Freezing of gait, or FOG, is said to affect approximately 7% of individuals with early Parkinson’s disease (PD) and more than half of those with advanced PD.1 This is due to the loss of postural reflexes, which are automatic movements that help us maintain equilibrium and balance when we are standing upright. FOG is usually defined as an onset of not being able to start stepping forward, with no apparent cause, and can be exacerbated by stress or distraction.1 FOG can look like trembling of the legs, shortening of steps or shuffling, or feeling like one is unable to move their feet.2 It’s one of the most debilitating aspects of PD and can increase fall risk. While there is no known cure for this, there are potential treatments for it, and ways to prevent FOG are being explored.
Potential treatments for FOG
Levodopa is considered the “gold standard” of treatment for PD. The drug levodopa is synthesized into dopamine by the brain. It’s usually combined with carbodopa, which helps more dopamine get to the brain, rather than being immediately converted into dopamine while in the bloodstream.3 It helps improve movement, including FOG. High-dose levodopa in particular has been shown to reduce FOG when compared to placebo or low-dose levodopa.
Another possible drug therapy that can be of benefit to those with PD with FOG are the monoamine oxidase B inhibitors (MAO-B inhibitors). These drugs decrease the normal functioning of the enzyme monoamine oxidase, which helps to break down dopamine in the brain. When these drugs are given, dopamine lasts longer in the brain before breakdown or reuptake. Selegiline and rasagiline are two MAO-B inhibitors that are approved by the FDA to treat PD. Rasagiline was shown to improve duration and frequency of FOG, and those patients taking selegiline showed slower motor decline.3
Methylphenidate (MPH) is perhaps best-known for its use with people with ADD/ADHD. It inhibits dopamine transporters. Low doses of MPH might improve gait, as well as FOG. There are conflicting studies as to whether the drug is more effective as the dose is increased, and more research needs to be done – but the research so far is promising.
In addition to drug therapy, because FOG can arise from a multitude of causes and involves various systems, a multidisciplinary approach can be appropriate for treatment. Occupational therapy, rehabilitation, and physiotherapy all have their place in treating FOG.2 Neurological treatments like deep brain stimulation (DBS) might also be an option for some people, as it can also provide symptom relief for things like rigidity and tremor.2
Right now, there is no known way to prevent FOG in a person with PD. It can be challenging to think of how to prevent FOG, because it doesn’t present the same way in every person, and it can also be triggered by a variety of things. This suggests that there is a unique neural aspect that causes FOG.2 Often times, by the time FOG is bad enough to cause problems for a person, it’s also very hard to treat. The important thing, then, is to find precursors to FOG to help prevent the condition before it gets to be bothersome or difficult to manage.
Cognitive deficits have also been shown to be associated with FOG, so it’s worth looking at whether addressing cognitive deficits or difficulties improves FOG. Cognitive training in particular, when combined with regular dopaminergic medication, has been shown to be highly beneficial in reducing the severity of FOG.2
It’s important to address FOG before it becomes challenging for a person with PD, since it is easier to manage if targeted earlier. It may be difficult for a person to admit to problems with gait, but the earlier these issues are accepted and addressed, the better chance you have of managing it with less difficulty. Talk with your doctor about your concerns regarding FOG, preventative measures you might be able to take, things to watch out for, and what treatments would be an option. Each person is different, and your doctor will be able to take your personal disease history and health into account when discussing course of treatment with you.
Zhang L-L, Duff Canning S, Wang X-P. Freezing of gait in Parkinsonism and its potential drug treatment. Current Neuropharmacology. 2016; 14(4): 302-306. doi: 10.2174/1570159X14666151201190040.
The future of freezing of gait in Parkinson’s: Exploring potential treatments and preventive strategies. Neurology Advisor website. https://www.neurologyadvisor.com/movement-disorders/parkinson-disease-freezing-of-gait-treatment-prevention/article/772436/ Published June 12, 2018. Accessed July 28, 2018.
Levodopa. Parkinson’s Foundation website. http://parkinson.org/Understanding-Parkinsons/Treatment/Prescription-Medications/Levodopa 2018. Accessed July 31, 2018.
DeVito L. Could MAO-B inhibitors slow Parkinson’s Disease progression? The Michael J. Fox Foundation for Parkinson’s Research website. https://www.michaeljfox.org/foundation/news-detail.php?could-mao-inhibitors-slow-parkinson-disease-progression March 10, 2017. Accessed July 31, 2018.