Muscle Weakness Research Articles

Secondary Adrenal Insufficiency : A Case Report

Introduction: Insufficient pituitary hormone output is referred to as hypopituitarism. Individuals experiencing lethargy, dizziness, orthostatic hypotension, hypoglycemia, nausea, vomiting, or generalized abdominal pain may be diagnosed with acute adrenocorticotropic hormone (ACTH) insufficiency. This report detailed a unique instance of hypopituitarism in a patient who complained of nausea, vomiting, hypotension, hypoglycemia, and overall abdominal pain and soreness. Case presentation: A 65-year-old male presented to the outpatient department with complaints of a cough of 1-day duration on August 9/03/21 associated with 4 to 5 episodes of vomiting and pain in the abdomen, in addition to that whole body darkening, fatigue, and appetite loss of 6 months. weight loss intermittent sweating, and eyebrow and axillary hair loss. SOB with mild activity and also bilateral breast pain but no mass. Discussion: The diagnosis of hypothyroidism and inexplicable fatigue made us believe that there was an adrenal deficiency, which might be treated with cortisol around eight o’clock. Even though the patient with a high stress level the cortisol was immeasurable; so the diagnosis, of adrenal insufficiency, could be made. Other tests including ACTH and Imaging are usually needed to discover the subtype of insufficiency. The follow-up after 1 month showed no signs or symptoms left and a much better condition. Conclusion: When treating individuals who have fatigue that cannot be attributed to anything else, especially when weight loss and muscle weakness are present, adrenal insufficiency should be taken into consideration. A secondary adrenal insufficiency may exist even in the absence of skin pigmentation, which frequently triggers anxieties and ideas about Addison’s disease. If it is not identified promptly, it may potentially result in an adrenal crisis in situations with high-stress levels. Our patient presented with vague and largely mild symptoms related to early secondary adrenal insufficiency. These included nausea and vomiting, as well as fatigue. Laboratory studies indicated new hyponatremia and urine studies showed inappropriately normal urine sodium and osmolality. His morning serum cortisol was low, with borderline low ACTH, consistent with a secondary cause.

The thin fat paradox: Understanding normal weight obesity and its clinical relevance

Obesity, defined by the World Health Organization (WHO) as an excess accumulation of body fat or body fat percentage (BFP) associated with clear health risks, presents a significant global challenge. While Body Mass Index (BMI) serves as a conventional metric for identifying obesity, it fails to account for body composition variations, such as distinguishing between fat-free mass and adipose tissue. Consequently, individuals with normal BMI may exhibit excessive body fat (BFP≥30%), termed Normal Weight Obesity (NWO). In contrast, others with normal BMI and normal body fat are termed Normal Weight Lean (NWL). NWO significantly elevates the risks of various metabolic disorders, including hyperglycemia, diabetes, hypertension, dyslipidemia, and reduced HDL levels. Moreover, NWO is associated with an increased risk of cardiovascular diseases (CVD), hypertension, low HDL, central obesity, and muscle weakness. Individuals with NWO face a heightened risk of developing cardiometabolic diseases, including atherosclerosis, coronary artery disease, stroke, and heart failure, due to the adverse effects of excess body fat on cardiovascular health. Furthermore, NWO is associated with insulin resistance, inflammation, and endothelial dysfunction, further exacerbating the risk of metabolic disorders and cardiovascular complications. Early identification of NWO is crucial for implementing preventive measures and lifestyle interventions to mitigate these health risks. Integrating body fat percentage measurements into nutritional screening protocols in healthcare facilities is essential for identifying individuals at risk of NWO and initiating appropriate interventions to prevent the onset of cardiometabolic diseases. This study aims to provide comprehensive insights into Normal-Weight Obesity (NWO) and its potential health implications.

Assessing quadriceps strength in patellofemoral pain patients: A study on the reliability and validity of a low-cost strain-gauge for clinical practice.

