Multimodal and widespread somatosensory abnormalities in persistent shoulder pain in the first 6 months after stroke: an exploratory study.

OBJECTIVE: To explore the role of multimodal and widespread somatosensory abnormalities in the development of persistent poststroke shoulder pain (pPSSP) in the first 6 months after stroke. DESIGN: Prospective inception cohort study. SETTING: Stroke units of 2 teaching hospitals. PARTICIPANTS: The data of a strict selection of patients (N=31) with a clinical diagnosis of stroke were analyzed. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The development of pPSSP within the first 6 months after stroke. Bilateral sensation and pain thresholds at 3 (t1) and 6 (t2) months, and conditioned pain modulation (CPM) at 3 months after stroke. Clinical examination within 2 weeks after stroke (t0), at t1, and at t2. RESULTS: pPSSP (n=9) was associated with increased sensation and pain threshold ratios at the affected side (t1, t2), and with reduced cold pain tolerance at the unaffected side (t1). CPM was not different from patients without pPSSP (n=22). Notably, in patients with pPSSP reporting increased sensation on clinical examination, multiple body sites across multiple stimulus modalities were involved, and increased sensation persisted from t1 to t2. CONCLUSIONS: pPSSP in the first 6 months after stroke was associated with somatosensory loss to both innocuous and noxious stimuli (affected side). In addition, pPSSP was associated with sensitization to cold pain (unaffected side) and with widespread sensitization to multimodal innocuous stimuli (affected side). The results support the notion that central somatosensory sensitization could play an important role in the development of pPSSP, the maintenance of pPSSP, or both.

Persistent shoulder pain in the first 6 months after stroke: results of a prospective cohort study.

OBJECTIVE: To identify factors associated with persistent poststroke shoulder pain (pPSSP) in the first 6 months after stroke. DESIGN: Prospective inception cohort study. SETTING: Stroke units of 2 teaching hospitals. PARTICIPANTS: Patients (N=31) with a clinical diagnosis of stroke. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The development of pPSSP within the first 6 months after stroke. Clinical assessment of motor, somatosensory, cognitive, emotional, and autonomic functions, undertaken within 2 weeks (t0), at 3 months (t1), and at 6 months (t2) after stroke. RESULTS: Patients with pPSSP (n=9) were compared with patients without pPSSP (n=22). Bivariate logistic regression analyses showed that pPSSP was significantly associated with impaired voluntary motor control (t0, t1, t2), diminished proprioception (t0, t1), tactile extinction (t0), abnormal sensation (t1, t2), spasticity of the elbow flexor muscles (t1, t2), restricted range of motion (ROM) for both shoulder abduction (t2) and shoulder external rotation (t1, t2), trophic changes (t1), and type 2 diabetes mellitus (t0). CONCLUSIONS: These findings suggest a multifactorial etiology of pPSSP. The association of pPSSP with restricted, passive, pain-free ROM and signs indicative of somatosensory sensitization may implicate a vicious cycle of repetitive (micro)trauma that can establish itself rapidly after stroke. Intervention should therefore be focused on maintaining and restoring joint ROM as well as preventing injury and somatosensory sensitization. In this perspective, strategies that aim to intervene simultaneously at various levels of function can be expected to be more effective than treatment directed at merely 1 level.

The use of the analytic hierarchy process to aid decision making in acquired equinovarus deformity.

OBJECTIVE: To increase the transparency of decision making about treatment in patients with equinovarus deformity poststroke. DESIGN: The analytic hierarchy process (AHP) was used as a structured methodology to study the subjective rationale behind choice of treatment. SETTING: An 8-hour meeting at a centrally located rehabilitation center in The Netherlands, during which a patient video was shown to all participants (using a personal computer and a large screen) and the patient details were provided on paper. PARTICIPANTS: A panel of 10 health professionals from different backgrounds. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The performance of the applicable treatments on outcome, impact, comfort, cosmetics, daily effort, and risks and side effects of treatment, as well as the relative importance of criteria in the choice of treatment. RESULTS: According to the model, soft-tissue surgery (.413) ranked first as the preferred treatment, followed by orthopedic footwear (.181), ankle-foot orthosis (.147), surface electrostimulation (.137), and finally implanted electrostimulation (.123). Outcome was the most influential consideration affecting treatment choice (.509), followed by risk and side effects (.194), comfort (.104), daily effort (.098), cosmetics (.065), and impact of treatment (.030). CONCLUSIONS: Soft-tissue surgery was judged best on outcome, daily effort, comfortable shoe wear, and cosmetically acceptable result and was thereby preferred as a treatment alternative by the panel in this study. In contrast, orthosis and orthopedic footwear are usually preferred in daily practice. The AHP method was found to be suitable methodology for eliciting subjective opinions and quantitatively comparing treatments in the absence of scientific evidence.

