Single-case Experimental Design Research Articles

Estimating Mediation Effects in ABAB Reversal Designs

Single-Case Experimental Designs (SCEDs), or N-of-1 trials, are commonly used to estimate intervention effects in many disciplines including in the treatment of youth mental health problems. SCEDs consist of repeated measurements of an outcome over time for a single case (e.g., student or patient) throughout one or more baseline phases and throughout one or more intervention phases. The manipulation of the baseline and intervention phase make the SCED a type of interrupted time series design, which is considered one of the most effective experimental designs for causal inference. An important step towards understanding why interventions are effective at producing a change in the outcome is through the investigation of mediating mechanisms. Hypotheses of mediating mechanisms involve an intervention variable which is hypothesized to affect an outcome through its effect on a mediating variable. Little work has attempted to combine mediation analysis and ABAB reversal designs. Therefore, the goals of this paper are to define, estimate, and interpret mediation effects for ABAB reversal designs. An empirical example is used to demonstrate how to estimate and interpret the mediation effects. R code is provided for researchers interested in estimating mediation effects in single-case reversal designs.

Discovering Internal Validity Threats and Operational Concerns in Single-Case Experimental Designs Through Directed Acyclic Graphs

Discovering Internal Validity Threats and Operational Concerns in Single-Case Experimental Designs Through Directed Acyclic Graphs

Efficacy of Complexity-Based Target Selection for Treating Morphosyntactic Deficits in Children With Developmental Language Disorder and Children With Down Syndrome: A Single-Case Experimental Design.

Selecting targets for morphosyntactic intervention is a critical component of treatment planning. The complexity approach suggests that, by treating a complex morphosyntactic target, improvements will occur for the treated structure and for related, simpler structures. This study evaluated the efficacy of the complexity approach for treating morphosyntactic deficits by targeting a complex BE verb question structure for children with developmental language disorder (DLD) and children with Down syndrome (DS) and observing its impact on treated and untreated BE verb structures. We also explored whether etiology impacted our participants' treatment responses. Three participants with DLD and three with DS received treatment for the BE verb question structure in the context of a single-case multiple-baseline design across participants. Accuracy of production for the treated structure and untreated BE verb structures was measured across baseline, treatment, and posttreatment phases. Treatment of the complex BE verb question structure resulted in change on the treated structure for three participants (i.e., two with DLD and one with DS). Generalization of treatment to untreated, related BE verb structures occurred for all six participants. Outcomes indicated participants from both etiologies benefited from treatment. This study provides evidence supporting the use of a complexity-based approach for selecting morphosyntactic treatment targets for children with DLD and children with DS. Additional research is needed to identify specific characteristics that may influence individual treatment responses. https://doi.org/10.23641/asha.27018124.

Pilot study protocol evaluating the impact of telerobotics interactions with autistic children during a Denver intervention on communication skills using single-case experimental design

IntroductionFor several years, studies have been conducted on the contribution of social robots as an intervention tool for children with autism spectrum disorder (ASD). One of the early intervention models...

Web-based Acceptance and Commitment Therapy (ACT) for adults living with cancer: A Single Case Experimental Design (SCED)

A randomised multiple-baseline design assessed the preliminary efficacy of a low-intensity, minimally-guided, online, self-help Acceptance and Commitment Therapy (ACT) intervention for people affected by cancer on quality of life (QoL), psychological symptoms, psychological flexibility, and level of interference from pain and fatigue. Acceptability and feasibility was also assessed. Adult participants (n = 7) had either completed cancer treatment within the last 18 months or were currently receiving treatment. Participants were randomly assigned to a baseline length of 1-3 weeks prior to completing the six-week ACT intervention, followed by a one-month follow-up. At pre- and post-intervention, and one-month follow-up, cancer-specific QoL, psychological symptoms (anxiety and depression), and psychological flexibility were assessed using standardised questionnaires. Single-item daily ratings of mood, anxiety, psychological flexibility, and bother ratings of pain and fatigue were also assessed. Questionnaire data were analysed using reliable and clinically significant change. Daily measures were analysed using visual and Tau-U analysis. Participants reported less negative impact of cancer on QoL (n = 3: CancerDQoL), fewer depressive symptoms (n=5: HADS depression) and greater psychological flexibility (n=3: MPFI) at follow-up. Daily measures showed improvements in self-reported mood (n=3), anxiety (n=3) and psychological flexibility (n=5) across different phase comparisons. Most participants (n=5) were significantly less bothered by fatigue at follow-up, and two were significantly less bothered by pain. Feedback from participants supported the acceptability of the intervention. The results provide preliminary support for the efficacy of the ACT intervention in reducing the negative impact of cancer on QoL, and improving self-reported psychological outcomes and psychological flexibility. Longitudinal studies utilising a larger sample are warranted.

