The value of the cerebrospinal fluid tap test for predicting shunt effectiveness in idiopathic normal pressure hydrocephalus

Table 2 Numbers of patients, sensitivity and specificity for each of variables examined.

	Variables	TP	TN	FP	FN	Sensitivity (%)	Specificity (%)
1	GS-Gait-change	41	16	4	39	51.3	80.0
2	GS-Cogn-change	20	17	3	60	25.0	85.0
3	GS-Urin-change	30	17	3	50	37.5	85.0
4	GS-Total-change	57	13	7	23	71.3	65.0
5	TUG ≥ 10% (sec)¹	26	14	5	50	34.2	73.6
6	MMSE ≥ 3	51	6	14	29	63.8	30.0
7	Tap-any	74	4	16	6	92.5	20.0
8	GS-Total-change, CSFP ≥ 15 cmH₂O²	66	13	7	14	82.5	65.0

Abbreviations: TP: true positives, TN: true negatives, FP: false positives, FN: false negatives (), GS-Gait-change: grading scale gait change 1-2 days after CSF tap, GS-Cogn-change: grading scale cognition change 7 days after tap, GS-Urin-change: grading scale urinary change 7 days after tap, GS-total change: sum of change for all three grading scales, TUG ≥ 10%: ≥ 10% improvement in timed-up -and-go test, MMSE ≥ 3: improvement of 3 or more points on the Mini-Mental State Examination score 7 days after tap, Tap-any: Calculated from improvement in any of the iNPHGS, TUG or MMSE. 1: N = 95 patients, 2: calculated from decision tree analysis.

ISSN: 2045-8118