Patellofemoral pain (PFP) is a common knee complaint affecting diverse populations both acutely and chronically. Quadriceps muscle weakness is one possible aetiology, but current devices for measuring muscle strength (isokinetic dynamometer [ID] and hand-held dynamometers [HHD]) are frequently too expensive (e.g., ID) or lack reliability (e.g., HHD) for practitioners, especially in under-resourced settings. There is a need to evaluate a low-cost device to manage rehabilitation of people with PFP. Isometric quadriceps strength of participants aged 18-35 years (total [n = 33], control group [n = 17] and PFP group [n = 16]) were evaluated on an isokinetic dynamometer and a commercially available strain gauge at baseline and after an 8-week non-standardised intervention. The strain gauge showed high absolute and relative reliability (intraclass correlation coefficient = 0.89-0.99; typical error of measurement = 3.9-10.4%). Clinically meaningful difference scores (12.2-45 Nm) were greater than the typical error of measurement, implying sufficient sensitivity of the strain gauge to measure true changes in isometric quadricep strength. Strong to very strong correlations were evident between the strain gauge and isokinetic dynamometer torque measurements (r = 0.88-0.90, SEE = 0.05-0.07 Nm), but slope values (β = 0.65-0.77) indicated that torque from the strain gauge was lower than that obtained from the isokinetic dynamometer. An average systematic bias of 16.3-28.8 Nm was evident in favour of the isokinetic dynamometer, with no statistically significant between-group differences apparent between baseline and follow-up testing. The present commercially available strain gauge is reliable and sensitive enough to detect clinically meaningful differences in quadriceps strength of both healthy individuals and those with PFP. However, the strain gauge lacks validity and therefore cannot replace isokinetic dynamometry. Given the low cost and excellent reliability, the strain gauge can be a valuable tool to assess quadriceps muscle deficits and track rehabilitation progress in people with PFP.

Chronological and Biological Aging in Amyotrophic Lateral Sclerosis and the Potential of Senolytic Therapies

Amyotrophic Lateral Sclerosis (ALS) is a group of sporadic and genetic neurodegenerative disorders that result in losses of upper and lower motor neurons. Treatment of ALS is limited, and survival is 2–5 years after disease onset. While ALS can occur in younger individuals, the risk significantly increases with advancing age. Notably, both sporadic and genetic forms of ALS share pathophysiological features overlapping hallmarks of aging including genome instability/DNA damage, mitochondrial dysfunction, inflammation, proteostasis, and cellular senescence. This review explores chronological and biological aging in the context of ALS onset and progression. Age-related muscle weakness and motor unit loss mirror aspects of ALS pathology and coincide with peak ALS incidence, suggesting a potential link between aging and disease development. Hallmarks of biological aging, including DNA damage, mitochondrial dysfunction, and cellular senescence, are implicated in both aging and ALS, offering insights into shared mechanisms underlying disease pathogenesis. Furthermore, senescence-associated secretory phenotype and senolytic treatments emerge as promising avenues for ALS intervention, with the potential to mitigate neuroinflammation and modify disease progression.

Multidisciplinary approach on divergent outcomes in spinal muscular atrophies: comparing DYNC1H1 and SMN1 gene mutations.

Spinal Muscular Atrophy (SMA) emerges as a prominent genetic neuromuscular disorder primarily caused by variants in the survival motor neuron (SMN) gene. However, it is noteworthy that alternative variants impacting DYNC1H1 have also been linked to a subtype known as spinal muscular atrophy lower extremity predominant (SMA-LED). This observation underscores the complexity of SMA and highlights the necessity for tailored, gene-specific management strategies. Our study elucidates how similar approaches to managing SMA can yield distinct outcomes, emphasizing the imperative for personalized gene-based interventions in effectively addressing these conditions.Two patients were referred for further management due to clinical suspicion of type-3 SMA. The definitive diagnosis was confirmed through the polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) technique, as well as whole-exome sequencing (WES).The analysis revealed deletions in exon-7 and 8 of SMN1 in the first patient and a likely pathogenic mutation (NM_001376.5(DYNC1H1):c.1867T > C (NP_001367.2: p.Phe623Leu)) in DYNC1H1 in the second patient. Both patients presented with lower limb muscle weakness. However, while the first patient exhibited a gradual increase in severity over the years, the second patient displayed no progressive symptoms. The management was adjusted accordingly based on the genetic findings.Our observation underscores the complexity of SMA and highlights the necessity for tailored, gene-specific management strategies. Our study elucidates how similar approaches to managing SMA can yield distinct outcomes, emphasizing the imperative for personalized gene-based interventions in effectively addressing these conditions.

