Table 2.
Neuropsychological Measures and Definition of ‘Neurocognitive Deficits’
| Neuropsychological Domain | Test Description | Definition of Neurocognitive Deficit; Adjustment of Norms |
|---|---|---|
| Attention | The Continuous Performance Test (identical pairs version; CPT-IP) 34 provided a measure of sustained attention. The signal detection parameter d' was calculated across 300 trials. | CPT-IP—d' (more than 1 SD below mean); norms unadjusted for age. 35 |
| Memory | ||
| Verbal memory | The Auditory Verbal Learning Test (AVLT) 36 provided a verbal memory measure for immediate and delayed recall after one to 5 learning trials of word lists. | AVLT immediate recall—no. correct after 1st trial (PR < 16); norms adjusted for age. 37 AVLT trials 1–5—sum no. correct (PR < 16); norms adjusted for age. 37 AVLT delayed recall—no. correct after 30min (PR < 16); norms adjusted for age. 37 |
| Visual memory | A measure of visual memory was provided by the Rey-Osterrieth Complex Figure Test (ROFT). 38 The delayed recall performance was scored according to L.B. Taylor’s criteria. | ROFT—delayed recall (more than 1 SD below mean); norms adjusted for age. 39(p827) |
| Working memory | ||
| Spatial working memory | During each trial of a computerized version of the Subject Ordered Pointing Task (SOPT) 40 subjects had to point to 1 of 12 objects, and the relative positions of the objects varied randomly across trials. Across 3 sessions of 12 trials the number of errors (pointing to an object already chosen on a previous trial) was calculated. | SOPT—no. errors (more than 1 SD below mean); norms adjusted for age. 39(p475) |
| Executive functions | ||
| Set shifting and problem solving | The percentage of perseverative and nonperseverative errors made in the Wisconsin Card Sorting Test (WCST) 41 provided a measure of set shifting and problem solving. | WCST—% errors (T < 40); norms adjusted for age. 41 |
| Verbal executive functions | Verbal executive functions were measured by a verbal fluency task (a lexical and a semantic category task). 42 For lexical verbal fluency as many words as possible beginning with a S and for semantic verbal fluency as many animal names as possible had to be produced within 1min. | Lexical verbal fluency—no. correct (PR < 16); norms adjusted for age. 42 Semantic verbal fluency—no. correct (PR < 16); norms adjusted for age. 42 |
| Processing speed | The digit symbol test (DST) 43 and trail-making test (TMT) A and B 44 provided measures for the speed of visual information-processing and visuomotor coordination. | DST—no. correct (T < 40); norms adjusted for age. 43 TMT A and B—time in s (more than 1 SD below mean); norms adjusted for age. 39(p659) Ratio TMT B/A (more than 1 SD below mean); norms adjusted for age. 39(p663) |
Notes: PR, percentile; M, mean. All neuropsychological measures were already described in an earlier publication of the same sample.33(p44–45)