Lower Motor Performance Research Articles

Glucose and glycogen levels in piglets that differ in birth weight and vitality

In the pig, intrauterine crowding can greatly affect postnatal characteristics, among which birth weight and locomotion. In a previous study, we discovered that piglets with a low birth weight/low vitality (L piglets) have a reduced motor performance compared to piglets with a normal birth weight/normal vitality (N piglets). A possible explanation is that L piglets lack the energy to increase their motor performance to the level of that of N piglets. Blood glucose levels (GLU) and glycogen concentrations in skeletal muscle of the front (GLYFRONT) and hind leg (GLYHIND) and the liver (GLYLIVER) at birth and during the first 96 h postpartum were compared between L and N piglets. GLU at birth was the same for both groups. After birth, GLU immediately increased in N piglets, whereas it only increased after 8 h in L piglets. L piglets showed a lower GLYHIND at birth and did not use this glycogen during the first 8 h postpartum, while N piglets showed a gradual depletion. GLYLIVER at birth was 50% lower for L piglets and was unused during the studied period while N piglets consumed half of their GLYLIVER during the first 8 h. Based on these results, it is possible that lower glycogen concentrations at birth, the delayed increase in GLU and the lower use of glycogen during the first 8 h after birth negatively affect motor performance in L piglets. However, based on this study, it is unclear whether the low mobilization of glycogen by L piglets is a consequence, rather than a cause of their lower motor performance.

The effect of mirror therapy combined with motor imagery therapy on lower extremity motor function and balance early after ischemic stroke

Objective To investigate the effect of the mirror therapy (MT) combined with motor imagery therapy (MIT) on the lower limb motor performance, balance and ability in the activities of daily living of ischemic stroke patients soon after a stroke. Methods Forty hospitalized ischemic stroke patients were randomly allocated to an MT+ MIT group (n=20) or an MIT only group (n=20). In addition to routine rehabilitation, the MIT group exercised practicing knee extension and ankle dorsiflexion 30 minutes a day, five days a week for 8 weeks following motor imagery therapy protocols, while the MT+ MIT group accepted MIT combined with mirror therapy. The Fugl-Meyer lower extremity assessment (FMA-LE), Berg Balance scores (BBSs) and the Modified Barthel index (MBI) were used to evaluate the effects of the treatment before the treatment and after 4 and 8 weeks of therapy. Results Before the intervention there was no significant difference between the two groups in terms of their average FMA, BBS and MBI ratings. After 4 weeks of treatment a significant improvement was observed in the MT+ MIT group′s average FMA-LE and BBS scores and in the flat walking component of the MBI. In the MIT group only the average bed/wheelchair transfer and flat walking scores in the MBI were significantly improved. After 8 weeks the MT+ MIT group′s average FMA-LE and BBS scores had improved significantly, along with its average scores in the feeding, dressing, grooming, bathing, urination, bed/wheelchair transfer, walking up and down stairs and flat walking components of the MBI. In the MIT group the average FMA-LE and BBS scores had improved significantly, along with those for bed/wheelchair transfer, walking up and down stairs and flat walking in the MBI. After both 4 and 8 weeks, the MT+ MIT group′s average scores were consistently significantly better than those of the MT group. Conclusion Mirror therapy can significantly enhance the effectiveness of motor imagery therapy when they are combined in the rehabilitation of ischemic stroke patients in the early post-stroke stage. Key words: Mirror therapy; Motor imagery therapy; Ischemic stroke; Motor control

The effect of gamma tACS over the M1 region and cerebellar hemisphere does not depend on current intensity

