A pilot study of multiple time points and multidomain assessment in cerebrospinal fluid tap test for patients with idiopathic normal pressure hydrocephalus.

Objective: Our study aimed to identify the appropriate evaluation time point and assessment forthe CSF tap test(TT) to predict the shunting responsiveness of patients with idiopathic normal-pressure hydrocephalus (iNPH).

Methods: Eighty-eight inpatients with clinically possible iNPH who underwent CSF TT at multiple time points (baseline, 8 hours, 24 hours, and 72 hours after CSF TT) at Peking Union Medical College Hospital were recruited. The multidomain assessment included the timed up and go test(TUG), 10-meter walking tests, and a brief executive function battery. Performance in multidomain assessment at the indicated time points were compared. The positive response rate and cumulative positive rate of multidomain assessment at multiple time points were calculated. And their corresponding specificity and sensitivity of predicting shunting response were calculated according to the follow-up results after shunting.

Results: The multidomain assessment performance except TUG at 8 hours were significantly improved at each time point after CSF TT compared with baseline (P<0.01). Reduction more than 10% in the 10-meter walking time and number of steps at 24 hours showed the highest specificity (both 85.7%) and sensitivity (37.5% and 46.7%, respectively) for predicting shunting response. Additionally, an improvement of more than 20% in the composite z score at 72 hours showed 100% specificity and 80% sensitivity for predicting shunting response.

Conclusion: Multiple time points and multidomain assessment were helpful to identify more shunting responders. Executive function evaluation might be a candidate tool to increase the effectiveness of CSF TT.