Subacute cerebellar degeneration (SCD) is a condition in which the cerebellum, the area of the brain that controls muscle coordination and balance, deteriorates for any one of a number of reasons. This leads to difficulty coordinating complex movements and balance problems. There are two types of SCD: paraneoplastic cerebellar degeneration, which may due to a cancer, and alcoholic/nutritional cerebellar degeneration, which is a result of a lack of vitamin B1. The two types of SCD share the same symptoms, which may include ataxia (coordination problems), vomiting, and difficulty speaking. Treatment varies based on the cause and may include vitamin supplementation or diagnosis and treatment of a cancer potentially causing the disability. People with this condition typically also require physical therapy to manage balance and movement problems.