Abstract

As part of the NEURONORMA project, we provide age- and education-adjusted norms for the Stroop color-word interference test (SCWT)-Golden version and the Tower of London-Drexel University version (TOLDX). The sample consists of 344 and 347 participants, respectively, who are cognitively normal, community dwelling, and ranging in age from 50 to 90 years. Tables are provided to convert raw scores to age-adjusted scaled scores. These were further converted into education-adjusted scaled scores by applying regression-based adjustments. Demographic variables, age, and education significantly affect scores of the SWCT and TOLDX, sex, however, was found to be unrelated to performance in this sample. The normative data presented here were obtained from the same study sample as all the other NEURONORMA tests. In addition, the same statistical procedures for data analyses were applied. These co-normed data allow clinicians to compare scores from one test with all tests.

Introduction

The Spanish multicenter normative studies (NEURONORMA) project (Peña-Casanova et al., 2009) attempts to provide useful norms for people aged over 49 years for commonly used neuropsychological tests. In this paper, we provide normative data for the Stroop color-word interference test (SCWT; Golden, 1978; Stroop, 1935) and the Tower of London-Drexel University version (TOLDX; Culbertson & Zillmer, 1998a).

Stroop Color-Word Interference Test

This test is a measure of cognitive flexibility, selective attention, cognitive inhibition, and information processing speed (Bryan & Luszcz, 2000; Rosselli et al., 2002; Van der Elst, Van Boxtel, Van Breukelen, & Jolles, 2006). Data from studies with fMRI strongly suggest that the inferior frontal, dorsolateral prefrontal and anterior cingulate cortices are involved in tasks such as Stroop test in which maintaining attentional control over conflicting responses is needed (Egner & Hirsch, 2005; Harrison et al., 2005; Peterson et al., 1999). A number of versions of the SCWT have been developed (for reviews see Lezak, Howieson, & Loring, 2004; Mitrushina, Boone, Razani, & D’Elia, 2005; Steinberg, Bieliauskas, Smith, & Ivnik, 2005 [selective review of studies that address the effects of subject variables]; Strauss, Sherman, & Spreen, 2006). The tests are based on the fact that it takes a longer time to call out the color names of colored forms than to read words, and even longer to name the color of the ink in which a color name is printed when the print ink is a color different from the color name (Dyer, 1973). This decrease in color-naming speed is called the color-word interference effect or Stroop effect (Lezak et al., 2004; Strauss et al., 2006). Poor performance on the SCWT has been found in a wide variety of patient groups. A review of this topic is, however, beyond the objective of this paper (for reviews see Lezak et al., 2004; Mitrushina et al., 2005; Strauss et al., 2006). Cognitive control in the SCWT is implemented by medial and lateral prefrontal cortices that bias processes in regions that have been involved in high-level perceptual and motor processes (Egner & Hirsch, 2005), and the task is consistent with a network model of SCWT performance (Peterson et al., 1999).

Demographic effects such as age, education, and sex have been frequently associated with SCWT scores. Age accounts for a significant amount of variability in the interference scores (the Golden version, Mitrushina et al., 2005). Aging produces a slowing in color naming and an increase in the interference effect (Bryan & Luszcz, 2000; Cohn, Dustman, & Bradford, 1984; Graf, Uttl, & Tuokko, 1995; Lucas et al., 2005; Moering, Schinka, Mortimer, & Graves, 2004; Uttl & Graf, 1997; Van der Elst et al., 2006). A recent study suggests that the age difference in Stroop interference is partially attributable to general slowing, but is also due to age-related changes in task-specific processes such as inhibitory control (Bugg, DeLosh, Davalos, & Davis, 2007; Connor, Franzen, & Sharp, 1988; Troyer, Leach, & Strauss, 2006). Age and error scores on the interference trial are positively correlated, indicating decreased accuracy with age (Troyer et al., 2006; Van der Elst et al., 2006).

Gender differences on the SCWT performance have been studied. For studies, sex has only a minor influence on Stroop test performance at any age (MacLeod, 1991), and for others those differences are simply absent (Anstey, Matters, Brown, & Lord, 2000; Ivnik et al., 1996) or minimal (Lucas et al., 2005). However, several investigators found interesting sex differences on the performance of the SCWT, with female advantage over men (Moering et al., 2004; Strickland, D'Elia, James, & Stein, 1997; Van der Elst et al., 2006).

Education has some effect on the SCWT score in adults (Anstey et al., 2000; Ivnik et al., 1996; Lucas et al., 2005; Steinberg et al., 2005; Van der Elst et al., 2006). In addition to previous data (Strickland et al., 1997), it was found that in Afro-American education had a strong effect on SCWT scores, accounting for 8%–26% of the variance, followed by sex and age (Moering et al., 2004). However, in another study on Afro-American age and education each accounted for about 8%–9% of the variance in performance on the interference trial (Lucas et al., 2005).

There are a number of studies that provide normative data for the different languages that the SCWT has been adapted to (Lezak et al., 2004; Mitrushina et al., 2005; Strauss et al., 2006). Specifically, there are some studies that provide normative data in Spanish language. Artiola, Hermosillo, Heaton, and Pardee (1999) studied Golden's version of the SCWT in a Spanish sample, aged from 18 to 65+ years, of 250 residents from the Madrid region (Spain) and in 185 Spanish speakers from the U.S.-Mexico border region. Rosselli and colleagues (2002) obtained normative data on 40 English monolinguals, 71 Spanish–English bilinguals, and 11 Spanish monolinguals in south Florida. Lopez, Salazar, Villaseñor, Saucedo, and Peña (2003 [cited in Mitrushina et al., 2005]) studied the effects of demographic variables on a series of neuropsychological tests including the SCWT (the Golden version). The total sample included 115 monolingual Latino men. Norms in Spanish for children were provided by Armengol (2002).

Tower of London

This test was originally developed by Shallice (1982) to assess higher-order problem solving and, specifically, executive planning abilities in subjects with damage to frontal lobes (for antecedents and modifications of the TOL see Culbertson & Zillmer, 2001, and Lezak et al., 2004). The test consists of two boards with pegs and several beads with different colors (green, red, and blue). The subject must look ahead to determine the order and the number of moves necessary to rearrange the beads from their initial position to a new set of predetermined positions on one or more of the pegs. The constraints are: (a) only one bead may me moved at a time; (b) each bead may be moved only from peg to peg; and (c) only a specified number of beads may be left on each peg at a time (Lezak et al., 2004; Shallice, 1982). Levels of difficulty of the TOL items depend on the complexity of subgoals required to achieve the predetermined position. There are several variants of the test (for a review see Lezak et al., 2004), including a version published by the Drexel University (TOLDX) (Culbertson & Zillmer, 1998a, 1998b, 2001).

This test is somewhat controversial because, although is used to measure executive planning abilities (Sullivan et al., 2009), other factors are also important for successful performance, such as response inhibition, visuospatial memory, and working memory (Carlin et al., 2000; Phillips, Wynn, Gilhoody, Della Sala, & Logie, 1999; Zook, Davalos, DeLosh, & Davis, 2004). Moreover, a number of issues remain unaddressed in the literature, such as the problem structure, or problem space of the task, the impact of the modifications of the original, the variety of performance measures that can be derived (Berg & Byrd, 2002), and the impact of instructions, cuing, and learning processes as determinants of TOL performance (Unterrainer, Rahm, Leonhart, Ruff, & Halsband, 2003). In fact, neuroimaging studies show that using the TOL during planning activities a wide series of brain structures are activated, and in a similar manner to the SCWT, the TOL task is consistent with a network of areas which are not “simply” related to the prefrontal cortex. These include the dorsolateral prefrontal cortex, the anterior part of the cingulate cortex, the cuneus, the precuneus, and the supramarginal and angular gyri in the parietal lobe (Boghi et al., 2006; Lazeron et al., 2000; Newman, Carpenter, Varna, & Just, 2003).

Few studies have reported normative data and the demographic factors influence on the performance of the TOL test. Concerning age, the original normative sample of the TOLDX recruited in three sites in the USA and four in Canada presented only age differences for the oldest group (+60 years), which were specifically related to the number of errors, number of total movements, and number of total time violation (Culbertson & Zillmer, 2001). However, age effect in TOL performance has not been clearly supported by other investigations. In fact, Bryan and Luszcz (2000) only found a small but significant negative correlation between age and performance on the TOL test, and Zook, Welsh, and Ewing (2006) concluded that the age differences in TOL-R (TOL-revised, Schnirman, Welsh, & Retzlaff, 1998) were eliminated after adjusting for individual differences in reasoning performance.

Few data on the influence of education or sex on the TOL performance have been provided. Some authors conclude that this task is not significantly influenced either by education (Zook et al., 2006) or gender (Culbertson & Zillmer, 2001).

At present, no normative data in the Spanish population for any version of TOL tasks have been published. Our study is the first attempt to provide standards for the performance on the Drexel University version of TOL in a Spanish sample.

The normative data of SCWT and TOLDX presented in this paper are a part of a co-norming project that includes a wide range of neuropsychological tests. Co-norming clearly facilitates accuracy in cognitive pattern analysis in clinical settings.

Materials and Methods

Research Participants

We offer here a summary of the socio-demographic and participant characteristics of the entire NEURONORMA sample which have been reported in detail in a previous paper (Peña-Casanova et al., 2009). This is an observational cross-sectional study performed in nine services of neurology in Spain. Ethical approval for the study was granted by the Research Ethics Committee of the Municipal Institute of Medical Care of Barcelona. The ethnic background of all participants was Caucasian, and all were Spanish speakers.

Entry criteria included cognitively normal, consecutive individuals according to a series of inclusion and exclusion criteria. Cognitive normalcy was validated via informants, an ADL scale (the Interview for Deterioration of Daily living in Dementia; Böhm et al., 1998 [Spanish validated version]; Teunisse, Derix, & Crever, 1991), and a cognitive screening test, the mini-mental state examination (Blesa et al., 2001 [Spanish validated version]; Folstein, Folstein, & McHugh, 1975). As in the MOANS projects, volunteers did not need to be completely medically healthy to participate (Pedraza et al., 2005). Subjects with active, chronic medical, psychiatric, or neurological conditions or with physical disabilities were included if the researcher judged that the condition was correctly controlled or resolved and did not cause cognitive impairment. The same criterion was applied in the case of use of psychoactive medications. A total of 344 subjects were studied for the SCWT and 347 for the TOLDX. Basic demographic information concerning both tests is presented in Table 1.

Table 1.