Transcranial alternating current stimulation (tACS) has been shown to modulate neural connectivity in the cortical area under experimental electrodes. Although gamma tACS over the M1 region and the cerebellar hemisphere has been shown to improve motor performance, the optimal stimulation method has not been clarified. In this study, we aimed to clarify whether the effect of gamma tACS over M1 and the cerebellar hemisphere depends on current intensity. Twenty healthy adults performed a visuomotor control task using their right index finger for 30 s during tACS (70 Hz) over the left M1 and the right cerebellar hemisphere. Each subject participated in 10 trials, separated by intervals of 3 min. Three stimulation conditions were applied: (1) pseudo-stimulation (sham condition), (2) tACS with a current intensity of 1.0 mA and (3) tACS with a current intensity of 2.0 mA. Our results indicated that regardless of the current intensity, participants with the lower motor performance had better motor performance under both tACS conditions. Such a correlation was not observed under the sham condition. Collectively, our findings demonstrated that the effect of gamma tACS over M1 and the cerebellar hemisphere does not depend on current intensity, and that motor performance slightly improved in both tACS conditions for participants with lower motor performance.

Motor development’s curves of premature infants on the first year of life according to Alberta Infant Motor Scale

Abstract Introduction: The motor trajectory of pre-term children is an important indicator of health during infancy, since alterations may be a signal for the need of professional intervention. Objective: To describe percentiles and motor development curves for Brazilian preterm infants in the first year of life, determining the reference values for categorization of motor performance assessed by the AIMS. Methods: Participated in this cross-sectional study 976 children born pre-term, newly-born to 12 months of corrected age. The Alberta Infant Motor Scale (AIMS) was used to assess participants’ motor development. The scores of the Brazilian norms were used as comparison criteria. Results: Children born pre-term showed lower scores compared to children born full-term indicating the need for a specific percentile curve for that population. The scores differentiated at P1 to P99 percentiles allowing for the categorization of children with typical development, at risk and with atypical development. At 0, 4, 8, 9, 10, 11 and 12 months an overlapping of extreme percentiles (P1, P5 and P10; P90, P95 and P99) was observed, but not in the other percentiles. Conclusion: The percentiles described indicate that preterm children presented lower motor performance than full-term children and AIMS has discriminant power for the clinical evaluation of these children. The developmental curves showed lower capacity for behavioral differentiation in the extreme percentiles.

Altered Gamma Oscillations during Motor Control in Children with Autism Spectrum Disorder.

Autism is hypothesized to result in a cortical excitatory and inhibitory imbalance driven by inhibitory interneuron dysfunction, which is associated with the generation of gamma oscillations. On the other hand, impaired motor control has been widely reported in autism. However, no study has focused on the gamma oscillations during motor control in autism. In the present study, we investigated the motor-related gamma oscillations in autism using magnetoencephalography. Magnetoencephalographic signals were recorded from 14 right-handed human children with autism (5 female), aged 5–7 years, and age- and IQ-matched 15 typically developing children during a motor task using their right index finger. Consistent with previous studies, the autism group showed a significantly longer button response time and reduced amplitude of motor-evoked magnetic fields. We observed that the autism group exhibited a low peak frequency of motor-related gamma oscillations from the contralateral primary motor cortex, and these were associated with the severity of autism symptoms. The autism group showed a reduced power of motor-related gamma oscillations in the bilateral primary motor cortex. A linear discriminant analysis using the button response time and gamma oscillations showed a high classification performance (86.2% accuracy). The alterations of the gamma oscillations in autism might reflect the cortical excitatory and inhibitory imbalance. Our findings provide an important clue into the behavioral and neurophysiological alterations in autism and a potential biomarker for autism.SIGNIFICANCE STATEMENT Currently, the diagnosis of autism has been based on behavioral assessments, and a crucial issue in the diagnosis of autism is to identify objective and quantifiable clinical biomarkers. A key hypothesis of the neurophysiology of autism is an excitatory and inhibitory imbalance in the brain, which is associated with the generation of gamma oscillations. On the other hand, motor deficits have also been widely reported in autism. This is the first study to demonstrate low motor performance and altered motor-related gamma oscillations in autism, reflecting a brain excitatory and inhibitory imbalance. Using these behavioral and neurophysiological parameters, we classified autism and control group with good accuracy. This work provides important information on behavioral and neurophysiological alterations in patients with autism.

Transcranial Alternating Current Stimulation With Gamma Oscillations Over the Primary Motor Cortex and Cerebellar Hemisphere Improved Visuomotor Performance.

