Transcultural adaptation and validation of a Korea version of Pedi-IKDC questionnaire.

BACKGROUND: This study aimed to translate and transculturally adapt the English version of the Pedi-IKDC questionnaire into Korean and evaluate the psychometric properties of the Korean Pedi-IKDC questionnaire in terms of internal consistency, feasibility (floor and ceiling effect), construct validity, test-retest reliability, and factor analysis. METHODS: The original English version of the Pedi-IKDC questionnaire was translated and transculturally adapted into Korean according to established guidelines. A total of 239 patients aged 7-18 years who visited the hospital because of knee pain or discomfort were considered eligible for the study. These patients completed the Korean version of the Pedi-IKDC and Pediatric Quality of Life questionnaires (PedsQL). The correlation between the PedsQL and Pedi-IKDC questionnaires was assessed to confirm the validity of the questionnaire. To verify the validity of the Korean Pedi-IKDC questionnaire, internal consistency, feasibility, test-retest reliability, and construct validity were evaluated, and a factor analysis was performed. RESULTS: Internal consistency was found to be satisfactory in all subscales (Cronbach's alpha ≥ 0.7). The test-retest reliability was satisfactorily high for all subscales (Intraclass correlation coefficient: 0.81-0.84). A high correlation was observed between the total Pedi-IKDC score and the score on the physical-health subscale of child version of the PedsQL (Correlation coefficients: 0.720). There were no floor effects in all subscales, but ceiling effects were observed in four questions. Additionally, factor analysis suggested that the questionnaire could be divided into two subscales. CONCLUSION: The Korean version of the Pedi-IKDC questionnaire was successfully translated and transculturally adapted according to the established guidelines. The Korean Pedi-IKDC questionnaire has been proven reliable and valid.

Lower limb joint burden during walking in adolescent idiopathic scoliosis: investigation of mechanical work during walking.

BACKGROUND CONTEXT: Adolescent idiopathic scoliosis (AIS) is the most prevalent spinal deformity in adolescents. However, pathophysiology and long-term complications remain unclear. Characteristics of the mechanical work in AIS gait have not been well-studied. PURPOSE: This study aimed to elucidate the characteristics of mechanical work in AIS gait. STUDY DESIGN: Observational comparison study. PATIENT SAMPLE: Participants were composed of two groups: scoliosis group with 68 participants and a control group with 17 participants. OUTCOME MEASURES: Spinal deformity and coronal spinal balance in the scoliosis group were assessed with Cobb angle, coronal balance, and apical vertebra translation. Three-dimensional motion analysis during walking was conducted to calculate lower limb joint works and external work on the whole body's center of mass. METHODS: Lower limb joint work (JW) and external work on the whole body center of mass (CoM) were compared between the 2 groups with an independent t-test. Inter-limb and intra-limb comparisons of mechanical work were conducted with a paired t-test. The relationships between mechanical work and frontal trunk deformity were investigated in the scoliosis group. RESULTS: Walking speed and external work on whole body CoM did not differ between the two groups. Compared to the control group, the scoliosis group showed significantly larger JW on the convex and concave sides. CONCLUSION: The scoliosis group showed increased lower limb joint burden and limited trunk function for mechanical work during walking. Investigation of mechanical work during walking provides insight into the biomechanical characteristics of AIS. Therefore, future studies should be conducted to verify mechanical work characteristics which have relevance to the progression of spinal deformity and the development of lower limb complications in AIS.

Mott Cell Differentiation in Canine Multicentric B Cell Lymphoma with Cross-Lineage Rearrangement and Lineage Infidelity in a Dog.

