Podcast Summary: 4D Deep Dive into Degenerative Diseases – Episode 55

“Freezing of Gait with Alice Nieuwboer”

Host: Parm Padgett
Guest: Dr. Alice Nieuwboer, Emeritus Professor in Rehabilitation Sciences, Catholic University of Leuven, Belgium
Date: May 1, 2025

Episode Overview

This episode explores the topic of “freezing of gait” (FOG) in Parkinson’s disease—a complex, frustrating symptom for patients and clinicians alike. Dr. Alice Nieuwboer, a leading researcher in Parkinson's rehabilitation, shares her expertise on FOG's pathophysiology, guiding theories, patient subtypes, clinical assessment, and evidence-based therapeutic approaches. The conversation highlights both scientific uncertainty and practical hope for clinicians working to improve mobility and quality of life in people with Parkinson’s.

Key Discussion Points & Insights

Dr. Nieuwboer’s Background and Interest in FOG

• Dr. Nieuwboer recounts her journey from physical therapy in the UK to her academic and research career in Belgium, focusing on neurorehabilitation, specifically Parkinson’s disease and FOG.
  • “I was forced into that topic by my then supervisor… But once I was forced into it, I never looked back.” (01:42)
• Emphasizes her enduring passion for research and mentorship post-emeritus, balancing involvement and stepping back when needed.

Pathophysiology of Freezing of Gait

• FOG is episodic and unpredictable; the “bottleneck” model is a leading but incomplete explanation.
  • “First of all, we don’t truly understand why we have this very episodic problem... There is a moment whereby within the basal ganglia there is an overload of neural input, and that overload brings on a breakdown of the gait network.” (05:10)
• Multiple brain networks contribute to FOG:
  • Cognitive (e.g., distraction)
  • Limbic (e.g., anxiety, stress)
  • Motor (e.g., turning, adapting gait to the environment)

Notable Quote

“As a physiotherapist, you want to undo complexity and avoid overload. So that is a helpful thought, I think, for dealing with freezing of gait.”
— Dr. Nieuwboer (08:10)

Automaticity, Dopamine, and Subtypes

• Decreased dopamine impairs automatic movements, forcing patients to compensate with attention.
  • “Because people have an automaticity problem, it means that they overcompensate by using attention a lot.” (09:35)
• FOG subtypes (emerging model):
  1. Cognitive overload (dual tasking)
  2. Limbic overload (stress/anxiety)
  3. Motor overload (environmental adjustments/turns)
• Early in Parkinson’s, FOG may respond to medication; later, all three subtypes may converge as disease progresses.

Notable Quote

“Some people may have more difficulty with cognitive overload, others may have more difficulty with limbic overload… eventually... they will have freezing in all three circuits.”
— Dr. Nieuwboer (10:48)

Freezing, Festination, and Variability

• Festination (hastened, shuffling steps) may be a mild or related form of FOG, though definitions and consensus vary.
  • “I think that fascination type, shuffling type movements are part of, say, a more mild form of freezing probably, or is a phenomenon that is related but slightly different.” (14:40)
• FOG varies greatly between patients and within the same individual—making research and clinical management challenging.

Notable Quote

“It is very, very difficult to do this type of research, but very exciting as well at the same time.”
— Dr. Nieuwboer (17:32)

Deep Dive: Freezing of Gait Subtypes

1. Cognitive (Dual Tasking) [18:11]

• Patients freeze more with cognitive load, especially challenging tasks.
  • “There is a correlation between cognitive load and the duration of freezing and the number of freezing episodes.” (18:26)
• Cognitive decline appears slightly more pronounced in freezers, even when controlling for disease severity.

2. Limbic (Stress/Anxiety) [20:26]

• Stress triggers FOG both in anticipation of known triggers (e.g., elevators) and during risky tasks.
  • “It is people that are very sensitive to worrisome thoughts about freezing....patients started to freeze more.” (22:25)
• Stress and cognitive distraction may synergize but are hard to fully separate.

