Restricted and repetitive behaviors (RRBs) are core features of autism spectrum disorder (ASD) and one of the earliest behavioral signs of ASD. However, RRBs are also present in typically developing (TD) infants, toddlers, and preschool-aged children. Past work suggests that examining change in these behaviors over time is essential to distinguish between normative manifestations of these behaviors and behaviors that denote risk for a neurodevelopmental disorder. One challenge in examining changes in these behaviors over time is that most measures of RRBs have not established longitudinal measurement invariance. The aims of this study were to (1) establish measurement invariance in the Repetitive Behavior Scales for Early Childhood (RBS-EC), a parent-report questionnaire of RRBs, and (2) model developmental change in RRBs from 8 to 36 months. We collected RBS-EC responses from parents of TD infants (n = 180) from 8 to 36 months (n = 606 responses, with participants contributing an average of 3-time points). We leverage a novel methodological approach to measurement invariance testing (Bauer, Psychological Models, 22(3), 507–526, 2017), moderated nonlinear factor analysis (MNLFA), to determine whether the RBS-EC was invariant across age and sex. We then generated adjusted factor score estimates for each subscale of the RBS-EC (repetitive motor, self-directed, and higher-order behaviors), and used linear mixed effects models to estimate between- and within-person changes in the RBS-EC over time. The RBS-EC showed some non-invariance as a function of age. We were able to adjust for this non-invariance in order to more accurately model changes in the RBS-EC over time. Repetitive motor and self-directed behaviors showed a linear decline from 8 to 36 months, while higher-order behaviors showed a quadratic trajectory such that they began to decline later in development at around 18 months. Using adjusted factor scores as opposed to unadjusted raw mean scores provided a number of benefits, including increased within-person variability and precision. The RBS-EC is sensitive enough to measure the presence of RRBs in a TD sample, as well as their decline with age. Using factor score estimates of each subscale adjusted for non-invariance allowed us to more precisely estimate change in these behaviors over time.

中文翻译：

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8-36 个月限制性和重复性行为的纵向变化

限制性和重复性行为 (RRB) 是自闭症谱系障碍 (ASD) 的核心特征，也是 ASD 最早的行为体征之一。然而，RRB 也存在于典型发育 (TD) 婴儿、幼儿和学龄前儿童中。过去的工作表明，检查这些行为随时间的变化对于区分这些行为的规范表现和表示神经发育障碍风险的行为至关重要。在检查这些行为随时间变化的过程中面临的一个挑战是，大多数 RRB 测量尚未建立纵向测量不变性。本研究的目的是 (1) 在儿童早期重复行为量表 (RBS-EC)、RRB 父母报告问卷中建立测量不变性，以及 (2) 对 RRB 从 8 个月到 36 个月的模型发育变化。我们收集了 8 至 36 个月的 TD 婴儿（n = 180）父母的 RBS-EC 反应（n = 606 反应，参与者平均贡献了 3 个时间点）。我们利用一种新的方法论来测量不变性测试（Bauer，Psychological Models，22(3)，507-526，2017），适度非线性因子分析 (MNLFA)，以确定 RBS-EC 是否在不同年龄和性别之间保持不变。然后，我们为 RBS-EC 的每个子量表（重复运动、自我导向和高阶行为）生成了调整后的因子评分估计值，并使用线性混合效应模型来估计 RBS-EC 中人与人之间的变化随着时间的推移。RBS-EC 显示出一些作为年龄函数的非不变性。我们能够针对这种非不变性进行调整，以便更准确地模拟 RBS-EC 随时间的变化。重复性运动和自我导向行为从 8 个月到 36 个月呈线性下降，而高阶行为则呈二次曲线，因此它们在 18 个月左右的发育后期开始下降。使用调整后的因素分数而不是未调整的原始平均分数提供了许多好处，包括增加人内可变性和精确度。RBS-EC 足够灵敏，可以测量 TD 样本中 RRB 的存在以及它们随年龄的下降。使用针对非不变性调整的每个子量表的因子得分估计使我们能够更准确地估计这些行为随时间的变化。使用调整后的因子分数而不是未调整的原始平均分数提供了许多好处，包括增加人内可变性和精确度。RBS-EC 足够灵敏，可以测量 TD 样本中 RRB 的存在以及它们随年龄的下降。使用针对非不变性调整的每个子量表的因子得分估计使我们能够更准确地估计这些行为随时间的变化。使用调整后的因素分数而不是未调整的原始平均分数提供了许多好处，包括增加人内可变性和精确度。RBS-EC 足够灵敏，可以测量 TD 样本中 RRB 的存在以及它们随年龄的下降。使用针对非不变性调整的每个子量表的因子得分估计使我们能够更准确地估计这些行为随时间的变化。