Factors influencing the use of an artificial intelligence-based app (selfBACK) for tailored self-management support among adults with neck and/or low back pain.

PURPOSE: Tailored self-management support is recommended as first-line treatment for neck and low back pain, for which mHealth applications could be promising. However, there is limited knowledge about factors influencing the engagement with such apps. The aim of this study was to assess barriers and facilitators for engaging with a self-management mHealth app among adults suffering from neck and/or low back pain. MATERIALS AND METHODS: We carried out a qualitative descriptive study among adults with neck and/or low back pain. The artificial intelligence-based selfBACK app supports tailored self-management of neck and low back pain and was used for 6 weeks. After these 6 weeks, participants were interviewed by phone. RESULTS: Thirty-two adults (17 males) with neck and/or low back pain participated (mean age = 54.9 (SD = 15.8)). Our results show that the mode of delivery and the novelty of the selfBACK app were perceived most often as a barrier to use the app. The action plans of the app and health-related factors were perceived most often as facilitating factors. CONCLUSIONS: This study provides insight into possible strategies to improve an mHealth service. Furthermore, it shows that adults with neck and/or low back pain are willing and ready to receive blended treatment.

Adults with neck and/or low back pain are willing to receive blended care (combination of face-to-face contact with healthcare professional and use of eHealth service)When implementing eHealth services in rehabilitation treatment of adults with neck and/or low back pain, rehabilitation professionals need to choose an eHealth service which includes individual action plans, evidence-based content with health benefits, goal setting and rewards and incentives.When implementing eHealth services in rehabilitation treatment of adults with neck and/or low back pain, rehabilitation professionals need to choose an eHealth service which can be used on someone's own smartphone.When implementing eHealth services in rehabilitation treatment of adults with neck and/or low back pain, rehabilitation professionals need to educate their patients about the importance and possible long-term benefits of self-managing their pain.

Chronic fatigue syndrome: Abnormally fast muscle fiber conduction in the membranes of motor units at low static force load.

OBJECTIVE: Chronic fatigue syndrome (CFS) and fibromyalgia (FM) are disorders of unknown etiology and unclear pathophysiology, with overlapping symptoms of - especially muscular -fatigue and pain. Studies have shown increased muscle fiber conduction velocity (CV) in the non-painful muscles of FM patients. We investigated whether CFS patients also show CV abnormalities. METHODS: Females with CFS (n = 25), with FM (n = 22), and healthy controls (n = 21) underwent surface electromyography of the biceps brachii, loaded up to 20% of maximum strength, during short static contractions. The mean CV and motor unit potential (MUP) velocities with their statistical distribution were measured. RESULTS: The CV changes with force differed between CFS-group and both FM-group and controls (P = 0.01). The CV of the CFS-group increased excessively with force (P < 0.001), whereas that of the controls increased only slightly and non-significantly, and that of the FM-group did not increase at all. In the CFS-group, the number of MUPs conveying very high conduction velocities increased abundantly with force and the MUPs narrowed. CONCLUSION: Our results suggest disturbed muscle membrane function in CFS patients, in their motor units involved in low force generation. Central neural deregulation may contribute to this disturbance. SIGNIFICANCE: These findings help to detangle the underlying mechanisms of CFS.

WEARCON: wearable home monitoring in children with asthma reveals a strong association with hospital based assessment of asthma control.

