The changing of cognitive function and the influence of learning effect on the results before and after the CSF tap test in patients with normal pressure hydrocephalus

Abstract

AbstractBackgroundThe CSF tap test evaluation needs repetitive test of walking ability and cognition. Our study aimed to explore the changes of cognitive function and the influence of learning effect on the results in CSF tap test when evaluating the patients with normal pressure hydrocephalus (NPH).MethodCSF tap test was carried out in 134 patients with NPH 2013‐2018 in neurology clinic of Peking Union Medical College Hospital. All patients underwent detailed neuropsychological evaluation (MMSE, MOCA, Trail Making test, Digital symbol, Stroop‐c test) and walking ability (10 meter walking test, up and go test), and head MRI examination. Patients who did not complete the four time point evaluations of CSF tap test due to severe dementia or any other reasons were excluded. Nonparametric test was used to test the difference of z‐scores of executive function (including connection test, number sign and shop‐c test) between the baseline and the four time points after CSF tap test. According to the baseline MMSE scores, the subjects were divided into MMSE > = 26 and MMSE < 26 groups. The changes of z‐scores of three executive function tests were observed in the group.ResultCompared with the baseline, the Z‐score of executive function began to improve at 24 hours and 72 hours, and there was a statistically significant difference (P 0.001 and 0.000, respectively). Within the MMSE > = 26 group, there was a significant improvement in executive function at 24 hours and 72 hours compared with baseline (P <0.05). In the group with MMSE < 26, the executive function Z‐score at 72 hours was significantly improved compared with that at baseline (P = 0.000), while the improvement at 8 hours and 24 hours was not significant.ConclusionIt was found that the executive function of CSF was improved with different evaluation points. According to the classification of MMSE scores, it was found that patients with different cognitive states had different characteristics of executive function curve, which could not be explained by learning effect.