Motor improvement in children with PMM2-CDG syndrome following a six-month rehabilitation treatment utilising whole-body vibration; a retrospective study.

OBJECTIVE: The aim of this study was to assess the effect of a six-month interval rehabilitation treatment on motor function of children with PMM2-CDG syndrome (#212065 Congenital disorder of glycosylation, Type Ia; CDG1A, OMIM catalogue number). METHODS: The concept 'Auf die Beine' (Center for Prevention and Rehabilitation of the University of Cologne, Germany) combines two short inpatient stays (1 to 2 weeks) with a six-month whole-body vibration (WBV) home-training program. 13 patients with PMM2-CDG syndrome participated in this concept from 2006 until 2015. Assessments at start, six months and 12 months (follow-up): Gross Motor Function Measure (GMFM-66), One-Minute Walk Test (1MWT) and instrumented gait analyses. RESULTS: The GMFM-66 (9 of 13 children) improved by 5.3 (mean) points (SD 3.2) at 12 months (p=0.0039). The 1MWT (6 of 13 children) improved by 19.17 meter (SD 16.51) after 12 months (p=0.0313). Gait analysis (9 of 13 children) measured by pathlength/distance ratio improved by -0.8 (SD 1.9) at 12 months (p=0.0195). CONCLUSION: Patients with PMM2-CDG syndrome benefit from the interval rehabilitation program 'Auf die Beine' including WBV.

Using artificial intelligence-based technologies to detect clinically relevant changes of gross motor function in children with cerebral palsy.

AIM: To compare the 66-item Gross Motor Function Measure (GMFM-66) with the reduced version of the GMFM-66 (rGMFM-66) with respect to the detection of clinically relevant changes in gross motor function in children with cerebral palsy (CP). METHOD: The study was a retrospective single centre analysis of children with CP who participated in a rehabilitation programme. Overall, 1352 pairs of GMFM-66 and rGMFM66 measurements with a time interval of 5 to 7 months were available. To measure clinically relevant changes in gross motor function, the individual effect size (iES) was calculated. RESULTS: The study population consisted of 1352 children (539 females), mean age 6 years 4 months (SD 2 years 4 months). The iES based on the GMFM-66 and the rGMFM-66 showed a significant correlation (r = 0.84, p < 0.001). The analysis of the area under the receiver operating characteristic curve showed an excellent agreement for clinically relevant gross motor improvement (Cohen's d ≥ 0.5; area under the curve = 0.90 [95% confidence interval 0.88-0.92]) or deterioration (Cohen's d ≤ -0.5; area under the curve = 0.95 [95% confidence interval 0.92-0.97]). INTERPRETATION: Performing the rGMFM-66 saves time compared to the full GMFM-66. The rGMFM-66 showed good agreement with the GMFM-66 with respect to the detection of clinically relevant changes in gross motor function in children with CP, so its use in everyday clinical practice seems justifiable. WHAT THIS PAPER ADDS: The reduced version of the 66-item Gross Motor Function Measure (rGMFM-66) detects clinically relevant changes in gross motor function in children with cerebral palsy. The rGMFM-66 correlates highly with the full GMFM-66. The rGMFM-66 can be used in clinical practice when the time schedule is limited.

Multivariable reference centiles for maximum grip strength in childhood to young adults.

OBJECTIVES: Maximum grip strength (mGS) is a useful predictor of health-related outcomes in children and adults. The aim of the study was to generate sex- and age-adjusted reference centiles for mGS for children, adolescents and young adults, while adjusting for body height and body mass index (BMI). METHODS: A retrospective analysis of longitudinal data from children and young adults participating in the DOrtmund Nutritional and Anthropometric Longitudinally Designed (DONALD) study (single center, open cohort study) from 2004 to 2022 was conducted. To generate sex-, age-, height- and BMI-adjusted reference centiles, a new algorithm combining multiple linear regression and the LMS method was conducted. RESULTS: Overall, 3325 measurements of mGS of 465 females and 511 males were eligible. The mean age at measurement of females was 12.6 ± 3.9 years, mean age of males was 12.4 ± 4.7 years. The median of number of repeated measurements per individual was 3 (range 1-8). The mGS was significantly (p < 0.001) correlated to body height and BMI (r = 0.303-0.432). Additional reference centiles for the change of z-scores of mGS were generated for children and young adults from 8 to 20 years. CONCLUSIONS: We proposed to evaluate mGS in children, adolescents and young adults with the presented reference centiles adjusted to sex, age, height and BMI. The method presented may also be applicable to other biological variables that depend more than just on sex and age. For the first time, also reference centiles to assess the change of mGS in repeated measurements were presented.

