Remediation of perceptual organisation in schizophrenia.

Introduction Impaired perceptual organisation in schizophrenia has been repeatedly described in clinical and research literatures. It has also been associated with problems in more complex aspects of visual function, including visuospatial and visual cognitive test performance. Two therapeutic interventions were developed here that target perceptual organisation: (1) Computer-based training, which emphasized stimulus-driven processing (bottom-up approach), and (2) Instrumental Enrichment therapy, which is a therapist-guided interactive learning method (top-down approach). Methods Twenty-eight patients diagnosed with schizophrenia or schizoaffective disorder participated in a 12-week programme. For both forms of interventions, task difficulty increased progressively, based upon successful performance. The third group of patients, which served as controls, received a similar therapeutic intervention that did not include a perceptual organisation component. Before and after intervention, participants received tests of perceptual organisation, as well as a battery of neuropsychological tests. Results Results indicate that both forms of intervention improved perceptual organisation ability relative to the control condition. In addition, the improvement was found for select neuropsychological tests, although the pattern of improvement did not favour capacities more closely associated with visual organisational or visuospatial function. Conclusions Together, results demonstrate the effectiveness of new remediation protocols that target mid-level visual processing, which generalized to select visual cognitive functions.

Visual training improves perceptual grouping based on basic stimulus features.

Training on visual tasks improves performance on basic and higher order visual capacities. Such improvement has been linked to changes in connectivity among mediating neurons. We investigated whether training effects occur for perceptual grouping. It was hypothesized that repeated engagement of integration mechanisms would enhance grouping processes. Thirty-six participants underwent 15 sessions of training on a visual discrimination task that required perceptual grouping. Participants viewed 20 × 20 arrays of dots or Gabor patches and indicated whether the array appeared grouped as vertical or horizontal lines. Across trials stimuli became progressively disorganized, contingent upon successful discrimination. Four visual dimensions were examined, in which grouping was based on similarity in luminance, color, orientation, and motion. Psychophysical thresholds of grouping were assessed before and after training. Results indicate that performance in all four dimensions improved with training. Training on a control condition, which paralleled the discrimination task but without a grouping component, produced no improvement. In addition, training on only the luminance and orientation dimensions improved performance for those conditions as well as for grouping by color, on which training had not occurred. However, improvement from partial training did not generalize to motion. Results demonstrate that a training protocol emphasizing stimulus integration enhanced perceptual grouping. Results suggest that neural mechanisms mediating grouping by common luminance and/or orientation contribute to those mediating grouping by color but do not share resources for grouping by common motion. Results are consistent with theories of perceptual learning emphasizing plasticity in early visual processing regions.

Relationship Between Peer Victimization and Posttraumatic Stress Among Primary School Children.

Peer victimization is a common stressor experienced by children. Although peer victimization has been studied extensively, few studies have examined the potential link between peer victimization and posttraumatic stress disorder (PTSD), and no studies of which we are aware have examined this link among children in primary school. The paucity of studies examining the link between PTSD and peer victimization in primary school is surprising because peer victimization occurs more frequently and is more likely to be physical among 7- and 8-year-old children. This study assessed the relationship between peer victimization and PTSD in a sample of 358 elementary school children (ages 6-11 years). Results indicated that peer victimization accounted for 14.1% of PTSD symptom severity among boys and 10.1% among girls. Additionally, we found gender differences in the types of peer victimization that were most associated with PTSD symptom severity (d = 0.38). The long-term developmental consequences that may be associated with peer victimization-linked PTSD symptomatology are discussed.

Speed of perceptual grouping in acquired brain injury.

Evidence exists that damage to white matter connections may contribute to reduced speed of information processing in traumatic brain injury and stroke. Damage to such axonal projections suggests a particular vulnerability to functions requiring integration across cortical sites. To test this prediction, measurements were made of perceptual grouping, which requires integration of stimulus components. A group of traumatic brain injury and cerebral vascular accident patients and a group of age-matched healthy control subjects viewed arrays of dots and indicated the pattern into which stimuli were perceptually grouped. Psychophysical measurements were made of perceptual grouping as well as processing speed. The patient group showed elevated grouping thresholds as well as extended processing time. In addition, most patients showed progressive slowing of processing speed across levels of difficulty, suggesting reduced resources to accommodate increased demands on grouping. These results support the prediction that brain injury results in a particular vulnerability to functions requiring integration of information across the cortex, which may result from dysfunction of long-range axonal connection.

Spatial-temporal characteristics of perceptual organization following acquired brain injury.

OBJECTIVE: To assess characteristics of perceptual organization following brain injury. RESEARCH DESIGN: A repeated measures between groups design. METHODS: Perceptual thresholds were compared between 10 persons with brain injury and 10 demographically matched healthy control subjects. Ten young control subjects were also tested to evaluate effects of normal ageing on these processes. Participants viewed stimuli on a computer monitor in which regularities existed in either the spatial or temporal domain. Psychophysical measurements were made of perceptual thresholds, as well as time required to process stimuli. RESULTS: Relative to age-matched control subjects, patients were impaired on all measures, with greatest deficits in conditions that contained a temporal component. Impairment did not occur with normal ageing. CONCLUSIONS: These results reflect cognitive impairment resulting from reduced cortical integrative function as well as reduced information processing speed. Such deficits at this level of processing likely impact subsequent perceptual function, such as object recognition.

Effect of a social work liaison program on family caregivers to people with brain injury.

OBJECTIVE: We assessed the effect of a social work liaison program on caregiver outcomes for families caring for people with brain injury. DESIGN: All telephone calls received by the team were entered into a standardized log form to record topics raised by caregivers. MAIN OUTCOME MEASURES: We compared the experience of this cohort of traumatic brain injury (TBI) caregivers with the experience of an earlier cohort by use of standard measures of caregiver mental health. Because patients in the cohort had mixed etiologies, we also examined the experience of caregivers according to type of brain injury, comparing cerebrovascular accident with TBI patients. RESULTS: The social work liaison program offered benefit to caregivers on burden, satisfaction, and mastery outcomes. CONCLUSIONS: This research suggests that a relatively low-cost, nonintensive intervention may offer substantial benefit to families caring for people with brain injury.