Implicit and explicit motor imagery ability after SCI: Moving the elbow makes the difference.

Cervical spinal cord injury (SCI) causes dramatic sensorimotor deficits that restrict both activity and participation. Restoring activity and participation requires extensive upper limb rehabilitation focusing elbow and wrist movements, which can include motor imagery. Yet, it remains unclear whether MI ability is impaired or spared after SCI. We investigated implicit and explicit MI ability in individuals with C6 or C7 SCI (SCIC6 and SCIC7 groups), as well as in age- and gender-matched controls without SCI. Inspired by previous studies, implicit MI evaluations involved hand laterality judgments, hand orientation judgments (HOJT) and hand-object interaction judgments. Explicit MI evaluations involved mental chronometry assessments of physically possible or impossible movements due to the paralysis of upper limb muscles in both groups of participants with SCI. HOJT was the paradigm in which implicit MI ability profiles differed the most between groups, particularly in the SCIC6 group who had impaired elbow movements in the horizontal plane. MI ability profiles were similar between groups for explicit MI evaluations, but reflected task familiarity with higher durations in the case of unfamiliar movements in controls or attempt to perform movements which were no longer possible in persons with SCI. Present results, obtained from a homogeneous population of individuals with SCI, suggest that people with long-term SCI rely on embodied cognitive motor strategies, similar to controls. Differences found in behavioral response pattern during implicit MI mirrored the actual motor deficit, particularly during tasks that involved internal representations of affected body parts.

Impaired tongue motor control after temporomandibular disorder: A proof-of-concept case-control study of tongue print.

BACKGROUND: Temporomandibular disorder (TMD) perturbs the tongue motor control and consequently impairs oral function, but strength training reduces this impairment. However, tongue motor control is widely reduced to a matter of strength. OBJECTIVES: To investigate the accuracy of the tongue placement as a measure of tongue motor control in patients with TMD compared with age- and sex-matched healthy participants. MATERIAL AND METHODS: This proof-of-concept case-control study was prospective, observational, and part of the TMIQ study (NCT04102306). After pointing against a wood stick while maintaining the tongue as sharp as possible, the examinator drew the contour of the tongue print on the wood stick, which was then scanned for image analyses to compute the area for each participant using ImageJ. RESULTS: A total of 94 participants were included, all patients with TMD (n = 47) diagnosed with myalgia, 61% with intra-articular joint disorder accordingly to the DC/TMD. The median (IQR) tongue print area was 117 (111) mm2 for the TMD group and 93.5 (76.2) mm2 for the control group (V = 352, p = .04) and the median [95% confidence interval] difference was 25.4 [1.3; 51.0] mm². Overlapping of the 95% confidence intervals of the area evidenced no significant difference between the categories of the DC/TMD. The corrected each area-total correlation (r = .24) suggests a reasonably homogenous thus valid measure. CONCLUSION: The results suggest that TMD impairs the motor control of the tongue. Therefore, the sharpest tongue pointing test may constitute a simple and accessible clinical tool to assess the accuracy of tongue placement in TMD patients. The study was registered on ClinicalTrial.gov with identification number NCT04102306.

Tongue and mouth imagery questionnaire (TMIQ) for assessing motor imagery vividness of the temporomandibular region: A reliability and validity case-control study.

BACKGROUND: To date, no validated assessment of motor imagery (MI) ability with temporomandibular disorders (TMD) exists preventing identification of good imagers and appropriate MI use during TMD rehabilitation. OBJECTIVE: To assess the reliability and construct validity of the previously developed Tongue and Mouth Imagery Questionnaire (TMIQ) compared with the gold-standard Kinaesthetic and Visual Imagery Questionnaire (KVIQ-10). METHODS: Both KVIQ-10 and TMIQ assess MI ability using vividness (i.e. clarity/brightness for visual MI, V MI; or intensity for kinesthetic MI, K MI) of MI using a 5-point Likert scale (1: no image/sensation, 5: clear/intense image/sensation). The KVIQ-10 was administered once (test) and the TMIQ twice (test-retest) to heathy participants and patients with TMD. Questionnaire validity was investigated using concurrent validity (Pearson correlation and paired t test); TMIQ-test-retest reliability (intraclass correlation coefficients, ICCs); internal consistency (Cronbach ⍺) and the factorial structure (principal factor extraction). RESULTS: A total of 94 participants were included (n = 47 per group). The mean vividness scores of the KVIQ-10 and the TMIQ were significantly correlated, and not significantly different for both groups indicating concurrent validity. ICCs in the control group (range: 0.82-0.90), and in the TMD group (range: 0.75-0.82) indicated good reproducibility. The Cronbach ⍺ values were all above 0.94, indicating excellent reliability. Two factors were extracted corresponding to V MI and K MI, and explained 66% of total variance. CONCLUSION: The TMIQ is a valid and reproducible MI questionnaire showing excellent internal consistency and, therefore, can be used to assess imagined movements of the TM region in healthy individuals and patients with TMD.

