Caregiver and child perspectives of wellbeing in school-age children with childhood apraxia of speech.

PURPOSE: Childhood apraxia of speech (CAS) is a communication deficit that impacts a child's overall quality of life, including their academic and social interactions, yet few studies have investigated the impact from the child's perspective. Using The World Health Organization's International Classification of Functioning, Disability, and Health (ICF) framework, we examined the children's and caregivers' perspectives on the impact of CAS on their overall wellbeing. METHOD: Survey data were collected from 32 child-caregiver dyads for children ages 9-17 years with CAS. Items elicited responses along a 5-point scale to examine the perceived impact of children's speech impairments using the framework, including impact on communication, interpersonal interactions/relationships, and major life events. RESULT: Results from non-parametric statistical analyses revealed: (a) caregivers reported a significantly greater impact than children across individual ICF domains; (b) child responses were not significantly correlated with their caregiver's responses or with the child's age, gender, or severity indicators; and (c) both caregivers and children indicated the domain of communication was impacted more than other domains. CONCLUSION: Results suggest a potential disconnect in the perceived impact of CAS between the caregiver and child. Recommendations include facilitating a dialogue between the child-caregiver dyad and considering treatment goals that address wellbeing.

Evaluating acoustic representations and normalization for rhoticity classification in children with speech sound disorders.

The effects of different acoustic representations and normalizations were compared for classifiers predicting perception of children's rhotic versus derhotic /ɹ/. Formant and Mel frequency cepstral coefficient (MFCC) representations for 350 speakers were z-standardized, either relative to values in the same utterance or age-and-sex data for typical /ɹ/. Statistical modeling indicated age-and-sex normalization significantly increased classifier performances. Clinically interpretable formants performed similarly to MFCCs and were endorsed for deep neural network engineering, achieving mean test-participant-specific F1-score = 0.81 after personalization and replication (σx = 0.10, med = 0.83, n = 48). Shapley additive explanations analysis indicated the third formant most influenced fully rhotic predictions.

Comparing online versus laboratory measures of speech perception in older children and adolescents.

Given the increasing prevalence of online data collection, it is important to know how behavioral data obtained online compare to samples collected in the laboratory. This study compares online and in-person measurement of speech perception in older children and adolescents. Speech perception is important for assessment and treatment planning in speech-language pathology; we focus on the American English /ɹ/ sound because of its frequency as a clinical target. Two speech perception tasks were adapted for web presentation using Gorilla: identification of items along a synthetic continuum from rake to wake, and category goodness judgment of English /ɹ/ sounds in words produced by various talkers with and without speech sound disorder. Fifty typical children aged 9-15 completed these tasks online using a standard headset. These data were compared to a previous sample of 98 typical children aged 9-15 who completed the same tasks in the lab setting. For the identification task, participants exhibited smaller boundary widths (suggestive of more acute perception) in the in-person setting relative to the online setting. For the category goodness judgment task, there was no statistically significant effect of modality. The correlation between scores on the two tasks was significant in the online setting but not in the in-person setting, but the difference in correlation strength was not statistically significant. Overall, our findings agree with previous research in suggesting that online and in-person data collection do not yield identical results, but the two contexts tend to support the same broad conclusions. In addition, these results suggest that online data collection can make it easier for researchers connect with a more representative sample of participants.

Preliminary Speech Perception Performance Profiles of School-Age Children With Childhood Apraxia of Speech, Speech Sound Disorder, and Typical Development.

PURPOSE: Limited research exists assessing speech perception in school-age children with speech sound disorder (SSD) and childhood apraxia of speech (CAS); despite early evidence that speech perception may lead to error-prone motor planning/programming. In this study, we examine speech perception performance in school-age children with and without speech production deficits. METHOD: Speech perception was assessed using the Wide Range Acoustic Accuracy Scale to determine the just-noticeable difference in discrimination for three consonant-vowel syllable contrasts (/bɑ/-/wɑ/, /dɑ/-/gɑ/, /ɹɑ/-/wɑ/), each varying along a single acoustic parameter for seven children with CAS with rhotic errors, seven children with SSD with rhotic errors, and seven typically developing (TD) children. RESULTS: Findings revealed statistically significant mean differences between perceptual performance of children with CAS when compared to TD children for discrimination of /ɹɑ/-/wɑ/ contrasts. Large effect sizes were also observed for comparisons of /ɹɑ/-/wɑ/ contrasts between children with CAS, SSD, and TD peers. Additionally, large effect sizes were observed for /dɑ/-/gɑ/ contrasts between children with CAS and SSD and TD children despite nonsignificant mean differences in group performance. CONCLUSIONS: Overall, mean outcome scores suggest that school-age children with CAS and persistent rhotic errors demonstrated less accurate speech perception skills relative to TD children for the /ɹɑ/-/wɑ/ contrasts. However, the relatively small sample sizes per group limit the extent to which these findings may be generalized to the broader population.