Effect of Whole-body Vibration frequency on muscle tensile state during graded plantar flexor isometric contractions.

Background: Acute physiological and biomechanical alterations have been reported following whole-body vibration (WBV). Stiffening of muscles has only been anecdotally reported in response to WBV. Accordingly, this study investigated active plantar flexor muscle stiffness in response to a single WBV bout at four mechanical vibration frequencies. Methods: Thirteen healthy adults (37.1 ± 14.4 years old) randomly received WBV in 4 different frequencies (6, 12, 24, and 0 Hz control) for 5 min. Shear wave speed (SWS) in longitudinal and transverse projections, architecture, and electric muscle activity were recorded in the medial gastrocnemius (MG) and soleus (SOL) muscle during graded plantar flexor contraction. Subjective rating of perceived muscle stiffness was assessed via Likert-scale. Results: SWS of the MG at rest was enhanced in response to 5 min of 24 Hz WBV (p = 0.025), while a small reduction in SOL SWS was found during contraction (p = 0.005) in the longitudinal view. Subjective stiffness rating was increased following 12 Hz intervention. After 24 Hz WBV, pennation angle for MG was decreased (p = 0.011) during contraction. As a secondary finding, plantar flexor strength was significantly increased with each visit, which, however, did not affect the study's main outcome because of balanced sequence allocation. Conclusion: SWS effects were solely limited to 24 Hz mechanical vibration and in the longitudinal projection. The observed effects are compatible with an interpretation by post-activation potentiation, warm-up, and force-distribution within the triceps surae muscles following 5 min WBV. The outcome may suggest SWS as a useful tool for assessing acute changes in muscle stiffness.

Jumping Mechanography: Reference Centiles in Childhood and Introduction of the Nerve-Muscle Index to Quantify Motor Efficiency.

Jumping mechanography provides robust motor function indicators among children. The study aim was to develop centiles for the single 2-leg jump (S2LJ) in German children and adolescents and to identify differences in children with obesity. Data were collected in 2004-2021 through the German DOrtmund Nutritional and Anthropometric Longitudinally Designed (DONALD) study. All participants (6-18 years, mean age 11.4) performed annually an S2LJ aiming for maximum height on a Ground Reaction Force Platform. LMS (lambda-mu-sigma), including resampling, was used to develop centiles for velocity (vmax), jump height (hmax), relative force (Fmax/BW), relative power (Pmax/mass), impulse asymmetry and a new parameter to describe jump efficiency, the Nerve-Muscle Index (NMI), defined as vmax/(Fmax/BW). Data from 882 children and adolescents were analyzed (3062 measurements, median 3 per individual). In females, Fmax/BW values were higher in younger age but remained constant in adolescence. vmax, hmax and Pmax/mass increased in childhood, reaching a plateau in adolescence. In males, vmax, hmax and Pmax/mass showed a constant increase and the Fmax/BW remained lower. Children with obesity showed lower Fmax/BW, hmax, vmax and the NMI, hence, lower velocity per relative force unit and less efficient jump. The centiles should be used to monitor motor development in childhood. The NMI is a surrogate for motor efficiency.

Improved Enzyme Replacement Therapy with Cipaglucosidase Alfa/Miglustat in Infantile Pompe Disease.

Pompe disease is a lysosomal storage disorder with impaired glycogen degradation caused by a deficiency of the enzyme acid α-glucosidase (GAA). Children with the severe infantile form do not survive beyond the first year of life without treatment. Since 2006, enzyme replacement therapy (ERT) with Alglucosidase alfa (Myozyme) has been available, which is a recombinant human GAA (rhGAA). Myozyme therapy has prolonged the life span of affected patients, but many patients showed a continuing, albeit slower, disease progression. A new generation of rhGAA, Cipaglucosidase alfa (Amicus) has a higher content of mannose-6-phosphate residues, which are necessary for efficient cellular uptake and lysosomal targeting. Cipaglucosidase alfa is co-administered with an enzyme stabilizer, Miglustat, which also optimizes the pharmacological properties. In mouse models, the superiority of Cipaglucosidase alfa/Miglustat compared to the previous standard therapy could be determined. Here, we report the disease course of a patient with severe infantile M. Pompe, who showed serious progression even with high-dose standard of care ERT. Changing the therapy to Cipaglucosidase alfa/Miglustat improved respiratory failure, cardiomyopathy, and motor functions significantly. The patient could be weaned from respiratory support and oxygen supplementation. Cardiac function was normalized. Most impressively, the patient, who had lost nearly all motor skills, acquired head control, learned to speak, and could move his wheelchair by himself. Overall, the patient's clinical situation has improved dramatically with the new ERT.

