Paul Petersen

The efficacy of early intervention programs for children with organic impairment: A quantitative review

Abstract The results of studies examining the effectiveness of early intervention for infants and children with organic impairment and developmental delay were reviewed using recently developed quantitative methods that treat the literature review process as a unique type of scientific inquiry. Thirty-eight studies meeting certain predetermined criteria were included in the review. The 38 studies contained a total of 118 statistical hypothesis tests that evaluated the effectiveness of early intervention. An analysis of these tests based on the calculation of effect sizes revealed that subjects receiving early intervention performed better on a wide range of dependent measures than subjects not receiving intervention. The outcomes were found to be related to several design and study characteristics. Larger effect sizes were associated with preexperimental designs, and also with studies in which the internal validity was rated as poor. Several other design variables such as how subjects were assigned to conditions and how the dependent measure was recorded were related to study outcome as measured by effect size. The conclusion was made that an accurate interpretation of the early intervention research literature cannot be made without consideration of specific design variables and study characteristics.

Quantitative Reviewing of Medical Literature An Approach to Synthesizing Research Results in Clinical Pediatrics

The quantitative literature review is presented as a unique type of research endeavor complete with formal stages that parallel those associated with primary or experimental research. This article provides a tutorial overview of the quantitative literature review procedure and, in con junction with the companion article published in this issue, serves to illustrate the application of this technique in the review process. The stages in quantitative review include: (1) problem formation; (2) data collection; (3) data evaluation; (4) analysis and interpretation; and (5) reporting results. It is argued that inferences made in the research review process are as central to the establishment of valid biomedical and clinical knowledge as inferences made in primary research. Despite some limitations, quantitative reviewing procedures constitute a significant advance over the traditional narrative methods of integrating empirical research in an area of interest. The use of quantitative reviewing procedures represents a paradigm shift in which the literature review is conceptualized as a unique form of scientific inquiry complete with formal stages and methods. The adoption of these methods should assist researchers in the behavioral and biomedical sciences in establishing scientifically valid data bases to guide theory development and direct future clinical investigation.

Home Environment and Adjustment in Families with Handicapped Children: A Canonical Correlation Study

The hypothesis that adjustment within the family of a handicapped child is due to more than just the presence of the child was investigated using canonical correlation. Five borne environment variables—handicapped-related events, resources available, severity of symptoms, other sources of stress, and socioeconomic status—and three adjustment variables—subjective assessment of the childs presence, marital adjustment, and maternal health—were used. Data were collected from 105 mothers of handicapped children. Two significant variates emerged with canonical correlations of .776 and .447. The total redundancy for the adjustment variables across both variates was .346. For the environment variables, the total redundancy was .251. The resources available and the number of handicapped-related events were the most important environment variables, and socioeconomic status was the least important.

Reducing abnormal drinking patterns in the severely disabled: a multiple baseline study

The therapeutic effectiveness of an adapted cup combined with a programme of differential reinforcement was examined in three individuals with severe developmental disabilities. A multiple baseline design across subjects was employed. The intervention programme produced a partial improvement in drinking ability for two of the subjects. One subject with extensive oral motor dysfunction did not exhibit any positive response to the intervention. The argument is made that single subject strategies can assist rehabilitation specialists in documenting clinical change for individual patients and that future research should focus on the investigation of subject characteristics that influence treatment outcome.