Lymphoma is a severe condition characterized by the proliferation of neoplastic lymphoid cells. A 4-year-old female mongrel dog presented with solitary lymph node enlargement. Significant right prescapular lymphadenopathy and abdominal enlargement were observed during physical examination. A complete blood count revealed lymphocytosis, and a peripheral blood smear revealed lymphoblastosis and Mott cells. Fine needle aspiration cytology (FNAC) of the right prescapular lymph node revealed a predominant population of lymphoblasts and Mott cells. Based on the FNAC and blood smear results, the patient was diagnosed with leukemic state multicentric B-cell lymphoma with Mott cell differentiation. Subsequent PCR for antigen receptor rearrangement and flow cytometry revealed that the patient exhibited cross-lineage rearrangement (CLRA) and lineage infidelity (LI), respectively. CHOP-based chemotherapy was initiated, however, the patient's disease was progressive. The patient died three months after the initial presentation. Mott cell differentiation in canine B-cell lymphoma (MCL) has rarely been reported in the veterinary literature and seems to show an unusual clinical course. To the best of our knowledge, no reports of MCL with CLRA and LI exist. We report the clinical features, diagnosis, and treatment of MCL with CLRA and LI.

Change of gait after unilateral vestibular neuritis: a prospective longitudinal observation study.

Although symptoms of unilateral vestibular neuritis (uVN) resolve spontaneously within several weeks, recovery of gait function has unclearness in gait parameter changes and mediolateral stability improvements. In addition, prospective longitudinal studies on gait parameters after uVN are lacking. This study was conducted to reveal longitudinal change of gait function after acute uVN and to help the precise rehabilitation planning. Twenty three participants with uVN and 20 controls were included. 3D gait analyses were conducted three times after uVN onset at monthly intervals. From the gait analysis data, spatio-temporal parameters, inclination angle (IA) representing the relationship between center of mass (CoM) and center of pressure (CoP) in the frontal plane, and IA variability were obtained. Time effects on gait metrics were tested. Walking speed of participants with uVN improved significantly between the 1st and 3rd tests, but they were not significantly different to that of control, even in the 1st test. The step width of participants with uVN was significantly larger than that of control in the 1st test and improved significantly in the 2nd test. Variability of IA in affected side was significantly larger than that in controls in the 1st test and improved significantly in the 3rd test compared to the 1st test. Improvement of overall gait function and mediolateral stability during gait continued after acute stage of uVN (two months from onset in this study). Rehabilitation intervention should be continued after the acute stage of uVN to enhance appropriate adaptation in gait.

Inter-limb difference of mechanical work in limb length discrepancy.

BACKGROUND: Limb length discrepancy (LLD) is common and is associated with musculoskeletal disorders. Selection of adaptation strategies, the side more susceptible to complications, and the relationships between LLD magnitude and musculoskeletal complications are unclear. To elucidate these ambiguities, studies on gait parameters in LLD have been conducted. However, studies on inter-limb difference of mechanical work in LLD are rare. RESEARCH QUESTION: To investigate whether inter-limb differences in mechanical work in LLD and the relationship between LLD magnitude and mechanical work performed by each lower limb are significant. METHODS: Thirty-seven participants with LLD and without neuromuscular disorders disturbing normal gait were included. Three-dimensional motion analysis was conducted to obtain data on mechanical work, including joint work and the individual limb method (ILM) work. Mechanical work performed by the longer and shorter limbs was compared using paired t-test. Relationships between LLD and mechanical work were investigated using correlation and multiple regression analyses in both limbs. Eighteen participants had LLD > 20 mm, large group (LG), and 19 had LLD < 20 mm, small group (SG). Data exploration was conducted for the effect of LLD severity (LG vs. SG) on mechanical work. RESULTS: LLD showed significant inter-limb difference of mechanical work and negative correlations with positive and negative ILM work performed by the shorter limb. The shorter limb in SG performed significantly larger positive ILM work than the longer limb, whereas the longer limb in LG performed significantly larger negative ILM work than the shorter limb. SIGNIFICANCE: LLD showed inter-limb difference of ILM work and different adaptation strategies between LG and SG. These differences attribute to the decrease in ILM work performed by the shorter limb with the increase in LLD. Mechanical work including ILM work should be included in future studies to prevent complications and development of treatment methods for LLD.

Asymmetry and Variability Should Be Included in the Assessment of Gait Function in Poststroke Hemiplegia With Independent Ambulation During Early Rehabilitation.

