Tibial bone geometry in chronic stroke patients: influence of sex, cardiovascular health, and muscle mass

Elevated sclerostin levels contribute to reduced bone mineral density in non-ambulatory stroke patients

Osteoporosis following stroke is a significant impediment to patient recovery. Decreased mechanical loading and locomotion following the onset of paralysis in stroke patients, especially those who are non-ambulatory, contributes greatly to bone loss. Sclerostin, a protein encoded by the SOST gene, accumulates as a result of reduced mechanical loading and inhibits bone formation. This study explores the relationship between mechanical unloading, sclerostin levels, and bone mineral density (BMD) in stroke patients, utilizing three cohorts. Analysis of Cohort 1, consisting of patients with available sclerostin level measurements, found significantly elevated sclerostin levels in non-ambulatory patients compared to ambulatory patients, indicating the influence of ambulatory status on sclerostin regulation. Cohort 2, consisting of patients with BMD measurements, demonstrated that prolonged mechanical unloading in non-ambulatory patients resulted in a greater decline in BMD over time. Analysis in Cohort 3 patients, who had bilateral BMD measurements available, revealed that hemiplegic sides subjected to reduced mechanical loading exhibited lower BMD compared to non-hemiplegic sides. These findings collectively confirm the hypothesis that reduced mechanical loading elevates sclerostin levels and accelerates bone loss. By integrating data across the three cohorts, this study underscores the critical impact of mechanical unloading on bone health, particularly in chronic stroke patients with limited mobility. Our study provides clinical insights for treatments integrating ambulatory status, sclerostin levels, and BMD in chronic stroke patients and highlights an increased need for therapeutics targeting mechanical loading pathways and sclerostin accumulation which can be administered to treat chronic osteoporosis following stroke.

Clinical Characteristics and Bone Mineral Density Score in Post-Stroke Neuromuscular Deficit

Background

Disuse osteoporosis in hemiparetic patients often results in significant morbidity, decreased quality of life, and different clinical characteristics. The study aimed to investigate the effect of these clinical factors on bone mineral density (BMD).

Methods

This was an analytical observational study with a cross-sectional method evaluating hemiparetic patients at Cipto Mangunkusumo Hospital from 2018 to 2019. BMD (g/cm2) was assessed using dual energy X-ray absorptiometry (DXA) on the spine and both sides of the body. The relationship and correlation between BMD and delta BMD scores with clinical characteristics were analyzed. A linear regression test was used to assess the correlation between variables.

Results

A total of 34 participants were recruited for this study. There was a difference between the healthy and paretic side of BMD of both hip and wrist (P < 0.001), strong positive correlation between the onset of hemiparesis and wrist and hip delta BMD (r = 0.779, P = 0.001 and r = 0.791, P = 0.001), and significant association between delta BMD and age and motor strength. Multivariate analysis shows that the onset of hemiparesis was a strong predictor of delta BMD (aR2 wrist = 0.486, aR2 hip = 0.614). There was a 7.36% decrease in the mean BMD score of the paretic side compared to the non-paretic side.

Conclusion

A low BMD score is prevalent in seven out of 10 patients with post-stroke neuromuscular deficit. Age, limb strength, the onset of hemiparesis, and rehabilitation compliance are associated with decreased BMD among patients with post-stroke neuromuscular deficit.

Non-pharmacological and pharmacological treatments for bone health after stroke: Systematic review with meta-analysis

BACKGROUND

Hemi-osteoporosis is a common secondary complication of stroke. No systematic reviews of pharmacological and non-pharmacological agents for post-stroke bone health have estimated the magnitude and precision of effect sizes to guide better clinical practice.

OBJECTIVES

To examine the benefits and harms of pharmacological and non-pharmacological agents on bone health in post-stroke individuals.

METHODS

Eight databases were searched (PubMed, Cochrane library, Scopus, CINAHL Complete, Embase, PEDro, Clinicaltrils.gov and ICTRP) up to June 2023. Any controlled studies that applied physical exercise, supplements, or medications and measured bone-related outcomes in people with stroke were included. PEDro and the GRADE approach were used to examine the methodological quality of included articles and quality of evidence for outcomes. Effect sizes were calculated as standardized mean differences (SMD) and risk ratio (RR). Review Manager 5.4 was used for data synthetization.

RESULTS

Twenty-four articles from 21 trials involving 22,500 participants (3,827 in 11 non-pharmacological and 18,673 in 10 pharmacological trials) were included. Eight trials were included in the meta-analysis. The methodological quality of half of the included non-pharmacological studies was either poor or fair, whereas it was good to excellent in 8 of 10 pharmacological studies. Meta-analysis revealed a beneficial effect of exercise on the bone mineral density (BMD) of the paretic hip (SMD: 0.50, 95 % CI: 0.16; 0.85; low-quality evidence). The effects of anti-resorptive medications on the BMD of the paretic hip were mixed and thus inconclusive (low-quality evidence). High-quality evidence showed that the administration of antidepressants increased the risk of fracture (RR: 2.36, 95 % CI 1.64-3.39).

CONCLUSION

Exercise under supervision may be beneficial for hip bone health in post-stroke individuals. The effect of anti-resorptive medications on hip BMD is uncertain. The adverse effects of antidepressants on fracture risk among post-stroke individuals warrant further attention. Further high-quality studies are required to better understand this issue.

REGISTRATION

PROSPERO CRD42022359186.

Gait speed and spasticity are independently associated with estimated failure load in the distal tibia after stroke: an HR-pQCT study

This HR-pQCT study was conducted to examine bone properties of the distal tibia post-stroke and to identify clinical outcomes that were associated with these properties at this site. It was found that spasticity and gait speed were independently associated with estimated failure load in individuals with chronic stroke.

PURPOSE

(1) To examine the influence of stroke on distal tibia bone properties and (2) the association between these properties and clinical outcomes in people with chronic stroke.

METHODS

Sixty-four people with stroke (age, 60.8 ± 7.7 years; time since stroke, 5.7 ± 3.9 years) and 64 controls (age: 59.4 ± 7.8 years) participated in this study. High-resolution peripheral quantitative computed tomography (HR-pQCT) was used to scan the bilateral distal tibia, and estimated failure load was calculated by automated finite element analysis. Echo intensity of the medial gastrocnemius muscle and blood flow of the popliteal artery were assessed with ultrasound. The 10-m walk test (10MWT), Fugl-Meyer Motor Assessment (FMA), and Composite Spasticity Scale (CSS) were also administered.

