Table 3.
Changes in test scores between baseline and 4- or 5-year follow-up, by treatment group [adjusted coefficient ± SE (n)].
|
p-Value
|
||||
|---|---|---|---|---|
| Test score | Amalgam | Composite | Intention-to-treata | Kolmogorov-Smirnov Test |
| WISC-III | ||||
| Factor | ||||
| Verbal Comprehension | 2.2 ± 0.6 (219) | 1.5 ± 0.6 (217) | 0.46 | 0.69 |
| Perceptual Organization | 3.6 ± 0.7 (219) | 3.1 ± 0.7 (216) | 0.58 | 0.72 |
| Freedom from Distractibility | 3.9 ± 0.7 (219) | 2.4 ± 0.7 (216) | 0.57 | 0.71 |
| Processing Speed | 7.2 ± 0.9 (216) | 5.1 ± 0.9 (217) | 0.08 | 0.09 |
| Subtest | ||||
| Verbal | ||||
| Information | 0.3 ± 0.2 (219) | 0.4 ± 0.2 (217) | 0.61 | 0.97 |
| Similarities | 0.8 ± 0.1 (219) | 0.7 ± 0.2 (217) | 0.56 | 1.00 |
| Vocabulary | 0.4 ± 0.1 (219) | 0.2 ± 0.1 (217) | 0.26 | 0.41 |
| Comprehension | 0.2 ± 0.2 (219) | −0.1 ± 0.2 (217) | 0.22 | 0.98 |
| Digit Span | 0.7 ± 0.2 (219) | 0.5 ± 0.2 (216) | 0.26 | 1.00 |
| Performance | ||||
| Picture Completion | 1.2 ± 0.2 (219) | 1.2 ± 0.2 (217) | 0.84 | 0.57 |
| Coding | 0.2 ± 0.2 (218) | −0.1 ± 0.2 (217) | 0.19 | 0.81 |
| Picture Arrangement | 0.5 ± 0.2 (219) | 0.6 ± 0.2 (216) | 0.79 | 0.77 |
| Block Design | 0.3 ± 0.2 (219) | 0.1 ± 0.2 (217) | 0.43 | 0.63 |
| Object Assembly | 0.3 ± 0.2 (219) | 0.3 ± 0.2 (216) | 0.96 | 0.99 |
| Symbol Search | 2.5 ± 0.2 (216) | 2.2 ± 0.2 (217) | 0.21 | 0.73 |
| Mazes | 0.8 ± 0.2 (218) | 0.7 ± 0.2 (217) | 0.85 | 0.79 |
| WIAT | ||||
| Composite | ||||
| Reading | −1.0 ± 0.7 (217) | −1.7 ± 0.7 (215) | 0.44 | 0.34 |
| Mathematics | −1.9 ± 0.7 (216) | −3.0 ± 0.8 (207) | 0.33 | 0.57 |
| Scale | ||||
| Basic Reading | −0.6 ± 0.6 (219) | −1.3 ± 0.6 (216) | 0.37 | 0.53 |
| Reading Comprehension | 0.7 ± 0.7 (217) | 0.2 ± 0.7 (215) | 0.70 | 0.26 |
| Numerical Operations | −5.2 ± 0.8 (216) | −6.7 ± 0.9 (207) | 0.20 | 0.72 |
| Math Reasoning | 1.5 ± 0.7 (219) | 1.3 ± 0.7 (216) | 0.85 | 1.00 |
| Spelling | −1.7 ± 0.7 (219) | −3.1 ± 0.7 (215) | 0.14 | 0.81 |
| Listening Comprehension | −5.5 ± 0.7 (212) | −4.5 ± 0.7 (205) | 0.27 | 0.63 |
| WRAML | ||||
| Index | ||||
| Verbal Memory | 2.9 ± 0.6 (212) | 2.2 ± 0.6 (202) | 0.47 | 0.57 |
| Visual Memory | 6.3 ± 0.8 (212) | 5.0 ± 0.8 (204) | 0.23 | 0.42 |
| Learning | 10.2 ± 0.8 (212) | 10.3 ± 0.8 (203) | 0.91 | 0.28 |
| Scale | ||||
| Picture Memory | 0.8 ± 2.2 (212) | 0.6 ± 0.2 (204) | 0.28 | 0.98 |
| Design Memory | 1.0 ± 0.2 (212) | 1.2 ± 0.2 (204) | 0.53 | 0.95 |
| Story Memory | 0.7 ± 0.2 (212) | 0.9 ± 0.2 (203) | 0.46 | 0.96 |
| Verbal learning | 1.4 ± 0.2 (212) | 1.4 ± 0.2 (203) | 0.92 | 0.84 |
