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| Research on Behavioral Characteristics of the Prader-Willi Syndrome |
| Sunday, May 28, 2006 |
| 9:00 AM–10:20 AM |
| Centennial Ballroom IV |
| Area: DDA; Domain: Applied Research |
| Chair: Brian A. Iwata (University of Florida) |
| CE Instructor: Brian A. Iwata, Ph.D. |
| Abstract: This symposium provides an overview of the Prader-Willi Syndrome (PWS) and summarizes research related to three of its major behavioral characteristics: food preference (poor diet), exercise, and self-injurious behavior. |
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| Overview of the Prader-Willi Syndrome. |
| STEVE DRAGO (Alachua County Association for Retarded Citizens) |
| Abstract: This presentation will provide a general description of the Prader-Willi Syndrome (PWS) and the clinical context for the current research. PWS is a genetic disorder associated with mild mental retardation and a variety of clinical and behavioral features. The most striking behavioral characteristic of PWS is hyperphagia (overeating), which leads to extreme obesity and life-threatening complications, including hypertension, heart disease, and diabetes. The UF-ARC project provides residential and vocational services to approximately 50 individuals with PWS, making it one of the largest in the country. Two unique features of the program include its extensive use of behavioral technology across all aspects of service delivery and its emphasis on research as the basis for program development and revision. |
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| Determinants of Food Preference in Individuals with Prader-Willi Syndrome. |
| JESSICA L. THOMASON (University of Florida), Brian A. Iwata (University of Florida), Pamela L. Neidert (University of Florida), Claudia L. Dozier (University of Florida) |
| Abstract: Previous research has shown that several characteristics of reinforcers and their delivery, including quality, magnitude, delay, etc., may affect preference. We examined the influence of those characteristics on food preferences in individuals with Prader-Willi Syndrome (PWS), a genetic disorder in which excessive food consumption is a major problem behavior. Preference assessments were conducted initially to identify foods that were of “high quality” (highly preferred). Next, baseline sessions were conducted to examine behavioral sensitivity to reinforcer quality, magnitude, and delay. Two response options were available; one response was associated with the optimum value of a characteristic; the second response was associated with a lower value of a characteristic (e.g., one response resulted in immediate reinforcer delivery; the other response resulted in delayed reinforcer delivery). The relative influence of each characteristic on responding was evaluated during a final phase, in which the values of two characteristics were simultaneously manipulated, and response allocation was measured. Results are discussed in terms of implications for the assessment and treatment of dietary management and food-related problem behaviors. |
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| Descriptive and Experimental Research on Exercise in the Prader-Willi Syndrome. |
| CLAUDIA L. DOZIER (University of Florida), Brian A. Iwata (University of Florida), Jessica L. Thomason (University of Florida), Pamela L. Neidert (University of Florida) |
| Abstract: Physical exercise is an important therapeutic intervention in the management of life-threatening obesity, a prominent clinical feature of Prader-Willi Syndrome (PWS). To date, however, very few studies have been conducted on the occurrence of physical exercise in individuals with PWS. We conducted a descriptive study initially to identify types of physical activity (e.g., sitting, laying down, walking, running, cleaning) exhibited by individuals with and without PWS throughout their daily routines. We subsequently evaluated the effects of a reinforcement contingency to increase the frequency of exercise by individuals with PWS. Of particular interest was an assessment of the utility of conjugate reinforcement schedules as maintenance procedures. Access to preferred activities (music, television) was available under conjugate or more traditional ratio schedules, and both performance and preference were examined. Results of this comparison are discussed with respect to the use of non-food interventions to increase the occurrence of exercise for individuals diagnosed with PWS. |
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| Prevalence and Functions of Self-injurious Behavior in the Prader-Willi Syndrome. |
| PAMELA L. NEIDERT (University of Florida), Brian A. Iwata (University of Florida), Claudia L. Dozier (University of Florida), Jessica L. Thomason (University of Florida) |
| Abstract: It has been noted that individuals with Prader-Willi Syndrome (PWS) often engage in self-injurious behavior. The most commonly reported form of SIB is skin picking (Dykens & Shah, 2003). In the current study, we established the prevalence, frequency, and severity of SIB in individuals with PWS by way of a structured questionnaire sent to all providers registered with the National Prader-Willi Syndrome Association of the USA. Second, we conducted experimental analyses to identify the functional characteristics of SIB in a sample of PWS individuals. Results are discussed in terms of form and function of SIB in individuals with PWS, as well as the implications these findings have for treatment development. |
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