Functional Communication Training in Schools: A Systematic Analysis of the Evidence for Ecological Validity.

Ecological validity refers to the meaningfulness or practical significance of research outcomes in everyday settings or the extent to which an intervention can be implemented by typical people during naturally occurring opportunities. In education, ecological validity may contribute to the adoption of interventions by teachers working with students in school settings. Our purpose in this review was to examine the evidence for ecological validity of functional communication training (FCT) used to address challenging behavior in school-age individuals with disabilities. We reviewed 19 single-case experimental design (SCED) studies published between 1985 and 2023. First, we used the What Works Clearinghouse (WWC) Standards to evaluate the empirical evidence of each study. Second, we evaluated the extent to which behavioral assessment and FCT procedures were described in the 15 studies that met the WWC Standards. Third, we conducted a systematic analysis of the evidence for ecological validity of behavioral assessment and FCT. Results indicate that 95% of the SCED studies met the WWC Standards. The description of procedures was complete for 50% of the behavioral assessments and for 11% of the FCT. The overall evidence for ecological validity was moderate for 16.7% and low for 83.3% of the behavioral assessments. The evidence for ecological validity for all FCT procedures was low. Future research and implications related to ecological validity are discussed.

Harnessing Available Evidence in Single-Case Experimental Studies: The Use of Multilevel Meta-Analysis.

The use of multilevel models to combine and compare the results of multiple single-case experimental design (SCED) studies has been proposed about two decades ago. Since then, the number of multilevel meta-analyses of SCED studies steadily increased, together with the complexity of multilevel models used. At the same time, many studies were done to empirically evaluate the approach in a variety of situations, and to study how the flexibility of multilevel models can be employed to account for many complexities that often are encountered in SCED research, such as autocorrelation, linear and nonlinear time trends, specific designs, external event effects, multiple outcomes, and heterogeneity. In this paper, we give a state-of-the-art of the multilevel approach, by making an overview of basic and more extended models, summarizing simulation results, and discussing some remaining issues.

Family therapy and EMDR after child abuse and neglect: moderating effects of child attachment style and PTSD symptoms on treatment outcome

ABSTRACT Background: Effective and appropriate care and treatment for children in order to decrease the psychosocial problems that arose after experiencing child abuse and neglect (CAN) is of vital importance, given the severity of symptomatology that may develop. Objective: The purpose of the present study was to examine whether attachment style and core cluster Posttraumatic Stress Disorder symptoms acted as moderators for treatment outcomes of a new integrative treatment model for trauma and attachment. In this treatment model, family therapy is combined with EMDR and obstacles for trauma processing are tackled first. Method: we included children, ages 6–12 years, with a history of CAN, who did not respond to evidence-based trauma treatment. Target treatment outcomes were problems in attachment, posttraumatic stress symptoms, behaviour, and emotion regulation. We conducted a multiple-baseline ABC Single-Case Experimental Design (SCED). We categorized 12 participants into four groups of attachment style and core cluster PTSD symptoms: (1) non-disorganized & re-experiencing; (2) non-disorganized & avoidance/hyperarousal; (3) disorganized & re-experiencing; & (4) disorganized & avoidance/hyperarousal. We compared the four groups with each other and across time, and the interaction between groups and effect over time. We conducted non-parametric permutation tests and estimated q-values for false discovery rate control. Results: Children with a disorganized attachment style had more severe symptomatology in general, except for posttraumatic stress symptoms. The treatment appeared more effective in targeting and successfully treating children with a non-disorganized attachment style, and specifically children with a non-disorganized attachment style and re-experiencing as core cluster PTSD symptoms. Conclusion: Our study underlines the complexity of treating children who developed a complicated combination of symptomatology after CAN and calls for the continuous development of innovative interventions.

