Biomedical subjects

G M Pace

Publications and source records attributed to G M Pace.

At least 19 recordsLinked to original sources

PubMed2005

Antecedent interventions in the management of maladaptive behaviours in a child with brain injury.

Typically behaviour management plans attempt to change behaviour by manipulating the environmental consequences of selected behaviour. However, identifying the antecedent events that precede behaviour has also been demonstrated to be an important component of effective behaviour change programmes. The present case presentation attempts to demonstrate how antecedent procedures could be used to effectively manage behaviour problems in individuals with brain injury. Visual inspection of changes in the frequency of physical aggression and self-injurious behaviour of a child with brain injury provides preliminary data supporting the use of an intervention package of antecedent and consequence-based procedures. Clinical implications, limitations and possibilities for future research of antecedent control procedures are discussed.

Aggression↗

PubMed2001

Relations between decision-making deficits and discriminating contingencies following brain injury.

Deficits in decision-making characterized by failures to respond adaptively to consequences that follow responding are common following brain injury. To examine decision-making about consequences, individuals with and without acquired brain injury responded under different response-reinforcer contingencies. In two control conditions, reinforcement was contingent on responding and response repetition. Results showed responding (pressing four computer keys) by both groups produced similar amounts of reinforcement (money) and highlight equal sensitivity to money as a reinforcer. In subsequent experimental conditions, reinforcement was contingent upon varying responses. Results showed both groups produced variable response patterns, but injured subjects earned less reinforcement than controls. With instructions to vary responding across trials, injured subjects earned similar amounts of reinforcement as controls. Collectively, the results suggest reductions in sensitivity to contingencies may be present following injury and function as one behavioural mechanism of maladaptive decision-making.

Adult↗

PubMed2000

The effects of a vitamin supplement on the pica of a child with severe mental retardation.

The effects of a common multiple vitamin on the pica of a child with severe mental retardation and anemia were evaluated. A BAB design revealed that pica was decreased by the vitamin. The results suggest that pica can be effectively treated by implementation of a simple nutritional or biological intervention. Further research investigating the generality of this finding and the effects of combining biological and behavioral interventions are discussed.

Child↗

PubMed1999

Characteristics and outcomes of a home and community-based neurorehabilitation programme.

The potential clinical and financial advantages of providing neurorehabilitation directly in patients' homes and communities have recently been discussed. However, the specific characteristics and outcomes of a coordinated, interdisciplinary, home-based programme does not currently exist in the rehabilitation literature. The present paper presents patient demographics, type and intensity of services provided, satisfaction measures, and clinical outcomes for 77 brain injured individuals in an attempt to begin to define and evaluate this new level of care. Additionally, the challenges of conducting home-based rehabilitation, and needs for further research are discussed.

Adult↗

PubMed1994

What makes extinction work: an analysis of procedural form and function.

We examined methods for determining how extinction should be applied to different functions of self-injurious behavior (SIB). Assessment data indicated that the head banging of 3 children with developmental disabilities was maintained by different reinforcement contingencies: One subject's SIB was positively reinforced by attention from adults, the 2nd subjects SIB was negatively reinforced by escape from educational tasks, and the 3rd subject's SIB appeared to be automatically reinforced or "self-stimulatory" in nature. Three functional variations of extinction--EXT (attention), EXT (escape), and EXT (sensory)--were evaluated, and each subject was exposed to at least two of these variations in reversal or multiple baseline designs. Reductions in SIB were observed only when implementation of "extinction" involved the discontinuation of reinforcement previously shown to be responsible for maintaining the behavior. These results highlight important differences among treatment techniques based on the same behavioral principle (extinction) when applied to topographically similar but functionally dissimilar responses, and further illustrate the practical implications of a functional analysis of behavior disorders for designing, selecting, and classifying therapeutic interventions.

Attention↗

PubMed1994

The functions of self-injurious behavior: an experimental-epidemiological analysis.

