Objective: The aim of this study was to assess prevalence and severity of autonomic dysfunction in patients with SAOA, defined as a subacute or progressive onset of ataxia after 40 years of age in the absence of a positive family history. Dysautonomia and extra-cerebellar symptoms in SAOA were compared with those observed in patients with MSA-C.

Background: Sporadic adult-onset ataxia (SAOA) is characterized by the absence of identifiable genetic or acquired causes and is therefore a diagnosis of exclusion following comprehensive clinical evaluation. Severe and progressive autonomic failure is the hallmark of multiple system atrophy, cerebellar type (MSA-C), whereas autonomic dysfunction in SAOA remains insufficiently characterized.

Method: Participants were enrolled at the Neurology Clinic, UCCS, University of Belgrade, Serbia. Acquired and most frequent genetic causes of adult-onset progressive ataxia (SCA 1,2,3,6,7, and 17, Friedrich’s ataxia, RFC1, FGF14) were excluded. Ataxia severity, extracerebellar signs and cognitive impairment were assessed using standardized clinical scales, including SARA, CCAS and INAS. Autonomic dysfunction was evaluated using the SCOPA-AUT questionnaire, orthostatic standing test, and post-void residual (PVR) urinary volume measurement.

Results: Study comprised 37 patients, including 19 with SAOA and 18 with MSA-C. SAOA patients had significantly longer disease duration (p<0.001) and more frequent spasticity (p=0.009) than patients with MSA-C. Groups did not differ in the total SARA and CCAS scores. Gastrointestinal and thermoregulatory symptoms were present in 84.2% of SAOA patients, urinary symptoms in 73.7%, cardiovascular symptoms in 63.2%, and pupillomotor symptoms in 26.3%. SCOPA-AUT total score did not differ between groups. Among SCOPA-AUT domains, thermoregulatory dysfunction was more severe in SAOA (p=0.018) and no other differences between SAOA and MSA-C patients were observed. Orthostatic hypotension was significantly more frequent in MSA-C at both 1 and 3 minutes of standing (p=0.017 and p=0.003, respectively). PVR urinary volume was significantly lower in SAOA than in MSA-C (p=0.001).

Conclusion: While autonomic dysfunction is a common feature of SAOA, severe cardiovascular and urinary autonomic failure remain characteristic of MSA-C.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/assessment-of-dysautonomia-in-patients-with-sporadic-adult-onset-ataxia/