Test-retest reliability and responsiveness of centre of pressure measurements in patients with hip osteoarthritis.

OBJECTIVE: The aim of this study was to determine a set of measures for the evaluation of balance in patients suffering from hip osteoarthritis (OA) that were both reliable and responsive to change. DESIGN: Three groups of subjects; Healthy, hip OA patients without surgery, and hip OA with surgery (pre and post-surgery) were included in this study. Subjects had to perform balance tests in two positions: standard and narrowed stance. CoP-based measures test-retest reliability was assessed in hip OA without surgery group, responsiveness were assessed between all groups and between pre and post-surgery. RESULTS: Intraclass Correlation Coefficient (ICC) values from hip OA without surgery ranged from -0.03 to 0.9 for only five parameters (CoP path length, SD velocity, mean velocity, and antero-posterior Root Mean Square (RMS(AP)) having values over 0.7. SD velocity and RMS(AP) showed significant differences between healthy and surgery group in standard stance whereas narrowed stance revealed most differences between all groups. RMS(AP) showed the best responsiveness (Standardized Response Mean ∼0.5) between pre vs post-surgery in both conditions. RMS(AP) was also capable of discriminating between hip OA with surgery vs without surgery groups with good sensitivity and specificity. CONCLUSIONS: Our results showed there to be reliability and responsiveness of five postural parameters in hip OA patients in two conditions of standing balance. More parameters were significantly different in narrowed stance whereas sensitivity was better in standard stance. SD velocity and RMS(AP) discriminate between degrees of OA severity and highlight potential balance deficits even after arthroplasty. Selected parameters during standing balance could be assessed to complete the set of quantitative measures to quantify hip OA patient deficiencies.

Sex differences in blood flow restricted isotonic knee extensions to fatigue.

AIM: It has been shown that females have greater muscular endurance than males and that this advantage is eliminated when blood flow is restricted. It is unknown if sex differences in dynamic endurance exist during low-load blood flow restricted (BFR) resistance exercise. The purpose of this study was to investigate sex differences in quadriceps femoris fatigability during isotonic knee extension exercise coupled with a blood flow restriction. METHODS: Ten males and ten females completed three sets of low-load isotonic knee extension exercises (20% of peak torque) to volitional failure under two conditions: blood flow restricted (BFR) and non-restricted free flow (FF). The number of repetitions, exercise volume, post-exercise strength loss and surface electromyography (EMG) were measured. RESULTS: Females performed more repetitions than males in the FF (252±37 vs. 112±17 repetitions; P<0.01) and BFR conditions (165±29 vs. 79±8 repetitions; P<0.01). Both sexes performed ~30% fewer repetitions during the BFR condition. MVC torque decreased approximately 37% following both conditions (P<0.01) and EMG activity increased (P<0.05) during the exercise bouts. CONCLUSION: Similar fatigue characteristics were evident in FF and BFR conditions for both sexes, and females demonstrated greater endurance, as determined by the number of repetitions completed, in both conditions. It may be beneficial to increase the relative exercise load for females in order to decrease the time under BFR.

Reproducibility, validity and responsiveness of the 200-metre fast walk test in patients undergoing cardiac rehabilitation.

OBJECTIVE: To investigate the reliability, validity and responsiveness of the 200-metre fast walk test in patients with coronary artery disease engaged in a cardiac rehabilitation programme. DESIGN: Descriptive study. SETTING: Tertiary care hospital. SUBJECTS: Thirty stable patients with coronary artery disease (51.9 ± 8.7 years), referred to the cardiac rehabilitation department after an acute coronary syndrome. INTERVENTION: Not applicable. MAIN MEASURES: Six-minute walk test distance, time to perform the 200-m fast walk test, peak power output of the graded maximal exercise test, before and after the programme; SF-36 quality of life questionnaire at baseline. Walk tests were performed twice at baseline to assess reliability. RESULTS: The 200-m fast walk test was highly reliable (ICC = 0.97). It was significantly correlated with the graded maximal exercise test peak power and the 6-minute walk test at baseline (r = -0.417; P < 0.05; and r = -0.566; P < 0.01, respectively) and after the training programme (r = -0.460, P < 0.05; and r = -0.926; P < 0.01, respectively). At baseline, there was a strong correlation between the 200-m fast walk test time and the physical component score of the SF-36 (r = -0.77; P < 0.01), but not between the 200-m fast walk test time and the SF-36 mental component score. Mean 200-m fast walk test time was significantly different between the patients performing ≤90 W (n = 11) or ≥100 W (n = 19) at the baseline graded maximal exercise test (121.7 ± 13.6 vs. 115.5 ± 10.1 seconds; P < 0.05). The responsiveness was strong with a standardized response mean at 1.11. CONCLUSION: The 200-m fast walk test is a reliable, valid and responsive high-intensity walk test in patients with coronary artery disease after an acute coronary syndrome. It can thus give additional information to that given by the 6-minute walk test and the graded maximal exercise test.

