From: Assessing general cognitive and adaptive abilities in adults with Down syndrome: a systematic review
Study | IQ test | Score type(s) provided | Participants | Participant ages | Raw scores | Standardised scores | Floor effects |
---|---|---|---|---|---|---|---|
Tests not specifically designed for children and adolescents (most recent first) | |||||||
Lao et al., [26] | PPVT-IV | Standardised score and age-equivalent score | 52 | 37.3 (6.6; 30–50) | NR | 56.6 (17.2) standardised score; 8.19 (3.44) age-equivalent score | NR |
Hartley et al. [14]* | PPVT-IV | Age-equivalent score | 58 | 37.6 (6.8; ≥ 30) | NR | 8.10 (3.34) | NR |
Tomaszewski et al. [15] | Stanford Binet 5th Ed | Full IQ score | 31 | 25.9 (5.92) | NR | 46.6 (9.1) | NR |
Sinai et al. [11] | KBIT-2 | Raw scores for verbal and non-verbal subscales | 30 no dementia | 50.9 (4.83) | Total, 23.17 (19.50; 3–63); Verbal, 16.37 (13.33; 1–47); Non-verbal, 6.8 (6.92; 0–15) | NR | Verbal, 0%; Non-verbal, 16.7% |
19 diagnosed or possible dementia | 55.6 (6.77) | Total, 9.74 (11.06; 1–49); Verbal, 6.53 (7.16; 0–34); Non-verbal, 3.21 (4.16; 0–20) | NR | Verbal, 5.3%; Non-verbal, 21.1% | |||
Startin et al. [16] | KBIT-2 | Raw scores for verbal and non-verbal subscales; full IQ scores floor effects only | 130 aged 36+ years without dementia | 47.77 (7.01; 36–71) | Verbal, 30.55 (17.47; 2–80); Non-verbal, 12.55 (6.57; 0–32); | NR | Verbal raw, 0%; Verbal IQ, 66.7%; Non-verbal raw, 6.7%; Non-verbal IQ, 39.4% |
51 aged 36+ years with dementia | 54.20 (6.95; 38–67) | Verbal, 18.68 (13.77; 1–51); Non-verbal, 8.29 (6.45; 0–19) | NR | Verbal raw, 0%; Verbal IQ, 84.0%; Non-verbal raw, 16.7%; Non-verbal IQ, 62.5% | |||
124 aged 16–35 years | 25.24 (5.53; 16–35) | Verbal, 35.03 (16.77; 2–82); Non-verbal, 14.98 (6.9; 0–32) | NR | Verbal raw, 0%; Verbal IQ, 50.8%; Non-verbal raw, 4.1%; Non-verbal IQ, 33.9% | |||
de Sola et al. [17] | KBIT (Spanish version) | Full IQ score; combined verbal and non-verbal standardised KBIT score | 86 | 23.3 (4.3; 16–34) | NR | Full IQ median, 41; Standardised KBIT score, 105 (17.8; 80–180) | 41.9% |
Ghezzo et al. [8] | WAIS-R | Full IQ score; verbal IQ score; performance IQ score | 36 adults with DS (of a larger sample of 67 participants which included children) | 18–29 years.: n = 24, 22.34 (3.40) 30–39 years.: n = 17, 34.27 (3.04) ≥ 40: years. n = 18, 49.34 (6.91) | NR | Total IQ 18–29 years., 49.71 (12.69) 30–39 years., 48.80 (11.84) ≥ 40, 33.20 (19.60) Verbal IQ 18–29 years., 53.43 (13.02) 30–39 years., 51.60 (12.91) ≥40, 33.60 (20.02) Performance IQ 18–29 years., 51.38 (12.49) 30–39 years., 52.90 (12.44) ≥40, 36.20 (23.72) | NR |
Breia et al. [18] | WAIS-III (Portuguese version) | Full IQ score; verbal IQ score; non-verbal IQ score | 26 (of a larger sample of 209) | Full sample, 32.6 (8.58) | NR | Full scale IQ, 49.65 (4.93; 45–61); Verbal IQ, 52.27 (5.65; 45–64); Non-verbal IQ, 50.77 (5.06; 45–62) | NR |
Iacono et al. [13] | PPVT-III | Age-equivalent score | 55 | 38 (19–58) | NR | 5.17 (2.17; 1.67–9.75) | NR |
