Relation between stimulation characteristics and clinical outcome in studies using electrical stimulation to improve motor control of the upper extremity in stroke

Objective: Electrical stimulation can be applied in a variety of ways to the hemiparetic upper extremity following stroke. The aim of this review is to explore the relationship between characteristics of stimulation and the effect of electrical stimulation on the recovery of upper limb motor control following stroke. Methods: A systematic literature search was performed to identify clinical trials evaluating the effect of electrical stimulation on motor control. The reported outcomes were examined to identify a possible relationship between the reported effect and the following characteristics: duration of stimulation, method of stimulation, setting of stimulation parameters, target muscles and stage after stroke. Results: Nineteen clinical trials were included, and the results of 22 patient groups were evaluated. A positive effect of electrical stimulation was reported for 13 patient groups. Positive results were more common when electrical stimulation was triggered by voluntary movement rather than when non-triggered electrical stimulation was used. There was no relation between the effect of electrical stimulation and the other characteristics examined. Conclusion: Triggered electrical stimulation may be more effective than non-triggered electrical stimulation in facilitating upper extremity motor recovery following stroke. It appears that the specific stimulus parameters may not be crucial in determining the effect of electrical stimulation

Predictive value of fear avoidance in developing chronic neck pain disability: consequences for clinical decision making

Objective\ud To improve clinical decision making in posttraumatic neck pain by investigating the additional value of fear-avoidance variables in predicting chronic neck pain disability.\ud \ud Design\ud An inception cohort with baseline assessment 1 week posttrauma and outcome assessment 24 weeks posttrauma. Predictive factors include pain intensity, Neck Disability Index (NDI), catastrophizing, fear of movement (Tampa Scale for Kinesiophobia [TSK]), and avoidance muscle behavior.\ud \ud Setting\ud Hospital emergency department of a general hospital.\ud \ud Participants\ud A consecutive sample of 90 people reporting of pain in neck or head region after a motor vehicle collision. Eighty-two subjects (91.1%) of the sample provided 24-week follow-up on the outcome.\ud \ud Interventions\ud Not applicable.\ud \ud Main outcome measure\ud The NDI assessing physical disability of subjects with neck pain.\ud \ud Results\ud By using a combination of the baseline NDI and TSK, it appears to be possible to predict chronic disability with a probability of 54.3% (95% confidence interval [CI], 35.2%–72.3%) after entering the NDI (cutoff, 15) as a first test, and with a probability of 83.3% (95% CI, 70.3%–91.3%) after entering the TSK (cutoff, 40) in a second test.\ud \ud Conclusions\ud A simple rating of baseline neck pain disability within a week of the trauma, separately or in combination with a test for fear of movement, can be used to predict future outcome. Patients showing fear of movement can be offered an intervention that focuses on reduction of this fear.\ud \u

Cervical muscle dysfunction in the chronic whiplash associated disorder grade

FROM ABSTRACT Study Design. Surface electromyography measurements of the upper trapezius muscles were performed in patients with a chronic whiplash-associated disorder Grade 2 and those with nonspecific neck pain. Objective. To determine the etiologic relation between acceleration-deceleration trauma and the presence of cervical muscle dysfunction in the chronic stage of whiplash-associated disorder. Summary of Background Information. From a biopsychosocial perspective, the acceleration-deceleration trauma in patients with whiplash-associated disorder is not regarded as a cause of chronicity of neck pain, but rather as a risk factor triggering response systems that contribute to the maintenance of neck pain. One of the contributing factors is dysfunction of the cervical muscles. Considering the limited etiologic significance of the trauma, it is hypothesized that in patients with neck pain, there are no differences in muscle activation patterns between those with and those without a history of an acceleration-deceleration trauma. Methods. Muscle activation patterns, expressed in normalized smooth rectified electromyography levels of the upper trapezius muscles, in patients with whiplash-associated disorder Grade 2 were compared with those of patients with nonspecific neck pain. The outcome parameters were the mean level of muscle activity before and after a physical exercise, the muscle reactivity in response to the exercise, and the timedependent behavior of muscle activity after the exercise. Results

