Predictors of low and very low bone mineral density in long-term childhood acute lymphoblastic leukemia survivors: Toward personalized risk prediction.

BACKGROUND: Cohorts of childhood acute lymphoblastic leukemia (cALL) survivors reaching adulthood are increasing. Approximately 30% of survivors meet criteria for low bone mineral density (BMD) 10 years after diagnosis. We investigated risk factors for low BMD in long-term cALL survivors. METHODS: We recruited 245 cALL survivors from the PETALE (Prévenir les effets tardifs des traitements de la leucémie aiguë lymphoblastique chez l'enfant) cohort, who were treated with the Dana Farber Cancer Institute protocols, did not experience disease relapse or hematopoietic stem cell transplants, and presented with more than 5 years of event-free survival. Median time since diagnosis was 15.1 years. RESULTS: Prevalence of low DXA-derived BMD (Z-score ≤-1) ranged between 21.9% and 25.3%, depending on site (lumbar spine (LS-BMD), femoral neck (FN-BMD), and total body (TB-BMD), and between 3.7% and 5.8% for very low BMD (Z-score ≤-2). Males had a higher prevalence of low BMD than females for all three outcomes (26%-32% vs. 18%-21%), and male sex acted as a significant risk factor for low BMD in all models. Treatment-related factors such as cumulative glucocorticoid (GC) doses and cranial radiation therapy (CRT) were associated with lower BMDs in the full cohort and in females at the FN-BMD site. CONCLUSION: Low and very low BMD is more prevalent in male cALL survivors. Male sex, high cumulative GC doses, CRT, risk group, and low body mass index (BMI) were identified as risk factors for low BMD. A longer follow-up of BMD through time in these survivors is needed to establish if low BMD will translate into a higher risk for fragility fractures through adulthood.

Comparing a Portable Motion Analysis System against the Gold Standard for Potential Anterior Cruciate Ligament Injury Prevention and Screening.

Knee kinematics during a drop vertical jump, measured by the Kinect V2 (Microsoft, Redmond, WA, USA), have been shown to be associated with an increased risk of non-contact anterior cruciate ligament injury. The accuracy and reliability of the Microsoft Kinect V2 has yet to be assessed specifically for tracking the coronal and sagittal knee angles of the drop vertical jump. Eleven participants performed three drop vertical jumps that were recorded using both the Kinect V2 and a gold standard motion analysis system (Vicon, Los Angeles, CA, USA). The initial coronal, peak coronal, and peak sagittal angles of the left and right knees were measured by both systems simultaneously. Analysis of the data obtained by the Kinect V2 was performed by our software. The differences in the mean knee angles measured by the Kinect V2 and the Vicon system were non-significant for all parameters except for the peak sagittal angle of the right leg with a difference of 7.74 degrees and a p-value of 0.008. There was excellent agreement between the Kinect V2 and the Vicon system, with intraclass correlation coefficients consistently over 0.75 for all knee angles measured. Visual analysis revealed a moderate frame-to-frame variability for coronal angles measured by the Kinect V2. The Kinect V2 can be used to capture knee coronal and sagittal angles with sufficient accuracy during a drop vertical jump, suggesting that a Kinect-based portable motion analysis system is suitable to screen individuals for the risk of non-contact anterior cruciate ligament injury.

Tendon properties in a mouse model of severe osteogenesis imperfecta.

PURPOSE/AIM OF THE STUDY: Osteogenesis imperfecta is a heritable bone disorder that is usually caused by mutations in collagen type I encoding genes. The impact of such mutations on tendons, a structure with high collagen type I content, remains largely unexplored. We hypothesized that tendon properties are abnormal in the context of a mutation affecting collagen type I. The main purpose of the study was to assess the anatomical, mechanical, and material tendon properties of Col1a1Jrt/+ mice, a model of severe dominant OI. MATERIALS AND METHODS: The Flexor Digitorum Longus (FDL) tendon of Col1a1Jrt/+ mice and wild-type littermates (WT) was assessed with in vitro mechanical testing. RESULTS: The results showed that width and thickness of FDL tendons were about 40% larger in WT (p < 0.01) than in Col1a1Jrt/+ mice, whereas the cross-sectional area was 138% larger (p < 0.001). The stiffness, peak- and yield-force were between 160% and 194% higher in WT vs. Col1a1Jrt/+ mice. The material properties did not show significant differences between mouse strains with differences <15% between WT and Col1a1Jrt/+ (p > 0.05). Analysis of the Achilles tendon collagen showed no difference between mice strains for the content but collagen solubility in acetic acid was 66% higher in WT than in Col1a1Jrt/+ (p < 0.001). CONCLUSIONS: This study shows that the FDL tendon of Col1a1Jrt/+ mice has reduced mechanical properties but apparently normal material properties. It remains unclear whether the tendon phenotype of Col1a1Jrt/+ mice is secondary to muscle weakness or a direct effect of the Col1a1 mutation or a combination of both.

