Frontal brain and leptomeningeal biopsy specimens correlated with cerebrospinal fluid outflow resistance and B-wave activity in patients suspected of normal-pressure hydrocephalus.

OBJECTIVE: Normal-pressure hydrocephalus (NPH) is a potentially treatable syndrome with abnormal cerebrospinal fluid dynamics. Meningeal fibrosis and/or obliteration of the subarachnoid space has been suggested as the pathoanatomic basis. The purpose of the present study was to investigate whether meningeal fibrosis causes increased resistance to cerebrospinal fluid outflow (R(out)) and/or increased B-wave activity and whether pathological changes in the brain parenchyma after brain compliance, causing increased B-wave activity. METHODS: The study involved a group of 38 consecutively studied patients with clinical and radiological evidence of idiopathic NPH, for whom a frontal brain biopsy was obtained. For 29 patients, hydrodynamic criteria of NPH were fulfilled and a ventriculoperitoneal shunt was performed. RESULTS: Meningeal fibrosis was found in 12 of 25 biopsies containing arachnoid tissue, but no correlation with R(out) or B-waves was found. Pathological parenchymal changes, most often Alzheimer's disease (10 cases) or vascular changes (10 cases), were found in 21 biopsies, but no correlation with B-waves or R(out) was found. CONCLUSION: The results suggest that leptomeningeal fibrosis is not the only pathoanatomic basis of increased R(out) and/or B-wave activity in patients with NPH and that various degenerative changes in the parenchyma may be responsible for the altered cerebrospinal fluid dynamics characteristic of NPH.

[Anastomosis of the superficial temporal artery to the middle cerebral artery for occlusive disease of the bilateral internal carotid arteries with dementia].

Two cases are reported of occlusive disease of the bilateral internal carotid arteries with dementia in which the anastomosis of the superficial temporal artery to the middle cerebral artery (STA-MCA bypass) resulted in marked improvement in clinical aspects. One patient was a 29-year-old male who complained of transient weakness of the extremities and memory impairment. Computerized tomography (CT) scans showed multiple small infarctions, while cerebral angiography demonstrated findings of Moya-like disease. The cognitive function tests were subnormal and the study of cerebral blood flow (CBF study) showed diffuse low flow in both hemispheres. Based on his clinical symptoms and CBF study, the STA-MCA bypass was performed on both sides in two stages without complications. Postoperatively, his clinical symptoms and cognitive function improved gradually, in accordance with increased CBF in both hemispheres. Six months after the operation, cognitive function tests were within normal limits. Another patient was a 61-year-old hypertensive male who complained of motor weakness, impairment of memory and urinary incontinence. CT scans showed multiple small infarctions, while cerebral angiography revealed occlusion of both internal carotid arteries at the cervical portion. The cognitive function was at the pre-dementia level, and CBF study revealed diffuse low flow in both hemispheres. Based on the clinical symptoms and CBF study, the STA-MCA bypass was performed on both sides in two stages. Postoperatively, clinical symptoms and cognitive function markedly improved. From our results, the diagnosis of vascular dementia, and indications for the use of STA-MCA bypass in this category of patients are discussed.