Falls, fracture and frailty risk in multiple sclerosis: a Mendelian Randomization study to identify shared genetics.

Patients with multiple sclerosis (MS) commonly present musculoskeletal disorders characterized by lower bone mineral density (BMD) and muscle weakness. However, the underlying etiology remains unclear. Our objective is to identify shared pleiotropic genetic effects and estimate the causal relationship between MS and musculoskeletal disorders. We conducted linkage disequilibrium score regression (LDSR), colocalization, and Mendelian randomization (MR) analyses using summary statistics from recent large-scale genome-wide association studies (GWAS), encompassing MS, falls, fractures, and frailty. Additional MR analyses explored the causal relationship with musculoskeletal risk factors, such as BMD, lean mass, grip strength, and vitamin D. We observed a moderate genetic correlation between MS and falls (RG = 0.10, P-value = 0.01) but not between MS with fracture or frailty in the LDSR analyses. MR revealed MS had no causal association with fracture and frailty but a moderate association with falls (OR: 1.004, FDR q-value = 0.018). We further performed colocalization analyses using nine SNPs that exhibited significant associations with both MS and falls in MR. Two SNPs (rs7731626 on ANKRD55 and rs701006 on OS9 gene) showed higher posterior probability of colocalization (PP.H4 = 0.927), suggesting potential pleiotropic effects between MS and falls. The nine genes are associated with central nervous system development and inflammation signaling pathways. We found potential pleiotropic genetic effects between MS and falls. However, our analysis did not reveal a causal relationship between MS and increased risks of falls, fractures, or frailty. This suggests that the musculoskeletal disorders frequently reported in MS patients in clinical studies are more likely attributed to secondary factors associated with disease progression and treatment, rather than being directly caused by MS itself.

Balance function in critical illness survivors and evaluation of psychometric properties of the Mini-BESTest

Critical illness survivors commonly face impairments, such as intensive care unit-acquired weakness (ICUAW) which is characterized by muscle weakness and sensory deficits. Despite these symptoms indicating potential balance deficits, systematic investigations and validated assessments are lacking. Therefore, we aimed to assess balance function using the Mini-BESTest, evaluate its psychometric properties, and identify associated variables. Balance was assessed post-ICU discharge (V1) and at discharge from inpatient neurorehabilitation (V2) in patients with ≥ 5 days of invasive ventilation. Mini-BESTest measurement characteristics were evaluated in an ambulatory subgroup. A multiple linear regression was conducted. The prospective cohort study comprised 250 patients (34% female, 62 ± 14 years, median ICU stay 55 days). Median Mini-BESTest scores improved significantly from V1 (5 (IQR 0–15)) to V2 (18.5 (10–23)) with a large effect size. Excellent inter-rater and test–retest reliabilities of the Mini-BESTest were observed (ICC = 0.981/0.950). Validity was demonstrated by a very high correlation with the Berg Balance Scale (ρ = 0.90). No floor or ceiling effects were detected. Muscle strength, cognitive function, cerebral disease, critical illness polyneuropathy/myopathy, and depression were significantly associated with balance. Despite significant improvements during the rehabilitation period, balance disorders were prevalent in critical illness survivors. Ongoing therapy is recommended. Due to its excellent psychometric properties, the Mini-BESTest is suitable for use in critical illness survivors.Registration: The study was registered at the German Clinical Trials Register (DRKS00021753, date of registration: 2020-09-03).

Neurologic recovery following laminectomy and tumor resection of a pediatric cervical synovial osteochondromatosis causing paralysis.

To report the surgical outcome of synovial osteochondromatosis, a rare tumor of the cervical spine, in a 6-year-old boy. A 6-year-old boy presented with muscle weakness in the right deltoid (2) and biceps (4) during a manual muscle test. Magnetic resonance imaging showed a 3 × 2 × 1.5cm mass within the spinal canal at the C4-6 level, compressing the cervical spinal cord from the right side. Computed tomography revealed hyperintense areas within the tumor and ballooning of the right C4-5 and C5-6 facet joints. After a biopsy confirmed the absence of malignancy, a gross total resection was performed. The pathological diagnosis of synovial osteochondromatosis was established. Postoperatively, muscle weakness improved fully in the manual muscle test, and there were no neurological findings after 3months. However, the patient is under careful follow-up owing to the detection of a regrowth site within the right C4-5 and C5-6 intervertebral foramen 2years postoperatively. Synovial osteochondromatosis of the cervical spine in children is rare, and this is the first report of its regrowth after surgery. Synovial osteochondromatosis should be included in the differential diagnosis of pediatric cervical spine tumors.

