Reza Salehi

Reliability of center of pressure measures of postural stability in healthy older adults: Effects of postural task difficulty and cognitive load

Postural instability is a major risk factor of falling in the elderly. It is well documented that postural control may decline while performing a concurrent cognitive task and this effect increases with age. Despite the extensive use of dual tasking in balance assessment protocols, a lack of sufficient reliability information is evident. This study determines the reliability of the postural stability measures in older adults, assessed under single and dual-task conditions and different levels of postural difficulty. Sixteen older adults completed quiet stance postural measurements at three levels of difficulty (rigid surface-eyes open, rigid surface-eyes closed, and foam surface-eyes closed), with or without performing a concurrent backward counting task, in two sessions 1 week apart. Force plate data was used to calculate center of pressure (COP) parameters including mean velocity, phase plane portrait, area (95% confidence ellipse), standard deviation (SD) of amplitude, and SD of velocity. Intraclass correlation coefficient (ICC), standard error of measurement (SEM), coefficient of variation (CV), and minimal metrically detectable change (MMDC) were calculated for each COP measure in all test conditions. Mean velocity, total phase plane, phase plane in ML direction, and SD of velocity in ML direction were the most reliable COP measures across all test conditions. ICC values were consistently higher in ML direction compared with AP direction. In general, velocity-related COP measures in ML direction showed to be highly reliable. Further research may explore the predictive and evaluative value of these COP parameters.

Persian translation and validation of the Kujala Patellofemoral Scale in patients with patellofemoral pain syndrome

Purpose: To culturally translate and validate the Persian version of Kujala Patellofemoral Scale (KPS) and evaluate the test-retest reliability, internal consistency, construct validity and ceiling or floor effects of this instrument in patients with patellofemoral pain syndrome (PFPS). Method: After standard forward and backward translations, 100 patients with PFPS completed the Persian versions of the KPS and Short-Form 36 Health Survey (SF-36) in the first visit. With time interval of 2–3 days after the first visit, 47 patients filled out the KPS in the second visit. Test-retest reliability and internal consistency were assessed using intraclass correlation coefficient (ICC2,1) with 95% confidence interval (95% CI) and Cronbach’s α coefficient, respectively. The Spearman’s rank correlation (rs) was used to assess the correlations between the Persian KPS and SF-36 subscales. Results: The acceptable level of ICC >0.70 (ICC = 0.96, 95% CI = 0.93–0.98) and Cronbach’s α coefficient >0.70 (α = 0.81) was obtained for the Persian KPS. There were low to moderate correlations (rs = 0.25–0.60, p < .01) between the Persian KPS and Persian SF-36 subscales of mental and physical health components. However, correlations between the Persian KPS and SF-36 physical components were higher than correlations between the Persian KPS and SF-36 mental components. No ceiling and floor effects were seen for the Persian KPS. Conclusions: The Persian version of KPS is a reliable and valid outcome measure of disability and seems to be a suitable instrument for use in clinical practice of Iranian patients with chronic PFPS. Implications for Rehabilitation The results on psychometric properties of the Persian Kujala Patellofemoral Scale are comparable with three validated versions obtained for the Finnish, Turkish and Chinese populations. Persian version of the Kujala Patellofemoral Scale has acceptable reliability/validity and now can be used in “clinical” and “research” settings of Iranian patients with chronic patellofemoral pain syndrome.

Attentional demands of postural control during single leg stance in patients with anterior cruciate ligament reconstruction.

