Toward a Model of Pediatric Speech Sound Disorders (SSD) for Differential Diagnosis and Therapy Planning

The classification and differentiation of pediatric speech sound disorders (SSD) is one of the main questions in the field of speech- and language pathology. Terms for classifying childhood and SSD and motor speech disorders (MSD) refer to speech production processes, and a variety of methods of intervention has been developed aimed at different parts of the speech production process. However, in clinical practice diagnosis is primarily based on behavioral speech symptoms rather than the underlying deficits. The diagnostic dilemma is that the ability to investigate the characteristics of subtypes of SSD requires ‘pure’ cases selected on the basis of unambiguous/clear-cut criteria, which are only available as a result of research. In this chapter we propose a process-oriented approach to diagnosis and treatment planning of pediatric SSD based on three pillars of research that will allow us to break through the circularity and bring the field a substantial step forward in the next decade. The core of this approach is a focus on underlying deficits rather than classification based on symptoms. We argue that to identify underlying deficits, one must start with a model of the cognitive and neuromotor operations involved from which specific hypotheses of speech symptoms are derived. This research methodology is implemented in the form of clinical instruments that allow for direct demonstration of the underlying deficit(s). A process-oriented diagnostic test battery as suggested here holds important advantages for the diagnosis and treatment of pediatric speech disorders and will foster the development of more targeted interventions and outcome measures. The approach is illustrated by comparing childhood apraxia of speech (CAS)m with other pediatric SSD.