Examination of sensory reception and integration abilities in children with and without Prader-Willi syndrome.

BACKGROUND: Good postural stability control is dependent upon the complex integration of incoming sensory information (visual, somatosensory, vestibular) with neuromotor responses that are constructed in advance of a voluntary action or in response to an unexpected perturbation. AIMS: To examine whether differences exist in how sensory inputs are used to control standing balance in children with and without Prader-Willi syndrome (PWS). METHODS AND PROCEDURES: In this cross-sectional study, 18 children with PWS and 51 children categorized as obese but without PWS (without PWS) ages 8-11 completed the Sensory Organization Test®. This test measures the relative contributions of vision, somatosensory, and vestibular inputs to the control of standing balance. The composite equilibrium score (CES) derived from performance in all sensory conditions, in addition to equilibrium scores (EQs) and falls per condition were compared between groups. OUTCOMES AND RESULTS: The CES was lower for children with PWS compared to children without PWS (M=53.93, SD=14.56 vs. M=66.17, SD=9.89, p = .001) while EQs declined in both groups between conditions 1 and 4 (F (1.305, 66.577) = 71.381, p < .001). No group differences in the percent of falls were evident in condition 5 but more children with PWS fell in condition 6 (χ2 (1) = 7.468, p = .006). Group differences in frequency of repeated falls also approached significance in conditions 5 (χ2 (3) = 4.630, p = .099) and 6 (χ2 (3) = 5.167, p = .076). CONCLUSIONS AND IMPLICATIONS: Children with PWS demonstrated a lower overall level of postural control and increased sway when compared to children with obesity. Both the higher incidence and repeated nature of falls in children with PWS in conditions 5 and 6 suggest an inability to adapt to sensory conditions in which vestibular input must be prioritized. Postural control training programs in this population should include activities that improve their ability to appropriately weight sensory information in changing sensory environments, with a particular focus on the vestibular system. WHAT DOES THIS STUDY ADD?: This study shows that children with PWS demonstrate a lower level of postural stability. The results suggest that children with PWS show inability to adapt to sensory conditions that require prioritizing vestibular information to maintain postural control. This information can be used to help guide training programs in this population.

Improved Motor Proficiency and Quality of Life in Youth With Prader-Willi Syndrome and Obesity 6 Months After Completing a Parent-Led, Game-Based Intervention.

PURPOSE: To determine changes and potential differences in physical activity (PA), gross motor proficiency (MP), and health parameters after a 6-month follow-up (FU) period following participation in a parent-led PA intervention in youth with or without Prader-Willi syndrome (PWS). METHODS: About 42 youth with PWS and 65 youth without PWS but with obesity (body fat percentage >95th percentile for age and sex), aged 8-16 years, participated. The intervention included preplanned PA sessions containing playground and console-based video games scheduled 4 days per week for 24 weeks. Families received training and curriculum materials. PA (accelerometry), MP (Bruininks-Oseretsky Test of MP), and health-related quality of life were obtained before (PRE), after completing the intervention (POST), and at FU. RESULTS: There were no significant changes in PA at any time point. At FU and POST, participants showed higher bilateral coordination (PRE = 9.3 [0.4], POST = 11.7 [0.5], and FU = 11.1 [0.6]); speed and agility (PRE = 9.2 [0.4], POST = 10.8 [0.4], and FU = 11.5 [0.5]); and strength (PRE = 8.0 [0.3], POST = 9.2 [0.3], and FU = 9.2 [0.3]) than at PRE. At FU (80.3 [2.1]) and POST (79.8 [1.7]), youth without PWS showed higher health-related quality of life than PRE (75.0 [1.8]). CONCLUSION: The improvements in MP and health-related quality of life at FU suggest long-term durability of intervention outcomes.

A 24-Week Physical Activity Intervention Increases Bone Mineral Content without Changes in Bone Markers in Youth with PWS.

