“Neuropsychological symptoms of Parkinson’s disease” – lecture notes

A neuropsychologist spoke on neuropsychological symptoms of Parkinson’s Disease (PD) at the early-April Insight 2020 conference. Since these neuropsychological symptoms — cognitive impairment, attention, visuospatial processing, executive functioning, apathy, and disinhibition — have relevance for the atypical parkinsonism community, we are sharing the lecture notes here.

Insight 2020 was the largest online conference for people with PD, their caregivers, and those who work with the PD community. Lauren Stroshane from Stanford Parkinson’s Community Outreach attended the virtual conference and took notes on some of the talks that seemed most interesting. Copied below are her notes from a talk by Australian neuropsychologist Dr. Luke Smith.

This excerpt is worth highlighting as we see this same issue in the atypical parkinsonism conditions:

People with PD sometimes describe themselves as having a memory problem. Yet, in the speaker’s experience, many of those people who undergo cognitive testing are actually shown to have a learning problem, not a memory problem. Memory has 3 stages: learning (taking in new information), storage (like a computer; keeping the information), and remembering (retrieving the info when you need it).

This is a good excerpt too as lack of insight is very common in the atypical parkinsonism conditions, especially Lewy body dementia and progressive supranuclear palsy:

Executive functioning is best described as the most complicated aspects of our cognitive function: planning, anticipating the outcome of actions, problem-solving, controlling instinctive responses to stimuli, and having insight into one’s own condition. It is another aspect of cognition that can be impacted by PD. Sometimes the loved ones of those with PD may feel that the affected person is in denial of their condition – but it may just be a lack of insight due to the disease.

Robin

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Neuropsychological symptoms of Parkinson’s disease  
Speaker: Dr. Luke Smith, Clinical Neuropsychologist
Insight into Parkinson’s Conference, April 2, 2020
Notes by Lauren Stroshane, Stanford Parkinson’s Community Outreach

The speaker, Dr. Luke Smith, is a clinical neuropsychologist in Melbourne. He discussed changes in cognition, social cognition, behavior and personality that can occur in those with PD, as well as support options.

Dr. Smith sometimes finds it strange that PD is classified as a movement disorder, since the disease affects far more than just our movement. The basal ganglia, which is the area of the brain most affected by PD, was originally thought to be responsible only for movement. We now know that this part of the brain also greatly impacts how we think, feel, and behave. The frontal lobe and parietal lobes of the brain are also affected in PD; these areas impact “executive” or decision-making function (frontal lobe), and visual processing (parietal lobe).

Minor changes in thinking or memory are called mild cognitive impairment (MCI). This may show up on cognitive testing, but likely is not impacting the individual’s day-to-day life. Those with PD are at higher risk of having MCI.

Parkinson’s disease dementia (PDD) occurs if MCI has progressed into more severe problems in memory or thinking, impacting the person’s ability to perform normal functions like driving a car, managing finances, or cook a meal. Looking at the prevalence of these issues in PD longitudinally, most research suggests that, for those who have lived with PD for ten years or more, about half would probably meet criteria to be diagnosed with PDD.

Changes that can occur in thinking: 

The amount of time it takes for a person with PD to process information often increases. Keeping up with a fast conversation or a rapid-paced movie can become more difficult; it may feel like the world is moving faster around you. Changes in attention and concentration may also occur. Attention span is defined as how much information you can take in at one time; the average amount of information a normal adult can absorb is about 5-7 bits of information at one time without repetition of the information. For those with PD, it may be only 3 bits of information that they can take in at once. Divided attention – often called “multitasking – becomes more difficult for those with PD as well. For some people, working memory – the ability to keep multiple small amounts of new information in your mind at once – is affected as well, manifesting sometimes as difficulty with mental arithmetic.

Visuospatial processing tends to be affected in those with PD. This means the ability to understand visual stimuli. Those who have a dog know that their dominant sense is that of smell; dogs are highly driven by their noses. Similarly, most humans’ dominant sense is our sight. Our eyes take in the raw data and our brain makes sense of that data. For those with PD, the way they interpret that data is no longer working normally. This can manifest, for instance, in difficulty putting together IKEA furniture, or problems for those who make their living as architects, contractors, artists, designers, or others in highly visual fields.

People with PD sometimes describe themselves as having a memory problem. Yet, in the speaker’s experience, many of those people who undergo cognitive testing are actually shown to have a learning problem, not a memory problem.

Memory has 3 stages:

  1. Learning – taking in new information 
  2. Storage – like a computer, keeping the information
  3. Remembering – being able to retrieve that information when you need it

For those in early to moderate PD, often, their memory is fine. It may be that they aren’t taking in as much information to be encoded in their memory storage. When someone has a true memory problem, it is step 3 – remembering the information off the top of your head – that is the issue. For people with PD, receiving a prompt or hint can help recognize the memory, allowing them to retrieve it. This is called recognition memory, and is usually still quite strong in those with PD.

By contrast, Alzheimer’s disease (AD) is another common neurodegenerative disease that affects memory quite differently than PD. Those with AD suffer from deterioration of their long-term memory: who they are, where they live, who their family is. For those with PD, memory often becomes less efficient, but long-term memory remains intact.

Executive functioning is best described as the most complicated aspects of our cognitive function: planning, anticipating the outcome of actions, problem-solving, controlling instinctive responses to stimuli, and having insight into one’s own condition. It is another aspect of cognition that can be impacted by PD. Sometimes the loved ones of those with PD may feel that the affected person is in denial of their condition – but it may just be a lack of insight due to the disease.

Some of those with PD may have trouble recognizing certain facial expressions in others, particularly unhappy or angry expressions. This ability to recognize social cues is called social cognition. Figuring out an idea of why another person may be feeling a certain way is called theory of mind.

Additionally, those with PD may experience something called pseudobulbar affect – the tendency to show excessive emotion in response to outside stimuli, regardless of how they actually feel inside. An example may be crying for no reason, or laughing uncontrollably at inappropriate times.

Changes in behavior and personality can also occur in PD, since these aspects of oneself are controlled in the frontal lobes. Apathy is the most common change that happens in those with PD, and can be quite frustrating for caregivers or family who are trying to motivate the individual to do things they formerly enjoyed. Impulsivity, also called disinhibition, may start to do things without considering the consequences. An example may be rudely commenting on someone’s appearance, when in the past, they would never have done so. 

If you or a loved one are noticing some of these issues, the first thing to do is seek help with a medical professional.

What to do if you notice cognitive changes?

Neuropsychologists, like the speaker himself, are good at working with families to assess cognitive abilities and make recommendations and can administer a standard battery of tests, typically over 3-4 hours. But a primary care doctor or neurologist can also be a good place to start, likely with a cognitive screening test that might take only 20 minutes or so. Among the various cognitive tests out there, the Montreal Cognitive Assessment (MoCA) does a better job of screening for executive dysfunction and other issues specifically seen in PD than some of the other screening tests that may be available, such as the Mini-Mental State Exam (MMSE), which the speaker does not recommend in PD. Occupational therapists, speech therapists, and nurses can be helpful resources as well, for evaluating cognitive changes.

It’s important to consider where you are getting your information; internet searches will turn up lots of different websites that may or may not have accurate information. Instead, contact your local PD association, which will have up-to-date information and resources for these issues. 

There is some good news: In the last 5 years, we now have evidence that cognitive rehabilitation strategies can help when someone experiences memory or thinking issues. Cognitive rehabilitation involves learning and using new memory and thinking techniques and strategies. They do not necessarily improve cognition per se, but they do improve coping abilities and improve a person’s ability to function day-to-day.