Effect of systemic isotretinoin therapy on semen parameters.

PURPOSE: Vitamin A has multiple functions in the human body, being involved in growth, epithelial differentiation, vision, immune function and reproduction. While normal spermatogenesis is influenced by several factors, it requires vitamin A. Systemic isotretinoin is a vitamin A derivative that is used in the treatment of many dermatological diseases, especially acne vulgaris (AV). There is limited research on the changes in semen parameters after systemic isotretinoin therapy in humans. Our study investigates the presence of varicoceles in patients undergoing systemic isotretinoin therapy for AV and examines whether there were any changes in the semen parameters before and after treatment. METHODS: Included in the study were 46 men patients who were scheduled for systemic isotretinoin therapy for AV. Before treatment, the patients underwent a physical examination and ultrasonography for varicoceles assessment. The patients underwent spermiogram before treatment and after 6 months of treatment. The spermiogram assessments included semen volume, sperm concentration, total sperm count, progressive motility, viability and sperm morphology. RESULTS: After treatment, there was an increase in semen volume, sperm concentration, total sperm count, progressive motility and vitality from the pre-treatment values, but a deterioration in the sperm morphology (p < .05). Comparing patients with and without varicoceles revealed more changes in semen parameters after treatment in those with varicoceles. There was a statistically significant difference in sperm concentration (p < .001). CONCLUSIONS: Systemic isotretinoin therapy negatively affects sperm morphology, but has positive effect on other semen parameters, and these changes in semen parameters occur more frequently in patients with varicoceles.KEY MESSAGESAcne vulgaris is a very common disease and systemic isotretinoin is used as the most effective agent in its treatment.Systemic isotretinoin positively affects semen parameters except sperm morphology.Changes in semen parameters are more common in patients with varicocele.

Effectiveness of surface polishing after debonding of metal brackets from different CAD-CAM materials.

PURPOSE: The purposes of this study were to compare and evaluate the surface texture of different restorative computer-aided design and computer-aided manufacturing (CAD/CAM) materials before bonding and after debonding of metal orthodontic brackets. MATERIALS AND METHODS: A total of 60 rectangular ceramic test specimens (n = 20 in each group) were prepared using feldspathic ceramic blocks (FLD; served as control), hybrid ceramic blocks (HC), and lithium disilicate ceramic blocks (LDC). Surface roughness (Ra) analysis was conducted using a profilometer before bonding the metal brackets. After the debonding and polishing procedures, a second surface roughness analysis was conducted on each specimen. The shear bond strength (SBS) test was applied to each specimen using a universal test machine for debonding the metal brackets. The debonded specimens were examined under a stereomicroscope and scored using a 4-step adhesive remnant index (ARI). The Ra and SBS values and the ARI scores were saved, and the data were analyzed statistically at a significance level of 0.05. One specimen from each group was examined under atomic force microscopy to visualize surface roughness. Furthermore, one specimen from each group was additionally prepared for scanning electron microscopy analysis. RESULTS: Statistically significant differences in SBS measurements were observed between all three groups. The highest SBS values were obtained from the FLD group, the lowest from the LDC group. The HC group showed significantly (P = 0.001) lower Ra values than the LDC and FLD groups after debonding and polishing. No significant differences were observed in the ARI scores between the groups. CONCLUSIONS: Hybrid ceramics could be a suitable alternative for fixed restorations in adult patients receiving subsequent treatments with fixed orthodontic appliances.

Predicting Gross Motor Function in Children and Adolescents with Cerebral Palsy Applying Artificial Intelligence Using Data on Assistive Devices.