Supporting adherence to a home practice reading program using self-monitoring in persons with aphasia: a single case experimental design study

ABSTRACT Background Impairments in reading comprehension impact participation in daily activities for persons with aphasia. Home practice programs can be used by speech-language pathologists to extend treatment by providing additional practice to support recovery. However, adherence to home programs is often low and factors that enhance adherence to home programs are poorly understood. Aims We sought to examine if using self-monitoring practice with an aphasia-friendly logbook and a timer is an effective mechanism to support home program adherence and to explore the perception of this technique by individuals with aphasia. Methods & procedures This non-concurrent multiple baseline single case experimental design was completed during the COVID-19 Pandemic. Procedures were completed virtually or in person. If in person, assessments were done in the clinic or in the participant’s home. The participants (n = 6) were at least six months post-stroke, diagnosed with aphasia, and reported interest in practicing reading. There were five males and one female. During the baseline phase, participants received training on a mobile reading comprehension application on an iPad. They were instructed to practice reading 80 minutes seven days a week, and were not provided with self-monitoring supports, but were given a single cue card that indicated the practice expectation. The number of data points in the baseline phase was at least five and increased across participants. At the end of baseline, participants received training on the use of a timer and an aphasia-friendly logbook for self-monitoring minutes of practice. They were instructed to continue practicing for 80 minutes every day. In both phases, participants received weekly check-ins to ensure the technology was working. Outcomes & results The primary outcome measures were minutes of practice and percent adherence. Three out of the six participants demonstrated an effect with the self-monitoring intervention with more minutes of practice or greater percent adherence during the intervention phase. Responders typically had higher self-efficacy for exercise scores and a shorter baseline phase. Three participants did not demonstrate an effect of the self-monitoring intervention. The logbook was reported as one of the two most helpful features of the intervention by all the participants with weekly technology check-ins and iPad training as the least helpful elements. Conclusions Self-monitoring with an aphasia-friendly logbook and timer can support some individuals with aphasia in achieving a greater amount of home program practice. Additional research with a larger more diverse sample that incorporates timing and self-efficacy for exercise is warranted.

Treating narcolepsy-related nightmares with cognitive behavioural therapy and targeted lucidity reactivation: A pilot study.

Nightmares are a common symptom in narcolepsy that has not been targeted in prior clinical trials. This study investigated the efficacy of Cognitive Behavioural Therapy for Nightmares (CBT-N), adapted for narcolepsy, in a small group of adults. Given the high prevalence of lucid dreaming in narcolepsy, we added a promising adjuvant component, targeted lucidity reactivation (TLR), a procedure designed to enhance lucid dreaming and dream control. Using a multiple baseline single-case experimental design, adults with narcolepsy and frequent nightmares (≥3/week, N = 6) were randomised to a 2 or 4 week baseline and received seven treatment sessions (CBT-N or CBT-N + TLR). Across the groups, there was a large effect size (between-case standardised mean difference [BC-SMD] = -0.97, 95% CI -1.79 to -0.14, p < 0.05) for reduced nightmare frequency from baseline (M = 8.38/week, SD = 7.08) to posttreatment (M = 2.25/week, SD = 1.78). Nightmare severity improved significantly with large effect sizes on sleep diaries (BC-SMD = -1.14, 95% CI -2.03 to -0.25, p < 0.05) and the Disturbing Dream and Nightmare Severity Index (z = -2.20, p = 0.03, r = -0.64). Treatment was associated with a reduction for some participants in sleep paralysis, sleep-related hallucinations, and dream enactment. NREM parasomnia symptoms (z = -2.20, p = 0.03, r = -0.64) and self-efficacy for managing symptoms (z = -2.02, p = 0.04, r = -0.58) improved significantly with large effect sizes. Participants who underwent TLR (n = 3) all recalled dreams pertaining to their rescripted nightmare. In interviews, participants noted reduced shame and anxiety about sleep/nightmares. This study provides a proof of concept for the application of TLR as a therapeutic strategy with clinical populations, as well as preliminary evidence for the efficacy of CBT-N in treating narcolepsy-related nightmares.