Data are summarized from 152 single-subject analyses of the reinforcing functions of self-injurious behavior (SIB). Individuals with developmental disabilities referred for assessment and/or treatment over an 11-year period were exposed to a series of conditions in which the effects of antecedent and consequent events on SIB were examined systematically by way of multielement, reversal, or combined designs. Data were collected during approximately 4,000 experimental sessions (1,000 hr), with the length of assessment for individuals ranging from 8 to 66 sessions (M = 26.2) conducted over 2 to 16.5 hr (M = 6.5). Differential or uniformly high responding was observed in 145 (95.4%) of the cases. Social-negative reinforcement (escape from task demands or other sources of aversive stimulation) accounted for 58 cases, which was the largest proportion of the sample (38.1%). Social-positive reinforcement (either attention or access to food or materials) accounted for 40 (26.3%) of the cases, automatic (sensory) reinforcement accounted for 39 (25.7%), and multiple controlling variables accounted for 8 (5.3%). Seven sets of data (4.6%) showed either cyclical or inconsistent patterns of responding that were uninterpretable. Overall results indicated that functional analysis methodologies are extremely effective in identifying the environmental determinants of SIB on an individual basis and, subsequently, in guiding the process of treatment selection. Furthermore, an accumulation of assessment data from such analyses across a large number of individuals provides perhaps the most rigorous approach to an epidemiological study of behavioral function.

Adolescent↗

PubMed1994

Stimulus fading as treatment for obscenity in a brain-injured adult.

Obscene verbalizations of a person with traumatic brain injury were treated using stimulus fading as the singular form of intervention. Results of a functional assessment revealed that obscenity was maintained by negative reinforcement. Stimulus fading (initial elimination of instructional demands followed by their gradual reintroduction) produced immediate and substantial reductions in obscenity that were maintained as the frequency of demands increased to baseline levels. Potential applications of the use of antecedent treatment strategies are discussed.

Behavior Therapy↗

PubMed1993

Stimulus (instructional) fading during extinction of self-injurious escape behavior.

Three individuals with developmental disabilities were exposed to a series of assessment conditions to identify the source of reinforcement for their self-injurious behavior. In each case, self-injury occurred most often in instructional (demand) situations containing a brief time-out from the task contingent on self-injury, indicating that the behavior was an escape response (i.e., maintained by negative reinforcement). Treatment was implemented in a multiple baseline across subjects design and consisted of extinction (prevention of escape) plus instructional fading (initial elimination of instructions followed by their gradual reintroduction). Results showed that the combined treatment produced immediate and large reductions in self-injury that were maintained as the frequency of instructions was increased across sessions to match the original baseline rate of presentation. Results of a component analysis conducted with 1 subject suggested that stimulus fading accelerated the behavior-reducing effects of extinction.

Adolescent↗

PubMed1992

On the relationship between self-injurious behavior and self-restraint.

Many individuals who exhibit self-injurious behavior (SIB) also exhibit self-restraint. Three hypotheses about the determinants of self-restraint have been suggested: (a) Self-restraint is maintained by escape from or avoidance of aversive aspects of SIB, (b) self-restraint and SIB are members of the same functional class, and (c) self-restraint and SIB are functionally independent. This study examined a method by which the relationship between self-restraint and SIB may be investigated using functional analysis. Data were collected on the self-restraint and SIB exhibited by 5 mentally retarded males, while conditions suspected to maintain SIB were manipulated. Results suggested that self-restraint, like SIB, may be maintained by idiosyncratic contingencies. Implications of an understanding of self-restraint for the analysis and treatment of SIB are discussed, as are some general possibilities for future research.

Adolescent↗

PubMed1990

Nitrate Reduction in Response to CO(2)-Limited Photosynthesis : Relationship to Carbohydrate Supply and Nitrate Reductase Activity in Maize Seedlings.

The effects of CO(2)-limited photosynthesis on (15)NO(3) (-) uptake and reduction by maize (Zea mays, DeKalb XL-45) seedlings were examined in relation to concurrent effects of CO(2) stress on carbohydrate levels and in vitro nitrate reductase activities. During a 10-hour period in CO(2)-depleted air (30 microliters of CO(2)/ per liter), cumulative (15)NO(3) (-) uptake and reduction were restricted 22 and 82%, respectively, relative to control seedlings exposed to ambient air containing 450 microliters of CO(2) per liter. The comparable values for roots of decapitated maize seedlings, the shoots of which had previously been subjected to CO(2) stress, were 30 and 42%. The results demonstrate that reduction of entering nitrate by roots as well as shoots was regulated by concurrent photosynthesis. Although in vitro nitrate reductase activity of both tissues declined by 60% during a 10-hour period of CO(2) stress, the remaining activity was greatly in excess of that required to catalyze the measured rate of (15)NO(3) (-) reduction. Root respiration and soluble carbohydrate levels in root tissue were also decreased by CO(2) stress. Collectively, the results indicate that nitrate uptake and reduction were regulated by the supply of energy and carbon skeletons required to support these processes, rather than by the potential enzymatic capacity to catalyze nitrate reduction, as measured by in vitro nitrate reductase activity.