Bone mineral density (BMD) is of concern in Prader-Willi syndrome (PWS). This study compared responses to a physical activity intervention in bone parameters and remodeling markers in youth with PWS (n = 45) and youth with non-syndromic obesity (NSO; n = 66). Measurements occurred at baseline (PRE) and after 24 weeks (POST) of a home-based active games intervention with strengthening and jumping exercises (intervention group = I) or after a no-intervention period (control group = C). Dual x-ray absorptiometry scans of the hip and lumbar spine (L1-L4) determined BMD and bone mineral content (BMC). Bone markers included fasting bone-specific alkaline phosphatase (BAP) and C-terminal telopeptide of type I collagen (CTx). Both I and C groups increased their hip BMD and BMC (p < 0.001). Youth with PWS-I increased their spine BMC from PRE to POST (p < 0.001) but not youth with PWS-C (p = 1.000). Youth with NSO (I and C) increased their spine BMC between PRE and POST (all p < 0.001). Youth with PWS showed lower BAP (108.28 ± 9.19 vs. 139.07 ± 6.41 U/L; p = 0.006) and similar CTx (2.07 ± 0.11 vs.1.84 ± 0.14 ng/dL; p = 0.193) than those with NSO regardless of time. Likely, the novelty of the intervention exercises for those with PWS contributed to gains in spine BMC beyond growth. Bone remodeling markers were unaltered by the intervention.

Changes in Health-Related Outcomes in Youth With Obesity in Response to a Home-Based Parent-Led Physical Activity Program.

PURPOSE: The purpose of this study was to elucidate whether implementation of a parent-led physical activity (PA) curriculum improved health parameters in youth with obesity. METHODS: This prospective study included 45 youth with Prader-Willi syndrome (PWS) and 66 youth classified as obese without PWS. Participants were quasi-randomly assigned to an intervention (I) group which completed PA sessions (25-45+ minutes long) 4 days/week for 24 weeks or to a control (C) group. Generalized estimating equations analyzed differences in body composition, PA, and health-related quality of life (HRQL) by youth group, time, and treatment group. A secondary analysis in the I-group compared outcomes based on whether youth showed increases (n = 12) or decreases (n = 19) of ≥2 minutes of moderate-to-vigorous PA (MVPA). RESULTS: Body mass index increased from baseline to 24 weeks in youth with obesity (p = .032) but not in youth with PWS. There were no changes in MVPA, total PA, or body fat indicators over time. The I-group demonstrated an increase of 7.2% and 7.6% in social and school HRQL, respectively, and a 3.3% improvement in total HRQL. Youth in the I-group who increased MVPA demonstrated decreased body mass (p = .010), body mass index z-score (p = .018), and body fat mass (p = .011); these changes were not observed in those who decreased MVPA over time. CONCLUSIONS: Participation in a parent-led PA intervention at home can positively influence HRQL in youth with obesity and/or PWS. Increases in MVPA ≥2 minutes above baseline led to decreases in body mass and fat, while maintaining lean mass.

Hormonal and Metabolic Responses to a Single Bout of Resistance Exercise in Prader-Willi Syndrome
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BACKGROUND: Prader-Willi syndrome (PWS) is characterized by excessive adiposity. Excess adiposity negatively affects hormonal and metabolic responses to aerobic exercise. This study determined whether PWS and/or adiposity affected hormonal and metabolic responses to resistance exercise. METHODS: Eleven children with PWS (11.4 ± 3.1 years, 43.9 ± 7.5% body fat), 12 lean children (9.3 ± 1.4 years, 18.3 ± 4.9% body fat), and 13 obese children (9.6 ± 1.3 years, 40.3 ± 5.2% body fat) participated. The children stepped onto an elevated platform while wearing a weighted vest for 6 sets of 10 repetitions per leg (sets separated by 1 min of rest). For the children with PWS, the platform height was 23.0 cm and vest load was computed as (20% of stature × 50% of lean body mass)/23.0 cm. For the controls, the platform height was 20% of the stature and vest load 50% of the lean body mass. Blood samples were obtained before, immediately after, and during recovery from exercise (+15, +30, and +60 min). RESULTS: All groups had similar catecholamine, insulin, and glucagon responses. The groups showed no major differences in glucose and lactate levels. The PWS children demonstrated earlier increases in fatty acids during recovery and higher glycerol and ketone levels than the controls. CONCLUSION: The PWS children demonstrated largely intact hormonal, glycolytic, and lipolytic responses to lower-body resistance exercise. In PWS, elevated ketone levels suggest an incomplete fat oxidation.
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Association between physical activity and bone in children with Prader-Willi syndrome.

BACKGROUND: The aim of the study was to determine if physical activity (PA) is associated with bone health in children with Prader-Willi syndrome (PWS). METHODS: Participants included 23 children with PWS (age: 11.0±2.0 years). PA, measured by accelerometry, was categorized into light, moderate, vigorous and moderate plus vigorous intensities. Hip, total body minus the head (body), bone mineral content (BMC), bone mineral density (BMD) and BMD z-score (BMDz) were measured by dual X-ray absorptiometry. Separate hierarchical regression models were completed for all bone parameters, PA intensity and select covariates. RESULTS: Moderate PA and select covariates explained the most variance in hip BMC (84.0%), BMD (61.3%) and BMDz (34.9%; p<0.05 for all). Likewise, for each body parameter, moderate PA and select covariates explained the most variance in body BMC (75.8%), BMD (74.4%) and BMDz (31.8%; p<0.05 for all). CONCLUSIONS: PA of at least moderate intensity appears important for BMC and BMD in children with PWS.