A preliminary economic evaluation of percutaneous neuromuscular electrical stimulation in the treatment of hemiplegic shoulder pain.

OBJECTIVE: The objective of this study was to compare the cost-effectiveness of various treatment modalities for hemiplegic shoulder pain. DESIGN: A stage II economic evaluation. MAIN OUTCOME MEASURES: Incremental cost effectiveness ratio of P-NMES, compared to slings and anti-inflammatory injections. RESULTS: The incremental cost effectiveness ratio (ICER) of p-NMES, compared to anti-inflammatory injections is 6,061 euro(+/-3,285). The incremental cost of the first quality-adjusted life year after implantation of the P-NMES device compared to anti-inflammatory injections is 33,007 euro (+/-5,434). This decreases to approximately 7,000 euro after 5 years, and to approximately 5,000 euro after 10 survival years. CONCLUSION: In this early evaluation, P-NMES seems to be cost-effective according to known guidelines. Treatment with P-NMES is recommended for patients with chronic HSP.

Towards a mechanism-based view on post-stroke shoulder pain: theoretical considerations and clinical implications.

The assessment and treatment of post-stroke shoulder pain (PSSP) is largely based on the assumption that pain is due to biomechanical alterations within the shoulder joint after stroke. However, current treatment often provides limited pain relief, leading to a considerable number of patients with persistent pain. This suggests that PSSP may not be merely due to simple nociception from the shoulder joint. A better understanding of the neurophysiological mechanisms underlying the development and perpetuation of PSSP is needed. Here, a theoretical framework for presumed PSSP mechanisms and their assessment is presented based on key concepts applied in pain research. This theoretical framework assumes that although pain may be localized in one region of the body, the mechanisms causing pain may occur at any level of the somatosensory neuro-axis. Detailed assessment of pain complaints and somatosensory abnormalities should, therefore, be a key element in clinical PSSP research. Studies aiming to further characterize somatosensory functions in patients with PSSP (initially) need to take a broad methodological approach including both clinical as well as more experimental pain research tools, such as quantitative sensory testing. A better understanding of pain mechanisms may explain why persistent PSSP and unsatisfactory pain relief are common despite active prevention and treatment strategies and may provide a basis for improved clinical management of PSSP.

Changes in muscle activation after reach training with gravity compensation in chronic stroke patients.

The objective of this study is to examine the effect of gravity compensation training on reaching and underlying changes in muscle activation. In this clinical trial, eight chronic stroke patients with limited arm function received 18 sessions (30 min) of gravity-compensated reach training (during 6 weeks) in combination with a rehabilitation game. Before and after training, unsupported reach (assessing maximal distance, joint angles and muscle activity of eight shoulder and elbow muscles) and the Fugl-Meyer assessment were compared. After training, the maximal reach distance improved significantly by 3.5% of arm length, together with increased elbow extension (+9.2°) and increased elbow extensor activity (+68%). In some patients, a reduced cocontraction of biceps and anterior deltoid was also involved, although this was not significant on group level. Improvements in unsupported reach after gravity compensation training in chronic stroke patients with mild to severe hemiparesis were mainly accompanied by increased activation of prime movers at the elbow, although in some patients, improved selective joint control may also have been involved. Gravity compensation seems to be a suitable way to provide active, task-specific treatment, without the need for high-tech devices. Further research on a larger scale, including control groups and combinations of arm support with functional hand training, is essential to enhance the potential of arm support to complement poststroke arm rehabilitation.

Improving walking capacity by surgical correction of equinovarus foot deformity in adult patients with stroke or traumatic brain injury: a systematic review.

OBJECTIVE: Equinovarus foot deformity following stroke or traumatic brain injury compromises walking capacity, interfering with activities of daily living. In soft-tissue surgery the imbalanced muscles responsible for the deviant position of the ankle and foot are lengthened, released and/or transferred. However, knowledge about the effectiveness of surgical correction is limited. The aim of the present study was to carry out a systematic review of the literature to assess the effects of surgical correction of equinovarus foot deformity in patients with stroke or traumatic brain injury. METHODS: A systematic search of full-length articles in the English, German or Dutch languages published from 1965 to March 2011 was performed in PubMed, EMBASE, CINAHL, Cochrane and CIRRIE. The identified studies were analysed following the International Classification of Functioning, Disability and Health criteria. RESULTS: A total of 15 case series, case control and historically controlled studies (CEBM level 4) were identified, suggesting that surgical correction of equinovarus foot deformity is a safe procedure that is effective in terms of re-obtaining a balanced foot position, improving walking capacity and diminishing the need for orthotic use. DISCUSSION: Further validation of surgical correction of equinovarus foot deformity following stroke or traumatic brain injury is required, using higher level study designs with validated assessment tools. Comparing surgical techniques with other interventions is necessary to generate evidence upon which treatment algorithms could be based.