3 Different types of strength training in older women.

The objective of the present study was to evaluate and compare the neuromuscular, morphological and functional adaptations of older women subjected to 3 different types of strength training. 58, healthy women (67 ± 5 year) were randomized to experimental (EG, n=41) and control groups (CG, n=17) during the first 6 weeks when the EG group performed traditional resistance exercise for the lower extremity. Afterwards, EG was divided into three specific strength training groups; a traditional group (TG, n=14), a power group (PG, n=13) that performed the concentric phase of contraction at high speed and a rapid strength group (RG, n=14) that performed a lateral box jump exercise emphasizing the stretch-shortening-cycle (SSC). Subjects trained 2 days per week through the entire 12 weeks. Following 6 weeks of generalized strength training, significant improvements occurred in EG for knee extension one-repetition (1RM) maximum strength (+19%), knee extensor muscle thickness (MT, +15%), maximal muscle activation (+44% average) and onset latency ( -31% average) for vastus lateralis (VL), vastus medialis (VM) and rectus femoris (RF) compared to CG (p<0.05). Following 6 more weeks of specific strength training, the 1RM increased significantly and similarly between groups (average of +21%), as did muscle thickness of the VL (+25%), and activation of VL (+44%) and VM (+26%). The onset latency of RF (TG=285 ± 109 ms, PG=252 ± 76 ms, RG=203 ± 43 ms), reaction time (TG=366 ± 99 ms, PG=274 ± 76 ms, RG=201 ± 41 ms), 30-s chair stand (TG=18 ± 3, PG=18 ± 1, RG=21 ± 2) and counter movement jump (TG=8 ± 2 cm, PG=10 ± 3 cm, RG=13 ± 2 cm) was significantly improved only in RG (p<0.05). At the end of training, the rate of force development (RFD) over 150 ms (TG=2.3 ± 9.8 N·s(-1), PG=3.3 ± 3.2 N·s(-1), RG=3.8 ± 6.8 N·s(-1), CG=2.3 ± 7.0 N·s(-1)) was significantly greater in RG and PG than in TG and CG (p<0.05). In conclusion, rapid strength training is more effective for the development of rapid force production of muscle than other specific types of strength training and by consequence, better develops the functional capabilities of older women.

Influence of childhood maltreatment on prevalence, onset, and persistence of psychiatric comorbidities and suicide attempts in bipolar disorders.

BACKGROUND: Psychiatric comorbidities and suicide attempts are highly prevalent in Bipolar Disorders (BD). We examined the associations between childhood maltreatment, psychiatric comorbidities, and suicide attempts, in terms of lifetime prevalence, sequence of onset, and current symptoms. METHODS: We assessed 3,047 individuals with BD for suicide attempts, anxiety disorders, substance use disorders, and eating disorders. Participants completed a self-report for the assessment of childhood maltreatment. Associations between childhood maltreatment and characteristics of comorbidities (lifetime prevalence, current symptoms, and age at onset) were examined using logistic regressions and network analyses. RESULTS: Psychiatric comorbidities were frequent with a mean number per individual of 1.23 (SD = 1.4). Most comorbidities occurred prior to the onset of BD. Participants who reported higher levels of childhood maltreatment had more frequent and multiple comorbidities, which were also more currently active at inclusion. Childhood maltreatment did not decrease the age of onset of comorbidities, but was associated with a faster accumulation of comorbidities prior to the onset of BD. Logistic regression and network analyses showed that emotional abuse and sexual abuse might play a prominent role in the lifetime prevalence of psychiatric comorbidities and suicide attempts. CONCLUSIONS: Childhood maltreatment was associated with suicide attempts, and with frequent, multiple, and persistent psychiatric comorbidities that accumulated more rapidly prior to the onset of BD. Hence, childhood maltreatment should be systematically assessed in individuals with BD, in particular when the course of the disorder is characterized by a high comorbid profile or by a high suicidality.

