Transcranial Doppler sonographic identification of a subgroup of patients with normal pressure hydrocephalus with coexistent vascular disease and treatment failure.

We report on transcranial Doppler sonography with carbogen reactivity testing of flow velocity as applied to patients with normal pressure hydrocephalus. A subgroup can be differentiated that shows coexistent cerebrovascular disease. The surgical prognosis in these patients is bad. A flow chart demonstrating the proposed clinical examination is presented.