A 15 year-old boy, who had been ill in bed with pervasive cognitive impairment, poor intelligence, global aphasia, disuse muscular atropy, etc since the age of 11 years is reported under the impression of juvenile general paresis. His mother and an elder brother also had positive responses to serologic tests for syphilis. Brain computed tomography showed marked dilatation of ventricles without sulcal enlargement, which was interpreted as communicating hydrocephalus rather than cerebral atropy. He showed some improvements of intelligence and cognitive functions after intramuscular penicillin administration and ventriculoperitoneal shunt. However, it was not good enough to say that his daily living activities in general had improved.