Table 2.
Descriptive statistics (means, standard deviations, and P-values) for standardized Bayley cognitive scores, PLS-4, and CDI language assessments at 12 and 18 months of age.
| Measure | PEx12 | NC12 | P-value | PEx18 | NC18 | P-value |
|---|---|---|---|---|---|---|
| BAY-CCS | 106.1 (8.9) | 110.9 (9.8) | 0.108 | 107.1 (11.7) | 100.2 (9.7) | 0.057 |
| PLS-EXS | 106.7 (8.2) | 105.1 (7.4) | 0.521 | 103.4 (10.7) | 104.3 (7.6) | 0.759 |
| PLS-RCS | 96.9 (10.8) | 94.8 (10.6) | 0.541 | 103.9 (11.1) | 97.3 (12.7) | 0.099 |
| CDI-TGR | 25.6 (12) | 24.3 (11) | 0.997 | |||
| CDI-WUR | 105.2 (94) | 65.17 (51) | 0.999 | |||
| CDI-WPR | 8.05 (8.4) | 5.83 (7.4) | 1.000 | 128.7 (114) | 78.95 (95) | 0.995 |
Notes: PEx12, passive exposure group at 12 months; NC12, 12-months naïve control group; PEx18, passive exposure group at 18 months; NC18, 18-months naïve control group; BAY-CCS, Bayley Cognitive Composite Score; PLS, The Preschool Language Scale-4th ed; PLS-EXS, PLS-4 Expressive standard score; PLS-RCS, PLS-4 Receptive standard score; CDI, MacArthur-Bates Communicative Development Inventory; CDI-TGR, # of total gestures raw score at 12 months; CDI-WUR, # of words understood raw score at 12 months; CDI-WPR, # Words Produced raw score at 12 and 18 months. Note that raw scores were converted to z-scores for statistical analyses.