Transcranial alternating current stimulation (tACS) can be used to modulate oscillatory brain activity. In this study, we investigated whether tACS applied over the primary motor cortex (M1) and cerebellar cortex region improved motor performance. We applied tACS (1.0 mA) to 20 healthy adults while they performed an isometric force task with some visuomotor control using their right index finger. Gamma (70 Hz) oscillations in the Experiment 1 or beta (20 Hz) oscillations in the Experiment 2 were applied for 30 s over the left M1, right cerebellar hemisphere or both regions (“M1-Cerebellum”), and errors performing the task were compared. Beta-oscillation tACS did not affect motor performance. With the gamma-oscillation tACS, a negative correlation was found between the difference of error in the M1-Cerebellum condition and the number of errors in the sham condition (P = 0.005, Pearson’s r = −0.597), indicating that motor performance improved with M1-Cerebellum tACS for subjects with low motor performance in the sham condition. Those who performed poorly in the sham condition made significantly fewer errors with M1-Cerebellum tACS (P = 0.004). Thus, for subjects with poorer motor performance, tACS with gamma oscillations applied over the M1 and contralateral cerebellar hemisphere improved their performance.

Motor development in infancy is related to cognitive function at 4 years of age

Evidence is accumulating that motor and cognitive development are interrelated. This study investigates associations between motor development in infancy and cognitive function at 4 years of age. This study is part of the Groningen prospective cohort study on the development of children born after assisted reproductive techniques such as in vitro fertilization. The study group consisted of 223 children (119 males, 104 females) born to subfertile couples (median gestational age 39.6wks, range 30-43wks). Motor behaviour was assessed with the Infant Motor Profile (IMP) at 4 months, 10 months, and 18 months. IQ was evaluated at 4 years with the Kaufman Assessment Battery for Children, Second Edition. Latent class growth modelling was used to analyse relations between IMP and IQ scores. Infants with low total IMP scores had an IQ that was 8.9 points lower at 4 years than infants with typical IMP scores (95% confidence interval 3.6-14.1). Also, low scores in the domains of variation and performance were associated with a lower IQ at 4 years of age, by 6.1 points and 13.2 points respectively. Motor development in relatively low-risk infants is associated with cognition at 4 years of age. In particular, low motor variation and performance are associated with a lower IQ at 4 years of age. Motor development in infancy is directly related to cognitive function at 4 years of age. This relationship is most pronounced for infant motor variation and performance. The size of the differences in IQ is clinically relevant.

A new motor screening assessment for children at risk for motor disorders: construct validity

To develop a motor screening assessment and provide preliminary evidence of its psychometric properties. A sample of 365 elementary school students was assessed, with structural equation modeling applied to obtain evidence of the adequacy of the factor structure of the motor screening assessment. As well, differential item functioning was used to evaluate whether various identifiable subgroups of children (i.e., sex and grade) perform particular tasks differently. Overall, girls obtained higher scores than boys while, for both sexes, the assessment scores increased with age. Furthermore, differential item function analysis revealed that the precision of the test was highest for those with moderate to low motor performance, suggesting that this tool would be appropriate for identifying individuals with movement difficulties. Although further tests of its psychometric properties are required, the motor screening assessment appears to be a reliable, valid, and quickly-administered tool for screening children's movements.

Abnormalities of Vital Signs in Children with Cerebral Palsy: Relationship to Physical Disabilities

