Paretic Lower Limb Research Articles

Changes in presynaptic inhibition during movement restriction of unilateral lower limb in a hemiparetic patient and healthy individuals

WCN 2013 No: 1168 Topic: 36 — Other topic Changes in presynaptic inhibition during movement restriction of unilateral lower limb in a hemiparetic patient and healthy individuals M. Morishita, H. Yamaguchi, K. Egawa, A. Hirohata, M. Kobayashi. Kibi International University, Takahashi, Japan; Watanabe Hospital, Shiseikai Medical Corporation, Niimi, Japan; Graduate School, Waseda University, Tokorozawa, Japan Background:We previously reported that movement restriction of the non-paretic lower limb improved gait patterns in hemiparetic patients. Objective: We assessed presynaptic inhibition (PI) to determine if movement restriction of the non-paretic lower limb is regulated by upper motor neuron mechanisms in hemiparetic patients compared with healthy individuals. Patients and methods: This study included one hemiparetic patient and 16 young healthy individuals. Participants walked with a knee brace on the non-paretic/non-dominant side. The subjects walked normally for about 10 min and then with the brace for another 10 min (gait training period). PI was measured before and after every 5 min in both conditions. PI was assessed in the soleus muscle on the paretic/ dominant side, and conditioning stimulation of the common peroneal nerve was used prior to soleus H-reflex measurement. Results: The single limb support time for the paretic/dominant side was longer after gait training in both the hemiparetic and healthy individuals. Two-way ANOVA revealed a significant interaction for time and restriction effects in healthy individuals. After gait training, PI was greater than during normal walking conditions in healthy individuals. In the hemiparetic patient, only slight PI was observed before gait training, but PI appeared to the same degree as in healthy individuals after gait training. Conclusion: Our results suggest that gait training with a knee brace may be effective not only for improvement of gait patterns, but also for regulation of upper motor neuron systems caused by increasing weight bearing ratio in paretic lower limbs. doi:10.1016/j.jns.2013.07.2152 Abstract — WCN 2013 No: 1165 Topic: 36 — Other topic Comparison of reposition rate between headshaking maneuver and vibration maneuver in ageotrophic horizontal BPPV H.S. Han, D.S. Shin. Neurology, St Carollo Hospital, Suncheon-si, Republic of Korea Background: Benign paroxysmal positional vertigo (BPPV) is one of the most commondisorders causingdizziness. Posterior Canal(PC)-BPPVhas been said to account for 60–90% of all BPPV cases, and Horizontal Canal(HC)-BPPV for 5–30% of the cases. However, HC-BPPV now appears to be more prevalent than was previously thought. The apogeotropic type is usually persistent, resistant to reposition maneuver, and its pathophysiology is cupulolithiasis in majority. We compare reposition rate between headshaking with modified Semont maneuver and vibration with modified Semont maneuver. Method: The subjectwere 64 patientswith ageotrophic type of HC-BPPV whowere diagnosed by the supine roll test using videonystagmography. We perform modified Semont maneuver after headshaking on 33 patients. We performed modified Semont maneuver after vibration on 31 patients. The patients with remaining vertigo after maneuver were retreated with the same method. After 1 week, We interviewed all patients using call whether vertigo has subsided. 4 patients had vertigo but they didn't come to the hospital because of private reason (3 in headshaking group and 1 in vibration group). We count the number of performance and compare with headshaking group and vibration group. Result: Fifty twice maneuvers were performed in headshaking group and fiftieth maneuvers were performed in vibration group (P N 0.05). The more vertigo is severe, the less maneuver was performed in both groups. Conclusion: There is no significant difference in recurrence rate between headshaking group and vibration group. doi:10.1016/j.jns.2013.07.2153 Abstract — WCN 2013 No: 1163 Topic: 36 — Other topic Symbiosis of neuro-interventionists: From parallel practice to interdisciplinary patient care WCN 2013 No: 1163 Topic: 36 — Other topic Symbiosis of neuro-interventionists: From parallel practice to interdisciplinary patient care T.W. Leung, M. Tang, A. Chan, G.K. Wong, S.C. Yu. Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong Special Administrative Region Backgrounds: In centers with endovascular service established by radiologists, neurosurgeon, cardiologists and/or vascular surgeons, budding interventional neurologists may struggle to portray their role. Objective: In a university teaching hospital, we delivered neurointerventional treatment by a team-oriented approach consisting of radiologists, neurosurgeons and interventional neurologists. We aimed to evaluate this multidisciplinary patient care model through a quantitative framework construct survey. Methods: Responded on a voluntary basis, doctors, nurses, and radiographers defined the existing mode of collaboration over a continuum with parallel practice and non-hierarchical integration at both ends, and gave opinions on 4 major aspects: philosophy (believes in benefits of interprofessional collaboration and knowledge of each other's treatment approach), trust, process (knowledge exchange, physician centrality and conflicts associated with interprofessional collaboration) and outcomes (job satisfaction, personal growth, intention to leave in the following year, and research output). Abstracts / Journal of the Neurological Sciences 333 (2013) e579–e628 e618