RESULTS

The percent side-to-side difference (%SSD) in estimated failure load, cortical area, thickness, and volumetric bone mineral density (vBMD), and trabecular and total vBMD were significantly greater in the stroke group than their control counterparts (Cohen's d = 0.48-1.51). Isometric peak torque and echo intensity also showed significant within- and between-groups differences (p ≤ 0.01). Among HR-pQCT variables, the %SSD in estimated failure load was empirically chosen as one example of the strong discriminators between the stroke group and control group, after accounting for other relevant factors. The 10MWT and CSS subscale for ankle clonus remained significantly associated with the %SSD in estimated failure load after adjusting for other relevant factors (p ≤ 0.05).

CONCLUSION

The paretic distal tibia showed more compromised vBMD, cortical area, cortical thickness, and estimated failure load than the non-paretic tibia. Gait speed and spasticity were independently associated with estimated failure load. As treatment programs focusing on these potentially modifiable stroke-related impairments are feasible to administer, future studies are needed to determine the efficacy of such intervention strategies for improving bone strength in individuals with chronic stroke.

Relationship between bone strength index of the hemiparetic tibial diaphysis and muscle strength in people with chronic stroke: influence of muscle contraction type and speed

This study was conducted to examine the association between the tibial bone strength index and leg muscle strength of different contraction types and speeds among people with chronic stroke. We found that concentric muscle power at moderate speed was more associated with tibial bone strength index than other types.

INTRODUCTION

To compare the influence of muscle strength of different contraction types and speeds on the bone strength index of tibial diaphysis in people with chronic stroke.

METHODS

Eighty individuals with chronic stroke (age: 62.6 ± 8.0 years; men/women: 46/34; post-stroke duration: 9.0 ± 5.4 years) underwent scanning of the tibia at the 66% site on both sides using peripheral quantitative computed tomography. Each participant was also evaluated for isometric and dynamic (at 60°/s and 120°/s) strength of knee flexors/extensors and ankle dorsiflexors/plantarflexors using an isokinetic dynamometer. For a given contraction type and speed, the strength values of the four muscle groups were summed to yield a composite score. Multiple regression analysis was used to identify the association of the percent side-to-side difference (%SSD) in tibial polar-stress-strain index (p-SSI) with %SSD in muscle strength of different contraction types and speeds.

RESULTS

The p-SSI and all muscle strength parameters on the paretic side had lower values than the non-paretic side (p ≤ 0.001). The %SSD in concentric muscle power at angular speed of 60°/s (R² = 0.317, p = 0.006) and 120°/s (R² = 0.298, p = 0.020) remained independently associated with that in p-SSI, after controlling for age, sex, body mass index, post-stroke duration, motor impairment, spasticity, and physical activity level. The effect of isometric strength and eccentric muscle power was not significant in multivariate analysis.

CONCLUSIONS

Concentric muscle power was more predictive of %SSD in p-SSI at the tibial diaphysis than other contraction types and may be an important target for intervention to promote bone health in people with chronic stroke.

Determinants of estimated failure load in the distal radius after stroke: An HR-pQCT study

Bone health is often compromised after stroke and the distal radius is a common site of fragility fractures. The macro- and mircoproperties of bone tissue after stroke and their clinical correlates are understudied. The objectives of the study were to use High-Resolution peripheral Quantitative Computed Tomography (HR-pQCT) to investigate the bone properties at the distal radius, and to identify the correlates of estimated failure load for the distal radius in people with chronic stroke. This was a cross-sectional study of 64 people with stroke (age: 60.8 ± 7.7 years, stroke duration: 5.7 ± 3.9 years) and 64 age- and sex-matched controls. Bilateral bone structural, densitometric, geometric and strength parameters of the distal radius were measured using HR-pQCT. The architecture, stiffness and echo intensity of the bilateral biceps brachii muscle and brachial artery blood flow were evaluated using diagnostic ultrasound. Other outcomes included the Fugl-Meyer Motor Assessment (FMA), Motor Activity Log (MAL), and Composite Spasticity Scale (CSS). The results revealed a significant side (paretic vs non-paretic for the stroke group, non-dominant vs dominant for controls) by group (stroke vs control) interaction effect for estimated failure load, cortical area, cortical thickness, trabecular number and trabecular separation, and all volumetric density parameters. Post-hoc analysis showed percent side-to-side differences in bone outcomes were greater in the stroke group than the control group, with the exception of trabecular thickness and intracortical porosity. Among the HR-pQCT variables, percent side-to-side difference in trabecular volumetric bone mineral density contributed the most to the percent side-to-side difference in estimated failure load in the stroke group (R² change = 0.334, β = 1.106). Stroke-related impairments (FMA, MAL, CSS) were found to be significant determinants of the percent side-to-side difference in estimated failure load (R² change = 0.233, β = -0.480). This was the first study to examine bone microstructure post-stroke. We found that the paretic distal radius had compromised bone structural properties and lower estimated failure load compared to the non-paretic side. Motor impairment was a determinant of estimated bone strength at the distal radius and may be a potential intervention target for improving bone health post-stroke.

Effects of different vibration frequencies on muscle strength, bone turnover and walking endurance in chronic stroke

This randomized controlled trial aimed to evaluate the effects of different whole body vibration (WBV) frequencies on concentric and eccentric leg muscle strength, bone turnover and walking endurance after stroke. The study involved eighty-four individuals with chronic stroke (mean age = 59.7 years, SD = 6.5) with mild to moderate motor impairment (Fugl-Meyer Assessment lower limb motor score: mean = 24.0, SD = 3.5) randomly assigned to either a 20 Hz or 30 Hz WBV intervention program. Both programs involved 3 training sessions per week for 8 weeks. Isokinetic knee concentric and eccentric extension strength, serum level of cross-linked N-telopeptides of type I collagen (NTx), and walking endurance (6-min walk test; 6MWT) were assessed at baseline and post-intervention. An intention-to-treat analysis revealed a significant time effect for all muscle strength outcomes and NTx, but not for 6MWT. The time-by-group interaction was only significant for the paretic eccentric knee extensor work, with a medium effect size (0.44; 95% CI: 0.01, 0.87). Both WBV protocols were effective in improving leg muscle strength and reducing bone resorption. Comparatively greater improvement in paretic eccentric leg strength was observed for the 30 Hz protocol.