The aim of this study was to investigate the amount of attention demands of postural control in patients with anterior cruciate ligament-reconstruction (ACL-R), by comparing the pattern of posture-cognition interaction between two groups of ACL-R patients (n=25) and healthy matched controls (n=25). All participants were examined during single-leg stance on a balance board under both single- and dual-task conditions in 4 dynamic balance tests. These tests were standing on the injured and uninjured legs with straight or flexed knees. The corresponding dominant and non-dominant legs of healthy group were considered as controls. Contact frequency and contact time were acquired as a measure of postural performance. Cognitive performance was assessed by counting the number of errors in a silent backward digit span task. The results of analysis of variance showed a significant higher contact frequency and longer contact time in patients with ACL-R compared to healthy matched controls (p<0.02). Moreover, the ACL-R patients showed a significantly higher contact frequency and longer contact time during dual-task compared to single-task conditions (p<0.01). This pattern of posture-cognition interference was not observed in the healthy control group. In conclusion, patients who had undergone ACL-R surgery demonstrated poorer balance stability during single-leg stance than healthy controls. Also, simultaneous execution of the cognitive task during standing caused a significant deterioration in postural stability which indicates decreased automaticity (increased attention demanding) of postural control in patients with ACL-R compared to healthy controls.

Reliability and validity of the Persian lower extremity functional scale (LEFS) in a heterogeneous sample of outpatients with lower limb musculoskeletal disorders

Abstract Purpose: The aim was to culturally translate and validate the Persian lower extremity functional scale (LEFS) in a heterogeneous sample of outpatients with lower extremity musculoskeletal disorders (n = 304). Method: This is a prospective methodological study. After a standard forward–backward translation, psychometric properties were assessed in terms of test–retest reliability, internal consistency, construct validity, dimensionality, and ceiling or floor effects. Results: The acceptable level of intraclass correlation coefficient >0.70 and Cronbach’s alpha coefficient >0.70 was obtained for the Persian LEFS. Correlations between Persian LEFS and Short-Form 36 Health Survey (SF-36) subscales of Physical Health component (rs range = 0.38–0.78) were higher than correlations between Persian LEFS and SF-36 subscales of Mental Health component (rs range = 0.15–0.39). A corrected item--total correlation of >0.40 (Spearmans rho) was obtained for all items of the Persian LEFS. Horn’s parallel analysis detected a total of two factors. No ceiling or floor effects were detected for the Persian LEFS. Conclusions: The Persian version of the LEFS is a reliable and valid instrument that can be used to measure functional status in Persian-speaking patients with different musculoskeletal disorders of the lower extremity. Implications for Rehabilitation The Persian lower extremity functional scale (LEFS) is a reliable, internally consistent and valid instrument, with no ceiling or floor effects, to determine functional status of heterogeneous patients with musculoskeletal disorders of the lower extremity. The Persian version of the LEFS can be used in clinical and research settings to measure function in Iranian patients with different musculoskeletal disorders of the lower extremity.

The effects of muscle fatigue on dynamic standing balance in people with and without patellofemoral pain syndrome.

The aim was to examine the effects of muscle fatigue of knee extensor and hip abductor muscles on dynamic standing balance of patients with patellofemoral pain syndrome (PFPS) compared to their healthy matched controls. Thirty participants (15 with PFPS, 15 controls) were recruited. Isolated muscle fatigue of two muscles was induced isokinetically in three separate sessions (one practice and two testing sessions) with a rest interval of at least 72h. In each testing session, fatigue protocol of only one muscle group was performed for the both legs with a rest time of 30min. After determining peak torque, participants were encouraged to perform continuous maximal concentric-eccentric contraction of the target muscle until the torque output dropped below 50% of peak value for 3 consecutive repetitions. Immediately after the completion of the fatigue protocol, balance testing of participants was undertaken during single leg standing using the Biodex stability system. Balance stability measures included the overall, anteroposterior and mediolateral stability indices (OSI, APSI and MLSI, respectively). Patients exhibited decreased balance stability in the sagittal plane (higher APSI) when compared to controls. Isolated muscle fatigue of the knee extensors and hip abductors reduced balance stability in both study groups. Fatigue of hip abductors was associated with greater balance instability (higher OSI and APSI) than fatigue of knee extensors.