Effectiveness of a Person-Centered Interdisciplinary Rehabilitation Treatment of Post-COVID-19 Condition: Protocol for a Single-Case Experimental Design Study.

Patients with post-COVID-19 condition (PCC) experience a wide range of complaints (physical, cognitive, and mental), sometimes with high levels of disability in daily activities. Evidence of effective interdisciplinary rehabilitation treatment is lacking. A person-centered, biopsychosocial, interdisciplinary rehabilitation program, adapted to expert opinions and the patient's needs, was therefore developed. This study aims to present a study protocol for a clinical trial to evaluate the effect of a new, person-centered, interdisciplinary rehabilitation treatment for PCC. It is aimed at improving participation in society and health-related quality of life in patients with PCC who perceive a high level of disability in daily activities or participation. A total of 20 Dutch adults, aged 18 years or older, with high levels of disability in daily activities and participation in society will be included in this replicated and randomized single-case experimental design study, from October 2023 onward. The replicated and randomized single-case experimental design consists of 3 phases. The baseline phase is the observational period, in which no specific treatment will be given. In the intervention phase, patients will receive the new outpatient treatment 3 times a week for 12 weeks, followed by a 12-week follow-up phase. During the intervention phase, the treatment will be personalized according to the patient's physical, mental, and cognitive symptoms and goals. The treatment team can consist of a rehabilitation physician, physiotherapist, occupational therapist, speech therapist, and psychologist. The primary outcomes of the study are daily diaries, which consist of 8 questions selected from validated questionnaires (Utrecht Scale for Evaluation of Rehabilitation-Participation, EQ-5D-5L, and the Hospital Anxiety and Depression Scale). The other primary outcome measurements are participation in society (Utrecht Scale for Evaluation of Rehabilitation-Participation) and health-related quality of life (EQ-5D-5L). The secondary outcomes are physical tests and validated questionnaires aimed at physical, mental, and cognitive complaints. Effect evaluation based on daily assessments will include visual analysis, calculation of effect sizes (Nonoverlap of All Pairs), randomization tests, and multilevel analysis. In addition, other analyses will be based on ANOVA or a 2-tailed Student t test. Data collection for this study started in October 2023 and is planned to be completed in July 2024. The results will be published in peer-reviewed journals and presented at international conferences. This is the first study investigating the effect of an interdisciplinary rehabilitation treatment with a person-centered, biopsychosocial approach in patients with PCC. Our findings will help to improve the treatment and support of patients with PCC. German Clinical Trials Register DRKS00032636; https://drks.de/search/en/trial/DRKS00032636. DERR1-10.2196/63951.

Delivering Enhanced Milieu Teaching to Toddlers With Down Syndrome via Hybrid Telepractice: A Single-Case Experimental Design.

This pilot study investigated delivering enhanced milieu teaching tailored for children with Down Syndrome (EMT-DS) through hybrid telepractice. In this multiple-baseline design across behaviors study, a speech-language pathologist (SLP) taught EMT-DS to three caregivers and their children with DS (22-40 months) using a hybrid service delivery model. Sessions were conducted in person and via telepractice. The SLP taught caregivers EMT-DS, emphasizing the use of (a) four target EMT strategies: matched turns, expansions, time delays, and milieu teaching episodes; (b) augmentative and alternative communication (AAC; manual signs, speech-generating device); and (c) aided AAC modeling. The SLP provided caregiver instruction following the teach-model-coach-review approach. Caregiver outcomes were the accuracy (primary) and frequency (secondary) of EMT strategy use. Child outcomes were exploratory and included the rate of symbolic communication acts, weighted number of communication acts, and number of different words (NDW). There was a functional relation between the intervention and the accuracy and frequency of EMT strategy use for all three caregivers. All caregivers showed an increase in the accuracy for all four target strategies. Caregivers also increased the frequency of the three EMT strategies: expansions, time delays, and milieu teaching episodes. There were no changes in the frequency of matched turns. Caregiver use of EMT strategies maintained for 6 weeks post-intervention. After caregivers learned EMT strategies, gradual increases in the rate of symbolic communication acts and NDW occurred for all three children. Results demonstrate the preliminary efficacy of using a hybrid service delivery model to teach caregivers EMT-DS. https://doi.org/10.23641/asha.27115252.

