Measurement of motor-evoked potential resting threshold and amplitude of proximal and distal arm muscles in healthy adults. A reliability study

Purpose: Reliability of motor-evoked potential threshold and amplitude measurement of upper limb muscles is important when detecting changes in cortical excitability. The objective of this study was to investigate intra-rater, test-retest reliability and minimal detectable change of resting motor threshold and amplitude of a proximal and distal upper limb muscles, anterior deltoid and distal extensor digitorum communis in healthy adults. Method: To measure motor-evoked potential responses, transcranial magnetic stimulation was interfaced with electromyography and neuronavigation equipment. Two measurements were conducted on day 1 and a third measurement three days later. Reliability was analysed using intraclass correlation coefficients. Results: Twenty participants completed the study. Excellent intra-rater (intraclass correlation coefficient = 0.91 (extensor digitorum), 0.94 (anterior deltoid)) and good to excellent test-retest reliability (intraclass correlation coefficient = 0.69 (anterior deltoid), 0.84 (extensor digitorum)) was found for resting motor threshold. Minimal detectable change for resting motor threshold was found at 10.95% (extensor digitorum) and 16.35% (anterior deltoid) between first and third measurements. Motor-evoked potential amplitude of extensor digitorum communis had fair to good intra-rater (intraclass correlation coefficient = 0.50) and test-retest reliability (intraclass correlation coefficient = 0.65). Conclusions: Our results suggest that resting motor threshold is a reliable neurophysiological measure even for proximal shoulder muscles. Future research should further explore the reliability of motor-evoked potential amplitude before integration into neurological rehabilitation

A double-blinded randomised controlled trial exploring the effect of anodal transcranial direct current stimulation and uni-lateral robot therapy for the impaired upper limb in sub-acute and chronic stroke

BACKGROUND:Neurorehabilitation technologies such as robot therapy (RT) and transcranial Direct Current Stimulation (tDCS) can promote upper limb (UL) motor recovery after stroke. OBJECTIVE:To explore the effect of anodal tDCS with uni-lateral and three-dimensional RT for the impaired UL in people with sub-acute and chronic stroke. METHODS:A pilot randomised controlled trial was conducted. Stroke participants had 18 one-hour sessions of RT (Armeo®Spring) over eight weeks during which they received 20 minutes of either real tDCS or sham tDCS during each session. The primary outcome measure was the Fugl-Meyer assessment (FMA) for UL impairments and secondary were: UL function, activities and stroke impact collected at baseline, post-intervention and three-month follow-up. RESULTS:22 participants (12 sub-acute and 10 chronic) completed the trial. No significant difference was found in FMA between the real and sham tDCS groups at post-intervention and follow-up (p = 0.123). A significant ‘time’ x ‘stage of stroke’ was found for FMA (p = 0.016). A higher percentage improvement was noted in UL function, activities and stroke impact in people with sub-acute compared to chronic stroke. CONCLUSIONS:Adding tDCS did not result in an additional effect on UL impairment in stroke. RT may be of more benefit in the sub-acute than chronic phase

Is there a standard procedure for assessing and providing assistive devices for people with neuro-disabling conditions in United Kingdom? A nation-wide survey

Background: Assistive devices are currently provided to people with neuro-disabling conditions to promote or maintain independence in activities of daily living. However, it is unclear whether assessment procedures performed by health care professionals to guide the provision of assistive devices are standardized.  Objective: To explore the assessment and service-delivery processes of assistive devices for people with multiple sclerosis, cerebrovascular disease and Parkinson's disease experiencing physical disability by health care professionals in the United Kingdom.  Methods: A survey was conducted among UK health care professionals working with people with neuro-disabling conditions. Descriptive and content analyses were used to code survey data.  Results: In total, 231 health care professionals completed the survey: 93 occupational therapists, 136 physiotherapists and 2 assistant practitioners. Less than half of the respondents (46%) reported use of local, national, or combined guidelines when assessing a service user's suitability or need for assistive devices. When guidelines were used, they were not consistent and not specifically for assistive devices. The respondents stated that when users were allocated small and portable assistive devices, they were supplied within four weeks. This period increased for large equipment, major home adaptions or if external specialist services and/or funding was needed.  Conclusions: Standardized operating procedures for assistive device provision are not being carried out within the UK. Variable access to assistive devices supplied by the state indicates inequity across regions. Future research should explore potential benefits of developing standardized assessment procedures for the provision of assistive devices and devise methods to reduce current variability in service delivery