HEART RATE VARIABILITY AND SUBJECTIVE RESPONSES IN PATIENTS WITH STROKE: INFLUENCE OF POSTURES AND RESISTIVE EXERCISES

ObjectivesStroke survivors experience the loss of muscle mass and muscle atrophy changes on the paretic lower limbs as well as the non-paretic side. Traditional stroke rehabilitation intervention concerned whether the...

Relationships between functional and structural corticospinal tract integrity and walking post stroke

ObjectiveStudies on upper limb recovery following stroke have highlighted the importance of the structural and functional integrity of the corticospinal tract (CST) in determining clinical outcomes. However, such relationships have not been fully explored for the lower limb. We aimed to test whether variation in walking impairment was associated with variation in the structural or functional integrity of the CST. MethodsTranscranial magnetic stimulation was used to stimulate each motor cortex while EMG recordings were taken from the vastus lateralis (VL) bilaterally; these EMG measures were used to calculate both ipsilateral and contralateral recruitment curves for each lower limb. The slope of these recruitment curves was used to examine the strength of functional connectivity from the motor cortex in each hemisphere to the lower limbs in chronic stroke patients and to calculate a ratio between ipsilateral and contralateral outputs referred to as the functional connectivity ratio (FCR). The structural integrity of the CST was assessed using diffusion tensor MRI to measure the asymmetry in fractional anisotropy (FA) of the internal capsule. Lower limb impairment and walking speed were also measured. ResultsThe FCR for the paretic leg correlated with walking impairment, such that greater relative ipsilateral connectivity was associated with slower walking speeds. Asymmetrical FA values, reflecting reduced structural integrity of the lesioned CST, were associated with greater walking impairment. FCR and FA asymmetry were strongly positively correlated with each other. ConclusionsPatients with relatively greater ipsilateral connectivity between the contralesional motor cortex and the paretic lower limb were more behaviorally impaired and had more structural damage to their ipsilesional hemisphere CST. SignificanceMeasures of structural and functional damage may be useful in the selection of therapeutic strategies, allowing for more tailored and potentially more beneficial treatments.

Isokinetic knee extension and flexion strength in individuals with hemiparesis after stroke

The aim of this study was to assess knee extensor and flexor muscle torque in individuals with hemiparesis after stroke and determine the relationship with muscle tone. Fifty individuals (mean age 58 +/- 6.4 years), 6 to 48 months after stroke, participated in the study. Maximal concentric knee extension and flexion torque at 60 degrees/s and 120 degrees/s and maximal eccentric knee extension contractions at 60 degrees/s were measured with a Biodex dynamometer. Muscle tone was assessed with the modified Ashworth Scale. The relative weakness in the paretic knee muscles ranged from 30% to 42% and was greater for the flexors and at higher velocities (p < 0.05). The knee flexion/extension torque ratio in the non-paretic lower limb was 0.53 for both velocities and significantly lower (p < 0.01) for the paretic lower limb (0.44 at 60 degrees/s and 0.39 at 120 degrees/s). The eccentric/concentric ratio in the paretic lower limb (1.66) was significantly higher (p < 0.05) than in the non-paretic lower limb (1.31). Concentric torque in the paretic lower limb was significantly correlated (p < 0.05) with muscle tone. In conclusion, post-stroke weakness of the knee muscles was most prominent in the flexors and at higher velocities, whereas eccentric strength seemed to be preserved. Strength was also associated with the spasticity that can occur after stroke. This post-stroke muscle weakness pattern could be of importance for gait performance and should therefore be accommodated when planning rehabilitation interventions. (Less)