The impact of stroke on bone properties and muscle-bone relationship: a systematic review and meta-analysis

To systematically review available evidence related to the characteristics of bone changes post-stroke and the relationship between various aspects of muscle function (e.g., strength, spasticity) and bone properties after stroke onset. An extensive online database search was undertaken (last search in January 2019). Articles that examined the bone properties in stroke patients were included. The quality of the studies was evaluated with the National Institutes of Health (NIH) Study Quality Assessment Tools. Publication bias of meta-analyses was assessed using the Egger's regression asymmetry test. The selection and evaluation of the articles were conducted by two independent researchers. Fifty-nine studies were identified. In subacute and chronic stroke studies, the skeletal sites in the paretic limbs sustained a more pronounced decline in bone quality than did their counterparts in the non-paretic limbs. The rate of changes showed a decelerating trend as post-stroke duration increased, but the timing of achieving the steady rate differed across skeletal sites. The magnitude of bone changes in the paretic upper limb was more pronounced than the paretic lower limb. There was a strong relationship between muscle strength/mass and bone density/strength index. Muscle spasticity seemed to have a negative impact on bone integrity in the paretic upper limb, but its influence on bone properties in the paretic lower limb was uncertain. Substantial bone changes in the paretic limbs occurred particularly in the first few months after stroke onset. Early intervention, muscle strength training, and long-term management strategies may be important to enhance bone health post-stroke. This review has also revealed the knowledge gaps which should be addressed in future research.

Complicated Muscle-Bone Interactions in Children with Cerebral Palsy

PURPOSE OF REVIEW

The goal of this review is to highlight the deficits in muscle and bone in children with cerebral palsy (CP), discuss the muscle-bone relationship in the CP population, and identify muscle-based intervention strategies that may stimulate an improvement in their bone development.

RECENT FINDINGS

The latest research suggests that muscle and bone are both severely underdeveloped and weak in children with CP, even in ambulatory children with mild forms of the disorder. The small and low-performing muscles and limited participation in physical activity are likely the major contributors to the poor bone development in children with CP. However, the muscle-bone relationship may be complicated by other factors, such as a high degree of fat and collagen infiltration of muscle, atypical muscle activation, and muscle spasticity. Muscle-based interventions, such as resistance training, vibration, and nutritional supplementation, have the potential to improve bone development in children with CP, especially if they are initiated before puberty. Studies are needed to identify the muscle-related factors with the greatest influence on bone development in children with CP. Identifying treatment strategies that capitalize on the relationship between muscle and bone, while also improving balance, coordination, and physical activity participation, is an important step toward increasing bone strength and minimizing fractures in children with CP.

A longitudinal comparison of appendicular bone growth and markers of strength through adolescence in a South African cohort using radiogrammetry and pQCT

To compare growth patterns and strength of weight- and non-weight-bearing bones longitudinally. Irrespective of sex and ethnicity, metacarpal growth was similar to that of the non-weight-bearing radius but differed from that of the weight-bearing tibia. Weight- and non-weight-bearing bones have different growth and strength patterns.

INTRODUCTION

Functional loading modulates bone size and strength.

METHODS

To compare growth patterns and strength of weight- and non-weight-bearing bones longitudinally, we performed manual radiogrammetry of the second metacarpal on hand-wrist radiographs and measured peripheral quantitative computed tomography images of the radius (65%) and tibia (38% and 65%), annually on 372 black and 152 white South African participants (ages 12-20 years). We aligned participants by age from peak metacarpal length velocity. We assessed bone width (BW, mm); cortical thickness (CT, mm); medullary width (MW, mm); stress-strain index (SSI, mm³); and muscle cross-sectional area (MCSA, mm²).

RESULTS

From 12 to 20 years, the associations between metacarpal measures (BW, CT and SSI) and MCSA at the radius (males R² = 0.33-0.45; females R² = 0.12-0.20) were stronger than the tibia (males R² = 0.01-0.11; females R² = 0.007-0.04). In all groups, radial BW, CT and MW accrual rates were similar to those of the metacarpal, except in white females who had lower radial CT (0.04 mm/year) and greater radial MW (0.06 mm/year) accrual. In all groups, except for CT in white males, tibial BW and CT accrual rates were greater than at the metacarpal. Tibial MW (0.29-0.35 mm/year) increased significantly relative to metacarpal MW (- 0.07 to 0.06 mm/year) in males only. In all groups, except white females, SSI increased in each bone.

CONCLUSION

Irrespective of sex and ethnicity, metacarpal growth was similar to that of the non-weight-bearing radius but differed from that of the weight-bearing tibia. The local and systemic factors influencing site-specific differences require further investigation. Graphical abstract.

Peripheral Quantitative Computed Tomography: Review of Evidence and Recommendations for Image Acquisition, Analysis, and Reporting, Among Individuals With Neurological Impairment

In 2015, the International Society for Clinical Densitometry (ISCD) position statement regarding peripheral quantitative computed tomography (pQCT) did not recommend routine use of pQCT, in clinical settings until consistency in image acquisition and analysis protocols are reached, normative studies conducted, and treatment thresholds identified. To date, the lack of consensus-derived recommendations regarding pQCT implementation remains a barrier to implementation of pQCT technology. Thus, based on description of available evidence and literature synthesis, this review recommends the most appropriate pQCT acquisition and analysis protocols for clinical care and research purposes, and recommends specific measures for diagnosis of osteoporosis, assigning fracture risk, and monitoring osteoporosis treatment effectiveness, among patients with neurological impairment. A systematic literature search of MEDLINE, EMBASE^©, CINAHL, and PubMed for available pQCT studies assessing bone health was carried out from inception to August 8th, 2017. The search was limited to individuals with neurological impairment (spinal cord injury, stroke, and multiple sclerosis) as these groups have rapid and severe regional declines in bone mass. Of 923 references, we identified 69 that met review inclusion criteria. The majority of studies (n = 60) used the Stratec XCT 2000/3000 pQCT scanners as reflected in our evaluation of acquisition and analysis protocols. Overall congruence with the ISCD Official Positions was poor. Only 11% (n = 6) studies met quality reporting criteria for image acquisition and 32% (n = 19) reported their data analysis in a format suitable for reproduction. Therefore, based on current literature synthesis, ISCD position statement standards and the authors' expertise, we propose acquisition and analysis protocols at the radius, tibia, and femur sites using Stratec XCT 2000/3000 pQCT scanners among patients with neurological impairment for clinical and research purposes in order to drive practice change, develop normative datasets and complete future meta-analysis to inform fracture risk and treatment efficacy evaluation.

Midfemoral Bone Volume of Walking Subjects with Chronic Hemiparesis Post Stroke

BACKGROUND AND PURPOSE

Muscle and bone form a functional unit. Residual physical poststroke impairments such as muscle weakness, spasticity, and decrease in function can promote metabolic bone changes. Moreover, muscle strength can influence this process. Thus, the purpose of the present study was to investigate bone volume and mobility performance in subjects with chronic hemiparesis post stroke.

