Mazzocco Michèle M M
Math Skills Development Project, Kennedy Krieger Institute, and Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21211, USA.
Dev Disabil Res Rev. 2009;15(1):35-44. doi: 10.1002/ddrr.50.
Turner syndrome is a common disorder with a prevalence of 1:2,500 live female births. Although not associated with mental retardation, there is an increased risk of learning difficulties in this population. In particular, mathematical learning difficulties among girls with Turner syndrome are prevalent, significant, and persistent. As such, the study of mathematical performance in girls with Turner syndrome presents opportunities to advance our knowledge of mathematics ability, disability, and disability subtypes. Moreover, the Turner syndrome phenotype illustrates the challenges faced when defining mathematical learning disability (MLD) and characterizing MLD subtypes because the cognitive phenotype is aligned with several proposed MLD subtypes. There is some evidence linking MLD in Turner syndrome with spatial deficits, with executive dysfunction, and with deficient numerosity skills. Yet there is also conflicting evidence as to whether any of these explanations underlies MLD in Turner syndrome. Most mathematical difficulties in girls with Turner syndrome, as a group, occur on timed tests or on complex problems. On untimed tests, achievement test scores may be age appropriate. Therefore, the inclusion of MLD in the Turner syndrome cognitive phenotype reminds us that we cannot rule out MLD solely on the basis of performance on an untimed calculations subtest, and it poses a challenge to the widespread practice in which many researchers engage, that is, defining MLD on the basis of broad mathematics achievement test outcomes.
特纳综合征是一种常见疾病，在活产女婴中的患病率为1:2500。虽然它与智力发育迟缓无关，但该人群出现学习困难的风险增加。特别是，特纳综合征女孩中数学学习困难很普遍、严重且持续存在。因此，对特纳综合征女孩数学表现的研究为增进我们对数学能力、残疾及残疾亚型的了解提供了机会。此外，特纳综合征的表型说明了在定义数学学习障碍（MLD）和刻画MLD亚型时所面临的挑战，因为其认知表型与几种提出的MLD亚型相符。有一些证据将特纳综合征中的MLD与空间缺陷、执行功能障碍以及数字技能缺陷联系起来。然而，关于这些解释中的任何一种是否是特纳综合征中MLD的基础也存在相互矛盾的证据。总体而言，特纳综合征女孩的大多数数学困难出现在限时测试或复杂问题上。在非限时测试中，成绩测试分数可能与年龄相符。因此，特纳综合征认知表型中包含MLD提醒我们，不能仅根据非限时计算子测试的表现就排除MLD，这对许多研究人员广泛采用的做法构成了挑战，即根据广泛的数学成绩测试结果来定义MLD。
