Insight into Parkinson’s 2020, Day 2, Part 2 – Conference notes

Insight into Parkinson’s 2020, Day 2, Part 2 – Conference notes

Insight 2020 is the largest online conference for people with Parkinson’s disease (PD), their caregivers, and those who work with the PD community. It took place this year on April 1-3, and covered a wide range of topics, from living positively to the latest PD research. We at Stanford Parkinson’s Community Outreach attended all three days of the virtual conference and took notes on some of the talks that seemed most interesting or relevant to our audience. Highlights from Day Two of the conference are below. Due to length, we have split the notes into two separate blog posts. Below is Part 2 of Day 2 of the conference.

To see the agenda for the full conference, visit the Insight 2020 event website here.

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Balance control in Parkinson disease

Speaker: Prof. Laurie King, Associate Professor of Neurology and Physical Therapist at Oregon Health and Science University

Insight into Parkinson’s Conference, April 2, 2020

Notes by Lauren Stroshane, Stanford Parkinson’s Community Outreach

Falls are a major concern in those with Parkinson’s disease (PD) and the most worrying outcome of the balance issues that are common in PD. Prof. King spoke about the various aspects of normal balance, and how these become impaired in those with PD.

Constraints limiting balance in PD:

  • Biomechanical rigidity: Stiffness in the limbs and trunk.
    • Stooped, flexed posture develops over time.
  • Anticipatory and reactive postural adjustments: the activities our body does automatically right before moving.
    • For example, the ability to anticipate taking a step, by shifting your weight over to one leg; this is often decreased in those with PD.
    • A reactive response could be catching yourself when you start to fall.
  • Sensory integration: Ordinarily, we use the visual, proprioceptive, and vestibular systems together to maintain balance.
    • Those with PD must rely more on the visual system as the others become increasingly impaired.
    • In conditions where visual information is less available, such as getting up to go to the bathroom at night, those with PD are more likely to lose their balance.
    • Those with PD also tend to have impaired sense of movement from their limbs and feet (poor kinesthesia).
  • Cognitive changes: Many with PD develop some degree of cognitive impairment over time, which also increases the risks of falling.

When does someone with PD start to have problems with balance? Typically, multiple domains of balance have started to decline by the time someone is having balance problems and falls.

The limit of stability refers to the area in which a person’s body can lean in various directions without falling over.

Gait issues in PD are multi-factorial, involving bradykinesia (slowed movement), difficulty with transitions such as turns or changes in the environment, and decreased arm swing. You might see significant slowing if an individual with PD is trying to walk and have a conversation at the same time.

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Freezing of gait: why and how?

Speaker: Dr. Aasef G. Shaikh, Assistant Professor of Neurology at Cleveland Medical Center

Insight into Parkinson’s Conference, April 2, 2020

Notes by Lauren Stroshane, Stanford Parkinson’s Community Outreach

Freezing of gait (FOG) occurs when an individual – most often, someone with PD – finds that their feet “stick” to the floor or shuffle forward in short, unbalanced steps, while they are trying to walk forward. Many with PD will experience some degree of FOG over the course of the illness; it can make it very difficult to get around, and often precipitates falls.

FOG is a context-dependent phenomenon: it doesn’t happen in every situation. Scenarios that commonly trigger FOG include:

  • Walking in a narrow hallway
  • Going in and out of a doorway or threshold where the flooring changes
  • Walking in a busy room with many people around, such as a grocery store

What is the common element in all these scenarios that leads to FOG in those with PD? It is not just a motor issue. Gait and balance in PD involve multiple systems. 

Action and perception are closely linked; if you perform a repetitive physical task and you perceive that you did it well, such as taking a step forward, then your brain interprets this as successful and repeats it. There seems to be a mismatch in PD between the perception of walking versus the action of walking. Postural changes and muscle rigidity often alter one’s center of gravity and ability to maintain normal balance; these also play into the likelihood of falls and freezing.

Visual and spatial processing difficulties are also common in PD and contribute to FOG and falls. If your brain is struggling to determine whether a dark shape at the end of the hall is a shadow, a table, or a dog, this can trigger freezing. Changes in depth perception, blurred vision, and double vision can occur in PD as well and are called binocular disparity. Tiny eye movements called saccades are normal for our regular visual processing; in PD, these saccades are often abnormal, making it more difficult for those with PD to scan their visual environment. Interestingly, those with Deep Brain Stimulation (DBS) implants seem to have improved eye movements compared with those who do not have DBS.

Putting all these factors together, as a person with PD is walking forward in their environment, impaired visuospatial processing and visual problems make it difficult to get a correct read on their surroundings, while motor issues and impaired ability to perceive their own movements make it difficult to know where in space their own body is. This mismatch seems to confuse the brain, leading to FOG as the brain struggles to figure out what to do.

The speaker wrapped up the discussion with the possibility that DBS in the subthalamic nucleus (STN) could perhaps be leveraged to improve perceptual non-motor function in those with PD. This is an area that requires more scientific research, which Prof. Shaikh’s lab is currently working on.

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One of the presentations (“Tired of trouble sleeping?”) covered similar content as a recent talk by Dr. Emmanuel During of Stanford Neurology that was summarized on the Stanford Parkinson’s Community blog:

Sleep and Parkinson’s disease – Meeting notes

March 19, 2020