RCPM | Raw score | 55 | 38 (19–58) | 10.65 (3.95; 4–20) | NR | NR | |
Kay et al. [19] | PCFT | Raw scores | 85 | 38.2 | 88.0 (61.9; 0–224) Median 97 | NR | NR |
Patel et al. [20] | Five subtests from the early-development battery of the WJTCA-R | Raw scores | 82 females (58 pre-menopausal, 24 post-menopausal), 80 males | Total range 21–57; premenopausal females 34.7 (6.8), postmenopausal females 49.7 (4.2) | Pre-menopausal females, 468.7 (15.9); age-matched males, 462.2 (17.7) Post-menopausal females; 446.2 (19.0 SD); age-matched males, 453.1 (23.3 SD) | NR | NR |
Tests designed for children and adolescents (most recent first) | |||||||
de Knegt et al. [21] | WPPSI-R | Age-equivalent score | 244 | 38.1 (11.1) | NR | 5.0 (1.5) | NR |
d’Ardhuy et al. [10] | Leiter-R (full) | Non-verbal IQ score | 41 | 22.7 (3.4; 18–30) | 39.0 (6.0; 36–65) | 61% | |
Dressler et al. [22] | RCPM** or Leiter-R | Age-equivalent score | 49 | 28.8 (8.4; 19–52) | NR | 4.72 (2.46; 3.06–10.0) | NR |
Strydom et al. [23] | BPVS-II | Raw and age-equivalent score | 32 (10 mild ID, 18 moderate ID, 4 severe ID) | 32.59 (6.78; 18–45) | 67.8 (22.89; 14–112) | Mild ID, 7.8; Moderate ID, 4.7; Severe ID, 2.04; Overall range 2.04–12.01 | 3 individuals could not complete the test |
Glenn and Cunningham [12] | BPVS-II | Age-equivalent score | 46 | 19.83 (1.92; 16.17–24.33) | NR | 6.53 (1.98) | NR |
Leiter-R (brief) | Non-verbal IQ; age-equivalent score | 46 | 19.83 (1.92; 16.17–24.33) | NR | Non-verbal IQ, 3.3 (0.5); Age-equivalent, 5.2 (1.0) | Majority of IQ scores were 36, with very few over 45, despite age-equivalent scores differing | |
Kittler et al. [24]* | WISC-R | Raw scores | 42 (21 females, 21 males) | Female, 37.9 (5.9) Male, 40.3 (5.7) | Verbal subtests: Information: F 6.6 (3.7), M 7.2 (4.0) Similarities: F 4.0 (5.3), M 3.2 (4.5) Arithmetic: F 3.1 (2.0), M 2.7 (1.8) Vocabulary: F 13.9 (7.2), M 17.3 (9.1) Comprehension: F 6.7 (4.7), M 7.4 (5.0) Non-verbal subtests: Picture completion: F 7.8 (5.3), M 8.6 (4.4) Picture arrangement: F 4.4 (5.1), M 2.6 (3.6) Block design: F 9.6 (7.3), M 8.0 (6.0) Object assembly: F 11.7 (6.1), M 8.7 (5.8) Coding: F 22.0 (10.5), M 15.7 (9.6) | NR | 40% scored 0 or 1 on Picture Arrangement; 48% scored 0 or 1 on Similarities |
Devenny et al. [25]* | WISC-R | Subtest raw scores | 44 | 46.85 (6.01) | Information, 6.64 (3.71); Arithmetic, 3.00 (2.03); Vocabulary, 15.59 (7.83); Comprehension, 7.17 (5.14); Picture completion, 7.67 (4.69); Block design, 8.82 (6.90); Object assembly, 9.68 (6.17); Coding, 18.33 (10.82); Digit span, 2.98 (2.25) | NR | 52% scored 0 or 1 on Picture Arrangement; 66% scored 0 or 1 on Similarities |
Das et al. [7] | PPVT-R** | Raw score | 16 younger | 43.7 (2.9; 40–49) | 57.75 (21.16) | NR | NR |
16 older | 55.2 (3.9; 50–62) | 43.00 (40.98) | NR | NR | |||
MAT | Raw score | 16 younger | 43.7 (2.9; 40–49) | 6.25 (4.67) | NR | “Too difficult for most participants” | |
16 older | 55.2 (3.9; 50–62) | 3.75 (3.51) | NR |