The cerebrospinal fluid drainage test is crucial for evaluating patients with idiopathic normal pressure hydrocephalus (iNPH) before shunt surgery, while traditional methods have low sensitivity. This study aimed to evaluate the improvement of cognitive and gait parameters after external lumbar drainage (ELD) through the application of digital tests and to investigate the predictive value of digital cognitive and gait assessments for shunt outcomes. A total of 70 patients with probable iNPH were enrolled from the West China Hospital of Sichuan University. All patients underwent traditional and digital cognitive and gait assessments at baseline and 3 days after ELD. Thirty-nine patients received lumboperitoneal shunt and were followed up at 3, 6, and 12 months postoperatively using the modified Rankin scale and the Japanese iNPH grading scales. Firth logistic regression models and receiver operating characteristic analysis were used to assess the predictive value of digital tests for shunt response. The performance of the digital tests, including one-back test (P=.01), the Stroop color-word test (P=.009), and gait parameters, exhibited significant improvement 3 days post-ELD. Of the 39 shunted patients, 34 exhibited at least 1-point improvement in modified Rankin scale or iNPH grading scales postshunt at their last follow-up. Greater improvement rates in combined digital neuropsychological and gait tests after ELD were associated with a lower risk of unfavorable shunt outcome (adjusted odds ratio=0.98; P=.03). Combined digital neuropsychological and gait tests outperformed traditional tests in distinguishing shunt responders (area under receiver operating characteristic curves=0.92 vs 0.55, P=.015). Our study shows that digital neuropsychological and gait tests enhance predictive efficacy when compared to traditional testing methods. It could serve as objective evaluation tools for assessing patients with iNPH.