Tap Test Can Predict Cognitive Improvement in Patients With iNPH—Results From the Multicenter Prospective Studies SINPHONI-1 and –2

Abstract

Background: We analyzed the predictive value of the tap test (TT) on the outcome of cerebrospinal fluid (CSF) shunting in patients with idiopathic normal pressure hydrocephalus (iNPH) and cognitive impairment up to 12 months postoperatively.Methods: We analyzed the data of two prospective multicenter studies on ventriculoperitoneal shunt (VPS) and lumboperitoneal shunt (LPS) use in iNPH patients. We selected patients with Mini-Mental State Examination (MMSE) scores ≤ 26 points as study subjects. We used a multivariate logistic regression model to obtain the optimal threshold of MMSE scores after TT to predict the score improvement at 12 months following shunting and that helped to control for confounding factors such as age and MMSE scores before TT. We used logistic regression models to identify variables with age-adjusted odds ratio (A-OR) and multivariate-adjusted OR (M-OR).Results: For an improvement of ≥3 points in the MMSE score cutoff 7 days following TT in VPS and LPS cohort studies, the MMSE scores improved by 6 points after 12 months. The VPS cohort had sensitivity, specificity, and area under the curve (AUC) of 69.2, 73.7, and 0.771%, respectively; however, for the LPS cohort, they were 86.2, 90.9, and 0.906%, respectively. For MMSE scores that improved by ≥3 points in patients after the TT, the possibility of an improvement by 6 points at 12 months following CSF shunt had A-OR 7.77 and M-OR 6.3 times for the VPS, and A-OR 62.3 and M-OR 59.6 times for the LPS cohort.Conclusion: CSF shunting contributes to improved cognitive function in iNPH patients. Furthermore, MMSE score evaluation at the TT can sensitively predict improvement in postoperative MMSE scores following LPS intervention.Clinical Trial Registration: SINPHONI-1 (ClinicalTrials.gov, no. NCT00221091), first posted: September 22, 2005.SINPHONI-2 [University Hospital Medical Information Network (UMIN) Clinical Trials no. UMIN000002730], the posted: February 1, 2010.

Predictive Ability of Frontal Assessment Battery for Cognitive Improvement After Shunt Surgery in Individuals With Idiopathic Normal Pressure Hydrocephalus

“…However, contrary to our results, Nakajima et al (2021) reported that postoperative improvement in MMSE scores was predictable based on MMSE score changes after CSF tapping. Likewise, Kazui et al (2013) reported that baseline MMSE scores were significantly associated with postoperative MMSE improvement.…”

“…Postoperative MMSE was performed 12 months after surgery in the two studies; in our study, the average number of days from surgery to postoperative MMSE was 42. Furthermore, in Nakajima and colleagues’ (2021) study, the period from CSF tapping to the MMSE was 1 week, whereas in ours, it was 24–48 hours. Another study on longitudinal change after CSF tapping showed that MMSE scores recovered more slowly than FAB scores (Matsuoka et al, 2018).…”

“…Previous studies have suggested that postoperative cognitive improvement can be predicted by score changes in the Mini-Mental State Examination (MMSE; Folstein et al, 1975) and the Rey Auditory Verbal Learning Test-L (Gavett and Horwitz, 2012; Rey, 1958) from before to after temporal CSF drainage (McGovern et al, 2019; Nakajima et al, 2021). Compared with cognitive impairment in Alzheimer disease, which predominantly affects the memory functions of general memory and delayed recall, cognitive impairment in iNPH predominantly affects the frontal lobe functions of verbal fluency, attention, psychomotor speed, and executive function (Miyoshi et al, 2005; Ogino et al, 2006).…”

Relationship between disproportionately enlarged subarachnoid-space hydrocephalus and white matter tract integrity in normal pressure hydrocephalus

“…Based on the criterion of at least 10% improvement in gait velocity in the timed up and go evaluation 15 , 70% (low-DESH group) and 62.5% (high-DESH group) patients showed improvement, respectively. Improvements of 3 or more points in cognitive function assessed by Mini-Mental State Examination (MMSE) before and after the CSF tap test were observed in approximately 20 and 18.8%, respectively 16 . Shunt surgery was performed in only 8 of 33 patients, all but one of whom were in the high-DESH group.…”

“…A responder was defined as a patient who showed an improvement of 10% or more in walking speed 6 h and 24 h after the CSF tap test, based on the results of the timed up and go evaluation performed at the time of the tap test 15 . For cognitive function, we checked the change in MMSE score before and after the CSF tap test to determine if the score improved by 3 points or more 16 . We investigated whether a ventriculoperitoneal shunt operation was performed and checked the change in symptoms before and after the operation through the electronic medical records.…”