Sample size by demographics and test

 SCWT
 
TOLDX
 
 N Percent N Percent 
Age group 
 50–56 75 21.80 76 21.90 
 57–59 51 14.83 51 14.70 
 60–62 34 9.88 34 9.80 
 63–65 18 5.23 18 5.19 
 66–68 25 7.27 25 7.20 
 69–71 47 13.66 48 13.83 
 72–74 32 9.30 32 9.22 
 75–77 30 8.72 31 8.93 
 78–80 20 5.81 21 6.05 
 >80 12 3.49 11 3.17 
Education (years) 
 ≤5 73 21.22 71 20.46 
 6–7 24 6.98 25 7.20 
 8–9 66 19.19 66 19.02 
 10–11 40 11.63 39 11.24 
 12–13 36 10.47 36 10.37 
 14–15 32 9.30 34 9.80 
 ≥16 73 21.22 76 21.90 
Gender 
 Men 134 38.95 140 40.35 
 Women 210 61.05 207 59.65 
Total sample 344  347  
 SCWT
 
TOLDX
 
 N Percent N Percent 
Age group 
 50–56 75 21.80 76 21.90 
 57–59 51 14.83 51 14.70 
 60–62 34 9.88 34 9.80 
 63–65 18 5.23 18 5.19 
 66–68 25 7.27 25 7.20 
 69–71 47 13.66 48 13.83 
 72–74 32 9.30 32 9.22 
 75–77 30 8.72 31 8.93 
 78–80 20 5.81 21 6.05 
 >80 12 3.49 11 3.17 
Education (years) 
 ≤5 73 21.22 71 20.46 
 6–7 24 6.98 25 7.20 
 8–9 66 19.19 66 19.02 
 10–11 40 11.63 39 11.24 
 12–13 36 10.47 36 10.37 
 14–15 32 9.30 34 9.80 
 ≥16 73 21.22 76 21.90 
Gender 
 Men 134 38.95 140 40.35 
 Women 210 61.05 207 59.65 
Total sample 344  347  

Note: SCWT = Stroop color-word interference test; TOLDX = Tower of London-Drexel University version.

Neuropsychological Measures

The neuropsychological measures were administered as part of a larger test battery, the NEURONORMA battery (Peña-Casanova et al., 2009). Tests were administered and scored by neuropsychologists specifically trained for this project.

Stroop Color-Word Interference Test

Golden's version of the SCWT (Golden, 1975) was used in this project. This version consists of a word page (p. 1) with 100 color words printed in black ink, a color page (p. 2) with 100 “Xs” printed in color (red, green, and blue), and a color-word page (p. 3) with 100 words from the first page printed in colors from the second page (the color and the word do not match). Subjects are asked to read down the columns starting with the top word in the leftmost column. After 45 s, the item last named on each stimulus card is noted. The test produces three scores: The word reading (W) score consists of the number of items completed on p. 1; the color-naming (C) score is made up of the number of items completed on p. 2; and the color-word (CW) score is made up of the number or items completed on p. 3. Standard administration procedures were followed as indicated in the test manual (Golden, 1978).

Tower of London-Drexel University Version

Although similar to the Tower of London originally developed by Shallice (1982), the Drexel University version (Culbertson & Zillmer, 2000) presents a number of modifications in administration and test scoring. This test uses two boards with three pegs (“tower boards”): On one the examiner places three colored wooden balls (blue, green, and red) in a goal position, and on the other there are three colored wooden balls that the subject must rearrange from a standard start position to the examiner's model. Ten problems are given in the order of increasing difficulty. Two minutes are allowed for each trial.

The original boards were substituted by larger ones previously developed in the context of this project. The test was administered and scored following the manual.

In this project, five different scores were obtained from both number or moves, and also successful completion and timing aspects. Here follows a brief extract of the scoring method from the test manual (for details see Culbertson & Zillmer, 2001).

  • Total correct score: The correct score is equal to the number of test problems solved with the minimum number of moves (in fact without extra moves). A total correct score of 10 is the upper limit.

  • Total moves score: The total moves score constitutes the primary score and is based on the number of moves the examinee executes in solving a test problem. A move has occurred when a ball is completely removed from a peg and then is either placed on another peg or replaced on the same peg. The minimum number of solution moves for each task problem is subtracted from the examinee's actual move count to determine the move score. The total moves score is the sum of the move scores for each of the individual test problems. The total moves score can range from 0 to 145.

    Three time scores are calculated for each configuration: First, the initiation time score, defined as the time from the presentation of a test problem by the examiner to the initiation of the first problem-solving move (time limit cannot exceed 120 s for each configuration). Second, the execution time score, representing the time from the initiation of the first move to the completion or discontinuation of problem solving (maximum time allowed for each configuration is 120 s). Third, the problem-solving time score, defined as the interval from the presentation of a test problem to its completion or discontinuation by the participant (i.e., problem-solving time = initiation time + execution time). Considering that the time limit for each configuration is 2 min, the maximum time entry for any problem is 120 s. From the time scores of each problem, three total derived variables are obtained.

  • Total initiation time score, defined as the sum of the initiation time scores of the 10 test problems.

  • Total execution time score, defined as the sum of the execution time scores of the 10 problems.

  • Total problem-solving time score, defined as the sum of the problem-solving time scores of the 10 problems.

Statistical Analysis

Considering that the ability to compare all co-normed test scores directly with each other facilitates clinical interpretation of neuropsychological test profiles, a uniform normative procedure was applied to all measures as in the MOANS studies (Ivnik et al., 1992, 1996; Lucas et al., 2005).

The overlapping interval strategy (Pauker, 1988) was adopted to maximize the number of subjects contributing to the normative distribution at each mid-point age interval. Effects of age, sex, and education on raw subtest scores were studied using coefficients of correlation (r) and determination (r2; Lucas et al., 2005). The frequency distribution of the raw scores (RS) was converted into age-adjusted scaled scores, NSSA (NEURONORMA scaled score-age adjusted), following the methodology described by Ivnik and coleagues (1992). For each age range, a cumulative frequency distribution of the RS was generated. Raw scores were assigned percentile ranks in function of their place within a distribution. Subsequently, percentile ranks were converted to scaled scores (from 2 to 18) based on percentile ranges. This transformation of RS to NSSA produced a normalized distribution (mean = 10; SD = 3) on which linear regressions could be applied. Years of education were modeled using the following equation: NSSA = k + (β × Education). The resulting equations were used to calculate age- and education-adjusted NEURONORMA scaled scores (NSSA&E) for each variable. The regression coefficient (β) from this analysis was used as the basis for education adjustments. A linear regression was employed to derive age- and education-adjusted scaled scores. The following formula outlined by Mungas, Marshall, Weldon, Haan, and Reed (1996) was employed: NSSA&E = NSSA – (β × [Education – 12]). Following the method described by Mungas and colleagues (1996), the obtained NSSA score was adjusted by the difference between the predicted scores based on the subject's actual education and the predicted score given 12 years of education. The obtained value was truncated to the next lower integer (e.g., 10.75 would be truncated to 10).

Results

Age distribution of the sample made it possible to calculate norms for 10 mid-point age groups. Sample sizes resulting from mid-point age intervals are presented in normative tables.

Correlations (Pearson's, r) and shared variance (determination coefficient, r2) of SCWT and TOLDX scores with age (years), education (years), and sex are presented in Table 2.

Table 2.

Correlations (r) and shared variances (r2) of raw scores with age, year of education, and sex

Measure Age (years)
 
Education (years)
 
Sex
 
r r2 r r2 r r2 
SCWT 
 Part A: Word −0.3278 0.10746 0.52403 0.27461 −0.035 0.00122 
 Part B: Color −0.4785 0.22892 0.47209 0.22287 0.06718 0.00451 
 Part C: Interference −0.4662 0.21732 0.41615 0.17318 0.07343 0.00539 
TOLDX 
 Total moves score 0.1657 0.02746 −0.333 0.1109 0.14156 0.02004 
 Total correct score −0.1137 0.01292 0.32774 0.10741 −0.143 0.02046 
 Total initiation time score 0.09987 0.00997 0.08086 0.00654 −0.1566 0.02453 
 Total execution time score 0.34353 0.11801 −0.3261 0.10632 0.12278 0.01507 
 Total problem-solving time score 0.34317 0.11777 −0.2707 0.07326 0.06236 0.00389 
Measure Age (years)
 
Education (years)
 
Sex
 
r r2 r r2 r r2 
SCWT 
 Part A: Word −0.3278 0.10746 0.52403 0.27461 −0.035 0.00122 
 Part B: Color −0.4785 0.22892 0.47209 0.22287 0.06718 0.00451 
 Part C: Interference −0.4662 0.21732 0.41615 0.17318 0.07343 0.00539 
TOLDX 
 Total moves score 0.1657 0.02746 −0.333 0.1109 0.14156 0.02004 
 Total correct score −0.1137 0.01292 0.32774 0.10741 −0.143 0.02046 
 Total initiation time score 0.09987 0.00997 0.08086 0.00654 −0.1566 0.02453 
 Total execution time score 0.34353 0.11801 −0.3261 0.10632 0.12278 0.01507 
 Total problem-solving time score 0.34317 0.11777 −0.2707 0.07326 0.06236 0.00389 

Note: SCWT = Stroop color-word interference test; TOLDX = Tower of London-Drexel University version.

Age and education accounted significantly for the RS variance of the SWCT (age: 10%–22%; education: 17%–27%). Education effect is specifically reflected in the reading part of the test (27% of the shared variance). Sex differences were not observed, indicating no need to control this demographic variable.

Education accounted significantly for the RS variance of TOLDX variables except for the total initiation time score. Conversely, age showed a minor effect on these variables (≤2%). Sex also showed a minimal effect (2%). Concerning time scores, initiation time is independent of age, education, and sex. Total execution time score and total problem-solving time score showed a similar discrete effect (up to 11%) for both age and education.

Age-adjusted NEURONORMA scaled scores (NSSA) for the TOLDX and SCWT are presented in Tables 3–12. These tables include percentile ranks, ranges of ages contributing to each normative subsample, and the number of participants contributing to each test's normative estimates. To use the table, select the appropriate column corresponding to the patient's age, find the patient's RS, and subsequently refer to the corresponding NSSA and percentile rank (left part of the table).

As expected, the normative adjustments (NSSA) eliminated the shared variance of age (Table 13). Education, however, continued to account for up to 11%–23% of shared variance with age-adjusted test scores for the SCWT, and up to 10% for the TOLDX. To maintain the same analysis, education adjustments were applied to all variables, although the effect was minor in total initiation time and total problem-solving time scores.