Reproducible Speech Research With the Artificial Intelligence-Ready PERCEPT Corpora.

BACKGROUND: Publicly available speech corpora facilitate reproducible research by providing open-access data for participants who have consented/assented to data sharing among different research teams. Such corpora can also support clinical education, including perceptual training and training in the use of speech analysis tools. PURPOSE: In this research note, we introduce the PERCEPT (Perceptual Error Rating for the Clinical Evaluation of Phonetic Targets) corpora, PERCEPT-R (Rhotics) and PERCEPT-GFTA (Goldman-Fristoe Test of Articulation), which together contain over 36 hr of speech audio (> 125,000 syllable, word, and phrase utterances) from children, adolescents, and young adults aged 6-24 years with speech sound disorder (primarily residual speech sound disorders impacting /ɹ/) and age-matched peers. We highlight PhonBank as the repository for the corpora and demonstrate use of the associated speech analysis software, Phon, to query PERCEPT-R. A worked example of research with PERCEPT-R, suitable for clinical education and research training, is included as an appendix. Support for end users and information/descriptive statistics for future releases of the PERCEPT corpora can be found in a dedicated Slack channel. Finally, we discuss the potential for PERCEPT corpora to support the training of artificial intelligence clinical speech technology appropriate for use with children with speech sound disorders, the development of which has historically been constrained by the limited representation of either children or individuals with speech impairments in publicly available training corpora. CONCLUSIONS: We demonstrate the use of PERCEPT corpora, PhonBank, and Phon for clinical training and research questions appropriate to child citation speech. Increased use of these tools has the potential to enhance reproducibility in the study of speech development and disorders.

Auditory and Somatosensory Development for Speech in Later Childhood.

PURPOSE: This study collected measures of auditory-perceptual and oral somatosensory acuity in typically developing children and adolescents aged 9-15 years. We aimed to establish reference data that can be used as a point of comparison for individuals with residual speech sound disorder (RSSD), especially for RSSD affecting American English rhotics. We examined concurrent validity between tasks and hypothesized that performance on at least some tasks would show a significant association with age, reflecting ongoing refinement of sensory function in later childhood. We also tested for an inverse relationship between performance on auditory and somatosensory tasks, which would support the hypothesis of a trade-off between sensory domains. METHOD: Ninety-eight children completed three auditory-perceptual tasks (identification and discrimination of stimuli from a "rake"-"wake" continuum and category goodness judgment for naturally produced words containing rhotics) and three oral somatosensory tasks (bite block with auditory masking, oral stereognosis, and articulatory awareness, which involved explicit judgments of relative tongue position for different speech sounds). Pairwise associations were examined between tasks within each domain and between task performance and age. Composite measures of auditory-perceptual and somatosensory functions were used to investigate the possibility of a sensory trade-off. RESULTS: Statistically significant associations were observed between the identification and discrimination tasks and the bite block and articulatory awareness tasks. In addition, significant associations with age were found for the category goodness and bite block tasks. There was no statistically significant evidence of a trade-off between auditory-perceptual and somatosensory domains. CONCLUSIONS: This study provided a multidimensional characterization of speech-related sensory function in older children/adolescents. Complete materials to administer all experimental tasks have been shared, along with measures of central tendency and dispersion for scores in two subgroups of age. Ultimately, we hope to apply this information to make customized treatment recommendations for children with RSSD based on sensory profiles.

Tutorial: Using Visual-Acoustic Biofeedback for Speech Sound Training.

PURPOSE: This tutorial summarizes current practices using visual-acoustic biofeedback (VAB) treatment to improve speech outcomes for individuals with speech sound difficulties. Clinical strategies will focus on residual distortions of /ɹ/. METHOD: Summary evidence related to the characteristics of VAB and the populations that may benefit from this treatment are reviewed. Guidelines are provided for clinicians on how to use VAB with clients to identify and modify their productions to match an acoustic representation. The clinical application of a linear predictive coding spectrum is emphasized. RESULTS: Successful use of VAB requires several key factors including clinician and client comprehension of the acoustic representation, appropriate acoustic target and template selection, as well as appropriate selection of articulatory strategies, practice schedules, and feedback models to scaffold acquisition of new speech sounds. CONCLUSION: Integrating a VAB component in clinical practice offers additional intervention options for individuals with speech sound difficulties and often facilitates improved speech sound acquisition and generalization outcomes. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.21817722.