Test-retest reliability of 3D kinematic gait variables in hip osteoarthritis patients.

OBJECTIVES: (1) to investigate the test-retest reliability of 3D gait analysis (3DGA) in hip Osteoarthritis (OA) patients; (2) to find the minimum number of gait trials needed to overcome intrinsic variability; (3) to check the accuracy of angles measured by the 3D system. DESIGN: 23 Patients suffering from hip OA with no other major disease were recruited. We evaluated the reliability of spatio-temporal variables and body angles (lower-limb joints, trunk and pelvis angles) during two sessions of 3DGA using intra-class correlation coefficients (ICC). The minimum number of trials needed to overcome intrinsic variability was evaluated using an exponential fit model and the Bland and Altman coefficient of repeatability (CoR). The accuracy of measurement was evaluated using a manual goniometer and the recording of 18 different angles. RESULTS: Spatio-temporal variables and most of the kinematic joint and trunk angles calculated demonstrated good to excellent reliability (ICC from 0.77 to 0.97). This was not the case for pelvic angles. The fitting model combined with the CoR showed that 5-10 trials are sufficient to obtain good reliability [ICC>0.7; CoR<2 standard deviation (SD)] for most of the spatio-temporal variables. All body angles showed good reliability (ICC>0.7) and low CoR (<2 SD) after five trials except for the pelvic angles. The reliability of marker positioning was found to be good (ICC>0.7) to excellent (ICC>0.9). Differences between angles measured using 3DGA and angles measured with a manual goniometer were found to be less than one percent. CONCLUSION: The present study shows that most of variables obtained using 3DGA in hip OA patients are reliable. Moreover, for most variables, 5-10 trials are needed to obtain good reliability and to overcome intrinsic variability, rather than 30 or more, thus improving the feasibility of measurement.

Hypersensitivity reactions to blood components: document issued by the allergy committee of the French medicines and healthcare products regulatory agency.

These guidelines represent a consensus among experts on hypersensitivity reactions occurring after transfusion of blood components. They cover recognition, investigation, treatment, and prevention of such reactions. Implemented in France under the auspices of the French Medicines and Healthcare Products Regulatory Agency (AFSSAPS) and based on current knowledge, research, and experience, they aim to provide effective and easily teachable means of further improving the quality of hemovigilance databases, promote interest in this field, and help identify possible mechanisms and at-risk patient groups.

Usefulness of the 6-minute walk test and the 200-metre fast walk test to individualize high intensity interval and continuous exercise training in coronary artery disease patients after acute coronary syndrome: a pilot controlled clinical study.

OBJECTIVE: To study the effects of three individualized exercise training prescriptions using either a percentage of maximal heart rate (HR), maximal 6-minute walk test (6MWT) HR, or maximal 200-metre fast walk test (200-mFWT) HR, on walking performance and exercise capacity in coronary artery disease (CAD) patients. DESIGN: Controlled clinical study. PARTICIPANTS: Twenty-seven outpatients enrolled in a rehabilitation programme after an acute coronary syndrome. SETTING: Cardiac rehabilitation unit. INTERVENTIONS: Three groups: (A): moderate intensity continuous exercise (MICE) at 70% of the maximal HR of the graded maximal exercise test (n = 10); (B): MICE at the maximal 6MWT HR (n = 8); (C): high intensity interval training (HIIT) based on the 6MWT and the 200-mFWT maximal HR (n = 9). Group B and C performed walk tests every 2 weeks, to readjust training HR (THR) if needed. MEASURES: 6MWT and 200-mFWT performances, peak VO(2) and peak power (Pmax). RESULTS: 6MWT and 200-mFWT performances improved significantly and similarly in all groups (P < 0.05). Peak VO(2) improved significantly in all groups (P < 0.05), this improvement being higher in group C (HIIT) versus A (P < 0.05). Group B was closer to the recommended THR during exercise sessions compared to group A. CONCLUSION: This pilot study showed that using the 6MWT and 200-mFWT HR to individualize MICE or HIIT prescription is feasible in CAD patients, and could lead them closer to THR objective, to similar improvements in walking performance, and greater peak VO(2) increase for HIIT. Future randomised studies should investigate long-term effects of programmes prescribed from walk tests HR, especially for HIIT modality.