Measurement Repeatability and Reproducibility of Virtual Goniometry of a Set of Acquired Images in Youths with Arthrogryposis Multiplex Congenita.

OBJECTIVES: To evaluate the intra-rater repeatability and the inter-rater reproducibility of using a virtual goniometer to measure upper and lower extremity joint range of motion (ROM) in youths with arthrogryposis multiplex congenita (AMC). METHODS: Youths presenting with AMC aged 8 to 21 years old were recruited. ROM of the upper and lower limbs were assessed remotely during a teleassessment on a video-conferencing platform. Screen captures were taken and ROM were measured by two raters, two-weeks apart, using a virtual goniometer. Intraclass correlation coefficient (ICC) and associated 95% confidence interval (CI) were calculated to assess intra-and inter-rater repeatability and reproducibility. RESULTS: Nine participants were included with a median age of 15.9 years (range: 11.3 to 20.8 years). The overall intra-rater ICC was 0.997 (95% CI:0.996 to 0.997) for the first rater and 0.993 (95% CI:0.992 to 0.994) for the second rater. The inter-rater ICC ranged from 0.410 (95% CI:-0.392; 0.753) for forearm pronation to 0.998 (95% CI:0.996; 0.999) for elbow flexion. CONCLUSIONS: Results of the current study suggest that virtual goniometry is reproducible and repeatable for the ROM of most joints. Future studies should evaluate procedural reliability and validity of the proposed method for youth with complex conditions.

Muscle-bone properties after prolonged voluntary wheel running in a mouse model of dominant severe osteogenesis imperfecta.

OBJECTIVE: The objective of the current study is to assess the effect of a seven-week voluntary wheel running intervention on muscles and bones properties in a mouse model mimicking dominant severe osteogenesis imperfecta (OI). METHODS: Female wild-type (WT) and OI (Col1a1Jrt/+) mice either performed voluntarily wheel-running exercise for 7-weeks or remained sedentary. Running distance and speed, forelimb grip strength, isolated muscle force and fatigability as well as bone morphology and mechanical properties were assessed. RESULTS: We demonstrate that female WT and OI mice voluntarily performed exercise, although OI mice exercised less than WT littermates. The exercise regimen increased soleus muscle masses in WT and OI but increased relative grip strength in WT mice only. Specific muscle force and fatigability were similar between WT and OI mice and did not improve with exercise. Furthermore, the exercise regimen did not improve the femoral architectural and biomechanical properties in OI mice. CONCLUSION: Our study suggests that voluntary wheel running is not appropriate to assess the effects of exercise in a mouse model of OI. Findings from exercising OI mice model studies may not necessarily be transferable to humans.

Using Telerehabilitation to Deliver a Home Exercise Program to Youth With Arthrogryposis: Single Cohort Pilot Study.