Introduction to the Special Issue: Focus on Families

Engaging with families to support their children’s social, emotional, and behavioral development is a key feature of positive behavior supports (PBSs). The purpose of this Special Series is to disseminate research on the application of PBSs with families and in home contexts. This issue contains five articles, including single case experimental designs, survey design, mixed-methods, and a literature synthesis. These articles provide a deeper understanding and clear implications for improving research and practice to increase family access, involvement, and benefit from PBSs.

Assessing the Effectiveness of an mHealth Intervention to Support Men Who Have Sex With Men Engaging in Chemsex (Budd): Single-Case and Pre-Post Experimental Design Study.

This study focuses on the Budd app, a mobile health intervention designed for gay, bisexual, and other men who have sex with men who participate in chemsex. Chemsex, the use of psychoactive drugs in a sexual context, presents substantial health risks including increased HIV transmission and mental health issues. Addressing these risks requires innovative interventions tailored to the unique needs of this population. This study aims to evaluate the effectiveness of the Budd app in promoting drug harm reduction practices among its users, focusing on knowledge, behavioral intention, risk behavior awareness, and self-efficacy. The study used a mixed methods approach, combining a single-case experimental design and a pre-post study. A total of 10 participants from an outpatient clinic were recruited, and each attended the clinic 3 times. During the first visit, participants installed a restricted version of the Budd app, which allowed them to report daily mood and risk behavior after chemsex sessions. Phase A (baseline) lasted at least 2 weeks depending on chemsex participation. In the second visit, participants gained full access to the Budd app, initiating phase B (intervention). Phase B lasted at least 6 weeks, depending on chemsex participation, with identical data input as phase A. Participants completed pre- and postintervention surveys assessing behavioral determinants during the first and third visit. The study observed an increased knowledge about chemsex substances postintervention, with a mean percentage improvement in knowledge scores of 20.59% (SD 13.3%) among participants. Behavioral intention and self-efficacy showed mixed results, with some participants improving while others experienced a decrease. There was also a variable impact on awareness of risk behavior, with half of the participants reporting a decrease postintervention. Despite these mixed results, the app was generally well-received, with participants engaging with the app's features an average of 50 times during the study. The Budd app showed effectiveness in enhancing knowledge about chemsex substances among gay, bisexual, and other men who have sex with men. However, its impact on safe dosing behavior, behavioral intention, self-efficacy, and risk behavior awareness was inconsistent. These findings suggest that while educational interventions can increase knowledge, translating this into behavioral change is more complex and may require more participants, a longer follow-up period, and additional strategies and support mechanisms.

The role of single case experimental designs in evidence creation in rehabilitation.

Randomized controlled trials (RCTs) are considered the gold standard of evidence guiding intervention selection in rehabilitation. However, conduct of sufficiently powered RCTs in rehabilitation can be expensive, pose ethical and attrition concerns when participants are assigned to ineffective treatment as usual conditions, and are infeasible with low-incidence populations. Single-case experimental designs (SCEDs), including N-of-1 RCTs are causal inference studies for small numbers of participants and not necessarily one participant as the name implies. These designs are increasingly used to evaluate the effectiveness of rehabilitation interventions in diverse clinical settings and employ design features including but not limited to randomization and each participant serving as their own control. These and other internal validity enhancements can increase the confidence in study results coming from these designs. This manuscript discusses the expanded application of SCEDs in rehabilitation contexts to answer everyday clinical rehabilitation research questions with emphasis on strategies to use: 1) to maximize internal validity of this family of designs; 2) improve utility, effectiveness, and acceptability of these designs for rehabilitation end-users (clinicians, policymakers, and participants); 3) build evidence bases in areas of rehabilitation where RCTs are uncommonly used. Primary considerations for situating SCEDs within the continuum of experimental designs include increasing internal validity within designs, improving transparency in conduct and reporting of these studies, and increasing access to advanced research methods training for rehabilitation professionals.