The Frail'BESTest: an adaptation of the "balance evaluation system test" for frail older adults; Concurrent validity, responsiveness, validity for fall prediction and detection of slower walkers.

BACKGROUND: The Frail'BESTest was developed in order to include frail older adults when they are using the BESTest. Recently, psychometrics properties (internal coherence, systems usefulness, complementarity and inter-rater reliability) of the Frail'BESTest were tested. To complete these analyses, this study will aim the assessment of its concurrent validity, responsiveness, predictive validity on falls occurrence, and slower walkers detection. METHODS: The correlation between the Frail'BESTest and the Gait Speed Test permitted to assess concurrent validity. The variation between the initial test score and the score obtained after the completion of a rehabilitation program was used to evaluate responsiveness with MANOVA analysis and standard response mean (SRM) calculation. Predictive validity was assessed with receiver-operating characteristic curves and area under the curve (AUC) analysis regarding falls occurrence. Slower walkers detection thresholds were computed by receiver-operating characteristic curves for the Frail'BESTest and the Tinetti test. RESULTS: The concurrent validity of the test was good (r = 0.74; p < 0.001). The Standard Error of measurement was at 2.81 points and the Minimal Detectable Change at 7.79 points for the total score of the Frail'BESTest. The SRM was at 0.41 for the Tinetti test and 0.56 for the Frail'BESTest. The AUC, computed according to fall occurrence, was at 0.71 for the Gait Speed test, 0.673 for the Tinetti test and 0.693 for the Frail'BESTest. Both the Tinetti (AUC = 0.87) and the Frail'BESTest (AUC = 0.88) were found suitable for tracking slower walkers. CONCLUSION: Concurrent validity and responsiveness of the Frail'BESTest were good. As for the Tinetti and the Frail'BESTest, they were unable to predict efficiently falls occurrence in the tested sample. The Frail'BESTest seems enough sensitive to spot the slower walkers efficiently, using a 15/20 threshold method. The Frail'BESTest was found to be a valid and responsive clinical test, therefore it can be recommended as an outcome measure in clinical practice.

Network of co-expressed circadian genes, childhood maltreatment and sleep quality in bipolar disorders.

Bipolar disorder (BD) is a chronic and burdensome psychiatric disease, characterized by variations in mood and energy. The literature has consistently demonstrated an association between BD and childhood maltreatment (CM), and genetic variants of circadian genes have been associated with an increased vulnerability to develop BD. In this context, environmental factors such as CM may also contribute to the susceptibility to BD through alterations in the functioning of the biological clock linked to modifications of expression of circadian genes. In this study, we explored the associations between childhood maltreatment, sleep quality, and the level of expression of a comprehensive set of circadian genes in lymphoblastoid cell lines from patients with BD. The sample consisted of 52 Caucasian euthymic patients with a diagnosis of BD type 1 or type 2. The exposure to CM was assessed with the Childhood Trauma Questionnaire (CTQ), and the sleep quality was assessed using the Pittsburgh Sleep Quality Index. We measured the expression of 18 circadian genes using quantitative RT-PCR: ARNTL2, BHLHE40, BHLHE41, CLOCK, CRY1, CRY2, CSNK1D, CSNK1E, DBP, GSK3B, NPAS2, NR1D1, PER1, PER2, PER3, PPARGC1A, RORA, and RORB. Gene expression networks were analyzed with the disjoint graphs method. Compared to the other investigated transcripts, PPARGC1A was the only one whose expression level was differentially affected in patients who have experienced CM and, more specifically, physical abuse. We observed no significant effects of the other CTQ subscores (emotional and sexual abuses, physical and emotional neglects), nor of the sleep quality on the network of circadian genes expression. Although requiring replication in larger cohorts, the result obtained here is consistent with the hypothesis of an influence of CM exposure on circadian systems and highlights the importance of PPARGC1A in these processes.