The Persian Version of Community Integration Questionnaire in persons with multiple sclerosis: translation, reliability, validity, and factor analysis

Purpose: To culturally translate and validate the Community Integration Questionnaire (CIQ) in persons with multiple sclerosis (MS). Methods: After a forward–backward translation, 105 persons with MS completed the Persian versions of the CIQ and MS Quality of Life (MSQOL) questionnaires in the first visit. The CIQ was re-administered to a sample of 45 persons with MS 7–10 days after the first session. Test–retest reliability and internal consistency were assessed using intraclass correlation coefficient (ICC) and Cronbach’s α coefficient, respectively. Construct validity was assessed by measuring associations between subscales of the Persian CIQ (including Home Integration (HI), Social Integration (SI), and Productivity (P)) and MSQOL (including Physical and Mental Components). Dimensionality was assessed through two methods of corrected item-subscale correlation and factor analysis. Results: The acceptable level of test–retest reliability (ICC ≥0.70) was obtained for the Persian CIQ. However, Cronbach’s α coefficient of ≥0.70 was only seen for the HI. The correlations between the Persian CIQ and the Physical MSQOL were higher than those of Persian CIQ and the Mental MSQOL. The corrected item-subscale Spearman’s correlation coefficient of 0.40 was exceeded by most items of the HI and 2 items of P. A total of four factors were detected and similar to the results of item-subscale correlation, the most variability was seen for the items of SI which loaded on different factors. Conclusions: Persian CIQ seems to be a reliable and valid instrument for monitoring the level of community integration following rehabilitation in persons with MS. Some modifications need to be made in the SI of the Persian CIQ to improve extraction of information regarding community integration of persons with MS. Implications for Rehabilitation The results on psychometric properties of the Persian Community Integration Questionnaire (CIQ) are comparable with the English and Spanish versions. Persian version of the CIQ appears to be a reliable and valid instrument to assess community integration in “clinical” and “research” settings of Persian-speaking Iranians with definite diagnosis of multiple sclerosis (MS).

Validity and reliability of Persian version of the specific Nordic questionnaire in Iranian industrial workers

BACKGROUND Nordic is one of the most popular questionnaires for evaluating Work-related Musculoskeletal Disorders (WMSDs), but no studies have been reported on the reliability and validity of this questionnaire in Iran. OBJECTIVE The aim of this study was translation, cross-cultural adaptation and validation of the Persian version of the Specific Nordic questionnaire (SNQ), and evaluation of the reliability of this questionnaire for the assessment of WMSDs in Iranian industrial workers. METHODS The SNQ was completed by 122 Iranian industrial workers with lumbar or knee musculoskeletal disorders to assess the reliability and construct validity. The validity was assessed by knee injury and Osteoarthritis Outcome Score (KOOS) and Oswestry Disability Index (ODI) questionnaires. Reliability was assessed by a test-retest procedure for 60 patients with 7-days interval. RESULTS There was significant positive correlation between KSNQ and KOOS pain (r = 0.71, p < 0.05) and the KSNQ and KOOS QOL (r = 0.72, p < 0.05). There was High Pearson correlation between LSNQ and ODI (r = 0.77, p < 0.05). Both lumbar and knee SNQ had a high Kappa coefficient correlation (0.83-1 for KSNQ and 0.63-1 for LSNQ). CONCLUSIONS The Persian version of the SNQ is a reliable and valid instrument to be used for the assessment of WMSDs in Iranian industrial workers.

Responsiveness of selected outcome measures of participation restriction and quality of life in patients with multiple sclerosis