Data obtained from routine clinical care find increasing use in a scientific context. Many routine databases, e.g., from health insurance providers, include records of medical devices and therapies, but not on motor function, such as the frequently used Gross Motor Function Measure-66 (GMFM-66) score for children and adolescents with cerebral palsy (CP). However, motor function is the most common outcome of therapeutic efforts. In order to increase the usability of available records, the aim of this study was to predict the GMFM-66 score from the medical devices used by a patient with CP. For this purpose, we developed the Medical Device Score Calculator (MDSC) based on the analysis of a population of 1581 children and adolescents with CP. Several machine learning algorithms were compared for predicting the GMFM-66 score. The random forest algorithm proved to be the most accurate with a concordance correlation coefficient (Lin) of 0.75 (0.71; 0.78) with a mean absolute error of 7.74 (7.15; 8.33) and a root mean square error of 10.1 (9.51; 10.8). Our findings suggest that the MDSC is appropriate for estimating the GMFM-66 score in sufficiently large patient groups for scientific purposes, such as comparison or efficacy of different therapies. The MDSC is not suitable for the individual assessment of a child or adolescent with CP.

Changes in cardiovascular risk factors among children and young adults with type 1 diabetes during the COVID-19 pandemic compared to previous years-Results from the German DPV registry.

BACKGROUND: The diverse stages of the COVID-19 pandemic led to several social circumstances that influenced daily life and health behavior. PURPOSE: To evaluate changes in cardiovascular risk factors and physical activity among children and young adults with type 1 diabetes (T1D) during the COVID-19 pandemic in Germany compared to previous years. METHODS: A total of 32 785 individuals aged 6-21 years at baseline with T1D from the German diabetes patient follow-up (DPV) registry contributed data on 101 484 person-years between 2016 and 2021. The first treatment year of each individual within this period was considered as baseline. Based on trends from 2016 to 2019, we estimated differences in body mass index-SD score (BMI-SDS), blood pressure (BP-SDS), and lipid levels (non-high-density lipoprotein [non-HDL]) between observed and predicted estimates for the years 2020 and 2021 using linear regression analysis standardized for age, diabetes duration, sex, and migratory background. The proportion doing organized sports and smoking cigarettes was analyzed using multivariable logistic regression models. RESULTS: BMI-SDS increased constantly from 2016 to 2021 without a significant increase above expected values for 2020/2021. Systolic BP-SDS (difference observed vs. expected with 95% confidence interval, 2020: 0.10 [0.07-0.14], 2021: 0.17 [0.14-0.20]) and non-HDL (2020: 2.7 [1.3-4.1] mg/dl, 2021: 4.1 [2.7-5.5] mg/dl) were significantly increased (all p < .001) in both pandemic years. The proportion of subjects participating in organized sports was reduced from over 70% in prepandemic years to 35%-65% in diverse stages/waves of the COVID-19 pandemic. The percentage smoking cigarettes did not change. CONCLUSIONS: We describe an increase in BP and atherogenic lipid levels coinciding with a reduction in physical activity but no acceleration of the prepandemic increases in BMI-SDS among young people with T1D during the COVID-19 pandemic.

Vibration assisted rehabilitation in patients with Pompe disease: A case series.

The results of three cases with infantile-onset Pompe disease participating in a rehabilitation program with home-based vibration training will be presented. In this retrospective observational case study, the cases participated in the neuromuscular training program "Auf die Beine", which combines two blocks of intensive, goal directed training with 6 months of home-based whole body vibration (WBV). Assessments by the means of a dual-energy X-ray absorptiometry and grip strength were applied at multiple points throughout the program. Two cases showed an increase in lean mass index of +0.319 kg/m2, +0.721 kg/m2 and bone mineral content of +0.028 kg/m2, +0.031 kg/m2 over one year. Additionally physiotherapeutic therapy goals could be achieved. In the remaining child lean mass index did not change, bone mineral content decreased by -0.03 kg. The neuromuscular rehabilitation program "Auf die Beine" has shown to be safe and effective in two of three cases for muscle and bone mass gain as well as in achievement of physiotherapeutic goals. To summarize, WBV is an innovative therapy in a rehabilitation concept, which might be helpful in Pompe disease, but further studies with larger cohorts are needed.

Body Fat Distribution in Children and Adolescents With Cerebral Palsy.