Table 3.

Age-adjusted NEURONORMA scores (NSSA) for age 50–56 (age range for norms = 50–60)

Scaled score Percentile range TOLDX
 
SCWT
 
Total correct score Total move score Total initiation time Total execution time Total problem-solving time Word score Color score Word-color score 
<1 ≥93 ≥308 ≥680 ≥730 ≤24 ≤21 ≤6 
— 92–83 307–273 679–622 729–710 25–43 22–32 
— 82–75 272–174 621–509 709–677 44–55 33–42 8–11 
3–5 — 74–63 173–134 508–452 676–547 56–60 43–46 12–19 
6–10 — 62–54 133–104 451–372 546–481 61–71 47–48 20–21 
11–18 53–48 103–83 371–349 480–414 72–79 49–55 22–25 
19–28 47–42 82–71 348–317 413–368 80–88 56–58 26–31 
29–40 — 41–34 70–54 316–267 367–334 89–96 59–61 32–33 
10 41–59 3–4 33–24 53–42 266–222 333–276 97–100 62–69 34–39 
11 60–71 23–19 41–35 221–176 275–240 101–107 70–74 40–41 
12 72–81 — 18–14 34–30 175–157 239–206 108–112 75–78 42–46 
13 82–89 13–11 29–21 156–139 205–190 113–119 79–81 47–50 
14 90–94 10–6 20–15 138–125 189–171 120–123 82–86 51–54 
15 95–97 — 5–4 14–13 124–115 170–147 124–126 87–93 55–56 
16 98 — 12–11 114–100 146–127 127–130 94–98 57–66 
17 99 10 99–93 126–110 — 99–100 67–72 
18 >99 10 2–0 9–0 ≤92 ≤109 ≥131 ≥101 ≥73 
Sample size  137 137 137 137 137 136 136 136 
Scaled score Percentile range TOLDX
 
SCWT
 
Total correct score Total move score Total initiation time Total execution time Total problem-solving time Word score Color score Word-color score 
<1 ≥93 ≥308 ≥680 ≥730 ≤24 ≤21 ≤6 
— 92–83 307–273 679–622 729–710 25–43 22–32 
— 82–75 272–174 621–509 709–677 44–55 33–42 8–11 
3–5 — 74–63 173–134 508–452 676–547 56–60 43–46 12–19 
6–10 — 62–54 133–104 451–372 546–481 61–71 47–48 20–21 
11–18 53–48 103–83 371–349 480–414 72–79 49–55 22–25 
19–28 47–42 82–71 348–317 413–368 80–88 56–58 26–31 
29–40 — 41–34 70–54 316–267 367–334 89–96 59–61 32–33 
10 41–59 3–4 33–24 53–42 266–222 333–276 97–100 62–69 34–39 
11 60–71 23–19 41–35 221–176 275–240 101–107 70–74 40–41 
12 72–81 — 18–14 34–30 175–157 239–206 108–112 75–78 42–46 
13 82–89 13–11 29–21 156–139 205–190 113–119 79–81 47–50 
14 90–94 10–6 20–15 138–125 189–171 120–123 82–86 51–54 
15 95–97 — 5–4 14–13 124–115 170–147 124–126 87–93 55–56 
16 98 — 12–11 114–100 146–127 127–130 94–98 57–66 
17 99 10 99–93 126–110 — 99–100 67–72 
18 >99 10 2–0 9–0 ≤92 ≤109 ≥131 ≥101 ≥73 
Sample size  137 137 137 137 137 136 136 136 

Note: SCWT = Stroop color-word interference test; TOLDX = Tower of London-Drexel University version.

Table 4.

Age-adjusted NEURONORMA scores (NSSA) for age 57–59 (age range for norms = 53–63)

Scaled score Percentile range TOLDX
 
SCWT
 
Total correct score Total move score Total initiation time Total execution time Total problem-solving time Word score Color score Word-color score 
<1 ≥93 ≥308 ≥680 ≥730 ≤43 ≤32 ≤6 
— 92–83 307–273 679–622 729–695 — 33–36 
— 82–80 272–223 621–524 694–677 44–46 — 8–11 
3–5 — 79–63 222–127 523–483 676–552 47–64 37–45 12–18 
6–10 — 62–54 126–103 482–416 551–513 65–68 46–48 19–20 
11–18 53–48 102–81 415–357 512–419 69–79 49–51 21–25 
19–28 47–41 80–66 356–320 418–373 80–86 52–57 26–29 
29–40 — 40–35 65–55 319–267 372–329 87–93 58–60 30–32 
10 41–59 34–27 54–42 266–234 328–283 94–99 61–67 33–38 
11 60–71 26–22 41–35 233–199 282–256 100–105 68–74 39–41 
12 72–81 21–17 34–32 198–173 255–226 106–110 75–78 42–44 
13 82–89 16–14 31–26 172–156 225–202 111–119 79 45–49 
14 90–94 — 13–11 25–17 155–137 201–192 120–123 80–85 50–54 
15 95–97 10–6 16–14 136–128 191–187 124–126 86–90 55–56 
16 98 — 13–12 127–125 186–182 127–130 91–93 57–66 
17 99 11–9 124–115 181–147 — 94–98 67–72 
18 >99 9–10 3–0 8–0 ≤114 ≤146 ≥131 ≥99 ≥73 
Sample size  133 133 133 133 133 133 133 133 
Scaled score Percentile range TOLDX
 
SCWT
 
Total correct score Total move score Total initiation time Total execution time Total problem-solving time Word score Color score Word-color score 
<1 ≥93 ≥308 ≥680 ≥730 ≤43 ≤32 ≤6 
— 92–83 307–273 679–622 729–695 — 33–36 
— 82–80 272–223 621–524 694–677 44–46 — 8–11 
3–5 — 79–63 222–127 523–483 676–552 47–64 37–45 12–18 
6–10 — 62–54 126–103 482–416 551–513 65–68 46–48 19–20 
11–18 53–48 102–81 415–357 512–419 69–79 49–51 21–25 
19–28 47–41 80–66 356–320 418–373 80–86 52–57 26–29 
29–40 — 40–35 65–55 319–267 372–329 87–93 58–60 30–32 
10 41–59 34–27 54–42 266–234 328–283 94–99 61–67 33–38 
11 60–71 26–22 41–35 233–199 282–256 100–105 68–74 39–41 
12 72–81 21–17 34–32 198–173 255–226 106–110 75–78 42–44 
13 82–89 16–14 31–26 172–156 225–202 111–119 79 45–49 
14 90–94 — 13–11 25–17 155–137 201–192 120–123 80–85 50–54 
15 95–97 10–6 16–14 136–128 191–187 124–126 86–90 55–56 
16 98 — 13–12 127–125 186–182 127–130 91–93 57–66 
17 99 11–9 124–115 181–147 — 94–98 67–72 
18 >99 9–10 3–0 8–0 ≤114 ≤146 ≥131 ≥99 ≥73 
Sample size  133 133 133 133 133 133 133 133 

Note: SCWT = Stroop color-word interference test; TOLDX = Tower of London-Drexel University version.

Table 5.

Age-adjusted NEURONORMA scores (NSSA) for age 60–62 (age range for norms = 56–66)

Scaled score Percentile range TOLDX
 
SCWT
 
Total correct score Total move score Total initiation time Total execution time Total problem-solving time Word score Color score Word-color score 
<1 ≥93 ≥415 ≥740 ≥784 ≤42 ≤20 ≤6 
— 92–83 414–308 739–680 783–730 43 21–32 
— 82–80 307–223 679–622 729–695 — 33–36 8–9 
3–5 — 79–64 222–127 621–483 694–563 44–55 37–40 10–18 
6–10 — 63–57 126–109 482–431 562–529 56–66 41–46 19–20 
11–18 56–49 108–84 430–369 528–445 67–73 47–49 21–24 
19–28 48–42 83–66 368–331 444–378 74–80 50–54 25–26 
29–40 — 41–36 65–54 330–277 377–331 81–90 55–58 27–30 
10 41–59 35–27 53–41 276–234 330–286 91–99 59–65 31–36 
11 60–71 26–22 40–35 233–199 285–256 100–104 66–70 37–41 
12 72–81 21–18 34–31 198–174 255–213 105–110 71–76 42–43 
13 82–89 — 17–14 30–26 173–154 212–202 111–119 77–79 44–47 
14 90–94 13–11 25–20 153–144 201–190 120–123 80–82 48–50 
15 95–97 — 10–9 19–15 143–128 189–172 124–126 83–86 51–55 
16 98 8–6 14 127 171–154 127–130 87–89 — 
17 99 — 13–12 126–125 153–147 — 90 56 
18 >99 8–10 4–0 11–0 ≤124 ≤146 ≥131 ≥91 ≥57 
Sample size  124 124 124 124 124 123 123 123 
Scaled score Percentile range TOLDX
 
SCWT
 
Total correct score Total move score Total initiation time Total execution time Total problem-solving time Word score Color score Word-color score 
<1 ≥93 ≥415 ≥740 ≥784 ≤42 ≤20 ≤6 
— 92–83 414–308 739–680 783–730 43 21–32 
— 82–80 307–223 679–622 729–695 — 33–36 8–9 
3–5 — 79–64 222–127 621–483 694–563 44–55 37–40 10–18 
6–10 — 63–57 126–109 482–431 562–529 56–66 41–46 19–20 
11–18 56–49 108–84 430–369 528–445 67–73 47–49 21–24 
19–28 48–42 83–66 368–331 444–378 74–80 50–54 25–26 
29–40 — 41–36 65–54 330–277 377–331 81–90 55–58 27–30 
10 41–59 35–27 53–41 276–234 330–286 91–99 59–65 31–36 
11 60–71 26–22 40–35 233–199 285–256 100–104 66–70 37–41 
12 72–81 21–18 34–31 198–174 255–213 105–110 71–76 42–43 
13 82–89 — 17–14 30–26 173–154 212–202 111–119 77–79 44–47 
14 90–94 13–11 25–20 153–144 201–190 120–123 80–82 48–50 
15 95–97 — 10–9 19–15 143–128 189–172 124–126 83–86 51–55 
16 98 8–6 14 127 171–154 127–130 87–89 — 
17 99 — 13–12 126–125 153–147 — 90 56 
18 >99 8–10 4–0 11–0 ≤124 ≤146 ≥131 ≥91 ≥57 
Sample size  124 124 124 124 124 123 123 123 

Note: SCWT = Stroop color-word interference test; TOLDX = Tower of London-Drexel University version.