METHODS

A cross-sectional study was performed on 14 subjects post stroke who were paired with healthy controls. Bone volume, isometric muscle performance, and mobility levels were measured. Midfemoral bone volumes were determined using magnetic resonance imaging, and muscular performance was measured by dynamometry. Mobility was measured using the Timed Up and Go Test and the 10-Meter Walk Test.

RESULTS

Regarding bone volume total, there was no difference in the medullary and cortical groups (P ≥ .05). During torque peak isometric flexion, the paretic group was significantly different compared with the other groups (P = .001). However, the control presented no difference compared with the nonparetic limb (P = .40). With regard to the extension isometric torque peak, the paretic limb was significantly different compared with the nonparetic (P = .033) and the control (P = .001) limbs, and the control was different from the nonparetic limb (P = .045). Bone volume variables correlated with the isometric torque peak.

CONCLUSIONS

Chronic hemiparetic subjects maintain bone geometry compared with healthy volunteers matched by age, body mass index, and gender. The correlation between bone volume midfemoral structures and knee isometric torque was possible.

Validating accelerometry as a measure of physical activity and energy expenditure in chronic stroke

BACKGROUND

Accelerometers can objectively measure steps taken per day in individuals without gait deficits, but accelerometers also have the ability to estimate frequency, intensity, and duration of physical activity. However, thresholds to distinguish varying levels of activity intensity using the Actical brand accelerometer are standardized only for the general population and may underestimate intensity in stroke.

OBJECTIVE

To derive Actical activity count thresholds specific to stroke disability for use in more accurately gauging time spent at differing activity levels.

METHODS

Men (n = 18) and women (n = 10) with chronic hemiparetic gait (4 ± 2 years latency, 43% Caucasian, 56% African-American, ages of 47-83 years, BMI 19-48 kg/m²) participated in the study. Actical accelerometers were placed on the non-paretic hip to obtain accelerometry counts during eight activities of varying intensity: (1) watching TV; (2) seated stretching; (3) standing stretching; (4) floor sweeping; (5) stepping in place; (6) over-ground walking; (7) lower speed treadmill walking (1.0 mph at 4% incline); and (8) higher speed treadmill walking (2.0 mph at 4% incline). Simultaneous portable monitoring (Cosmed K4b2) enabled quantification of energy cost for each activity in metabolic equivalents (METs, or oxygen consumption in multiples of resting level). Measurements were obtained for 10 min of standard rest and 5 min during each of the eight activities.

RESULTS

Regression analysis yielded the following new stroke-specific Actical minimum thresholds: 125 counts per minute (cpm) for sedentary/light activity, 667 cpm for light/moderate activity, and 1546 cpm for moderate/vigorous activity.

CONCLUSION

Our revised cut points better reflect activity levels after stroke and suggest significantly lower thresholds relative to those observed for the general population of healthy individuals. We conclude that the standard, commonly applied Actical thresholds are inappropriate for this unique population.

Chronic effects of stroke on hip bone density and tibial morphology: a longitudinal study

The study aimed to quantify the long-term effects of stroke on tibial bone morphology and hip bone density. Only the trabecular bone mineral density and bone strength index in the hemiparetic tibial distal epiphysis showed a significant decline among individuals who had sustained a stroke 12-24 months ago.

INTRODUCTION

This study aims to determine the changes in bone density and morphology in lower limb long bones during a 1-year follow-up period and their relationship to muscle function in chronic stroke patients.

METHODS

Twenty-eight chronic stroke patients (12-166 months after the acute stroke event at initial assessment) and 27 controls underwent bilateral scanning of the hip and tibia using dual-energy X-ray absorptiometry and peripheral quantitative computed tomography, respectively. Each subject was re-assessed 1 year after the initial assessment.

RESULTS

Twenty stroke cases and 23 controls completed all assessments. At the end of the follow-up, the paretic tibial distal epiphysis suffered significant decline in trabecular bone density (-1.8 ± 0.6 %, p = 0.006) and bone strength index (-2.7 ± 0.6 %, p < 0.001). More severe decline in the former was associated with poorer leg muscle strength (ρ = 0.447, p = 0.048) and motor recovery (ρ = 0.489, p = 0.029) measured at initial assessment. The loss in trabecular bone density remained significant among those whose stroke onset was 12-24 months ago (p < 0.001), but not among those whose stroke onset was beyond 24 months ago (p > 0.05) at the time of initial assessment. The changes of outcomes in the tibial diaphysis, except for cortical bone mineral content on the non-paretic side (-1.3 ± 0.3 %, p = 0.003), and hip bone density were well within the margin of error for precision.

CONCLUSIONS

There is evidence of continuous trabecular bone loss in the paretic tibial distal epiphysis among chronic stroke patients, but it tends to plateau after 2 years of stroke onset. The steady state may have been reached earlier in the hip and tibial diaphysis.

Muscle volume is related to trabecular and cortical bone architecture in typically developing children

INTRODUCTION

Muscle is strongly related to cortical bone architecture in children; however, the relationship between muscle volume and trabecular bone architecture is poorly studied. The aim of this study was to determine if muscle volume is related to trabecular bone architecture in children and if the relationship is different than the relationship between muscle volume and cortical bone architecture.

MATERIALS AND METHODS

Forty typically developing children (20 boys and 20 girls; 6 to 12y) were included in the study. Measures of trabecular bone architecture [i.e., apparent trabecular bone volume to total volume (appBV/TV), trabecular number (appTb.N), trabecular thickness (appTb.Th) and trabecular separation (appTb.Sp)] in the distal femur, cortical bone architecture [cortical volume, total volume, section modulus (Z) and polar moment of inertia (J)] in the midfemur, muscle volume in the midthigh and femur length were assessed using magnetic resonance imaging. Total physical activity and moderate-to-vigorous physical activity were assessed using an accelerometer-based activity monitor worn around the waist for four days. Calcium intake was assessed using diet records. Relationships among the measures were tested using multiple linear regression analysis.

RESULTS

Muscle volume was moderately-to-strongly related to measures of trabecular bone architecture [appBV/TV (r=0.81), appTb.N (r=0.53), appTb.Th (r=0.67), appTb.Sp (r=-0.71); all p<0.001] but more strongly related to measures of cortical bone architecture [cortical volume (r=0.96), total volume (r=0.94), Z (r=0.94) and J (r=0.92; all p<0.001)]. Similar relationships were observed between femur length and measures of trabecular (p<0.01) and cortical (p<0.001) bone architecture. Sex, physical activity and calcium intake were not related to any measure of bone architecture (p>0.05). Because muscle volume and femur length were strongly related (r=0.91, p<0.001), muscle volume was scaled for femur length (muscle volume/femur length(2.77)). When muscle volume/femur length(2.77) was included in a regression model with femur length, sex, physical activity and calcium intake, muscle volume/femur length(2.77) was a significant predictor of appBV/TV, appTb.Th and appTb.Sp (partial r=0.44 to 0.49, p<0.05) and all measures of cortical bone architecture (partial r=0.47 to 0.54; p<0.01).

