While ataxia itself may be apparent (ie, if you drink too much, your friends, or the state trooper, can identify your temporary ataxia), diagnosis of its cause is often much more difficult.
It may involve a number of medical disciplines, including your primary care physician, a neurologist, a genetic or movement specialist; in addition, lab and xray specialists.
Since there are many possible causes, and since many symptoms appear similar, medical professionals will conduct a thorough and disciplined approach in order to eliminate and/or identify possible causes to make a diagnosis.
This approach will include:
So, while ataxia itself may be apparent, diagnosis of its cause can be quite involved.
From Diagnosing Ataxia to Health