시각 흐름 속도에 따른 가상현실 프로그램이 뇌졸중 환자의 보행에 미치는 영향

본 연구는 시각흐름 속도에 따른 가상현실 프로그램이 뇌졸중 환자의 보행에 미치는 영향을 알아보고자 시행하였다. 연구 대상자는 서울시 소재 M재활전문병원에 입원 중인 뇌졸중 환자 중 무작위로 31명을 선정하였고 대상자는 가상현실 프로그램에 몰입하여 보행분석기 위에서 보행을 실시하였으며 가상현실 프로그램의 4가지 조건은 정상 보행과 0.25배, 1배, 2배의 시각흐름 속도변환 가상현실 프로그램으로 구성되었다. 중재동안 보행분석은 GaitRite보행분석시스템을 이용하여 보행 속도, 분속수, 활보장, 보장, 단하지지지 시간, 양하지지지 시간을 측정하였다. 그 결과 0.25배의 느린 시각흐름 가상현실 프로그램에서 연구 대상자는 보행속도, 분속수, 환측 활보장, 건측 활보장, 환측 보장, 건측 활보장이 통계적으로 유의하게 감소하였고(p<.05), 환측 단하지지지시간, 건측 단하지지지시간, 환측 양하 지지지시간, 건측 양하지지지시간이 통계적으로 유의하게 증가하였다(p<.05). 또한 2배의 빠른 시각흐름 가상현실 프로그램에서 연구 대상자는 보행속도, 분속수, 환측 활보장, 건측 활보장, 환측 보장, 건측 활보장, 환측 단하지지지시간이 유의하게 증가하였고(p<.05), 건측 단하지지지시간, 환측 양하지지지시간, 건측 양하지지지시간이 유의하게 감소하였다(p<.05). 따라서 가상현실 보행 프로그램의 적용 속도에 따라서 뇌졸중 환자의 보행 능력이 유의하게 차이를 나타낸다는 것을 알았다. 그러므로 뇌졸중 환자의 운동 프로그램을 계획할 때 보행 훈련 프로그램을 증가시킬 수 있는 다양한 훈련 프로그램이 요구된다. The purpose of this study was to evaluate the effects of a visual flow speed's modulation-based VR(virtual reality) program on gait function in stroke patients. Thirty one stroke patients were randomly selected at Dep. of Rehabilitation medicine of M hospital in Seoul. We carried out the gait analysis by dividing them with four conditions : one condition had applied without the visual flow modulation-based VR and another had done three visual flow speed's modulation-based VR(0.25, 1, 2 times). The gait analysis was used with GaitRite system. The data were collected using gait velocity, cadence, stride length, step length, single support time, and double support time during treatment. The results were as follows. First, the slow visual flow(0.25 times)-based VR program on the condition was significant decrease gait velocity, cadence, stride length, step length and increase single support time, double support time(p<.05). Second, the fast visual flow(2 times)-based VR program on the condition was significant increase gait velocity, cadence, stride length, step length, single support time on paretic lower limb and decrease single support time on non-paretic lower limb, double support time(p<.05). Third, the normal visual flow(1 times)-based VR program on the condition was not significant differ gait velocity, cadence, stride length, step length, single support time, double support time. In conclusion, the visual flow speed's modulation-based VR program improves gait function in chronic stroke patients.

When Might a Cane Be Necessary for Walking Following a Stroke?