OBJECTIVE: To extract independent features from spatiotemporal data of poststroke gait. DESIGN: Retrospective observational study. SETTING: Motion analysis laboratory in the rehabilitation department of a university hospital. PARTICIPANTS: Convenience sample from inpatients in subacute recovery stage post stroke. Of 98 patients post stroke who underwent gait assessment, 69 patients post stroke were included in the data analysis (N=69). They could walk more than 10 m without personal assist or assistive devices. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Spatiotemporal parameters during level walking and their asymmetry and variability were obtained by insole foot pressure measurement system. RESULTS: Of independent components extracted by principal component analysis, 3 independent components explained 81.9% of total variance of spatiotemporal poststroke gait data. The first component has associations with walking speed and proportion of double support phase, and it explains 46.6% of total variance. The second component has association with temporal asymmetry, and it explains 21.1% of total variance. The third component has association with temporal variability, and it explains 14.2% of total variance. Principal component scores did not show significant differences between stroke types and among stroke lesions. CONCLUSIONS: Temporal asymmetry and variability should be included in the assessment of poststroke gait during early rehabilitation. They are independent of each other and provide characteristics of poststroke gait that are independent to the walking speed. They are helpful for rehabilitation planning and developing treatment strategy in poststroke gait rehabilitation.

Change in Center of Pressure Progression in the Foot Provides Clues for Functional Improvement of the More Affected Lower Limb During Post-stroke Gait Rehabilitation.

OBJECTIVE: The aim of this study was to determine the clinical significance of the anterior-posterior displacement of the center of pressure in the foot (apCoP) in post-stroke gait rehabilitation. DESIGN: This observational study was conducted in a tertiary hospital. Forty-two subacute post-stroke patients were included. The apCoP was measured twice with a wearable insole foot pressure measurement system, time interval more than 7 days. The results were compared between the first and second tests. The relationship between apCoP changes and spatiotemporal parameter changes were investigated. RESULTS: The apCoP increased significantly between tests. The change in walking speed was significantly predicted by the change in the apCoP on the less affected side. The change in asymmetry of the single support phase was significantly correlated with the change in the apCoP on the more affected side. CONCLUSION: The change in apCoP provides information about the restoration of body support, body forward progression control, and propulsion in the more affected lower limb during early post-stroke rehabilitation. The apCoP can be a useful parameter for the monitoring of functional changes in the more affected lower limb during post-stroke gait rehabilitation.

Validation of FRIEND and ACSM Equations for Cardiorespiratory Fitness: Comparison to Direct Measurement in CAD Patients.

The regression equation of the American College of Sports Medicine (ACSM) was a preferred method for estimating maximal oxygen consumption (VO2max). Recently, a more precise equation from the fitness registry and the importance of exercise national database (FRIEND) for healthy people was developed. This study compared VO2max estimated by the ACSM and FRIEND equations to VO2max directly measured in coronary artery disease (CAD) patients. Overall, 293 CAD patients who participated in cardiac rehabilitation between June 2015 and December 2018 were analyzed. Directly measured VO2max values were compared to the ACSM and FRIEND equations. The directly measured VO2max was significantly different from the estimated VO2max by ACSM equation (24.16 vs. 28.7 mL/kg/min, p < 0.001), which was overestimated by 20% in men and 16% in women. However, there was no statistically significant difference between the directly measured VO2max and the estimated VO2max by the FRIEND equation. (24.16 vs. 24.15 mL/kg/min, p = 0.986). In CAD patients, the estimated VO2max from the ACSM equation was significantly higher than the directly measured VO2max. In addition, estimated cardiorespiratory fitness (CRF) by the FRIEND equation showed similar results with directly measured CRF. As a result, the FRIEND equation can predict CRF more accurately than the ACSM.

Handgrip Strength as a Predictor of Exercise Capacity in Coronary Heart Disease.

