer G. Goldman, MD, MS presented compelling evidence that we view changes in the brain that correspond to cognitive difficulties at American Academy of Neurology’s 68 Annual Meeting in Vancouver on April 18, 2018.

Not only can we see alterations in the brain, we can better understand the nonmotor changes patients go through.

The ability to see biomarkers allows us to understand more about cognitive decline. We can better grasp the nuances of PD cognitive impairment, including PD dementia and psychosis.

Structural imaging markers of PD cognition show there is atrophy in some regions of the brain, including the frontal and temporal regions. More severe atrophy corresponds to greater progression of the disease.

Recognition

Nonmotor symptoms often precede motor symptoms and typically trigger a decline in quality of life (QOL). Early PD symptoms, according to Parkinson’s Disease Foundation, include: 

• sleep disturbances

• depression

• fear and anxiety

• cognitive issues (memory, slowed thinking, confusion)

These symptoms can, of course, lead to increased morbidity and caregiver stress. The decreased quality of life, then, extends to those caregivers.

Cognitive issues greatly impact PD. According to another study, 84% of PD patients suffer from cognitive decline.

Defining and identifying cognitive impairment is complex. In attempting to recognize PD, we have to be cautious that the behavior we are assessing does not stem from sleep deprivation or mood disorders, as both can influence cognition and be present without PD.

Another marker, specifically for PD dementia, is amyloid.

“The story on amyloid is still unfolding,” commented Dr. Goldman. While there is more amyloid present in the brain with PD dementia, Alzheimer patients present with even more of the substance. 

Depression and Anxiety

Newly diagnosed Parkinson patients may have cognitive changes that are easy to miss if we don’t ask patients the right questions.

Depression, which is common, may precede motor symptoms in PD. Forty percent of patients suffer from the disorder. Mood symptoms often present are sadness, irritability, decreased general interest, and anxiety.

MRI brain scans have shown evidence of depression. Researchers can see, for example, neuronal degeneration and orbitofrontal dysfunction, decreased DA transporter activity, and frontal blood flow. They’ve also seen evidence related to glucose metabolism.

An interesting study in 1999 reported a female subject’s facial expression demonstrated significant despair 4.16 seconds after receiving electrical stimulation. She returned to smiling 1.20 seconds after the stimulator was turned off. This study sheds light on how PD-related changes in the brain can directly cause depression.

Anxiety is also common, yet too often unrecognized. It ranges in prevalence from 5% to 40% in patients and can include depression, panic disorders, phobias, and obsessive-compulsive disorder.

Strategies

Dr. Goldman reported an emerging set of trials exists. Treatments will vary widely, according to the complexity of the patients’ symptoms.

There is a need for much more research and development in PD. Currently, for example, the only FDA-approved pharmaceutical available for PD dementia is rivastigmine.

Finally, non-pharmaceutical strategies are also being examined. Psychotherapy, diet, yoga, and other exercise could prove to be the best strategy for some people living with PD.

From materials presented during AAN Annual Meeting in Vancouver, British Columbia. Session S122: Nonmotor Manifestations of Parkinson's Disease II. Apr 18, 2016.

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