The Dutch Normal-Pressure Hydrocephalus study - How to select patients forshunting? An analysis of four diagnostic criteria

BACKGROUND Comparison of the predictive value of four "diagnostic tests" for the outco me of shunting in patients with normal-pressure hydrocephalus (NPH). METHODS Ninety-five NPH patients who received shunts were followed for 1 year. Gait disturbance and dementia were quantified by an NPH scale and handicap by a modified Rankin scale. Primary outcome measures were differences between t he preoperative and last scores on both the NPH scale and the modified Rank in scale. Clinical and computed tomographic (CT) findings typical of NPH, a bsence of cerebrovascular disease, and a resistance to outflow of cerebrosp inal fluid (CSF) greater than or equal to 18 mmHg/ml/ minute were designate d as a positive test outcome; clinical and CT findings compatible with NPH, presence of cerebrovascular disease, and an outflow resistance < 18 mmHg/m l/minute as a negative test outcome. RESULTS For each of the four tests the percentage of patients classified as improve d was significantly greater for those with positive than with negative test results. Measurement of CSF outflow resistance was the only significant pr ognostic factor for the improvement ratio in NPH scale and CT in the modifi ed Rankin scale according to multivariate logistic regression analysis. The accurate predictive value of the combination of typical clinical and CT fi ndings was 0.65, that of the positive test results of outflow resistance, c linical and CT findings was 0.74. CONCLUSION The best strategy is to shunt NPH patients if their outflow resistance is g reater than or equal to 18 mmHg/ml/minute or, when the outflow resistance i s lower, if their clinical as well as their CT findings are typical of NPH. (C) 2000 by Elsevier Science Inc.