Table 6.

Age-adjusted NEURONORMA scores (NSSA) for age 63–65 (age range for norms = 59–69)

Scaled score Percentile range TOLDX
 
SCWT
 
Total correct score Total move score Total initiation time Total execution time Total problem-solving time Word score Color score Word-color score 
<1 ≥104 ≥415 ≥742 ≥838 ≤42 ≤20 ≤6 
— 103–93 414–223 741–740 837–784 43 21–32 
— 92–73 222–193 739–680 783–730 44–45 33–36 8–9 
3–5 — 72–63 192–123 679–515 729–565 46–53 37–40 10–13 
6–10 — 62–61 122–109 514–460 564–538 54–60 41–42 14–15 
11–18 60–50 108–81 459–382 537–459 61–70 43–47 16–21 
19–28 49–46 80–66 381–341 458–413 71–76 48–49 22–24 
29–40 — 45–37 65–54 340–281 412–344 77–84 50–56 25–28 
10 41–59 36–28 53–44 280–244 343–308 85–97 57–62 29–34 
11 60–71 27–24 43–37 243–215 307–276 98–99 63–68 35–38 
12 72–81 23–19 36–32 214–182 275–244 100–103 69–74 39–41 
13 82–89 18–14 31–28 181–169 243–207 104–114 75–78 42–45 
14 90–94 — 13–11 27–22 168–150 206–191 115–120 79 46–49 
15 95–97 10–7 21–18 149–130 190–172 121–124 80–82 50–53 
16 98 — — 129–128 171–154 125–130 83–84 54 
17 99 — 17–16 127 153–147 — 85–90 55 
18 >99 8–10 4–0 ≤15 ≤126 ≤146 ≥131 ≥91 ≥56 
Sample size  106 106 106 106 106 106 106 106 
Scaled score Percentile range TOLDX
 
SCWT
 
Total correct score Total move score Total initiation time Total execution time Total problem-solving time Word score Color score Word-color score 
<1 ≥104 ≥415 ≥742 ≥838 ≤42 ≤20 ≤6 
— 103–93 414–223 741–740 837–784 43 21–32 
— 92–73 222–193 739–680 783–730 44–45 33–36 8–9 
3–5 — 72–63 192–123 679–515 729–565 46–53 37–40 10–13 
6–10 — 62–61 122–109 514–460 564–538 54–60 41–42 14–15 
11–18 60–50 108–81 459–382 537–459 61–70 43–47 16–21 
19–28 49–46 80–66 381–341 458–413 71–76 48–49 22–24 
29–40 — 45–37 65–54 340–281 412–344 77–84 50–56 25–28 
10 41–59 36–28 53–44 280–244 343–308 85–97 57–62 29–34 
11 60–71 27–24 43–37 243–215 307–276 98–99 63–68 35–38 
12 72–81 23–19 36–32 214–182 275–244 100–103 69–74 39–41 
13 82–89 18–14 31–28 181–169 243–207 104–114 75–78 42–45 
14 90–94 — 13–11 27–22 168–150 206–191 115–120 79 46–49 
15 95–97 10–7 21–18 149–130 190–172 121–124 80–82 50–53 
16 98 — — 129–128 171–154 125–130 83–84 54 
17 99 — 17–16 127 153–147 — 85–90 55 
18 >99 8–10 4–0 ≤15 ≤126 ≤146 ≥131 ≥91 ≥56 
Sample size  106 106 106 106 106 106 106 106 

Note: SCWT = Stroop color-word interference test; TOLDX = Tower of London-Drexel University version.

Table 7.

Age-adjusted NEURONORMA scores (NSSA) for age 66–68 (age range for norms = 62–72)

Scaled score Percentile range TOLDX
 
SCWT
 
Total correct score Total move score Total initiation time Total execution time Total problem-solving time Word score Color score Word-color score 
<1 ≥104 ≥415 ≥742 ≥838 ≤30 ≤20 ≤5 
— 103–74 414–270 741–740 837–832 31–42 21–23 — 
— 73 269–260 739–671 831–784 43–45 24–26 6–9 
3–5 — 72–63 259–184 670–524 783–630 46–57 27–38 10–13 
6–10 — 62–57 183–115 523–463 629–559 58–65 39–40 14–17 
11–18 56–49 114–96 462–396 558–479 66–71 41–45 18–21 
19–28 48–42 95–80 395–354 478–434 72–77 46–49 22–24 
29–40 — 41–36 79–66 353–310 433–377 78–82 50–53 25–26 
10 41–59 3–4 35–27 65–48 309–243 376–319 83–91 54–59 27–30 
11 60–71 — 26–21 47–42 242–214 318–267 92–98 60–62 31–35 
12 72–81 20–17 41–32 213–180 266–242 99–108 63–67 36–39 
13 82–89 16–14 31–28 179–169 241–205 109–115 68–73 40–43 
14 90–94 — 13–10 27–24 168–153 204–191 116–120 74–76 44–47 
15 95–97 9–7 23–18 152–135 190–184 121–124 77–79 48–50 
16 98 — — — 134–130 183–172 125–130 80–82 51 
17 99 — 17–16 129–127 171–154 — 83–84 52–54 
18 >99 8–10 5–0 ≤15 ≤126 ≤153 ≥131 ≥85 ≥55 
Sample size  120 120 120 120 120 119 119 119≤≤ 
Scaled score Percentile range TOLDX
 
SCWT
 
Total correct score Total move score Total initiation time Total execution time Total problem-solving time Word score Color score Word-color score 
<1 ≥104 ≥415 ≥742 ≥838 ≤30 ≤20 ≤5 
— 103–74 414–270 741–740 837–832 31–42 21–23 — 
— 73 269–260 739–671 831–784 43–45 24–26 6–9 
3–5 — 72–63 259–184 670–524 783–630 46–57 27–38 10–13 
6–10 — 62–57 183–115 523–463 629–559 58–65 39–40 14–17 
11–18 56–49 114–96 462–396 558–479 66–71 41–45 18–21 
19–28 48–42 95–80 395–354 478–434 72–77 46–49 22–24 
29–40 — 41–36 79–66 353–310 433–377 78–82 50–53 25–26 
10 41–59 3–4 35–27 65–48 309–243 376–319 83–91 54–59 27–30 
11 60–71 — 26–21 47–42 242–214 318–267 92–98 60–62 31–35 
12 72–81 20–17 41–32 213–180 266–242 99–108 63–67 36–39 
13 82–89 16–14 31–28 179–169 241–205 109–115 68–73 40–43 
14 90–94 — 13–10 27–24 168–153 204–191 116–120 74–76 44–47 
15 95–97 9–7 23–18 152–135 190–184 121–124 77–79 48–50 
16 98 — — — 134–130 183–172 125–130 80–82 51 
17 99 — 17–16 129–127 171–154 — 83–84 52–54 
18 >99 8–10 5–0 ≤15 ≤126 ≤153 ≥131 ≥85 ≥55 
Sample size  120 120 120 120 120 119 119 119≤≤ 

Note: SCWT = Stroop color-word interference test; TOLDX = Tower of London-Drexel University version.

Table 8.

Age-adjusted NEURONORMA scores (NSSA) for age 69–71 (age range for norms = 65–75)

Scaled score Percentile range TOLDX
 
SCWT
 
Total correct score Total move score Total initiation time Total execution time Total problem-solving time Word score Color score Word-color score 
<1 ≥104 ≥270 ≥793 ≥876 ≤23 ≤21 ≤5 
— 103–93 269–260 792–742 875–838 24–30 — — 
— 92–77 259–226 741–740 837–832 31–32 22–23 6–9 
3–5 — 76–69 225–184 739–623 831–736 33–53 24–32 10–11 
6–10 — 68–61 183–110 622–519 735–591 54–59 33–38 12–14 
11–18 60–51 109–94 518–452 590–541 60–70 39–43 15–19 
19–28 50–45 93–80 451–372 540–459 71–73 44–47 20–23 
29–40 — 44–38 79–66 371–335 458–407 74–79 48–50 24–25 
10 41–59 3–4 37–29 65–49 334–268 406–329 80–90 51–56 26–29 
11 60–71 — 28–23 48–43 267–216 328–277 91–96 57–60 30–33 
12 72–81 22–18 42–37 215–181 276–242 97–98 61–63 34–36 
13 82–89 17–14 36–30 180–171 241–205 99–106 64–70 37–42 
14 90–94 — 13–10 29–24 170–153 204–191 107–112 71–74 43–44 
15 95–97 9–7 23–22 152–135 190–184 113–115 75–76 45–46 
16 98 — — 21–18 134–130 183–172 116–120 77 47–50 
17 99 — — 129–127 171–154 121–130 78–82 51 
18 >99 8–10 5–0 ≤17 ≤126 ≤153 ≥131 ≥83 ≥52 
Sample size  125 125 125 125 125 124 124 124≤ 
Scaled score Percentile range TOLDX
 
SCWT
 
Total correct score Total move score Total initiation time Total execution time Total problem-solving time Word score Color score Word-color score 
<1 ≥104 ≥270 ≥793 ≥876 ≤23 ≤21 ≤5 
— 103–93 269–260 792–742 875–838 24–30 — — 
— 92–77 259–226 741–740 837–832 31–32 22–23 6–9 
3–5 — 76–69 225–184 739–623 831–736 33–53 24–32 10–11 
6–10 — 68–61 183–110 622–519 735–591 54–59 33–38 12–14 
11–18 60–51 109–94 518–452 590–541 60–70 39–43 15–19 
19–28 50–45 93–80 451–372 540–459 71–73 44–47 20–23 
29–40 — 44–38 79–66 371–335 458–407 74–79 48–50 24–25 
10 41–59 3–4 37–29 65–49 334–268 406–329 80–90 51–56 26–29 
11 60–71 — 28–23 48–43 267–216 328–277 91–96 57–60 30–33 
12 72–81 22–18 42–37 215–181 276–242 97–98 61–63 34–36 
13 82–89 17–14 36–30 180–171 241–205 99–106 64–70 37–42 
14 90–94 — 13–10 29–24 170–153 204–191 107–112 71–74 43–44 
15 95–97 9–7 23–22 152–135 190–184 113–115 75–76 45–46 
16 98 — — 21–18 134–130 183–172 116–120 77 47–50 
17 99 — — 129–127 171–154 121–130 78–82 51 
18 >99 8–10 5–0 ≤17 ≤126 ≤153 ≥131 ≥83 ≥52 
Sample size  125 125 125 125 125 124 124 124≤ 

Note: SCWT = Stroop color-word interference test; TOLDX = Tower of London-Drexel University version.