Traditional and Visual-Acoustic Biofeedback Treatment via Telepractice for Residual Speech Sound Disorders Affecting /ɹ/: Pilot study.

Purpose: This study aimed to examine the feasibility of telepractice delivery of a treatment package including visual-acoustic biofeedback and motor-based treatment for residual speech sound disorder affecting /ɹ/ in school-age children. The overall study used a single-case randomization design; however, this preliminary report will simply quantify changes in accuracy before and after completion of the treatment package. The present analysis did not differentiate between the relative contributions of biofeedback and motor-based treatments. Method: Seven children aged 9-14 received speech therapy for /ɹ/ distortions via telepractice. The study design consisted of three phases: baseline (four sessions), treatment (20 sessions), and post-treatment (three sessions). Treatment included two sessions weekly for a duration of 10 weeks. The participants received one motor-based/non-biofeedback session and one visual-acoustic biofeedback session per week. The order of treatment within each week was randomly determined prior to the start of therapy. Overall progress was assessed using untrained listeners' ratings of word probes administered in the baseline and posttreatment phases. Results: Findings revealed that six of the seven participants showed a clinically significant response to the overall treatment package, although the magnitude of individual responses varied across speech contexts (consonantal and vocalic) and participants. Conclusion: The present results suggest that a treatment combining visual-acoustic biofeedback and motor-based treatment for residual /ɹ/ errors treatment can be effectively delivered via telepractice. Considerations for technology setup and treatment protocols are provided.

Clinical Considerations for Speech Perception in School-Age Children With Speech Sound Disorders: A Review of the Current Literature.

PURPOSE: The purpose of this study was to synthesize the methodological variability in the speech perception literature for school-age children with residual speech sound disorder (RSSD), with the primary intention of using the existing knowledge to inform clinical decisions and optimize treatment outcomes for children. METHOD: Ten electronic databases were systematically searched to identify articles examining the speech perception skills of school-age children with RSSD. A total of 11 articles met inclusion criteria, reporting of methodological characteristics was rated and compared across studies, and findings were summarized. RESULTS: The majority of studies reviewed here confirmed the presence of a perceptual deficit for a subset of children with RSSD. However, marked variability across study methodologies limits clinical interpretation and application of the findings. CONCLUSIONS: Despite limited research in children with RSSD and wide variability across study procedures, stimulus type, perception type, and task type emerged as potential key factors that provide critical insight into a child's perceptual skill. The current evidence suggests that deficits in speech perception may significantly impact acquisition of accurate phoneme production for children with RSSD. Furthermore, these findings suggest that assessment and treatment of speech perception may be a critical component of an intervention program for school-age children, although further research is needed to determine effective clinical procedures.

Adult perception of stop consonant voicing in American-English-learning toddlers: Voice onset time and secondary cues.

Most studies of speech perception employ highly controlled stimuli. It is not always clear how such results extend to the processing of natural speech. In a series of experiments, we progressively explored the role of voice onset time (VOT) and potential secondary cues in adult labeling of stressed syllable-initial /b d p t/ produced by typically developing two-year-old learners of American English. Taken together, the results show the following: (a) Adult listeners show phoneme boundaries in labeling functions comparable to what have been established for adult speech. (b) Adult listeners can be sensitive to distributional properties of the stimulus set, even in a study that employs highly varied naturalistic productions from multiple speakers. (c) Secondary cues are available in the speech of two-year-olds, and these may influence listener judgments. Cues may differ across places of articulation and the VOT continuum. These results can lend insight into how clinicians judge child speech during assessment and also have implications for our understanding of the role of primary and secondary acoustic cues in adult perception of child speech.

Comparing Biofeedback Types for Children With Residual /ɹ/ Errors in American English: A Single-Case Randomization Design.