BACKGROUND: Arthrogryposis multiplex congenita (AMC) is characterized by joint contractures and muscle weakness, which limit daily activities. Youths with AMC require frequent physical therapeutic follow-ups to limit the recurrence of contractures and maintain range of motion (ROM) and muscle strength; however, access to specialized care may be limited because of geographical distance. Telerehabilitation can offer a potential solution for delivering frequent follow-ups for youth with AMC, but research on the use of telerehabilitation in children with musculoskeletal disorders is scarce. OBJECTIVE: The study aims to evaluate the feasibility of delivering a home exercise program (HEP) by using telerehabilitation for youth with AMC. We also aim to explore the effectiveness of the HEP as a secondary aim. METHODS: Youths aged between 8 and 21 years with AMC were recruited at the Shriners Hospitals for Children-Canada. The participants completed baseline and post-HEP questionnaires (the Physical Activity Questionnaire for Adolescents, Pediatrics Outcomes Data Collection Instrument, and Adolescent and Pediatric Pain Tool), and clinicians assessed their active ROM using a virtual goniometer. Clinicians used the Goal Attainment Scale with the participants to identify individualized goals to develop a 12-week HEP and assess the achievement of these goals. Follow-ups were conducted every 3 weeks to adjust the HEP. Data on withdrawal rates and compliance to the HEP and follow-ups were collected to assess the feasibility of this approach. The interrater reliability of using a virtual goniometer was assessed using the intraclass correlation coefficient and associated 95% CI. Nonparametric tests were used to evaluate feasibility and explore the effectiveness of the HEP. RESULTS: Of the 11 youths who were recruited, 7 (median age: 16.9 years) completed the HEP. Of the 47 appointments scheduled, 5 had to be rescheduled in ≤24 hours. The participants performed their HEP 2.04 times per week (95% CI 1.25-4.08) and reported good satisfaction with the approach. A general intraclass correlation coefficient of 0.985 (95% CI 0.980-0.989) was found for the web-based ROM measurement. Individualized goals were related to pain management; endurance in writing, standing, or walking; sports; and daily activities. In total, 12 of the 15 goals set with the participants were achieved. Statistically significant improvements were observed in the pain and comfort domain of the Pediatrics Outcomes Data Collection Instrument (preintervention: median 71; 95% CI 34-100; postintervention: median 85; 95% CI 49-100; P=.08) and Physical Activity Questionnaire for Adolescents (preintervention: median 1.62; 95% CI 1.00-2.82; postintervention: median 2.32; 95% CI 1.00-3.45; P=.046). CONCLUSIONS: The remote delivery of an HEP for youth with AMC is feasible. Promising results were found for the effectiveness of the HEP in helping youths with AMC to achieve their goals. The next step will be to assess the effectiveness of this exercise intervention in a randomized controlled trial. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.2196/18688.

Clinical manifestations of osteogenesis imperfecta in adulthood: An integrative review of quantitative studies and case reports.

Osteogenesis imperfecta (OI) is a rare genetic disorder of the bones caused by a mutation in Type I collagen genes. As adults with OI are aging, medical concerns secondary to OI may arise. This integrative review sought to review, appraise, and synthesize the clinical manifestations faced by adults with OI. Four electronic bibliographic databases were searched. Published quantitative, qualitative, and mixed-methods studies, as well as case reports from 2000 to March 2019, addressing a clinical manifestation in adulthood, were reviewed. Eligible studies and case reports were subsequently appraised using the Mixed Methods Appraisal Tool and Case Report Checklist, respectively. Twenty quantitative studies and 88 case reports were included for review regardless of the varying methodological quality score. These studies collectively included 2,510 adults with different OI types. Several clinical manifestations were studied, and included: hearing loss, cardiac diseases, pregnancy complications, cerebrovascular manifestations, musculoskeletal manifestations, respiratory manifestations, vision impairment, and other clinical manifestations. Increased awareness may optimize prevention, treatment, and follow-up. Opportunities to enhance the methodological quality of research including better design and methodology, multisite collaborations, and larger and diverse sampling will optimize the generalizability and transferability of findings.

Muscle and joint function in children living with arthrogryposis multiplex congenita: A scoping review.

Arthrogryposis multiplex congenita (AMC) is characterized by congenital joint contractures present in two or more body areas. Lack of fetal movement is the underlying cause of AMC, which can lead to abnormal connective tissue surrounding the joint resulting in stiffness and muscle atrophy. Treatment aims at improving function and mobility through surgical and/or conservative interventions. A scoping review was conducted to explore the existing knowledge of the evaluation and treatment of muscle and joint function in children with AMC. Three search engines were included and identified 1,271 articles. Eighty-seven studies met the selection criteria and were included in this review. All included studies focused on joints, 30 of which also assessed the muscle. Assessment most often included the position of the contractures (n = 72), as well as range of motion (n = 66). Interventions to improve muscle and joint function were reported in 82 of the 87 papers and included surgery (n = 70) and conservative interventions (n = 74) with bony surgery (i.e., osteotomy) the most common surgery and rehabilitation the most common conservative intervention. Recurrences of contractures were mentioned in 46 of the 68 studies providing a follow-up. Future studies should use validated measures to assess muscle and joint function, and conservative interventions should be described in greater detail and to include a longer follow-up.

Incidence of knee height asymmetry in a paediatric population of corrected leg length discrepancy: a retrospective chart review study.

