SCA Functional Index (SCAFI)

The SCAFI is a composite score for spinocerebellar ataxia, combining three timed tasks that between them cover the main things ataxia takes away: walking, hand coordination, and speech.

An 8-metre walk is timed at maximum speed. The 9-hole peg test is timed for each hand separately, measuring manual dexterity. The PATA rate counts how many times a person can repeat the syllables "pata" in ten seconds, measuring speech articulation speed. Each task is performed twice and averaged. Raw times are converted to rates, then to Z-scores against a reference population, and the three Z-scores are averaged into the final index. Higher means better performance.

• Validation Study

Licensing Notes: Materials and administration guidance are posted freely by the Ataxia Study Group.

Learn More: . A Z-score of 0 equals the reference population mean at baseline, so the index is meaningful only relative to whichever population it was standardised against — it does not give an absolute score the way a 0-to-30 scale would. Trials typically define their own baseline population and report change from there.