Background. For individuals with lateral postural imbalance after stroke, the decision to adopt a cane for walking often is not based on objective findings. Objective. The authors investigated the explanatory value of 2 posturographic criteria for lateral postural imbalance on the walking abilities of poststroke subjects. Methods. Indices of postural asymmetry (percentage of body weight on the less loaded lower limb) and instability (mediolateral variance of center-of-pressure displacements) were measured in 40 healthy individuals and 52 patients (mean 94.2 days after first hemispheric stroke), who stood still on a double force platform. Cut-off values (mean ± 2 standard deviations) were calculated and compared. The predictive value of both postural indices on walking abilities with or without a cane was analyzed. Results. Of the patients, 34.6% were unstable along the mediolateral axis (variance >7 mm2), and 44.2% were asymmetrical (body weight <40%); 30% needed a technical aid and 35% walked without a cane. The probability of being able to walk without a cane was less than 5% if the paretic lower limb was not loaded more than 40%. The postural instability index was less informative. Conclusions. This study suggests that patients who do not load more than 40% of their body weight on their paretic lower limb may benefit from the prescription of a cane.

Clinical efficacy and prognostic indicators for lower limb pedalling exercise early after stroke: Study protocol for a pilot randomised controlled trial

BackgroundIt is known that repetitive, skilled, functional movement is beneficial in driving functional reorganisation of the brain early after stroke. This study will investigate a) whether pedalling an upright, static exercise cycle, to provide such beneficial activity, will enhance recovery and b) which stroke survivors might be able to participate in pedalling.Methods/DesignParticipants (n = 24) will be up to 30 days since stroke onset, with unilateral weakness and unable to walk without assistance. This study will use a modified exercise bicycle fitted with a UniCam crank. All participants will give informed consent, then undergo baseline measurements, and then attempt to pedal. Those able to pedal will be entered into a single-centre, observer-blinded randomised controlled trial (RCT). All participants will receive routine rehabilitation. The experimental group will, in addition, pedal daily for up to ten minutes, for up to ten working days.Prognostic indicators, measured at baseline, will be: site of stroke lesion, trunk control, ability to ambulate, and severity of lower limb paresis.The primary outcome for the RCT is ability to voluntarily contract paretic lower limb muscle, measured by the Motricity Index. Secondary outcomes include ability to ambulate and timing of onset and offset of activity in antagonist muscle groups during pedalling, measured by EMG.DiscussionThis protocol is for a trial of a novel therapy intervention. Findings will establish whether there is sufficient evidence of benefit to justify proceeding with further research into clinical efficacy of upright pedalling exercise early after stroke. Information on potential prognostic indicators will suggest which stroke survivors could benefit from the intervention.Trial RegistrationISRCTN: ISRCTN45392701

The effects of lower limb training combined with hyperbaric oxygen on motor function in a paretic lower limb and on ability in the activities of daily living among hemiplegic stroke survivors

Objective To investigate the effects of lower limb training combined with hyperbaric oxygen on motor function in a paretic lower limb and on the ability in the activities of daily living （ADL） of hemiplegic stroke survivors. Methods A total of 297 hemiplegic stroke patients received routine interventions and then were randomly divided into 3 groups. The hyperbaric oxygen group accepted hyperbaric oxygen, the training group accepted lower limb training, and the treatment group accepted both hyperbaric oxygen and lower limb training. Evalnations were carried out pretreatment and 30 d post treatment to assess the function of the paretic lower limb and ADL ability with the Fugl-Meyer assessment （ FMA）, a modified Barthel index （MBI） , Berg＇s balance scale （BBS） and the timed up and go test （TUGT）. Results FMA, MBI, BBS and TUGT scores in all 3 groups improved significantly compared with pretreatment. On the 30th day post treatment, the scores in the treatment group were significantly better than in the other two groups. Conclusions Lower limb training combined with hyperbaric oxygen can significantly improve motor function in the paretic lower limbs of stroke patients and their ADL performance. Key words: Hemiplegia; Lower limb training; Hyperbaric oxygen; Lower limb function; Activities of daily living

