A New Assessment Tool for Ataxia Syndromes: The "STAND" (Scale To Assess Ataxia and Neurologic Dysfunction)

Objective: To evaluate a new ataxia rating scale, the STAND (Scale To assess Ataxia and Neurologic Dysfunction).

Background: Neurodegenerative ataxias, such as spinocerebellar ataxia (SCA) may include non-ataxic symptoms. There is a need for an assessment tool to better evaluate non-ataxic symptoms in patients suffering from neurodegenertive ataxias. The Scale for the Assessment and Rating of Ataxia (SARA) is a valid scale, but does not assess these symptoms. The “INAS” (Inventory of Non-Ataxia Symptoms) “counts” nonataxia symptoms, but does not rate them. We conducted a pilot evaluation of a new assessment tool called the “STAND” to better evaluate non-ataxic and ataxic symptoms.

Design/Methods: The STAND is a semi-quantitative 109 point scale that tests gait, balance, speech, coordination, tone, peripheral motor, and sensory function. Two movement disorders neurologists administered the SARA and the STAND during one visit and a neuromuscular expert performed nerve conduction studies (NCS) in SCA and Friedreich's ataxia patients. Interrater reliability was examined using intraclass correlation coefficients (ICC). Correlation between STAND and SARA totals and sub-scores were tested using Spearman's correlation test. Internal consistency was assessed by Cronbach's α.

Results: Thirty-seven ataxic patients participated in the study to evaluate the scale, and 25 patients received NCS. The scale showed good internal consistency (Cronbach's α=88). Ataxia components of the STAND were strongly correlated with the SARA (r for total ataxia score = 0.88). Interrater reliability for the overall scale was excellent (ICC=0.97) and was similar for sub-scales (gait and balance ICC=0.99; speech ICC=0.84; limb coordination ICC=0.91; tone ICC=0.76; peripheral motor system ICC=0.78; peripheral sensory ICC=0.87). Peripheral sensory scores correlated with the presence and degree of abnormalities noted by NCS (r=0.75).

Conclusions: The STAND's quantification of non-ataxic neurologic symptoms should provide greater diagnostic and prognostic utility than scales that assess ataxic symptoms alone.