Using technology to optimize recovery in upper limb stroke rehabilitation

A skilled therapist working one-to-one with a patient for one or two hours a day may be an ideal environment to optimize recovery of upper limb function following stroke and is likely to be superior to technologies that ‘replace the therapist’. Repeated studies have found that there is no single therapeutic approach that is more effective than any other, but intensity is critical. The recent Randomized Controlled Trial of the MIT Manus, published by Lo et al, found that robot therapy was not superior to intensive conventional therapy. Given that one-to-one intensive therapy is unaffordable can technology be used to improve outcome and if so how? The key factors appear to be: increasing intensity of practice; motivating patients to maximize engagement, effort and compliance; performance of functional and relevant tasks; increasing Central Nervous System (CNS) excitability and early intervention. The evidence that technologies can be used to deliver on these key factors will be discussed and in particular the evidence and potential for combined therapies such as electrical stimulation (both peripheral and transcranial direct current stimulation [tDCS]) with robot therapy will be presented

Do people with multiple sclerosis perceive upper limb improvements from robotic-mediated therapy? A mixed methods study

BACKGROUND: Robot-mediated training is increasingly considered as a rehabilitation intervention targeting upper limb disability. However, experiences of such an intervention have been rarely explored in the multiple sclerosis population. This mixed methods study sought to explore the impact of an eight week upper limb robotic intervention on experiences of people with multiple sclerosis. METHODS: Eleven participants (Median EDSS- score: 6.5) with moderate to severe upper limb impairment, performed eight week robot- mediated training of the most affected arm. The training involved a virtual learning platform called I-TRAVLE with duration of 30 min per training session, twice to three times per week. Two subjective questionnaires with items from the Intrinsic Motivation Inventory (IMI) and Credibility and Expectancy Questionnaire (CEQ) were collected bi-weekly during the intervention. Approximately one month after completing the training, three focus groups were conducted. Main themes were identified using thematic analysis. RESULTS: Results from the IMI and CEQ indicated high patient satisfaction and expectation that the intervention will be beneficial for them. Two main themes were identified: (1) Effect of the intervention on impairment and activity in that participants felt that there was a positive impact of the training on strength, endurance and during activities of daily living and that it met their expectations; (2) Experiences based on system usage from the system in that participants expressed feelings of motivation and self-improvement. The participants also perceived the training as enjoyable and concluded that the use of games instigated a competitive spirit between the participants. CONCLUSIONS: Robot-mediated training could have a motivating effect and induce a general positive experience while reducing disabilities of people with multiple sclerosis

A qualitative study exploring views and experiences of people with stroke undergoing transcranial direct current stimulation and upper limb robot therapy

Background Neurorehabilitation technologies used mainly in research such as robot therapy (RT) and transcranial direct current stimulation (tDCS) can promote upper limb motor recovery after stroke. Understanding the feasibility and efficacy of stroke rehabilitation technologies for upper limb impairments is crucial for effective implementation in practice. Small studies have explored views of RT by people with stroke; however experiences of people receiving tDCS in combination with RT have never been explored. Objective To explore views and experiences of people with sub-acute and chronic stroke that had previously taken part in a randomised controlled trial involving tDCS and RT for their impaired upper limb. Methods An interview study includes open and closed questions. Face-to-face interviews were audio recorded. Open-ended question responses were transcribed and analyzed using thematic analysis; closed questions were analyzed using descriptive analysis. Results Participants felt that RT was enjoyable (90%) and beneficial for their affected arm (100%). From the open question data, it was found that the intervention was effective for the impaired arm especially in the sub-acute stage. Main reported concerns were that tDCS caused painful, itching and burning sensations and RT was sometimes tiring and difficult. Participants recommended that future research should focus on designing a more comfortable method of tDCS and develop a robot that promotes hand movements. Conclusions This study provides new knowledge about the benefits and barriers associated with these technologies which are crucial to the future effective implementation of these tools in practice

A systematic review investigating the relationship of electroencephalography and magnetoencephalography measurements with sensorimotor upper limb impairments after stroke