To evaluate the body fat distribution in children with cerebral palsy (CP). The present study focusses on a monocentric retrospective analysis of body fat distribution from children diagnosed with CP. The children participated in a rehabilitation program. Reference centiles were calculated based on data from the National Health and Nutrition Examination Survey (NHANES, 1999-2004). Z-scores for trunk-to-leg fat ratio were calculated. Further, fat mass index (FMI) was evaluated based on percentiles that have already been published. 237 males and 194 females with CP were considered (mean age: 11 years and 11 months [SD 3 years]). These were compared to 1059 males and 796 females from the NHANES (mean age: 14 years and 7 months [SD 3 years and 4 months]). The z-scores for trunk-to-leg fat ratio showed the following values: mean -0.47 (SD 1.50) for males, -0.49 (SD 1.11), for females, -0.48 (SD 1.34) for all. The z-scores for FMI showed the following values: mean -0.29 (SD 0.70) for males, -0.88 (SD 2.0) for females, -0.55 (SD 1.46) for all. The results showed rather a gynoid fat distribution and a lower FMI in children with CP than in the reference population (NHANES 1999-2004).

Diagnostic Evaluation of the Functional Muscle-Bone Unit in Children With Cerebral Palsy With and Without Low Trauma Fractures.

Children and adolescents with cerebral palsy (CP) are at increased risk of low trauma fractures (LTF) due to low bone mineral content (BMC). The risk of LTFs might be overestimated by only age - and sex adjusted Z-scores for BMC because Z-score based DXA techniques do not take into account other relevant parameters like height, muscle and fat mass. This study aimed to present an update of the functional muscle-bone unit-algorithm (uFMBU-A) to evaluate bone health in children with CP in order to predict the risk of LTF taking into account the parameters sex, age, height, muscle and fat mass. We performed a monocentric retrospective analysis of 177 DXA-scans of children and adolescents with CP aged 8-19. Six of these 177 patients had sustained at least 1 LTF. Age-, sex- and size adjusted Z-scores of total body less head (TBLH)-BMC, lean body mass and fat mass were calculated. The uFMBU-A was applied to the study group and results were compared with established Z-score based DXA-measurements and algorithm based diagnostic techniques concerning the prediction of LTF risk. The uFMBU-A had the greatest diagnostic odds ratio (13.3 [95% CI 2.41; 72.9]) of the evaluated predictors with a sensitivity of 50.0% (95% CI 11.8; 88.2), specifity of 93% (95% CI 88.1; 96.3). The uFMBU-A was the most accurate method of the evaluated parameters to predict LTF in children with CP and is recommended when evaluating bone health.

Reference centiles of bone mineral density, and body composition of lower limbs in children and adolescents for Hologic DXA Discovery model A.

Background: Regional Dual-energy X-ray absorptiometry (DXA) assessments are useful for patients where whole body measurements are not feasible due to positioning difficulties because of anatomic anomalies (e.g. severe scoliosis) and artifacts due to neuroorthopedic hardware. Until now, there is a lack of reference centiles of bone mineral density and body composition of lower limbs for the DXA device Hologic Discovery model A densitometer. The study aimed to generate age-and sex specific reference centiles of bone mineral content (BMC), bone mineral density (BMD), lean body mass (LBM), and fat mass (FM) of the lower limbs of children and adolescents of Hologic DXA system (Discovery model A). Methodology: Data from children and adolescents aged 8-20 years of the National Health and Nutrition Examination Survey (NHANES) of the years 2015-2018 were used to create age-specific and sex-specific reference centiles. Study population was subdivided into three ethnic groups (non-Hispanic Black, non-Hispanic White and Mexican-American). The LMS method was used to calculate the reference centiles. Study population was adjusted concerning the BMI. Results: A total of DXA scans of 769 non-Hispanic Black children (386 females), 937 non-Hispanic White children (447 females) and 692 Mexican-American children (370 females) were used to calculate age-specific and sex-specific reference curves. 881 DXA scans had to be excluded because of extreme BMI values of the study population, leaving 513 non-Hispanic Black (205 females), 346 Mexican-American children (179 females), 658 Non-Hispanic White (282 females) for statistical analysis and creating age-and sex specific reference centiles after BMI adjustment. Conclusions: We presented pediatric reference centiles for regional bone mineral density, bone mineral content, lean body mass and fat mass of the lower limbs which were age-and sex-specific for three ethnic groups (Mexican-American, non-Hispanic Black and non-Hispanic-White). The reference centiles can be used for the Hologic DXA system Discovery model A with the software version 3.2.

Interaction between fat- and muscle development in children and adolescents.