Slacklining as therapy to address non-specific low back pain in the presence of multifidus arthrogenic muscle inhibition.

Low back pain (LBP) represents the most prevalent, problematic and painful of musculoskeletal conditions that affects both the individual and society with health and economic concerns. LBP is a heterogeneous condition with multiple diagnoses and causes. In the absence of consensus definitions, partly because of terminology inconsistency, it is further referred to as non-specific LBP (NSLBP). In NSLBP patients, the lumbar multifidus (MF), a key stabilizing muscle, has a depleted role due to recognized myocellular lipid infiltration and wasting, with the potential primary cause hypothesized as arthrogenic muscle inhibition (AMI). This link between AMI and NSLBP continues to gain increasing recognition. To date there is no 'gold standard' or consensus treatment to alleviate symptoms and disability due to NSLBP, though the advocated interventions are numerous, with marked variations in costs and levels of supportive evidence. However, there is consensus that NSLBP management be cost-effective, self-administered, educational, exercise-based, and use multi-modal and multi-disciplinary approaches. An adjuvant therapy fulfilling these consensus criteria is 'slacklining', within an overall rehabilitation program. Slacklining, the neuromechanical action of balance retention on a tightened band, induces strategic indirect-involuntary therapeutic muscle activation exercise incorporating spinal motor control. Though several models have been proposed, understanding slacklining's neuro-motor mechanism of action remains incomplete. Slacklining has demonstrated clinical effects to overcome AMI in peripheral joints, particularly the knee, and is reported in clinical case-studies as showing promising results in reducing NSLBP related to MF deficiency induced through AMI (MF-AMI). Therefore, this paper aims to: rationalize why and how adjuvant, slacklining therapeutic exercise may positively affect patients with NSLBP, due to MF-AMI induced depletion of spinal stabilization; considers current understandings and interventions for NSLBP, including the contributing role of MF-AMI; and details the reasons why slacklining could be considered as a potential adjuvant intervention for NSLBP through its indirect-involuntary action. This action is hypothesized to occur through an over-ride or inhibition of central down-regulatory induced muscle insufficiency, present due to AMI. This subsequently allows neuroplasticity, normal neuro-motor sequencing and muscle re-activation, which facilitates innate advantageous spinal stabilization. This in-turn addresses and reduces NSLBP, its concurrent symptoms and functional disability. This process is hypothesized to occur through four neuro-physiological processing pathways: finite neural delay; movement-control phenotypes; inhibition of action and the innate primordial imperative; and accentuated corticospinal drive. Further research is recommended to investigate these hypotheses and the effect of slacklining as an adjuvant therapy in cohort and control studies of NSLBP populations.

Inconclusive efficacy of intervention on upper-limb function after tetraplegia: A systematic review and meta-analysis.

BACKGROUND: Rehabilitation aims to improve hand-arm function, upper-limb strength, and functional independence that has been impaired by tetraplegia. On the basis of evidence derived from stroke rehabilitation, interventions aiming to increase intensity (i.e., duration and/or number of movements practiced) or alter brain plasticity (including motor imagery, virtual reality, transcranial direct-current or magnetic stimulations; i.e., neuromodulation) are now used during tetraplegic rehabilitation. However, no meta-analysis has investigated the efficacy of these interventions. OBJECTIVE: This systematic review and meta-analysis investigated, separately, the efficacy of these interventions to alter hand-arm function, upper-limb strength, and functional independence of individuals with tetraplegia. METHODS: Two independent reviewers followed the PROSPERO protocol (CRD42018098506) for this systematic review. MEDLINE, PEDro CENTRAL, and SCOPUS databases were searched for reports of randomized controlled trials of individuals with tetraplegia that were published in English. We performed a meta-analysis of intensive versus less intensive interventions and neuromodulation versus sham interventions considering hand-arm function, strength, and functional independence. RESULTS: From 168 records identified, we included 29 studies (all but 1 were single-centre) in the systematic review (647 participants with C2 to T1 tetraplegia [American Spinal Injury Association impairment scale A to D]). Interventions lasted from 66 to 40,320min. Five studies were retained in the intensity meta-analyses and 5 in the neuromodulation meta-analyses. Overall, 3/5 and 1/5 studies had adequate methodology (Cochrane Risk of Bias score ≥6/10). For each outcome, the p-values for the overall effect were>0.05. Heterogeneity was low, but when analyzing intensity, it was moderate for functional independence and high for hand-arm function. Quality of evidence was very low to low. CONCLUSIONS: We can provide no recommendations for using intensive versus less intensive interventions or neuromodulation versus sham during tetraplegia rehabilitation. Further multicentre studies of high methodological quality are required to reduce uncertainty about the efficacy of these interventions.