Background: Predicting sensorimotor upper limb outcome receives continued attention in stroke. Neurophysiological measures by electroencephalography (EEG) and magnetoencephalography (MEG) could increase the accuracy of predicting sensorimotor upper limb recovery.New method: The aim of this systematic review was to summarize the current evidence for EEG/MEG-based measures to index neural activity after stroke and the relationship between abnormal neural activity and sensorimotor upper limb impairment. Relevant papers from databases EMBASE, CINHAL, MEDLINE and pubMED were identified. Methodological quality of selected studies was assessed with the Modified Downs and Black form. Data collected was reported descriptively.Results: Seventeen papers were included; 13 used EEG and 4 used MEG applications. Findings showed that: (a) the presence of somatosensory evoked potentials in the acute stage are related to better outcome of upper limb motor impairment from 10 weeks to 6 months post-stroke; (b) an interhemispheric imbalance of cortical oscillatory signals associated with upper limb impairment; and (c) predictive models including beta oscillatory cortical signal factors with corticospinal integrity and clinical measures could enhance upper limb motor prognosis.Comparing with existing method: The combination of neurological biomarkers with clinical measures results in higher statistical power than using neurological biomarkers alone when predicting motor recovery in stroke.Conclusions: Alterations in neural activity by means of EEG and MEG are demonstrated from the early post-stroke stage onwards, and related to sensorimotor upper limb impairment. Future work exploring cortical oscillatory signals in the acute stage could provide further insight about prediction of upper limb sensorimotor recovery.peer-reviewe

A qualitative study exploring views and experiences of people with stroke undergoing transcranial direct current stimulation and upper limb robot therapy

BackgroundNeurorehabilitation technologies used mainly in research such as robot therapy (RT) and transcranial direct current stimulation (tDCS) can promote upper limb motor recovery after stroke. Understanding the feasibility and efficacy of stroke rehabilitation technologies for upper limb impairments is crucial for effective implementation in practice. Small studies have explored views of RT by people with stroke; however experiences of people receiving tDCS in combination with RT have never been explored.ObjectiveTo explore views and experiences of people with sub-acute and chronic stroke that had previously taken part in a randomised controlled trial involving tDCS and RT for their impaired upper limb.MethodsAn interview study includes open and closed questions. Face-to-face interviews were audio recorded. Open-ended question responses were transcribed and analyzed using thematic analysis; closed questions were analyzed using descriptive analysis.ResultsParticipants felt that RT was enjoyable (90%) and beneficial for their affected arm (100%). From the open question data, it was found that the intervention was effective for the impaired arm especially in the sub-acute stage. Main reported concerns were that tDCS caused painful, itching and burning sensations and RT was sometimes tiring and difficult. Participants recommended that future research should focus on designing a more comfortable method of tDCS and develop a robot that promotes hand movements.ConclusionsThis study provides new knowledge about the benefits and barriers associated with these technologies which are crucial to the future effective implementation of these tools in practice.</p

Reliability of motor evoked potential resting threshold and amplitude of proximal and distal arm muscles in healthy adults

Objectives: To quantify the intra-rater and test-retest reliability of the motor evoked potential (MEP) resting threshold (RT) and MEP amplitude of the anterior deltoid (AD) and extensor digitorum (ED) of healthy adults using Transcranial Magnetic Stimulation (TMS). Methods: Stimulation was performed on healthy adults with a Magstim® 2002 device using Brainsight® neuro-navigation. Surface EMG (Biometrics Ltd) was recorded from surface electrodes over AD and ED muscles. RT was defined as the minimal TMS intensity to recruit an MEP &gt; 50 ?V in five of ten consecutive measurements in both muscles. Measurements were made on three occasions in each participant by the same assessor. Two measurements were carried out on day one with 30 minutes rest in between (tests 1 and 2) and the third measurement was carried out three days later (test 3). Mean peak to peak amplitude of five MEPs at RT were analysed using MATLAB.Results: Twenty participants (10 males and 10 females, mean age of 59.86 years ±11.70SD) completed the study. There was good to excellent reliability of RT for ED and AD between tests 1 and 2 (ICC=0.89 and 0.94 respectively) and tests 1 and 3 (ICC=0.84 and 0.77 respectively). MEP amplitude between tests 1 and 2 had a poor to moderate level of agreement (ICC=0.42 [ED] and 0.53 [AD]) and between tests 1 and 3, moderate to very poor agreement was found (ICC=0.62 [ED] and 0.14 [AD]).Conclusions: RT and MEP amplitude are regularly used as neurophysiological outcome measures in neurorehabilitation research. Measurement of the RT showed excellent intra-rater and test-retest reliability in healthy adults. Measurement of MEP amplitude at RT of both muscles showed poor to moderate agreement. RT provides less information about changes in cortical excitability, however, our results suggest RT to be a more reliable neurophysiological measurement, which could be included in future neurorehabilitation trials