A solution to limitations of cognitive testing in children with intellectual disabilities: the case of fragile X syndrome
A solution to limitations of cognitive testing in children with intellectual disabilities: the case of fragile X syndrome
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DOI：
10.1007/s11689-008-9001-8
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发表时间：
2009-03-01
影响因子：
4.9
通讯作者：
Hall, Scott
中科院分区：
文献类型：
--
作者：
Hessl, David;Nguyen, Danh V.;Hall, Scott
智力残疾儿童的智力测验有很大的局限性。广泛使用的智力测验，如韦氏智力量表的规范样本，很少包括足够数量的被试ID需要提供敏感的测量在非常低的能力范围，他们是高度受地板效应。这些儿童的智商测量问题阻碍了对强项和弱项的表征，在研究应用和临床环境中对认知能力的估计较差，评估、预后估计和计划干预的效用有限。在这里，我们研究了敏感性的韦氏儿童智力量表（WISC-III）在一个大样本的儿童脆性X综合征（FXS），最常见的原因遗传性ID。WISC-III管理到217名儿童FXS（年龄6-17岁，83名女孩和134名男孩）。使用从Psychological Corporation获得的原始规范数据，我们使用z分数转换计算了代表每个参与者与标准化样本的实际偏差的归一化分数。为了验证这种方法，我们比较了新的标准化分数与通常的标准分数之间的相关性，其中包括适应性行为的测量（Vineland适应性行为量表）和特定于FXS的遗传测量（FMR 1蛋白或FMRP）。WISC-III标准分的分布在很大比例的参与者中显示出显著的地板效应，尤其是男性（64.9%-94.0%）。通过z分数归一化，消除了地板问题，分数呈正态分布。此外，我们发现认知表现和适应行为之间的相关性，以及认知和FMRP之间的相关性，当使用这些标准化分数时，与通常的标准化分数相比，这些分数得到了很大的改善。这项研究的结果表明，有意义的变化，在智力与FXS的儿童，并可能与神经发育障碍的儿童的其他人群，是模糊的原始分数到标准化分数的通常翻译。原始分数转换的方法可以改善ID人群中认知功能的表征，特别是对于研究应用。
Intelligence testing in children with intellectual disabilities (ID) has significant limitations. The normative samples of widely used intelligence tests, such as the Wechsler Intelligence Scales, rarely include an adequate number of subjects with ID needed to provide sensitive measurement in the very low ability range, and they are highly subject to floor effects. The IQ measurement problems in these children prevent characterization of strengths and weaknesses, poorer estimates of cognitive abilities in research applications, and in clinical settings, limited utility for assessment, prognosis estimation, and planning intervention. Here, we examined the sensitivity of the Wechsler Intelligence Scale for Children (WISC-III) in a large sample of children with fragile X syndrome (FXS), the most common cause of inherited ID. The WISC-III was administered to 217 children with FXS (age 6-17 years, 83 girls and 134 boys). Using raw norms data obtained with permission from the Psychological Corporation, we calculated normalized scores representing each participant's actual deviation from the standardization sample using a z-score transformation. To validate this approach, we compared correlations between the new normalized scores versus the usual standard scores with a measure of adaptive behavior (Vineland Adaptive Behavior Scales) and with a genetic measure specific to FXS (FMR1 protein or FMRP). The distribution of WISC-III standard scores showed significant skewing with floor effects in a high proportion of participants, especially males (64.9%-94.0% across subtests). With the z-score normalization, the flooring problems were eliminated and scores were normally distributed. Furthermore, we found correlations between cognitive performance and adaptive behavior, and between cognition and FMRP that were very much improved when using these normalized scores in contrast to the usual standardized scores. The results of this study show that meaningful variation in intellectual ability in children with FXS, and probably other populations of children with neurodevelopmental disorders, is obscured by the usual translation of raw scores into standardized scores. A method of raw score transformation may improve the characterization of cognitive functioning in ID populations, especially for research applications.