Slow binocular rivalry in bipolar disorder

Background. The rate of binocular rivalry has been reported to be slower in subjects with bipolar disorder than in controls when tested with drifting, vertical and horizontal gratings of high spatial frequency. Method. Here we assess the rate of binocular rivalry with stationary, vertical and horizontal gratings of low spatial frequency in 30 subjects with bipolar disorder, 30 age- and sex-matched controls, 18 subjects with schizophrenia and 18 subjects with major depression. Along with rivalry rate, the predominance of each of the rivaling images was assessed, as was the distribution of normalized rivalry intervals. Results. The bipolar group demonstrated significantly slower rivalry than the control, schizophrenia and major depression groups. The schizophrenia and major depression groups did not differ significantly from the control group. Predominance values did not differ according to diagnosis and the distribution of normalized rivalry intervals was well described by a gamma function in all groups. Conclusions. The results provide further evidence that binocular rivalry is slow in bipolar disorder and demonstrate that rivalry predominance and the distribution of normalized rivalry intervals are not abnormal in bipolar disorder. It is also shown by comparison with previous work, that high strength stimuli more effectively distinguish bipolar from control subjects than low strength stimuli. The data on schizophrenia and major depression suggest the need for large-scale specificity trials. Further study is also required to assess genetic and pathophysiological factors as well as the potential effects of state, medication, and clinical and biological subtypes.

Widespread sensory hypersensitivity is a feature of chronic whiplash-associated disorder but not chronic idiopathic neck pain

Objectives: To investigate sensory changes present in patients with chronic whiplash-associated disorders and chronic idiopathic neck pain using a variety of quantitative sensory tests to better understand the pain processing mechanisms underlying persistent symptoms. Methods: A case control study was used with 29 subjects with chronic whiplash-associated disorders, 20 subjects with chronic idiopathic neck pain, and 20 pain-free volunteers. Pressure pain thresholds were measured over the articular pillars of C2-C3, C5-C6, the median, radial, and ulnar nerve trunks in the arm and over a remote site, the muscle belly of tibialis anterior. Heat pain thresholds, cold pain thresholds, and von Frey hair sensibility were measured over the cervical spine, tibialis anterior, and deltoid insertion. Anxiety was measured with the Short-Form of the Spielberger State Anxiety Inventory. Results: Pressure pain thresholds were decreased over cervical spine sites in both subject groups when compared with controls (P < 0.05). In the chronic whiplash-associated disorders group, pressure pain thresholds were also decreased over the tibialis anterior, median, and radial nerve trunks (P < 0.001). Heat pain thresholds were decreased and cold pain thresholds increased at all sites (P < 0.03). No differences in heat pain thresholds or cold pain thresholds were evident in the idiopathic neck pain group at any site compared with the control group (P > 0.27). No abnormalities in von Frey hair sensibility were evident in either neck pain group (P > 0.28). Discussion: Both chronic whiplash-associated disorders and idiopathic neck pain groups were characterized by mechanical hyperalgesia over the cervical spine. Whiplash subjects showed additional widespread hypersensitivity to mechanical pressure and thermal stimuli, which was independent of state anxiety and may represent changes in central pain processing mechanisms. This may have implications for future treatment approaches.

Posttraumatic stress disorder and general psychopathology in children and adolescents following a wildfire disaster

Objective: To report on the use of the Post Traumatic Stress Disorder Reaction Index (PTSD-RI) and the Strengths and Difficulties Questionnaire (SDQ) in identifying children and adolescents who may require psychological interventions following exposure to a wildfire disaster. Method: Six months after a wildfire disaster, we conducted a school-based program to screen for wildfire-related events, such as exposure to and perception of threat, posttraumatic stress disorder (PTSD), and general psychopathology. Results: The screening battery was completed by 222 children (mean age 12.5 years, SD 2.48; range 8 to 18 years). Severe or very severe PTSD was reported by 9.0% of students, while 22.6% scored in the abnormal range on the Emotional Symptoms subscale of the SDQ. Younger children and individuals with greater exposure to and perception of threat experienced higher levels of PTSD and general psychopathology. Female students reported a greater perception of threat but did not report higher levels of PTSD or other symptoms. Conclusions: Screening was well received by students, parents, and staff and proved feasible in the postdisaster environment. The PTSD-RI and SDQ demonstrated different individual risk associations and functioned as complementary measures within the screening battery. The identification of children at greatest risk of mental health morbidity enabled service providers to selectively target limited mental health resources.

