Table 3. Memory function depending on age group.

Age	≤ 69 years	70–79 years	≥ 80 years	P-value
Values are expressed as means ± SD for absolute data and as % and SD for relative values. DST: digit span test; WL-A: wordlist repeat; WL-W: wordlist recall.
Preoperative memory function
WL-W-task, n = 146	n = 10	n = 46	n = 90
Repeated words	16.10 ± 2.38	15.35 ± 3.50	13.17 ± 3.75	< 0.001
Repeated words z-value	–1.73 ± 1.10	–1.48 ± 1.15	–1.46 ± 1.11	0.769
WL-A-task, n = 145	n = 10	n = 46	n = 89
Repeated words	3.20 ± 1.48	2.65 ± 2.30	1.79 ± 2.06	0.023
Repeated words z-value	-2.48 ± 1.01	-2.20 ± 1.21	-2.00 ± 1.09	0.351
DST, n = 146	n = 10	n = 46	n = 90
Digit span	6.00 ± 1.25	5.39 ± 1.06	5.40 ± 0.95	0.191
Pre-post-operative comparison
WL-W, n = 112	n = 5	n = 39	n = 68
Change of mean repeated words (t1-t0)	2.00 ± 3.08	2.56 ± 2.81	1.90 ± 3.46	0.590
Changes in %	13.47% ± 19.59%	16.79% ± 19.67%	19.26% ± 32.82%	0.849
WL-A, n = 111	n = 5	n = 39	n = 67
Change of mean repeated words (t1-t0)	0.40 ± 2.30	0.74 ± 1.67	0.94 ± 1.99	0.758
Changes in %	70% ± 186.58%	50.62% ± 121.83%	83.63% ± 166.09%	0.565
DST, n = 111	n = 5	n = 40	n = 68
Change of mean repeated numbers (t1-t0)	–0.20	–0.05	0.06	0.748
Changes in %	–2.5 ± 13.4	0.46 ± 18.37	1.51 ± 15.46	0.846