BACKGROUND: Asthma is one of the most common chronic diseases in childhood. Regular follow-up of physiological parameters in the home setting, in relation to asthma symptoms, can provide complementary quantitative insights into the dynamics of the asthma status. Despite considerable interest in asthma home-monitoring in children, there is a paucity of scientific evidence, especially on multi-parameter monitoring approaches. Therefore, the aim of this study is to investigate whether asthma control can be accurately assessed in the home situation by combining parameters from respiratory physiology sensors. METHODS: Sixty asthmatic and thirty non-asthmatic children were enrolled in the observational WEARCON-study. Asthma control was assessed according to GINA guidelines by the paediatrician. All children were also evaluated during a 2-week home-monitoring period with wearable devices; a physical activity tracker, a handheld spirometer, smart inhalers, and an ambulatory electrocardiography device to monitor heart and respiratory rate. Multiple logistic regression analysis was used to determine which diagnostic measures were associated with asthma control. RESULTS: 24 of the 27 uncontrolled asthmatic children and 29 of the 32 controlled asthmatic children could be accurately identified with this model. The final model showed that a larger variation in pre-exercise lung function (OR = 1.34 95%-CI 1.07-1.68), an earlier wake-up-time (OR = 1.05 95%-CI 1.01-1.10), more reliever use (OR = 1.11 95%-CI 1.03-1.19) and a longer respiratory rate recovery time (OR = 1.12 95%-CI 1.05-1.20) were significant contributors to the probability of having uncontrolled asthma. CONCLUSIONS: Home-monitoring of physiological parameters correlates with paediatrician assessed asthma control. The constructed multivariate model identifies 88.9% of all uncontrolled asthmatic children, indicating a high potential for monitoring of asthma control. This may allow healthcare professionals to assess asthma control at home. TRIAL REGISTRATION: Netherlands Trail Register, NL6087 . Registered 14 February 2017.

Does exercise-induced bronchoconstriction affect physical activity patterns in asthmatic children?

Exercise-induced bronchoconstriction (EIB) is a sign of uncontrolled childhood asthma and classically occurs after exercise. Recent research shows that EIB frequently starts during exercise, called breakthrough-EIB (BT-EIB). It is unknown whether this more severe type of EIB forces children to adapt their physical activity (PA) pattern in daily life. Therefore, this pilot study aims to investigate daily life PA (amount, intensity, duration, and distribution) in children with BT-EIB, 'classic' EIB, and without EIB. A Fitbit Zip activity tracker was used for one week to objectively measure daily life PA at one-minute intervals. Thirty asthmatic children participated. Children with BT-EIB were less physically active compared to children without EIB (respectively 7994 and 11,444 steps/day, p = .02). Children with BT-EIB showed less moderate-to-vigorous PA compared to the children without (respectively 117 and 170 minutes/day, p = .02). Children with EIB (both BT and classic) had significant shorter bouts of activity and a less stretched distribution of bout lengths compared to the non-EIB group (all p < .05). These results emphasize a marked association between EIB severity and PA patterns in daily life, stressing the need for a thorough clinical evaluation of exercise-induced symptoms in childhood asthma.

Ambulant monitoring and web-accessible home-based exercise program during outpatient follow-up for resected lung cancer survivors: actual use and feasibility in clinical practice.

PURPOSE: The aim of this study is to evaluate the feasibility of a telehealthcare application for operable lung cancer (OLC) patients, consisting of ambulant symptom and physical activity monitoring (S&PAM) and a web-accessible home-based exercise program (WEP), and identify possible barriers for successful adoption and implementation. METHODS: A two-stage mixed methods design was used, in which 22 OLC patients and their treating healthcare professionals (HCPs) participated from pre-surgery to three (stage 1; n = 10) or six (stage 2; n = 12) months post-surgery. Actual use and acceptability (usability, usefulness, and satisfaction) were evaluated. RESULTS: Seventeen OLC patients (age (SD): 59 (8) years; 8 female) actively used the modules. S&PAM use varied from 1 to 11 monitoring days prior to outpatient consultations. Patients used WEP most frequently during the first 5 weeks, with an average of four logins a week. Fifty-eight percent used WEP beyond 7 weeks. No adverse situations occurred, and patients felt confident using the applications. Perceived added value included active lifestyle promotion, decreased anxiety, and accessibility to specialized HCPs. Physiotherapists used WEP as intended. Contrarily, physicians scarcely used information from S&PAM. To promote future adoption, strategies should focus on high-level patient tailoring of the technology, and formalization of including the applications in the clinical workflow. CONCLUSIONS: Ambulant monitoring and web-accessible home exercise is clinically feasible for OLC patients. However, low level of adoption by referring physicians may hamper successful implementation. IMPLICATIONS FOR CANCER SURVIVORS: Patients perceived both ambulant monitoring and web-accessible exercise as an added value to regular care and feasible to use in the period before and after lung resection.

Usability in telemedicine systems-A literature survey.