Table 9.

Age-adjusted NEURONORMA scores (NSSA) for age 72–74 (age range for norms = 68–78)

Scaled score Percentile range TOLDX
 
SCWT
 
Total correct score Total move score Total initiation time Total execution time Total problem-solving time Word score Color score Word-color score 
<1 ≥104 ≥270 ≥793 ≥876 ≤23 ≤21 ≤5 
— 103–93 269–260 792–742 875–838 24–30 — 6–8 
— 92–79 259–226 741–725 837–832 31–32 22–23 — 
3–5 — 78–72 225–184 724–623 831–736 33–47 24–29 9–10 
6–10 — 71–61 183–116 622–550 735–641 48–59 30–36 11–13 
11–18 60–51 115–94 549–483 640–562 60–67 37–40 14–17 
19–28 50–45 93–79 482–410 561–481 68–75 41–45 18–20 
29–40 — 44–39 78–66 409–350 480–433 76–81 46–49 21–24 
10 41–59 38–32 65–51 349–274 432–335 82–89 50–55 25–27 
11 60–71 31–26 50–45 273–239 334–298 90–95 56–60 28–30 
12 72–81 25–20 44–40 238–203 297–257 96–98 61–62 31–36 
13 82–89 19–16 39–31 202–180 256–230 99–104 63–67 37–40 
14 90–94 — 15–11 30–25 179–171 229–203 105–111 68–71 41–44 
15 95–97 10–8 24–22 170–160 202–192 112–114 72–76 45–46 
16 98 — — 159–158 191–189 115–120 77 — 
17 99 — 21–18 157–152 188–186 121–123 78–82 47–50 
18 >99 9–10 6–0 ≤17 ≤151 ≤185 ≥124 ≥83 ≥51 
Sample size  126 126 126 126 126 124 124 124 
Scaled score Percentile range TOLDX
 
SCWT
 
Total correct score Total move score Total initiation time Total execution time Total problem-solving time Word score Color score Word-color score 
<1 ≥104 ≥270 ≥793 ≥876 ≤23 ≤21 ≤5 
— 103–93 269–260 792–742 875–838 24–30 — 6–8 
— 92–79 259–226 741–725 837–832 31–32 22–23 — 
3–5 — 78–72 225–184 724–623 831–736 33–47 24–29 9–10 
6–10 — 71–61 183–116 622–550 735–641 48–59 30–36 11–13 
11–18 60–51 115–94 549–483 640–562 60–67 37–40 14–17 
19–28 50–45 93–79 482–410 561–481 68–75 41–45 18–20 
29–40 — 44–39 78–66 409–350 480–433 76–81 46–49 21–24 
10 41–59 38–32 65–51 349–274 432–335 82–89 50–55 25–27 
11 60–71 31–26 50–45 273–239 334–298 90–95 56–60 28–30 
12 72–81 25–20 44–40 238–203 297–257 96–98 61–62 31–36 
13 82–89 19–16 39–31 202–180 256–230 99–104 63–67 37–40 
14 90–94 — 15–11 30–25 179–171 229–203 105–111 68–71 41–44 
15 95–97 10–8 24–22 170–160 202–192 112–114 72–76 45–46 
16 98 — — 159–158 191–189 115–120 77 — 
17 99 — 21–18 157–152 188–186 121–123 78–82 47–50 
18 >99 9–10 6–0 ≤17 ≤151 ≤185 ≥124 ≥83 ≥51 
Sample size  126 126 126 126 126 124 124 124 

Note: SCWT = Stroop color-word interference test; TOLDX = Tower of London-Drexel University version.

Table 10.

Age-adjusted NEURONORMA scores (NSSA) for age 75–77 (age range for norms = 71–81)

Scaled score Percentile range TOLDX
 
SCWT
 
Total correct score Total move score Total initiation time Total execution time Total problem-solving time Word score Color score Word-color score 
<1 ≥93 ≥260 ≥793 ≥876 ≤22 ≤20 ≤4 
— 92–79 259–226 792–725 875–832 23 — 
— 78 225–221 724–697 831–767 24–30 21 6–8 
3–5 — 77–69 220–166 696–623 766–736 31–41 22–27 
6–10 — 68–59 165–109 622–571 735–641 42–54 28–32 10–11 
11–18 58–50 108–94 570–506 640–579 55–61 33–39 12–15 
19–28 — 49–45 93–80 505–443 578–498 62–70 40–45 16–18 
29–40 44–40 79–67 442–354 497–443 71–77 46–48 19–21 
10 41–59 39–31 68–53 353–288 442–354 78–85 49–54 22–26 
11 60–71 30–26 52–43 287–251 353–311 86–91 55–57 27–28 
12 72–81 25–20 42–39 250–214 310–261 92–96 58–60 29–34 
13 82–89 19–14 38–33 213–186 260–239 97–100 61–66 35–38 
14 90–94 — 13–12 32–29 185–172 238–216 101–109 67–69 39–43 
15 95–97 11–8 28–24 171–166 215–196 110–114 70–73 44 
16 98 — 23–22 165–160 195–186 115–119 74 45 
17 99 — 21–18 159–144 185–184 120 75–77 — 
18 >99 9–10 6–0 ≤17 ≤183 ≤184 ≥121 ≥78 ≥46 
Sample size  102 102 102 102 102 98 98 98 
Scaled score Percentile range TOLDX
 
SCWT
 
Total correct score Total move score Total initiation time Total execution time Total problem-solving time Word score Color score Word-color score 
<1 ≥93 ≥260 ≥793 ≥876 ≤22 ≤20 ≤4 
— 92–79 259–226 792–725 875–832 23 — 
— 78 225–221 724–697 831–767 24–30 21 6–8 
3–5 — 77–69 220–166 696–623 766–736 31–41 22–27 
6–10 — 68–59 165–109 622–571 735–641 42–54 28–32 10–11 
11–18 58–50 108–94 570–506 640–579 55–61 33–39 12–15 
19–28 — 49–45 93–80 505–443 578–498 62–70 40–45 16–18 
29–40 44–40 79–67 442–354 497–443 71–77 46–48 19–21 
10 41–59 39–31 68–53 353–288 442–354 78–85 49–54 22–26 
11 60–71 30–26 52–43 287–251 353–311 86–91 55–57 27–28 
12 72–81 25–20 42–39 250–214 310–261 92–96 58–60 29–34 
13 82–89 19–14 38–33 213–186 260–239 97–100 61–66 35–38 
14 90–94 — 13–12 32–29 185–172 238–216 101–109 67–69 39–43 
15 95–97 11–8 28–24 171–166 215–196 110–114 70–73 44 
16 98 — 23–22 165–160 195–186 115–119 74 45 
17 99 — 21–18 159–144 185–184 120 75–77 — 
18 >99 9–10 6–0 ≤17 ≤183 ≤184 ≥121 ≥78 ≥46 
Sample size  102 102 102 102 102 98 98 98 

Note: SCWT = Stroop color-word interference test; TOLDX = Tower of London-Drexel University version.

Table 11.

Age-adjusted NEURONORMA scores (NSSA) for age 78–80 (age range for norms = 74–84)

Scaled score Percentile range TOLDX
 
SCWT
 
Total correct score Total move score Total initiation time Total execution time Total problem-solving time Word score Color score Word-color score 
<1 ≥94 ≥227 ≥794 ≥877 ≤31 ≤20 ≤7 
— 93 226 793 876 32 21 
— — — — — — — — 
3–5 — 92–78 225–166 792–697 875–736 33–41 22–27 
6–10 77–61 165–116 696–595 735–662 42–50 28–32 10–11 
11–18 — 60–50 115–98 594–510 661–601 51–55 33–35 12–14 
19–28 — 49–43 97–83 509–473 600–541 56–67 36–40 15–17 
29–40 42–40 80–73 472–407 540–481 68–75 41–46 18–19 
10 41–59 39–32 72–60 406–301 480–392 76–83 47–51 20–23 
11 60–71 31–26 59–51 300–272 391–330 84–89 52–54 24–26 
12 72–81 — 25–22 50–42 271–251 329–306 90–97 55–60 27–31 
13 82–89 5–6 21–16 41–34 250–214 305–256 98–100 61–64 32–36 
14 90–94 — 15–13 33–30 213–189 255–230 101–104 65–68 37–38 
15 95–97 — 12–9 29 188–172 229–218 105–114 69 39–40 
16 98 8–7 28–26 171–144 217–186 115–119 70–71 41–42 
17 99 — — — — — — — — 
18 >99 8–10 6–0 ≤25 ≤143 ≤185 ≥120 ≥72 ≥43 
Sample size  66 66 66 66 66 65 65 65 
Scaled score Percentile range TOLDX
 
SCWT
 
Total correct score Total move score Total initiation time Total execution time Total problem-solving time Word score Color score Word-color score 
<1 ≥94 ≥227 ≥794 ≥877 ≤31 ≤20 ≤7 
— 93 226 793 876 32 21 
— — — — — — — — 
3–5 — 92–78 225–166 792–697 875–736 33–41 22–27 
6–10 77–61 165–116 696–595 735–662 42–50 28–32 10–11 
11–18 — 60–50 115–98 594–510 661–601 51–55 33–35 12–14 
19–28 — 49–43 97–83 509–473 600–541 56–67 36–40 15–17 
29–40 42–40 80–73 472–407 540–481 68–75 41–46 18–19 
10 41–59 39–32 72–60 406–301 480–392 76–83 47–51 20–23 
11 60–71 31–26 59–51 300–272 391–330 84–89 52–54 24–26 
12 72–81 — 25–22 50–42 271–251 329–306 90–97 55–60 27–31 
13 82–89 5–6 21–16 41–34 250–214 305–256 98–100 61–64 32–36 
14 90–94 — 15–13 33–30 213–189 255–230 101–104 65–68 37–38 
15 95–97 — 12–9 29 188–172 229–218 105–114 69 39–40 
16 98 8–7 28–26 171–144 217–186 115–119 70–71 41–42 
17 99 — — — — — — — — 
18 >99 8–10 6–0 ≤25 ≤143 ≤185 ≥120 ≥72 ≥43 
Sample size  66 66 66 66 66 65 65 65 

Note: SCWT = Stroop color-word interference test; TOLDX = Tower of London-Drexel University version.

Table 12.

