Dale Philip S, Rice Mabel L, Rimfeld Kaili, Hayiou-Thomas Marianna E
Department of Speech & Hearing Sciences, University of New Mexico, Albuquerque.
Department of Speech-Language-Hearing: Sciences & Disorders, The University of Kansas, Lawrence.
J Speech Lang Hear Res. 2018 Jan 22;61(1):66-78. doi: 10.1044/2017_JSLHR-L-16-0364.
There is a need for well-defined language phenotypes suitable for adolescents in twin studies and other large-scale research projects. Rice, Hoffman, and Wexler (2009) have developed a grammatical judgment measure as a clinical marker of language impairment, which has an extended developmental range to adolescence.
We conducted the first twin analysis, along with associated phenotypic analyses of validity, of an abridged, 20-item version of this grammatical judgment measure (GJ-20), based on telephone administration using prerecorded stimuli to 405 pairs of 16-year-olds (148 monozygotic and 257 dizygotic) drawn from the Twins Early Development Study (Haworth, Davis, & Plomin, 2012).
The distribution of scores is markedly skewed negatively, as expected for a potential clinical marker. Low performance on GJ-20 is associated with lower maternal education, reported learning disability (age 7 years), and low scores on language tests administered via the Twins Early Development Study (age 16 years) as well as General Certificate of Secondary Education English and Math examination performance (age 16 years). Liability threshold estimates for the genetic influence on low performance on GJ-20 are substantial, ranging from 36% with a lowest 10% criterion to 74% for a lowest 5% criterion.
The heritability of GJ-20 scores, especially at more extreme cutoffs, along with the score distribution and association with other indicators of language impairments, provides additional evidence for the potential value of this measure as a clinical marker of specific language impairment.
在双胞胎研究和其他大规模研究项目中，需要有适用于青少年的明确语言表型。赖斯、霍夫曼和韦克斯勒（2009年）开发了一种语法判断测量方法，作为语言障碍的临床标志物，其发展范围已扩展到青少年期。
我们基于对405对16岁青少年（148对同卵双胞胎和257对异卵双胞胎）进行电话施测，使用预先录制的刺激材料，对这种语法判断测量方法（GJ - 20）的一个缩减版（20项）进行了首次双胞胎分析以及相关的效度表型分析，这些双胞胎来自双胞胎早期发展研究（霍沃思、戴维斯和普洛明，2012年）。
正如对一个潜在临床标志物所预期的那样，分数分布明显呈负偏态。GJ - 20表现不佳与母亲受教育程度较低、报告的学习障碍（7岁时）、通过双胞胎早期发展研究进行的语言测试（16岁时）得分较低以及普通中等教育证书英语和数学考试成绩（16岁时）较低相关。GJ - 20表现不佳的遗传影响的责任阈值估计相当大，从最低10%标准下的36%到最低5%标准下的74%不等。
GJ - 20分数的遗传性，尤其是在更极端的临界值时，以及分数分布和与其他语言障碍指标的关联，为该测量方法作为特定语言障碍临床标志物的潜在价值提供了额外证据。