Secondary school support teachers' perception of speech-language pathology services to adolescents

A survey was conducted to investigate secondary school support teachers' perceptions of speech-language pathology services to students experiencing language difficulties. Information was sought regarding support teachers' understanding of language disorder, their experience with students who have language difficulties and their involvement with speech-language pathologists with regard to these students. Support teachers' views on supporting adolescents who are experiencing language difficulties were also sought as well as information regarding their satisfaction with speech-language pathology services to adolescents. Findings indicated variations in support teachers' perceptions, including mixed views regarding how speech-language pathologists should offer assistance to students. The need for support teachers and speech-language pathologists to offer each other professional training was indicated.

The functional impact of developmental co-ordination disorder during adolescence and early adult life

PURPOSE: The purpose of this study was to increase the understanding of the functional impact that coordination problems have during adolescence and early adult life. In particular, this study aimed to investigate the impact coordination deficits have on day-to-day functioning, activity levels, self-concept with respect to coordination, leisure pursuits, occupational types, accidents and injuries, as well as experiences learning to drive. RELEVANCE: This study may enable clinicians to identify at risk situations, such that appropriate prevention and targeting of treatment can occur. SUBJECTS: The participants involved in this study comprised two groups; 40 subjects previously diagnosed with DCD, and their matched controls. METHODS: Participants were initially contacted by mail for their consent to the study. Consenting participants were then contacted via telephone, and interviewed. ANALYSES: Data analysis was performed using SPSS. Chi squared analysis and Mann Whitney U test was also used to compare groups. RESULTS: During both age periods, the number of DCD subjects participating in sport was significantly less than the number of controls. Although in the 12-14 years age category, the two groups displayed similar results for the type of sport chosen, the 18 – 20 years age group, showed significant differences, with the number of DCD subjects participating in High level coordination activities, being significantly less than controls. Self-perception with respect to coordination was also significantly different amongst groups with more DCD subjects, having perceived themselves as being clumsy. Similarly, a significantly greater number of DCD subjects admitted to tripping over themselves regularly. Some differences have also been noted in the experiences of subjects learning to drive. First, the number of DCD subjects, who had difficulties learning to drive was significantly greater than controls. Second, a much greater number of Control subjects, compared to DCD subjects were successful in obtaining drivers license. Finally, also of interest is the 58% of DCD subjects who have experienced an accident whilst driving, compared to the 35% of controls. The last result of this study was that whilst there was no significant difference between groups, in the number of broken bones, dislocated joints, sprain, burns, stitches, or other significant injuries, the number of control subjects suffering muscle strains was significantly greater than the number of DCD subjects. CONCLUSION: The results of this study indicate that DCD has many implications on day-to-day functioning, both in adolescence and early adulthood. Findings have shown despite the significant sensory-motor deficits displayed by DCD subjects, the impact that this has on day-to-day functioning may be reduced by lifestyle modification.

Expertise and the perception of kinematic and situational probability information