Age-adjusted NEURONORMA scores (NSSA) for age 81–90 (age range for norms = 77–90)

Scaled score Percentile range TOLDX
 
SCWT
 
Total correct score Total move score Total initiation time Total execution time Total problem-solving time Word score Color score Word-color score 
<1 ≥103 ≥222 ≥874 ≥968 ≤20 ≤17 ≤7 
— — — — — — — — 
— 102 221 873 967 21 18 
3–5 — 101–79 220–140 872–709 966–782 22–41 19–21 
6–10 78–77 139–118 708–600 781–711 42–50 22–32 10 
11–18 — 76–57 117–106 599–571 710–634 51–54 33–35 11–14 
19–28 56–46 105–89 570–499 633–576 55–65 36–40 15–16 
29–40 — 44–40 88–73 498–407 575–474 66–75 41–46 17–18 
10 41–59 39–29 72–62 406–303 473–395 76–83 47–49 19–22 
11 60–71 — 28–26 61–49 302–272 394–354 84–88 50–54 23–25 
12 72–81 4–5 25–22 48–41 271–251 353–307 89–95 55–58 26–27 
13 82–89 — 21–18 39–35 250–237 306–298 96–99 59–60 28–34 
14 90–94 17–13 34–31 236–214 297–282 100–104 61–66 35–36 
15 95–97 — 12–11 — 213–203 281–256 105–114 67–68 37 
16 98 10–9 30 202–189 255–252 115–119 69–71 38–40 
17 99 — — — — — — — — 
18 >99 8–10 7–0 ≤29 ≤188 ≤251 ≥120 ≥72 ≥41 
Sample size  41 41 41 41 41 41 41 41 
Scaled score Percentile range TOLDX
 
SCWT
 
Total correct score Total move score Total initiation time Total execution time Total problem-solving time Word score Color score Word-color score 
<1 ≥103 ≥222 ≥874 ≥968 ≤20 ≤17 ≤7 
— — — — — — — — 
— 102 221 873 967 21 18 
3–5 — 101–79 220–140 872–709 966–782 22–41 19–21 
6–10 78–77 139–118 708–600 781–711 42–50 22–32 10 
11–18 — 76–57 117–106 599–571 710–634 51–54 33–35 11–14 
19–28 56–46 105–89 570–499 633–576 55–65 36–40 15–16 
29–40 — 44–40 88–73 498–407 575–474 66–75 41–46 17–18 
10 41–59 39–29 72–62 406–303 473–395 76–83 47–49 19–22 
11 60–71 — 28–26 61–49 302–272 394–354 84–88 50–54 23–25 
12 72–81 4–5 25–22 48–41 271–251 353–307 89–95 55–58 26–27 
13 82–89 — 21–18 39–35 250–237 306–298 96–99 59–60 28–34 
14 90–94 17–13 34–31 236–214 297–282 100–104 61–66 35–36 
15 95–97 — 12–11 — 213–203 281–256 105–114 67–68 37 
16 98 10–9 30 202–189 255–252 115–119 69–71 38–40 
17 99 — — — — — — — — 
18 >99 8–10 7–0 ≤29 ≤188 ≤251 ≥120 ≥72 ≥41 
Sample size  41 41 41 41 41 41 41 41 

Note: SCWT = Stroop color-word interference test; TOLDX = Tower of London-Drexel University version.

Table 13.

Correlations (r) and shared variances (r2) of NEURONORMA subtest scores with age and years of education

Measure Age (years)
 
Education (years)
 
r r2 r r2 
SCWT 
 Part A: Word −0.038 0.00144 0.48876 0.23889 
 Part B: Color −0.057 0.00325 0.40354 0.16284 
 Part C: Interference −0.066 0.00436 0.34169 0.11675 
TOLDX 
 Total moves score −0.0112 0.00013 0.31929 0.10195 
 Total correct score −0.0097 0.00009 0.30246 0.09148 
 Total initiation time score −0.0144 0.00021 −0.122 0.01487 
 Total execution time score −0.0356 0.00126 0.29159 0.08502 
 Total problem-solving time score −0.0344 0.00118 0.22066 0.04869 
Measure Age (years)
 
Education (years)
 
r r2 r r2 
SCWT 
 Part A: Word −0.038 0.00144 0.48876 0.23889 
 Part B: Color −0.057 0.00325 0.40354 0.16284 
 Part C: Interference −0.066 0.00436 0.34169 0.11675 
TOLDX 
 Total moves score −0.0112 0.00013 0.31929 0.10195 
 Total correct score −0.0097 0.00009 0.30246 0.09148 
 Total initiation time score −0.0144 0.00021 −0.122 0.01487 
 Total execution time score −0.0356 0.00126 0.29159 0.08502 
 Total problem-solving time score −0.0344 0.00118 0.22066 0.04869 

Note: SCWT = Stroop color-word interference test; TOLDX = Tower of London-Drexel University version.

The transformation of RS to NSSA produced a normalized distribution on which linear regressions could be applied. Regression coefficients from this analysis were used as the basis for education (years) adjustments. From these data, we have constructed adjustment tables to help the clinician make the necessary adjustment (Tables 14–16 for the SCWT, and Tables 17–21 for the TOLDX). These tables include the respective values of β for every variable.

Table 14.

Stroop color-word interference test part A (word)

NSSA Education (years)
 
10 11 12 13 14 15 16 17 18 19 20 
−1 
10 
11 10 10 10 10 
12 11 11 11 11 10 10 10 10 
10 13 12 12 12 12 11 11 11 11 10 10 10 10 
11 14 13 13 13 13 12 12 12 12 11 11 11 11 10 10 10 
12 15 14 14 14 14 13 13 13 13 12 12 12 12 11 11 11 10 10 10 10 
13 16 15 15 15 15 14 14 14 14 13 13 13 13 12 12 12 11 11 11 11 10 
14 17 16 16 16 16 15 15 15 15 14 14 14 14 13 13 13 12 12 12 12 11 
15 18 17 17 17 17 16 16 16 16 15 15 15 15 14 14 14 13 13 13 13 12 
16 19 18 18 18 18 17 17 17 17 16 16 16 16 15 15 15 14 14 14 14 13 
17 20 19 19 19 19 18 18 18 18 17 17 17 17 16 16 16 15 15 15 15 14 
18 21 20 20 20 20 19 19 19 19 18 18 18 18 17 17 17 16 16 16 16 15 
NSSA Education (years)
 
10 11 12 13 14 15 16 17 18 19 20 
−1 
10 
11 10 10 10 10 
12 11 11 11 11 10 10 10 10 
10 13 12 12 12 12 11 11 11 11 10 10 10 10 
11 14 13 13 13 13 12 12 12 12 11 11 11 11 10 10 10 
12 15 14 14 14 14 13 13 13 13 12 12 12 12 11 11 11 10 10 10 10 
13 16 15 15 15 15 14 14 14 14 13 13 13 13 12 12 12 11 11 11 11 10 
14 17 16 16 16 16 15 15 15 15 14 14 14 14 13 13 13 12 12 12 12 11 
15 18 17 17 17 17 16 16 16 16 15 15 15 15 14 14 14 13 13 13 13 12 
16 19 18 18 18 18 17 17 17 17 16 16 16 16 15 15 15 14 14 14 14 13 
17 20 19 19 19 19 18 18 18 18 17 17 17 17 16 16 16 15 15 15 15 14 
18 21 20 20 20 20 19 19 19 19 18 18 18 18 17 17 17 16 16 16 16 15 

Note: Education adjustment applying the following formula: NSSA&E = NSSA − (β × [Education(years) – 12]), where β = 0.25663.

Table 15.

Stroop color-word interference test part B (color)

NSSA Education (years)
 
10 11 12 13 14 15 16 17 18 19 20 
10 10 10 
11 11 11 10 10 10 10 10 
10 12 12 12 11 11 11 11 11 10 10 10 10 10 
11 13 13 13 12 12 12 12 12 11 11 11 11 11 10 10 10 10 
12 14 14 14 13 13 13 13 13 12 12 12 12 12 11 11 11 11 10 10 10 10 
13 15 15 15 14 14 14 14 14 13 13 13 13 13 12 12 12 12 11 11 11 11 
14 16 16 16 15 15 15 15 15 14 14 14 14 14 13 13 13 13 12 12 12 12 
15 17 17 17 16 16 16 16 16 15 15 15 15 15 14 14 14 14 13 13 13 13 
16 18 18 18 17 17 17 17 17 16 16 16 16 16 15 15 15 15 14 14 14 14 
17 19 19 19 18 18 18 18 18 17 17 17 17 17 16 16 16 16 15 15 15 15 
18 20 20 20 19 19 19 19 19 18 18 18 18 18 17 17 17 17 16 16 16 16 
NSSA Education (years)
 
10 11 12 13 14 15 16 17 18 19 20 
10 10 10 
11 11 11 10 10 10 10 10 
10 12 12 12 11 11 11 11 11 10 10 10 10 10 
11 13 13 13 12 12 12 12 12 11 11 11 11 11 10 10 10 10 
12 14 14 14 13 13 13 13 13 12 12 12 12 12 11 11 11 11 10 10 10 10 
13 15 15 15 14 14 14 14 14 13 13 13 13 13 12 12 12 12 11 11 11 11 
14 16 16 16 15 15 15 15 15 14 14 14 14 14 13 13 13 13 12 12 12 12 
15 17 17 17 16 16 16 16 16 15 15 15 15 15 14 14 14 14 13 13 13 13 
16 18 18 18 17 17 17 17 17 16 16 16 16 16 15 15 15 15 14 14 14 14 
17 19 19 19 18 18 18 18 18 17 17 17 17 17 16 16 16 16 15 15 15 15 
18 20 20 20 19 19 19 19 19 18 18 18 18 18 17 17 17 17 16 16 16 16 

Note: Education adjustment applying the following formula: NSSA&E = NSSA − (β × [Education(years) – 12]), where β = 0.2099.

Table 16.

