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Understanding Freezing of Gait (UnFOG) : A scale for measuring and subtyping FOG

Updated: Apr 8

Have you ever experienced a sudden feeling of being glued to the ground while trying to walk? If you are an individual suffering from Parkinson's disease(PD), you might be familiar with this frustrating sensation known as Freezing of gait (FOG). It's a common disabling motor symptom in PD that can seriously impact your quality of life.

FOG doesn't always happen the same way for everyone. It can show up in different situations and be triggered by various things. By understanding these different triggers, we can classify FOG into specific types, like freezing when trying to start walking, while turning, or freezing in tight spaces like doorways. Why does this matter? Well, personalization of treatment is very important for people with PD. Different types of FOG are associated with different mechanisms, and may be benfited with different treatment. By understanding the specific type of FOG a person experiences, doctors can choose the best treatment option for them. It means better care and improved quality of life for patients dealing with FOG.

The tools we currently have for measuring FOG fall short when it comes to classifying it into different subtypes. While tests like UPDRS, FOGQ and NFOGQ are helpful for screening, they don't record the details about how FOG presents in different situations. The Freezing of Gait Severity Tool does record activities and situations that trigger FOG. However, to really understand FOG and its subtypes, we need a tool that looks at not only physical aspects but also how the brain works in different situations. These tests can help narrow down which parts of the brain might be involved in causing FOG. That’s where UnFOG scale comes into play

UnFOG is a scale designed to understand different subtypes of FOG based on specific triggers. It combines both motor and non-motor (cognitive) assessments to get a holistic picture of FOG. With this information, doctors can make better decisions about how to treat FOG in a way that’s practical, affordable, and easy for individuals with FOG.

UnFOG scale starts with evaluation of anxiety levels using scales like Geriatric Anxiety Scale and Part C of Parkinson’s Anxiety Scale. It is important because being anxious can make FOG worse and increase the risk of falling. We will also ask them about their fear of falling using FES-I scale. Following these, we will conduct cognitive tests to identify which brain area is affected and its correlation with specific subtypes of FOG. Then, we will do a motor test by asking them to walk in six different situations that often trigger FOG, like turning, walking through doorways, sit to stand from chair. These tests will first be done with simple walking and then with walking + doing mental calculations. UnFOG gait task can also be video recorded to identify FOG duration and number of FOG episodes. The relationship between cognitive dysfunction and FOG subtypes can be demonstrated by determining the brain areas involved in cognitive tasks and specific FOG subtypes.

UnFOG has the potential to help us better understand different types of Freezing of Gait and how they might change over time. For example, if multiple cognitive tests show impairment, one can expect their FOG might get worse too. Knowing this can help doctors make better decisions about how to help their patients and ways to improve their walking.

To understand UnFOG better, refer to the preprint of UnFOG. And to know more about FOG and how our product WALK can aid in reducing FOG, you can see https://www.lifesparktech.com/post/walk-a-wearable-mobility-aid-for-parkinsons-disease


1. Preprint of Understanding Freezing of Gait (UnFOG) : A scale for measuring and subtyping FOG https://zenodo.org/records/8409822

2. Characterization of freezing of gait subtypes and the response of each to levodopa in Parkinson’s disease https://onlinelibrary.wiley.com/doi/10.1046/j.1468-1331.2003.00611.x

3. Evidence for subtypes of freezing of gait in Parkinson’s disease https://movementdisorders.onlinelibrary.wiley.com/doi/10.1002/mds.27417

4. Freezing of gait: moving forward on a mysterious clinical phenomenon. https://www.sciencedirect.com/science/article/pii/S1474442211701430?via%3Dihub

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