Use of shoulder flexors to achieve isometric elbow extension in C6 tetraplegic patients during weight shift

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.

Upper limb electromyographic analysis of manual wheelchair transfer techniques in individuals with spinal cord injury: A systematic review

BACKGROUND AND PURPOSE

The objective of this study is to determine the upper limb muscle electromyographic (EMG) activity required during various manual wheelchair transfers in the population of spinal cord injury (SCI).

METHODS

This review included observational studies reporting the (EMG) activity of upper limb muscles during wheelchair transfers in people with SCI. We searched electronic databases and reference lists of relevant literature between 1995 and March 2022 with English language limits, yielding 3870 total articles. Two independent researchers performed data extraction and conducted quality assessment using two checklists, the Modified Downs and Blacks and National Heart, Lung, and Blood Institute for observational cohort and cross-sectional studies.

RESULTS

After eligibility screening, seven studies were included in this review. The sample size ranged from 10 to 32 participants aged 31-47 years. They assessed four types of transfers and mostly evaluated six upper limb muscles were biceps, triceps, anterior deltoid, pectoralis major, latissimus dorsi and ascending fibres of the trapezius. The peak EMG value indicated that muscle recruitment varied in both upper limbs according to the task demand, and the highest activity was seen during the lift-pivot transfer phase. Because of the data heterogeneity, a meta-analysis of study results was not feasible.

CONCLUSION

There were various ways of reporting the upper limb EMG muscle activity profile across all the included studies with a limited sample size. The crucial role of upper limb muscles during different types of manual wheelchair transfers was interpreted in this review. This is essential for predicting functional independence of individuals with SCI and warranting optimal rehabilitation strategies for wheelchair transfer skills.

Effect of biceps-to-triceps transfer on rotator cuff stress during upper limb weight-bearing lift in tetraplegia: A modeling and simulation analysis

Rotator cuff stress during upper limb weight-bearing lifts presumably contribute to rotator cuff disease, which is the most common cause of shoulder pain in individuals with tetraplegia. Elbow extension strength appears to be a key determinant of rotator cuff stress during upper limb weight-bearing lifts since individuals with paraplegia who generate greater elbow extensor moments experience lower rotator cuff stress relative to individuals with tetraplegia. Biceps-to-triceps transfer surgery can increase elbow extension strength in individuals with tetraplegia. The purpose of this study was to determine whether active elbow extension via biceps transfer decreases rotator cuff stress during weight-bearing lifts in individuals with tetraplegia. A forward dynamics computational framework was used to estimate muscle stress during the lift; stress was computed as muscle force divided by the peak isometric muscle force. We hypothesized that rotator cuff stresses would be lower in simulated lifting with biceps transfer relative to simulated lifting without biceps transfer. We found that limited elbow extension strength in individuals with tetraplegia, regardless of whether elbow strength is enabled via biceps transfer or is residual after spinal cord injury, results in muscle stresses exceeding 85% of the peak isometric muscle stress in the supraspinatus, infraspinatus, and teres minor. The rotator cuff stresses we estimated suggest that performance of weight-bearing activities should be minimized or assisted in order to reduce the risk for shoulder pain. Our results also indicate that biceps transfer is unlikely to decrease rotator cuff stress during weight-bearing lifts in individuals with tetraplegia.

Monitoring Upper Limb Recovery after Cervical Spinal Cord Injury: Insights beyond Assessment Scores

BACKGROUND

Preclinical investigations in animal models demonstrate that enhanced upper limb (UL) activity during rehabilitation promotes motor recovery following spinal cord injury (SCI). Despite this, following SCI in humans, no commonly applied training protocols exist, and therefore, activity-based rehabilitative therapies (ABRT) vary in frequency, duration, and intensity. Quantification of UL recovery is limited to subjective questionnaires or scattered measures of muscle function and movement tasks.

OBJECTIVE

To objectively measure changes in UL activity during acute SCI rehabilitation and to assess the value of wearable sensors as novel measurement tools that are complimentary to standard clinical assessments tools.

METHODS

The overall amount of UL activity and kinematics of wheeling were measured longitudinally with wearable sensors in 12 thoracic and 19 cervical acute SCI patients (complete and incomplete). The measurements were performed for up to seven consecutive days, and simultaneously, SCI-specific assessments were made during rehabilitation sessions 1, 3, and 6 months after injury. Changes in UL activity and function over time were analyzed using linear mixed models.