CONCLUSIONS

The findings suggest that muscle volume in the midthigh is related to trabecular bone architecture in the distal femur of typically developing children. The relationship is weaker than the relationship between muscle volume in the midthigh and cortical bone architecture in the midfemur, but the discrepancy is driven, in large part, by the greater dependence of cortical bone architecture measures on femur length.

Cardiovascular Stress Induced by Whole-Body Vibration Exercise in Individuals With Chronic Stroke

BACKGROUND

Although whole-body vibration (WBV) has sparked tremendous research interest in neurorehabilitation, the cardiovascular responses to WBV in people with stroke remain unknown.

OBJECTIVE

The aim of this study was to determine the acute effects of different WBV protocols on oxygen consumption (V̇o2), heart rate (HR), rate of perceived exertion (RPE), blood pressure (BP), and rate-pressure product (RPP) during the performance of 6 different exercises among people with chronic stroke (time since onset ≥6 months).

DESIGN

A repeated-measures design was used.

METHODS

Each of the 48 participants experienced all 3 WBV protocols in separate sessions: (1) no WBV, (2) low-intensity WBV (peak acceleration=0.96 unit of gravity of Earth [g]), and (3) high-intensity WBV (1.61g). The order in which they encountered the WBV protocols was randomized, as was the order of exercises performed during each session. Oxygen consumption, HR, and RPE were measured throughout the study. Blood pressure and RPP were measured before and after each session.

RESULTS

Low-intensity and high-intensity WBV induced significantly higher V̇o2 by an average of 0.69 and 0.79 mL/kg/min, respectively, compared with the control condition. These protocols also increased HR by an average of 4 bpm. The 2 WBV protocols induced higher RPE than the control condition during static standing exercise only. Although the diastolic and systolic BP and RPP were increased at the end of each exercise session, the addition of WBV had no significant effect on these variables.

LIMITATIONS

The results are generalizable only to ambulatory and community-dwelling people with chronic stroke.

CONCLUSIONS

Addition of high- and low-intensity WBV significantly increased the V̇o2 and HR, but the increase was modest. Thus, WBV should not pose any substantial cardiovascular hazard in people with chronic stroke.

Influence of chronic stroke impairments on bone strength index of the tibial distal epiphysis and diaphysis

SUMMARY

The influence of various stroke impairments on bone health is poorly understood. This study showed that muscle function and small artery compliance were more strongly associated with the bone strength index at the tibial diaphyseal and epiphyseal regions, respectively. These impairments should be targeted in promoting bone health post-stroke.

INTRODUCTION

This study examined the bone structural properties of the tibial distal epiphysis and diaphysis after chronic stroke and identified the clinical correlates of the bone strength index measured at these sites.

METHODS

The tibial distal epiphysis (4% site) and diaphysis (66% site) were scanned on both sides in 66 chronic stroke patients and 23 control participants using peripheral quantitative computed tomography. Dynamic knee muscle strength, balance function, spasticity, arterial compliance, and endurance were also measured in the stroke group.

RESULTS

At the 4% site, multivariate analysis showed a significant side×group interaction effect (Wilk's lambda=3.977, p<0.001), with significant side-to-side differences in total volumetric bone mineral density (vBMD), trabecular vBMD, and bone strength index in the stroke group, but not in the control group. A significant side×group interaction was also found at the 66% site (Wilk's lambda=4.464, p<0.001), with significant side-to-side differences in cortical vBMD, cortical area, cortical thickness, and bone strength index in the stroke group only. Balance and endurance were independently associated with bone strength index at both tibial sites in the paretic leg (p<0.05) after adjusting for relevant factors in multivariate regression analysis. Small artery compliance and muscle strength were significantly associated with the bone strength index at the 4% site and 66% site, respectively.

CONCLUSIONS

The influence of various stroke impairments on bone was region-specific. While muscle function was more strongly associated with the bone strength index in the diaphyseal region, the effect of vascular health was more apparent in the tibial epiphysis in the paretic leg.

Bone geometry, volumetric bone mineral density, microarchitecture and estimated bone strength in Caucasian females with systemic lupus erythematosus. A cross-sectional study using HR-pQCT

Patients with systemic lupus erythematosus (SLE) have an increased risk of fracture. We used high resolution peripheral quantitative computed tomography (HR-pQCT) to measure bone geometry, volumetric bone mineral density (vBMD), cortical and trabecular microarchitecture and estimated bone strength by finite element analysis (FEA) at the distal radius and tibia to assess bone characteristics beyond BMD that may contribute to the increased risk of fracture. Thirty-three Caucasian women with SLE (median age 48, range 21-64 years) and 99 controls (median age 45, range 21-64 years) were studied. Groups were comparable in radius regarding geometry and vBMD, but SLE patients had lower trabecular number (-7%, p < 0.05), higher trabecular separation (13%, p < 0.05) and lower FEA-estimated failure load compared to controls (-10%, p < 0.05). In tibia, SLE patients had lower total vBMD (-11%, p < 0.01), cortical area (-14%, p < 0.001) and cortical thickness (-16%, p < 0.001) and higher trabecular area (8%, p < 0.05). In subgroup analyses of the premenopausal participants (SLE n = 21, controls n = 63), SLE patients had significantly lower trabecular bone volume fraction [(BV/TV); -17%, p < 0.01], trabecular number (-9%, p < 0.01), trabecular thickness (-9%, p < 0.05) and higher trabecular separation (13%, p < 0.01) and trabecular network inhomogeneity (14%, p < 0.05) in radius along with lower BV/TV (-15%, p < 0.01) and higher trabecular separation (11%, p < 0.05) in tibia. FEA-estimated bone strength was lower in both radius (-11%, p < 0.01) and tibia (-10%, p < 0.05). In conclusion, Caucasian women with SLE compared to controls had fewer and more widely separated trabeculae and lower estimated bone strength in radius and lower total vBMD, cortical area and thickness in tibia.

Predictors of low bone mineral density of the stroke-affected hip among ambulatory individuals with chronic stroke

Risk of hip fracture is greater poststroke than in an age-matched healthy population, in part because of declining hip BMD. We found that individuals may be at risk of loss of hip BMD from muscle atrophy, asymmetrical gait, and poor affected-side ankle dorsiflexor strength. These impairments may be targeted during rehabilitation.