Cross-cultural adaptation and validation of the French version of the Rheumatoid and Arthritis Outcome Score (RAOS).

OBJECTIVES: The Rheumatoid and Arthritis Outcome Score (RAOS) was recently developed to evaluate functional disability and quality of life in rheumatoid arthritis (RA) patients suffering from lower limb symptoms. The aims of this study were to cross-culturally adapt the RAOS into French and to assess its psychometric properties, in particular, responsiveness following intra-articular therapy. METHODS: The French RAOS was developed according to cross-cultural guidelines and was then evaluated in symptomatic RA patients with lower limb joint involvement. The psychometric properties assessed were - feasibility: percentage of missing data and floor and ceiling effects; reliability: intra-class correlation coefficients (ICC, and Bland and Altman representation; internal consistency: Cronbach's alpha; construct validity by correlation with the SF-36 and HAQ (Spearman's rank test); responsiveness to intra-articular corticosteroid injection (hip, knee, hindfoot) using standardised response mean (SRM) and effect size. RESULTS: Sixty patients were included (mean age 50.1±10.5 years). Neither floor nor ceiling effects were observed. Reliability was good with ICC for different RAOS subscales ranging from 0.76 to 0.91. Results for internal consistency (Cronbach's alpha ranging from 0.73 to 0.91) and construct validity were good. The responsiveness was moderate to large with SRMs ranging from 0.75 to 0.87 and effect sizes from 0.77 to 1.75 at two weeks following intra-articular corticosteroid injection. CONCLUSIONS: The French version of the RAOS demonstrated good psychometric properties to capture functional disability and quality of life in RA. Moreover, the results suggest that the RAOS could be used as an outcome in trials evaluating single joint intra-articular injections.

Does eccentric endurance training improve walking capacity in patients with coronary artery disease? A randomized controlled pilot study.

OBJECTIVE: To examine the effect of eccentric endurance training on exercise capacities in patients with coronary artery disease. DESIGN: Randomized parallel group controlled study. SETTING: Cardiac rehabilitation unit, Dijon University Hospital. PARTICIPANTS: Fourteen patients with stable coronary artery disease after percutaneous coronary intervention. INTERVENTION: Patients followed 15 sessions of training (1 session per day, 3 days a week), either in the concentric group, following a standard programme, or in the eccentric group, performing eccentric resistance exercises using both lower limbs on a specifically designed ergometer. MAIN OUTCOMES MEASURED: Symptom-limited Vo2, peak workload, isometric strength of leg extensor and ankle plantar flexors, distance covered during the 6-minute walk test and time to perform the 200-m fast walk test in both groups, before and after the training period. RESULTS: Patients did not report any adverse effects and were highly compliant. All measured parameters improved in eccentric and concentric group, except for 200-m fast walk test: symptom-limited Vo2 (+14.2% versus +4.6%), peak workload (+30.8% versus +19.3%), 6-minute walk test distance walked (+12.6% versus +10.1%) and leg extensor strength (+7% versus +13%) improved to a similar degree in both groups (P < 0.01); ankle plantar flexor strength improved in both groups with a significantly greater increase in the eccentric group (+17% versus +7%, P < 0.05). CONCLUSION: Patients with stable coronary artery disease can safely engage in eccentric endurance training, which appears to be as efficient as usual concentric training, with reduced oxygen consumption.

The Frail'BESTest. An Adaptation of the "Balance Evaluation System Test" for Frail Older Adults. Description, Internal Consistency and Inter-Rater Reliability.