RESULTS

During acute rehabilitation, the overall amount of UL activity and the active distance wheeled significantly increased in tetraplegic patients, but remained constant in paraplegic patients. The same tendency was shown in clinical scores with the exception of those for independence, which showed improvements at the beginning of the rehabilitation period, even in paraplegic subjects. In the later stages of acute rehabilitation, the quantity of UL activity in tetraplegic individuals matched that of their paraplegic counterparts, despite their greater motor impairments. Both subject groups showed higher UL activity during therapy time compared to the time outside of therapy time.

CONCLUSION

Tracking day-to-day UL activity is necessary to gain insights into the real impact of a patient's impairments on their UL movements during therapy and during their leisure time. In the future, this novel methodology may be used to reliably control and adjust ABRT and to evaluate the progress of UL rehabilitation in clinical trials.

Trunk and upper extremity kinematics during sitting pivot transfers performed by individuals with spinal cord injury

BACKGROUND

Although reaching an optimal level of independence during sitting pivot transfer is crucial for individuals with spinal cord injury, little is known regarding the kinematic requirements of this functional task.

METHODS

Ten males with spinal cord injury performed independent sitting pivot transfers between an initial seat and a target one placed at same (50 cm), lower (40 cm), and higher heights (60 cm) than the initial one, using their usual movement strategies. Three-dimensional trunk, shoulder, elbow and wrist kinematics were collected bilaterally during sitting pivot transfers. Each sitting pivot transfer was divided into three phases for analysis: pre-lift, lift-pivot and post-lift. Temporal parameters were also documented.

FINDINGS

Peak shoulder extension displacement and velocities were always higher at the leading shoulder compared to the trailing one (P<0.004), and almost coincided with peak trunk velocities early during the lift phase. With increasing target seat height, shoulder flexion (P<0.011) and elbow extension (P<0.013) displacements and velocities of the trailing upper extremity augmented and reached higher values at this upper extremity compared to the leading upper extremity, with one exception at the shoulder. Elbows generally remained flexed (min=28-56 degrees ) during the lift phase of all transfers whereas extreme wrist extension positions (max=84-88 degrees ) were documented across all transfers. Total durations of transfers (2.6-2.8s) and lift-pivot phases (1.0-1.3s) were not affected by target seat heights.

INTERPRETATION

Sitting pivot transfers are characterized by substantial angular displacements and velocities at the trunk and upper extremities. Some kinematic parameters documented during sitting pivot transfers may increase the risk of developing secondary musculoskeletal impairments in this population.

Triceps denervation as a predictor of elbow flexion contractures in C5 and C6 tetraplegia

OBJECTIVE

To determine whether the existence of elbow flexion contractures in persons with C5 or C6 tetraplegia is related to a lack of residual voluntary triceps function and triceps denervation (ie, lower motoneuron damage).

DESIGN

A retrospective study of impairment data from 74 arms to identify the incidence of elbow flexion contractures and the contributing factors toward this deformity.

SETTING

Five spinal cord injury (SCI) rehabilitation centers in the United States, 1 in England, and 1 in Australia.

PARTICIPANTS

Forty-three subjects with motor complete C5 or C6 traumatic SCI.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Active and passive elbow extension, triceps voluntary muscle strength, and triceps response to electric stimulation.

RESULTS

Subjects with weak voluntary triceps had significantly fewer and less severe elbow flexion contractures than those with paralyzed triceps ( P =.024). Subjects with completely denervated triceps (ie, no response to electric stimulation) had significantly more elbow flexion contractures than subjects with even a weak response to electric stimulation ( P =.003). Overall, 51% of the arms could not be passively extended to zero. Forty-six percent of the arms classified as C5 lacked full passive elbow extension, compared with 63% of the arms classified as C6 ( P =.302).

CONCLUSIONS

A relationship has been found between elbow flexion contractures and lack of residual voluntary triceps and triceps denervation in subjects with C5 or C6 tetraplegia. There should be a greater awareness of the elbow flexion contractures that may develop as a result of this relationship. A better understanding of this deformity and its characteristics can lead to more effective clinical treatment and prevention strategies.

Movement patterns and muscular demands during posterior transfers toward an elevated surface in individuals with spinal cord injury

STUDY DESIGN

Three-dimensional kinematic analysis and surface electromyography (EMG) of 10 male adults with complete spinal cord injury (C7 to L2).

OBJECTIVE

To examine movement patterns and muscular demands in individuals with spinal cord injury (SCI) during posterior transfers.

SETTING

Pathokinesiology Laboratory at a Rehabilitation Centre, Montreal, Canada.

METHODS

Kinematic variables that described the positions and angular displacements of the head, trunk, shoulder and elbow were obtained by videotaping markers placed on the subject segments. EMG data were recorded for the biceps, triceps, anterior deltoid, pectoralis major, latissimus dorsi and trapezius muscles of the dominant upper extremity during posterior transfers using surface electrodes. To quantify the muscular demand, the EMG data recorded during the transfers were normalized to values obtained during maximal static contractions (EMGmax). The mean muscular demand was calculated for every muscle during the lift phase of the transfers. The lift phase was determined by pressure-sensitive contacts.

