Cognition & Parkinson’s Disease: The Patient’s Perspective


Cognition is a broad term that encompasses everything from general knowledge and memory to problem solving, decision making, and comprehension. But how does Parkinson’s affect one’s cognition?  The Parkinson Alliance, through its latest survey, answers that question from the patient’s perspective. Over 1,500 people with Parkinson’s participated in the survey, including nearly 400 who had DBS surgery. The survey report provides a better understanding of this complex topic, and offers recommendations pertaining to cognitive functioning in individuals with PD. You can read the complete report here.

One area that participants noted cognitive changes was in memory and how the duration of their disease and age affected perceived memory.  In fact, there are “normal” types of memory problems that happen to all people, regardless if they have PD or not.

Harvard Medical School has a fascinating article entitled, “Improving Memory: Understanding age-related memory loss” in their Patient Education Center. In part, it addresses some memory issues that are normal.  These include transience, or the tendency to forget facts or events over time; absentmindedness; blocking, such as something being on the tip of your tongue; misattribution, such as when you have the right memory but the wrong source (e.g., we saw that movie on Tuesday, when it was Wednesday); suggestibility, which relates to the vulnerability of your memory to the power of suggestion; bias; and persistence, meaning those memories that one cannot forget like those someone with PTSD may experience.  Most fascinating was the lengthy section on why memory fades and what you can do to help keep your brain healthy.  These recommendations, for example, include getting a good night’s sleep, staying socially active, continuing to learn, and managing your stress, among other things.

People with PD, however, do tend to have more problems with working memory (such as not remembering where keys are placed) and retrieval (such as not remembering an appointment).  The University of California, San Francisco, offers an educational video entitled, “Coping with the Cognitive and Behavioral Symptoms of Parkinson’s Disease” on their Parkinson’s Disease Clinic and Research Center website.  The video was presented by Dr. Katherine Possin at a conference on PD.  The good news is that these types of memory problems can be helped with different copying strategies, which she details.  For example, some strategies include writing things down, using a calendar, using an electronic reminder, and setting up a daily routine, among other things.


Examples of memory strategies

Also of note in our survey report is that the vast majority of participants indicated they had not been prescribed medications for cognition difficulties.  However, many of those who have been prescribed medications reported a perceived benefit.  But, non-medication based therapies are also useful in improving cognition as are physical exercise, reading, social relationships, learning a second language, listening to music, interacting with pets (such as service dogs), and learning to play an instrument.

If you are newly diagnosed, I recommend that you request a neuropsychological evaluation test to obtain a baseline of your cognition.  Also be sure to monitor and treat sensory changes, for example your vision and hearing.

Read Cognition & Parkinson’s Disease: The Patient’s Perspective. Please let us hear from you on this topic.

Margaret Tuchman and her blogging partner Gloria Hansen

Cognition: A prominent non-motor symptom in Parkinson’s disease

by Jeffrey Wertheimer, Ph.D., ABPP-CN, our Chief Consultant and Chief of Neuropsychology Services at Cedars-Sinai Medical Center, LA, CA.

Cognitive changes can impact people’s everyday lives as much, and sometimes more than, the physical symptoms of PD.  While discussing this topic with Margaret Tuchman, our next survey topic was developed.  The Cognition and Parkinson’s Disease survey is now available at our website. The objective of this survey is to deepen our understanding about the perspective of individuals with PD pertaining to cognition and its relationship to day-to-day activities. Anyone diagnosed with Parkinson’s should take this survey by clicking here.

Cognition includes the ability to choose, understand, remember, and use information. More specifically, cognitive functions involve:

  • Attention and concentration
  • Speed of processing
  • Processing and understanding information
  • Initiating, planning, organizing, dual tasking, and sequencing
  • Reasoning, problem-solving, decision-making, and judgment
  • Controlling impulses and desires and being patient and calm
  • Memory
  • Communication (i.e., expression and comprehension)
  • Visuospatial processing – (perception of the spatial relationships among objects within the field of vision; visual scanning)

