Johan Swanik Rietman

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⩽ rho ⩽0.61, p<0.05). For knee extensors, AS scores were moderately associated with muscle activity (0.56⩽ rho ⩽0.66, p<0.05) and also with resistance (0.55⩽ rho ⩽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.

Vibro- and Electrotactile User Feedback on Hand Opening for Myoelectric Forearm Prostheses

Many of the currently available myoelectric forearm prostheses stay unused because of the lack of sensory feedback. Vibrotactile and electrotactile stimulation have high potential to provide this feedback. In this study, performance of a grasping task is investigated for different hand opening feedback conditions on 15 healthy subjects and validated on three patients. The opening of a virtual hand was controlled by a scroll wheel. Feedback about hand opening was given via an array of eight vibrotactile or electrotactile stimulators placed on the forearm, relating to eight hand opening positions. A longitudinal and transversal orientation of the array and four feedback conditions were investigated: no feedback, visual feedback, feedback through vibrotactile or electrotactile stimulation, and addition of an extra stimulator for touch feedback. No influence of array orientation was shown for all outcome parameters (duration of the task, the percentage of correct hand openings, the mean position error, and the percentage deviations up to one position). Vibrotactile stimulation enhances the performance compared to the nonfeedback conditions. The addition of touch feedback further increases the performance, but at the cost of an increased duration. The same effects were found for the patient group, but the task duration was around 25% larger.

Back Muscle Activation Patterns in Chronic Low Back Pain During Walking: A Guarding Hypothesis

Objectives:To investigate whether patients with chronic low back pain (CLBP) show “guarded” movements during walking. It is hypothesized that guarding will be reflected by increased lumbar muscle activity during all periods of stride and secondary, relatively lesser relaxation during periods of swing compared with double support. Furthermore, it is hypothesized that higher levels of perceived fear and disability are related to increased muscle activity and less relative relaxation. Materials and Methods:In a cross-sectional study 63 patients with CLBP and 33 healthy controls walked on a treadmill at 3.8 km/h. Surface electromyography (sEMG) data of the erector spinae were obtained and smoothed rectified sEMG (SRE) values were calculated per period of swing and double support. The ratio of SRE values in swing to double support was used as a measure of relative relaxation (SRE ratio). In addition, the relationship between SRE values, the Roland Morris Disability Questionnaire, and the Tampa Scale for Kinesiophobia was analyzed in patients with CLBP. Results:Mean SRE values were significantly higher in patients with CLBP than in controls both during periods of double support and swing. SRE ratios were not significantly different between groups. Results showed no influence of disability or fear of movement on either SRE values or ratios. Discussion:In patients with CLBP, increased lumbar muscle activity during all periods of stride, with comparable alteration between swing and double support, suggests difficulties with total muscle relaxation. On the basis of this evaluation, it is concluded that patients with CLBP show a guarding mechanism during walking. No relationship is found between perceived fear, disability, and muscle activity.

Adaptation Strategies of the Lower Extremities of Patients With a Transtibial or Transfemoral Amputation During Level Walking: A Systematic Review

