Typically, problems with balance and coordination (ataxia) are noticed first. (In fact, “ataxia” means incoordination.) The affected person has trouble walking and this difficulty gradually worsens. Falls occur with increasing frequency. As time goes on, the use of a cane, walker, and eventually, a wheelchair will become necessary. Within a few years of onset, slurred speech (dysarthria) is typical due to inability to coordinated movements of the lips, cheeks, tongue, vocal cords, diaphragm, etc. Also, within a few years of onset, coordination of hands and arms becomes impaired. Fine motor skills such as handwriting and fastening buttons are affected first; eventually basic daily tasks such as feeding and dressing become difficult. Abnormal tracking movements of the eyes are common. In the later stages of the disease, difficulty swallowing (dysphasia) results from inability to control muscles in the mouth and throat and aspiration pneumonia may become a life-threating issue.

Recurrent seizures affect 20 percent to 100 percent of those afflicted with SCA10. The seizures are usually seen after the ataxia symptoms first appear. Most commonly recognized are generalized motor seizures, but complex partial seizures also have been seen.

Some individuals with SCA10 have additional symptoms such a mood disorders; weakness or loss of feeling in the feet, legs, or hands (peripheral neuropathy); cognitive dysfunction; and mild pyramidal signs such as overly active reflexes (hyperreflexia) and/or Babinski sign (when the sole of the foot is tickled, the big toe reflex turns up instead of down).