This paper reviews whether Rett syndrome is a subtype of pervasive developmental disorders (PDD). The paper analyzes internal and external diagnostic validity and discusses whether Rett syndrome is a neurological disorder or a mental disorder. The paper concludes that data support the idea of classifying Rett syndrome as a subtype of PDD.…

This study assessed the criterion validity of the photographic adaptive communication device (ACD) used in Oklahoma to interview individuals with developmental disabilities receiving services. The back-translation process identified photographs that were frequently incorrectly identified resulting in revision of the ACD for greater validity.…

A conceptual model of quality of life, developed at the Centre for Health Promotion at the University of Toronto (Canada), and associated instrumentation for collecting data from persons with developmental disabilities are presented. Results from a preliminary study with 41 participants support the reliability and validity of the model's…

This meta-analysis of the developmental disabilities literature on remediation of problem behaviors evaluated relations between standards of practice, intervention and participant characteristics, and treatment validity. Results largely failed to support widespread assumptions of clinical practice such as the superiority of more intrusive…

Potential individual variations in the effectiveness of facilitated communication (FC) were examined with 20 students with autism and related disorders. Use of multiple methods (including auditory or visual input, simple point responses, and typing) provided no clear support for validity of FC over students' independent communication. Increased…