Purpose Research comparing different biofeedback types could lead to individualized treatments for those with residual speech errors. This study examines within-treatment response to ultrasound and visual-acoustic biofeedback, as well as generalization to untrained words, for errors affecting the American English rhotic /ɹ/. We investigated whether some children demonstrated greater improvement in /ɹ/ during ultrasound or visual-acoustic biofeedback. Each participant received both biofeedback types. Individual predictors of treatment response (i.e., age, auditory-perceptual skill, oral somatosensory skill, and growth mindset) were also explored. Method Seven children ages 9-16 years with residual rhotic errors participated in 10 treatment visits. Each visit consisted of two conditions: 45 min of ultrasound biofeedback and 45 min of visual-acoustic biofeedback. The order of biofeedback conditions was randomized within a single-case experimental design. Acquisition of /ɹ/ was evaluated through acoustic measurements (normalized F3-F2 difference) of selected nonbiofeedback productions during practice. Generalization of /ɹ/ was evaluated through acoustic measurements and perceptual ratings of pretreatment/posttreatment probes. Results Five participants demonstrated acquisition of practiced words during the combined treatment package. Three participants demonstrated a clinically significant degree of generalization to untreated words on posttreatment probes. Randomization tests indicated one participant demonstrated a significant advantage for visual-acoustic over ultrasound biofeedback. Participants' auditory-perceptual acuity on an /ɹ/-/w/ identification task was identified as a possible correlate of generalization following treatment. Conclusions Most participants did not demonstrate a statistically significant difference in acoustic productions between the ultrasound and visual-acoustic conditions, but one participant showed greater improvement in /ɹ/ during visual-acoustic biofeedback. Supplemental Material https://doi.org/10.23641/asha.14881101.

Associations Between Speech Perception, Vocabulary, and Phonological Awareness Skill in School-Aged Children With Speech Sound Disorders.

Purpose Prior studies report conflicting descriptions of the relationships between phonological awareness (PA), vocabulary, and speech perception in preschoolers with speech disorders. This study sought to determine the nature of these relationships in a sample of school-aged children with residual speech sound errors affecting /ɹ/. Method Participants included 110 children aged 7;0-17;4 (years;months) with residual errors impacting /ɹ/. Data on perceptual acuity and perceptual bias in an /ɹ/ identification task, receptive vocabulary, and PA were obtained. A theoretically and empirically motivated path model was constructed with vocabulary mediating the relationship between two measures of speech perception and PA. Model parameters were determined through maximum likelihood estimation with standard errors that were robust to nonnormality. Monte Carlo simulation was used to examine achieved power at the current sample size. Results The saturated path model explained 19% of the variance in PA. The direct path between age-adjusted perceptual acuity and PA was significant, as was the direct path between vocabulary and PA. Contrary to our hypothesis, there was no evidence in the current sample that vocabulary skill mediated the relationship between speech perception and PA. Each individual path was adequately powered at the current sample size. Conclusions The overall model provided evidence for a continued relationship between speech perception, measured by perceptual acuity of the sound in error, and PA in school-aged children with residual speech errors. Thus, measures of speech perception remain relevant to the assessment of school-aged children and adolescents in this population. Supplemental Material https://doi.org/10.23641/asha.13641275.

Computer-assisted challenge point intervention for residual speech errors.

Purpose: This preliminary case series investigated the effects of biofeedback intervention for residual rhotic errors delivered within a modified challenge point framework. In the challenge point framework, practice difficulty is adaptively adjusted with the goal of enhancing generalization learning. This study more specifically evaluated the feasibility of a computer-mediated implementation of challenge point treatment for rhotic errors using a custom open-source software, the Challenge Point Program (CPP). Method: Participants were five native English speakers, ages 7;3-15;5, who had established but not generalized correct rhotic production in previous treatment; overall treatment duration was flexible. Treatment incorporated either electropalatographic or visual-acoustic biofeedback and was structured by challenge point principles implemented using the CPP software. Results: Participants were highly variable in the magnitude of generalization gains attained. However, the median overall effect size was 4.24, suggesting that participants' response in treatment tended to exceed the minimum value considered clinically significant. Conclusions: These findings provide preliminary evidence that computer-mediated implementation of the challenge point framework can be effective in producing generalization in some participants.

Tutorial: Motor-Based Treatment Strategies for /r/ Distortions.