INTRODUCTION: The rapid development of sensors and communication technologies enable the growth of new innovative services in healthcare, such as Telemedicine. An essential ingredient in the development of a telemedicine system and its final acceptance by end users are usability studies. The principles of usability engineering, evaluations and telemedicine are well established, and it may contribute to the adoption and eventually deployment of such systems and services. An in-depth usability analysis, including performance and attitude measures, requires knowledge about available usability techniques, and is depending on the amount of resources. Therefore it is worth investigating how usability methods are applied in developing telemedicine systems. Our hypothesis is: with increasing research and development of telemedicine systems, we expect that various usability methods are more equally employed for different end-user groups and applications. METHOD: A literature survey was conducted to find telemedicine systems that have been evaluated for usability or ease of use. The elements of the PICO framework were used as a basis for the selection criteria in the literature search. The search was not limited by year. Two independent reviewers screened all search results first by title, and then by abstract for inclusion. Articles were included up to May 2015. RESULTS: In total, 127 publications were included in this survey. The number of publications on telemedicine systems significantly increased after 2008. Older adults and end-users with cardiovascular conditions were among largest target end-user groups. Remote monitoring systems were found the most, in 90 publications. Questionnaires are the most common means for evaluating telemedicine systems, and were found in 88 publications. Questionnaires are used frequently in studies focusing on cardiovascular diseases, Parkinson's disease and older adult conditions. Interviews are found the most in publications related to stroke. In total 71% of the publications were trial-orientated and the remaining process orientated. An increase in telemedicine research, development and applications is found worldwide, with the majority of publications conducted in America. DISCUSSION AND CONCLUSION: Monitoring patients in their homes can lead to better healthcare at lower costs which implies an increased demand of new healthcare strategies like telemedicine. We expected that with the increase in telemedicine research and development, a greater range of usability methods would also be employed in the included publications. This is not the case. Researchers employed questionnaires as a preferred usability method for each type of telemedicine system and most end-users. However, in process-orientated studies a greater range of usability evaluations were applied, with fewer differences found in the amount of publications for each evaluation method. Questionnaires enable researchers to evaluate a system quickly on end users, as it requires less expertise on the evaluation method compared to the other methods. They are easily distributed and are customizable. The use of questionnaires is therefore an evaluation method of choice for a variety of telemedicine systems and end-users.

Relationship between patterns of daily physical activity and fatigue in cancer survivors.

PURPOSE: This study investigated: (1) physical activity behaviour of cancer survivors throughout the day, (2) the relationship between objective and subjective measures of physical activity, and (3) the relationship between daily physical activity and fatigue. METHOD: Physical activity was measured objectively using 3D-accelerometry (expressed in counts per minute (cpm)), and subjectively using a Visual Analogue Scale (VAS; 0-10) implemented on a smartphone in 18 cancer survivors (6 male; age 55.7 ± 10.2 yrs; free from cancer, last treatment ≥three months previously), and matched controls. Fatigue was scored thrice daily on a smartphone (0-10 VAS). RESULTS: Mean daily physical activity of cancer survivors did not deviate from controls (1108 ± 287 cpm versus 1223 ± 371 cpm, p = .305). However, in cancer survivors physical activity significantly decreased from morning to evening (p < .01) and increased levels of fatigue throughout the day were reported (p < .01). Furthermore, a positive correlation was found between levels of fatigue and the magnitude of the decline in physical activity from afternoon to evening (p < .05). Objective and subjective measured physical activity showed low correlations. CONCLUSIONS: This study demonstrated imbalanced activity patterns in cancer survivors. Also, the more a survivor felt fatigued, the greater the decline in activity behaviour throughout the day. The low correlation between objective and subjective physical activity suggests low awareness in cancer survivors about their daily physical activity performed. Ambulatory monitoring provides new insights in both patterns of physical activity and fatigue, which might be a valuable tool to provide activity management more efficiently during treatment of fatigue.

Kinematic coupling relationships exist between non-adjacent segments of the foot and ankle of healthy subjects.