Background: Prevalence of obesity increased noticeably during the last decades. Little is known so far about the association between fat accumulation due to obesity and skeletal muscle mass. The aim of this study was to describe the association between fat mass and muscle mass after adjusting for relevant confounding factors in the National Health and Nutrition Examination Survey (NHANES) study population of children and adolescents. We postulated a negative correlation between fat mass and lean body mass. Methodology: A total of 849 whole body DXA-scans of the NHANES study population of children and adolescents aged eight to twenty years of the years 1999-2004 were eligible for statistical analysis. Appendicular lean body mass (appLBM) was used to evaluate muscle mass. Bivariate analysis (Pearson's correlation coefficient), multiple linear regression analysis and mediation analysis were performed. The multiple regression analysis and mediation analysis were adjusted for weight, age height, sex ethnicity and physical activity. Results: Fat mass correlates with appendicular lean body mass (Pearons's r 0.336, p < 0.001). In the multiple linear regression analysis the regression coefficient between appLBM and FM was positive (0.204; p < 0.001), when considering appendicular lean body mass, fat mass and body weight, the regression coefficient was negative (-0.517; p < 0.001). Conclusions: Study results indicate a negative association of fat mass and skeletal muscle mass in children and adolescents, when weight, age, height, sex ethnicity and physical activity are considered. Further investigations are needed to evaluate if there is a biochemical interaction between fat cells and muscle cells that could explain this effect.

Pediatric Reference Centiles of Bone Mineral Density and Body Composition of Lower Limbs.

Localized neurological diseases such as spina bifida are often accompanied by normal upper limb and spinal bone mineral density (BMD), whereas regional BMD of the lower limbs may be decreased. Therefore, regional BMD measurements may be more accurate to quantify regional bone health. Until now, no pediatric reference centiles of bone mineral density and body composition of the lower extremities are available for Hologic DXA systems. The objective was to generate age-and sex specific reference centiles of DXA scans of lower limbs for Hologic DXA systems. Data from the National Health and Nutrition Examination Survey of the period 1999-2004 (age 8 - 20 years) were used to generate age-specific and sex-specific reference centiles for the non-Hispanic Black, non-Hispanic White and Mexican-American NHANES study population. The LMS method was used to calculate the reference centiles. Data of DXA scans of 2233 non-Hispanic black children (880 females), 1869 non-Hispanic white children (803 females) and 2350 Mexican American children (925 females) were used to create age-specific and sex-specific reference curves. We presented age-and sex-specific reference centiles for regional bone mineral density, bone mineral content, lean body mass and fat mass at the lower limbs for children and adolescents which were ethnicity specific and directly applicable to Hologic QDR-4500A fan-beam densitometer.

Artificial intelligence to improve efficiency of administration of gross motor function assessment in children with cerebral palsy.

AIM: To create a reduced version of the 66-item Gross Motor Function Measure (rGMFM-66) using innovative artificial intelligence methods to improve efficiency of administration of the GMFM-66. METHOD: This study was undertaken using information from an existing data set of children with cerebral palsy participating in a rehabilitation programme. Different self-learning approaches (random forest, support vector machine [SVM], and artificial neural network) were evaluated to estimate the GMFM-66 score with the fewest possible test items. Test agreements were evaluated (among other statistics) by intraclass correlation coefficients (ICCs). RESULTS: Overall, 1217 GMFM-66 assessments (509 females, mean age 8y 10mo [SD 3y 9mo]) at a single time and 187 GMFM-66 assessments and reassessments (80 females, mean age 8y 5mo [SD 3y 10mo]) after 1 year were evaluated. The model with SVM predicted the GMFM-66 scores most accurately. The ICCs of the rGMFM-66 and the full GMFM-66 were 0.997 (95% confidence interval [CI] 0.996-0.997) at a single time and 0.993 (95% CI 0.993-0.995) for the evaluation of the change over time. INTERPRETATION: The study shows that the efficiency of the full GMFM-66 assessment can be increased by using machine learning (self-learning algorithms). The presented rGMFM-66 score showed an excellent agreement with the full GMFM-66 score when applied to a single assessment and when evaluating the change over time.

Effects of long-term immobilisation on endomysium of the soleus muscle in humans.