Abstract Purpose: To evaluate the responsiveness of two outcome measures of participation restriction [as measured by the Community Integration Questionnaire (CIQ)] and quality of life [as measured by the Multiple Sclerosis Quality of Life (MSQOL)] following a physiotherapy intervention in patients with multiple sclerosis (MS). Method: A sample of 265 patients completed both instruments first at the time of initial visit and then after 4–6 weeks physiotherapy. In addition, patients were asked to complete the 7-point global rating scale as an external criterion of change at the post-intervention time. The responsiveness was evaluated using the receiver operating characteristics (ROC) method and the correlation analysis. Two useful statistics were area under the ROC curve (AUC) and the minimally clinically important difference (MCID). The AUC and correlation coefficient greater than 0.70 were considered as acceptable responsiveness. Results: The CIQ achieved the acceptable responsiveness with an AUC of 0.81. However, the AUCs of 0.61 and 0.66 were obtained for the MSQOL physical and mental, respectively. Moreover, good correlation coefficient was obtained for the CIQ (Gamma = 0.76) while fair correlations of 0.28 and 0.33 were obtained for the MSQOL physical and mental, respectively. The MCIDs were approximately 0.50, 1.5 and 2.5 points for the CIQ, MSQOL physical and mental, respectively. Conclusions: In contrast to the MSQOL, the CIQ was responsive outcome measure in detecting changes in participation restriction of patients with MS. Moreover, the MCID values obtained in this study will help the clinicians and researchers to determine if a patient with MS has experienced a true change following physiotherapy intervention. Implications for Rehabilitation The results provide valuable information regarding to the ability of two outcome measures (i.e. the CIQ and MSQOL) to detect treatment effects in patients with MS. In contrast to the MSQOL, the CIQ is a responsive measure to changes in participation restriction due to physiotherapy. A patient with MS had to change at least 0.50 point on the CIQ, 1.5 points on the MSQOL physical and 2.5 points on the MSQOL mental to be judged as having clinically changed.

The impact of ergonomics intervention on trunk posture and cumulative compression load among carpet weavers.

BACKGROUND Work-related musculoskeletal disorders of back among weavers are prevalent. Epidemiological studies have shown an association between poor working postures and back disorders among carpet weavers. Therefore, the present study aimed to evaluate the impact of the traditional (A) and ergonomically designed (B) workstations on trunk posture and cumulative compression load in carpet weavers. METHODS In this study, subtasks were identified in terms of stressful postures and carpet weaving process. Postural data were collected during knotting and compacting subtasks using inclinometer during four hours for each workstation. Postural data, weight and height of the weavers were entered into the University of Michigan three-dimensional static biomechanical model for estimation of the compression load and cumulative load were estimated from the resultant load and exposure time. PARTICIPANTS Thirteen healthy carpet weavers (four males and nine females) participated in the study. RESULTS Median trunk flexion angle was reduced with workstation B during knotting subtask (18° versus 8.5°, p< 0.01 in males; 18.5° versus 7°, p< 0.001 in females). Average cumulative compression load was reduced with workstation B (22.17MN-s versus 16.68MN-s, p < 0.01 in males; 13.05 MN-s versus 10.14, p < 0.001 in females). CONCLUSIONS Using workstation B led to significant decrease in cumulative compressive loading during an entire shift (8 hours), which indicates reduced level of stress on the back. It is suggested to conduct biomechanical studies on the shoulder and wrist regions in carpet weavers in order to achieve further development and improvement in the ergonomically designed workstation.

The effects of a short-term memory task on postural control of stroke patients

Abstract Background: Many studies have been conducted on the changes in the balance capabilities of stroke patients. However, results regarding the effects of dual-task activities on postural control in these patients have been variable. Objective: To evaluate the effects of a short-term memory task on the sway characteristics of stroke patients. Method: Center of pressure (COP) fluctuations were measured in three levels of postural difficulty (rigid surface with closed and open eyes and foam surface with closed eyes), as well as two levels of cognitive difficulty (easy and difficult). COP parameters included mean velocity, standard deviation of velocity in both medial–lateral (M.L) and anterior–posterior (A.P) directions, total phase plane portrait, area. Nineteen stroke patients and 19 gender, age, height, and weight matching healthy volunteers participated in this study. Results: Our findings indicate that mean velocity (F = 14.21, P = 0.001), standard deviation of velocity in both M.L (F = 17.50, P = 0.000) and A.P (F = 11.03, P = 0.002) directions, total phase plane portrait (F = 44.12, P = 0.001), and area (F = 13.95, P = 0.01) of center of pressure of patients were statistically greater than normal subjects, while significant interaction of group × postural difficulty and postural × cognitive difficulty were observed for all parameters of postural sway. Conclusions: Different measures of postural sway showed complex response to postural and cognitive difficulties between stroke patients and normals. Cognitive error was not affected by the main effects of group and postural difficulty, while greatly increased at more difficult cognitive task (F = 75.73, P = 0.000).