Purpose This tutorial summarizes current best practices in treating American English /r/ distortions in children with residual speech errors. Method To enhance the effectiveness of clinicians' cueing and feedback, the phonetics of /r/ production is reviewed. Principles of acquisition, which can inform how to practice /r/ in the early stages of therapy, are explained. Elements of therapy that lack scientific support are also mentioned. Results Although there is significant variability in /r/ production, the common articulatory requirements include an oral constriction, a pharyngeal constriction, tongue body lowering, lateral bracing, and slight lip rounding. Examples of phonetic cues and shaping strategies are provided to help clinicians elicit these movements to evoke correct /r/ productions. Principles of acquisition (e.g., blocked practice, frequent knowledge of performance feedback) are reviewed to help clinicians structure the earliest stages of treatment to establish /r/. Examples of approaches that currently lack scientific support include nonspeech oral motor exercises, tactile cues along the mylohyoid muscle, and heterogeneous groupings in group therapy. Conclusion Treatment strategies informed by phonetic science and motor learning theory can be implemented by all clinicians to enhance acquisition of /r/ for children with residual errors. Supplemental Material https://doi.org/10.23641/asha.12771329.

Auditory Perception and Ultrasound Biofeedback Treatment Outcomes for Children With Residual /ɹ/ Distortions: A Randomized Controlled Trial.

Purpose This study evaluated whether outcomes from treatment, which includes ultrasound visual feedback (UVF), would be more or less effective when combined with auditory perception training for children with residual /ɹ/ errors. Method Children ages 8-16 years with /ɹ/ distortions participated in speech therapy that included real-time UVF of the tongue. Thirty-eight participants were randomized to speech therapy conditions that included a primary focus on articulation using UVF or a condition that included auditory perceptual training plus UVF (incorporating category goodness judgments and self-monitoring). Generalization of /ɹ/ production accuracy to untrained words was assessed before and after 14 hr of therapy. Additionally, the role of auditory perceptual acuity was explored using a synthetic /ɹ/-/w/ continuum. Results There was no difference between the treatment groups in rate of improvement of /ɹ/ accuracy (increase of 34% for each group; p = .95, ηp2 = .00). However, pretreatment auditory acuity was associated with treatment progress in both groups, with finer perceptual acuity corresponding to greater progress (p = .015, ηp2 = .182). Conclusion Similar gains in speech sound accuracy can be made with treatment that includes UVF with or without auditory perceptual training. Fine-grained perceptual acuity may be a prognostic indicator with treatment. Supplemental Material https://doi.org/10.23641/asha.11886219.

Protocol for Correcting Residual Errors with Spectral, ULtrasound, Traditional Speech therapy Randomized Controlled Trial (C-RESULTS RCT).

BACKGROUND: Speech sound disorder in childhood poses a barrier to academic and social participation, with potentially lifelong consequences for educational and occupational outcomes. While most speech errors resolve by the late school-age years, between 2 and 5% of speakers exhibit residual speech errors (RSE) that persist through adolescence or even adulthood. Previous findings from small-scale studies suggest that interventions incorporating visual biofeedback can outperform traditional motor-based treatment approaches for children with RSE, but this question has not been investigated in a well-powered randomized controlled trial. METHODS/DESIGN: This project, Correcting Residual Errors with Spectral, ULtrasound, Traditional Speech therapy Randomized Controlled Trial (C-RESULTS RCT), aims to treat 110 children in a parallel randomized controlled clinical trial comparing biofeedback and non-biofeedback interventions for RSE affecting the North American English rhotic sound /ɹ/. Eligible children will be American English speakers, aged 9-15 years, who exhibit RSE affecting /ɹ/ but otherwise show typical cognitive-linguistic and hearing abilities. Participants will be randomized, with stratification by site (Syracuse University or Montclair State University) and pre-treatment speech production ability, to receive either a motor-based treatment consistent with current best practices in speech therapy (40% of participants) or treatment incorporating visual biofeedback (60% of participants). Within the biofeedback condition, participants will be assigned in equal numbers to receive biofeedback in the form of a real-time visual display of the acoustic signal of speech or ultrasound imaging of the tongue during speech. The primary outcome measure will assess changes in the acoustics of children's production of /ɹ/ during treatment, while a secondary outcome measure will use blinded listeners to evaluate changes in the perceived accuracy of /ɹ/ production after the completion of all treatment. These measures will allow the treatment conditions to be compared with respect to both efficacy and efficiency. DISCUSSION: By conducting the first well-powered randomized controlled trial comparing treatment with and without biofeedback, this study aims to provide high-quality evidence to guide treatment decisions for children with RSE. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT03737318, November 9, 2018.