Pathologies of foot and ankle structures affect the kinematics at the site of the impaired structure but also influence kinematics elsewhere in the foot and ankle. An understanding of kinematic coupling relationships in the foot could provide insight into mechanisms that explain differences in foot and ankle kinematics between healthy and pathological subjects. The aim of this study was to explore foot and ankle kinematic coupling relationships between adjacent and non-adjacent segments of healthy subjects and evaluate individual variability of and effect of walking speed on these relationships. Gait of 14 subjects was recorded at comfortable and two slower walking speeds to assess individual foot kinematics during stance phase. A qualitative evaluation of the coupling relationships was made using angle-angle plots to determine their consistency, i.e. changes in movement direction of each segment occurred at the same time and the plot returned along the same line after the turning point. The Pearson correlation coefficient of determination (R(2)) was used to provide a quantitative evaluation of coupling. Individual variability was assessed with the coefficient of variation (CV). The Friedman-test was used to test the effect of walking speed. Consistent coupling relationships were observed between hindfoot in/eversion and hallux plantar/dorsiflexion (R(2) 0.7, CV 0.2), between hindfoot in/eversion and forefoot ab/adduction (R(2) 0.5, CV 0.3) and between leg rotation and midfoot collapse/elevation (R(2) 0.5, CV 0.4). Less or non-consistent coupling relationships were observed between the other studied segments. Walking speed significantly influenced coupling relationships between hindfoot and midfoot.

Intention detection of gait initiation using EMG and kinematic data.

Gait initiation in transfemoral amputees (TFA) is different from non-amputees. This is mainly caused by the lack of stability and push-off from the prosthetic leg. Adding control and artificial push-off to the prosthesis may therefore be beneficial to TFA. In this study the feasibility of real-time intention detection of gait initiation was determined by mimicking the TFA situation in non-amputees. EMG and inertial sensor data was measured in 10 non-amputees. Only data available in TFA was used to determine if gait initiation can be predicted in time to control a transfemoral prosthesis to generate push-off and stability. Toe-off and heel-strike of the leading limb are important parameters to be detected, to control a prosthesis and to time push-off. The results show that toe-off and heel-strike of the leading limb can be detected using EMG and kinematic data in non-amputees 130-260 ms in advance. This leaves enough time to control a prosthesis. Based on these results we hypothesize that similar results can be found in TFA, allowing for adequate control of a prosthesis during gait initiation.

Foot and ankle kinematics in rheumatoid arthritis: influence of foot and ankle joint and leg tendon pathologies.

OBJECTIVE: From early onset of the disease, patients with rheumatoid arthritis (RA) experience walking impairments. Pathologic effects of RA on foot and ankle structures have been studied clinically, but little is known as to how they relate to kinematic changes during gait. The aim of this study was to explore the relationship between clinically observed pathologies of foot and ankle joints and leg tendons and the corresponding gait kinematics. METHODS: The gait of 25 subjects with varying stages of RA was recorded and foot and ankle kinematics were assessed. Magnetic resonance imaging was performed for each subject: first metatarsophalangeal (MTP) joint, midfoot, and hindfoot synovitis, erosion scores, and leg tendon involvement were determined. The joint alignment and motion score represented daily clinical assessment. The 95% confidence intervals of the Spearman's correlation coefficient tests were used to explore the relationships between the clinical and kinematic parameters. RESULTS: Maximum first MTP joint dorsiflexion at preswing was related to reduced first MTP joint passive motion, first MTP joint synovitis and erosion, midfoot synovitis and erosion, and hindfoot erosion. Midfoot pronation range of motion during single stance was related to subtalar alignment and Achilles tendon involvement. Hindfoot eversion range of motion during single stance was related to subtalar alignment and peroneus longus tendon involvement. Involvement of the tibialis posterior tendon could not be identified as an independent factor influencing foot or ankle kinematics. CONCLUSION: Our findings suggest moderate to strong relationships between foot and ankle gait kinematics and structural pathologies.

The relationship between objectively and subjectively measured activity levels in people with chronic low back pain.