PURPOSE: A recent study has shown that quadriceps strength can be used to predict the level of exercise capacity in patients with coronary heart disease. We investigated whether the relationship between muscular strength and exercise capacity is also observed with handgrip strength (HGS). METHODS: We studied 443 participants (61.8 ± 11.2 yr; 78% male) who underwent coronary intervention and participated in cardiac rehabilitation between 2015 and 2018. Logistic regression was used to assess the relationship between various clinical measures (HGS, age, sex, etc) with the distance walked on a 6-minute walk test (6MWT) and maximal oxygen uptake ((Equation is included in full-text article.)O2max). RESULTS: Handgrip strength was related to distance walked on the 6MWT (r = 0.435, P < .001). It was the only predictor of all exercise capacity categories, and one of the strongest predictors of each exercise capacity category. An HGS of 26% of body weight predicted an achievement of a 200-m walk on the 6MWT (positive predictive value = 0.95). However, HGS <36% of body weight predicted that 500 m could not be done in 6 min (negative predictive value = 0.97). This trend was also observed in the subgroups in which (Equation is included in full-text article.)O2max was measured. CONCLUSION: This study demonstrates that HGS is associated with exercise capacity in coronary heart disease and can be used to predict the level of exercise capacity. These findings may contribute to setting the recommended level of daily activity as well as the level of cardiac rehabilitation in coronary heart disease.

Influences of elbow, shoulder, trunk motion and temporospatial parameters on arm swing asymmetry of Parkinson's disease during walking.

Arm swing asymmetry is commonly observed in early Parkinson's disease (PD) and has been found to be useful for early diagnosis. However, there are uncertainties about the nature of its relationships with gait parameters, especially shoulder and elbow motions. Therefore, this study explored how these relationships are different between PD and controls. Forty one early PD and 23 controls were included. Participants walked at self-selected speed for 3D motion analysis. Arm swing at the wrist (AS), temporospatial parameters and kinematics in elbow, shoulder and trunk were obtained. Amplitudes and asymmetries of these variables were compared between PD and control groups. PD group showed increased AS asymmetry, compared to controls. Multiple hierarchical regression analysis on AS asymmetry was conducted in order to investigate how PD influences on the relationship between AS asymmetry and other variables. In pooled data (PD and control group), asymmetries in elbow and shoulder range of motion (RoM) were significant predictors for AS asymmetry but walking speed and asymmetries in temporospatial parameters were not significant. Group effect (PD effect) was significantly mediated by only elbow RoM asymmetry. Interaction between group and elbow RoM asymmetry was statistically significant, indicating that group was an effect modifier for elbow RoM asymmetry effect on AS asymmetry. Conclusively, arm swing asymmetry measured at the wrist represents the involvement of PD effect on the unilateral and distal upper limb in early stage. These findings are helpful for future researches related to clinical applications and mechanisms of arm swing asymmetry in PD.

Anterior-posterior displacement of center of pressure measured by insole foot pressure measurement system in subacute recovery stage of post-stroke hemiplegia.

BACKGROUND: Anterior-posterior displacement of center of pressure (AP_CoP) reflects stance limb function. However, AP_CoP's clinical applicability in post-stroke hemiplegia is unclear. OBJECTIVE: To investigate the clinical usefulness of parameters from AP_CoP in subacute stage post-stroke hemiplegia, their relationships with usage of gait aid, functional ambulatory category, and spatial-temporal parameters were tested. METHODS: Nineteen participants with post-stroke hemiplegia were included in gait with aid group. Twenty one participants were included in gait with independence group. Twenty one participants were included in control group. Insole foot pressure measurement system was used to measure AP_CoP and spatial-temporal parameters. Effects of gait aid usage and functional ambulatory category on AP_CoP were tested with ANOVA. Relationships between AP_CoP and temporo-spatial parameters were investigated with correlation and linear regression analysis. RESULTS: AP_CoP parameters were shorter in gait with aid group than gait with independence group. With better functional ambulatory category, AP_CoP were longer. AP_CoP showed positive relationship with walking speed. AP_CoP in more affected side showed positive relationship with symmetry of single support phase proportion. AP_CoP showed positive relationship with stride length. CONCLUSIONS: AP_CoP reflects overall gait function, impairments in more affected side and adaptation in less affected side in subacute recovery stage of post-stroke hemiplegia. It can be used as a clinically significant parameter for gait rehabilitation.

