Abstract
BACKGROUND: Functional movement disorders (FMDs) are commonly classified along canonical non-ataxic movement disorder patterns, creating a potential blind spot for frequently observed ataxia-like presentations. At the same time, normal diagnostic findings and episodic symptom variability in some cerebellar ataxias predispose to an incorrect FMD diagnosis. CASES: We present three cases that illustrate pitfalls in the differential diagnosis of ataxia. First, a patient treated for presumed immune-mediated cerebellar ataxia was diagnosed with FMD based on clinical signs. Next, a patient with intermittent and inconsistent symptoms was diagnosed with FMD after extensive exclusionary workup, but was then found to have a novel type of spinocerebellar ataxia. The third patient had a genetically confirmed spinocerebellar ataxia but developed additional functional motor symptoms. CONCLUSION: Differentiating cerebellar ataxias from FMDs and recognising mixed presentations is essential. Enhanced clinical awareness and systematic diagnostic evaluation are crucial to avoid misdiagnosis and ensure optimal treatment.