OBJECTIVE: To compare self-report measures of daily activities with objective activity data to determine whether patients with chronic lower back pain report their activity levels as accurately as controls do. DESIGN: A cross-sectional study was performed in patients and controls. SETTING: The study was carried out in the daily environment of the subjects. SUBJECTS: Thirty-two chronic lower back pain patients with symptoms more than three months and 20 healthy controls from the Netherlands, aged 18-65 years. MAIN MEASURES: A tri-axial accelerometer was worn for five weekdays and the Baecke Physical Activity Questionnaire was filled in. Pearson's correlation was calculated to get insight in the awareness of patients and controls. Comparisons of the relationship between the objective and subjective scores of each individual patient with those of the group of controls were used to allocate each patient into subgroups: overestimators, underestimators and aware patients. Physical and psychological characteristics of these groups were explored. RESULTS: Patients showed weak correlations between the objective and subjective scores of physical activity and appear to have problems in estimating their activity levels (r = -0.27), in contrast to controls who showed strong correlations between the objective and subjective scores (r = 0.66). Comparison of the individual relationships of patients with those of controls showed that 44% of the patients were not aware of their activity level. There were relatively more underestimators (30%) than overestimators (14%). Physical characteristics between the three groups tended to be different. CONCLUSIONS: Patient self-reports about their activity level are relatively inaccurate when compared to objective measurements.

The effects of walking speed on forefoot, hindfoot and ankle joint motion.

BACKGROUND: Foot and ankle joint kinematic differences have been identified between healthy subjects and subjects with various pathologies suffering from foot and ankle impairments. Changes in temporal factors such as walking speed and double stance time are also found in these pathological conditions. As such, in theory, these factors would also influence the kinematics and hence make it difficult to ascertain the effects of the disease on the kinematics. The aim of this study was to analyse foot and ankle kinematics from gait recordings of healthy subjects walking at comfortable and slower speeds. METHODS: Gait patterns of 14 healthy subjects were recorded. The subjects were first asked to walk at a comfortable speed and then at predefined speeds of 75% and 50% of their comfortable walking speed respectively. Temporal variables were calculated. Foot and ankle joint kinematics were determined from marker-recordings. FINDINGS: The subjects walked at mean velocities of 1.28 m/s, 0.97 m/s and 0.65 m/s. With decreasing walking speed the minimum tibio-talar plantar-flexion and maximum hallux dorsi-flexion at toe-off decreased significantly between 3 degrees and 9 degrees. The minimum medial arch at toe-off and minimum midfoot supination at mid-stance were significantly affected by the walking speed. The corresponding individual session differences were small (1 degrees -2 degrees), but the reliability was high and hence the differences were considered clinically relevant. INTERPRETATION: Walking speed significantly affected foot and ankle kinematics. Studies aiming to improve the understanding of the effects of foot and ankle pathologies on foot and ankle kinematics should take the walking speed into account.

Inertial Gait Phase Detection for control of a drop foot stimulator Inertial sensing for gait phase detection.

An Inertial Gait Phase Detection system was developed to replace heel switches and footswitches currently being used for the triggering of drop foot stimulators. A series of four algorithms utilising accelerometers and gyroscopes individually and in combination were tested and initial results are shown. Sensors were positioned on the outside of the upper shank. Tests were performed on data gathered from a subject, sufferer of stroke, implanted with a drop foot stimulator and triggered with the current trigger, the heel switch. Data tested includes a variety of activities representing everyday life. Flat surface walking, rough terrain and carpet walking show 100% detection and the ability of the algorithms to ignore non-gait events such as weight shifts. Timing analysis is performed against the current triggering method, the heel switch. After evaluating the heel switch timing against a reference system, namely the Vicon 370 marker and force plates system. Initial results show a close correlation between the current trigger detection and the inertial sensor based triggering algorithms. Algorithms were tested for stairs up and stairs down. Best results are observed for algorithms using gyroscope data. Algorithms were designed using threshold techniques for lowest possible computational load and with least possible sensor components to minimize power requirements and to allow for potential future implantation of sensor system.

Stop using the Ashworth Scale for the assessment of spasticity.