Journal Article↗

PubMed1990

Experimental analysis and extinction of self-injurious escape behavior.

Three studies are presented in which environmental correlates of self-injurious behavior were systematically examined and later used as the basis for treatment. In Study 1, 7 developmentally disabled subjects were exposed to a series of conditions designed to identify factors that maintain self-injurious behavior: attention contingent on self-injurious behavior (positive reinforcement), escape from or avoidance of demands contingent on self-injurious behaviour (negative reinforcement), alone (automatic reinforcement), and play (control). Results of a multielement design showed that each subject's self-injurious behavior occurred more frequently in the demand condition, suggesting that the behavior served an avoidance or escape function. Six of the 7 subjects participated in Study 2. During educational sessions, "escape extinction" was applied as treatment for their self-injurious behavior in a multiple baseline across subjects design. Results showed noticeable reduction or elimination of self-injurious behavior for each subject and an increase in compliance with instructions in all subjects for whom compliance data were taken. The 7th subject, whose self-injurious behavior during Study 1 occurred in response to medical demands (i.e., physical examinations), participated in Study 3. Treatment was comprised of extinction, as in Study 2, plus reinforcement for tolerance of the examination procedure, and was evaluated in a multiple baseline across settings design. Results showed that the treatment was successful in eliminating self-injurious behavior and that its effects transferred across eight new therapists and three physicians. General implications for the design, interpretation, and uses of assessment studies are discussed.

Adolescent↗

PubMed1990

Effects and side effects of DRO as treatment for self-injurious behavior.

A three-part controlled case study is presented in which severe and longstanding self-injurious behavior exhibited by a 9-year-old-boy was treated successfully with differential reinforcement of other behavior. In Phase 1, an experimental analysis demonstrated that the boy's scratching was not maintained by environmental contingencies; instead, it appeared that the self-injurious behavior was a stereotypic (automatically reinforced) response. In Phase 2, the effects of an escalating differential-reinforcement-of-other-behavior schedule mediated through token reinforcement (pennies) were evaluated in a reversal design. Results showed that differential-reinforcement-of-other-behavior eliminated self-injurious behavior very quickly and for periods of time as long as 30 min. A noteworthy side effect observed during Phase 2 was the occurrence of crying behavior following the nondelivery of reinforcement. In Phase 3, the token program was gradually extended in 30-min increments throughout the day. Additionally, results of a brief multielement manipulation showed that the effects of token reinforcement were superior to those of a more easily administered differential reinforcement of other behavior based on social reinforcement, which differed little from baseline.

Behavior Therapy↗

PubMed1990

The Self-Injury Trauma (SIT) Scale: a method for quantifying surface tissue damage caused by self-injurious behavior.

A method is described for classifying and quantifying surface tissue damage caused by self-injurious behavior. The Self-Injury Trauma Scale permits differentiation of self-injurious behavior according to topography, location of the injury on the body, type of injury, number of injuries, and estimate of severity. Fifty pairs of independently scored records were subjected to interrater reliability analyses, and the following mean (median) percentage agreement scores were obtained: overall agreement, 97% (98%); location of injury, 99% (100%); type of injury, 96% (100%); number of injuries, 89% (100%); and severity of injury, 94% (100%). Percentage agreement also was calculated for three summary scores: Number Index, 90%; Severity Index, 92%; and Estimate of Current Risk, 100%. Potential applications and limitations of the scale are discussed.

Adolescent↗

PubMed1987

Nitrate-induced changes in protein synthesis and translation of RNA in maize roots.

