Freezing of Gait in Parkinson’s disease

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A frequently suggested topic for this blog is freezing of gait. (Feel free to suggest a topic of your own.) Our readers want to know more about this potentially disabling symptom so today I will discuss what is freezing of gait, why it happens, tips, strategies, and walking devices that can help, as well as potential future treatments.

What is freezing of gait?

Freezing of gait is an abnormal gait pattern that can accompany Parkinson’s disease (PD) as well as other parkinsonian disorders in which there are sudden, short and temporary episodes of an inability to move the feet forward despite the intention to walk. In a sense, you’re stuck. This results in the characteristic appearance of the feet making quick stepping movements in place. However, while the feet remain in place, the torso still has forward momentum which makes falls unfortunately common in the context of freezing of gait.  For some, these episodes can simply be frustrating, annoying and perhaps embarrassing; for others freezing of gait can become incredibly disabling and lead to injury.

Freezing of gait episodes tend to occur least often when walking on an unobstructed, straight path. Any deviation from that can induce freezing – for example, when you first try to start walking, when you go to make a turn, or try to navigate around obstacles or through narrow spaces – any of these can cause you to get “stuck.”

The particular triggers for one person may be different than for another.  An episode is typically very brief, often lasting only 1-2 seconds, although they can last longer. Freezing of gait can be affected by anxiety, so if a person feels rushed (e.g. under a time constraint to board an elevator before the doors close), freezing may be particularly prominent.

Why does freezing of gait occur?

It is not completely clear why some people with PD experience freezing of gait and others do not. Research suggests that there is a relationship between freezing of gait and cognitive difficulties. The brain circuitry that controls gait is extremely complex and involves multiple connections between various parts of the brain, including:

• areas in the front of the brain that plan and initiate movement
• areas of the basal ganglia where the dopaminergic neurons that refine and control movement are found
• areas in the brainstem which modulate movement and wakefulness

Freezing of gait seems to be caused by short-lasting episodes of inhibition of these brain circuits that coordinate gait. The specific abnormalities that cause the problem may differ from person to person.

Treating freezing of gait for people with Parkinson’s

Freezing of gait episodes often occur when a person is under-medicated and can improve with increased amounts of their PD meds, usually carbidopa/levodopa. However, as mentioned earlier, the brain abnormalities that lead to freezing of gait are very complex, so giving more dopaminergic medication is only part of the solution. In fact, some people have what is referred to as ON freezing. This means that freezing of gait episodes occur even when other PD symptoms are well treated with their medication regimen.

Cueing, or the introduction of an external sensory stimulus to facilitate movement, has been identified as a way to “break” a freezing episode. Terry Ellis, PhD, PT, NCS, Director of the APDA National Rehabilitation Resource Center at Boston University, and Tami DeAngelis, PT, GCS, compiled this list of cues that can be used to get out of a freezing episode:

Ten Tips to put the Freeze on Freezing!

1. Try another movement – raise an arm, touch your head, point to the ceiling; then re-start
2. Change direction: if you can’t move forward, try stepping sideways first, and then go forward
3. Carry a laser pointer in your pocket; when you freeze – shine the laser in front of your foot and step on the light – this visual cue can help you re-start.
4. Visualize an object on the ground in front of you and try to step over it.
5. Wear a metronome on your belt or carry a small one in your pocket – turn it on and the external beat can help you re-start.
6. Try humming a song and time your re-start with the beat of the music
7. Count “1-2-3-go” and then step forward
8. Shift your weight from side to side to help initiate taking a step
9. March in place a few times and then step forward
10. Don’t fight the freeze by trying harder to step forward – shift your attention from moving the legs to moving the arms – then resume walking forward

While these methods can be helpful to get out of a freeze that is already underway, physical therapy techniques that incorporate these types of cueing strategies are utilized to reduce freezing of gait overall. Rhythmic auditory cueing is one such technique which utilizes rhythm and music to improve gait in PD and other neurologic diseases.

Walking aids to help with freezing of gait

Often freezing of gait cannot be overcome with medication adjustment and physical therapy, and a walking aid needs to be introduced for safety and walking support.

There are many types of walkers that are available for people with walking difficulties. Here is a simple guide:

• Basic walker – this is usually just a metal frame without wheels
• Wheeled walker – a metal frame with wheels. The wheels may be on two or four legs and the wheels may swivel or be fixed
• Rollator – a walker with swivel wheels on all four legs and hand brakes. The brakes typically need to be engaged for the walker to stop. Often the rollator has a seat and a basket for convenience.

A common concern with all these walkers is that there either is no braking system or the braking system must be engaged in order for the walker to be stopped. Therefore, if a freeze occurs with the feet stuck to the floor, and the person is not fast enough to engage the brake, the walker will continue to move, potentially precipitating a fall.

The U-step walker was designed specifically for this scenario. Although it may not help every patient with PD, it has some features that are worth knowing about. The U-step walker has a reverse braking system which means that without engaging anything, the walker is in the braked position and the wheels will not turn. A lever must be gripped or pressed (depending on the model) in order for the wheels to turn. Therefore, if a freeze occurs, the walker should stay stable. In addition, the resistance of the wheels, which controls the rolling speed, is adjustable. Finally, the walker can be ordered with a laser light and sound cueing module which can be used to interrupt a freeze as discussed above.

Your physical therapist can help you determine the walking aid that is best-suited for your specific situation.

Future of freezing of gait treatments

Various research approaches may transform how freezing of gait is treated in the future. Cognitive training strategies are being studied to determine if they improve freezing of gait. Another approach is the development of wearable technology systems that can detect an imminent freeze and then automatically deploy a sensory cue. Novel deep brain stimulation (DBS) targets are also being developed as a method of controlling freezing of gait.

APDA invests in research that may lead to new treatments for the gait disorders of PD. Here are some examples:

Christopher Bishop, PhD, at Binghamton University in Binghamton, NY, is studying an area of the brainstem known as the pedunculopontine nucleus, which plays a key role in movement and wakefulness. It has been an experimental DBS target for relief of freezing of gait and PD-related gait disorders with mixed results. Dr. Bishop is probing the specific functions of this key brain area to determine how they impact PD symptoms.

Aasef Shaikh, MD, PhD, at Cleveland VA Medical Center, University Hospitals Cleveland, and Case Western Reserve University in Cleveland, OH, is studying the complex interactions of various neurologic systems, their effects on gait and balance in PD, and how they can be modified by DBS. The systems that Dr. Shaikh studies include vision, eye movements, the inner ear/vestibular system, and proprioception.

Tips and takeaways

• Freezing of gait is a complex PD gait disorder in which people get “stuck” in place and temporarily have a hard time moving their feet forward.
• For some people, freezing of gait can become a major source of disability.
• There are options for treating freezing of gait, including adjusting your PD medications, using tools like sensory cueing, and using a walking aid.
• If freezing of gait is an issue for you or a loved one, be sure to speak to your neurologist and physical therapist about it. They can help you learn how to get “unstuck” and better manage freezing of gait episodes.
• Future treatments may involve cognitive training, freezing of gait prediction systems and novel DBS strategies.
• APDA supports researchers who are focused on solving the problem of parkinsonian gait disorders. Read here about the vast array of APDA-funded research.