A rheumatological catastrophe: case of amyopathic juvenile dermatomyositis

Juvenile-onset amyopathic dermatomyositis is rare variant of juvenile-onset dermatomyositis (JDM), characterized by the hallmark cutaneous features of dermatomyositis without clinical or laboratory evidence of muscle disease. Dermatomyositis with positive anti-melanoma differentiation-associated gene 5 (anti-MDA5) antibody has a distinct phenotype associated with small hand joint arthritis, mucocutaneous ulceration in the absence of muscle involvement. In this article, we describe a 5-year-old child presented with mucocutaneous manifestations with no muscle weakness who responded to immunosuppressive therapy.

How Could We Prevent the Threatening of Falls to the Elderly?

Falls among the elderly population can have serious and potentially life-threatening consequences. To prevent such incidents, a multi-faceted approach must be implemented within the healthcare system. Firstly, healthcare providers should conduct routine screenings for fall risk factors, such as muscle weakness and balance issues, during regular check-ups. Additionally, implementing regular exercise programs that focus on improving strength and balance can help reduce the likelihood of falls. Assessing and modifying the home environment to remove potential hazards, such as uneven flooring or inadequate lighting, is also crucial in preventing falls. Furthermore, educating both the elderly individuals and their caregivers about fall prevention strategies is essential. By combining these efforts with proper medication management and regular vision checks, we can effectively decrease the threat of falls among the elderly population and improve their overall quality of life.

Challenging diagnosis of a rare disease: hypophosphatemic osteomalacia – case report and literature review

Hypophosphatemic osteomalacia is a rare condition caused by different causes, all resulting in disturbances of calcium-phosphate management. One of the most common causes among adults is tumor-induced osteomalacia, which is characterized by increased secretion of fibroblast growth factor-23. Its symptoms are vague, tests necessary for diagnosis are not commonly used by clinicians and some of them are only available in highly specialized centers. Due to these reasons, patients often are misdiagnosed for more common conditions and are left without proper treatment for many years. We present a case of a patient suffering from multiple fractures, diffuse bone pain, and muscle weakness, who was previously misdiagnosed for osteoporosis, primary and secondary hyperparathyroidism. We discuss the pathophysiology of tumor-induced osteomalacia, diagnostic path, differential diagnosis, available forms of treatment and possible complications.

Anti-HMGCR (Hydroxy-3-Methylglutaryl-CoA Reductase) Myopathy: A Rare Cause of Proximal Muscle Weakness

Anti-HMGCR (Hydroxy-3-Methylglutaryl-CoA Reductase) Myopathy: A Rare Cause of Proximal Muscle Weakness

Effects of Manual Therapy in Management of Diastasis Recti - A Case Study

ABSTRACT: Background: The patient was a 32 years old postpartum female with complaint of back pain which was radiating to abdominal area, she was functional limitations and abdominal muscle weakness. Methods and Measures: patient was treated 8 sessions over a period of 4 weeks. Study: Case study Intervention: Intervention included KT for rectus abdominis muscle and PF strengthening exercises to stabilize and strengthen the weakened muscles and to reduce IRD. Results: Following treatment, the patient demonstrated in an increase in functional ability and resolution of functional limitations. Statistical analysis of the data showed significant differences from pre to post intervention from session 1 to session 8. There was clinical and statistical significance found in PFS and IRD. Conclusion: Findings suggest that KT and PF strengthening exercises are more effective in reducing IRD and improving function in patient with Diastasis Recti Key words: Inter-Recti Distance(IRD), Rectus Abdominis (RA), Rectus Diastasis (RD), Diastasis Recti Abdominis(DRA), Ultrasound (Usd), Kinesio taping (KT), Physical Function Scale (PFS),Pelvic Floor (PF), Rate of Perceived Exertion (RPE), Linea Alba (LA).