NEW FINDINGS: What is the central question of this study? While muscle fibre atrophy in response to immobilisation has been extensively examined, intramuscular connective tissue, particularly endomysium, has been largely neglected: does endomysium content of the soleus muscle increase during bed rest? What is the main finding and its importance? Absolute endomysium content did not change, and previous studies reporting an increase are explicable by muscle fibre atrophy. It must be expected that even a relative connective tissue accumulation will lead to an increase in muscle stiffness. ABSTRACT: Muscle fibres atrophy during conditions of disuse. Whilst animal data suggest an increase in endomysium content with disuse, that information is not available for humans. We hypothesised that endomysium content increases during immobilisation. To test this hypothesis, biopsy samples of the soleus muscle obtained from 21 volunteers who underwent 60 days of bed rest were analysed using immunofluorescence-labelled laminin γ-1 to delineate individual muscle fibres as well as the endomysium space. The endomysium-to-fibre-area ratio (EFAr, as a percentage) was assessed as a measure related to stiffness, and the endomysium-to-fibre-number ratio (EFNr) was calculated to determine whether any increase in EFAr was absolute, or could be attributed to muscle fibre shrinkage. As expected, we found muscle fibre atrophy (P = 0.0031) that amounted to shrinkage by 16.6% (SD 28.2%) on day 55 of bed rest. ENAr increased on day 55 of bed rest (P < 0.001). However, when analysing EFNr, no effect of bed rest was found (P = 0.62). These results demonstrate that an increase in EFAr is likely to be a direct effect of muscle fibre atrophy. Based on the assumption that the total number of muscle fibres remains unchanged during 55 days of bed rest, this implies that the absolute amount of connective tissue in the soleus muscle remained unchanged. The increased relative endomysium content, however, could be functionally related to an increase in muscle stiffness.

Association of muscle mass and fat mass on low-density-lipoprotein cholesterol and triglyceride plasma concentration in children and adolescents.

OBJECTIVES: Obesity has often been associated with high low-density-lipoprotein cholesterol (LDL-C) and triglyceride plasma concentrations, known risk factors for diabetes mellitus and cardiovascular disease. Study objective was to evaluate the association of LDL-C and triglyceride plasma concentration with muscle and fat mass in children and adolescents. METHODS: We analyzed data of the National Health and Nutrition Examination Survey (1999-2004) to estimate lean muscle and fat mass assessed by dual-energy X-ray absorptiometry (DXA) of participants whose lipid profiles had been examined. Fat mass was operationalized by DXA-determined fat mass index (FMI). Muscle mass was assessed by appendicular lean mass index (aLMI). High LDL-C and triglyceride concentration was defined as above 130 mg/dL. RESULTS: For the evaluation of the association of LDL-C and triglyceride plasma concentration with LMI and FMI Z-scores, the data of 2,487 children and adolescents (age 8-19 years) (984 females) were eligible. High aLMI showed no association with LDL-C or triglyceride concentration, but high FMI showed significant association with LDL-C and triglyceride plasma concentration in the bivariate regression analysis. CONCLUSIONS: Isolated muscle mass increase may not be protective against high LDL-C and triglycerides plasma levels in children and adolescents. Thus, exercise may lead to risk factor reduction mainly through fat mass reduction.

Reference Centiles to Monitor the 6-minute-walk Test in Ambulant Children with Cerebral Palsy and Identification of Effects after Rehabilitation Utilizing Whole-body Vibration.

Background: Children with cerebral palsy present age-driven development in gross motor skills and walking capacity. Aims: To precisely monitor the 6-minute walk test (6MWT) in children with CP, GMFCS levels 1 and 2 over 6 months and to assess the effect of a 6-month rehabilitation program including whole-body vibration. Methods: Retrospective analysis of data of 157 children with CP who received standardized rehabilitation (DRKS00011331). 6MWT was assessed at the start (M0) and end of the training (M6), as well as at a 6-month follow-up (M12). Centiles were created using the lambda-mu-sigma (LMS) method. Results: We created 6MWT percentiles using data of all 157 children (M0 data). A medium treatment effect size (Cohen's d = 0.69) was found (M6 and M12 data). Conclusions: The generated centiles may help monitor 6MWT changes over 6 months. Combining WBV and conventional physiotherapy can significantly improve 6MWT in children with CP. Abbreviations: 6MWT: 6-Minute Walk Test; CP: Cerebral palsy; ES: effect size; GMFCS: Gross Motor Function Classification System; GMFM-66: Gross Motor Function Measure 66; LOESS: locally weighted scatterplot smoothing; LMS: lambda-mu-sigma; MCID: minimal clinical important difference; SD: standard deviation; SRM: standardized response mean; WBV: whole-body vibration.