Intrinsic Properties of the Knee Extensor Muscles After Subacute Stroke

Horstman AM, Gerrits KH, Beltman MJ, Koppe PA, Janssen, TW, de Haan A. Intrinsic properties of the knee extensor muscles after subacute stroke. Objective To characterize muscle properties of paretic lower-limb (PL) and nonparetic lower-limb (NL) knee extensors in patients with subacute stroke. Design Case-control study. Setting Rehabilitation center research laboratory. Participants Patients with subacute stroke (n=14) and able-bodied age-matched control subjects (n=12). Interventions Not applicable. Main Outcome Measures Half relaxation times (HRTs) and maximal rates of torque development (MRTDs) were assessed as indicators of contractile speed using both voluntary and electrically evoked contractions. Moreover, changes in torque were measured during a fatigue protocol (35 electrically evoked intermittent contractions; 1.5s on, 2s off) and recovery. Results No differences among groups were found for normalized MRTDs during electrically evoked contractions ( P=.117). However, during voluntary contractions both PLs (53% of control, P=.022) and NL (71% of control, P<.001) had significantly lower MRTD compared with control. Both PL (134% of control, P=.001) and NL (123% of control, P=.032) had significantly higher HRTs than control, indicating muscle slowing in patients with subacute stroke. PLs fatigued more and faster than control ( P=.011) and both PL and NL recovered slower ( P<.001). Conclusions The changes in HRTs and fatigue suggest adaptations in muscle properties toward slower, more fatigable muscle shortly after stroke. The inability to make use of contractile speed because of impaired neural activation seems the most limiting factor during the initial phase of torque development in PL. Thus, besides strengthening, muscle endurance and speed should also be addressed during rehabilitation.

Understanding Motor Impairment in the Paretic Lower Limb After a Stroke: A Review of the Literature

In addition to muscle weakness caused by injury to supraspinal centers, several mechanisms may contribute to motor impairment in the paretic lower limb following a stroke. Physiological changes in the paretic muscles and their motor units, passive or active restraint of agonist activation, and abnormal muscle activation patterns have been shown to occur after a stroke and to reduce muscle force generation. Other factors such as increased passive tone may impede agonist and antagonist muscle torque generation, while abnormal motor activation and altered motor control of muscles can produce abnormal gait patterns. Co-activation of opposing lower limb muscles contributes to joint stiffness and postural stability; abnormal co-activation in paretic lower limbs can lead to deficits in postural stabilization. Abnormal timing of muscle activation can also yield reduced muscle work output and, in turn, reduced limb function. When sensory deficits accompany muscle weakness, impaired processing of afferent signals may contribute to abnormal muscle activation, abnormal gait patterns, and abnormal responses to perturbation during gait and stance. This article reviews the impact of these various factors, individually and in combination, on impaired motor function in the paretic lower limb after a stroke.

P005 Effect of ankle-foot orthoses on functional balance, weight- bearing and relative contribution of the paretic lower limb to standing balance in stroke

P005 Effect of ankle-foot orthoses on functional balance, weight- bearing and relative contribution of the paretic lower limb to standing balance in stroke

Intrinsic muscle strength and voluntary activation of both lower limbs and functional performance after stroke

The objective of this study was to assess the nature of muscle weakness in both legs after stroke compared with able-bodied control individuals and to examine whether there is a relationship between the degree of muscle weakness and coactivation of knee extensors and flexors as well as voluntary activation capacity of knee extensors of both paretic and non-paretic legs and indices of functional performance. Maximal voluntary isometric torques of knee extensors (MVCe) and flexors (MVCf) were determined in 14 patients (bilaterally) and 12 able-bodied controls. Simultaneous measurements were made of torque and surface EMG from agonist and antagonist muscles. Coactivation was calculated. Supramaximal triplets were evoked with electrical stimulation to estimate maximal torque capacity and degree of voluntary activation of knee extensors. MVCs, activation and coactivation parameters were correlated to scores of seven functional performance tests. MVCe, MVCf and voluntary activation were lower in paretic lower limb (PL) compared with both non-paretic lower limb (NL) and control. Besides, all these parameters of NL were also lower than control. Electrically evoked torque capacity of knee extensors of PL was about 60% of both NL and control, which were not significantly different from each other. Strong significant correlations between strength, as well as voluntary activation, and functional performance were found. Coactivation did not correlate well with functional performance. Thus, whereas for NL activation failure can explain weakness, for PL both activation failure and reduced intrinsic torque capacity are responsible for the severe weakness. Activation capacity and muscle strength correlated strongly to functional performance, while coactivation did not.