Effectiveness of Trauma-Focused Art Therapy (TFAT) for psychological trauma: A mixed method single case study

Art therapy (AT) shows promise in treating clients with posttraumatic stress disorder (PTSD), especially those who don't respond well to traditional treatments (more than 30 %). This case study aimed to explore the effects of Trauma-Focused Art Therapy (TFAT) on PTSD symptoms and establish its viability as a non-verbal therapy for trauma-related issues. A 10-week intervention and a 3-week follow-up phase were explored using a mixed method single case experimental design (SCED) aimed at integrated results. Bringing the two types of data together adds value and enables to understand the findings better. Quantitative data was collected with weekly questionnaires focused on severity of depression, resilience, self-esteem, mental health and self-expression and emotion regulation in art therapy. The PTSD Checklist for DSM-5 (PCL-5) was completed in week 1 and 10. Qualitative data was collected through interviews, the patient dossier, and artwork. The combined findings indicate a decrease in PTSD symptoms, reduced depression symptoms, enhanced emotional articulation, increased mental resilience, self-esteem, and positive mental health. The qualitative data support these results, and also add improved emotional connection, increased emotional acknowledgment, and enhanced self-compassion. Based on the combined results of this mixed method design we understand that the TFAT protocol led to a clinically significant reduction in PTSD symptoms and improved mental health, demonstrating effectiveness of AT for trauma in this case. This is the first study that tested the TFAT protocol in posttraumatic distress.

Feasibility of a home-based home videogaming intervention with a family-centered approach for children with cerebral palsy: a randomized multiple baseline single-case experimental design

BackgroundWorldwide, children with cerebral palsy (CP) living in underserved communities face barriers to accessing motor therapy services. This study assessed the implementation and effectiveness of an 8-week, upper limb (UL) home-based intervention with a movement-tracking videogame (Bootle Blast) in Costa Rican children with CP.MethodsChildren established a weekly playtime goal and two UL activities of daily living (ADLs) that they would like to improve on. A multiple-baseline, single-case experimental design, was used with the Performance Quality Rating Scale (PQRS) as the repeated measure to track changes in performance of the selected ADLs between the baseline (usual care) and intervention (Bootle Blast) phases. The Canadian Occupational Performance Measure (COPM), the Box and Blocks Test (BBT) and the Children’s Hand-Use Experience Questionnaire (CHEQ) were collected before and after the intervention. Technical barriers were documented during weekly video calls with a monitoring therapist. Treatment effect size, slope changes and percentage of non-overlapping data were identified for the PQRS. Descriptive statistics summarized results for the BBT, CHEQ, videogame logs (e.g., playtime) and technical barriers.ResultsFifteen children participated and 13 completed the intervention. Both participants who dropped out did so after completing baseline assessments, but before experiencing Bootle Blast. Children’s mean active playtime (i.e., mini-games targeting the UL) across the 8-weeks was 377 min, while mean total time spent engaging with Bootle Blast (active + passive play time [e.g., time navigating menus, reviewing rewards]) was 728 min. In total, eight technical issues (from five children) were reported, and all but three were resolved within 48 h. Partial effectiveness was associated with the intervention. Specifically, 85% of participants improved on the PQRS and 69% achieved clinically important improvements ≥ 2 points in performance on the COPM. Children improved by 1.8 blocks on average on the BBT, while on the CHEQ, five children had a clinically important increase of 10% of the total number of UL activities performed with both hands.ConclusionBootle Blast is a feasible and effective option to facilitate access and engage children with cerebral palsy in UL home rehabilitation.Trial registration Trial registration number: NCT05403567.

