Adaptive force control in grasping as a function of level of developmental disability.

BACKGROUND: The adaptation to the task demands of grasping (grip mode and object mass) was investigated as a function of level of developmental disability. METHODS: Subjects grasped objects of different grip widths and masses that were instrumented to record grip forces. RESULTS: Proportionally, fewer participants from the profound compared with moderate and severe disability groups were able to complete the prehensile tasks. Nevertheless, all participants who completed the task showed adaptive grasping behaviour in terms of level and variability of force produced. There was higher absolute and relative force variability in low mass tasks that was enhanced with greater level of developmental disability. CONCLUSIONS: The findings show task relevant adaptive grasping control with inhibition of force output at very-low-force conditions being the primary performance deficit of the profound disability group as a function of level of developmental disability.

Influences on the ethical beliefs of graduate students concerning research.

Development of and influence on ethical beliefs were surveyed at a major research university campus. Courses were ranked by faculty and students as most important. Mentors were ranked eighth in a list of nine factors. Of the 1,152 returned student questionnaires, 97 (8.4%) made the effort to write comments, and of the 610 faculty questionnaires returned, 64 (10%) wrote comments. These comments were rich in detail and description.

Mentoring and the impact of the research climate.

In this article, we focus on the mentoring process, and we argue that the internal and external pressures extant at research universities may create a research culture that may be antithetical to appropriate mentoring. We developed a scale based on motivation theory to determine the perceived research culture in departments and research laboratories, and a mentoring scale to determine approaches to mentoring graduate students. Participants were 610 faculty members across 49 departments at a research oriented university. The findings were that a mastery-oriented research climate and an outcome-oriented research climate were manifested at the university. More importantly, each research climate had its own unique impact on how the faculty approached mentoring graduate students. A mastery research climate was related to a more supportive approach to mentoring than the outcome research climate. We concluded by suggesting that the outcome research climate may have an adverse effect on effective mentoring and on maintaining research ethics.

The changing effector pattern of tardive dyskinesia during the course of neuroleptic withdrawal.

Tardive dyskinesia (TD) is a movement disorder that can be expressed at various body effector points, including the face, neck, arms, fingers, legs, and torso. In this prospective longitudinal study researchers examined whether the effector pattern of TD changed during the course of neuroleptic medication withdrawal in adults with mental retardation. Results indicated that the effector pattern of TD changed over the course of neuroleptic withdrawal. Peak dyskinesia was associated with the involvement of more body areas relative to baseline. Although dyskinesia decreased at follow-up and fewer body areas showed signs of dyskinesia, there were still differences in the effector pattern of dyskinesia relative to baseline at periods of 1 to 2 years following neuroleptic withdrawal. These findings suggest that TD is a dynamic disorder associated with changes in both severity and effector pattern over time.

Risk factors for tardive dyskinesia in a large population of youths and adults.

This study was designed to identify predisposing factors for tardive dyskinesia (TD) in youths and adults within a large, predominantly developmentally disabled and mentally ill population. The findings support previously reported risk factors for TD, including increasing age, use of anticholinergic medication for those over 40 years old, and long duration of neuroleptic exposure for those over 18 years of age. Higher cumulative levels of "typical" neuroleptic dosage decreased the risk for TD for those over 18. Novel findings included the benefit of personality disorder in individuals 18 to 40 years old and the strong risk factor of profound mental retardation in all age groups. These findings reveal further complex interactions to the risk factors for TD.

Stereotypy and motor control: differences in the postural stability dynamics of persons with stereotyped and dyskinetic movement disorders.

We examined whether dynamic measures of postural stability differentiated persons with stereotyped movement disorder from persons with dyskinetic movement disorder. Participants from three groups (stereotypy, dyskinesia, control) were given a goal-oriented postural stability task, and performance was measured using a force platform and computerized posturographic techniques. The results showed that both movement disorder groups differed from the control group in the posture task. Further, the stereotypy and dyskinesia groups demonstrated markedly different postural movement profiles. The postural motion of the stereotypy group was characterized by greater amplitude and variability but lower complexity than the dyskinesia group. These results provide support for a motor control model of stereotypy.

Dynamics of lip dyskinesia associated with neuroleptic withdrawal.

The lip movements associated with dyskinesia in adults with mental retardation were investigated through a dynamic analysis at medication baseline, at the points of the highest level of withdrawal dyskinesia as indexed by the DISCUS rating scale, and at the lowest level of dyskinesia following complete withdrawal of the medication. Results showed that the changes in the amount of lip oscillations following medication reduction and eventual withdrawal were strongly linked to changes in the structural complexity of the dynamics of lip motions. These findings provide evidence that neuroleptic medication reduces the df of the dynamics of the movement output and that this change is inversely related to the level of tardive dyskinetic motion observed in the clinical setting.