AIM: Many studies have been performed on the methodological qualities of the (modified) Ashworth Scale but overall these studies seem inconclusive. The aim of this study was to investigate the construct validity and inter-rater reliability of the Ashworth Scale (AS) for the assessment of spasticity in the upper and lower extremities. METHOD: A cross-sectional study on spasticity in the elbow flexors (part 1) and knee extensors (part 2) was carried out. In both parts AS was assessed while muscle activity and resistance were recorded simultaneously in patients with upper motor neuron syndrome. Each patient was measured by three raters. RESULTS: 30 patients participated, 19 in each part of the study. For elbow flexor muscles, AS was not significantly associated with electromyographic parameters, except for rater 2 (rho = 0.66, p<0.01). A significant moderate association was found with resistance (0.54< or = rho < or =0.61, p<0.05). For knee extensors, AS scores were moderately associated with muscle activity (0.56< or = rho < or =0.66, p<0.05) and also with resistance (0.55< or = rho < or =0.87, p<0.05). The intraclass correlation coefficient for absolute agreement was 0.58 for elbow flexors and 0.63 for knee extensors. In linear mixed model analysis, the factor rater appeared to be highly associated with AS. CONCLUSION: The validity and reliability of the AS is insufficient to be used as a measure of spasticity.

Preliminary results of training with gravity compensation of the arm in chronic stroke survivors.

After stroke, arm function can be limited by a reduction in the selectivity of movements, due to involuntary coupling of shoulder abduction and elbow flexion, limiting the ability to reach. Gravity compensation of the arm reduces the required active shoulder abduction torques, which results in a larger range of motion instantaneously. Integration of a motivating rehabilitation game in the training program stimulates motor relearning processes during training. During 6 weeks, 8 chronic stroke survivors received 3 sessions of 30 minutes gravity compensated reach training per week using a rehabilitation game, which was evaluated by assessing motor status and a circle drawing task before and after training. After gravity compensation training, Fugl Meyer scores and the range of motion obtained from the circle drawing task had improved in a seven of the eight chronic stroke survivors. The present findings indicate that gravity compensation in combination with rehab games can be a valuable training modality for stroke rehabilitation.

Influence of gravity compensation on muscle activation patterns during different temporal phases of arm movements of stroke patients.

BACKGROUND: Arm support to help compensate for the effects of gravity may improve functional use of the shoulder and elbow during therapy after stroke, but gravity compensation may alter motor control. OBJECTIVE: To obtain quantitative information on how gravity compensation influences muscle activation patterns during functional, 3-dimensional reaching movements. METHODS: Eight patients with mild hemiparesis performed 2 sets of repeated reach and retrieval movements, with and without unloading the arm, using a device that acted at the elbow and forearm to compensate for gravity. Electromyographic (EMG) patterns of 6 upper extremity muscles were compared during elbow and shoulder joint excursions with and without gravity compensation. RESULTS: Movement performance was similar with and without gravity compensation. Smooth rectified EMG (SRE) values were decreased from 25% to 50% during movements with gravity compensation in 5 out of 6 muscles. The variation of SRE values across movement phases did not differ across conditions. CONCLUSIONS: Gravity compensation did not affect general patterns of muscle activation in this sample of stroke patients, probably since they had adequate function to complete the task without arm support. Gravity compensation did facilitate active arm movement excursions without impairing motor control. Gravity compensation may be a valuable modality in conventional or robot-aided therapy to increase the intensity of training for mildly impaired patients.

Evaluating the effect of electrode location on surface EMG amplitude of the m. erector spinae p. longissimus dorsi.

Variations in surface electromyography (SEMG) amplitude have been shown to be dependent on the dislocation of recording electrodes. Yet no literature is available about the effect of electrode dislocation on SEMG amplitude of the lower back muscles. In this project, the aim was to determine this effect by investigating changes in the SEMG root mean square (RMS), induced by a well-defined dislocation of the recording electrodes. Bipolar SEMG of the longissimus dorsi (LD) muscles was measured in 16 healthy subjects undertaking five functional tasks (standing, forward flexion, re-extension, unsupported sitting and arm/leg lifting), and for eight of those subjects the experiment was repeated within two weeks. Intra-class correlation coefficients (ICCs) were used to show the reliability of the RMS in relation to electrode dislocation, the repeatability of the tasks, and the test-retest reliability. Results showed that: (1) lateral dislocation causes a significant decrease (18%, p<0.001) in RMS; (2) longitudinal dislocation does not change the RMS; and (3) the variability caused by electrode dislocation is comparable to the variability caused by repetitions of tasks or by electrode repositioning. Our conclusion is that positioning in the mediolateral direction should be exact to minimize changes in SEMG amplitude due to dislocation. However, precise longitudinal electrode positioning seems to be less critical in experimental setups which measure the SEMG of the lower back muscles.

