Preoperative cognitive impairment (preCI) and postoperative cognitive dysfunction (POCD)
POCD, Verbal Recognition Memory
A neuropsychological test battery comprising four computerized (CANTAB, Cambridge Cognition Ltd., UK. Paired Associates Learning (PAL), Verbal Recognition Memory (VRM), Spatial Span Length (SSP) and Simple Reaction Time (SRT)) and two non-computerized cognitive tests (Trail-Making-Test (TMT) in a pen-and-paper format and the manual Grooved Pegboard Test (GPT)) was used for the cognitive assessment (Table Neuropsychological tests.For more information, please see Lammers et al.Neuropsychological test results (baseline).14.0 (4.2)N = 2393.9 (1.8)N = 326.7 (1.8)N = 2421.8 (1.9)N = 20819.1 (2.4)N = 2722.4 (1.8)N = 184.9 (0.9)N = 24193.1 (24.7)N = 230133.3 (43.7)N = 3293.5 (19.9)N = 22309.0 (89.6)N = 242112.3 (39.1)N = 222174.5 (73.0)N = 24125.6 (64.0)N = 22The table displays mean and standard deviation in parentheses for preoperative cognitive test results. In case of missing data, the N of patients with available data was added to items with cases of missing data.Neuropsychological test results (post).15.5 (3.9)N = 16410.6 (4.8)N = 1810.7 (4.7)N = 246.4 (1.7)N = 1674.5 (1.6)N = 1921.8 (2.0)N = 16419.3 (2.6)N = 1720.0 (2.6)N = 245.0 (0.8)N = 1664.6 (1.1)N = 1888.0 (16.7)N = 164116.1 (25.0)N = 18309.4 (77.0)N = 167347.4 (94.9)N = 19102.7 (35.0)N = 162118.7 (30.3)N = 11123.3 (48.5)N = 22The table displays mean and standard deviation in parentheses for postoperative cognitive test results at follow-up. In case of missing data, the N of patients with available data was added to items with cases of missing data.POCD was defined as a dichotomous variable based on an algorithm adjusting the difference in neuropsychological test scores between pre-surgery and a 3-month postsurgical assessment for natural variability and learning effects based on cognitive testing performed in a non-surgical control group a. For calculations the following seven cognitive test parameters were usedPaired Associates Learning—memory score calculated for the first trial.Verbal Recognition Memory—number of correctly remembered words in ‘Free recall’.Verbal recognition memory—number of correct and incorrect responses in ‘Delayed Recognition’.Spatial span—spatial length (longest correct recognition sequence of squares appearing in different order).Grooved pegboard—time (s) needed for the insertion of certain amount of pegs into differently-shaped holes on a board using the dominant hand (log-transformed and reversed).Simple reaction time (s)—the mean of correct trials (log-transformed and reversed).Trail-making test B (s)—(log-transformed and reversed).To define relevant cognitive change and for dichotomization the Reliable Change Index model as published by Rasmussen et al.