Motor-Based Intervention Protocols in Treatment of Childhood Apraxia of Speech (CAS)

Findings from the contemporary psychological and movement science literature that appear to have implications for medical training are reviewed. Specifically, the review focuses on four factors that have been shown to enhance the learning of motor skills: observational practice; the learner's focus of attention; feedback, and self-controlled practice. Observation of others, particularly when it is combined with physical practice, can make important contributions to learning. This includes dyad practice (i.e. practice in pairs), which is not only cost-effective, but can also enhance learning. Studies examining the role of the performer's focus of attention have consistently demonstrated that instructions inducing an external focus (directed at the movement effect) are more effective than those promoting an internal focus (directed at the performer's body movements). An external focus facilitates automaticity in motor control and promotes movement efficiency. Feedback not only has an informational function, but also has motivational properties that have an important influence on learning. For example, feedback after successful trials and social-comparative (normative) feedback indicating better than average performance have been shown to have a beneficial effect on learning. SELF-CONTROLLED PRACTICE: Self-controlled practice, including feedback and model demonstrations controlled by the learner, has been found to be more effective than externally controlled practice conditions. All factors reviewed in this article appear to have both informational and motivational influences on learning. The findings seem to reflect general learning principles and are assumed to have relatively broad applicability. Therefore, the consideration of these factors in designing procedures for medical training has the potential to enhance the effectiveness and efficiency of training.

We review research related to the learning of complex motor skills with respect to principles developed on the basis of simple skill learning. Although some factors seem to have opposite effects on the learning of simple and of complex skills, other factors appear to be relevant mainly for the learning of more complex skills. We interpret these apparently contradictory findings as suggesting that situations with low processing demands benefit from practice conditions that increase the load and challenge the performer, whereas practice conditions that result in extremely high load should benefit from conditions that reduce the load to more manageable levels. The findings reviewed here call into question the generalizability of results from studies using simple laboratory tasks to the learning of complex motor skills. They also demonstrate the need to use more complex skills in motor-learning research in order to gain further insights into the learning process.

Research in developmental phonological disorders, particularly emerging subgroup studies using behavioral and molecular genetics, requires qualitative and continuous measurement systems that meet a variety of substantive and psychometric assumptions. This paper reviews relevant issues underlying such needs and presents four measurement proposals developed expressly for causal-correlates research. The primary qualitative system is the Speech Disorders Classification System (SDCS), a 10-category nosology for dichotomous and hierarchical polychotomous classification of speech disorders from 2 years of age through adulthood. The three quantitative measures for segmental and suprasegmental analyses are (a) the Articulation Competence Index (ACI), an interval-level severity index that adjusts a subject's Percentage of Consonants Correct (PCC) score for the relative percentage of distortion errors; (b) Speech Profiles, a series of graphic-numeric displays that profile a subject's or group's severity-adjusted consonant and vowel-diphthong mastery and error patterns; and (c) the Prosody-Voice Profile, a graphic-numeric display that profiles a subject's or group's status on six suprasegmental domains divided into 31 types of inappropriate prosody-voice codes. All data for the four measures are derived from one sample of conversational speech, which obviates the limitations of citation-form testing; enables speech assessment as a qualitative, semi-continuous, and continuous trait over the life span; and provides a context for univariate and multivariate statistical analyses of phonetic, phonologic, prosodic, and language variables in multiage, multidialectal, and multicultural populations. Rationale, procedures, validity data, and examples of uses for each measure are presented.