Two experiments were conducted on the nature of expert perception in the sport of squash. In the first experiment, ten expert and fifteen novice players attempted to predict the direction and force of squash strokes from either a film display (occluded at variable time periods before and after the opposing player had struck the ball) or a matched point-light display (containing only the basic kinematic features of the opponent's movement pattern). Experts outperformed the novices under both display conditions, and the same basic time windows that characterised expert and novice pick-up of information in the film task also persisted in the point-light task. This suggests that the experts' perceptual advantage is directly related to their superior pick-up of essential kinematic information. In the second experiment, the vision of six expert and six less skilled players was occluded by remotely triggered liquid-crystal spectacles at quasi-random intervals during simulated match play. Players were required to complete their current stroke even when the display was occluded and their prediction performance was assessed with respect to whether they moved to the correct half of the court to match the direction and depth of the opponent's stroke. Consistent with experiment 1, experts were found to be superior in their advance pick-up of both directional and depth information when the display was occluded during the opponent's hitting action. However, experts also remained better than chance, and clearly superior to less skilled players, in their prediction performance under conditions where occlusion occurred before any significant pre-contact preparatory movement by the opposing player was visible. This additional source of expert superiority is attributable to their superior attunement to the information contained in the situational probabilities and sequential dependences within their opponent's pattern of play.

Hitting a moving target: Perception and action in the timing of rapid interceptions

Different interceptive tasks and modes of interception (hitting or capturing) do not necessarily involve similar control processes. Control based on preprogramming of movement parameters is possible for actions with brief movement times but is now widely rejected; continuous perceptuomotor control models are preferred for all types of interception. The rejection of preprogrammed control and acceptance of continuous control is evaluated for the timing of rapidly executed, manual hitting actions. It is shown that a preprogrammed control model is capable of providing a convincing account of observed behavior patterns that avoids many of the arguments that have been raised against it. Prominent continuous perceptual control models are analyzed within a common framework and are shown to be interpretable as feedback control strategies. Although these models can explain observations of on-line adjustments to movement, they offer only post hoc explanations for observed behavior patterns in hitting tasks and are not directly supported by data. It is proposed that rapid manual hitting tasks make up a class of interceptions for which a preprogrammed strategy is adopted-a strategy that minimizes the role of visual feedback. Such a strategy is effective when the task demands a high degree of temporal accuracy.

Studies of Cognition and Emotion in Organisations: Attribution, Affective Events, Emotional Intelligence and Perception of Emotion

This article details the author’s attempts to improve understanding of organisational behaviour through investigation of the cognitive and affective processes that underlie attitudes and behaviour. To this end, the paper describes the author’s earlier work on the attribution theory of leadership and, more recently, in three areas of emotion research: affective events theory, emotional intelligence, and the effect of supervisors’ facial expression on employees’ perceptions of leader-member exchange quality. The paper summarises the author’s research on these topics, shows how they have contributed to furthering our understanding of organisational behaviour, suggests where research in these areas are going, and draws some conclusions for management practice.

The role of affect, fairness, and social perception in team member exchange

Accumulating evidence suggests that Team-member exchange (TMX) influences employee work attitudes and behaviours separately from the effects of leader-member exchange (LMX). In particular, little is known of the effect of LMX differentiation (in-group versus out-group) as a process of social exhange that can, in turn, affect TMX quality. To explore this phenomenon, this chapter presents a multi-level model of TMX in organizations, which incorporates LMX differentiation, team identification, team member affect at the individual level, and fairness of LMX differentiation and affective climate at the group-level. We conclude with a discussion of the implications of our model for theory, research, and practice.

Serious criminal offending and mental disorder - Case linkage study

Background A relationship exists between mental disorder and offending behaviours but the nature and extent of the association remains in doubt. Method Those convicted in the higher courts of Victoria between 1993 and 1995 had their pyschiatric history explored by case linkage to a register listing virtually all contacts with the public psychiatric services. Results Prior psychiatric contact was found in 25% or offenders, but the personality disorder and substance misuse accounted for much of this relationship. Schizophrenia and affective disorders were also over-represented, particularly those with coexisting substance misuse. Conclusions The increased offending in schizophrenia and affective illness is modest and may often be mediated by coexisting substance misuse. The risk of a serious crime being committed by someone with a major mental illness is small and does not justify subjecting them, as a group, to either increased institutional containment or greater coercion.

