Retest stability of DSM-III-R diagnoses among adolescents using the diagnostic interview schedule for children (DISC-2.1C)

Retest stability of DSM-III-R diagnoses was assessed using the DISC-2.1C with a sample of Anglo, African, and Hispanic American adolescent patients 12 to 17 years of age. Based on the kappa statistic, retest stability was fair for any disorder ( =.50), for any anxiety disorder ( =.44), for any affective disorder ( =.53), for any disruptive behavior disorder ( =.58), and for substance use disorders ( =.46). Although there was a trend for reliability to be somewhat higher for African Americans ( =.58) than for Anglos ( =.42) or Hispanics ( =.49), these differences were not statistically significant. In general, 15- to 17-year-olds had somewhat better reliability ( =.58) than did 12- to 14-year-olds ( =.44). Males had somewhat higher reliability ( =.63) than females ( =.43). These findings are congruent with those reported recently using the DISC-R (Schwab-Stone et al., 1993) and suggest that the DISC appears to be at least as reliable as other available child diagnostic instruments. In view of the fair-to-moderate levels of reliability of these instruments in general, future research should focus on the joint effects of instrument, subject, interviewer, and nomenclature on operating characteristics of diagnostic interview schedules, focusing in particular on factors affecting accurate recall and reporting of symptoms and episodes. This research was supported in part by grants MH44214 and MH44773 from the National Institute of Mental Health, and by the Hogg Foundation for Mental Health. The authors wish to acknowledge the participation and collaboration of A. J. Pumariega, J. W. Swanson, and C. E. Holzer III and staff of the Center for Cross-Cultural Research, directed by F. M. Treviño.     

Validation of a full body 3-D dynamic linked segment model

In studies related to human movement, linked segment models (LSM's) are often used to quantify forces and torques, generated in body joints. Some LSM's represent only a few body segments. Others, for instance used in studies on the control of whole body movements, include all body segments. As a consequence of the complexity of 3-dimensional (3-D) analyses, most LSM's are restricted to one plane of motion. However, in asymmetric movements this may result in a loss of relevant information. The aim of the current study was to develop and validate a 3-D LSM including all body segments. Braces with markers, attached to all body segments, were used to record the body movements. The validation of the model was accomplished by comparing the measured with the estimated ground reaction force and by comparing the torques at the lumbo-sacral joint that resulted from a bottom-up and a top-down mechanical analysis. For both comparisons, reasonable to good agreement was found. Sources of error that could not be analysed this way, were subjected to an additional sensitivity analysis. It was concluded that the internal validity of the current model is quite satisfactory.     

Correction of errors in scientific research

Four ways to reduce scientific errors are by tests of equipment and programs, examination of results, peer review, and replication. This article describes various types of errors that may occur and procedures available for the prevention and correction of both unintentional and intentional errors in experiments that use computer programs to generate the stimuli, record the responses, or analyze the data. We describe a case study of a particular experiment that produced a result that has been found to be erroneous. The case study provides additional evidence of the essential importance of replication for the identification and elimination of scientific error.     

Reduction of the elevator illusion from continued hypergravity exposure and visual error-corrective feedback

Ten subjects served as their own controls in two conditions of continuous, centrifugally produced hypergravity (+2 Gz) and a 1-G control condition. Before and after exposure, open-loop measures were obtained of (1) motor control, (2) visual localization, and (3) hand-eye coordination. During exposure in the visual feedback/hypergravity condition, subjects received terminal visual error-corrective feedback from their target pointing, and in the no-visual feedback/hypergravity condition they pointed open loop. As expected, the motor control measures for both experimental conditions revealed very short lived underreaching (the muscle-loading effect) at the outset of hypergravity and an equally transient negative aftereffect on returning to 1 G. The substantial (approximately 17°) initial elevator illusion experienced in both hypergravity conditions declined over the course of the exposure period, whether or not visual feedback was provided. This effect was tentatively attributed to habituation of the otoliths. Visual feedback produced a smaller additional decrement and a postexposure negative aftereffect, possible evidence for visual recalibration. Surprisingly, the target-pointing error made during hypergravity in the no-visual-feedback condition was substantially less than that predicted by subjects’ elevator illusion. This finding calls into question the neural outflow model as a complete explanation of this illusion.     

Neuropsychological evaluation in the assessment of personal injury

Neuropsychological evaluation offers unique potentials in the assessment of personal injury claims. Strengths and limitations of major approaches to testing are reviewed, and special attention is given to applications in the particular forensic areas of head injury, toxic environments, physical disease, and malpractice. The varieties of cognitive, emotional, and interpersonal damages which may occur with brain injury are described. Suggestions are provided for forensically appropriate neuropsychological assessment, as well as guidelines offered for discerning inappropriate practices. Issues of neurological malingering, credentialing of the expert, and forensic roles of the neuropsychologist in rehabilitation are discussed.     

Circadian factors during sustained performance: Background and methodology

Cornell University Medical College, Westchester Division, The New York Hospital, White Plains, New York It is well established that there is a complex timekeeping mechanism in the human brain. This mechanism is associated with a variety of physiological and psychological rhythms having a period of about a day, and thus referred to as circadian rhythms. The circadian system has recently been modeled in terms of two underlying oscillators, one much more resistant to changes in routine than the other. These oscillators are considered to be endogenous, that is, internal to the organism, and not reliant for their existence upon changes in the person’s environment or general behavior. They thus continue to run even when the sleep/wake cycle is suspended, as in sustained operations. Thus, by their very nature, sustained operations require the individual to override the inputs that are coming from his or her circadian system (especially the indication that sleep is required). The aim of this paper is to provide a background to the area of circadian rhythms research, including a section on the methodology, so that the impact of the circadian system on sustained operations can be better understood.