Mean full-scale intelligence quotient in children with sickle cell disease
| Test Instrument | Patient Score | No. | Control Score | No. | Reference |
|---|---|---|---|---|---|
| WISC-R | 88.8 | 126 | Armstrong et al., 1996 | ||
| 77.7 | 21 | 94.3 | 21 | Swift et al., 1989 | |
| 82.7 | 43 | 88.0 | 30 | Wasserman et al., 1991 | |
| 72.3 | 28 | 73.5 | 19 | Knight et al., 1995 | |
| 85.7 | 31 | 92.0 | 31 | Noll et al., 2001 | |
| 85.4 | 15 | Present study | |||
| WISC-III | 82.8 | 165 | Wang et al., 2001 | ||
| 83.9 | 156 | 90.3 | 76 | Bernaudin et al., 2000 | |
| 81.8 | 41 | Brown et al., 2000 | |||
| 86.0 | 30 | 92.1 | 15 | Watkins et al., 1998 | |
| 78.0 | 34 | Present study | |||
| Weighted mean | 83.6 | 89.1 |
Note.—Mean full-scale intelligence quotient for 690 patients with sickle cell disease, as compared with 192 control participants. Data are from testing of patients and age- and race-similar control participants with the WISC-R or WISC-III. The weighted mean is an average of data from all studies, weighted for the number of study participants in each of the studies. If a conservative assumption is made that the SD of patient and control scores is ± 15, as in Wechsler normative data, then the difference in weighted mean between patients and control participants is significant (P < .000003). To be even more conservative, we then excluded studies that did not include control data collected concurrent with patient data or that derived control data from non-siblings, and we assumed that the sample size of patients was equivalent to the sample size of control participants. This left four studies (underlined), with a sample size of 142 patients and 142 control participants; the full-scale intelligence quotient difference between patients and control participants was still significant (P < .00001).