PURPOSE: The purpose of the study is to provide a methodology to quantify knee height asymmetry (KHA) and to establish the incidence of knee height asymmetry in a patient population visiting the limb length discrepancy clinic in a paediatric-orthopaedic hospital centre. METHOD: A retrospective chart review was performed on all patients who attended the limb length discrepancy clinic and underwent corrective surgery at the Shriners Hospital for Children-Canada from December 2009 to December 2015. Full-standing anteroposterior radiographs were used to measure pre- and post-surgery limb length discrepancy and knee height asymmetry for 52 individuals included in the study. RESULTS: Sixty-seven percent of the studied population had a KHA of 20 mm or less, 25% had a KHA between 20 and 40 mm, and 8% had a KHA of over 40 mm. The average KHA preoperatively for all 52 individuals was 17 ± 14 mm (range 0-59 mm), which represents roughly 2.5% of total limb length. There was a 3-mm non-significant reduction in KHA size between pre-and post-operative states (p = 0.22). CONCLUSION: The current study provides a method to quantify knee height asymmetry. Using this method, it was shown that knee height asymmetry is frequent in youth with limb length discrepancy in both pre- and post-corrective surgery states. The relatively high incidence of knee height asymmetry highlights the importance to investigate the impact of knee height asymmetry in youth living with a limb length discrepancy.

Muscle Function in Osteogenesis Imperfecta Type IV.

Results of previous studies suggest that children and adolescents with osteogenesis imperfecta (OI) type IV have muscle force deficits. However, muscle function remains to be objectively quantified in this population. This study aimed to assess upper and lower extremity muscle function in patients with OI type IV. It was carried out in the outpatient department of a pediatric orthopedic hospital; 27 individuals with OI type IV (7-21 years; 13 males), 27 age- and sex-matched individuals with OI type I, and 27 age- and sex-matched controls. Upper extremity muscle force was assessed with hydraulic hand dynamometry, and lower extremity muscle function (peak force per body weight and peak power per body mass) was measured by mechanography through five tests: multiple two-legged hopping, multiple one-legged hopping, single two-legged jump, chair-rise test, and heel-rise test. Upper-limb grip force was normal for patients with OI type IV when compared to height and sex reference data (average z-score = 0.17 ± 1.30; P = 0.88). Compared to age- and sex-matched controls, patients with OI type IV had approximately 30% lower-limb peak force and 50% peak power deficits (P values <0.05). At the lower-limb level, they had a 50% lower peak power than age- and sex-matched patients with OI type I (P < 0.05). Patients with OI type IV have normal upper-limb muscle force but a muscle function deficit at the lower-limb level. These results suggest that lower-limb muscle weakness may contribute to functional deficits in these individuals.

Muscle-Bone Interactions in Pediatric Bone Diseases.

PURPOSE: Here, we review the skeletal effects of pediatric muscle disorders as well as muscle impairment in pediatric bone disorders. RECENT FINDINGS: When starting in utero, muscle disorders can lead to congenital multiple contractures. Pediatric-onset muscle weakness such as cerebral palsy, Duchenne muscular dystrophy, spinal muscular atrophy, or spina bifida typically are associated with small diameter of long-bone shafts, low density of metaphyseal bone, and increased fracture incidence in the lower extremities, in particular, the distal femur. Primary bone diseases can affect muscles through generic mechanisms, such as decreased physical activity or in disease-specific ways. For example, the collagen defect underlying the bone fragility of osteogenesis imperfecta may also affect muscle force generation or transmission. Transforming growth factor beta released from bone in Camurati Engelman disease may decrease muscle function. FUTURE DIRECTIONS: Considering muscle-bone interactions does not only contribute to the understanding of musculoskeletal disorders but also can identify new targets for therapeutic interventions.

Static Postural Control in Youth With Osteogenesis Imperfecta Type I.

