Non-Ataxic Symptoms Contribute to Gait Dysfunction in Spinocerebellar Ataxias

Objective: To assess the presence and magnitude of non-ataxia neurologic symptoms in spinocerebellar ataxias (SCAs) and their contribution to gait dysfunction.

Background: SCAs are complex and heterogeneous neurodegenerative diseases. While SCAs are characterized by ataxia, they also include non-ataxic symptoms. The presence and magnitude of these symptoms, and the degree to which non-ataxic symptoms contribute to gait dysfunction in SCAs, are not well known.

Design/Methods: 26 patients with SCA were rated using the SARA (Scale for the Assessment and Rating of Ataxia), and received general neurological examinations from movement disorders and neuromuscular experts. Eighteen patients received nerve conduction studies (NCS). No patients were diabetic or abused alcohol, and there were no known patients with vitamin deficiencies or comorbid conditions that would cause gait dysfunction.

Results: Diagnoses of participants were as follows: SCA1=1, SCA2=2, SCA3=5, SCA6=2, SCA7=1, SCA13=1, SCA14=1; sporadic SCA=13. Moderate impairment was noted with gait and balance (=9.90 (3% of maximum possible), speech (=1.46 (37% of maximum possible), limb coordination (=10.44 (39% of maximum possible) and spasticity (=1.92 (24% of maximum possible). Mild to moderate lower limb spasticity was noted in 81% of patients. Decreased lower limb vibratory sensation was noted in 58% (15 of 26) of patients. NCS was suggestive or showed evidence of peripheral neuropathy in the vast majority of these patients (83%). Thirty percent of patients had mild lower extremity weakness. Worsening symptoms of spasticity, weakness, vibratory and position sense, and pin sensibility were strongly correlated with higher 25' walk times (r=0.57) and the SARA total score (r=0.54).

Conclusions: Non-ataxia symptoms, including spasticity, sensory,and motor dysfunction contribute to gait dysfunction in SCAs. Patients should be assessed in a systematic fashion to identify these symptoms. Further research is needed to determine the impact of treating non-ataxic symptoms on the overall function of patients with ataxia.