To test the concept of multiuser 3D virtual environments as media to teach semester-long courses, we developed a software prototype called Aeroquest. An aerospace design course--offered to 135 second-year students for university credits in Fall 2009--was divided into two groups: the real-world group attending lectures, physically, in a campus hall…

Objective: We conducted a meta-analysis of epidemiological studies investigating the association between maternal age and autism. Method: Using recommended guidelines for performing meta-analyses, we systematically selected, and extracted results from, epidemiological scientific studies reported before January 2012. We calculated pooled risk…

This article examines the effect of improvements in timing/rhythmicity on mathematics achievement. A total of 86 participants attending 1st through 4th grades completed pre- and posttest measures of mathematics achievement from the Woodcock-Johnson III Tests of Achievement. Students in the experimental group participated in a 4-week intervention…

In this article, the authors address the practicalities of how data should be presented, summarized, and interpreted. There are no exact rules; indeed there are valid concerns that exact rules may be inappropriate and too prescriptive. New procedures evolve, and new methods may be needed to deal with new types of data, just as people know that new…

This paper includes a nontechnical description of methods for calculating effect sizes in intellectual and developmental disability studies. Different hypothetical studies are used to illustrate how null hypothesis significance testing (NHST) and effect size findings can result in quite different outcomes and therefore conflicting results. Whereas…

Objective: This study was designed to extend the use of a memory training technique, known as the repetition-lag procedure, to Alzheimer patients. The specificity of this procedure is to target the process of recollection for improvement. Method: A group of 12 patients were trained individually for 6 h. The training procedure consisted of a series…

Does the choice of test for assessing reading comprehension influence the outcome of genetic analyses? A twin design compared two types of reading comprehension tests classified as primarily associated with word decoding (RC-D) or listening comprehension (RC-LC). For both types of tests, the overall genetic influence is high and nearly identical.…

Purpose: The mean length of children's utterances is a valuable estimate of their early language acquisition. The available normative data lack documentation of language and nonverbal intelligence levels of the samples. This study reports age-referenced mean length of utterance (MLU) data from children with specific language impairment (SLI) and…

Background: Clinicians rely on parents to provide information regarding the onset and development of stuttering in their own children. The accuracy and reliability of their judgments of stuttering is therefore important and is not well researched. Aim: To investigate the accuracy of parent judgements of stuttering in their own children's speech…

Standardized effect sizes and confidence intervals thereof are extremely useful devices for comparing results across different studies using scales with incommensurable units. However, exact confidence intervals for standardized effect sizes can usually be obtained only via iterative estimation procedures. The present article summarizes several…

Computer assisted psychomotor training is recognized as an appropriate tool in motor skill acquisition in adults with and without physical limitations. In specialized populations of individuals with physical deficits such as Parkinson's disease, previous researchers have examined the application of computer assisted training during upper extremity…

Background: The study is the first within trial cost analysis of direct versus indirect and individual versus group modes of speech-and-language therapy for children with primary language impairment. Aims: To compare the short-run resource consequences of the four interventions alongside the effects achieved measured by standardized scores on a…

Purpose: Previous research has demonstrated the fluency-improving effect of reducing the occurrence of short-duration, phonated intervals (PIs; approximately 30-150 ms) in individuals who stutter, prompting the hypothesis that PIs in these individuals' speech are not distributed normally, particularly in the short PI ranges. It has also been…

The role of central auditory processing in reading skill development and reading disorders is unclear. The purpose of this study was to examine whether individuals with specific reading disabilities (SRD) have deficits in processing rapidly presented, serially ordered non-speech auditory signals. To this end, we compared 12 children with SRD and…

Several research laboratories have found that instructed behavior can be less sensitive to changes in contingencies than shaped behavior. The current experiment examined whether these differences in sensitivity could be related to resistance to change. Two groups of subjects, who were matched on the basis of an initial disruption assessment, were…