[Transient exacerbation of frozen gait by a border zone cerebellar infarction in a patient with vascular parkinsonism: a case report].

We report an 80-year-old man with vascular parkinsonism whose frozen gait was transiently worsened by a cerebellar infarction. Four months before his first admission, he was diagnosed with gastric and esophageal cancer at another hospital, where he had a partial remission by radiotherapy. Two weeks before admission, left hemiparesis due to a lacunar infarction appeared, and he was transferred to our hospital for rehabilitation. Upon admission, he had minimum left hemiparesis and mild frozen gait caused by multiple cerebral infarctions. His condition was improved by physical therapy, and he became ambulatory. Two months later, however, he suddenly became unable to walk and was readmitted. Neurological examination revealed severe frozen gait without other changes. An MRI scan revealed a small new infarction in the left cerebellum between the lateral and the medial superior cerebellar artery area. By supportive therapy, his gait disturbance was gradually resolved except for a slightly short step. Frozen gait is considered a sign of dysfunction of the frontal lobe or nigro-striate system. It is regarded as a component of vascular parkinsonism. Some vascular parkinsonism patients are known to show wide-based gait and some cerebellar signs. It was presumed that our patient's frozen gait might have been exacerbated by impaired equilibrium resulting from the border zone cerebellar infarction.