The autonomic functions of children with cerebral palsy (CP) have not been sufficiently explored, and corresponding abnormalities are underdiagnosed. In addition, studies evaluating the associations between autonomic dysfunctions and the different aspects of motor performance among these children are scarce. We aimed to investigate vital signs in children with CP and compare them to those of children with typical motor development (TMD) and to determine the associations of autonomic dysfunction with the demographic and clinical data and motor characteristics of these children. A convenience sample of 118 children with CP was evaluated in this cross-sectional study. A group of 69 matched children with TMD served as a control group. We measured the vital signs and key pinch and hand grip strengths of all children in the study. Vital signs were recorded while the children rested in a comfortable sitting position. Children with CP were evaluated for muscle tone and motor abilities. Systolic BP, diastolic BP, heart rate, and respiratory rate were significantly higher in children with CP than in children with TMD (p values of 0.03, 0.006, 0.02, and 0.001, respectively), while blood oxygen saturation and oral body temperature were significantly lower (p values of 0.00 and 0.003, respectively). We detected only weak to moderate correlations between some vital sign abnormalities and children with lower motor performance (diplegic and quadriplegic children, children with level IV or V on the gross motor function classification system (GMFCS), and children with low key pinch and hand grip strength). Children with CP had abnormalities in their vital signs at rest, reflecting a state of dysautonomia. Abnormalities included high systolic BP, diastolic BP, heart rate, and respiratory rate and low blood oxygen saturation and oral body temperature. Children with lower motor performance were at a greater risk of dysautonomia.

Abnormal Gray Matter Shape, Thickness, and Volume in the Motor Cortico-Subcortical Loop in Idiopathic Rapid Eye Movement Sleep Behavior Disorder: Association with Clinical and Motor Features.

Idiopathic rapid eye movement sleep behavior disorder (iRBD) is a major risk factor for Parkinson's disease and dementia with Lewy bodies. Anatomical gray matter abnormalities in the motor cortico-subcortical loop areas remain under studied in iRBD patients. We acquired T1-weighted images and administrated quantitative motor tasks in 41 patients with polysomnography-confirmed iRBD and 41 healthy subjects. Cortical thickness and voxel-based morphometry (VBM) analyses were performed to investigate local cortical thickness and gray matter volume changes, vertex-based shape analysis to investigate shape of subcortical structures, and structure-based volumetric analyses to investigate volumes of subcortical and brainstem structures. Cortical thickness analysis revealed thinning in iRBD patients in bilateral medial superior frontal, orbitofrontal, anterior cingulate cortices, and the right dorsolateral primary motor cortex. VBM results showed lower gray matter volume in iRBD patients in the frontal lobes, anterior cingulate gyri, and caudate nucleus. Shape analysis revealed extensive surface contraction in the external and internal segments of the left pallidum. Clinical and motor impaired features in iRBD were associated with anomalies of the motor cortico-subcortical loop. In summary, iRBD patients showed numerous gray matter structural abnormalities in the motor cortico-subcortical loop, which are associated with lower motor performance and clinical manifestations of iRBD.

Deficits in Coordinative Bimanual Timing Precision in Children With Specific Language Impairment.

Our objective was to delineate components of motor performance in specific language impairment (SLI); specifically, whether deficits in timing precision in one effector (unimanual tapping) and in two effectors (bimanual clapping) are observed in young children with SLI. Twenty-seven 4- to 5-year-old children with SLI and 21 age-matched peers with typical language development participated. All children engaged in a unimanual tapping and a bimanual clapping timing task. Standard measures of language and motor performance were also obtained. No group differences in timing variability were observed in the unimanual tapping task. However, compared with typically developing peers, children with SLI were more variable in their timing precision in the bimanual clapping task. Nine of the children with SLI performed greater than 1 SD below the mean on a standardized motor assessment. The children with low motor performance showed the same profile as observed across all children with SLI, with unaffected unimanual and impaired bimanual timing precision. Although unimanual timing is unaffected, children with SLI show a deficit in timing that requires bimanual coordination. We propose that the timing deficits observed in children with SLI are associated with the increased demands inherent in bimanual performance.

SUN-PP223: Reduced Lean Body Mass Within School Children With Normal BMI is Associated with Low Gross Motor Performance

SUN-PP223: Reduced Lean Body Mass Within School Children With Normal BMI is Associated with Low Gross Motor Performance

Brain-controlled functional electrical stimulation therapy for gait rehabilitation after stroke: a safety study.