Chronic neck pain disability due to an acute whiplash injury

Several theories about musculoskeletal pain syndromes such as whiplash-associated disorder (WAD) suggest that pain and muscle activity interact and may contribute to the chronicity of symptoms. Studies using surface electromyography (sEMG) have demonstrated abnormal muscle activation patterns of the upper trapezius muscles in the chronic stage of WAD (grade II). There are, however, no studies that confirm that these muscle reactions are initiated in the acute stage of WAD, nor that these muscle reactions persist in the transition from acute neck pain to chronic neck pain disability.\ud \ud We analyzed the muscle activation patterns of the upper trapezius muscles in a cohort of 92 subjects with acute neck pain due to a motor vehicle accident (MVA). This cohort was followed up in order to evaluate differences in muscular activation patterns between subjects who have recovered and those subjects who have not recovered following an acute WAD and developed chronic neck pain. sEMG parameters were obtained at 1, 4, 8, 12, and 24 weeks after an MVA. The level of muscle reactivity (the difference in pre- and post-exercise EMG levels) and the level of muscle activity during an isometric and a dynamic task were used as EMG parameters.\ud \ud The results revealed no elevated muscle reactivity either in the acute stage, or during the follow-up period. The results of both the isometric and dynamic task, showed statistically significant different EMG levels between four neck pain disability subgroups (analysis of variance reaching P-levels of 0.000), with an inverse relationship between the level of neck pain disability and EMG level. Furthermore, follow-up assessments of the EMG level during these two tasks, did not show a time related change.\ud \ud In conclusion, in subjects with future disability, the acute stage is characterized by a reorganization of the muscular activation of neck and shoulder muscles, possibly aimed at minimizing the use of painful muscles. This change of motor control, is in accordance with both the (neurophysiological) ‘pain adaptation model’ and (cognitive behavioral) ‘fear avoidance model’\u

Cervical Muscle Dysfunction in the Chronic Whiplash Associated Disorder Grade II (WAD-II)

Study Design: In a cross-sectional study, surface electromyography\ud measurements of the upper trapezius\ud muscles were obtained during different functional tasks in\ud patients with a chronic whiplash associated disorder\ud Grade II and healthy control subjects. - \ud Objectives: To investigate whether muscle dysfunction\ud of the upper trapezius muscles, as assessed by surface\ud electromyography, can be used to distinguish patients\ud with whiplash associated disorder Grade II from\ud healthy control subjects. - \ud Summary of Background Information: In the whiplash\ud associated disorder, there is need to improve the diagnostic\ud tools. Whiplash associated disorder Grade II is\ud characterized by the presence of “musculoskeletal signs.”\ud Surface electromyography to assess these musculoskeletal\ud signs objectively may be a useful tool. - \ud Methods: Normalized smoothed rectified electromyography\ud levels of the upper trapezius muscles of patients\ud with whiplash associated disorder Grade II (n 5 18) and\ud healthy control subjects (n 5 19) were compared during\ud three static postures, during a unilateral dynamic manual\ud exercise, and during relaxation after the manual exercise.\ud Coefficients of variation were computed to identify the\ud measurement condition that discriminated best between\ud the two groups. - \ud Results: The most pronounced differences between\ud patients with whiplash associated disorder Grade II and\ud healthy control subjects were found particularly in situations\ud in which the biomechanical load was low. Patients\ud showed higher coactivation levels during physical exercise\ud and a decreased ability to relax muscles after physical\ud exercise. - \ud Conclusions: Patients with whiplash associated disorder\ud Grade II can be distinguished from healthy control\ud subjects according to the presence of cervical muscle\ud dysfunction, as assessed by surface electromyography of\ud the upper trapezius muscles. Particularly the decreased\ud ability to relax the trapezius muscles seems to be a promising\ud feature to identify patients with whiplash associated\ud disorder Grade II. Assessment of the muscle (dys)function\ud by surface electromyography offers a refinement of the\ud whiplash associated disorder classification and provides\ud an indication to a suitable therapeutic approach. [Key\ud words: whiplash associated disorder, muscle dysfunction,\ud surface electromyography, upper trapezius muscle,\ud static, dynamic, relaxation

Cervical Muscle Dysfunction in Chronic Whiplash-Associated Disorder Grade 2: The Relevance of the Trauma

Study Design. Surface electromyography measurements of the upper trapezius muscles were performed in patients with a chronic whiplash-associated disorder Grade 2 and those with nonspecific neck pain. Objective. To determine the etiologic relation between acceleration–deceleration trauma and the presence of cervical muscle dysfunction in the chronic stage of whiplash-associated disorder. Summary of Background Information. From a biopsychosocial perspective, the acceleration–deceleration trauma in patients with whiplash-associated disorder is not regarded as a cause of chronicity of neck pain, but rather as a risk factor triggering response systems that contribute to the maintenance of neck pain. One of the contributing factors is dysfunction of the cervical muscles. Considering the limited etiologic significance of the trauma, it is hypothesized that in patients with neck pain, there are no differences in muscle activation patterns between those with and those without a history of an acceleration–deceleration trauma. Methods. Muscle activation patterns, expressed in normalized smooth rectified electromyography levels of the upper trapezius muscles, in patients with whiplash-associated disorder Grade 2 were compared with those of patients with nonspecific neck pain. The outcome parameters were the mean level of muscle activity before and after a physical exercise, the muscle reactivity in response to the exercise, and the time-dependent behavior of muscle activity after the exercise. Results. There were no statistical significant differences in any of the outcome parameters between patients with whiplash-associated disorder Grade 2 and those with nonspecific neck pain. There was only a tendency of higher muscle reactivity in patients with whiplash-associated disorder Grade 2. Conclusions. It appears that the cervical muscle dysfunction in patients with chronic whiplash-associated disorder Grade 2 is not related to the specific trauma mechanism. Rather, cervical muscle dysfunction appears to be a general sign in diverse chronic neck pain syndrome