OBJECTIVE To describe adaptation strategies in terms of joint power or work in the amputated and intact leg of patients with a transtibial (TT) or transfemoral (TF) amputation. DATA SOURCES MEDLINE, CINAHL, Physiotherapy Evidence Database, Embase, and the Cochrane Register of Controlled Trials were searched. Studies were collected up to November 1, 2010. Reference lists were additionally scrutinized. STUDY SELECTION Studies were included when they presented joint power or work and compared (1) the amputated and intact legs, (2) the amputated leg and a referent leg, or (3) the intact leg and a referent leg. Eligibility was independently assessed by 2 reviewers. A total of 13 articles were identified. DATA EXTRACTION Data extraction was performed using standardized forms of the Cochrane Collaboration. Methodologic quality was independently assessed using the Downs and Black instrument by 2 reviewers. The possibility of data pooling was examined. Significant differences found in studies that could not be pooled are also presented. DATA SYNTHESIS Significant results (P<.05). For work TT, for the concentric work total stance phase knee, the amputated was less than the intact/referent side, and the referent was less than the intact side. For the eccentric knee extensor (K1) phase, the amputated was less than the intact side, and the intact was greater than the referent side. For the concentric knee extensor (K2) phase, the amputated/referent was less than the intact side. For the concentric work total stance phase hip, the amputated/intact was greater than the referent side. For the concentric hip extensor (H1) phase, the amputated/intact was greater than the referent side. For power TT, for the peak power generation stance phase knee, the amputated was less than the referent side. For peak power generation swing phase knee, the amputated was less than the referent side. For the eccentric knee flexor (K4) phase, the amputated was less than the intact side. For the eccentric hip flexor (H2) phase, the amputated was greater than the intact side. For work TF, for the concentric plantar flexor (A2) phase, the referent was less than the intact side. For the H1 phase, the referent was less than the intact side. For the H2 phase, the amputated was greater than the intact/referent side, and the referent was greater than the intact side. For power TF, for the K2 phase, the referent was less than the intact side. Sensitivity analysis did not alter the conclusions. CONCLUSIONS Adaptations were seen in the amputated and intact legs. TT and TF use remarkably similar adaptation strategies at the level of the hip to compensate for the loss of plantar flexion power and facilitate forward progression. At the knee level, adaptations differed between TT and TF.

Circle drawing as evaluative movement task in stroke rehabilitation: an explorative study

BackgroundThe majority of stroke survivors have to cope with deficits in arm function, which is often measured with subjective clinical scales. The objective of this study is to examine whether circle drawing metrics are suitable objective outcome measures for measuring upper extremity function of stroke survivors.MethodsStroke survivors (n = 16) and healthy subjects (n = 20) drew circles, as big and as round as possible, above a table top. Joint angles and positions were measured. Circle area and roundness were calculated, and synergistic movement patterns were identified based on simultaneous changes of the elevation angle and elbow angle.ResultsStroke survivors had statistically significant lower values for circle area, roundness and joint excursions, compared to healthy subjects. Stroke survivors moved significantly more within synergistic movement patterns, compared to healthy subjects. Strong correlations between the proximal upper extremity part of the Fugl-Meyer scale and circle area, roundness, joint excursions and the use of synergistic movement patterns were found.ConclusionsThe present study showed statistically significant differences in circle area, roundness and the use of synergistic movement patterns between healthy subjects and stroke survivors. These circle metrics are strongly correlated to stroke severity, as indicated by the proximal upper extremity part of the FM score.In clinical practice, circle area and roundness can give useful objective information regarding arm function of stroke survivors. In a research setting, outcome measures addressing the occurrence of synergistic movement patterns can help to increase understanding of mechanisms involved in restoration of post stroke upper extremity function.

Influence of gravity compensation training on synergistic movement patterns of the upper extremity after stroke, a pilot study

BackgroundThe majority of stroke patients have to cope with impaired arm function. Gravity compensation of the arm instantaneously affects abnormal synergistic movement patterns. The goal of the present study is to examine whether gravity compensated training improves unsupported arm function.MethodsSeven chronic stroke patients received 18 half-hour sessions of gravity compensated reach training, in a period of six weeks. During training a motivating computer game was played. Before and after training arm function was assessed with the Fugl-Meyer assessment and a standardized, unsupported circle drawing task. Synergistic movement patterns were identified based on concurrent changes in shoulder elevation and elbow flexion/extension angles.ResultsMedian increase of Fugl-Meyer scores was 3 points after training. The training led to significantly increased work area of the hemiparetic arm, as indicated by the normalized circle area. Roundness of the drawn circles and the occurrence of synergistic movement patterns remained similar after the training.ConclusionsA decreased strength of involuntary coupling might contribute to the increased arm function after training. More research is needed to study working mechanisms involved in post stroke rehabilitation training. The used training setup is simple and affordable and is therefore suitable to use in clinical settings.