BackgroundMany stroke survivors have significant long-term gait impairment, often involving foot drop. Current physiotherapies provide limited recovery. Orthoses substitute for ankle strength, but they provide no lasting therapeutic effect. Brain-computer interface (BCI)-controlled functional electrical stimulation (FES) is a novel rehabilitative approach that may generate permanent neurological improvements. This study explores the safety and feasibility of a foot-drop-targeted BCI-FES physiotherapy in chronic stroke survivors.MethodsSubjects (n = 9) operated an electroencephalogram-based BCI-FES system for foot dorsiflexion in 12 one-hour sessions over four weeks. Gait speed, dorsiflexion active range of motion (AROM), six-minute walk distance (6MWD), and Fugl-Meyer leg motor (FM-LM) scores were assessed before, during, and after therapy. The primary safety outcome measure was the proportion of subjects that deteriorated in gait speed by ≥0.16 m/s at one week or four weeks post-therapy. The secondary outcome measures were the proportion of subjects that experienced a clinically relevant decrease in dorsiflexion AROM (≥2.5°), 6MWD (≥20 %), and FM-LM score (≥10 %) at either post-therapy assessment.ResultsNo subjects (0/9) experienced a clinically significant deterioration in gait speed, dorsiflexion AROM, 6MWT distance, or FM-LM score at either post-therapy assessment. Five subjects demonstrated a detectable increase (≥0.06 m/s) in gait speed, three subjects demonstrated a detectable increase (≥2.5°) in dorsiflexion AROM, five subjects demonstrated a detectable increase (≥10 %) in 6MWD, and three subjects demonstrated a detectable increase (≥10 %) in FM-LM. Five of the six subjects that exhibited a detectable increase in either post-therapy gait speed or 6MWD also exhibited significant (p < 0.01 using a Mann–Whitney U test) increases in electroencephalogram event-related synchronization/desynchronization. Additionally, two subjects experienced a clinically important increase (≥0.16 m/s) in gait speed, and four subjects experienced a clinically important increase (≥20 %) in 6MWD. Linear mixed models of gait speed, dorsiflexion AROM, 6MWD, and FM-LM scores suggest that BCI-FES therapy is associated with an increase in lower motor performance at a statistically, yet not clinically, significant level.ConclusionBCI-FES therapy is safe. If it is shown to improve post-stroke gait function in future studies, it could provide a new gait rehabilitation option for severely impaired patients. Formal clinical trials are warranted.Electronic supplementary materialThe online version of this article (doi:10.1186/s12984-015-0050-4) contains supplementary material, which is available to authorized users.

Strenght and power in children with low motor performance scores: A descriptive analysis

This study aimed to explore descriptive average values of strength and explosive power tasks in children with LMP scores, and individually analyze their strength and power outputs with age progression. Twenty-four children were tested on the Movement Assessment Battery for Children (MABC-2). Five children scored below the 15th percentile (10.8±1.7 yrs) and were placed in the LMP group (n = 5). Nineteen children (10.7±1.7 yrs) were included on the TD group (n =19). Participants isometric, isokinetic and handgrip strength and explosive power were tested. The group of children with LMP presented inferior descriptive mean scores as compared to the group with TD children at knee isometric and isokinetic, handgrip, long jump and vertical jump tests. In addition, the results demonstrated that strength and power increase with age for those children with LMP. The findings suggest that children with LMP may be delayed in developing strength and power, which may be affecting their ability to perform gross and fine motor skills at the same level as their TD peers. We recommend that intervention programs for children with LMP include specific motor tasks and exercises focusing on neuromuscular coordination as well as ability to manage muscle strength and power levels.

Handedness and developmental coordination disorder in Portuguese children: Study with the M-ABC test

This study aimed to examine the probable developmental coordination disorder (DCD) and to identify differences in motor performance according to handedness, sex and age in typically developing Portuguese children not engaged in out-of-school sports. The Movement Assessment Battery for Children (M-ABC) was applied to a convenience sample of 154 right-handed and 119 left-handed children (n = 273), aged 4–12 (mean age = 7.96 years, SD = 2.38). The results suggest that the occurrence rate of probable DCD was 25.3% for right-handers and 36.1% for left-handers. This study showed a significant effect of handedness in age band 2, left-handers exhibited a higher prevalence of probable DCD than right-handers. Sex produced a significant effect, with girls performing better in manual dexterity in age band 1 and boys performing better in ball skills in age bands 2 and 3. The lower motor performances were observed in older children. These findings reinforce for Portuguese children and particularly for left-handers, the need for further investigation involving longitudinal studies and children of different handedness in the motor coordination domain. Moreover, we highlight the importance of developing physical education programmes that emphasize motor coordination parameters, especially in left-handed children.

