Institute of Child Development, University of Minnesota, 51 East River Parkway, Minneapolis, MN, 55455, USA.
Department of Educational Psychology, University of Minnesota, Minneapolis, MN, USA.
J Neurodev Disord. 2021 Jan 11;13(1):7. doi: 10.1186/s11689-020-09335-0.
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.
限制和重复行为（RRBs）是自闭症谱系障碍（ASD）的核心特征，也是 ASD 的最早行为迹象之一。然而，RRBs 也存在于正常发育（TD）的婴儿、幼儿和学龄前儿童中。过去的研究表明，检查这些行为随时间的变化对于区分这些行为的正常表现和表示神经发育障碍风险的行为至关重要。检查这些行为随时间的变化所面临的一个挑战是，大多数 RRBs 测量方法都没有建立纵向测量不变性。本研究的目的是：（1）建立早期儿童重复行为量表（RBS-EC）的测量不变性，RBS-EC 是一种 RRBs 的父母报告问卷；（2）对 8 至 36 个月期间 RRBs 的发展变化进行建模。
我们从 8 至 36 个月（606 次应答，参与者平均贡献 3 个时间点）的 TD 婴儿的父母那里收集了 RBS-EC 的应答。我们利用一种新的测量不变性测试方法（Bauer，Psychological Models，22（3），507-526，2017），即调节非线性因素分析（MNLFA），来确定 RBS-EC 是否在年龄和性别上具有不变性。然后，我们为 RBS-EC 的每个子量表（重复运动、自我导向和高级行为）生成调整后的因子得分估计值，并使用线性混合效应模型来估计 RBS-EC 随时间的个体间和个体内变化。
RBS-EC 表现出一些随年龄变化的非不变性。我们能够对此进行调整，以便更准确地对 RBS-EC 随时间的变化进行建模。重复运动和自我导向行为从 8 至 36 个月呈线性下降，而高级行为则呈二次轨迹，即在大约 18 个月时开始在发育后期下降。使用调整后的因子得分而不是未经调整的原始平均值作为输入可以带来许多好处，包括增加个体内的可变性和精确性。
RBS-EC 足以在 TD 样本中测量 RRBs 的存在，以及它们随年龄的下降。使用经过非不变性调整的每个子量表的因子得分估计值，可以更精确地估计这些行为随时间的变化。
