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D Duncan

Publications and source records attributed to D Duncan.

106 records · Page 6Linked to original sources
PubMedDate not supplied

Estimating the accident potential of an Ontario driver.

To run a "demerit point" program, one uses routinely available information about drivers to identify those who are most likely to have an accident in the near future. On the basis of a four-year record for a large sample of Ontario drivers, we have examined several tools for the identification of such drivers and investigated how they perform. Each driver is thought to have an expected number of accidents, m. In a group of drivers with common traits (such as age, gender, record of convictions and accidents) the ms have a mean E(m) and a variance VAR(m). Estimates of E(m) and VAR(m) for all combinations of traits can be obtained within the framework of a multivariate statistical model. The same estimates can then be used to judge how well a model identifies drivers who have a large m. In such a multivariate model it is important to use data about previous accidents and convictions. However, the accuracy with which the m of a driver can be estimated is not improved much by distinguishing between offence type or between accidents as being "at fault" or "not at fault". Without much loss in estimation accuracy, one may attach a weight 1 to a conviction and 2 to an accident. Model performance is described in tangible terms: how many accidents are recorded by the drivers identified by a model, what proportion of identified drivers are "false positives," how many drivers with high m remain unidentified. We conclude that by using a multivariate statistical model one can do substantially better than by using a demerit point scheme in which points are assigned to offenses on the basis of their perceived seriousness. However, even when the best model is used to identify a large group of drivers, many will be false positives.

Accidents, Traffic↗
PubMedDate not supplied

Characteristics of stereotypic movement disorder and self-injurious behavior assessed with the Diagnostic Assessment for the Severely Handicapped (DASH-II).

The first experiment involved 143 individuals with severe and profound mental retardation. Individuals with Stereotypic Movement Disorder, Self-Injurious Behavior (SIB), and Stereotypic movement disorder with self-injurious behavior as assessed by the Diagnostic Assessment for the Severely Handicapped-II DASH-II were validated against Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV; American Psychiatric Association, 1994) criteria. In a second study DASH-II scores for 1480 individuals with severe and profound mental retardation were compared on demographic variables, core and associated features of each disorder. Characteristics of persons in each group were reviewed. Persons with profound mental retardation were more likely to evince stereotypies or self-injury compared to their severely impaired counterparts. Also, those with stereotypies were more likely to present with Pervasive Developmental Disorder (PDD)/autism, organicity, and eating disorders, while persons with SIB were more likely to evince sleep, sexual, and eating disorders.

Adult↗
PubMedDate not supplied

The relationship of self-injurious behavior and aggression to social skills in persons with severe and profound learning disability.

In this study, we investigated differences in social skills among four groups of individuals with severe and profound learning disabilities. The comparison groups were composed of individuals engaging in self-injurious behavior, aggression, both behaviors, or neither of the behaviors. We measured social skills using the Matson Evaluation of Social Skills for Individuals with Severe Retardation, a standardized assessment of social skills in persons with severe or profound learning disability. The results indicated that individuals displaying maladaptive behaviors exhibited a restricted range of social behaviors compared to controls. Also, group membership based on self-injury and aggression was predicted based on profiles of scores on the Matson Evaluation of Social Skills for Individuals with Severe Retardation. These findings are consistent with reports in other studies that note social skills deficits in aggressive and self-injurious persons with learning disabilities. However, in this case a standardized assessment of these deficits was possible and specific skills problems were identified. Implications of the findings for identification and treatment of self-injury and aggression are discussed.

Adolescent↗
PubMedDate not supplied

Anaplastic sacrococcygeal chordoma. Fine needle aspiration cytologic findings and embryologic considerations.

A case of sacrococcygeal chordoma with anaplastic features is presented. The diagnosis of the anaplastic component was first established by fine needle aspiration (FNA) biopsy, which demonstrated the sarcomatous elements as well as the physaliferous cells characteristic of chordoma. Subsequent histologic examination confirmed these findings. While the FNA cytologic findings of chordoma have been previously reported, this is the first case of an anaplastic chordoma diagnosed by FNA biopsy. The embryologic origin of this unusual tumor and its differential diagnosis are discussed.

Aged↗