The influence of joint position on the dynamics of perception-action coupling

Six right-handed subjects performed rhythmic flexion and extension movements of the index finger in time with an auditory metronome. On each block of trials, the wrist of the response hand was placed in a extended, neutral or flexed position. In the flex-on-the-beat condition, subjects were instructed to coordinate maximum excursion in the direction of finger flexion with each beat of the metronome. In the extend-on-the-beat condition, subjects were instructed to coordinate maximum excursion in the direction of finger extension with each beat of the metronome. The frequency of the metronome was increased from 2.00 Hz to 3.75 Hz in 8 steps (8 s epochs) of 0.25 Hz. During trials prepared in the extend-on-the-beat pattern, all subjects exhibited transitions to either a flex-on-the-beat pattern or to phase wandering as the frequency of pacing was increased. The time at which these transitions occurred was reliably influenced by the position of the wrist. Four subjects exhibited qualitative departures from the flex-on-the-beat pattern at pacing frequencies that were greater than those at which the extend-on-the-beat pattern could be maintained. The lime at which these departures occurred was not influenced by the position of the wrist. These results are discussed with reference to the constraints imposed on the coordination dynamics by the intrinsic properties of the neuromuscular-skeletal system.

The Australian public's perception of genetically-engineered foods

This paper describes a recent Australian survey on attitudes to genetically-engineered foods. Initial results of the survey are discussed and presented in tabular form. While there is some acceptance of particular genetically-engineered products, the results show that responfdents did have concerns over the long-term health effects of eating genetically-engineered foods and the potential risk to the environment. Respondents clearly endorsed labelling of the products and government control of the technology.

Dysregulated hematopoiesis and a progressive neurological disorder induced by expression of an activated form of the human common beta chain in transgenic mice

Previously we described activating mutations of h beta(c), the common signaling subunit of the receptors for the hematopoietic and inflammatory cytokines, GM-CSF, IL-3, and IL-5. The activated mutant, h beta(c)FI Delta, is able to confer growth factor-independent proliferation on the murine myeloid cell line FDC-P1, and on primary committed myeloid progenitors. We have used this activating mutation to study the effects of chronic cytokine receptor stimulation. Transgenic mice were produced carrying the h beta(c)FI Delta cDNA linked to the constitutive promoter derived from the phosphoglycerate kinase gene, PGK-1. Transgene expression was demonstrated in several tissues and functional activity of the mutant receptor was confirmed in hematopoietic tissues by the presence of granulocyte macrophage and macrophage colony-forming cells (CFU-GM and CFU-M) in the absence of added cytokines. All transgenic mice display a myeloproliferative disorder characterized by splenomegaly, erythrocytosis, and granulocytic and megakaryocytic hyperplasia. This disorder resembles the human disease polycythemia vera, suggesting that activating mutations in h beta(c) may play a role in the pathogenesis of this myeloproliferative disorder. In addition, these transgenic mice develop a sporadic, progressive neurological disease and display bilateral, symmetrical foci of necrosis in the white matter of brain stem associated with an accumulation of macrophages. Thus, chronic h beta(c) activation has the potential to contribute to pathological events in the central nervous system.

Effect of disorder on quantum phase transitions in anisotropic XY spin chains in a transverse field

We present some exact results for the effect of disorder on the critical properties of an anisotropic XY spin chain in a transverse held. The continuum limit of the corresponding fermion model is taken and in various cases results in a Dirac equation with a random mass. Exact analytic techniques can then be used to evaluate the density of states and the localization length. In the presence of disorder the ferromagnetic-paramagnetic or Ising transition of the model is in the same universality class as the random transverse field Ising model solved by Fisher using a real-space renormalization-group decimation technique (RSRGDT). If there is only randomness in the anisotropy of the magnetic exchange then the anisotropy transition (from a ferromagnet in the x direction to a ferromagnet in the y direction) is also in this universality class. However, if there is randomness in the isotropic part of the exchange or in the transverse held then in a nonzero transverse field the anisotropy transition is destroyed by the disorder. We show that in the Griffiths' phase near the Ising transition that the ground-state energy has an essential singularity. The results obtained for the dynamical critical exponent, typical correlation length, and for the temperature dependence of the specific heat near the Ising transition agree with the results of the RSRODT and numerical work. [S0163-1829(99)07125-8].