Low motor performance scores among overweight children: Poor coordination or morphological constraints?

This study examined whether lower motor performance scores can be full attributed to poor coordination, or whether weight related morphological constraints may also affect motor performance. Data for 666 children and adolescents from the longitudinal Western Australian Pregnancy Cohort (Raine) Study were grouped into normal weight, overweight and obese categories based on the International Obesity Task Force cut points. Participants completed the 10-item McCarron Assessment of Neuromuscular Development (MAND) at the 10 and 14year follow-up. The prevalence of overweight and obese participants classified with mild or moderate motor difficulties was not different from the normal weight group at 10years (χ2=5.8 p=.215), but higher at 14years (χ2=11.3 p=.023). There were no significant differences in overall motor performance scores between weight status groups at 10years, but at 14years, the normal weight group achieved better scores than the obese group (p<.05). For specific items, the normal weight group consistently scored higher than the overweight and obese groups on the jump task at 10 (p<.001) and 14 (p<.01)years but lower on the hand strength task at both ages (p<.01). Our findings raise the question as to whether some test items commonly used for assessing motor competence are appropriate for an increasingly overweight and obese population.

Specific Deficit Analyses in Motor Performance and Quality of Life of Pediatric Cancer Patients—A Cross-Sectional Pilot Study

Although survival rates in childhood cancer have distinctly improved, pediatric cancer patients often experience various disease- and treatment-related side effects with long-term consequences. Despite current studies investigating inactivity and limitations in physical functioning and quality of life in pediatric cancer patients, only little information regarding specific deficits in physical functioning and quality of life has been available until now. No study has yet analyzed these parameters from a global perspective and then identified specific deficits in a mixed childhood cancer population. Within this cross-sectional pilot study, motor performance and quality of life of 26 pediatric cancer patients were assessed after inpatient medical treatment, using standardized motor test batteries (MOT 4–6; DMT 6–18) and a quality of life questionnaire (KINDL®). Reference data have been mainly provided by the German “Children and Young People Health Survey” (KiGGS). Patients achieved lower motor performance scores (p = .000) (more than 27% below the average of healthy peers). Specific deficits were identified in motor speed and motor control (4–6 years), as well as in endurance, strength and coordination under time pressure (6–17 years). In terms of quality of life, no significant differences were examined compared to healthy children of the same age. The results of this study confirm that children with oncological diseases frequently have specific motor problems. Future research in pediatric oncology must investigate the impact of targeted, individualized exercise interventions addressing these specific deficits.

Molecular, Physiological, and Motor Performance Defects in DMSXL Mice Carrying &gt;1,000 CTG Repeats from the Human DM1 Locus