OBJECTIVES: To assess static postural control in eyes-open and eyes-closed conditions in individuals with osteogenesis imperfecta (OI) type I as compared with typically developing (TD) individuals and to explore the relation between postural control and lower limb muscle function. DESIGN: Cross-sectional study. SETTING: Outpatient department of a pediatric orthopedic hospital. PARTICIPANTS: A convenience sample (N=38) of individuals with OI type I (n=22; mean age, 13.1y; range, 6-21y) and TD individuals (n=16; mean age, 13.1y; range, 6-20y) was selected. Participants were eligible if they were between 6 and 21 years and if they did not have any fracture or surgery in the lower limb in the 12 months before testing. INTERVENTIONS: Not applicable. MAIN OUTCOMES MEASURES: Postural control was assessed through static balance tests and muscle function through mechanographic tests on a force platform. Selected postural parameters were path length, velocity, 90% confidence ellipse area, and the ellipse's length of the mediolateral and anteroposterior axes. Mechanographic parameters were peak force and peak power as measured using the multiple two-legged hopping and the single two-legged jump test, respectively. RESULTS: Individuals with OI type I had poorer postural control than did TD individuals as indicated by longer and faster displacements and a larger ellipse area. Muscle function was unrelated to postural control in the OI group. Removing visual information resulted in a larger increase in postural control parameters in the OI group than in the TD group. CONCLUSIONS: A proprioceptive deficit could explain poorer postural control in individuals with OI type I.

Delivering a Home-Based Exercise Program to Youth With Osteogenesis Imperfecta: Protocol for a Comparative-Approach Study.

BACKGROUND: Osteogenesis imperfecta (OI) is a rare bone fragility disorder associated with muscle weakness. Individuals with OI may therefore benefit from exercise interventions aiming to improve muscle and bone strength. Given the rarity of OI, many patients do not have access to exercise specialists who are familiar with the disorder. As such, telemedicine, the provision of health care through technology to provide care at a distance, may be well suited for this population. OBJECTIVE: The main objectives are (1) to investigate the feasibility and cost-effectiveness of 2 telemedicine approaches for the delivery of an exercise intervention for youth with OI and (2) to assess the impact of the exercise intervention on muscle function and cardiopulmonary fitness in youth with OI. METHODS: Patients with OI type I (the mildest form of OI; n=12, aged 12-16 years) from a pediatric orthopedic tertiary hospital will be randomized to receive a 12-week remote exercise intervention in either (1) a supervised group (n=6), monitored every session, or (2) a follow-up group (n=6), receiving monthly progress update appointments. Participants will undergo the following pre- and postintervention evaluations: sit-to-stand test, push-up test, sit-up test, single-legged balance test, and a heel-rise test. Both groups will be given the same 12-week exercise regimen, which includes cardiovascular, resistance, and flexibility training. For each exercise training session involving the supervised group, a kinesiologist will provide instructions to participants through live video sessions using a teleconferencing application. On the other hand, the follow-up group will discuss their progress with the kinesiologist every 4 weeks over a teleconferencing video call. Feasibility will be assessed by recruitment, adherence, and completion rates. A cost-effectiveness analysis of both approaches will be computed. Changes in muscle function and cardiopulmonary fitness will be examined between the 2 groups, pre- and postintervention. RESULTS: It is anticipated that the supervised group will have higher adherence and completion rates compared to the follow-up group, which may be associated with greater physiological benefits; however, it may not be as cost-effective compared to the follow-up approach. CONCLUSIONS: By determining the most feasible telemedicine approach, this study may serve as a basis for providing increased access to specialized adjunct therapies for individuals with rare disorders. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/40262.

The Design, Development, and Usability Testing of an eHealth Program for Youths With Osteogenesis Imperfecta: Protocol for a 2-Phase User-Centered Mixed Methods Study.