INTRODUCTION

This study aimed to determine predictors of low hip BMD on the stroke-affected side in people living in the community.

METHODS

Forty-three participants (female; 27.9%), mean age 62.4 ± 13.5 and 17.9 ± 32.8 months, poststroke with motor impairments underwent dual energy X-ray absorptiometry scans. Gait characteristics, isometric strength, body composition, and fasting plasma lipids were measured.

RESULTS

At entry, 34.9% (15/43) of the participants had low total hip BMD on the stroke-affected side. Of those with low BMD, 93.3% (14/15) had a step length symmetry ratio >1, indicating greater reliance on the non-paretic leg for weight bearing. Logistic regression analysis revealed that lower affected-side ankle dorsiflexor strength (ß = 0.700, p = 0.02), lower total body fat-free mass index (ß = 0.437, p = 0.02), and greater step length symmetry ratio during walking (ß = 1.135 × 10(3), p = 0.03) were predictors of low hip BMD.

CONCLUSION

Low BMD of the stroke-affected side hip is prevalent in over a third of individuals with lower limb motor impairments. These individuals may be at particular risk of accelerated loss of BMD at the hip from asymmetrical gait pattern and poor affected-side ankle dorsiflexor strength. These impairments are intervention targets that may be addressed during rehabilitation which includes resistance training and addresses gait impairments.

Changes to volumetric bone mineral density and bone strength after stroke: a prospective study

RATIONALE AND AIM

Stroke survivors experience accelerated bone loss and increased fracture risk, particularly in paretic weight bearing limbs. Understanding how these changes unfold and their relationship to stroke severity and physical activity could help in the development of targeted interventions to prevent or reduce the severity of these outcomes. The primary aim of this study is to investigate the time course and magnitude of changes in volumetric bone mineral density within the first year after stroke, and to examine relationships with physical activity and motor recovery.

DESIGN

This is a prospective, observational study of 43 nondiabetic, nonambulant adults with first ever hemispheric stroke.

PRIMARY OUTCOME

The primary outcome was the difference in six-month change of total volumetric bone mineral density between paretic and nonparetic distal tibiae, measured at 7% of bone length site using high-resolution peripheral quantitative computed tomography.

SECONDARY OUTCOMES

The secondary outcomes are cortical and trabecular volumetric bone mineral density, cortical thickness, and total and cross-sectional areas of distal tibiae and radii of paretic and nonparetic limbs. Also included are total body and regional bone mineral density derived using dual-energy X-ray absorptiometry, physical activity measured using accelerometry, and motor recovery (Chedoke McMaster Stroke Assessment).

DISCUSSION

Measuring the timing and magnitude of changes to volumetric bone mineral density and bone structure from immediately after stroke, and relationships between these changes with physical activity and motor recovery will provide the basis for targeted interventions to reduce fracture risk in stroke survivors.

Physical Activity after Stroke: A Systematic Review and Meta-Analysis

Background and Purpose. Physical activity is beneficial after stroke, but it is unclear how active stroke survivors are. This systematic review and meta-analysis sought to determine levels of activity and factors predicting activity. Summary of Review: Methods. MEDLINE (1946 to present) and EMBASE (1980 to present) were systematically searched until July 2012. All studies quantifying whole-body-free living physical activity by objective and self-reported methods in a community dwelling population with stroke were included. A random effect meta-analysis was performed. Results. Twenty-six studies were included (n=1105), of which eleven (n=315) contained sufficient data for meta-analysis. There were heterogeneous designs, measurements, and procedures. The studies generally recruited small samples of high-functioning participants. Level of physical activity was generally low in quantity, duration and intensity. Poorer walking ability, specific sensorimotor functions, and low mood were correlates of low physical activity. Meta-analysis generated an estimate of 4355.2 steps/day (95% CI: 3210.4 to 5499.9) with no significant heterogeneity (I2 = 0). Conclusions. In high-functioning stroke survivors, physical activity including walking was generally low. Strategies are needed to promote and maintain physical activity in stroke survivors. Research is needed to establish reasons for low physical activity after stroke.

Vascular elasticity and grip strength are associated with bone health of the hemiparetic radius in people with chronic stroke: implications for rehabilitation

BACKGROUND

People with stroke often have increased bone loss and fracture rate. Increasing evidence has demonstrated a link between cardiovascular health and bone loss in other patient populations.

OBJECTIVE

The study objectives were: (1) to compare the bone density and geometry of the radius diaphysis on the left and right sides in people with chronic stroke and people who were matched for age (control participants) and (2) to examine the relationship between the bone strength index at the hemiparetic radius diaphysis and vascular health in people with chronic stroke.

DESIGN

This was a case-control study.

METHODS

The radius diaphysis on both sides was scanned with peripheral quantitative computed tomography in 65 participants with chronic stroke and 34 control participants. Large-artery and small-artery elasticity indexes were evaluated with a cardiovascular profiling system.

RESULTS

The paretic radius diaphysis had significantly lower values for cortical bone mineral density, cortical thickness, cortical area, and the bone strength index but a larger marrow cavity area than the nonparetic radius diaphysis in participants with chronic stroke, whereas no bone measurement showed a significant side-to-side difference in control participants. Multiple regression analyses showed that the large-artery elasticity index and grip strength remained significantly associated with the bone strength index at the hemiparetic radius diaphysis after controlling for age, sex, time since stroke diagnosis, body mass index, and physical activity (R(2)=.790).

LIMITATIONS

This study was cross-sectional and could not establish causality. The radius diaphysis is not the most common site of fracture after stroke.

CONCLUSIONS

Both the integrity of the vasculature and muscle strength were significantly associated with the bone strength index at the hemiparetic radius diaphysis in participants with chronic stroke. The results may be useful in guiding rehabilitative programs for enhancing bone health in the paretic arm after stroke.

Changes in bone density and geometry of the upper extremities after stroke: a case report

PURPOSE

The purpose of this study was to examine changes in bone density and geometry of the forearm region and motor function of the paretic upper extremity in a person with subacute stroke. Client Description: The participant was a 48-year-old man with right hemiparesis.