Stroop color-word interference test part C (interference)

NSSA Education (years)
 
10 11 12 13 14 15 16 17 18 19 20 
10 
11 10 10 10 10 10 10 
10 12 11 11 11 11 11 11 10 10 10 10 10 10 
11 13 12 12 12 12 12 12 11 11 11 11 11 11 10 10 10 10 10 
12 14 13 13 13 13 13 13 12 12 12 12 12 12 11 11 11 11 11 10 10 10 
13 15 14 14 14 14 14 14 13 13 13 13 13 13 12 12 12 12 12 11 11 11 
14 16 15 15 15 15 15 15 14 14 14 14 14 14 13 13 13 13 13 12 12 12 
15 17 16 16 16 16 16 16 15 15 15 15 15 15 14 14 14 14 14 13 13 13 
16 18 17 17 17 17 17 17 16 16 16 16 16 16 15 15 15 15 15 14 14 14 
17 19 18 18 18 18 18 18 17 17 17 17 17 17 16 16 16 16 16 15 15 15 
18 20 19 19 19 19 19 19 18 18 18 18 18 18 17 17 17 17 17 16 16 16 
NSSA Education (years)
 
10 11 12 13 14 15 16 17 18 19 20 
10 
11 10 10 10 10 10 10 
10 12 11 11 11 11 11 11 10 10 10 10 10 10 
11 13 12 12 12 12 12 12 11 11 11 11 11 11 10 10 10 10 10 
12 14 13 13 13 13 13 13 12 12 12 12 12 12 11 11 11 11 11 10 10 10 
13 15 14 14 14 14 14 14 13 13 13 13 13 13 12 12 12 12 12 11 11 11 
14 16 15 15 15 15 15 15 14 14 14 14 14 14 13 13 13 13 13 12 12 12 
15 17 16 16 16 16 16 16 15 15 15 15 15 15 14 14 14 14 14 13 13 13 
16 18 17 17 17 17 17 17 16 16 16 16 16 16 15 15 15 15 15 14 14 14 
17 19 18 18 18 18 18 18 17 17 17 17 17 17 16 16 16 16 16 15 15 15 
18 20 19 19 19 19 19 19 18 18 18 18 18 18 17 17 17 17 17 16 16 16 

Note: Education adjustment applying the following formula: NSSA&E = NSSA – (β × [Education(years) – 12]), where β = 0.17826.

Table 17.

Tower of LondonDX: Total moves score

NSSA Education (years)
 
10 11 12 13 14 15 16 17 18 19 20 
10 10 10 10 10 10 
10 11 11 11 11 11 11 10 10 10 10 10 10 10 
11 12 12 12 12 12 12 11 11 11 11 11 11 11 10 10 10 10 10 10 
12 13 13 13 13 13 13 12 12 12 12 12 12 12 11 11 11 11 11 11 10 10 
13 14 14 14 14 14 14 13 13 13 13 13 13 13 12 12 12 12 12 12 11 11 
14 15 15 15 15 15 15 14 14 14 14 14 14 14 13 13 13 13 13 13 12 12 
15 16 16 16 16 16 16 15 15 15 15 15 15 15 14 14 14 14 14 14 13 13 
16 17 17 17 17 17 17 16 16 16 16 16 16 16 15 15 15 15 15 15 14 14 
17 18 18 18 18 18 18 17 17 17 17 17 17 17 16 16 16 16 16 16 15 15 
18 19 19 19 19 19 19 18 18 18 18 18 18 18 17 17 17 17 17 17 16 16 
NSSA Education (years)
 
10 11 12 13 14 15 16 17 18 19 20 
10 10 10 10 10 10 
10 11 11 11 11 11 11 10 10 10 10 10 10 10 
11 12 12 12 12 12 12 11 11 11 11 11 11 11 10 10 10 10 10 10 
12 13 13 13 13 13 13 12 12 12 12 12 12 12 11 11 11 11 11 11 10 10 
13 14 14 14 14 14 14 13 13 13 13 13 13 13 12 12 12 12 12 12 11 11 
14 15 15 15 15 15 15 14 14 14 14 14 14 14 13 13 13 13 13 13 12 12 
15 16 16 16 16 16 16 15 15 15 15 15 15 15 14 14 14 14 14 14 13 13 
16 17 17 17 17 17 17 16 16 16 16 16 16 16 15 15 15 15 15 15 14 14 
17 18 18 18 18 18 18 17 17 17 17 17 17 17 16 16 16 16 16 16 15 15 
18 19 19 19 19 19 19 18 18 18 18 18 18 18 17 17 17 17 17 17 16 16 

Note: Education adjustment applying the following formula: NSSA&E = NSSA – (β × [Education(years) – 12]), where β = 0.16314.

Table 18.

Tower of LondonDX: Total correct score

NSSA Education (years)
 
10 11 12 13 14 15 16 17 18 19 20 
10 10 10 10 10 10 
10 11 11 11 11 11 11 10 10 10 10 10 10 10 
11 12 12 12 12 12 12 11 11 11 11 11 11 11 10 10 10 10 10 10 
12 13 13 13 13 13 13 12 12 12 12 12 12 12 11 11 11 11 11 11 10 10 
13 14 14 14 14 14 14 13 13 13 13 13 13 13 12 12 12 12 12 12 11 11 
14 15 15 15 15 15 15 14 14 14 14 14 14 14 13 13 13 13 13 13 12 12 
15 16 16 16 16 16 16 15 15 15 15 15 15 15 14 14 14 14 14 14 13 13 
16 17 17 17 17 17 17 16 16 16 16 16 16 16 15 15 15 15 15 15 14 14 
17 18 18 18 18 18 18 17 17 17 17 17 17 17 16 16 16 16 16 16 15 15 
18 19 19 19 19 19 19 18 18 18 18 18 18 18 17 17 17 17 17 17 16 16 
NSSA Education (years)
 
10 11 12 13 14 15 16 17 18 19 20 
10 10 10 10 10 10 
10 11 11 11 11 11 11 10 10 10 10 10 10 10 
11 12 12 12 12 12 12 11 11 11 11 11 11 11 10 10 10 10 10 10 
12 13 13 13 13 13 13 12 12 12 12 12 12 12 11 11 11 11 11 11 10 10 
13 14 14 14 14 14 14 13 13 13 13 13 13 13 12 12 12 12 12 12 11 11 
14 15 15 15 15 15 15 14 14 14 14 14 14 14 13 13 13 13 13 13 12 12 
15 16 16 16 16 16 16 15 15 15 15 15 15 15 14 14 14 14 14 14 13 13 
16 17 17 17 17 17 17 16 16 16 16 16 16 16 15 15 15 15 15 15 14 14 
17 18 18 18 18 18 18 17 17 17 17 17 17 17 16 16 16 16 16 16 15 15 
18 19 19 19 19 19 19 18 18 18 18 18 18 18 17 17 17 17 17 17 16 16 

Note: Education adjustment applying the following formula: NSSA&E = NSSA – (β × [Education(years) – 12]), where β = 0.15447.

Table 19.

Tower of LondonDX: Total time score

SSSA Education (years)
 
10 11 12 13 14 15 16 17 18 19 20 
10 10 10 10 10 10 10 10 10 10 
11 11 11 11 11 11 11 11 11 11 10 10 10 10 10 10 10 10 10 10 10 10 
12 12 12 12 12 12 12 12 12 12 11 11 11 11 11 11 11 11 11 11 11 11 
13 13 13 13 13 13 13 13 13 13 12 12 12 12 12 12 12 12 12 12 12 12 
14 14 14 14 14 14 14 14 14 14 13 13 13 13 13 13 13 13 13 13 13 13 
15 15 15 15 15 15 15 15 15 15 14 14 14 14 14 14 14 14 14 14 14 14 
16 16 16 16 16 16 16 16 16 16 15 15 15 15 15 15 15 15 15 15 15 15 
17 17 17 17 17 17 17 17 17 17 16 16 16 16 16 16 16 16 16 16 16 16 
18 18 18 18 18 18 18 18 18 18 17 17 17 17 17 17 17 17 17 17 17 17 
SSSA Education (years)
 
10 11 12 13 14 15 16 17 18 19 20 
10 10 10 10 10 10 10 10 10 10 
11 11 11 11 11 11 11 11 11 11 10 10 10 10 10 10 10 10 10 10 10 10 
12 12 12 12 12 12 12 12 12 12 11 11 11 11 11 11 11 11 11 11 11 11 
13 13 13 13 13 13 13 13 13 13 12 12 12 12 12 12 12 12 12 12 12 12 
14 14 14 14 14 14 14 14 14 14 13 13 13 13 13 13 13 13 13 13 13 13 
15 15 15 15 15 15 15 15 15 15 14 14 14 14 14 14 14 14 14 14 14 14 
16 16 16 16 16 16 16 16 16 16 15 15 15 15 15 15 15 15 15 15 15 15 
17 17 17 17 17 17 17 17 17 17 16 16 16 16 16 16 16 16 16 16 16 16 
18 18 18 18 18 18 18 18 18 18 17 17 17 17 17 17 17 17 17 17 17 17 

Note: Education adjustment applying the following formula: NSSAE = NSSA – (β × [Education(years) – 12]), where β = −0.06256.

Table 20.

Tower of LondonDX: Total execution time score

NSSA Education (years)
 
10 11 12 13 14 15 16 17 18 19 20 
10 10 10 10 10 10 
10 11 11 11 11 11 11 10 10 10 10 10 10 10 
11 12 12 12 12 12 12 11 11 11 11 11 11 11 10 10 10 10 10 10 
12 13 13 13 13 13 13 12 12 12 12 12 12 12 11 11 11 11 11 11 10 10 
13 14 14 14 14 14 14 13 13 13 13 13 13 13 12 12 12 12 12 12 11 11 
14 15 15 15 15 15 15 14 14 14 14 14 14 14 13 13 13 13 13 13 12 12 
15 16 16 16 16 16 16 15 15 15 15 15 15 15 14 14 14 14 14 14 13 13 
16 17 17 17 17 17 17 16 16 16 16 16 16 16 15 15 15 15 15 15 14 14 
17 18 18 18 18 18 18 17 17 17 17 17 17 17 16 16 16 16 16 16 15 15 
18 19 19 19 19 19 19 18 18 18 18 18 18 18 17 17 17 17 17 17 16 16 
NSSA Education (years)
 
10 11 12 13 14 15 16 17 18 19 20 
10 10 10 10 10 10 
10 11 11 11 11 11 11 10 10 10 10 10 10 10 
11 12 12 12 12 12 12 11 11 11 11 11 11 11 10 10 10 10 10 10 
12 13 13 13 13 13 13 12 12 12 12 12 12 12 11 11 11 11 11 11 10 10 
13 14 14 14 14 14 14 13 13 13 13 13 13 13 12 12 12 12 12 12 11 11 
14 15 15 15 15 15 15 14 14 14 14 14 14 14 13 13 13 13 13 13 12 12 
15 16 16 16 16 16 16 15 15 15 15 15 15 15 14 14 14 14 14 14 13 13 
16 17 17 17 17 17 17 16 16 16 16 16 16 16 15 15 15 15 15 15 14 14 
17 18 18 18 18 18 18 17 17 17 17 17 17 17 16 16 16 16 16 16 15 15 
18 19 19 19 19 19 19 18 18 18 18 18 18 18 17 17 17 17 17 17 16 16 

Note: Education adjustment applying the following formula: NSSA&E = NSSA – (β × [Education(years) – 12]), where β = 0.15080.