| Finger Windows | 0.8 ± 0.2 (212) | 0.4 ± 0.2 (204) | 0.09 | 0.05 |
| Sound Symbol | 2.8 ± 0.2 (212) | 2.7 ± 0.2 (203) | 0.55 | 0.12 |
| Sentence Memory | 0.3 ± 0.1 (212) | 0.3 ± 0.1 (204) | 0.80 | 0.56 |
| Visual Learning | 0.4 ± 0.2 (212) | 0.6 ± 0.2 (203) | 0.29 | 0.82 |
| Number–Letter Memory | 0.3 ± 0.1 (212) | −0.3 ± 0.1 (203) | 0.002 | 0.04 |
| WRAVMA | ||||
| Drawing | −3.8 ± 0.9 (211) | −3.1 ± 0.9 (203) | 0.63 | 0.78 |
| Matching | 3.0 ± 0.8 (211) | 3.5 ± 0.8 (203) | 0.62 | 0.96 |
| Pegboard | 9.3 ± 0.9 (211) | 8.4 ± 1.0 (203) | 0.50 | 0.82 |
| Trail-Making Test | ||||
| Part A: time to complete | −15.5 ± 0.3 (203) | −16.1 ± 0.3 (200) | 0.25 | 0.68 |
| Part A: no. of errors | −0.2 ± 0.03 (203) | −0.1 ± 0.04 (200) | 0.07 | 0.95 |
| Part B: time to complete | −45.6 ± 1.0 (201) | −50.4 ± 1.1 (193) | 0.002 | 0.36 |
| Part B: no. of errors | −0.6 ± 0.1 (201) | −0.7 ± 0.1 (193) | 0.09 | 0.88 |
| Finger Tapping | ||||
| Right hand (mean of 5 trials) | 5.7 ± 0.4 (208) | 5.1 ± 0.4 (202) | 0.28 | 0.42 |
| Left hand (mean of 5 trials) | 6.4 ± 0.3 (208) | 5.7 ± 0.3 (202) | 0.10 | 0.54 |
| Verbal Cancellation | ||||
| Ordered trial: no. of errors | −19.3 ± 0.2 (200) | −19.4 ± 0.2 (198) | 0.57 | 0.59 |
| Unordered trial: no. of errors | −15.0 ± 0.1 (200) | −14.9 ± 0.2 (198) | 0.83 | 0.99 |
| Verbal Fluency | ||||
| Category fluency (sum of 4 trials) | 9.7 ± 0.4 (210) | 9.5 ± 0.4 (201) | 0.70 | 0.91 |
| Letter fluency (sum of 3 trials) | 13.3 ± 0.5 (210) | 12.4 ± 0.6 (201) | 0.25 | 0.77 |
| Reaction Time | ||||
| Mean response time (msec) | −0.1 ± 0.0 (181) | −0.1 ± 0.0 (180) | 0.67 | 0.79 |
| Response time SD | −0.1 ± 0.0 (181) | −0.1 ± 0.0 (180) | 0.74 | 0.91 |
| Stroop Color–Word Interference Test | ||||
| Color | 19.7 ± 0.7 (165) | 18.0 ± 0.7 (164) | 0.09 | 0.17 |
| Word | 26.1 ± 0.8 (165) | 25.0 ± 0.8 (163) | 0.35 | 0.89 |
| Color–Word | 12.8 ± 0.6 (165) | 12.8 ± 0.6 (164) | 0.96 | 0.75 |
| Wisconsin Card Sorting Test | ||||
| No. of categories achieved | 1.1 ± 0.1 (200) | 1.1 ± 0.1 (194) | 0.94 | 0.97 |
| No. of trials to first category | −5.8 ± 0.3 (200) | −5.6 ± 0.3 (194) | 0.69 | 0.96 |
| Total errorsb | 15.6 ± 0.9 (199) | 17.2 ± 1.0 (191) | 0.25 | 0.14 |
| Total perseverative errorsb | 17.6 ± 0.9 (199) | 19.3 ± 1.0 (191) | 0.19 | 0.59 |
| Percent conceptual level responses | 15.7 ± 1.0 (199) | 17.3 ± 1.0 (191) | 0.26 | 0.20 |
a
Adjusted for baseline score, randomization stratum, baseline age, sex, baseline family socioeconomic status, baseline hair mercury concentration, and baseline blood lead concentration.
b
Standard score.