BACKGROUND: Innovative approaches are needed to address the self-management needs of youths with osteogenesis imperfecta (OI) transitioning into adult-oriented health care systems. Using a sequentially phased research approach, the goal is to design, develop, and test the usability of an innovative eHealth program called "Teens Taking Charge: Managing OI Online," hereafter named "Teens OI." This program seeks to optimize self-management, facilitate a successful transition to adult care, and address a critical gap in the quality of care for youths with OI. OBJECTIVE: The study objectives are to (1) design and develop an English and French version of the Teens OI and (2) test the usability of the Teens OI in terms of efficiency, effectiveness, and satisfaction from the perspectives of youths with OI and their parents. METHODS: A user-centered design is presently in progress to design and develop Teens OI. A "Website Design and Development Council" (ie, Council) has been convened, with 20 youths and parent dyads recruited and global experts surveyed at an international meeting. With unanimous support from the Council, usability testing of the Teens OI will ensue in 4 iterative cycles with 32 youth-parent dyads. All sociodemographic and usability metrics will be descriptively analyzed. All recorded interview and focus group data are analyzed using content analysis techniques involving an iterative process of data reduction, data display, conclusion drawing, and verification. RESULTS: As of December 2022, an 8-person, interdisciplinary Teens OI council, comprising 4 health care professionals, 3 youths and young adults with OI, and 1 parent, has been convened to oversee the design and development of Teens OI. Two cycles of interviews have been conducted with 10 youths with OI with or without their parents (n=6) from December 2021 to September 2022. Data analysis has been in progress since April 2022. Aim 2 is ethically approved and will commence following the completion of content development, expected by late July 2023. Preliminary analysis indicates that the following topics need to be prioritized for the youths: mental health, pain, accessibility, medical care, education, community, and parental care. CONCLUSIONS: The proposed study will design and develop a self-management and transitional care program for youths with OI in partnership with patients, caregivers, and health care professionals. This study leverages youths' openness to adopt eHealth technologies to meet their needs and has the potential to actively engage them to autonomously manage their lifelong conditions, and facilitate a successful transition to adult health care. Finally, the proposed study will also address a critical gap in the quality of care and the growing concern that the OI population transitioning from pediatric to adult care is at risk of various adverse events associated with the transition. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/47524.

Limited evidence for graft selection in pediatric ACL reconstruction: a narrative review.

Anterior cruciate ligament reconstruction is the preferred treatment to anterior cruciate ligament injury. With the increase in anterior cruciate ligament injuries in both adults and skeletally immature patients comes the need for individualized anterior cruciate ligament reconstruction graft selection whether it is the type of graft (auto vs. allograft) or the harvesting site (hamstrings, iliotibial band, quadriceps, patella). Several factors need to be considered preoperatively in order to optimize the patients' recovery and restore anterior cruciate ligament strength and function. These include age and bone maturity, preoperative knee flexor/extensor strength, sport participation, patient's needs and anatomical characteristics. This paper aims at bringing evidence supporting the use of a personalized approach in graft selection for faster and more efficient return to sport and propose a theoretical framework to support the approach.

Congruent visual and proprioceptive information results in a better encoding of initial hand position.

Goal-directed movements performed in a virtual environment pose serious challenges to the central nervous system because the visual and proprioceptive representations of one's hand position are not perfectly congruent. The aim of the present study was to determine whether the vision of one's hand or upper arm, compared with that of a cursor representing the tips of one's index finger and thumb, optimizes the planning and modulation of one's movement as the cursor nears the target. The participants performed manual aiming movements that differed by the source of static visual information available during movement planning and the source of dynamic information available during movement execution. The results revealed that the vision of one's hand during the movement planning phase results in more efficient online control processes than when the movement planning was based on a virtual representation of one's initial hand location. This observation was seen regardless of the availability of online visual feedback during movement execution. These results suggest that a more reliable estimation of the initial hand position results in more accurate estimation of the position of the cursor/hand at any one time resulting in more accurate online control.

Suboptimal online control of aiming movements in virtual contexts.

We determined whether uncertainty about the location of one's hand in virtual environments limits the efficacy of online control processes. In the Non-aligned and Aligned conditions, the participant's hand was represented by a cursor on a vertical or horizontal display, respectively. In the Natural condition, participants saw their hand. During an acquisition phase, visual feedback was either permitted or not during movement execution. To test the hypothesis (Norris et al. 2001) that reliance on visual feedback increases as the task becomes less natural (Natural < Aligned < Non-aligned), following acquisition, participants performed a transfer phase without visual feedback. During acquisition in both visual feedback conditions, movement endpoint variability increased as the task became less natural. This suggests that the orientation of the display and the representation of one's hand by a cursor introduced uncertainty about its location, which limits the efficacy of online control processes. In contradiction with the hypothesis of Norris et al. (2001), withdrawing visual feedback in transfer had a larger deleterious effect on movement accuracy as the task became less natural. This suggests that the CNS increases the weight attributed to the input that can be processed without first having to be transformed.

Patient and Parent Experiences with Group Telerehabilitation for Child Survivors of Acute Lymphoblastic Leukemia.