Speech Sound Disorder and Visual Biofeedback Intervention: A Preliminary Investigation of Treatment Intensity.

A growing body of research suggests that cases of speech sound errors that have not responded to previous intervention can sometimes be eliminated through speech therapy incorporating visual biofeedback. Aside from considerations related to the specific biofeedback type, acquisition and generalization of a motor plan may be linked to treatment intensity. Several researchers have raised the possibility that inadequate dosage levels may present a significant barrier to success. Thus, the current study aimed to assess the relationship between treatment intensity and treatment outcomes. Twenty-nine articles reporting the use of visual biofeedback intervention for speech sound disorder were identified and coded for treatment intensity using the cumulative intervention index and outcomes using mean level difference scores. Findings reveal small but significant relationships between measures of treatment intensity and efficacy, which should be interpreted with caution given the preliminary nature of this review. Further research in this area is necessary, as inconsistencies in reporting intensity and outcomes across studies underscore the need for more systematic terminology and reporting methods.

Selecting an acoustic correlate for automated measurement of American English rhotic production in children.

Purpose: A current need in the field of speech-language pathology is the development of reliable and efficient techniques to evaluate accuracy of speech targets over the course of treatment. As acoustic measurement techniques improve, it should become possible to use automated scoring in lieu of ratings from a trained clinician in some contexts. This study asks which acoustic measures correspond most closely with expert ratings of children's productions of American English /ɹ/ in an effort to develop an automated scoring algorithm for use in treatment targeting rhotics. Method: A series of ordinal mixed-effects regression models were fit over a large sample of children's productions of words containing /ɹ/ that had previously been rated by three trained clinicians. Akaike/Bayesian Information Criteria were used to select the best-fitting model. Result: Controlling for age, sex, and allophonic contextual differences, the measure that accounted for the most variance in speech rating was F3-F2 distance normalised relative to a sample of age- and sex-matched speakers. Conclusion: We recommend this acoustic measure for use in future automated scoring of children's production of American English rhotics. We also suggest that computer-based treatment with automated scoring should facilitate increases in treatment dosage by improving options for home practice.

Efficacy of Electropalatography for Treating Misarticulation of /r/.

PURPOSE: The purpose of the present study was to document the efficacy of electropalatography (EPG) for the treatment of rhotic errors in school-age children. Despite a growing body of literature using EPG for the treatment of speech sound errors, there is little systematic evidence about the relative efficacy of EPG for rhotic errors. METHOD: Participants were 5 English-speaking children aged 6;10 to 9;10, who produced /r/ at the word level with < 30% accuracy but otherwise showed typical speech, language, and hearing abilities. Therapy was delivered in twice-weekly 30-min sessions for 8 weeks. RESULTS: Four out of 5 participants were successful in achieving perceptually and acoustically accurate /r/ productions during within-treatment trials. Two participants demonstrated generalization of /r/ productions to nontreated targets, per blinded listener ratings. CONCLUSIONS: The present findings support the hypothesis that EPG can improve production accuracy in some children with rhotic errors. However, the utility of EPG is likely to remain variable across individuals. For rhotics, EPG training emphasizes one possible tongue configuration consistent with accurate rhotic production (lateral tongue contact). Although some speakers respond well to this cue, the narrow focus may limit lingual exploration of other acceptable tongue shapes known to facilitate rhotic productions.

Masked Visual Analysis: Minimizing Type I Error in Visually Guided Single-Case Design for Communication Disorders.

Purpose: Single-case experimental designs are widely used to study interventions for communication disorders. Traditionally, single-case experiments follow a response-guided approach, where design decisions during the study are based on participants' observed patterns of behavior. However, this approach has been criticized for its high rate of Type I error. In masked visual analysis (MVA), response-guided decisions are made by a researcher who is blinded to participants' identities and treatment assignments. MVA also makes it possible to conduct a hypothesis test assessing the significance of treatment effects. Method: This tutorial describes the principles of MVA, including both how experiments can be set up and how results can be used for hypothesis testing. We then report a case study showing how MVA was deployed in a multiple-baseline across-subjects study investigating treatment for residual errors affecting rhotics. Strengths and weaknesses of MVA are discussed. Conclusions: Given their important role in the evidence base that informs clinical decision making, it is critical for single-case experimental studies to be conducted in a way that allows researchers to draw valid inferences. As a method that can increase the rigor of single-case studies while preserving the benefits of a response-guided approach, MVA warrants expanded attention from researchers in communication disorders.