Obesity and Prader-Willi Syndrome Affect Heart Rate Recovery from Dynamic Resistance Exercise in Youth.

Following exercise, heart rate decline is initially driven by parasympathetic reactivation and later by sympathetic withdrawal. Obesity delays endurance exercise heart rate recovery (HRR) in both children and adults. Young people with Prader-Willi Syndrome (PWS), a congenital cause for obesity, have shown a slower 60-s endurance exercise HRR compared to lean and obese children, suggesting compromised regulation. This study further evaluated effects of obesity and PWS on resistance exercise HRR at 30 and 60 s in children. PWS (8-18 years) and lean and obese controls (8-11 years) completed a weighted step-up protocol (six sets x 10 reps per leg, separated by one-minute rest), standardized using participant stature and lean body mass. HRR was evaluated by calculated HRR value (HRRV = difference between HR at test termination and 30 (HRRV30) and 60 (HRRV60) s post-exercise). PWS and obese had a smaller HRRV30 than lean (p < 0.01 for both). Additionally, PWS had a smaller HRRV60 than lean and obese (p = 0.01 for both). Obesity appears to delay early parasympathetic reactivation, which occurs within 30 s following resistance exercise. However, the continued HRR delay at 60 s in PWS may be explained by either blunted parasympathetic nervous system reactivation, delayed sympathetic withdrawal and/or poor cardiovascular fitness.

Nutritional intakes in children with Prader-Willi syndrome and non-congenital obesity.

BACKGROUND: Individuals with Prader-Willi syndrome (PWS) have extremely regulated diets to prevent the development of morbid obesity. OBJECTIVE: This study evaluated potential deficiencies in macro and micronutrients in a cohort of youth with PWS and compared them to a group of children with non-congenital obesity and to US national recommendations. DESIGN: Participants were 32 youth with PWS (age=10.8±2.6 years, body fat=46.7±10.1%) and 48 children without PWS but classified as obese (age=9.7±1.2 years, body fat=43.4±5.7%). Participants' parents completed a training session on food recording before completing a 3-day food record during a typical week including a weekend day and two weekdays, as well as a screening form indicating nutritional supplements use. RESULTS: Youth with PWS reported less calories (1,312±75 vs. 1,531±61 kcal, p=0.03), carbohydrate (175±10 vs. 203±8 g), and sugars (67±5 vs. 81±4 g; p=0.04 for both) than obese. Youth with PWS consumed more vegetables (1.1±0.1 vs. 0.6±0.1 cups) and more of them met the daily recommendation (p<0.01 for both). Likewise, youth with PWS consumed more calcium than obese (899±53 vs. 752±43 mg) and more of them met the recommended daily dose (p=0.04 for both). The majority of participants in this study did not meet the vitamin D recommendation. CONCLUSION: Despite consuming less calories, youth with PWS had a similar proportion of macronutrients in their diet as children with obesity. Micronutrient deficiencies in calcium and vitamin D in youth with PWS were noted despite a third of youth with PWS consuming multivitamin supplements. Special attention must be paid to the diets of youth with PWS and with obesity to ensure they are meeting micronutrient needs during this period of growth and development.

Hormonal and metabolic responses to endurance exercise in children with Prader-Willi syndrome and non-syndromic obesity.

OBJECTIVE: Excess adiposity affects endocrine and metabolic function at rest and during exercise. This study evaluated the endocrine and metabolic responses to exercise in syndromic (Prader-Willi syndrome) and non-syndromic pediatric obesity. MATERIALS/METHODS: Eleven PWS (10.9±1.6 y, 45.4±9.5% body fat), 12 lean (9.4±1.2 y, 17.5±4.6% body fat), and 12 obese (9.2±1.2 y, 39.9±6.8% body fat) children completed ten two-minute cycling exercise bouts, separated by one-minute rest. Blood samples were obtained at rest pre-exercise (PRE), immediately post-exercise (IP), and 15, 30 and 60 minutes into recovery. Samples were analyzed for hormones and metabolites. RESULTS: Growth hormone increased in response to exercise in lean and obese but not PWS (IP>PRE; IP: lean>obese). Epinephrine increased with exercise in lean (IP>PRE), while norepinephrine increased in lean and obese (IP>PRE) but not PWS; no differences were observed between lean and obese groups at IP. No other significant hormonal group interactions existed. Glucose, lactate, free fatty acid, glycerol and ketone responses were similar among groups. CONCLUSION: PWS children exhibited altered stress hormone responses to exercise. However, glucose-regulating hormones and metabolic responses to exercise appeared normal.