Although cognitive difficulties in individuals with PD can vary in pattern, affecting to a greater or lesser extent different domains of cognition, a typical pattern for individuals with PD involves reduced processing speed, executive dysfunction (difficulties with initiation and managing complex information), difficulties with attention (i.e., working memory), memory, and complex visual scanning/visuospatial processing.  Cognitive impairment in PD also varies in severity. Although cognitive impairment in PD exists on a continuum of severity, it is often divided into two categories (albeit an oversimplification): Mild cognitive impairment and PD dementia, based on the extent to which the impairment interferes with activities of daily living. Mild cognitive impairment refers to cognitive decline that does not significantly interfere with activities of daily living, social engagements, or occupational functioning. In contrast, “PD dementia” involves cognitive impairment in 2 or more cognitive domains that result in interference with daily function (separate from motor disturbance that interferes with independent performance in activities of daily living).

Cognitive difficulties may be present from the early stages of PD, and in most cases, cognitive difficulties get worse over time. While physicians are increasingly recognizing the importance of addressing cognitive and other non-motor symptoms, many still primarily focus on treating the motor symptoms of PD.  Cognitive changes may go under-assessed and undertreated or even untreated, despite its high prevalence.

Cognitive changes in PD can be attributable to multiple causes. Indeed, PD itself can cause changes in cognitive processing. Importantly, however, cognition can be impacted by medication effects (dopaminergic medications related to “on” vs “off” states; non-PD medications), sleep disturbance/fatigue, psychological distress (i.e., depression and anxiety), and pain.  It is very important that treatment providers understand how to address factors that impact cognition, and even prevent and directly treat cognitive difficulties.  It is equally important that people with PD and their families understand what types of changes to look for in order to communicate concerns to their treatment providers.  Cognitive difficulties can be addressed by an interdisciplinary treatment team, such as a neurologist, neuropsychologist, speech therapist, and occupational therapist. Increased awareness and treatment of cognitive difficulties can lead to improved quality of life for people with PD and their families.

In order to facilitate treatment, assessment of cognition is crucial. Mode of onset and the course of symptoms, the context within which they develop, as well as the presence of co-existing medical illnesses and possible medication effects that can contribute to cognitive difficulties should be assessed and guide the approach to intervention. As for intervention, a thoughtful approach tailored to the individual is indicated. In some cases, treatment may not be necessary. In others, behavioral intervention (i.e., scientifically proven approaches to cognitive rehabilitation; addressing psychological factors) may be the primary intervention, while in other scenarios, behavioral intervention coupled with pharmacological intervention (medication changes or medications intended to treat cognition) may be beneficial.

Again, anyone diagnosed with Parkinson’s should take our survey on cognition by clicking here.  The information you provide will benefit individuals with PD and caregivers as well as treatment providers so that they can better help you. Please know that all information you provide will be kept strictly confidential.

Cognitive Rehabilitation for Executive Dysfunction in Parkinson’s Disease

Calleo, J., Burrows, C., Levin, H., Marsh, L., Lai, E., York, M. (2012) Cognitive Rehabilitation for Executive Dysfunction in Parkinson’s Disease , Parkinson’s Disease, vol. 2012, Article ID 512892, 6 pages

The purpose of the review was to determine whether or not cognitive rehabilitation has potential to improve cognitive skills and quality of life in patients with cognitive dysfunction in PD.  Click here to download a PDF of this review.

Click here to read the abstract.

Predictors of cognitive and psychosocial outcome after STN DBS in Parkinson Disease.

Smeding HM, Speelman JD, Huizenga HM, Schuurman PR, Schmand B. Predictors of cognitive and psychosocial outcome after STN DBS in Parkinson Disease. , 2009 May 21. [Epub ahead of print]

The purpose of this article was to look at the effects of DBS STN on cognition, mood, and quality of life in people with Parkinson’s disease (PWP) as well as to evaluate any predictive factors for such changes.    The researchers tested two groups, one that had PD without DBS and another that had PD and underwent DBS STN surgery.  Each group was tested at baseline and then 12 months later.  No significant differences were found at baseline testing between the two groups on cognitive testing.  Twelve months after surgery, the DBS STN group showed improvement in their motor scores as well as a reduction in usage of levodopa.  In regard to the cognitive testing the DBS group showed decline, as compared to the control group, in the areas of verbal fluency (naming items as fast as one can that are from a category or that start with a letter; this finding is common), immediate and delayed memory, a Stroop task (a difficult task requiring naming the color of ink that a word is printed in, while ignoring the word itself), reading speed, and visuospatial reasoning.  Regarding the mood and behavior questionnaires, they found that the DBS STN group had more improvement in their quality of life as compared to the control group regardless of whether or not they experienced change in cognitive functioning.  It is notable that although there was a decline noted in scores on research measures, not all of the PWP that experienced change were able to detect a difference in their everyday lives.  As the findings of cognitive decline after DBS STN has been mixed, the authors suggest replication of this study, and continued attention is needed to this area.

