Neal F. Kassell

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BACKGROUND The management of unruptured intracranial aneurysms is controversial. Investigators from the International Study of Unruptured Intracranial Aneurysms aimed to assess the natural history of unruptured intracranial aneurysms and to measure the risk associated with their repair. METHODS Centres in the USA, Canada, and Europe enrolled patients for(More)
This paper reports a mechanism that learns how to use a menu structure by exploration. The model, called Ayn, starts without any knowledge of the menus but when given a goal, explores and tries out options until the goal has been achieved. During this process it constructs a long-term, recognition-oriented, memory of its behavior so that on future occasions(More)
We present a survey of design issues for developing effective free-space three-dimensional (3D) user interfaces. Our survey is based upon previous work in 3D interaction, our experience in developing free-space interfaces, and our informal observations of test users. We illustrate our design issues using examples drawn from instances of 3D interfaces. For(More)
Cerebral vasospasm following aneurysmal subarachnoid hemorrhage is one of the most important causes of cerebral ischemia, and is the leading cause of death and disability after aneurysm rupture. There are two definitions of cerebral vasospasm: angiographic and clinical. Care must be exercised to be certain that it is clear which entity is being addressed.(More)
We report results from a formal user study of interactive 3D rotation using the mouse-driven Virtual Sphere and Arcball techniques, as well as multidimensional input techniques based on magnetic orientation sensors. Multidimensional input is often assumed to allow users to work quickly, but at the cost of precision, due to the instability of the hand moving(More)
The International Cooperative Study on the Timing of Aneurysm Surgery evaluated the results of surgical and medical management in 3521 patients between December, 1980, and July, 1983. At admission, 75% of patients were in good neurological condition and surgery was performed in 83%. At the 6-month evaluation, 26% of the patients had died and 58% exhibited a(More)
BACKGROUND AND PURPOSE This randomized, double-blind, placebo-controlled, dose-finding study assessed efficacy and safety of 1, 5, and 15 mg/h intravenous clazosentan, an endothelin receptor antagonist, in preventing vasospasm after aneurysmal subarachnoid hemorrhage. METHODS Patients (n=413) were randomized to placebo or clazosentan beginning within 56(More)
OBJECTIVES This report examines the frequency, type, and prognostic factors of medical (nonneurologic) complications after subarachnoid hemorrhage in a large, prospective study. The influences of contemporary neurosurgical, neurological, and critical care practice on mortality and morbidity rates after aneurysmal subarachnoid hemorrhage are evaluated. (More)
Of five patients with damage to the basal forebrain, four had lesions secondary to rupture of anterior cerebral or anterior communicating artery aneurysms, and one to the resection of an arteriovenous malformation. Computed tomographic scans and intraoperative reports confirmed damage to basal forebrain regions, which include septal nuclei, nucleus(More)