Dear Sunil:

In our practice, diagnosis of shunt-dependent NPH rests on the (partial) presence of the Hakim-Adams sydrome, the disproportionate enlargement of the ventricles as compared to the external subarachnoid space, a callosal angle below 63°, the presence of transependymal CSF diapedesis and a positive response to a modified lumbar tap test which we usually achieve by continous lumbar drainage over 72 hours. Please note that while a positive clinical response following a standard tap test by lumbar puncture is highly predictive for clinical improvement after shunting, a negative clinical response provides only low predictive accuracy, meaning that many patients will still improve after shunting despite a lack of improvement following a standard tap test. Therefore, I would consider clinical improvement after continous lumbar drainage as the single best predictor for successful shunting if the diagnosis of NPH was sufficiently established as outlined above.

Kind regards,

Marc

Thank you sir,

There has also been recent study of role of dynamic gait index in predicting role of shunt in NPH

I agree with Halatsch's opinions. When a positive results after a lumbar puncture, the improvement would be significant. When negative results after LP, the improvement rate is low, esp in elder people..  

Dr. Sunil your question is clarifying differences of opinions and practices between different neurosurgeons. We have here an important chance to compare two answers. Respected Dr. Halatsch stresses the importance of not missing a patient by depending on 3 day drainage test (the golden test). Respected Dr. Pro-Chou Liliang answer prefers avoiding a risk of over drainage in the elderly and he is depending on LP. Even for all those who are doing 3 days drainage test; you will find some who will withdraw 50 ml per day and others who are withdrawing 150 - 200 ml per day.