Classifying post-stroke shoulder pain: can the DN4 be helpful?

The etiology of post-stroke shoulder pain (PSSP) is largely unclear and may involve both nociceptive and neuropathic mechanisms. No gold standard is present for PSSP diagnosis. The neuropathic pain diagnostic questionnaire (DN4), was originally developed to identify neuropathic pain in the clinical context. In this study we used the DN4 to categorize PSSP patients and compared symptoms and signs suggestive of either nociceptive or neuropathic pain. Pain complaints and sensory functions were compared between patients with chronic PSSP scoring at least four (DN4+, n=9) or less than four (DN4-, n=10) on the DN4. Pain was assessed using a numeric rating scale and the McGill pain questionnaire. Sensory functions were assessed using clinical examination and quantitative sensory testing combined with a cold pressor test. Patients classified as DN4+ reported constant pain, higher pain intensity, a higher impact of pain on daily living, more frequent loss of cold sensation, reduced QST thresholds at the unaffected side and increased QST thresholds at the affected side. Notably, several symptoms and signs suggestive of either neuropathic or nociceptive pain corresponded to the subgroups DN4+ and DN4- respectively. However, since the pathophysiological mechanisms remain unclear and none of the sensory signs could be exclusively related to either DN4+ or DN4-, PSSP prognosis and treatment should not be solely based on the DN4. Nonetheless, a thorough assessment of neuropathic and nociceptive pain complaints and somatosensory functions should be included in the diagnostic work-up of PSSP.

Altered cortical somatosensory processing in chronic stroke: A relationship with post-stroke shoulder pain.

Post-stroke shoulder pain (PSSP), traditionally regarded as purely nociceptive pain, is often persistent and the mechanisms underlying the pain complaints are not well understood. This explorative study is the first to address the possible changes in cortical somatosensory processing in patients with PSSP. Cortical potentials were recorded following intracutaneous electrostimulaton in stroke patients with chronic PSSP (n= 6), pain-free stroke patients (PF, n=14) and healthy controls (HC, n=20) using EEG. Amplitudes and latencies of both sensory discriminative (N90) as well as cognitive evaluative (N150, P200, the N150-P200 peak-to-peak difference and P300) evoked potential components were evaluated. Stroke was associated with reduced N150 and P300 amplitudes and increased N90, N150 and P300 latencies at both sides. Compared to PF and HC, the P200 and N150-P200 latencies were increased in PSSP patients after stimulation at both sides, even when comparing subgroups with similar lesion size and location. Stroke was associated with reduced sensory-discriminative as well as with reduced cognitive-evaluative cortical somatosensory processing. This reduction was more pronounced in patients with PSSP and may be related to the central effects of persistent nociceptive pain.

Somatosensory symptoms and signs and conditioned pain modulation in chronic post-stroke shoulder pain.

UNLABELLED: Persistent shoulder pain is a common complication after stroke. Its etiology and underlying mechanisms are not well understood and treatment is generally unsatisfactory. The objective of this study was to assess the role of central sensitization and disinhibition in chronic stroke patients with chronic PSSP (n = 19), pain-free stroke patients (n = 29), and healthy controls (n = 23). Positive and negative somatosensory symptoms and signs were assessed using clinical examination and electrical and mechanical quantitative sensory testing (QST). Conditioned pain modulation (CPM) was assessed by comparing QST thresholds before and after applying a cold pressor test. Sensory abnormalities were more frequently observed and more severe in patients with PSSP, including positive signs such as allodynia at the affected side and generalized hyperalgesia at the unaffected side. CPM was similar in stroke patients and healthy controls. This study showed that chronic PSSP was associated with several positive and negative somatosensory signs, implicating a role for central sensitization and possibly for disinhibition. Since the causal relationship remains unclear, and may be related to either neuroplasticity induced by ongoing nociception as well as to the neuropathic brain lesion, prospective studies are warranted. PERSPECTIVE: The assessment of somatosensory symptoms and signs and endogenous pain modulation demonstrated a role for central sensitization and possibly for disinhibition in chronic PSSP. Prevention and treatment of PSSP could benefit from a more detailed analysis of both peripheral and central pain mechanisms.

Feasibility of web-based decision aids in neurological patients.

Decision aids (DAs) may be helpful in improving patients' participation in medical decision-making. We investigated the potential for web-based DAs in a rehabilitation population. Two self-administered DAs focused on the treatment of acquired ankle-foot impairment in stroke and the treatment of arm-hand function in cervical spinal cord injury (SCI). Data collection comprised a telephone interview and a self-reported paper questionnaire. Of the patients who agreed to participate, 39 stroke patients (44%) and 38 patients with SCI (78%) returned a questionnaire. More than 75% of patients expressed a need for more information about the treatment of disease-related impairment. The DAs were highly appreciated by both patient groups. Nearly all patients expressed a positive attitude towards the use of the web-based DAs in general practice. The DAs had a positive effect on the knowledge about the treatment alternatives in the stroke patients (P = 0.001), although not in the patients with SCI. The DAs reduced patients' conflict about treatment (P < 0.05). The effect of the DAs on patients' desired role in decision-making was limited. Web-based aids are feasible in the rehabilitation population with access to a computer and can improve the knowledge gaps in patients.