INTRODUCTION: The Balance Evaluation System Test (BESTest) and the Mini-BESTest were developed to assess the complementary systems that contribute to balance function. These tests include functional tasks involving several high-level exercises to assess the balance function, which may be even more difficult in case of frailty. The Frail'BESTest has been developed to make it possible to include frail older adults in systemic assessment. In this first paper, the objective is to present the Frail'BESTest and to describe the usefulness and complementarity of each system and to test the inter-rater reliability of the score measurements in two health centers. METHODS: In the first center, 192 frail and non-frail older patients were enrolled to test I) the contribution of each system, II) internal consistency, and III) the threshold and ceiling effects. The scores of 32 patients from center 1 and 32 patients recruited in another center (center 2) were used to measure the inter-rater reliability of the measurements by means of Kendall's tau coefficients. RESULTS: The internal consistency was moderate to good for five systems and limited for "biomechanical constraints". The distribution of the Frail'BESTest was more centered than that of the Tinetti and Mini-Motor tests. The Kendall's tau showed strong concordance in center 1 for all systems and only for 4 on 6 systems in center 2. DISCUSSION: Completing a systemic evaluation, the therapist may prioritize the patient's needs identifying the most challenging systems. This paper presents the Frail'BESTest and confirms the psychometric properties at a first step level.

Childhood maltreatment and HPA axis gene expression in bipolar disorders: A gene network analysis.

INTRODUCTION: Bipolar disorder (BD) is highly associated with childhood maltreatment (CM), the exposure to such early adversity being suggested to disrupt the expression of several biological pathways. This study aims at exploring associations between the mRNA levels of 9 HPA axis genes in lymphoblastoid cell lines from patients with BD according to their self-reported exposure to CM. METHODS: The sample consisted of 33 Caucasian patients with a diagnosis of BD type 1, assessed for the exposure to CM with the Childhood Trauma Questionnaire (CTQ). Quantitative RT-PCR was performed on 9 transcripts of the HPA axis genes: DGKH, FKBP5, NR3C1, SGK1, SGK2, SGK3, SKA2, STAT5A and UCN. RT-qPCR data were analyzed using the method of disjoint gene networks with SARP.compo package for R. RESULTS: We found no associations between CTQ total score and the amount of HPA axis transcripts neither in univariate analyses, nor with network analyses. Emotional abuse (EA) was associated with a significant decreased expression of two transcripts, DGKH (p = 0.009) and NR3C1 (p = 0.04). This was confirmed by the disjoint network analysis, which showed that NR3C1 and DGKH were expressed differently from the rest of the HPA axis network in presence of emotional abuse. DISCUSSION: This study described the expression levels of a comprehensive set of HPA axis genes according to childhood maltreatment in a sample of patients with BD type 1 and suggested that emotional abuse decreased the expression of NR3C1 and DGKH. Our results require further replication in independent larger samples.

[Immediate allergy to iodinated contrast agents and prevention of reactions]. / Allergie immédiate aux produits de contraste iodés et prévention des réactions.

The incidence and morbimortality of immediate hypersensitivity reactions following iodinated contrast media (ICM) injection remain unknown. The diagnosis of an immediate hypersensitivity reaction relies on a triad associating the precise description of the initial clinical manifestations and their delay of onset, the results of the biological assessment performed after the reaction including histamine and tryptase serum level measurements, and the results of skin testing with the culprit agent. Analysis of these data allows identification of the pathophysiologic mechanism of the reaction and the allergen involved in case of allergic hypersensitivity. Skin tests should be performed according to strict criteria. Cross-reactivity with ICM has to be investigated in order to propose a nonreactive ICM for future procedures. Allergic hypersensitivity to a given ICM imposes its definitive avoidance but not the avoidance of all iodinated drugs. The allergenic sequence has not yet been identified but is not the iodine atom itself. Asthma and treatment with beta-blockers are not risk factors of immediate allergic reactions to ICM per se, but may increase their severity. The various published protocols of premedication do not prevent the occurrence of an allergic/anaphylactic reaction to an ICM. The avoidance of the culprit ICM is the only way to prevent further reactions.

Barriers to physical activity in coronary artery disease patients: Development and validation of a new scale.