3. Motor (Environmental Adjustments/Turning) [23:27]

• Rapid, complex turns are the most potent and reliable trigger for FOG—even in patients who don’t self-identify as “freezers”.
  • “Performing a 360 turn fast... brings on freezing quite regularly, even in people that do not say that they are a freezer.” (24:34)

Clinical Assessment Practices

Key Assessment Tools:

• 360-degree turn test (with/without dual task, both directions; most sensitive trigger)
  • “It becomes even more sensitive when you also have patients doing a dual task as well during the 360.” (25:43)
• Dual-task Timed Up and Go (TUG) (walking + cognitive task; combines cognitive, motor, stress triggers)
  • “It was also high on our list of situations which triggered freezing of gait.” (27:30)
• Mini-BESTest (for balance assessment)
  • “I would also do items from the mini best test to see whether patients are unstable...” (31:37)
• Questionnaires to understand “hot spots” and specific situations at home where FOG occurs

Clinical Emphasis

“What brings on freezing in this particular patient? … The analysis is more important, in my view, than separating them out necessarily in three subtypes.”
— Dr. Nieuwboer (28:36)

FOG and Falls

• There is a strong relationship between FOG episodes and fall risk; freezing often involves instability and fear.
  • “It is an enormous fall trigger...A moment of freezing for them is also a moment of instability.” (32:39)

Evidence-Informed Treatment Strategies

Key Principles

1. Rescue Strategies

   • Teach patients to stop when freezing begins and then “reset.”
   • Emphasis on weight shifting (side-to-side) to unweight the swing leg:

     “The first thing that they have to learn is to stop wanting to move ... and then try and shift your weight, whereby you then release your swing leg.” (34:38)

2. Cueing Techniques

   • Auditory cues (metronomes, rhythmic music), visual cues, and emerging vibration devices
     • Auditory cues are most practical and adjustable in clinic.
     • On-demand cueing devices still have technical challenges but show promise for reducing both duration and frequency of FOG ([44:45], [47:15])
   • Importance of training patients to wean off cues and maintain rhythm without them:

     “What you want patients to take away from training is that they maintain their gait rhythm even through all kinds of clutter and complexities... Now you keep on going.” (42:19)

   • Internal cueing strategies like “mental singing” are effective; patients can use these discreetly.

     “It can be counting, it can be singing ... singing is very effective.” (43:35)

3. Gait Adaptation Training

   • Frequent practice in complex, variable, environment-rich settings (turns, clutter, changes in speed)
   • Promote adjustments to gait in real-life “hot spot” situations to increase patient carryover

4. Strength, Balance, and Cognitive Training

   • Early and ongoing focus on strengthening balance, lower limb strength, cognitive reserve, and adaptability to potentially delay the onset or worsening of FOG.
   • “Can we postpone freezing...Can we make the brain stronger so that it takes a little bit longer before it comes home?” (48:55)

Notable Quotes & Memorable Moments

• “You cannot undo that part of your brain, you cannot take it out with a neurosurgical technique or so.” – Dr. Nieuwboer on lifelong passion for Parkinson’s research (02:03)
• “There are people that say, no [festination is not FOG], and there are people that say, yes. I belong to the latter group.” (14:34)
• “It is an excellent starting point for therapy...try and almost mimic the situations where they had a freeze.” (29:13)
• On hope and the future:

  “Even the incomplete system was effective...I think there’s hope in that technology will start to become better in detecting freezing episodes.” (47:30)

Timestamps for Major Segments

| Segment | Start Time | |-------------------------------------------------|------------| | Guest Intro & Background | 01:17 | | Pathophysiology of FOG | 05:03 | | Automaticity, Dopamine, and Subtypes | 09:21 | | Festination vs. Freezing, Definitions | 14:07 | | Subtype Deep Dive: Cognitive, Limbic, Motor | 18:11 | | Assessment Tools & Clinical Pearls | 25:43 | | FOG & Falls | 32:20 | | Treatment: Rescue, Cueing, Gait Training | 34:27 | | Vibratory & On-demand Cueing Devices | 38:47, 44:45| | Internalizing Cues, Mental Singing | 42:47 | | Building Resilience, Early Interventions | 48:55 | | Closing Reflections | 51:44 |

Tone & Style

The conversation is expert yet relatable, balancing humility about science’s current limits with pragmatic optimism. Dr. Nieuwboer conveys deep respect for patients’ experiences and a collaborative, hopeful spirit toward research and clinical advances in Parkinson’s care.

Useful For:

• Clinicians seeking fresh strategies for addressing FOG
• Therapists wanting to better predict, provoke, and assess FOG
• Anyone interested in nuanced discussions of Parkinson’s rehab research and its real-world translation