Optimal intervention intensity in speech-language pathology: discoveries, challenges, and unchartered territories

This article is the final response in a scientific forum on the optimal intensity of intervention in speech-language pathology. It is a reflection on the state of knowledge offered by the 13 commentaries in this issue, addressing the areas of early communication and language impairment, speech sound disorders in children, emergent literacy, reading, aphasia, dysphagia, stuttering, motor speech disorders, voice disorders, and traumatic brain injury. Although more intense intervention can lead to better outcomes, the relationship between intensity and outcome is not always linear. More is not always better. Non-intense and intense schedules can yield similar outcomes. Intensity can also reach a point of diminishing return. The insights offered by the authors illustrate the challenges involved in studying this complex issue. To establish the optimal intensity of interventions in speech-language pathology our field needs to: identify active ingredients of interventions; better understand how principles of motor learning and neural plasticity facilitate learning; appreciate the contribution of individuals characteristics, values, and preferences; discover the effect of specific combinations of intensity (including dose, dose form, dose frequency, session duration, and total intervention duration) on treatment outcomes, and find practical solutions when disparities exist between research recommendations and workplace limitations.