Table 21.

Tower of LondonDX: Total problem-solving time score

NSSA Education (years)
 
10 11 12 13 14 15 16 17 18 19 20 
10 10 10 10 
10 11 11 11 11 10 10 10 10 10 10 10 10 10 
11 12 12 12 12 11 11 11 11 11 11 11 11 11 10 10 10 10 10 10 10 10 
12 13 13 13 13 12 12 12 12 12 12 12 12 12 11 11 11 11 11 11 11 11 
13 14 14 14 14 13 13 13 13 13 13 13 13 13 12 12 12 12 12 12 12 12 
14 15 15 15 15 14 14 14 14 14 14 14 14 14 13 13 13 13 13 13 13 13 
15 16 16 16 16 15 15 15 15 15 15 15 15 15 14 14 14 14 14 14 14 14 
16 17 17 17 17 16 16 16 16 16 16 16 16 16 15 15 15 15 15 15 15 15 
17 18 18 18 18 17 17 17 17 17 17 17 17 17 16 16 16 16 16 16 16 16 
18 19 19 19 19 18 18 18 18 18 18 18 18 18 17 17 17 17 17 17 17 17 
NSSA Education (years)
 
10 11 12 13 14 15 16 17 18 19 20 
10 10 10 10 
10 11 11 11 11 10 10 10 10 10 10 10 10 10 
11 12 12 12 12 11 11 11 11 11 11 11 11 11 10 10 10 10 10 10 10 10 
12 13 13 13 13 12 12 12 12 12 12 12 12 12 11 11 11 11 11 11 11 11 
13 14 14 14 14 13 13 13 13 13 13 13 13 13 12 12 12 12 12 12 12 12 
14 15 15 15 15 14 14 14 14 14 14 14 14 14 13 13 13 13 13 13 13 13 
15 16 16 16 16 15 15 15 15 15 15 15 15 15 14 14 14 14 14 14 14 14 
16 17 17 17 17 16 16 16 16 16 16 16 16 16 15 15 15 15 15 15 15 15 
17 18 18 18 18 17 17 17 17 17 17 17 17 17 16 16 16 16 16 16 16 16 
18 19 19 19 19 18 18 18 18 18 18 18 18 18 17 17 17 17 17 17 17 17 

Note: Education adjustment applying the following formula: NSSA&E = NSSA – (β × [Education(years) – 12]), where β = 0.11423.

To use the tables, select the appropriate column corresponding to the patient's years of education, find the patient's NSSA, and subsequently refer to the corresponding NSSA&E. When these formulas were applied to the NEURONORMA sample, the shared variances between demographically adjusted NEURONORMA scaled scores and years of education fell to <1%.

Discussion

The objective of this paper was to provide normative data for older Spaniards on the SWCT and the TOLDX. The normative data presented here were obtained from the same study samples as all the other NEURONORMA tests. This is a co-norming study that follows the basic model of the MOANS project.

Stroop Color-Word Interference Test

The pattern of the socio-demographic effects obtained in our study is similar in part to the most normative data published by others. That is to say, the impact of age and education has been clearly found in the three conditions of the test, producing a slowing in color naming and a clear increase in the interference task (e.g., Anstey et al., 2000; Cohn et al., 1984; Graf et al., 1995; Ivnik et al., 1996; Lucas et al., 2005; Moering et al., 2004; Troyer et al., 2006; Van der Elst et al., 2006). Moreover, as other investigations reported earlier (Anstey et al., 2000; Ivnik et al., 1996), we have not found a significant influence of sex on the performance in all the conditions of SCWT. Our results are very similar to that obtained by Ivnik and colleagues (1996) and Lucas and colleagues (2005) in MOANS and MOAANS projects. Owing to sample characteristics, methodological, and statistical differences it is difficult to compare present data with previous studies on Spanish speaking subjects cited in the introduction section.

Tower of London-Drexel University version

In our study, age and education influenced performance in most variables of the TOLDX (Table 2). Sex did not have a significant impact on the scores of the test. Our study includes considerably more subjects in the older age range than the normative sample presented in the technical manual of the TOLDX (Culbertson & Zillmer, 2001). However, it is relevant that when comparing the central tendency (scaled score 100 for 49–59 and 60+ year old subjects) of the norms presented in the manual with our data (NSSA of 10), similar results were obtained. A total correct RS of 3–4 (corresponding to an NSSA of 10) is observed in all NEURONORMA mid-point groups (Tables 4–12) and roughly corresponds to a scaled score of 100 in the American norms. When education adjustments are applied to total moves score NSSA, the final NSSA&E could be 8–9 for higher (13–20 years) educated subjects and 11 for the lower (0–5 years) educated subjects. For subjects with an intermediate education (6–12 years), NSSA&E remains the same (10). Total move scores of the American norms are also similar to ours. In the American norms, a scaled score of 100 corresponds to an RS of 30–32 for 40–59-year-old subjects and to an RS of 39–40 for 60+-year-old subjects. Similarly, in the NEURONORMA project, an RS of 30–32 corresponds to an NSSA of 10–11, and an RS of 39–40 corresponds to an NSSA of 9–10. Time scores (initiation time, total execution time, and total problem-solving time) show the same similar pattern of central tendencies. In our study, education allows a further adjustment of age-corrected RS.

Considering that the TOLDX depends on various processes such as perceptual, conceptual, working memory, or executive (Newman et al., 2003), the interpretation of abnormal scores should be carried out with caution. Future NEURONORMA studies should focus on the correlations of the variables of the SCWT and the TOLDX with other tests of the project, especially with working memory measures (Zook et al., 2004).

General Discussion

To help clinicians, NSSA were adjusted to NSSA&E using tables resulting from the application of computational formulas. In these tables, figures were rounded to an integer. In some cases, the resulting adjustment may be placed beyond the defined scaled score ranges (e.g., 21 or −1). In these extreme cases, the final score should be 18 or 2, respectively. It would not be accurate to apply these computational formulas to younger individuals due to the different impact of the demographic variables on the cognitive performance across the life span (e.g., Lucas et al., 2005).

The validity of these normative data is related to the similarity between the characteristics of the specifically studied subject and the demographic features of the normative sample. Present norms provide a useful resource for clinical studies in a Spanish population. The general limitations of NEURONORMA norms have been discussed in a previous paper (Peña-Casanova et al., 2009) and are mainly related to the selection of the participants (limited representation of extremely elderly participants and a convenience sample of community volunteers). Despite these limitations, this paper presents the largest normative study to date for neuropsychological performance in older Spanish subjects on the SWCT and on the TOLDX.

Funding

This study was mainly supported by a grant from the Pfizer Foundation, and by the Medical Department of Pfizer, SA, Spain. It was also supported by the Behavioral Neurology group of the Program of Neuropsychopharmacology of the Institut Municipal d'Investigació Mèdica, Barcelona, Spain. Dr. Jordi Peña-Casanova has received an intensification research grant from the CIBERNED (Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas), Instituto Carlos III (Ministry of Health & Consumer Affairs of Spain). No conflicts of interest affect this manuscript.

Conflict of Interest

None declared.

Appendix

Members of the NEURONORMA.ES Study Team

Steering committee: JP-C, Hospital del Mar, Barcelona, Spain; RB, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain; MA, Hospital Mútua de Terrassa, Terrassa, Spain.

Principal Investigators: JP-C, Hospital de Mar, Barcelona, Spain; RB, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain; MA, Hospital Mútua de Terrassa, Terrassa, Spain; JLM, Hospital Clínic, Barcelona, Spain; AR, Hospital Clínico Universitario, Santiago de Compostela, Spain; MSB (deceased), Hospital Clínico San Carlos, Madrid, Spain; CA, Hospital Virgen Arrixaca, Murcia, Spain; CM-P, Hospital Virgen Macarena, Sevilla, Spain; AF-G, Hospital Universitario La Paz, Madrid, Spain; MF, Hospital de Cruces, Bilbao, Spain.

Genetics sub-study: Rafael Oliva, Service of Genetics, Hospital Clínic, Barcelona, Spain.

Neuroimaging sub-study: Beatriz Gómez-Ansón, Radiology Department and IDIBAPS, Hospital Clínic, Barcelona, Spain. Research Fellows: Gemma Monte, Elena Alayrach, Aitor Sainz and Claudia Caprile, Fundació Clinic, Hospital Clinic, Barcelona, Spain; Gonzalo Sánchez, Behavioral Neurology Group, Institut Municipal d'Investigació Mèdica, Barcelona, Spain.

Clinicians, Psychologists and Neuropsychologists: NG-F, (coordinator), Peter Böhm, Sonia González, Yolanda Buriel, MQ, SQ-U, Gonzalo Sánchez, Rosa M. Manero, Gracia Cucurella, Institut Municipal d'Investigació Mèdica, Barcelona, Spain; Eva Ruiz, MS, Laura Torner, Hospital Clínic, Barcelona, Spain; Dolors Badenes, Laura Casas, Noemí Cerulla, Silvia Ramos, Loli Cabello, Hospital Mútua de Terrassa, Terrassa, Spain; Dolores Rodríguez, Clinical Psychology and Psychobiology Dept. University of Santiago de Compostela, Spain; MP, Clara Villanueva, Hospital Clínico San Carlos, Madrid, Spain; Rafael Carles, Judit Jiménez, Martirio Antequera, Hospital Virgen Arixaca, Murcia, Spain; Jose Manuel Gata, Pablo Duque, Laura Jiménez, Hospital Virgen Macarena, Sevilla, Spain; Azucena Sanz, María Dolores Aguilar, Hospital Universitario La Paz, Madrid, Spain; Ana Molano, Maitena Lasa, Hospital de Cruces, Bilbao, Spain.

Data management and Biometrics: JMS, Francisco Hernández, Irune Quevedo, Anna Salvà, VA, European Biometrics Institute, Barcelona, Spain.

Administrative Management: Carme Pla (deceased), Romina Ribas, Department of Psychiatry and Forensic Medicine, Universitat Autònoma de Barcelona, and Behavioral Neurology Group, Institut Municipal d'Investigació Mèdica, Barcelona, Spain.

English Edition: Stephanie Lonsdale, Program of Neuropsychopharmacology, Institut Municipal d'Investigació Mèdica, Barcelona, Spain.

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Author notes

Deceased.
The members of the NEURONORMA.ES Study Team are listed in the Appendix.