The case for treatment fidelity in active music interventions: why and how.

As the volume of studies testing the benefits of active music-making interventions increases exponentially, it is important to document what exactly is happening during music treatment sessions in order to provide evidence for the mechanisms through which music training affects other domains. Thus, to complement systematic and rigorous attention to outcomes of the treatment, we outline four vital components of treatment fidelity and discuss their implementation in nonmusic- and music-based interventions. We then describe the design of Music Impacting Language Expertise (MILEStone), a new intervention that aims to improve grammar skills in children with specific language impairment by increasing sensitivity to rhythmic structure, which may enhance general temporal processing and sensitivity to syntactic structure. We describe the approach to addressing treatment fidelity in MILEStone adapted from intervention research from other fields, including a behavioral coding system to track instructional episodes and child participation, a treatment manual, activity checklists, provider training and monitoring, a home practice log, and teacher ratings of participant engagement. This approach takes an important first step in modeling a formalized procedure for assessing treatment fidelity in active music-making intervention research, as a means of increasing methodological rigor in support of evidence-based practice in clinical and educational settings.