Examining impairment of adaptive compensation for stabilizing motor repetitions in stroke survivors.

The hand, one of the most versatile but mechanically redundant parts of the human body, suffers more and longer than other body parts after stroke. One of the rehabilitation paradigms, task-oriented rehabilitation, encourages motor repeatability, the ability to produce similar motor performance over repetitions through compensatory strategies while taking advantage of the motor system's redundancy. The previous studies showed that stroke survivors inconsistently performed a given motor task with limited motor solutions. We hypothesized that stroke survivors would exhibit deficits in motor repeatability and adaptive compensation compared to healthy controls in during repetitive force-pulse (RFP) production tasks using multiple fingers. Seventeen hemiparetic stroke survivors and seven healthy controls were asked to repeatedly press force sensors as fast as possible using the four fingers of each hand. The hierarchical variability decomposition model was employed to compute motor repeatability and adaptive compensation across finger-force impulses, respectively. Stroke survivors showed decreased repeatability and adaptive compensation of force impulses between individual fingers as compared to the control (p < 0.05). The stroke survivors also showed decreased pulse frequency and greater peak-to-peak time variance than the control (p < 0.05). Force-related variables, such as mean peak force and peak force interval variability, demonstrated no significant difference between groups. Our findings indicate that stroke-induced brain injury negatively affects their ability to exploit their redundant or abundant motor system in an RFP task.

Individual joint contribution to body weight support in the affected lower limb during walking in post-stroke hemiplegia.

OBJECTIVE: Patients with post-stroke hemiplegia have difficulty with body weight support during walking. However, it is unclear which intra-limb strategy for body weight support tends to predominate, and how the intra-limb strategy is related to gait function. Support moment and individual joint contribution to support moment are the parameters that reflect intra-limb strategy for body weight supporting. The aim of this study was to test whether support moment and individual joint contributions differed between post-stroke subjects with different gait function. METHOD: Laboratory gait analysis was performed for 14 non-hemiplegic elderly (NE) and 12 post-stroke hemiplegic elderly walking without cane (HNC) and 11 walking with a cane (HWC). Data were obtained for the vertical ground reaction force (vGRF) curve, 1st peak and 2nd peak of vGRF and corresponding temporal occurrences. Support moment (Ms) was numerical sum of hip extension, knee extension, and ankle plantar flexion moment. Individual joint contribution was calculated as the ratio of each joint moment to support moment. At temporal occurrences of vGRF peaks, Ms and individual joint contribution to Ms were calculated. Ms and individual joint contribution to Ms were compared among NE, HNC and HWC groups. Each subject's characteristics of individual joint contribution to Ms were explored. RESULTS: At the 1st peak of vGRF, support moments were similar among the three groups. However, the hip contributions were significantly greater in the NE group than in the other two groups, the ankle contributions were significantly greater in the HNC group than in the NE group. Notably, some of the subjects with post-stroke hemiplegia showed atypical characteristics that did not correspond to the group characteristics. CONCLUSION: Observing support moment and individual joint contribution is helpful to ascertain not only group characteristics, but also individual characteristics of intra-limb strategy for weight support in patients with post-stroke hemiplegia.

[A Case of Early Gastric Cancer with Nodular Tumor-like Scalp Metastasis].

Many neoplasms, including lung cancer, breast cancer, melanoma, and gastrointestinal tract malignancy, possess potential for skin metastasis. Skin metastases can represent the first presentation of such malignancies and may be observed incidentally during routine exam. Skin metastases from gastric adenocarcinoma are uncommon, with a prevalence rate of 0.04-0.8%. Cutaneous metastases from gastric cancer are generally observed as the initial symptom of advanced gastric cancer. Early detection and treatment can increase patient survival. A 42-year-old woman visited our department with nodule about 1 cm in size on the right frontal scalp noticed incidentally after laparoscopy-assisted distal gastrectomy and adjuvant systemic chemo-therapy for early gastric cancer about 16 months prior. The patient was diagnosed with skin metastasis from gastric adenocarcinoma. Complete excision of the skin lesion and additional chemotherapy were performed. Herein, we report a case of nodular tumor-like scalp metastasis from early gastric cancer with a brief review of the literature.

