Alternative Research Perspectives

Abstract

Waldron begins the final section of her letter with the claim that the data for all but 16 of the 48 children with suspected DAS should be discounted, noting that even the 16 subjects "have widely varying ages, unspecified treatment histories, and varying receptive language status." Waldron evidently views the data for the 16 children provided by the five collaborating researchers (Study 3: A–E) as valid, but not the data obtained from the samples provided by the second author (Aram & Horowitz, 1993, as cited in Shriberg et al., 1997b) or the samples provided by local clinicians (Study 2). As reviewed at the outset of the present discussion, we take a different position on both criteria for suspected DAS and on the value of subject diversity for the questions posed. What is most relevant from a scientific perspective is that even if our findings were restricted to the 16 children whom Waldron accepts as valid subjects, we submit that they would sufficiently motivate our interpretations and conclusions. The issue here appears to be a difference in perspective on the role and responsibilities of researchers. Waldron is concerned that, notwithstanding the caveats we include about threats to internal and external validity of our findings, some readers might act inappropriately in the clinic based on their interpretation of our findings. We report that inappropriate stress occurred in approximately 50% of the children with suspected DAS (whether totaling 16 or 48 children), compared to 10% of the 71 eligible children with speech delay of unknown origin. In our view, our fundamental task as researchers is to provide a clear report of our science. In turn, if sufficiently stimulating to the scientific community, the report may motivate others to attempt to replicate and explicate our findings. Finally, we respect Waldron's interest in learning how children with DAS differ from other children, but we disagree with her conclusion that studies comparing DAS with adult onset apraxia (AOS) "leads us to ask less relevant questions about children with unusual and persistent speech disorders." Perhaps the source of our difference is in alternative perceptions of how to reach the end goal of helping children, possibly including prevention. Waldron stresses the need for treatment-relevant research, noting, "In order to intervene efficiently and appropriately, we need to know whether and how children with DAS differ from other children, not how they might resemble adults with an acquired disorder." We, too, are interested in treatment, but specifically as it follows from a well-developed explanatory account of the origin and nature of the disorder (see discussion, Shriberg et al., 1997c, pp. 332–333). A possible route toward such an account is to explore the relevance of neuroscience data in adult onset speech disorders, an approach that has been productive for studying dysarthria in adults and children. As reviewed in the first and third papers, our interest in how the speech of children with suspected DAS might resemble the speech of adults with acquired apraxia addresses the hypothesis of common deficits in underlying neurolinguistic or psycholinguistic processes. A report from such a study is in preparation.