Inflammatory Cytokine-Induced Muscle Atrophy and Weakness Can Be Ameliorated by an Inhibition of TGF-β-Activated Kinase-1

Chronic inflammation causes muscle wasting. Because most inflammatory cytokine signals are mediated via TGF-β-activated kinase-1 (TAK1) activation, inflammatory cytokine-induced muscle wasting may be ameliorated by the inhibition of TAK1 activity. The present study was undertaken to clarify whether TAK1 inhibition can ameliorate inflammation-induced muscle wasting. SKG/Jcl mice as an autoimmune arthritis animal model were treated with a small amount of mannan as an adjuvant to enhance the production of TNF-α and IL-1β. The increase in these inflammatory cytokines caused a reduction in muscle mass and strength along with an induction of arthritis in SKG/Jcl mice. Those changes in muscle fibers were mediated via the phosphorylation of TAK1, which activated the downstream signaling cascade via NF-κB, p38 MAPK, and ERK pathways, resulting in an increase in myostatin expression. Myostatin then reduced the expression of muscle proteins not only via a reduction in MyoD1 expression but also via an enhancement of Atrogin-1 and Murf1 expression. TAK1 inhibitor, LL-Z1640-2, prevented all the cytokine-induced changes in muscle wasting. Thus, TAK1 inhibition can be a new therapeutic target of not only joint destruction but also muscle wasting induced by inflammatory cytokines.

P.041 3 year longitudinal health related quality of life in a spinal muscular atrophy cohort

Background: Spinal Muscular Atrophy (SMA) is a rare, genetic disorder marked by motor neuron degeneration, causing progressive muscle weakness. SMA significantly impacts patients and their families. This study investigates HRQOL in a longitudinal SMA cohort. Methods: The study used the Canadian Neuromuscular Disease Registry to examine HRQOL in children aged 6-10 years with genetically confirmed SMA. HRQOL was evaluated using the PedsQL™ Measurement Model. This tool is validated in children and adolescents with various health conditions. The PedsQL Neuromuscular Module which has been validated in SMA was also used. Results: Eight participants completed the PedsQL generic and Neuromuscular Module at timepoint 1 (TP1) and 2 (TP2). The mean scores at TP1 were 49.66 (SD=5.05) for the generic PedsQL and 61.06 (SD=18.37) for the Neuromuscular Module. At TP2, mean scores increased to 59.32 (SD=13.08) and 74.86 (SD=9.88), respectively. The overall mean change over the two timepoints was +9.66 (SD=15.16) for the Generic PedQL and +13.80 (SD=23.03) for the Neuromuscular Module. Six participants were on disease modifying treatment. Conclusions: HRQOL scores in SMA patients improved over the study period. The enhancement in HRQOL may indicate the positive impact of diseases modifying treatments of SMA that became available during that time.

P.042 Anti-HMG Coenzyme A reductase antibody (anti-HMGCR) myopathy: case review of two pediatric patients from a single center

Background: Necrotizing anti-HMGCR myopathy is rare in children. Pediatric cases are not typically associated with statin use or malignancy. Methods: Retrospective chart review (January 2009 to December 2023) identified cases of anti-HMGCR myopathy at our hospital. Results: Two patients were identified. Patient A, presented at 8 yo with a 2 year history of proximal muscle weakness. His CK was 4,840 U/L (normal <205 U/L) with a high anti-HMGCR antibody titre. His Childhood Myositis Assessment Scale (CMAS) score was 33/52. Monthly IVIG was started and his muscle strength and CK improved. Two years later, weekly methotrexate was started for persistent mild CK elevation (602 to 869 U/L). At 11 years old, 3 years after diagnosis, his CMAS score was 47 and he could participate in soccer with mild fatigue. Patient B, presented at 8 yo with acute proximal weakness, rash and CMAS 13/52. His CK was 20,185 U/L with elevated anti-HMGCR antibody titre. He received oral corticosteroids, weekly methotrexate and monthly IVIG. At 10 yo, 2 years after diagnosis, he is asymptomatic with CMAS 51. He is maintained on methotrexate monotherapy. Conclusions: Anti-HMGCR antibody myopathy requires prompt diagnosis to obviate muscle necrosis and long-term complications. Our patients showed clinical and CMAS improvement with treatment.