Stiffness Feedback for Myoelectric Forearm Prostheses Using Vibrotactile Stimulation

The ability to distinguish object stiffness is a very important aspect in object handling, but completely lacking in current myoelectric prostheses. In human hands both tactile and proprioceptive sensory information are required for stiffness determination. Therefore, it was investigated whether it is possible to distinguish object stiffness with vibrotactile feedback of hand opening and grasping force. Three configurations consisting of an array of coin motors and a single miniature vibrotactile transducer were investigated. Ten healthy subjects and seven subjects with upper limb loss due to amputation or congenital defects performed virtual grasping tasks, in which they controlled hand opening and grasping force. They were asked to determine the stiffness of a grasped virtual object from four options. With hand opening feedback alone or in combination with grasping force feedback, correct stiffness determination was achieved in around 60% of the cases and significantly higher than the 25% achieved without feedback or grasping force feedback alone. Despite the equal performance results, the combination of hand opening and grasping force feedback was preferred by the subjects over the hand opening feedback alone. No differences between feedback configurations and between subjects with upper limb loss and healthy subjects were found.

The effect of Arm Support combined with rehabilitation games on upper-extremity function in subacute stroke: A randomized controlled trial

Background. Use of rehabilitation technology, such as (electro)mechanical devices or robotics, could partly relieve the increasing strain on stroke rehabilitation caused by an increasing prevalence of stroke. Arm support (AS) training showed improvement of unsupported arm function in chronic stroke. Objective. To examine the effect of weight-supported arm training combined with computerized exercises on arm function and capacity, compared with dose-matched conventional reach training in subacute stroke patients. Methods. In a single-blind, multicenter, randomized controlled trial, 70 subacute stroke patients received 6 weeks of training with either an AS device combined with computerized exercises or dose-matched conventional training (CON). Arm function was evaluated pretraining and posttraining by Fugl-Meyer assessment (FM), maximal reach distance, Stroke Upper Limb Capacity Scale (SULCS), and arm pain via Visual Analogue Scale, in addition to perceived motivation by Intrinsic Motivation Inventory posttraining. Results. FM and SULCS scores and reach distance improved significantly within both groups. These improvements and experienced pain did not differ between groups. The AS group reported higher interest/enjoyment during training than the CON group. Conclusions. AS training with computerized exercises is as effective as conventional therapy dedicated to the arm to improve arm function and activity in subacute stroke rehabilitation, when applied at the same dose.

Detection of the onset of gait initiation using kinematic sensors and EMG in transfemoral amputees

In this study we determined if detection of the onset of gait initiation in transfemoral amputees can be useful for voluntary control of upper leg prostheses. From six transfemoral amputees inertial sensor data and EMG were measured at the prosthetic leg during gait initiation. First, initial movement was detected from the inertial sensor data. Subsequently it was determined whether EMG could predict initial movement before detection based on the inertial sensors with comparable consistency as the inertial sensors. From the inertial sensors the initial movement can be determined. If the prosthetic leg leads, the upper leg accelerometer data was able to detect initial movement best. If the intact leg leads the upper leg gyroscope data performed best. Inertial sensors at the upper leg in general showed detections at the same time or earlier than those at the lower leg. EMG can predict initial movement up to a 138 ms in advance, when the prosthetic leg leads. One subject showed consistent EMG onset up to 248 ms before initial movement in the intact leg leading condition. A new method to detect initial movement from inertial sensors was presented and can be useful for additional prosthetic control. EMG measured at the prosthetic leg can be used for prediction of gait initiation when the prosthetic leg is leading, but for the intact leg leading condition this will not be of additional value.

Comparison of muscle activity patterns of transfemoral amputees and control subjects during walking

BackgroundOnly few studies have looked at electromyography (EMG) during prosthetic gait. Differences in EMG between normal and prosthetic gait for stance and swing phase were never separately analyzed. These differences can give valuable information if and how muscle activity changes in prosthetic gait.MethodsIn this study EMG activity during gait of the upper leg muscles of six transfemoral amputees, measured inside their own socket, was compared to that of five controls. On and off timings for stance and swing phase were determined together with the level of co-activity and inter-subject variability.Results and conclusionsGait phase changes in amputees mainly consisted of an increased double support phase preceding the prosthetic stance phase. For the subsequent (pre) swing phase the main differences were found in muscle activity patterns of the prosthetic limb, more muscles were active during this phase and/or with prolonged duration. The overall inter-subject variability was larger in amputees compared to controls.