This study has three main objectives. First, the investigators want to see how using a lightweight head-mounted eye tracker (HMET) can help to understand looking behavior, visual focus, and social interaction in toddlers with motor delays during ROC-Stand training. The investigators will compare the effects of training with specific environmental features to training without these features and to conventional therapy. Second, the investigators will evaluate outcomes related to body function, daily activities, and participation, along with family perceptions and involvement, using the ICF framework. Third, the investigators will explore how temperament, motivation, looking behavior, and caregiver-child interactions relate to each other in these toddlers across different training programs.

Based on previous research, the investigators plan to recruit 30 toddlers with motor delays and randomly assign them to one of three groups: ROC-Stand with specific environmental features (ROC-Stand(SE)), ROC-Stand without these features (ROC-Stand(NSE)), and conventional therapy (Control), with 10 toddlers in each group. Each toddler will receive a total of 48 hours of training over 24 weeks, with two 120-minute sessions per week-12 weeks of intervention followed by a 12-week follow-up. The participants will also continue their regular therapy during the study. The HMET will record visual and manual behaviors for 20 minutes each week, and standardized assessments of body function, mobility, psychosocial function, family perception, and participation will be done before the intervention, after the intervention, and at the end of the follow-up.

The findings from this study will help identify key environmental factors for early power mobility training and provide families and therapists with a clear, structured approach to using these techniques.

Environmental and task modifications are widely used in pediatric rehabilitation to help shape children's actions. However, therapists often adjust these factors by trial and error. A better understanding of how to optimize the "fit" between a child and their surroundings could lead to a more systematic approach, making it easier for children to develop new actions. Head-mounted eye trackers (HMETs) are wearable devices that record eye movements in real-world settings. By combining ROC (ride-on car) training with HMET technology, the investigators can track the visual and touch-based information that young children gather as they use power mobility devices (PMDs). This new approach helps to see how toddlers interact with their environment, deepening our understanding of their development.

This research project focuses on three key aims: 1) Evaluating the effects of ROC-Stand training programs, both with and without specific environmental features, on the looking behaviors and social interactions of toddlers with motor delays, compared to a control group receiving conventional therapy; 2) Determining the effectiveness of these programs in achieving various outcomes as categorized by the International Classification of Disability, Functioning, and Health (ICF) framework for toddlers with motor delays; and 3) Investigating how these training programs affect the relationship among children's temperament, mastery motivation, looking behaviors, and caregiver-child interactions in toddlers with motor delays.

Study design: The investigators will use a randomized, pretest-posttest control group design with three groups. The study will involve a three group comparison: two ROC training programs, differentiated by the inclusion (ROC-Stand(SE)) or exclusion (ROC-Stand(NSE)), of specific environmental features, and a control group receiving conventional therapy. All groups will have an identical training schedule: 2-hour sessions, conducted twice a week for a 12-week period. The duration of the study for each participant is set at 6 months, which includes a 3-month intervention period followed by a 3- month follow-up phase. Participants will continue their regular therapy sessions throughout the study.

Participants: The study will include 30 toddlers, aged between 12 to 36 months, who have motor delays. These participants will be randomly assigned into three groups, each consisting of 10 toddlers: the ROC-Stand(SE) group, the ROC-Stand(NSE) group, or the Control group. The sample size for our study on early powered mobility training is determined based on an effect size (f) of 0.3, as observed in a previous ROC-Stand RCT that assessed social function in PEDI-C. This calculation takes into account a statistical power of 0.8, a two-sided type I error rate of 0.05, an anticipated dropout rate between 20 to 25%, and recruitment conditions from prior studies.

Recruitment: Participants will be recruited through self-referrals, healthcare practitioners, and hospitals in Taoyuan or New Taipei where toddlers receive outpatient rehabilitation. Flyers will be distributed in clinical settings, and interested parents will be contacted to explain the study details. Informed consent will be obtained before enrollment.

Procedure: Before the intervention, toy cars will be modified for safety-seats will be adjusted and the acceleration system changed to a switch. Toddlers in the ROC training groups will receive these custom-made, standing-style cars. Pre-intervention assessments will be conducted by an independent occupational therapist who is unaware of the study's goals and group assignments. These assessments, carried out in a testing room at Chang Gung University, will occur at three time points: before training (T1), three months into training (T2), and three months after training ends (T3). The assessments will take place in a testing room at Chang Gung University, occurring at three different times: before training (T1), three months after the start of the training (T2), and three months following the end of the training (T3). All participants will begin their respective training programs at the university. During the intervention, each toddler will wear a lightweight HMET for 20 minutes once a week to record eye gaze, manual actions, and social interactions. An activity log will document the training conditions and capture caregivers' weekly feedback. In the follow-up phase, participants will not receive any training from our research team. Instead, they will continue with their regular therapy at their clinics. We will gather information about this regular therapy, including its type, frequency, and dosage, at three time points: T1, T2, and T3. All eye-tracking data will be analyzed by two independent coders, who are undergraduate students. Before they begin their analysis, the principal investigator (PI) will instruct them on coding procedures. To ensure reliability, Cohen's kappa coefficient will be calculated between the two raters before formal coding.

Intervention (training phase): One licensed occupational therapist who is responsible for providing the training programs, will collaborate with caregivers to set goals and track progress using goal attainment scaling (GAS) at T1, T2, and T3 for all three groups. These goals will pertain to aspects of mobility and psychosocial functions. The ROC-related training programs will involve one therapist working closely with the caregivers, employing coaching techniques from the FCS model. Furthermore, the programs incorporate a standing posture and are context-focused. The conventional therapy program, on the other hand, is a child-centered, therapist-directed approach. Participants will be allowed necessary breaks during training sessions based on their endurance. In addition, all participants in the three groups will wear a lightweight HMET (weighing 46 g) from Positive Science, LLC to record their looking, fixation, and interactive behaviors during one session per week of the intervention. All participants will continue their regular therapy (e.g., physical, occupational, speech therapy) throughout the 6-month study.

Follow-up: During this period, a follow-up phase will take place after the completion of the training programs mentioned above. In this phase, participants will not receive any additional training programs from the study but will continue with their regular therapy sessions.

Inclusion Criteria:

1. aged between 1 to 3 years
2. having motor delays that either prevent independent walking or require the use of assistive technology for walking, defined as more than 1.5 standard deviations(SD) below the mean, as evaluated by the Chinese Child Development Inventory via a physician
3. able to stand independently for at least two seconds or can tolerate standing with support for up to 10 minutes
4. capable of reaching for objects with either one or both hands
5. with a height ranging from 69 to 103 cm and a weight between 7 to 18 kg
6. having parents who can provide consent for their child's participation in the training programs

Exclusion Criteria:

1. children with severe sensory impairments, such as blindness or deafness
2. children whose height falls outside the range of 69 to 103 cm and weight outside the range of 7 to 18 kg
3. parents or caregivers who are unable to commit the time required for the training phase
4. children who exhibit severe emotional reactions that could potentially lead to harm