Task-Oriented Intervention in Chronic Stroke

The objective of this study was to evaluate whether, after a task-oriented exercise program, the changes in clinical measures of balance and mobility were paralleled by changes in biomechanical parameters in subjects with chronic stroke. Ten stroke subjects took part in an 8-wk exercise program aimed at improving balance and mobility through various functional tasks. Subjects were evaluated before and after the exercise intervention. Clinical measures included the Berg Balance Scale and the Timed-Up-and-Go and laboratory measures included ground reaction forces and center of pressure displacement during four functional tasks. Stroke subjects showed significant improvements (P < 0.05) in the clinical measures after completing the exercise program. Significant improvements (P < 0.05) were also found in postural steadiness during tandem stance and stool touch and in force production through the paretic lower limb during sit-to-stand. This last result was strongly correlated (r = -0.93) with the improvements on the Timed-Up-and-Go after exercise intervention. In contrast, the increase in postural steadiness was poorly correlated with the improvements on the Berg Balance Scale. A task-oriented exercise program might improve both clinical and laboratory measures of balance and mobility in stroke subjects. However, several correlations between the changes in clinical and laboratory measures after exercise intervention were generally weak, indicating that these outcome measures assessed different components of improvements.

Bone-Density Changes After Stroke

It has been many years since bone loss and fracture risk were first recognized as serious complications of stroke. Hip fracture is associated with a substantial increase in morbidity and mortality for stroke survivors, and therefore, assessing and maintaining skeletal health after stroke should be an important clinical goal. Recent long-term, prospective studies have illustrated a highly nonuniform pattern of bone changes after stroke. In general, there is significant bone loss on the paretic side, which is greatest in those patients with the most severe functional deficits. In some patients, bone loss in the paretic arm during the first year after stroke is the equivalent of >20 yrs of bone loss in healthy individuals of comparable age. Bone density in the nonparetic upper limb can actually increase after stroke, consistent with an increase in habitual use of the nonparetic hand. Bone density in the paretic lower limb can decrease by >10% in <1 yr, with smaller decreases being typical for the nonparetic lower limb. Despite the recent increase in the number of prospective, longitudinal studies, important questions about bone changes after stroke remain unanswered. Longer-term studies quantifying bone loss for periods of >12 mos poststroke are needed to determine how long excess bone loss continues after stroke. Studies with more subjects and with more varied disability levels are needed to better understand the relationships between functional deficits and bone loss. New metrics are needed to quantify the intensity and duration of physical activity in the upper and lower limbs that are consistent with previous research on the role of mechanical stimuli in bone adaptation. Finally, an assessment of skeletal health and the factors that affect bone quantity and quality should be a standard component in the clinical management of all survivors of stroke.

Increased arterial stiffening and thickening in the paretic lower limb in patients with hemiparesis.

Atherosclerosis has two key components, thickening and stiffening of arterial wall. These parameters are quantified ultrasonographically by IMT (intima-media thickness) and PWV (pulse wave velocity). In the present study, we determined the FA IMT (IMT of the bilateral femoral artery) and PWV of femoral-ankle (PWV fa) and brachial-ankle (PWV ba) segments in order to examine whether the degree of atherosclerosis is different between paretic and non-paretic lower limbs in 24 patients with hemiparesis. The values of PWV fa, PWV ba and FA IMT were all significantly greater on the paretic than the non-paretic side. Furthermore, significant decreases in masses of muscle, bone and fat, determined by dual-energy X-ray absorptiometry, were observed in paretic lower limbs compared with the non-paretic side. PWV fa correlated significantly and negatively with muscle mass ( r =-0.488, P =0.0004) and tended to correlate negatively with BMC (bone mineral content; r =-0.264, P =0.069) when statistical analyses were performed with the paretic and non-paretic sides together. Multiple regression analysis elucidated that the muscle mass was associated significantly with PWV fa and PWV ba, independent of age, duration after cerebrovascular accident, gender, bone and fat mass and FA IMT. The muscle mass was still associated with increased PWV fa and PWV ba when multivariate analysis was conducted independently in the paretic and non-paretic sides. In summary, our results indicated that arterial thickening and stiffening were greater on the paretic than the non-paretic side and suggested that a decrease of muscle mass might be associated with increased arterial stiffening in the paretic lower limb.

