Frontal ataxia: a frequent but underrecognized disorder in the spectrum of ataxias

Ataxia comprises a heterogeneous group of disorders with multiple clinical and etiological presentations. The frontal subtype, in particular, is poorly defined and often misdiagnosed, reflecting both its complex historical evolution and lack of formal diagnostic criteria.

To evaluate clinical and epidemiological characteristics of a sample of patients with ataxia under follow-up in a private neurology clinic.

We evaluated 48 patients diagnosed with ataxia over a 4-month period and followed them for 1-year in a private neurology clinic in southern Brazil. Clinical, neuroimaging, and laboratory data were analyzed. Patients were classified according to clinical and etiological subtypes based on criteria defined by the authors.

Frontal ataxia was the most frequent presentation (n = 15; 31.3%), predominantly affecting elderly patients with systemic arterial hypertension, diabetes mellitus, and MRI evidence of small vessel disease. These patients had a later disease onset (mean: 75.9 ± 8.8 years), lower SARA scores, and a nonprogressive course compared with degenerative cerebellar ataxias (p < 0.0001). No correlation was observed between the severity of small vessel disease (Fazekas scale) and gait ataxia (rs = -0.28, p = 0.31). Hereditary ataxias, particularly spinocerebellar ataxias (SCAs), were the second most frequent group, followed by atypical Parkinsonian syndromes.

Frontal ataxia emerged as a frequent and underrecognized subtype in routine neurological practice. These findings underscore the need for increased awareness and the development of evidence-based diagnostic criteria to better define and distinguish it within the spectrum of ataxic disorders.