The researchers also wanted to examine possible predictors of cognitive decline and quality of life in PWP.  They found that those PWP who had impaired attention, advanced age, and did not respond well to levodopa at baseline were more likely to experience cognitive decline after DBS STN.  They also found that how the PWP responded to levodopa prior to surgery was the best predictor of improvement in quality of life after surgery.

The authors concluded that DBS STN is an efficacious treatment for improved motor symptoms of PD as well as quality of life in the PWP.  However, the treatment has been found to have adverse effects that PWP need to know about before undergoing such treatment.  They discuss that physicians should also pay attention to premorbid factors before surgical intervention that may help predict who is more likely to have such adverse cognitive events after the surgery.

Click here to read the abstract.

Cognition and mood in Parkinson’s disease in subthalamic nucleus versus globus pallidus interna deep brain stimulation: The COMPARE Trial.

Okun MS, Fernandez HH, Wu SS, Kirsch-Darrow L, Bowers D, Bova F, Suelter M, Jacobson CE 4th, Wang X, Gordon CW Jr, Zeilman P, Romrell J, Martin P, Ward H, Rodriguez RL, Foote KD. Cognition and mood in Parkinson’s disease in subthalamic nucleus versus globus pallidus interna deep brain stimulation: The COMPARE Trial. , March 13, 2009

The purpose of this article was to compare the effects of DBS-STN vs. DBS-GPi, in regard to mood and cognition.  The authors looked at various settings and stimulation parameters of both devices with patients off medication so they could evaluate the stimulators alone.  Patients were also given various cognitive and mood measures prior to surgery and then again 7 months after surgery.  It is notable that 7 patients did not continue the study after surgery due to adverse events (could not tolerate protocol, hemorrhage, and pneumonia related death [one]).  We would refer the reader to the supplementary tables in the article for more specific information about adverse events for those that remained in the study, although most were mild and did not last long.  However, the authors noted that the STN group had more adverse events than the GPi group.  

Generally, this article showed that there were few differences in mood and cognition between STN and GPi when both groups were at their optimal settings.  They concluded that the verbal fluency finding (naming as many words that start with a specified letter as fast as one can) likely is a result of the surgery as the effect was still there when the stimulator was not on for the DBS-STN group.   The authors also discussed that their findings suggest that the target of DBS may best be done based on individual patient characteristics (e.g. cognitive issue, behavioral concern, medication reduction, etc.).  It also showed different stimulator settings and areas that should be avoided in individuals with specific complaints (e.g. less energetic, less happy, etc.), which is very beneficial information for those doing the placement as well as the programming of the devices in improving the care and quality of life of individuals with DBS STN or GPi.

Click here to read the abstract.

Cognitive and behavioural effects of chronic stimulation of the subthalamic nucleus in patients with Parkinson’s disease

Daniele, A., Albanese, A., Contarino, M.F., Zinzi, P., Barbier, A., Gasparini, F., Romito, L.M.A., Bentivoglio, A.R., & Scerrati, M. (2003) Cognitive and behavioural effects of chronic stimulation of the subthalamic nucleus in patients with Parkinson’s disease , 74, 175-182

Motor, cognitive, behavioral, and functional assessments were undertaken in 20 patients with PD before implantation and then at 3, 6, and 12 months afterwards. Nine patients were also examined at 18 months after surgery. On all postoperative assessments, there was an improvement in parkinsonian motor symptoms, quality of life, and activities of daily living while off antiparkinsonian drugs. A significant postoperative decrease in depressive and anxiety symptoms was observed across all assessments for most of the patients. Following implantation, three patients developed transient manic symptoms with hypersexuality.

Click here to read the abstract.

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