Influence of gravity compensation on muscle activity during reach and retrieval in healthy elderly.

INTRODUCTION: Arm support like gravity compensation may improve arm movements during stroke rehabilitation. It is unknown how gravity compensation affects muscle activation patterns during reach and retrieval movements. Since muscle activity during reach is represented by a component varying with movement velocity and a component supposedly counteracting gravity, we hypothesized that gravity compensation decreases the amplitude of muscle activity, but does not affect the pattern. To examine this, we compared muscle activity during well defined movements with and without gravity compensation in healthy elderly. METHODS: Ten subjects performed reach and retrieval movements with and without gravity compensation. Muscle activity of biceps, triceps, anterior, middle and posterior parts of deltoid and upper trapezius was compared between the two conditions. RESULTS: The level of muscle activity was lower with gravity compensation in all muscles, reaching significance in biceps, anterior deltoid and trapezius (p < or = 0.026). The muscle activation pattern did not differ between movements with and without gravity compensation (p > or = 0.662). DISCUSSION: Gravity compensation only influenced the level of muscle activity but not the muscle activation pattern in terms of timing. Future studies should examine if the influence of gravity compensation is comparable for stroke patients. This may stimulate early and intensive training during rehabilitation.

Patient ratings of spasticity during daily activities are only marginally associated with long-term surface electromyography.

AIM: To investigate the association between subjective spasticity ratings and objective spasticity measurement using a new tool for spasticity assessment, that is long-term surface electromyography (sEMG) recordings during daily activities. For monitoring, processing and analysis of this long-term sEMG data, a muscle activity detection algorithm was developed. METHOD: sEMG of the rectus femoris, vastus lateralis, adductor group and semitendinosus of 14 complete spinal-cord-injured patients, in whom voluntary muscle contraction was absent, was recorded continuously during daily activities. Synchronously, subjects stored their activities in a diary and scored their experienced level of spasticity on the Visual Analogue Scale (VAS) for that particular activity. sEMG data were analysed using a high-quality burst-detection algorithm that was developed and validated within this study. Derived sEMG parameters were clustered using principal-component analysis (PCA) and used in a linear mixed model analysis to study their association with VAS. RESULTS: VAS scores appeared significantly associated with the PCA components representing the number and the duration of bursts, but not burst amplitude. Furthermore, VAS scores were associated with the activity performed. The percentage explained variance was, however, low, that is 27-35%. CONCLUSIONS: Patient ratings of the level of spasticity appear poorly associated with spasticity in terms of involuntary muscle activity assessed with long-term sEMG recordings. It is likely that other factors such as pain and cognitions are also incorporated in these patient ratings. Clinicians are therefore strongly advised to perform complementary objective assessments using long-term sEMG recordings.

Muscle activation patterns of knee flexors and extensors during passive and active movement of the spastic lower limb in chronic stroke patients.

The aim of this study was to describe the characteristics of spasticity, quantified as muscle activity during stretch, during passive and active movement. For this cross sectional study 19 stroke patients with spasticity in the lower limb were recruited. Reflex activity was studied with surface electromyography of knee flexor and extensor muscles during passive and active movement of the lower leg. On both the affected and unaffected side, root mean square values of the knee extensor muscles, while stretched, were higher during active than during passive movement (p<0.05). For the vastus lateralis (VL) the correlation was moderate (rho=0.54, p=0.022), for the rectus femoris (RF) high (rho=0.83, p<0.001). For the semitendinosus (ST) the correlation was low (rho=0.27) and not significant. During active movement the correlation between VL activity and activity of the antagonist ST, as an indicator for co-contraction of the affected muscles, was marked (rho=0.73, p=0.001). A moderate negative correlation was found between reflex activity of RF during passive stretch and the active range of motion (rho=-0.51, p=0.027). The results show that a passive stretch test alone is insufficient either as assessment method for spasticity during active motor tasks or as a measure for motor control.