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  • Writer's pictureNatalie Wilcox

Thawing Freezing Gait with a Painted Staircase Illusion

Mileha Soneji was a product designer in the Netherlands when her uncle was diagnosed with Parkinson’s disease. As a product designer she hoped to develop a product that would help with his everyday tasks. She visited her uncle to interview him on what types of tasks a new device may assist with. After a largely unfruitful interview she remained at his home, watching him struggle to walk even with a walker and taking small hesitant steps whenever a turn was necessary. Her uncle lived in a two-story house and Mileha suddenly became very concerned as she realized that her uncle who could barely walk between rooms had to go up and down stairs everyday. So, she asked him how he managed it and he responded that he would show her. Upon reaching the top of the stairs he moved his walker out of the way and walked down the stairs without any difficulty. Moving quickly around turns and stepping with confidence. She was astounded and had found her target for product development. After much trial and error, she developed a staircase illusion, made of paper that she laid on the floor in front of her uncle. He proceeded to walk effortlessly across the illusion just as he had on the stairs, but froze when he came to the end. Eventually she created paths of staircase illusions allowing him to move easily through his home (Soneji, 2017).

Although an amazing story of a simple design creating a large impact, it generates many more questions, the first being: how did it work?

Mileha’s uncle had a symptom found in approximately 26% of Parkinson’s patients called freezing of gait (FOG). FOG is typically a later stage Parkinson’s symptom, which often begins with turning hesitation and may progress to freezing where they cannot move forward or start walking (Bloem, Hausdorff, Visser, & Giladi, 2004). Often, people with FOG describe the feeling of freezing as having “their feet get glued to the ground”(Giladi & Nieuwboer, 2008). The cause is still unknown although the most recent research points to a dysfunctional supraspinal locomotor network (Pozzi et al., 2019). The supraspinal locomotor network is made up of the primary motor cortex, the supplementary motor area, the parietal cortex, the basal ganglia, the subthalamatic nucleus and the cerebellum. Together, these areas coordinate the initiation and planning of a movement as well as maintaining balance. When studying FOG, the subthalmatic nucleus is an important structure as it initiates the conduction of a signal to the spinal cord telling it to relay a particular movement message to the muscles. Damage to this area may result in the difficulty to initiate movement (Pozzi et al., 2019).

So how does a painting on the floor override a damaged subthalmatic nucleus?

The answer resides in the cortical visual areas of the brain. When we see a set of stairs it is easy to understand that we must lift our feet higher to get to the next step. This visual information travels from the cortical visual areas of the brain to the basal ganglia, which is one of the main motor control areas of the brain, on to the supplementary motor cortex, and onwards to the spinal cord and the rest of the supraspinal locomotor network (Janssen, Soneji, Nonnekes, & Bloem, 2016). Once the initial movement onto the stairs is initiated, the subthalmatic nucleus no longer needs to initiate each step, rather the movement becomes continuous from one step to the next (Pozzi et al., 2019). This same concept can be applied to someone with FOG riding a bicycle; once the movement is initiated it can be repeated in the exact same fashion, appearing effortless.

However, someone cannot ride a bike or walk on a painted surface forever, this is why designers are looking to technology to adapt the concept that Soneji discovered to a wider platform. The use of smart glasses or augmented reality with wearable sensors could allow 3D cueing to be applied to any situation (Janssen et al., 2016).


Bloem, B. R., Hausdorff, J. M., Visser, J. E., & Giladi, N. (2004). Falls and freezing of gait in Parkinson's disease: A review of two interconnected, episodic phenomena. Movement Disorders, 871-884.

Giladi, N., & Nieuwboer, A. (2008). Understanding and treating freezing of gait in parkinsonism, proposed working definition, and setting the stage. Movement Disorders, 423-425.

Janssen, S., Soneji, M., Nonnekes, J., & Bloem, B. R. (2016). A painted staircase illusion to alleviate freezing of gait in Parkinson’s disease. Journal of Neurology, 1661-1662.

Pozzi, N. G., Canessa, A., Palmisano, C., Brumberg, J., Steigerwald, F., Reich, M. M., . . . Isaias, I. U. (2019). Freezing of gait in Parkinson’s disease reflects a sudden derangement of locomotor network dynamics. Brain, 2037-2050.

Soneji, M. (Producer). (2017, November 17). Mileha Soneji: Can Simple Innovations Improve The Lives of Parkinson's Patients? Ted Radio Hour. Retrieved from

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