Treating myasthenia gravis beyond the eye clinic.

Myasthenia gravis (MG) is one of the most well characterised autoimmune disorders affecting the neuromuscular junction with autoantibodies targeting the acetylcholine receptor (AChR) complex. The vast majority of patients present with ocular symptoms including double vision and ptosis, but may progress on to develop generalised fatiguable muscle weakness. Severe involvement of the bulbar muscles can lead to dysphagia, dysarthria and breathing difficulties which can progress to myasthenic crisis needing ventilatory support. Given the predominant ocular onset of the disease, it is important that ophthalmologists are aware of the differential diagnosis, investigations and management including evolving therapies. When the disease remains localised to the extraocular muscles (ocular MG) IgG1 and IgG3 antibodies against the AChR (including clustered AChR) are present in nearly 50% of patients. In generalised MG this is seen in nearly 90% patients. Other antibodies include those against muscle specific tyrosine kinase (MuSK) and lipoprotein receptor related protein 4 (LRP4). Even though decremental response on repetitive nerve stimulation is the most well recognised neurophysiological abnormality, single fibre electromyogram (SFEMG) in experienced hands is the most sensitive test which helps in the diagnosis. Initial treatment should be using cholinesterase inhibitors and then proceeding to immunosuppression using corticosteroids and steroid sparing drugs. Patients requiring bulbar muscle support may need rescue therapies including plasma exchange and intravenous immunoglobulin (IVIg). Newer therapeutic targets include those against the B lymphocytes, complement system, neonatal Fc receptors (FcRn) and various other elements of the immune system.

#2814 Characterization of cardiological manifestations in patients with sodium-wasting tubulopathies

Abstract Background and Aims Bartter (BS) and Gitelman (GS) syndromes are rare tubulopathies caused by mutations affecting renal NaCl transporters, resulting in similar symptoms like muscle weakness, cramps, and electrolyte imbalances, with GS also presenting with hypomagnesemia. Treatment focuses on electrolyte and fluid balance, using supplements and drugs to inhibit prostaglandin production and RAAS activation. Electrolyte deficits in these conditions can extend the QT interval and increase the risk of potentially fatal cardiac arrhythmias. This study aims to profile BS and GS patients followed at our hospital, focusing on cardiological phenotyping. We assessed diagnostic, clinical, and lab data, particularly examining the link between electrolyte imbalances (like hypokalemia or hypomagnesemia) and electrocardiographic changes or cardiac symptoms during follow-up. Method We screened all BS and GS patients for study inclusion, requiring a genetic diagnosis with disease-causing mutations and comprehensive clinical and electrocardiographic data. We excluded cases lacking sufficient data. We gathered demographic and health information retrospectively, categorizing patients based on electrocardiographic results into groups: 1) persistent long QT interval, 2) transient long QT interval, and 3) no long QT interval. Data were summarized with medians, interquartile ranges, and frequencies. Results A total of 27 patients were enrolled in the study, 16 with Bartter Syndrome (BS) and 11 with Gitelman Syndrome (GS); median length of follow-up was 6 years (range 3-19). Only one patient was classified in group 1, with a constant QTc prolongation (446.3 ms); 8 patients (34.8%) fell into group 2 with median QTc values of 420 ms, all exhibiting hypokalemia and hypomagnesemia. The majority (14/23, 61%) were in group 3, with a median QTc of 399.2 ms and 79% displaying hypokalemia and hypomagnesemia. All 9 patients who experienced cardiac-related symptoms were adults, with 8 presenting these symptoms during intercurrent episodes. The study also compared clinical differences between BS and GS patients, noting a higher frequency of hypokalemia and hypomagnesemia in GS, whereas BS patients had more electrocardiographic alterations, although not statistically significant. No echocardiographic abnormalities were detected from the available data, and there were no recorded incidents of malignant arrhythmias or sudden death. Conclusion Electrocardiographic abnormalities in BS and GS patients fluctuate, often related to episodic events, with QT prolongation in one-third of cases but no severe cardiac complications, indicating a generally positive prognosis.

