A new functional test in the diagnostic evaluation of neurogenic intermittent claudication.

A new functional test using downhill walking is described and evaluated in relation to the myelographical examination in 23 consecutive patients with neurogenic intermittent claudication. Discomfort and changes of the neurological status, emerging during the walk, were accepted as test results. They were noted in a decision matrix and the positive and the negative predictive values (PPV and NPV, respectively) calculated. The PPV of any symptom or any deterioration of the neurological status, resulting from this test as signs of a myelographical abnormality, was calculated to be 86 and 89 per cent, respectively, the corresponding NPV's being 50 and 40 per cent, respectively. The NPV of these parameters as signs of a myelographically verified lumbar spinal stenosis was calculated to be 100 per cent, the corresponding PPV's being 38 and 44 per cent, respectively. The development of "symptom-march" or of bilateral neurological signs during the walk was found to be of approximately the same diagnostical value. We conclude, that this function test may serve as a screening procedure in patients complaining of neurogenic intermittent claudication.