Ataxia is a disabling neurological condition of impaired movement coordination that can result from damage to a structure in the brain called the cerebellum. Individuals with Ataxia have trouble controlling their balance when standing. They also have difficulty walking, coordinating reaching movements with their arms, speaking, and controlling the movements of their eyes.
Cerebellar Ataxia can occur as a result of many neurological disorders – e.g., stroke, multiple sclerosis, congenital brain malformations, and conditions triggered by an abnormal immune system response to cancerous tumors. It can also be the result of a host of genetic conditions, called Spinocerebellar Ataxias (SCAs), that cause a progressive degeneration of the cerebellum and, in some cases, the surrounding structures of the brainstem and midbrain. While SCAs run in families, gene mutations during a person’s lifetime can also cause conditions that lead to cerebellar degeneration without a family history. The National Ataxia Foundation estimates that, in the United States, around 20,000 people are currently living with SCAs, and that tens of thousands more are affected by recessive and sporadic forms of Ataxia1. Degenerative genetic SCAs are incredibly difficult to treat. There is currently no widely effective medication or other disease-modifying treatment (e.g., brain stimulation implants) for these conditions. Advances in gene therapies have spurred optimism that SCAs may one day be curable, but until then, rehabilitation therapy remains the only option for individuals to manage their symptoms.
Given that Ataxia can impair almost all body movements, it should come as no surprise that rehabilitation therapy for the condition involves a multidisciplinary approach. Neurologic physical therapy is commonly employed to help individuals learn to compensate for deficits in standing balance, walking, and arm control, and to strengthen a person’s muscles to combat physical fatigue. Vestibular therapy is helpful for difficulties with controlling balance and eye movements. Finally, speech-language therapy can help individuals experiencing slurred speech and difficulty swallowing.
While rehabilitation therapy has been shown to benefit individuals with Ataxia, many people experience mixed outcomes, particularly in physical therapy. The underlying reason is not fully understood, but it is generally thought to result from the interaction of two factors: (1) the progressive nature of SCAs, and (2) the fact that many current physical therapy approaches rely on learning and movement control strategies that involve the cerebellum. With respect to the latter, interventions that attempt to leverage motor learning often emphasize movement errors that can spur the nervous system to adapt in a way that relies on the cerebellum. Other techniques that hinge on high cardiovascular intensity often encourage individuals to move fast, which can drive feedforward mechanisms of movement control that also depend on the cerebellum. Indeed, the reliance on cerebellar learning and control mechanisms is likely a key factor in why these interventions are successful in other neurologic populations where the cerebellum is intact. However, novel approaches are needed to maximize benefits for people with Ataxia due to their impaired cerebellar function.
Neuroscience and neurorehabilitation research have greatly advanced our understanding of how the cerebellum contributes to movement control. In recent years, this work has also shed light on how to design behavioral training interventions to leverage learning and control mechanisms that do not depend so heavily on the cerebellum. Research studies have shown that these new behavioral training interventions hold promise for improving outcomes in people with degenerative Ataxias2,3. While further research is needed to translate these interventions to clinical settings and uncover how to optimize them for training different movements (e.g., standing balance and walking versus reaching), we are closer to a future with targeted physical therapy for Ataxia than we have ever been before. Yet, this future will depend on continued federal research funding, particularly for the clinical trials needed to properly test the efficacy of novel physical therapy interventions, the costs of which often exceed the funding capacity of private foundations. As we enter September, and Congress returns from recess to debate substantial proposed funding cuts to the National Institutes of Health4, a critical funder of rehabilitation clinical trials, we must remember the role that rehabilitation can play in improving the lives of people with Ataxia and advocate for continued funding of neurorehabilitation research.
References
1. National Ataxia Foundation. What is Ataxia? https://www.ataxia.org/what-is-ataxia/.
2. Therrien, A.S., Wolpert, D.M., Bastian, A.J. (2016). Effective reinforcement learning following cerebellar damage requires a balance between exploration and motor noise. Brain. Jan;139(Pt 1):101-14. doi: 10.1093/brain/awv329.
3. Therrien, A.S., Statton, M.A., Bastian, A.J. Reinforcement Signaling Can Be Used to Reduce Elements of Cerebellar Reaching Ataxia. Cerebellum. 2021 Feb;20(1):62-73. doi: 10.1007/s12311-020-01183-x.
4. Vought, R.T. Director, Executive Office of the President, Office of Management and Budget, Washington, DC. Fiscal Year 2026 Discretionary Budget Request. May 2, 2025. https://www.whitehouse.gov/wp-content/uploads/2025/05/Fiscal-Year-2026-Discretionary-Budget-Request.pdf
Other Articles In This Series
Article 1: Reclaiming Lives: Neurorehabilitation Research is Critical to Advancing Care
Article 3: Speech-Language Therapy for Aphasia Depends on Research-Backed Techniques
Article 4: Rehabilitation Research for Parkinson’s Disease Deserves a Seat at the Table