Description of a new motor re-education programme for the paretic lower limb aimed at improving the mobility of stroke patients

Description of a new motor re-education programme for the paretic lower limb aimed at improving the mobility of stroke patients

Dynamic thigh muscle strength after auditory feedback training of body weight distribution in stroke patients

Thirty-six stroke patients who were or who were not given auditory feedback to enhance weightbearing on the paretic extremity when rising and sitting down took part in the study. The patients in the auditory feedback group (n = 18) loaded their paretic lower limb with 49% of their body weight (BW) when rising and with 48% BW when sitting down. In the control group, these loads were 44 and 43%, respectively. The torque of maximal voluntary concentric and eccentric knee extensions and knee flexions was measured using an isokinetic dynamometer at constant velocities of 30, 60, 120 and 240 deg/s (0.52, 1.05, 2.10 and 4.20 rad/s). The mean ratios of concentric peak torque of the paretic and non-paretic lower limbs were 60% in the auditory feedback group and 52% in the control group during slow (30 deg/s) knee extensions. The corresponding values for knee flexion were 42 and 39%, respectively. The differences between groups were not statistically significant, nor were there any significant differences in knee e...

Characterization of contralateral torques during static hip efforts in healthy subjects and subjects with hemiparesis.

Contralateral torques exerted at the hip were measured in healthy subjects and subjects with hemiparesis performing unilateral static hip efforts in abduction, adduction, flexion and extension, in a sitting position, at two torque levels. In general, the ipsilateral hip efforts were accompanied by mirrored contralateral torques in both groups of subjects. The directionality of these contralateral torques indicates that their action at the pelvis is mechanically opposite to the ipsilateral efforts, suggesting that they ensure the stabilization of the pelvis. In healthy subjects, analyses of variance showed no difference in the magnitude of the contralateral torques with regard to which limb was used to perform the task. However, a significant increase in magnitude was demonstrated in the contralateral torques concurrent with the increasing level of effort requested ipsilaterally. In hemiparetic subjects, when performing the tasks with their paretic limb, the magnitude of the contralateral torques was significantly increased in the non-paretic limb when compared with those measured in the paretic limb during non-paretic limb efforts. Based on the present results, a model of postural control is presented to explain the relationship between the ipsilateral and contralateral torques. Using this model, it is hypothesized that the increased contralateral torques observed in hemiparetic subjects when performing the tasks with their paretic limb is related to the weakness of the paretic muscles. The clinical importance of exercises used for the re-education of the paretic lower limb in this population, which consist of resisting the non-paretic hip movements in order to strengthen the paretic hip muscles, is discussed in light of these results.

Lower extremity weight bearing under various standing conditions in independently ambulatory patients with hemiparesis.

The purpose of this investigation was to determine if differences exist in weight bearing through the paretic and nonparetic lower extremities during various bilateral standing conditions. We used digital scales to measure weight bearing among 25 hemiparetic patients as they stood comfortably, as they alternately shifted as much weight as possible to each lower extremity, and as they alternately stood with each foot on a step. Patients bore significantly more weight (p less than .001) on their nonparetic than on their paretic lower limb during comfortable standing. They bore significantly more weight on their nonparetic extremity when shifting as much weight as possible to it than they did on their paretic extremity when shifting as much weight as possible to it (p less than .001). They bore significantly more weight (p less than .001) on the lower extremity that was not on the step during step standing. For patients comparable to those tested, standing with one lower limb on a 17-cm step should facilitate weight bearing through the contralateral lower limb.