BACKGROUND: Acute Lymphoblastic Leukemia (ALL) is the most common pediatric cancer. ALL and its treatment cause altered bone-mineral homeostasis, which can contribute to musculoskeletal late adverse effects (LAEs). With the increasing number of childhood cancer survivors, LAEs are reported often, and are aggravated by inactive lifestyles. A telerehabilitation program is proposed to strengthen the muscle-bone complex and prevent future impairment. OBJECTIVE: This study aimed to explore and better understand patient and parent experience of a telerehabilitation program after completion of ALL treatment. METHODS: ALL survivors (n = 12), 75% girls, 7.9 to 14.7 years old, within six months to five years of treatment, were recruited to participate in the proposed study, along with a parent. The 16-week group program included 40 potential home-based physical activities, with monthly progression, supervised by a kinesiologist, through an online telerehabilitation platform. Patients could be included in the study if they joined during the first month of intervention of their group (minimum 12 weeks of intervention). A semi-structured post-intervention interview was conducted with the patients and their parent during the final assessment, along with a review of the kinesiologist's clinical notes, to obtain a portrait of the participants' experience with the telerehabilitation program. Overarching themes were identified by one author and confirmed by two senior authors before extracting the various aspects of each theme. RESULTS: Of the 12 patients recruited, three were excluded from the analysis because they did not complete the minimum 12 weeks of intervention (one = relapse, one = failure to meet technical requirements, and one = abandoned due to parent's disinterest). The nine patients who completed the program (six girls; 10.93 ± 2.83 years) had a mean adherence of 89%. The overarching themes identified were the program modalities (group approach with patient-parent paired training, supervised by a kinesiologist), the telerehabilitation system, the participants' perception of the benefits, and recommendations and suggestions from the families. Both patients and parents expressed very high satisfaction with the program and perceived benefits. CONCLUSION: Participants appreciated the program and reported they would all recommend it to other families in similar situations. The telerehabilitation method of service delivery was perceived by some as decisive in choosing to participate, while the supervision and intra- and inter-family interactions were the motivating factors that were key to program adherence.

Home-Based Telehealth Exercise Intervention in Early-On Survivors of Childhood Acute Lymphoblastic Leukemia: Feasibility Study.

BACKGROUND: Acute lymphoblastic leukemia is the most common type of pediatric cancer. Acute lymphoblastic leukemia causes an altered bone mineral homeostasis state, which can contribute to osteopenia, and bone fractures, most commonly vertebral fractures. With the increasing number of childhood cancer survivors, late adverse effects such as musculoskeletal comorbidities are often reported and are further influenced by inactive lifestyle habits. Physical activity has been shown to increase the mechanical workload of the bone, mitigating bone impairment in other cancer-specific populations. OBJECTIVE: This interventional pilot study aims to investigate the use of telehealth to deliver a home-based exercise intervention for early-on survivors of bone marrow-related hematological malignancies and to assess its impact on survivors' musculoskeletal and functional health. METHODS: We aimed to recruit a group of 12 early-on survivors of acute lymphoblastic leukemia, within 6 months to 5 years of treatment, to participate in and complete the proposed telehealth intervention with a parent. The 16-week intervention included 40 potential home-based physical activity interventions supervised by a kinesiologist through a telehealth internet platform, with monthly progression. Patients were recruited to the cohort if they were able to participate in the intervention during the first month (minimum 12 weeks of intervention). Evaluation before and after the intervention protocol highlighted differences in functional capacities and musculoskeletal health of patients using mechanography, peripheral quantitative computed tomography, 6-minute walk test, and grip force test. RESULTS: The recruitment rate for the intervention was low (12/57, 21% of contacted patients). Of 12 patients, 3 were excluded (1=relapse, 1=failure to meet technical requirements, and 1=abandoned). The 9 patients who completed the intervention (6 girls; mean age 10.93, SD 2.83 years; mean BMI 21.58, SD 6.55 kg/m2; mean time since treatment completion 36.67, SD 16.37 months) had a mean adherence of 89% and a completion rate of 75%. In addition, these patients showed functional improvements in lower limb muscle force and power as well as in the 6-minute walk test distance. Participants also showed improved bone health after the intervention on the following parameters: bone mineral content, stress-strain index, total and cortical cross-sectional area at the 14% site (P=.03, P=.01, P=.01, and P=.001, respectively) and 38% site of the tibia (P=.003, P=.04, P=.001, and P=.003, respectively). CONCLUSIONS: High adherence and participation rates suggest that telehealth is a feasible method to deliver exercise interventions to young early-on survivors of acute lymphoblastic leukemia. The proposed intervention seems promising in providing benefits to patients' functional performance and bone health, but a large-scale study is needed to confirm this assumption.