Objective: Prader-Willi syndrome (PWS) is a rare genetic disorder characterized by neonatal hypotonia, short stature, hyperphagia and obesity. It is the most common cause of genetic obesity. Most children with PWS have mild to moderate intellectual disabilities with an intelligence quotient (IQ) between 60 and 65. Preceding studies shows that individuals with low IQ showed poor motor performance and low compliance to exercise resulting in little effect of exercise program. Also, previous studies about exercise therapy for PWS included only mild to moderate intellectual disabilities. Therefore, we report our therapeutic experience of aerobic exercise in a PWS patient with severe intellectual disability.
Case description: A 9-year old boy visited our rehabilitation center for treatment of obesity. Body mass index (BMI) was measured 26.0 at the time. He had been diagnosed as PWS at the age of 2. At 6 years old, the level of his IQ was 30 indicating severe intellectual disability. When the patient was diagnosed with diabetes mellitus at 8 years old, his parents tried to lose his weight by diet control. However, weight control eventually ended in failure because of his obsessed behavior with eating which is commonly seen in PWS. It seemed to be hard to apply aerobic exercise due to parent’s overprotection and patient’s poor cooperation in treatment. After several times of persuading about safety of aerobic exercise and educating about nutrition by rehabilitation team, he finally underwent exercise tolerance test (ETT) and exercise was prescribed with 60~70% intensity of the maximal heart rate based on the ETT data. Body composition was measured by the bio-electrical impedance analysis method (Inbody 720, Biospace®, Seoul, Korea).
We planned exercise training once a week using treadmill with ECG monitoring which was performed for about 8 months (Fig. 1). ETT was conducted before aerobic exercise and 8 months later. We additionally recommeded home based aerobic exercise but he had hardly done due to poor compliance in spite of several times of education. There was no adverse event during aerobic exercise. Blood sugar was well controlled during aerobic exercise.
After 8 months of aerobic exercise, maximal METs, total exercise time (TET), peak oxygen consumption (VO2) and peak respiratory exchange ratio (RER) were increased (Table 1). Also, with regard to body composition, skeletal muscle mass was increased and body fat mass and percent body fat were decreased (Table 2).
Conclusion: Exercise capacity and body composition were improved in the PWS patient after aerobic exercise for 8 months. Even if there are some difficulty in doing exercise due to low cognition, long-period aerobic exercise would be an effective intervention for improvement of exercise capacity and body composition in PWS patients with severe intellectual disability. |
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Results of exercise tolerance test before and 8 months after beginning aerobic exercise
Results of body composition analysis before and 8 months after beginning aerobic exercise
This figure shows treadmill walking with hemodynamic monitoring; (A) Exercise tolerance test, (B) Exercise with monitoring
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