Nitrate regulation of protein synthesis and RNA translation in maize (Zea mays L. var B73) roots was examined, using in vivo labeling with [(35)S]methionine and in vitro translation. Nitrate enhanced the synthesis of a 31 kilodalton membrane polypeptide which was localized in a fraction enriched in tonoplast and/or endoplasmic reticulum membrane vesicles. The nitrate-enhanced synthesis was correlated with an acceleration of net nitrate uptake by seedlings during initial exposure to nitrate. Nitrate did not consistently enhance protein synthesis in other membrane fractions. Synthesis of up to four soluble polypeptides (21, 40, 90, and 168 kilodaltons) was also enhanced by nitrate. The most consistent enhancement was that of the 40 kilodalton polypeptide. No consistent nitrate-induced changes were noted in the organellar fraction (14,000g pellet of root homogenates). When roots were treated with nitrate, the amount of [(35)S]methionine increased in six in vitro translation products (21, 24, 41, 56, 66, and 90 kilodaltons). Nitrate treatment did not enhance accumulation of label in translation products with a molecular weight of 31,000 (corresponding to the identified nitrate-inducible membrane polypeptide). Incubation of in vitro translation products with root membranes caused changes in the SDS-PAGE profiles in the vicinity of 31 kilodaltons. The results suggest that the nitrate-inducible, 31 kilodalton polypeptide from a fraction enriched in tonoplast and/or endoplasmic reticulum may be involved in regulating nitrate accumulation by maize roots.

Journal Article↗

PubMed1986

Operant studies of self-injurious hand biting in the Rett syndrome.

Two children with Rett syndrome were treated for their self-injurious hand biting. Results of an operant assessment showed that in both cases the behavior functioned as a self-stimulatory response. Differential reinforcement, combined with a response interruption technique, produced large reductions in the hand biting of both girls and increases in the motor performance (instruction following, toy play) of one girl. These results suggest that further operant investigations may be helpful in the understanding and management of the behavioral symptoms found in Rett syndrome.

Bites, Human↗

PubMed1986

Stimulus fading and transfer in the treatment of self-restraint and self-injurious behavior.

We conducted several manipulations of mechanical restraint properties during the course of treatment for two profoundly retarded adolescents who exhibited both self-restraint and self-injurious behavior. In study 1, a combination of prompting, differential reinforcement, and stimulus fading reduced one subject's self-restraint, which consisted of holding rigid tubes on his arms. Subsequently, stimulus control of both self-restraint and self-injurious behavior was transferred to tennis wrist bands. In study 2, a second subject's self-restraint--placing his hands in his pants--was immediately eliminated by the use of air splints. Additionally, differential reinforcement and air-pressure fading resulted in the complete mobility of his arms and a substantial increase in appropriate behaviors. Results of this investigation suggest that stimulus fading and transfer may be valuable components in the elimination of self-restraint.

Adolescent↗

PubMed1985

Assessment of stimulus preference and reinforcer value with profoundly retarded individuals.

We evaluated a procedure for identifying potential reinforcers with profoundly retarded individuals. In Experiment 1, six persons were repeatedly exposed to 16 stimuli, and approach behaviors to each stimulus were used to identify preferred and nonpreferred stimuli. In Experiment 2, we examined the reinforcing properties of preferred and nonpreferred stimuli by delivering them contingently on the occurrence of arbitrarily selected responses. Results revealed that the preferred stimulus conditions typically produced higher rates of responding than did either the baseline or the nonpreferred stimulus conditions, suggesting that the procedure can be used to assess reinforcer value for individuals with limited behavioral repertoires.

Adolescent↗

PubMed1983

The role of elicited responding in the feature-positive effect.

Hearst and Jenkins proposed in 1974 that elicited responding accounts for the feature-positive effect. To test this position, pigeons were exposed to a feature-positive or feature-negative discrimination between successively presented displays--one consisted of a red and a green response key and the other consisted of two green response keys. There were four main conditions: 5-5 (5-sec trials, 5-sec intertrial intervals), 5-30, 30-30, and 30-180. Conditions 5-30 and 30-180 should produce the largest amount of elicited responding, and therefore the largest feature-positive effects. A response-independent bird was yoked to each response-dependent bird to allow direct assessment of the amount of elicited responding generated by each condition. Contrary to the predictions by Hearst and Jenkins's theory, response-dependent birds showed large feature-positive effects in each condition. The largest feature-positive effect was obtained in condition 5-5. Response-independent birds produced similar results, but manifested low response rates.

Animals↗