Selective attention in cerebral palsied and normal children

Noninstitutionalized, educable retarded, spastic cerebral palsied children of two mental age (MA) levels were compared with normal MA controls on a task measuring selective attention and were not found deficient in selective attention. For both the cerebral palsied and the normals there was an increase in selective attention efficiency with an increase in MA. The results support the position that MA rather than chronological age or IQ is the important variable in determining selective attention performance. The results do not support the attention-deficit theory; they do support the argument that institutionalization has a negative affect on attention. The effects of brain damage and retardation on selective attention ability were discussed.Thanks are expressed to Eleanor Rennie, Head Teacher, Robert Massie, Supervisor of Special Education, and E. F. DeFord, Assistant Director, Department of Research for the Richmond Public Schools, Richmond, Virginia. Appreciation is also given to Scott Hamrick, Principal, Jackson Via Elementary School, Charlottesville, Virginia. Susan Autrey is also thanked for assistance in data collection.     

Research on effects of color reversal on the visual perceptual and visuomotor performances of spastic cerebral palsied and other exceptional individuals

Research pertaining to the effects of color-reversal (black and white) on the visual perceptual and visuomotor performances of spastic cerebral-palsied children and other exceptional individuals was examined. In general, evidence to date suggests that spastic cerebral-palsied children show significant improvement in visuomotor and visual perceptual performance with the color-reversal of the standard black-on-white figure-ground relationship in stimulus and response materials of standardized tests.     

Automated reinforcement of head posture in two cerebral palsied retarded children.

A transistor radio activated by a mercury switch was used to reinforce head posture in two retarded children with severe cerebral palsy. Under the contingent music condition dropping the head forward automatically terminated the broadcast (music). A comparison of baseline and treatment phases showed that head orientation was strongly controlled by contingent music.     

Perturbation of a skilled action 1. The responses of neurologically normal and cerebral palsied individuals

Subjects were trained to execute rhythmical forward and backward arm swings, with consistent timing and displacement characteristics. A DC servomotor was used to introduce brief perturbations, opposing elbow extension. Pilot studies indicated that: (1) Weak disturbances tended to foreshorten the voluntary action, while larger perturbations (strong enough to reverse the ongoing action) caused positional overshooting. (2) When prolonged ( > 500 msec) perturbations were investigated, there was no evidence that EMG responses within the first 100 msec provided much force to counter the disturbance. (3) Subjects were unable to learn to curb the steep rises in velocity observed when strong perturbations were released, despite extensive feedback experience. The main study confirmed that electromyographic and movement parameters reflect the magnitude of the perturbation. The actions of cerebral palsied subjects were more disrupted by perturbations, abnormal antagonist activity and clonus were recorded. Models of compensation are discussed.     

Effects of increased complexity of visuo-motor transformations on children's arm movements

The effects of increasing complexity of visuo-motor transformations on movement were examined in 4-, 6-, and 8-year-old children and adults. Participants performed a 'center-out' drawing task under three increasingly complex conditions: (1) Normal transformation: The target, line path and hand position were fully visible, in the horizontal plane, throughout the movement. (2) Aligned transformation: The target and line path were displayed horizontally above the workspace, with vision of the arm/hand occluded. (3) Vertical transformation: The target and line paths were presented on a vertical computer monitor with vision of the arm/hand occluded. Results showed that with increasing age, movements became faster, straighter, and smoother. The 4- and 6-year-old children were more variable in their specification of movement direction than the 8-year-old children and the adults, and were also more affected by the complexity of the transformation. This suggested that besides the complexity of the visual transformation, the familiarity/experienced environment might also play a role in 'sharpening' the transformation maps represented in movement planning.     

Perturbation of a skilled action 2. normalising the responses of cerebral palsied individuals

Subjects were trained to execute a radial elbow extension of prescribed arc and velocity profile. A DC servomotor was used to introduced brief perturbations, opposing extension. Neurologically normal and cerebral palsied subjects' reactions to a range of perturbation magnitudes were tested. The training stage of the study was designed to provide cerebral palsied subects with an electromyographic target profile of how to respond to a given perturbation,modelled on the performances of neurologically normal subjects, but taking account of individual differences in how non-perturbed arm swings were executed electromyographically. In the event, spastic subjects were not hyperreactive to perturbations when tested. A follow-up study confirmed the interpretation that this was a consequence of learning to perform the test arm swing with stringent precision. The implications of the study for models of spasticity and prospects for rehabilitation are discussed.     

Effects of amphetamine on vigilance performance in normal and hyperactive children

Deficient sustained attention is a symptom of hyperactivity that can be improved by stimulant medication. Recently, amphetamine has been shown to increase detections during a vigilance task in both normal and hyperactive boys. The present study applied signal detection analysis to the vigilance performance of 15 hyperactive and 14 normal boys divided into two age groups (6–9 and 10–12). A computerized continuous performance test was administered under amphetamine and placebo. Overall group comparisons indicated that perceptual sensitivity or d was higher for the normal boys and the older groups, and analysis of drug treatments showed that amphetamine significantly increased d. Interactions between drugs and age groups demonstrated that amphetamine affected the younger boys to a significantly greater degree than the older children for both d and response bias or . It is notable that the results were essentially parallel for both normal and hyperactive children.     

Comments on Hughes and Sussman''s time-sharing study of cerebral laterality in language-disordered and normal children

M. Hughes and H. M. Sussman (1983, Brain and Language, 19, 48-64) suggest that the time-sharing paradigm "does not serve as an adequate behavioral index for language lateralization in children." The merits of this conclusion are considered and general interpretative issues regarding manual interference in dual-task/time-sharing studies are discussed.     

A follow-up study of young cerebral palsied patients Some psychological, educational and vocational aspects

Abstract.— In a follow-up study of 39 non-oligophrenic spastic adolescents and young adults it was found that 85% attended normal schools, the rest went to schools for physically or mentally handicapped. If retarded children with learning difficulties were left out of account, there were no more than 10% regular problem cases, an incidence which is very close to what is found among ordinary, non-handicapped Danish school children.-With regard to vocational career, nearly 80% were estimated to be able to obtain and remain in open employment. About one third had experienced rather pronounced vocational problems either because of physical weakness and slowness, or because of personality disturbances or intellectual retardation. Females appeared generally more content with and successful in their jobs than the males. There was an overrepresentation of clients with a mild physical handicap in the problem group, indicating that it may be difficult to occupy such a "marginal" position with its easy accs to comparison and competition with the socalled normal standards.-A close relationship was found between the data from the original psychological evaluation and the course of schooling. In contrast, there was a low agreement between the childhood reports and the follow-up employment data.