Leija V. McReynolds

Flexibility of Single-Subject Experimental Designs. Part I: Review of the Basics of Single-Subject Designs

The discussion in this article is directed at a brief review of the basic components of single-subject experimental designs. It sets out to present some of the technical and practical advantages in developing single-subject designs to evaluate potential treatment variables and treatments. The point is made that the designs are specifically structured for applied, intervention research. In addition to explaining how the basic AB components function to allow for a controlled evaluation, a short review is included of other factors important to the scientific method such as operational definitions, reliability, repeated measures, and internal and external validity. The article serves as a foundation for the following two articles that are directed at demonstrating the flexibility of single-subject experimental studies.

Generalization of correct articulation in clusters

Cluster Reduction is purported to be a general phonological process applied by misarticulating children to simplify production of the two consonants in a cluster. In this study the generality of the process was explored in six misarticulating children. The children produced errors on all /s/ and /r/ or /l/ clusters in baseline. In a counterbalanced order three children were trained on /s/ clusters first and /r/ or /l/ clusters second in a multiple baseline design; whereas three children received training on /r/ clusters first and /s/ clusters second. Generalization to other forms of /s/ and /r/ or /l/ clusters was tested throughout training. Results showed that with one exception children generalized to within class clusters but not to across class clusters. It was concluded that if cluster error patterns reflect processes, the processes are not general enough to operate across classes, but rather, are confined to the cluster receiving training.

The generalization hypothesis: final consonant deletion.

The purpose of this study was to examine the organization inherent in childrens misarticulations of final consonant sounds. Four children with consistent omission of final consonants were taught to produce selected exemplars of either final stops or fricatives in a counterbalanced order within a multiple baseline design. Generalization across sound classes was tested. The results indicated that generalization was lawful but restricted to the class of sounds being taught (either stops or fricatives) and did not extend across sound categories. The examination of individual lexical items over time showed variations which seemed to reflect the active role of children during the learning process.

Articulation Generalization During Articulation Training

Four children who misarticulated the /s/ phoneme were administered an articulation training programme which trained the child to emit the correct /s/ in isolation and in the initial, final and medial positions in nonsense syllables. Transfer of the correct /s/ was tested throughout training to determine if generalization of the trained response to untrained contexts assumes an orderly pattern of progress. Indications from the test probes were that (1) transfer of the correct articulation to untrained contexts begins when the /s/ is trained in the context of other phonemes, (2) that transfer increases rapidly when children are required to monitor the accuracy of their own articulation and (3) that generalization is influenced by shifting the position of the correct articulation within the context of the training item. Reasons for the lack of an orderly pattern of generalization acquisition are presented.

Functional Articulation Disorders: Preliminaries to Treatment

Publisher Summary This chapter discusses functional articulation disorders. An ideal definition of articulation disorder would be operational and would reflect the psychological reality of the problem as it influences the speaker and as it is perceived by listeners. It would reflect scientific knowledge about matters such as articulatory movements including coarticulation and the physiological mechanisms that support them. It would encompass phonological development and patterns. Speech pathologists concerned with treatment of disordered articulation may be troubled by expanding knowledge that is cumbersome to learn. Where clinicians once learned procedures for delivery to patients, they now must also understand those services relative to scientific knowledge concerning speech production, speech perception, linguistics, learning, scientific standards of evidence, and many other issues. Speech pathology has tended to accept authority as a source of clinical knowledge—the more remote the authority from the study of speech disorders, the greater its prestige.

Generalization in articulation training

Abstract Articulation generalization has been studied with a variety of experimental designs and procedures. Variables explored have included the contexts of training and generalization items, and other settings and individuals. Experimental studies of articulation generalization were reviewed in this article with the intent of extracting training principles relevant to obtaining generalization during articulation training. Briefly, important variables appear to include feature similarity across error sounds, training the target sound imitatively in a simple linguistic context initially, perferably in nonsense syllables, and a gradual increase in the spontaneity and complexity of the verbal unit in which a target sound is produced. In planning a remediation program of articulation training, it is important to consider childrens error patterns and their responses to various procedures in order to design individual programs for each child.

An experimental analysis of children's generalization during lexical learning: Comprehension or production

The relationship between comprehension language training and production language training was examined by teaching 12 adults and 12 children a miniature language. The relationship between the two types of training was determined by examining their effects on the generalization of names. The results indicate that production training generalizes more extensively than comprehension training. The advantages and disadvantages of both types of training are discussed.

Generalization During Speech Sound Discrimination Training

An experiment was conducted to determine whether training discrimination of a phoneme in one position in a context results in children responding to the phoneme when it is presented in other positions in contexts. Five subjects were trained to respond correctly to a phoneme in the initial, final and medial positions in a context in three progressive phases of training. At the conclusion of each training phase the remaining two positions were tested. Results showed that the subjects generalized from initial position training to the final position. The two positions were more likely to function as members of one class of stimuli, whereas the medial position functioned more nearly like a discrete and separate class of stimuli.

Final consonant generalization in hearing impaired children's articulation

Abstract Within a multiple baseline across behaviors design, four hearing impaired children who initially omitted final consonants in words were taught to produce final |k| and |v| in a contrast training procedure. Generalization of the two sounds and their cognates, the |g| and |f|, was tested to items consisting of spontaneously produced single words (naming pictures) and the same words in sentences read by the children. Results showed that the children generalized both final target sounds to a high degree in both contexts. Some generalization also occurred to the cognates which had never been trained. Although individual variability was observed, data showed that the |v| generalized to a greater number of items than the |k|, and possibly, required less training. Generalization to the |f| items was also better than to the |g| items. Response patterns suggested that final consonant production had been thoroughly acquired since variables that could have disrupted or interfered with generalization had no effect on the childrens performance.