Variability of stereotypic body-rocking in adults with mental retardation.

The variability of stereotypic body-rocking motions of adults with severe and profound mental retardation not on medication was examined through a kinematic analysis. A matched nonretarded group of adults was also examined in the production of preferred rates of body-rocking. The inter- and intra-individual variability of the body-rocking motions was, on average, higher for the individuals with mental retardation, although a few participants showed as low a variability as the least variable participants in the nonretarded group. These findings provide further evidence that the kinematic variability of stereotypies is not lower than that displayed by others engaged in similar movement activities and support the proposition that low variability of discrete kinematic variables may not be a defining feature of stereotypy.

Dynamics of self-injurious behaviors.

Self-injurious behavior was examined in a case study of head-banging by an 8-year-old girl with profound mental retardation and an autistic disorder. Trajectories of the arm movements and impact forces of the head blows were determined from a dynamic analysis of videotapes. Results revealed a high degree of cycle-to-cycle consistency in the qualitative dynamics of the limb motions, with one hand motions being faster than those with two hands (inphase and antiphase) and the motions with the helmet about 25% faster than those without the helmet. The impact force of SIBs as a percentage of body weights are near the low end of forces generated in boxing blows and karate hits.

Akathisia in adults with mental retardation: development of the Akathisia Ratings of Movement Scale (ARMS).

We developed an akathisia rating scale for use with persons who have mental retardation and screened for the occurrence of akathisia in three samples: 66 adults receiving maintenance neuroleptic treatment, 20 adults not receiving neuroleptics, and 8 adults undergoing neuroleptic dose reduction. The scale had an acceptable level of interrater reliability and validly measured group differences related to neuroleptic treatment status. Using an empirically derived cut-off-score, we estimated the prevalence rate for akathisia to be 5% in neuroleptic-free subjects, 17% in neuroleptic-maintenance subjects, and 25% in neuroleptic-reduction subjects. Akathisia, dyskinesia, and stereotypy manifested as qualitatively different movement topograhies. The occurrence of dyskinesia stereotyped movement disorder was associated significantly with an increased occurrence of akathisia.

Dyskinetic movement disorder among adults with mental retardation: phenomenology and co-occurrence with stereotypy.

We screened for the occurrence of dyskinetic and stereotypic movement disorders using item-independent screening protocols to determine whether these forms of movement disorder can be distinguished among adults with mental retardation. Stereotypies and dyskinesias were reliably distinguished in terms of topography. Tardive dyskinesia occurred in 18.2% of a cohort of individuals receiving chronic neuroleptic treatment. Stereotypic movement disorder was associated with increased dyskinesia scores and increased prevalence of tardive dyskinesia. Increased dyskinesia scores were also found for subjects exhibiting stereotypy who had been free of neuroleptic treatment for 3 years. Results indicate that dyskinesia and stereotypy are discriminable movement disorders and provide preliminary support for the hypothesis that they may be related by common mechanisms.

Facial stereotypic movements and tardive dyskinesia in a mentally retarded population.

The facial stereotypies of adults diagnosed as having mental retardation and tardive dyskinesia were examined through a kinematic analysis of video-taped lip and tongue motions. A control group of healthy adult subjects without mental retardation was also examined in the production of preferred rates of lip and tongue oscillatory motions to provide a basis to assess the degree of movement variability in the stereotypies. The inter- and intraindividual variability of the movement form characteristics of the lip and tongue stereotypic motions was higher in the subjects with mental retardation. Results suggest that the low variability of discrete properties of movement kinematics may not be a defining feature of stereotypies. The concept of invariance in stereotypies may relate only to the topological kinematic properties of the movement sequence that provide the basis to infer that the same stereotypic movement sequence was reproduced from observation to observation.

The dynamical structure of tremor in tardive dyskinesia.

The movement disorder syndrome of tardive dyskinesia arises as a consequence of prolonged regimens of neuroleptic medication, and is characterized, although not exclusively, by jerky and sometimes rhythmical stereotypical motions in a wide range of muscle systems. It is well established that the degree and variability of tremor in tardive dyskinesia is greater than that in normal age-matched subjects. The findings from the current experiment show that the dimension of the tardive dyskinetic finger tremor time series is systematically lower than that evident in normal finger tremor. Furthermore, the variability of finger motion in both groups is inversely related to the dimension of the respective attractor dynamic. The neuroleptic medication appears to constrain the degrees of freedom regulated in organization of the motor system. (c) 1995 American Institute of Physics.

How well do physicians, pharmacists, and psychologists assess tardive dyskinesia movements?