Hormonal and metabolic responses to a resistance exercise protocol in lean children, obese children and lean adults.

During childhood, varying exercise modalities are recommended to stimulate normal growth, development, and health. This project investigated hormonal and metabolic responses triggered by a resistance exercise protocol in lean children (age: 9.3 ± 1.4 y, body fat: 18.3 ± 4.9%), obese children (age: 9.6 ± 1.3 y, body fat: 40.3 ± 5.2%) and lean adults (age: 23.3 ± 2.4 y, body fat: 12.7 ± 2.9%). The protocol consisted of stepping onto a raised platform (height = 20% of stature) while wearing a weighted vest (resistance = 50% of lean body mass). Participants completed 6 sets of 10 repetitions per leg with a 1-min rest period between sets. Blood samples were obtained at rest preexercise, immediately postexercise and 2 times throughout the 1-hr recovery to analyze possible changes in hormones and metabolites. Children-adult differences included a larger exercise-induced norepinephrine increase in adults vs. children and a decrease in glucagon in children but not adults. Similarities between adults and children were observed for GH-IGF-1 axis responses. Metabolically, children presented with lower glycolytic and increased fat metabolism after exercise than adults did. Obesity in childhood negatively influenced GH, insulin, and glucose concentrations. While adults occasionally differed from children, amount of activated lean mass, not maturation, likely drove these dissimilarities.

Patterns of habitual physical activity in youth with and without Prader-Willi Syndrome.

Children classified as overweight or obese and those with disabilities are at a greater risk of not meeting the minimum recommendation of 60 min a day of moderate to vigorous physical activity (PA). Youth with Prader-Willi Syndrome (PWS) appear to participate in less PA compared to nonsyndromal children, likely due to syndrome-related factors. However, description of PA patterns in youth with PWS is lacking. The purpose of this study was to characterize PA in youth with PWS and to compare it to PA in children with nonsyndromal obesity. Twenty-four youth with PWS (ages 8-16 years) and 40 obese children without PWS (OB) (ages 8-11 years) wore accelerometers for eight consecutive days. Data were screened for compliance and classified into PA intensities: sedentary behavior (SED), light (LPA), moderate (MPA), vigorous (VPA) and moderate plus vigorous (MVPA). Youth with PWS spent 19.4% less time in weekly LPA (p=0.007) and 29.8% less time in weekly VPA compared to OB controls (p=0.036). All other intensities were similar between groups. In addition, PWS participated in less LPA and VPA during the weekends compared to OB, and less LPA on weekdays when compared to OB. There was also a trend towards PWS participating in less MVPA during the weekends and less VPA during the weekends than OB controls. There was a trend towards PWS participating in less VPA on weekends compared to weekdays, while OB participated similarly in VPA on weekdays and weekend days. On average, neither PWS nor OB children met minimum MVPA recommendations. The results suggest there is a need to design exercise programs for PWS youth that focus on integrating vigorous intensity activities, especially during the weekends when structured PA may not be available.

Effects of adiposity and Prader-Willi Syndrome on postexercise heart rate recovery.

Heart rate recovery (HRR) is an indicator of all-cause mortality in children and adults. We aimed to determine the effect of adiposity and Prader-Willi Syndrome (PWS), a congenital form of obesity, on HRR. Sixteen children of normal weight (NW = body fat % ≤85th percentile, 9.4 ± 1.1 y), 18 children with obesity (OB = body fat % >95th percentile, 9.3 ± 1.1 y), and 11 PWS youth (regardless of body fat %; 11.4 ± 2.5 y) completed peak and submaximal bike tests on separate visits. HRR was recorded one minute following peak and submaximal exercises. All groups displayed similar HRR from peak exercise, while NW (54 ± 16 beats) and OB (50 ± 12 beats) exhibited a significantly faster HRR from submaximal exercise than PWS (37 ± 14 beats). These data suggest that excess adiposity does not influence HRR in children, but other factors such as low cardiovascular fitness and/or autonomic dysfunction might be more influential.