INTERVENTION

Not applicable. Measures and Outcomes: The assessment of upper-extremity (UE) function and bone imaging took place at 3 months and 12 months after stroke. The participant had moderate motor impairment and severe disuse of the paretic UE 3 months after stroke. During the follow-up period, no substantial change in paretic UE function was observed. At the 12 month follow-up, the areal bone mineral density (aBMD) of the ultradistal and mid-regions of the paretic forearm, as measured by dual-energy X-ray absorptiometry, sustained a significant reduction of 7.9% and 5.9%, respectively. The non-paretic side, in contrast, had a significant 4.0% increase in aBMD of the mid-forearm and a 2.8% increase in aBMD of the total forearm. Significant findings from peripheral quantitative computed tomography were a reduction in total volumetric bone mineral density (-12.1%) and bone strength index (-20.6%) in the radius distal epiphysis on the paretic side and an increase in cortical bone mineral content (2.0%) and bone strength index (7.6%) in the radius diaphysis on the non-paretic side.

IMPLICATIONS

After a stroke that resulted in moderate to severe UE impairment, a significant decline in bone mineral density was identified in various skeletal sites in the forearm region as the participant entered the subacute and chronic stages of recovery. The results point to the potential importance of early rehabilitative intervention in preventing unfavourable bone changes in the paretic upper limb among individuals with stroke.

Differences in tibia morphology between the sound and affected sides in ankle-foot orthosis-using survivors of stroke

OBJECTIVE

To examine differences in tibia and proximal femur morphology between the affected and sound limbs in ankle-foot orthosis (AFO)-using survivors of stroke.

DESIGN

Observational study.

SETTING

A university bone density laboratory.

PARTICIPANTS

Ambulatory, AFO-using survivors of stroke (N=9; age range, 55-74y; poststroke duration, 13.5±4.4y; AFO use, 6.5±1.4y).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Total body and hip areal bone mineral density (aBMD) and bone mineral content (BMC) were assessed by dual-energy x-ray absorptiometry. The 4%, 38%, and 66% sites of both tibias were measured with peripheral quantitative computed tomography for total, cortical, and trabecular volumetric BMD (vBMD) and BMC. Bone geometry, bone strength index (BSI), strength strain index (SSI), and minimum and maximum rotated moments of inertia (Imin, Imax) were determined.

RESULTS

Total hip and trochanter BMC and aBMD were 7% to 19% greater on the sound side (P<.05). Total BMC and vBMD were 2% to 21% greater (P<.05) on the sound limb, depending on site. Trabecular BMC and vBMD and BSI values were 19%, 21%, and 31% higher (P<.05) on the sound limb at the 4% site. Cortical BMC and vBMD (P<.05), and cortical thickness (P<.01) were greater on the sound side at the 38% and 66% sites. Cortical area and bone strength (SSI, Imin) were greater (P<.05) at the 66% site. Endosteal circumferences were greater on the affected side (P<.01).

CONCLUSIONS

Interlimb differences in bone characteristics after a stroke persist despite returning to ambulatory status with AFO use.

Relative impact of neuromuscular and cardiovascular factors on bone strength index of the hemiparetic distal radius epiphysis among individuals with chronic stroke

The objective of this study was to examine the associations of neuromuscular and cardiovascular impairments with the bone strength index of the hemiparetic distal radius epiphysis in chronic stroke survivors. The results showed that grip strength is the most predominant predictor of the bone strength index.

INTRODUCTION

The purpose of the study was to examine the associations of neuromuscular and cardiovascular impairments with the bone strength index of the hemiparetic distal radius epiphysis in chronic stroke survivors.

METHODS

Sixty-five chronic stroke survivors and 34 healthy control subjects underwent scanning of the distal radius epiphyseal site on both sides using peripheral quantitative computed tomography to measure trabecular volumetric bone mineral density (vBMD) (mg/cm(3)), total vBMD (mg/cm(3)), total area (mm(2)), and compressive bone strength index (cBSI) (g(2)/cm(4)). Various indicators of neuromuscular (grip strength, spasticity) and cardiovascular function (vascular elasticity, oxygen consumption during 6-min walk test) were evaluated.

RESULTS

Analysis of variance revealed a significant main effect of side (p < 0.001) and group × side interaction (p < 0.05) for total BMC, total vBMD, trabecular vBMD, and cBSI (p < 0.05), with the stroke group showing greater side-to-side difference in these variables. However, no significant side-to-side difference in total area was detected in either group (p > 0.05). Sex-specific analysis yielded similar results. Multiple regression analyses revealed that the cBSI of the hemiparetic distal radius epiphysis had a stronger association with neuromuscular factors than cardiovascular factors. Overall, grip strength was the strongest determinant of the cBSI of the hemiparetic distal radius epiphysis (p < 0.01).

CONCLUSIONS

Muscle weakness is the most predominant determinant of cBSI in the hemiparetic distal radius epiphysis among chronic stroke patients. Future studies should investigate the efficacy of different muscle-strengthening strategies in enhancing bone strength of this skeletal site in the chronic stroke population.

Mechanical factors and bone health: effects of weightlessness and neurologic injury

Bone is a dynamic tissue with homeostasis governed by many factors. Among them, mechanical stimuli appear to be particularly critical for bone structure and strength. With removal of mechanical stimuli, a profound bone loss occurs, as best observed in the extreme examples following exposure to space flight or neurologic impairment. This review provides an overview of the changes in bone density and structure that occur during and after space flight as well as following neurologic injury from stroke and spinal cord injury. It also discusses the potential mechanisms through which mechanical stimuli are postulated to act on bone tissue.

Compromised bone strength index in the hemiparetic distal tibia epiphysis among chronic stroke patients: the association with cardiovascular function, muscle atrophy, mobility, and spasticity

SUMMARY

The purpose of this study was to identify the determinants of the bone strength index of the distal tibia epiphysis in chronic stroke patients. The results showed that lower cardiovascular fitness, more muscle atrophy, poorer mobility, and more severe spasticity were independently associated with lower tibial bone strength index.

INTRODUCTION

To identify the determinants of the bone strength index (BSI) at the distal tibia in chronic stroke patients

METHODS

Sixty-three chronic stroke survivors underwent scanning of the distal tibia at the 4% site on both sides using peripheral quantitative computed tomography. The primary outcomes were trabecular bone mineral density (BMD; milligram per cubic centimeter), total BMD (milligram per cubic centimeter), total bone area (square millimeter), and BSI (square gram per centimeter to the power of four). Cardiovascular fitness, leg lean mass, gait velocity, and spasticity were also measured.

RESULTS

Scans from 45 subjects were deemed to have acceptable quality and were included for subsequent analysis. The paretic side had significantly lower trabecular BMD, total BMD, and BSI than the nonparetic side (p < 0.05). However, the total bone area demonstrated no significant side-to-side difference (p > 0.05). After adjusting for relevant biological factors, peak oxygen consumption, leg muscle mass, and gait velocity remained positively associated with tibial BSI on both sides (R (2) change = 6.9-14.2%), whereas spasticity of the paretic leg was negatively associated with tibial BSI on the same side (R (2) change = 4.8%).

