Table 2.
Follow-up results at 5.5 years, born <27 weeks’ GA who reached 5.5 years’ CA in 2018–2020, separately for infants born at 24, 25 and 26 weeks’ gestation
| Total | 24 weeks | 25 weeks | 26 weeks | P value | |
| WPPSI-III-NL, N evaluated | 365 | 70 | 106 | 189 | |
| FSIQ, mean (SD) | 96.2 (14.8)* | 92.4 (16.5) | 95.4 (14.1) | 98.0 (14.2) | 0.020† |
| ≥85 (≥−1 SD) | 79% (75–83) | 71% (59–82) | 80% (71–87) | 82% (75–87) | 0.343‡ |
| 70–84 (−2 to −1 SD) | 17% (13–21) | 21% (13–33) | 15% (9–23) | 16% (11–22) | |
| <70 (<−2 SD) | 4% (2–7) | 7% (2–16) | 5% (2–11) | 3% (1–6) | |
| VIQ, mean (SD) | 99.0 (16.4) | 95.4 (18.1) | 98.5 (15.6) | 100.7 (15.9) | 0.065 |
| ≥85 (≥−1 SD) | 81% (77–85) | 77% (66–86) | 82% (74–89) | 83% (76–88) | 0.095‡ |
| 70–84 (−2 to −1 SD) | 14% (11–18) | 13% (6–23) | 12% (7–20) | 15% (11–21) | |
| <70 (<−2 SD) | 5% (3–7) | 10% (4–20) | 6% (2–12) | 2% (1–5) | |
| PIQ, mean (SD) | 96.4 (13.4)* | 93.1 (13.2) | 96.2 (13.5) | 97.8 (13.2) | 0.036† |
| ≥85 (≥−1 SD) | 83% (79–87) | 76% (65–86) | 82% (74–89) | 86% (81–91) | 0.290‡ |
| 70–84 (−2 to −1 SD) | 15% (12–19) | 21% (12–32) | 16% (10–23) | 13% (9–19) | |
| <70 (<−2 SD) | 1% (0–3) | 3% (0–10%) | 2% (0–7) | 1% (0–3) | |
| PSQ, mean (SD) | 92.0 (15.0)* | 89.3 (17.2) | 91.8 (14.5) | 93.1 (14.4) | 0.186 |
| ≥85 (≥−1 SD) | 70% (65–74) | 63% (51–75) | 74% (64–82) | 70% (63–77) | 0.063‡ |
| 70–84 (−2 to −1 SD) | 25% (20–27) | 27% (17–39) | 19% (12–27) | 27% (21–34) | |
| <70 (<−2 SD) | 5% (3–8) | 10% (4–19) | 8% (3–14) | 3% (1–6) | |
| M-ABC-2-NL, N evaluated | 383 | 70 | 114 | 199 | |
| Total standard score, mean (SD) | 6.7 (3.3)* | 5.8 (3.0) | 6.6 (3.4) | 7.1 (3.3) | 0.024† |
| ≤5 | 41% (36–46) | 55% (43–67) | 41% (32–51) | 36% (30–43) | 0.001‡ |
| Manual skills, mean (SD) | 7.4 (3.1)* | 6.9 (3.1) | 7.4 (3.4) | 7.6 (3.0) | 0.209 |
| ≤5 | 29% (25–34) | 32% (22–44) | 32% (23–41) | 26% (20–33) | 0.506‡ |
| Ball skills, mean (SD) | 8.1 (3.3)* | 7.2 (3.3) | 8.0 (3.3) | 8.4 (3.4) | 0.028† |
| ≤5 | 26% (21–31) | 32% (21–44) | 25% (17–34) | 24% (18–31) | 0.405‡ |
| Balance skills score, mean (SD) | 7.8 (3.5)* | 7.2 (3.5) | 7.2 (3.4) | 7.8 (3.5) | 0.240 |
| ≤5 | 32% (27–37) | 36% (25–48) | 32% (24–42) | 30% (23–37) | 0.588‡ |
| <7 (<−1 SD) | 41% (36–46) | 47% (35–59) | 44% (35–54) | 37% (30–44) | 0.206 |
| Neurological exam | |||||
| Normal | 79% (75–83) | 79% (69–87) | 75% (67–82) | 82% (76–86) | 0.394‡ |
| Mildly abnormal (eg, posture, coordination or tone dysregulation disorders) | 15% (12–19) | 11% (5–19) | 19% (13–26) | 14% (10–19) | |
| CP, GMFCS 1 | 2% (1–4) | 5% (2–12) | 2% (0–6) | 2% (0–4) | |
| CP, GMFCS 2–5 | 3% (2–5) | 5% (2–12) | 3% (1–8) | 2% (1–5) | |
| Vision | |||||
| Normal | 79% (75–82) | 71% (60–79) | 81% (73–87) | 81% (75–85) | 0.101‡ |
| Mild visual problems including squints or refractive errors | 18% (15–22) | 23% (15–33) | 16% (10–23) | 18% (13–23) | |
| Functionally impaired vision or blindness | 3% (2–5) | 6% (2–13) | 3% (1–8) | 2% (0–4) | |
| Hearing | |||||
| Normal | 94% (91–96) | 96% (90–99) | 94% (89–98) | 92% (88–95) | 0.262‡ |
| Mild hearing loss, not sufficient to require aids | 5% (4–8) | 2% (0–7) | 6%(2–11) | 7% (4–10) | |
| Hearing loss requiring aids or severe sensorineural hearing loss despite aids | 1% (0–2) | 2% (0–7) | 0% (0–3) | 1% (0–4) |
Results are presented as mean (SD) or as proportion (95% CI). Dutch version of the WPPSI-III-NL was available for 365 subjects. Dutch version of the M-ABC-2-NL was available for 383 subjects. Information on neurological exam, vision and hearing was available for 484 subjects (24 weeks, n=95, 25 weeks n=145 and 26 weeks n=244). The p value reflects differences between 24, 25 and 26 weeks’ gestation.
*Significantly lower compared with the normative mean, all p<0.001.
†P value is the result of a one-way analysis of variance applied on all three GA groups.
‡P value is the result of a χ2 test applied on all three categorical rows of the score. P<0.05 is considered significant.
CA, corrected age; CP, cerebral palsy; FSIQ, full-scale IQ; GA, gestational age; GMFCS, Gross Motor Function Classification System; M-ABC-2-NL, Movement Assessment Battery for Children; PIQ, performance composite score; PSQ, processing speeds composite score; VIQ, verbal composite score; WPPSI-III-NL, Wechsler Preschool and Primary Scale of Intelligence Scale-III.