OBJECTIVE: To measure and compare the tardive dyskinesia assessment ability of physicians, pharmacists, and psychologists prior to and after formal training. METHOD: One hundred twenty-two physicians, 82 pharmacists, and 78 psychologists participated in assessment training with the Dyskinesia Identification System Condensed User Scale (DISCUS). Participants were shown one of three videotapes as a pretest before training and as a posttest after training. Inter- and intraprofessional comparisons were made on total score, body area scores, and individual item scores. Multivariate analysis of variance (MANOVA) was used. If significant differences were found, analysis of variance (ANOVA) was conducted. To identify where significant effects occurred, the Tukey test was used. RESULTS: The group as a whole improved from a pretest total point difference from criteria of 6.3 +/- 5.7 SD to a posttest difference of 2.8 +/- 2.8 SD (df = 2, f = 84.32, p < 0.001). This training effect occurred for six of the seven videotape testing sequences used. Physicians, pharmacists, and psychologists did not significantly differ from each other before or after training. All three professions significantly improved as a result of training. A subgroup of 39 psychiatrists within the physician group showed similar results. CONCLUSIONS: Untrained raters, regardless of profession, are not necessarily accurate in quantifying dyskinetic movements. Brief but formal training significantly improves accuracy.

Quantification of postural sway patterns in tardive dyskinesia.

An assessment was made of the orientation and variability in postural center of pressure patterns in individuals with tardive dyskinesia (TD) and/or developmental disability during quiet standing. Postural patterns were compared and contrasted between four groups of individuals: those with (a) TD and developmentally disabled (severely and profoundly retarded); (b) developmental disability only; (c) TD but of normal intelligence; and (d) a healthy control group. The center of pressure displacements were derived from the lateral, vertical, and anterior-posterior force and moment components of force platform measurements. Analyses demonstrated that individuals with TD in combination with developmental disability had a different center of pressure orientation and variability compared to healthy individuals and individuals suffering only from developmental disability or TD. The center of pressure pattern in the developmentally disabled TD group was characterized by a more prominent lateral orientation, whereas in the other three groups, it had a more predominant anterior-posterior orientation. In addition, the variability in these orientation components was much smaller in the developmentally disabled TD group, indicating a more regular pattern of sway in the center of pressure during quiet standing in these individuals. These findings show that assessments of postural center of pressure profile orientation and variability may be useful indicators for investigating TD, especially in distinguishing between developmental disability and TD.

Arm tremor, tardive dyskinesia, and mental retardation.

The arm tremor of adults diagnosed as having mental retardation and/or tardive dyskinesia was examined through an analysis of the acceleration properties of several arm postures. The degree of arm acceleration was increased in all groups compared to a control group without mental retardation. The tardive dyskinesia and/or mentally retarded groups also showed a shift to a lower modal frequency of physiological tremor. Results showed that both time domain and frequency properties of the tremor acceleration signal are necessary to distinguish between groups. The neuroleptic medication appears to engender a dual and opposing influence on performance in the arm tremor task for the mentally retarded group. The medication reduces behavioral variability as indexed by analyses of arm acceleration over time (time domain) but lowers the modal frequency of physiological tremor.

The dyskinesia Identification System Condensed User Scale (DISCUS): reliability, validity, and a total score cut-off for mentally ill and mentally retarded populations.

Items means and standard deviations, reliability, and validity for the Dyskinesia Identification System Condensed User Scale (DISCUS) are presented for mentally ill and mentally retarded populations. A total score cut-off was developed and tested against physician diagnosis and the Research Diagnoses for Tardive Dyskinesia (RD-TD; Schooler & Kane, 1982). DISCUS total score reliability was .92 for mentally ill and .91 for mentally retarded individuals. The DISCUS total score was significantly greater for 108 diagnosed tardive dyskinesia (TD) cases compared to 108 matched controls. The DISCUS total score of 5 or above was associated significantly with physician TD diagnosis and the RD-TD intensity criterion. The psychometrically derived DISCUS cut-off score of 5 or above is a "red flag" that clinicians may use in monitoring individuals prescribed antipsychotic medication for TD.

Correlations between kinematic and rating scale measures of tardive dyskinesia in a developmentally disabled population.

This paper reports a study that examines the relations between Dyskinesia Identification System: Condensed User Scale (DISCUS) scores and a battery of postural and movement kinematic measures in a group of adults diagnosed as being developmentally disabled and screened as having tardive dyskinesia. The results showed that finger tremor measures correlated with the tongue tremor and pill rolling items of DISCUS, whereas the postural stability scores correlated with the toe movement item of DISCUS and the total DISCUS score. There was also a high stability in subject kinematic performance from trial to trial over the postural and movement tests. The pattern of correlations between the DISCUS items and movement kinematic measures is consistent with the proposition that tremor is a centrally rather than peripherally driven phenomenon, although many factors contribute to emergent tremors. These findings provide construct and content validity for the DISCUS as a screening device for tardive dyskinesia and suggest that certain posture and movement kinematic measures could be sensitive measuring methods for tardive dyskinesia in developmentally disabled populations.