Clinicians are well aware of the fact that certain lesions of the cerebellum, resulting in marked hydrocephalus, may lead to a pseudo-frontal syndrome which reveals itself in the patient's general disinhibition, behavior changes, uncritical attitude to his condition, and other symptoms structurally close to the impairments manifested in lesions of the frontal lobes. There are grounds to believe that many such cases should be regarded as secondary frontal syndromes. Patients with an injury to the posterior cranial fossa and the secondary frontal syndrome differ from those with the true basal frontal syndrome only in a more critical attitude to their defect. They usually see the arising difficulties and refuse to solve problems if they encounter difficulty in working them out. In performing tests on selective responses, the patient attempted to perform the task prior to being given the instructions and often gave impulsive echopraxic answers.