Cerebellar atrophy is primarily a radiological finding, typically observed on cranial CT or MRI scans that show cerebellar shrinkage. The extent of cerebellar atrophy does not necessarily correlate with clinical manifestations; the severity of the atrophy may not align with the severity of clinical symptoms. If cerebellar atrophy occurs without any clinical symptoms and the patient remains agile and strong, then it is considered not severe. However, some diseases that cause cerebellar atrophy can be quite severe, such as multiple system atrophy, which has a subtype called olivopontocerebellar atrophy. This condition can lead to significant gait instability and limb ataxia, causing issues like inaccurate finger-to-nose testing and unstable object handling. The symptoms are definitely very severe, and the prognosis is very poor. Additionally, long-term alcohol consumption and alcohol poisoning can also cause cerebellar atrophy, which is also quite severe. In such cases, abstaining from alcohol and administering B vitamins are necessary for treatment, but the prognosis remains poor.