Descriptive pilot study of vividness and temporal equivalence during motor imagery training after quadriplegia.

BACKGROUND: Motor imagery (MI) training is often used to improve physical practice (PP), and the functional equivalence between imagined and practiced movements is widely considered essential for positive training outcomes. OBJECTIVE: We previously showed that a 5-week MI training program improved tenodesis grasp in individuals with C6-C7 quadriplegia. Here we investigated whether functional equivalence changed during the course of this training program. METHODS: In this descriptive pilot study, we retrospectively analyzed data for 6 individuals with C6-C7 quadriplegia (spinal cord injured [SCI]) and 6 healthy age-matched controls who trained for 5 weeks in visual and kinesthetic motor imagery or visualization of geometric shapes (controls). Before training, we assessed MI ability by using the Kinesthetic and Visual Imagery Questionnaire (KVIQ). We analyzed functional equivalence by vividness measured on a visual analog scale (0-100) and MI/PP time ratios computed from imagined and physically practiced movement durations measured during MI training. These analyses were re-run considering that half of the participants with quadriplegia were good imagers and the other half were poor imagers based on KVIQ scores. To investigate generalization of training effects, we analyzed MI/PP ratios for an untrained pointing task before (3 baseline measures), immediately after, and 2 months after training. RESULTS: During MI training, imagery vividness increased significantly. Only the good imagers evolved toward temporal equivalence during training. Good imagers were also the only participants who showed changes in temporal equivalence on the untrained pointing task. CONCLUSION: This is the first study reporting improvement in functional equivalence during an MI training program that improved tenodesis grasp in individuals with C6-C7 quadriplegia. We recommend that clinical MI programs focus primarily on vividness and suggest that feedback about movement duration could potentially improve temporal equivalence, which could in turn lead to further improvement in PP.

Functional electrical stimulation cycling strategies tested during preparation for the First Cybathlon Competition - a practical report from team ENS de Lyon.

Whether it is from the patient's or the physical therapist's point of view, FES cycling can be considered either as a recreational activity, or an engaging rehabilitation tool. In both cases, it keeps patients with lower-limb paralysis motivated to sustain a regular physical activity. Thus, it is not surprising that it was selected as one of the six disciplines of the first Cybathlon competition held on October 8, 2016. However, many unresolved issues prevent FES cycling from being an activity practiced outdoors on a daily basis; such as, low power production, rapid muscle fatigue, precise electrode positioning, lack of systematic procedures to determine stimulation patterns, and the difficulty of transferring disabled riders from their wheelchair to the tricycle. This article documents the challenges we faced during preparation for the Cybathlon 2016 FES cycling race, and provides results obtained during different phases of the process. A particular specificity of our team was that, unlike most other teams where pilots were mainly paraplegic, both the primary and backup pilots for team ENS de Lyon are C6/C7 tetraplegics, with neither voluntary control of their abdominal muscles nor hand grip, and only partial use of their arms.

Motor imagery reinforces brain compensation of reach-to-grasp movement after cervical spinal cord injury.

Individuals with cervical spinal cord injury (SCI) that causes tetraplegia are challenged with dramatic sensorimotor deficits. However, certain rehabilitation techniques may significantly enhance their autonomy by restoring reach-to-grasp movements. Among others, evidence of motor imagery (MI) benefits for neurological rehabilitation of upper limb movements is growing. This literature review addresses MI effectiveness during reach-to-grasp rehabilitation after tetraplegia. Among articles from MEDLINE published between 1966 and 2015, we selected ten studies including 34 participants with C4 to C7 tetraplegia and 22 healthy controls published during the last 15 years. We found that MI of possible non-paralyzed movements improved reach-to-grasp performance by: (i) increasing both tenodesis grasp capabilities and muscle strength; (ii) decreasing movement time (MT), and trajectory variability; and (iii) reducing the abnormally increased brain activity. MI can also strengthen motor commands by potentiating recruitment and synchronization of motoneurons, which leads to improved recovery. These improvements reflect brain adaptations induced by MI. Furthermore, MI can be used to control brain-computer interfaces (BCI) that successfully restore grasp capabilities. These results highlight the growing interest for MI and its potential to recover functional grasping in individuals with tetraplegia, and motivate the need for further studies to substantiate it.

Improvement of grasping after motor imagery in C6-C7 tetraplegia: A kinematic and MEG pilot study.