#2786 Effect of intradialytic virtual reality exercise program on lower limb muscle strength in patients on hemodialysis

Abstract Background and Aims In patients on hemodialysis, muscle weakness is highly prevalent and may lead to frailty, limitation of mobility and functional impairment. Moreover, low muscle strength was associated with an increase in mortality risk in these patients. Despite the fact that some studies showed that resistance training improves muscle strength in patients on hemodialysis, the effects of virtual reality (VR) exercise should be confirmed. Therefore, the aim of this study was to evaluate the effects of an intradialytic non-immersive VR exercise program, performed at different times during the hemodialysis session, on lower limb muscle strength in patients on hemodialysis. Method A randomized clinical trial was conducted with patients aged ≥18 years who were undergoing hemodialysis treatment for at least 3 months. Patients were randomized into 2 protocols of exercise at different times during the hemodialysis session (first 2 hours and last two hours) for 3 months. The intradialytic exercise program in both groups consisted of a non-immersive VR game (Treasure Hunting) in which the patients try to catch treasures and avoid bombs by moving their lower limbs (hip flexion, abduction and adduction, and knee flexion and extension), with a progressive duration of 6 to 36 minutes. The difficulty level of the game was graduated according to the characteristics of each patient. The muscle strength of the hip flexion (HF), hip abduction (HA) and ankle extension (AE) was evaluated using a portable handheld dynamometer during hemodialysis session. Patients were advised to perform a 5 s maximum isometric contraction, and the peak values were recorded for 3 repetitions in both lower limbs. The mean muscle strength of 3 trials was recorded. Data were expressed as the median (interquartile range). The Mann‒Whitney U test was used for between-group comparisons. The Friedman test was conducted to evaluate the differences in medians among the muscle strength data at baseline, after 1, 2 and 3 months of exercise program. Results This study included 11 patients in the exercise within the first 2 hours group [50 (55-75) years, 55% male] and 11 patients in the exercise within the last 2 hours group [64 (58-72) years, 64% male]. Table 1 shows that muscle strength of the HA and AE increased significantly in the exercise within the first 2 hours group. Muscle strength of HF, HA and AE improved significantly in the exercise within the last 2 hours group. There were no significant differences between two groups. Conclusion This study suggests that an intradialytic non-immersive VR exercise program can improve lower limb muscle strength in patients on hemodialysis.

Minimization of metabolic cost of transport predicts changes in gait mechanics over a range of ankle-foot orthosis stiffnesses in individuals with bilateral plantar flexor weakness

Neuromuscular disorders often lead to ankle plantar flexor muscle weakness, which impairs ankle push-off power and forward propulsion during gait. To improve walking speed and reduce metabolic cost of transport (mCoT), patients with plantar flexor weakness are provided dorsal-leaf spring ankle-foot orthoses (AFOs). It is widely believed that mCoT during gait depends on the AFO stiffness and an optimal AFO stiffness that minimizes mCoT exists. The biomechanics behind why and how an optimal stiffness exists and benefits individuals with plantar flexor weakness are not well understood. We hypothesized that the AFO would reduce the required support moment and, hence, metabolic cost contributions of the ankle plantar flexor and knee extensor muscles during stance, and reduce hip flexor metabolic cost to initiate swing. To test these hypotheses, we generated neuromusculoskeletal simulations to represent gait of an individual with bilateral plantar flexor weakness wearing an AFO with varying stiffness. Predictions were based on the objective of minimizing mCoT, loading rates at impact and head accelerations at each stiffness level, and the motor patterns were determined via dynamic optimization. The predictive gait simulation results were compared to experimental data from subjects with bilateral plantar flexor weakness walking with varying AFO stiffness. Our simulations demonstrated that reductions in mCoT with increasing stiffness were attributed to reductions in quadriceps metabolic cost during midstance. Increases in mCoT above optimum stiffness were attributed to the increasing metabolic cost of both hip flexor and hamstrings muscles. The insights gained from our predictive gait simulations could inform clinicians on the prescription of personalized AFOs. With further model individualization, simulations based on mCoT minimization may sufficiently predict adaptations to an AFO in individuals with plantar flexor weakness.