Effect of Advanced Footwear Technology Spikes on Sprint Acceleration: A Multiple N-of-1 Trial

BackgroundIn contrast with Advanced Footwear Technology-AFT running shoes for long-distance, little is known about AFT sprint spikes on performance and acceleration parameters. However, their use has become widespread since the Tokyo 2020 Olympics, and knowledge of their effects would seem to be an essential starting point before any clinical or socio-economic considerations.ObjectivesOur objectives were to determine intra- and inter-subject sprinting performance modifications with Nike® AFT spikes (NAS) compared to standard spiked-shoes (SS).MethodsHealthy regional to national sprint athletes (n = 21, ≥ 750 pts World Athletics) performed 16 repetitions of 30-m sprints with either the NAS or SS condition during a single session, based on the multiple N-of-1 method, with pairwise randomisation and double-blind procedure. Time on 30-m sprints (Stalker radar), force-velocity profile (F0, V0, Vmax, Pmax, RF, DRF and FVP slope), and confounding factors (wind and shoe mass) were measured. Statistical analyses included a mixed linear regression model for group analyses, and randomisation test inversion and non-overlap-of-all-pair (NAP) methods for intra-individual analysis.ResultsNAS improved 30-m time by a mean of − 0.02 s (SMD = 0.4, p = 0.014), with no interaction with any confounding factors. Significant changes were seen in velocity (Vmax : SMD = 0.9, p < 0.001; V0: SMD = 0.7, p < 0.001) and the horizontal ratio of force (RFmax: SMD = 0.5, p = 0.043), with no changes observed in force production. Whatever the footwear, one unit of positive wind (+ 1 m.s− 1 ) improved performance by − 0.03 s (p < 0.001). At an individual level, four athletes improved (NAP ≥ 0.69), and one had a statistical decrease in performance. Changes in F-V profiles were largely individual.ConclusionsA positive effect on sprint acceleration characteristics was observed when using Nike® AFT spikes, due to an increase in velocity and the horizontal ratio of force. A major variability in inter-individual response justifies single-case experimental designs for research on the topic.Trial Registration NumberNCT05881148.

Imbalances in Two-Level Hierarchical Linear Modeling of Single-Case Data: A Monte Carlo Simulation Study

Hierarchical linear modeling (HLM) is a promising approach that can be applied to explain variability in intervention effectiveness between participants in single-case experimental design (SCED) research. This approach allows the inclusion of participant characteristics as moderators to account for variability in intervention effectiveness. However, little is known about the performance of HLM for analysis with the inclusion of imbalanced intervention starting points and imbalanced moderators. Therefore, the goal of this study is to empirically evaluate the statistical properties of this model through a large-scale Monte Carlo simulation study under these scenarios. The results indicate that imbalanced intervention starting points have no impact on the statistical properties of estimating intervention effects. On the other hand, imbalanced moderators have an impact on estimating the intervention and moderator. How the conditions of imbalanced moderators influence the performance of two-level HLM depends on how the moderators are coded. Two general conclusions can be made. The model results in more favorable statistical properties when (i) a larger number of participants are included and (ii) the variability in continuous moderators is larger. Practical implications for the design and analysis of SCEDs are discussed.

Exploring the Effectiveness and Challenges of Community Rehabilitation Service Programs for Children with Developmental Delays: A Qualitative Study from the Perspective of Early Intervention Service Providers in Taiwan.

This qualitative study aimed to investigate the effectiveness of community rehabilitation programs for children with developmental delays from the perspective of early intervention service providers in Taiwan. Adopting a single-case experimental design (ABM design), this study examined the immediate and sustained effects of interventions on individualized goals during baseline, intervention, and maintenance phases. Additionally, data from interviews with parents, special education teachers, and other participants were collected to understand the challenges and improvement strategies of community rehabilitation programs. Results revealed that community rehabilitation programs for children with developmental delays exhibited both immediate and sustained effectiveness. Challenges faced by parents and professionals differed, with parents having less contact and communication with administrative systems, while professionals experienced more pronounced implementation difficulties during interventions. Moreover, strategies for improving community rehabilitation programs for children with developmental delays should vary for parents and professionals to address inconsistencies in attitudes and strategies among parents and administrative obstacles encountered by professionals.