Subtasks affecting step-length asymmetry in post-stroke hemiparetic walking.

This study was performed to investigate whether components from trunk progression (TP) and step length were related to step length asymmetry in walking in patients with hemiparesis. Gait analysis was performed for participants with hemiparesis and healthy controls. The distance between the pelvis and foot in the anterior-posterior axis was calculated at initial-contact. Step length was partitioned into anterior foot placement (AFP) and posterior foot placement (PFP). TP was partitioned into anterior trunk progression (ATP) and posterior trunk progression (PTP). The TP pattern and step length pattern were defined to represent intra-TP and intra-step spatial balance, respectively. Of 29 participants with hemiparesis, nine participants showed longer paretic step length, eight participants showed symmetric step length, and 12 participants showed shorter paretic step length. For the hemiparesis group, linear regression analysis showed that ATP asymmetry, AFP asymmetry, and TP patterns had significant predictability regarding step length asymmetry. Prolonged paretic ATP and shortened paretic AFP was the predominant pattern in the hemiparesis group, even in participants with symmetric step length. However, some participants showed same direction of ATP and AFP asymmetry. These findings indicate the following: (1) ATP asymmetries should be observed to determine individual characteristics of step length asymmetry, and (2) TP patterns can provide complementary information for non-paretic limb compensation.

Deficits in motor abilities for multi-finger force control in hemiparetic stroke survivors.

The ability to control redundant motor effectors is one of hallmarks in human motor control, and the topic has been studied extensively over several decades since the initial inquiries proposed by Nicholi Bernstein. However, our understanding of the influence of stroke on the control of redundant motor systems is very limited. This study aimed to investigate the effect of stroke-related constraints on multi-finger force control abilities in a visuomotor task. Impaired (IH) and less-impaired hands (LH) of 19 hemiparetic stroke survivors and 19 age-matched control subjects were examined. Each hand repeatedly produced isometric forces to match a target force of 5 N shown on a computer screen using all four fingers. The hierarchical variability decomposition (HVD) model was used to separate force-matching errors (motor performance) into task-relevant measures (accuracy, steadiness, and reproducibility). Task-irrelevant sources of variability in individual finger force profiles within and between trials (flexibility and multiformity) were also quantified. The IH in the stroke survivors showed deficits in motor performance attributed mainly to lower accuracy and reproducibility as compared to control hands (p < 0.05). The LH in stroke survivors showed lower reproducibility and both hands in stroke also had higher multiformity than the control hands (p < 0.05). The findings from our HVD model suggest that accuracy, reproducibility, and multiformity were mainly impaired during force-matching task in the stroke survivors. The specific motor deficits identified through the HVD model with the new conceptual framework may be considered as critical factors for scientific investigation on stroke and evidence-based rehabilitation of this population.

Asymptomatic Gastric Band Erosion Detected during Routine Gastroduodenoscopy.

The incidence of gastric band erosion has decreased to 1%. Gastric band erosion can manifest with various clinical symptoms, although some patients remain asymptomatic. We present a case of a mostly asymptomatic patient who was diagnosed with gastric band erosion during a routine health check-up. A 32-year-old man without any underlying diseases except for non-alcoholic fatty liver underwent laparoscopic adjustable gastric band surgery in 2010. He had no significant complications postoperatively. He underwent routine health check-ups with near-normal gastroduodenoscopic findings through 2014. However, in 2015, routine gastroduodenoscopy showed that the gastric band had eroded into the stomach. His gastric band was removed laparoscopically, and the remaining gastric ulcer perforation was repaired using an omental patch. Due to the early diagnosis, the infection was not serious. The patient was discharged on postoperative day 3 with oral antibiotics. This patient was fortunately diagnosed early by virtue of a routine health check-up; thus, eliminating the possibility of serious complications.