Neuromuscular stimulation after stroke: from technology to clinical deployment.

Since the early 1960s, electrical or neuromuscular electrical stimulation (NMES) has been used to support the rehabilitation of stroke patients. One of the earliest applications of NMES included the use of external muscle stimulation to correct drop-foot after stroke. During the last few decades various clinical applications have been used for the upper and lower limb. Despite a growing body of literature on the use of NMES, its application in stroke is still limited to a few clinical groups that provide dedicated clinical services. Some explanations for the limited use are the sometimes conflicting clinical evidence, the size of the effects or the complicated use of the technology itself. This review points out three directions for future research. First, we need to expand our knowledge on brain plasticity and the use of different electrical stimulation strategies to modulate the neural system. Second, we foresee an increase in therapies combining different training principles, for example, the combination of NMES and robotics or neuromodulating drugs. Finally, with the ever-increasing pressure on healthcare budgets, it is expected that clinical and economic evidence will become more relevant in transferring these interventions to a wider community.

Disentangling the contribution of the paretic and non-paretic ankle to balance control in stroke patients.

During stroke recovery, restoration of the paretic ankle and compensation in the non-paretic ankle may contribute to improved balance maintenance. We examine a new approach to disentangle these recovery mechanisms by objectively quantifying the contribution of each ankle to balance maintenance. Eight chronic hemiparetic patients were included. Balance responses were elicited by continuous random platform movements. We measured body sway and ground reaction forces below each foot to calculate corrective ankle torques in each leg. These measurements yielded the Frequency Response Function (FRF) of the stabilizing mechanisms, which expresses the amount and timing of the generated corrective torque in response to sway at the specified frequencies. The FRFs were used to calculate the relative contribution of the paretic and non-paretic ankle to the total amount of generated corrective torque to correct sway. All patients showed a clear asymmetry in the balance contribution in favor of the non-paretic ankle. Paretic balance contribution was significantly smaller than the contribution of the paretic leg to weight bearing, and did not show a clear relation with the contribution to weight bearing. In contrast, a group of healthy subjects instructed to distribute their weight asymmetrically showed a one-on-one relation between the contribution to weight bearing and to balance. We conclude that the presented approach objectively quantifies the contribution of each ankle to balance maintenance. Application of this method in longitudinal surveys of balance rehabilitation makes it possible to disentangle the different recovery mechanisms. Such insights will be critical for the development and evaluation of rehabilitation strategies.

Percutaneous neuromuscular electrical stimulation (P-NMES) for treating shoulder pain in chronic hemiplegia. Effects on shoulder pain and quality of life.

OBJECTIVE: To evaluate the effect of percutaneous neuromuscular electrical stimulation (P-NMES) of the shoulder muscles on shoulder pain intensity and health-related quality of life in chronic hemiplegia. DESIGN: Prospective, open label design. SETTING: The outpatient services of a large teaching rehabilitation hospital in The Netherlands. SUBJECTS: Fifteen stroke survivors with chronic (> six months) hemiplegia and a therapy-resistant painful shoulder with subluxation. All patients suffered from clinically relevant shoulder pain, as assessed by a score of at least 4 out of 10 on a numerical rating scale. Shoulder subluxation was indicated by at least 1/2 fingerbreadth of glenohumeral separation on palpation. INTERVENTION: Six hours of P-NMES per day for a total of six weeks. MAIN OUTCOME MEASURES: Shoulder pain (Brief Pain Inventory), shoulder subluxation (clinical and radiographic), shoulder pain-free external rotation (hand-held goniometer), motor impairment (Fugl-Meyer Motor test) and quality of life (SF-36) were assessed before treatment, after six weeks of intramuscular stimulation, at three months and six months follow-up. RESULTS: A significant reduction in pain was found on the Brief Pain Inventory. Pain reduction was still present at six months follow-up. All domains, in particular bodily pain, of the SF-36 showed improvement in the short term. After six months of follow-up, bodily pain was still strongly and significantly reduced, whereas social functioning and role physical demonstrated a nonsignificant improvement of more than 10% compared with baseline. CONCLUSION: This pilot suggests that P-NMES potentially reduces shoulder pain in chronic hemiplegia. To establish the clinical value of P-NMES in treating hemiplegic shoulder pain a randomized controlled trial is needed.