PURPOSE: Grasp recovery after C6-C7-spinal cord injury (SCI) requires learning "tenodesis grasp" whereby active wrist extension elicits passive thumb-to-forefinger and finger-to-palm flexion. Evidence that motor imagery (MI) promotes upper limb function after tetraplegia is growing, but whether MI potentiates grasp recovery in C6-C7-SCI individuals who have successfully learned the "tenodesis grasp" remains unknown. METHODS: Six chronic stable C6-C7-SCI inpatients and six healthy control participants were included. C6-C7-SCI participants imagined grasping movements and controls visualized geometric forms for 45 minutes, three times a week for five weeks. Three separate measures taken over a five week period before the intervention formed the baseline. Intervention effects were assessed immediately after the intervention and eight weeks later. Each testing session consisted of kinematic recordings during reach-to-grasp and magnetoencephalographic (MEG) recordings during wrist extension. RESULTS: During baseline, kinematic wrist extension angle during "tenodesis grasp" and MEG contralateral sensorimotor cortex (cSMC) activity during wrist extension were stable. Moreover, SCI participants exhibited a greater number of voxels within cSMC than controls. After MI sessions, wrist extension angle increased during "tenodesis grasp" and the number of voxels within cSMC during wrist extension decreased and became similar to controls. CONCLUSION: These findings provide further support for the use of MI to reinforce a compensatory grasping movement (tenodesis) and induce brain plasticity.

Upper limb kinematics after cervical spinal cord injury: a review.

Although a number of upper limb kinematic studies have been conducted, no review actually addresses the key-features of open-chain upper limb movements after cervical spinal cord injury (SCI). The aim of this literature review is to provide a clear understanding of motor control and kinematic changes during open-chain upper limb reaching, reach-to-grasp, overhead movements, and fast elbow flexion movements after tetraplegia. Using data from MEDLINE between 1966 and December 2014, we examined temporal and spatial kinematic measures and when available electromyographic recordings. We included fifteen control case and three series case studies with a total of 164 SCI participants and 131 healthy control participants. SCI participants efficiently performed a broad range of tasks with their upper limb and movements were planned and executed with strong kinematic invariants like movement endpoint accuracy and minimal cost. Our review revealed that elbow extension without triceps brachii relies on increased scapulothoracic and glenohumeral movements providing a dynamic coupling between shoulder and elbow. Furthermore, contrary to normal grasping patterns where grasping is prepared during the transport phase, reaching and grasping are performed successively after SCI. The prolonged transport phase ensures correct hand placement while the grasping relies on wrist extension eliciting either whole hand or lateral grip. One of the main kinematic characteristics observed after tetraplegia is motor slowing attested by increased movement time. This could be caused by (i) decreased strength, (ii) triceps brachii paralysis which disrupts normal agonist-antagonist co-contractions, (iii) accuracy preservation at movement endpoint, and/or (iv) grasping relying on tenodesis. Another feature is a reduction of maximal superior reaching during overhead movements which could be caused by i) strength deficit in agonist muscles like pectoralis major, ii) strength deficit in proximal synergic muscles responsible for scapulothoracic and glenohumeral joint stability, iii) strength deficit in distal synergic muscles preventing the maintenance of elbow extension by shoulder elbow dynamic coupling, iv) shoulder joint ankyloses, and/or v) shoulder pain. Further studies on open chain movements are needed to identify the contribution of each of these factors in order to tailor upper limb rehabilitation programs for SCI individuals.

Neuroplasticity of imagined wrist actions after spinal cord injury: a pilot study.

Motor imagery (MI - i.e., the mental representation of an action without physically executing it) stimulates brain motor networks and promotes motor learning after spinal cord injury (SCI). An interesting issue is whether the brain networks controlling MI are being reorganized with reference to spared motor functions. In this pilot study, we tested using magnetoencephalography (MEG) whether changes in cortical recruitment during MI were related to the motor changes elicited by rehabilitation. Over a 1-year period of inclusion, C6 SCI participants (n = 4) met stringent criteria for inclusion in a rehabilitation program focused on the tenodesis prehension (i.e., a compensatory prehension enabling seizing of objects in spite of hand and forearm muscles paralysis). After an extended baseline period of 5 weeks including repeated MEG and chronometric assessments of motor performance, MI training was embedded to the classical course of physiotherapy for five additional weeks. Posttest MEG and motor performance data were collected. A group of matched healthy control participants underwent a similar procedure. The MI intervention resulted in changes in the variability of the wrist extensions, i.e., a key movement of the tenodesis grasp (p < .05). Interestingly, the extent of cortical recruitment, quantified by the number of MEG activation sources recorded within Brodmann areas 1-8 during MI of the wrist extension, significantly predicted actual movement variability changes across sessions (p < .001). However, no such relationship was present for movement times. Repeated measurements afforded a reliable statistical power (range .70-.97). This pilot study does not provide straightforward evidence of MI efficacy, which would require a randomized controlled trial. Nonetheless, the data showed that the relationship between action and imagery of spared actions may be preserved after SCI.