Difference of motor overflow depending on the impaired or unimpaired hand in stroke patients.

The aim of this study was to investigate the patterns of contralateral motor overflow (i.e. mirror movement) between the homologous body parts on the right and left side, in stroke patients during single-finger and multi-finger maximum force production tasks. Forty subjects, including stroke (n=20) and normal subjects (n=20), participated in this study. The stroke subjects maximally pressed force sensors with their fingers in a flexed position using a single (index, middle, ring, or little) or all fingers (all 4 fingers) using the impaired (IH) or unimpaired (UIH) hand, while the non-patient subjects used their right hands for the same tasks. The maximal voluntary forces in the ipsilateral and unintended pressing forces of each contralateral finger were recorded during the tasks. The magnitude of motor overflow to the contralateral side was calculated using the index of contralateral independence (CI). During the single finger tasks, the finger CI was significantly decreased in the UIH (91%) compared with that in the IH (99%) or normal hands (99%). Likewise, the multiple finger tasks showed that the CI was significantly lower in the UIH (84%) compared with that in the IH (96%) or normal hands (99%). However, the maximal forces were significantly lower in the IH relative to those in the UIH and normal hands. These data demonstrate that stroke patients have greater motor overflow from the UIH to the IH.

Comparing self-selected speed walking of the elderly with self-selected slow, moderate, and fast speed walking of young adults.

OBJECTIVE: To find the characteristics of elderly gait, we compared the elderly walking at a moderate speed with the young adult walking at a slow, moderate, and fast speed. METHODS: 3D gait analysis was performed on 15 elderly and 15 young adults. Temporo-spatial, kinematic, and kinetic parameters were obtained. Self-selected moderate speed of the elderly walking was compared with self-selected varying speed of the young adults walking. RESULTS: The elderly walked at slower speeds and had shorter step length, but showed similar cadences compared to the young adults. These results remained identical even after the normalization with height. The kinematic and the kinetic graph patterns did not show specific differences between the elderly and the young subjects. Ankle plantarflexion (APF) motion was prominently decreased in the elderly subjects. Hip flexion (HF) motion remained within similar range for the young adults'. HF moment and power were similar with the young adults', but APF power and hip extension power were decreased in the elderly subjects'. CONCLUSION: A decreased APF motion and power were thought to be specific findings in the elderly walking. The preservation of HF motion and power could be considered a compensation mechanism or a modified neuromuscular pattern in the elderly. The characteristics of the elderly walking should be taken into account when planning rehabilitation strategies of elderly gait training and for future studies on the elderly population.

The effect of stroke on motor selectivity for force control in single- and multi-finger force production tasks.

BACKGROUND: The stroke patients have difficulties in both voluntary muscle contraction and individual movements. However, there is a lack of quantitative analysis focusing on decreased finger control in stroke patients. OBJECTIVES: The purpose of the study was to identify the changes in motor selectivity in stroke patients during a finger force production task. METHODS: Fifteen stroke patients and fifteen control subjects were asked to perform maximum voluntary force (MVF) production during single- and multi-finger force tasks. Finger interaction indices such as force independence (FI) and force sharing deviation (FSD) were analyzed using measured individual finger forces. RESULTS: MVF analysis in the impaired hand of stroke patients showed that they produced 31% or 41% lower force than their unimpaired hand or the control hand, respectively. For the finger interaction indices, the stroke patients' impaired hand had lower FI and higher FSD than their unimpaired hand or the normal subjects' hand. CONCLUSION: The lower FI and higher FSD show that stroke patients have a limited ability to produce force independently and to synchronize produced multi-finger force, respectively. These results have a negative impact on the selectivity of their motor control. In terms of rehabilitation, we expect that the finger interaction indices used in the present study can quantify motor selectivity in the damaged central nervous system.