CONCLUSIONS

Cardiovascular function, muscle atrophy, mobility, and spasticity are independently associated with BSI of the distal tibia epiphysis among chronic stroke patients.

Structural analysis of the human tibia by tomographic (pQCT) serial scans

This study analyses the evaluation of tomographic indicators of tibia structure, assuming that the usual loading pattern shifts from uniaxial compression close to the heel to a combined compression, torsion and bending scheme towards the knee. To this end, pQCT scans were obtained at 5% intervals of the tibia length (S5-S95 sites from heel to knee) in healthy men and women (10/10) aged 20-40 years. Indicators of bone mass [cortical area, cortical/total bone mineral content (BMC)], diaphyseal design (peri/endosteal perimeters, cortical thickness, circularity, bending/torsion moments of inertia - CSMIs), and material quality [(cortical vBMD (bone mineral density)] were determined. The longitudinal patterns of variation of these measures were similar between genders, but male values were always higher except for cortical vBMD. Expression of BMC data as percentages of the minimal values obtained along the bone eliminated those differences. The correlative variations in cortical area, BMC and thickness, periosteal perimeter and CSMIs along the bone showed that cortical bone mass was predominantly associated with cortical thickness toward the mid-diaphysis, and with bone diameter and CSMIs moving more proximally. Positive relationships between CSMIs (y) and total BMC (x) showed men's values shifting to the upper-right region of the graph and women's values shifting to the lower-left region. Total BMC decayed about 33% from S5 to S15 (where minimum total BMC and CSMI values and variances and maximum circularity were observed) and increased until S45, reaching the original S5 value at S40. The observed gender-related differences reflected the natural allometric relationships. However, the data also suggested that men distribute their available cortical mass more efficiently than women. The minimum amount and variance of mass indicators and CSMIs, and the largest circularity observed at S15 reflected the assumed adaptation to compression pattern at that level. The increase in CSMIs (successively for torsion, A-P bending, and lateral bending), the decrease in circularity values and the changes in cortical thickness and periosteal perimeter toward the knee described the progressive adaptation to increasing torsion and bending stresses. In agreement with the biomechanical background, the described relationships: (i) identify the sites at which some changes in tibial stresses and diaphyseal structure take place, possibly associated with fracture incidence; (ii) allow prediction of mass indicators at any site from single determinations; (iii) establish the proportionality between the total bone mass at regions with highly predominant trabecular and cortical bone of the same individual, suitable for a specific evaluation of changes in trabecular mass; and (iv) evaluate the ability of bone tissue to self-distribute the available cortical bone according to specific stress patterns, avoiding many anthropometric and gender-derived influences.

Fitness and Mobility Exercise (FAME) Program for stroke

Given the potential of exercise to positively influence so many physical and psychosocial domains, the Fitness and Mobility Exercise (FAME) Program was developed to address the multiple impairments arising from the chronic health condition of stroke. We present the details of this exercise program and the evidence which has shown that the FAME Program can improve motor function (muscle strength, balance, walking), cardiovascular fitness, bone density, executive functions and memory. The FAME Program can help to improve the physical and cognitive abilities of people living with a stroke and reduce the risk of secondary complications such as falls, fractures and heart disease.

The Effects of Treadmill Exercise Training on Hip Bone Density and Tibial Bone Geometry in Stroke Survivors: A Pilot Study

Background. Individuals with stroke often sustain bone loss on the hemiparetic side and are prone to fragility fractures. Exercise training may be a viable way to promote bone mineral density (BMD) and geometry in this population. Objective. This was a pilot study to evaluate the effects of a 6-month treadmill exercise program on hip BMD and tibial bone geometry in chronic stroke survivors. Methods. Twenty-one individuals with chronic stroke, with a mean age of 64.5 years and mean poststroke duration of 8.3 years participated in the study. The treatment group underwent a treadmill gait exercise program (two 1-hour sessions per week for 6 months), whereas the control group participated in their usual self-selected activities in the community. The primary outcomes were hip BMD and bone geometry of the midshaft tibia on the paretic side, whereas the secondary outcomes were gait velocity, endurance, leg muscle strength, balance self-efficacy, and physical activity level. Mann-Whitney U tests were used to compare the change in all outcome variables between the 2 groups after treatment. Results. Significant between-group differences in change scores of tibial cortical thickness ( P = .016), endurance ( P = .029), leg muscle strength on the paretic side ( P < .001) and nonparetic side ( P < .001), balance self-efficacy ( P = .016), and physical activity level ( P = .023) were found. Conclusion . The treadmill exercise program induced a modest improvement in tibial bone geometry in individuals with chronic stroke. Further studies are required to explore the optimal training protocol for promoting favorable changes in bone parameters following stroke.

An assessment of the osteogenic index of therapeutic exercises for stroke patients: relationship to severity of leg motor impairment

SUMMARY

Exercise may be a viable way to promote bone health in stroke survivors. This study used the osteogenic index to evaluate the osteogenic potential of selected exercises for stroke survivors. The results show that brisk walking and stepping may be good skeletal loading exercises for this population.

INTRODUCTION

Exercise may induce positive effects on bone health in stroke patients. The purpose of this study was to evaluate the osteogenic potential of selected exercises for stroke survivors.

METHODS

Sixty stroke patients were categorized into group 1 (moderate to severe leg motor impairment) and group 2 (mild to moderate impairment). Each subject performed five exercises in random order: walking at self-selected speed, walking at maximal speed, stepping onto a 6-in. riser, sit-to-stand, and jumping. The peak ground reaction force (GRF) on the hemiparetic side and the number of loading cycles achieved in 1 min were determined. The osteogenic index (OI) was computed for each exercise, based on the formula: OI = Peak GRF (in body weight) x In (number of loading cycles + 1). Two-way analysis of variance was used to compare the OI among the five exercises between the two groups.

RESULTS

For group 1, stepping had significantly higher OI than other exercises (p < 0.001). For group 2, both walking at maximal speed and stepping had significantly higher OI than other exercises (p < 0.001).

CONCLUSIONS

Stepping had the highest OI for those with more severe leg motor impairment. Both stepping and brisk walking had superior OI for those with mild leg motor impairment.

Bone health in stroke

In 2004 the Stroke Association stated ‘Each year over 130,000 people in England and Wales have a stroke. Of all people who suffer from a stroke, about a third are likely to die within the first 10 days, about a third are likely to make a recovery within one month and about a third are likely to be left disabled and needing rehabilitation. Stroke has a greater disability impact than any other medical condition. A quarter of a million people are living with long-term disability as a result of stroke in the UK.’