Myotonic dystrophy type 1 (DM1) is caused by an unstable CTG repeat expansion in the 3′UTR of the DM protein kinase (DMPK) gene. DMPK transcripts carrying CUG expansions form nuclear foci and affect splicing regulation of various RNA transcripts. Furthermore, bidirectional transcription over the DMPK gene and non-conventional RNA translation of repeated transcripts have been described in DM1. It is clear now that this disease may involve multiple pathogenic pathways including changes in gene expression, RNA stability and splicing regulation, protein translation, and micro–RNA metabolism. We previously generated transgenic mice with 45-kb of the DM1 locus and >300 CTG repeats (DM300 mice). After successive breeding and a high level of CTG repeat instability, we obtained transgenic mice carrying >1,000 CTG (DMSXL mice). Here we described for the first time the expression pattern of the DMPK sense transcripts in DMSXL and human tissues. Interestingly, we also demonstrate that DMPK antisense transcripts are expressed in various DMSXL and human tissues, and that both sense and antisense transcripts accumulate in independent nuclear foci that do not co-localize together. Molecular features of DM1-associated RNA toxicity in DMSXL mice (such as foci accumulation and mild missplicing), were associated with high mortality, growth retardation, and muscle defects (abnormal histopathology, reduced muscle strength, and lower motor performances). We have found that lower levels of IGFBP-3 may contribute to DMSXL growth retardation, while increased proteasome activity may affect muscle function. These data demonstrate that the human DM1 locus carrying very large expansions induced a variety of molecular and physiological defects in transgenic mice, reflecting DM1 to a certain extent. As a result, DMSXL mice provide an animal tool to decipher various aspects of the disease mechanisms. In addition, these mice can be used to test the preclinical impact of systemic therapeutic strategies on molecular and physiological phenotypes.

Muscle-Bone Characteristics in Children with Prader-Willi Syndrome

A decrease in muscle mass, low motor performance, and normal lumbar spine bone mineral density (BMD) have been reported in children with Prader-Willi syndrome (PWS). However, these data are limited by the fact that PWS children (who have short stature) were compared to age-matched healthy or obese individuals of normal height. The goal of the present study was to compare bone and muscle characteristics in PWS children to sex- and age- or height-matched healthy subjects. The study population included 17 PWS children (ages 6.2 to 17.5 yr; nine girls) who were not treated with GH. The axial skeleton was analyzed at the lumbar spine using dual-energy x-ray absorptiometry, and the appendicular skeleton (radius and tibia) was evaluated using peripheral quantitative computed tomography. Muscle parameters (mass, size, and functional parameters) were measured by dual-energy x-ray absorptiometry, peripheral quantitative computed tomography, and jumping mechanography, respectively. Compared to height-matched controls, PWS patients had normal axial and appendicular BMD, as well as normal muscle size. Compared to age- or height-matched controls of normal weight, PWS patients had lower maximal muscle force and power relative to body mass during jumping. PWS patients had similar absolute maximal muscle force but lower absolute maximal power compared to age- or height-matched controls. Relationships between bone mass and muscle size and force were similar in PWS patients and in healthy subjects. Relative to their height, PWS patients not treated with GH had normal axial and appendicular BMD, muscle size, and muscle-bone relationships.

A diet deficient in vitamin D 3 delays disease onset in the female, but not the male, G93A mouse model of amyotrophic lateral sclerosis

Background Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by muscle weakness, paralysis and death. Prenatal vitamin D3 (D3) deficiency delays disease onset and decreases disease severity in a mouse model of multiple sclerosis, a disease which shares common pathophysiologies with ALS. Objective To determine whether a diet deficient in D3 affects disease severity, functional outcomes and lifespan in a mouse model of ALS. Methods At age 25 d, 51 G93A mice (28 M, 23 F) were divided into two D3 groups: 1) adequate (AI; 1 IU D3/g feed) and 2) deficient (DEF; 0.025 IU D3/g feed). Starting at age 60 d, functional and disease outcomes were measured until endpoint (CS 5). Tibialis anterior (TA), quadriceps and brain were harvested at age 113 d from an additional 35 G93A mice. Results No differences were found in disease severity and lifespan between DEF and AI mice, however DEF-F tended to have 22% lower motor performance (MP) area under the curve vs. AI-F between disease onset (CS 2) and CS 5 (P = 0.100). DEF-F reached CS 2 at a 48% slower rate than AI-F (HR = 0.52, 95% CI: 0.20, 0.89; P = 0.023), a delay of 5 d (P = 0.060). Body weight-adjusted TA (r = 0.65, P < 0.001) and quadriceps (r = 0.66, P < 0.001) weights strongly correlated with age at CS 2. Conclusion D3 deficiency in female G93A mice delays disease onset, but compromises MP between disease onset and endpoint. Supported by NSERC and Faculty of Health-York U. Grant Funding Source: NSERC and Faculty of Health-York University