OBJECTIVE: To develop and validate a self-report questionnaire to measure barriers to regular physical activity (PA) in patients with stable coronary artery disease (CAD). METHODS: Phase 1: 17 patients completed a semi-structured interview. After grouping and reformulating the reported barriers, their pertinence was reevaluated by the patients. Then, a decision algorithm was used to select items. A principal component analysis was performed to determine content validity. Phase 2: 49 patients completed the questionnaire resulting from phase 1 twice, 7 days apart, and questionnaires to evaluate depression, anxiety, and the level of physical activity. Construct validity was evaluated by analysis of Spearman's correlation coefficient between the total score for the questionnaire and a convergent dimension (anxiety), as well as a divergent dimension (Dijon physical activity score). Internal consistency was evaluated by Cronbach's alpha coefficient. Test-retest reliability was evaluated by the intraclass coefficient (ICC). RESULTS: Eleven items were selected after phase 1. The questionnaire presented good face validity and the content validity seemed satisfactory after analysis of the literature by the experts. Construct validity was moderate. Internal consistency was very good (Cronbach's α>0.81). Reproducibility was excellent with an ICC at 0.95. Feasibility was good with less than 3minutes to complete the questionnaire. CONCLUSION: This questionnaire presents good psychometric properties. A further prospective study should evaluate sensitivity to change and help determine a threshold value indicating the need for a specific behavioral strategy to alleviate barriers to physical activity in these patients.

Density-controlled quantum Hall ferromagnetic transition in a two-dimensional hole system.

Quantum Hall ferromagnetic transitions are typically achieved by increasing the Zeeman energy through in-situ sample rotation, while transitions in systems with pseudo-spin indices can be induced by gate control. We report here a gate-controlled quantum Hall ferromagnetic transition between two real spin states in a conventional two-dimensional system without any in-plane magnetic field. We show that the ratio of the Zeeman splitting to the cyclotron gap in a Ge two-dimensional hole system increases with decreasing density owing to inter-carrier interactions. Below a critical density of ~2.4 × 1010 cm-2, this ratio grows greater than 1, resulting in a ferromagnetic ground state at filling factor ν = 2. At the critical density, a resistance peak due to the formation of microscopic domains of opposite spin orientations is observed. Such gate-controlled spin-polarizations in the quantum Hall regime opens the door to realizing Majorana modes using two-dimensional systems in conventional, low-spin-orbit-coupling semiconductors.

[High cord blood TSH in Morocco: iatrogenic hypothyroidism?]. / TSH au cordon élevées au Maroc: hypothyroïdie iatrogène?

A short prospective study was conducted to assess thyroid status in healthy full term newborns (n=90) of a large maternity of Marrakech (Morocco), as part of the validation of a national salt iodisation program. High TSH (>5mU/l) was detected in 89% of infants tested; urinary iodine excretion was measured in 35 of the mothers, and was found to be normal (100-200microg/l) or high (>200microg/l)(n=27) in all of them. Milk iodine concentration was measured in 315 lactating women from the same area. Low values (<41microg/l) were found in 60% of them. The common use of iodinated disinfectants during delivery could be responsible for the high urine iodine values of mothers; however iodine deficiency seems to remain a widespread problem in this population and justifies a large scale survey of iodine status.

The involvement of ankle muscles in maintaining balance in the upright posture is higher in elderly fallers.

The purpose of this study was to determine whether the mechanical contribution of ankle muscles in the upright stance differed among young adults (YA) (n=10, age: ~24.3), elderly non-fallers (ENF) (n=12, age: ~77.3) and elderly fallers (EF) (n=20, age: ~80.7). Torque and electromyographic (EMG) activity were recorded on the triceps surae and tibialis anterior during maximum and submaximum contractions in the seated position. EMG activity was also recorded in subjects standing still. Plantar flexor (PF) and dorsal flexor (DF) torques generated in the upright posture were estimated from the torque-EMG relationship obtained during submaximum contractions in the seated position. Center of pressure (CoP) displacement was measured to quantify postural stability. Results showed that, in upright standing, EF generated greater ankle muscle relative torque (i.e. PF+DF torque in the upright stance/PF+DF during maximum isometric torque) than non-fallers (i.e. ENF, YA). The greater involvement of ankle muscles in EF was associated with higher CoP displacement. PF+DF torque in the upright stance was no different among the groups, but PF+DF torque during maximum effort was impaired in older groups compared with YA and was lower in EF than ENF. These results suggest that the postural stability impairment observed with aging is highly related to ankle muscle weakness.