RESULTS

All subjects were able to execute the posterior transfers on an even surface, whereas nine subjects completed at least one of the transfers to the elevated surface. A forward-flexion pattern at the head and trunk was observed when either one or two hands remained on the lower surface, whereas a lift strategy was seen when both hands were placed on the elevated surface. Transferring to the elevated surface with hands on the lower surface required inferior electromyographic muscular utilization ratio (EMUR) than the transfer on the even surface for all muscles. The lowest EMUR were calculated for the transfer to the elevated surface with hands on the lower surface (triceps (18%), pectoralis major (53.8%), trapezius (66%) and latissimus dorsi (24.5%)) while performing the same transfer with hands on the elevated surface generated the highest EMUR (triceps (40.2%), anterior deltoid (73.2%), trapezius (83.6%) and latissimus dorsi (55.3%)).

CONCLUSIONS

Subjects presented different movement characteristics and muscular demands during the posterior transfers. It is suggested that the forward-flexion pattern improves the dynamic trunk stability and reduces the muscular demand required to transfer. High muscular demand developed when hands were positioned on the elevated surface might be due to increased postural control demands on the upper limb and reduced angular momentum.

Biomechanical analysis of a posterior transfer maneuver on a level surface in individuals with high and low-level spinal cord injuries

OBJECTIVE

The purpose of this study was to determine the movement patterns and the muscular demand during a posterior transfer maneuver on a level surface in individuals with spinal cord injuries.

DESIGN

Six participants with high-level spinal cord injury (C7 to T6) were compared to five participants with low-level spinal cord injury (T11 to L2) with partial or complete control of abdominal musculature.

BACKGROUND

Developing an optimal level of independence for transfer activities figures among the rehabilitation goals of individuals with spinal cord injury. There has been no biomechanical study which specifically describes the posterior transfer maneuver.

METHODS

Tridimensional kinematics at the elbow, shoulder, head and trunk, as well as surface electromyographic data of the biceps, triceps, anterior deltoid, posterior deltoid, pectoralis major, latissimus dorsi, trapezius and rectus abdominus muscles were recorded during the posterior transfer. To quantify the muscular demand, the electromyographic data were amplitude normalized to the peak value obtained from maximum voluntary contractions. The transfer was divided into pre-lift, lift, and post-lift phases for analysis.

RESULTS

The duration of the lift phase was significantly shorter (P<0.05) for the high-level spinal cord injury (1.24; SD, 0.37 s) when compared to the low-level spinal cord injury (1.74; SD, 0.39 s). The patterns and magnitudes of the angular displacements were found similar between groups (P values: 0.45-0.98). However, the high-level spinal cord injury initiated the task from a forward flexed posture, whereas the low-level spinal cord injury adopted an almost upright alignment of the trunk. Higher muscular demands were calculated for all muscles among high-level spinal cord injury participants during the transfer when compared to the low-level spinal cord injury. However, only the anterior deltoid (high level=92.4%; low level=34.2%) and the pectoralis major (high level=109.8%; low level=25.6%) reached statistical significance during the lift phase.Conclusions. Participants with high-level spinal cord injury presented different movement characteristics and higher muscular demands during the posterior transfer than low-level spinal cord injury ones. This is probably to compensate for the additional trunk and upper limb musculature impairment.

RELEVANCE

The findings of this study may help to develop guidelines of specific strengthening programs for the thoracohumeral, scapulothoracic and shoulder muscles designed to restore optimal transfer capacity in individuals with spinal cord injury. Furthermore, innovative rehabilitation programs targeting the ability to control the trunk could be beneficial for these individuals.

Effect of elbow flexion contractures on the ability of people with C5 and C6 tetraplegia to lift

BACKGROUND AND PURPOSE

It is commonly assumed that minor elbow flexion contractures prevent people with C5-C6 tetraplegia and paralysis of the triceps brachii muscles from bearing full body weight through their upper limbs. The aim of the present study was to determine the effect of simulated bilateral elbow flexion contractures on the ability of these individuals to bear weight through their upper limbs and to determine whether full passive elbow extension is truly critical for lifting body weight.

METHOD

A biomechanical study was performed. Body weight lifted was measured under conditions that simulated bilateral elbow flexion contractures. Five people with motor complete C6 tetraplegia and one person with motor complete C5 tetraplegia, all with bilateral paralysis of the triceps brachii muscles, were recruited to the study. Subjects were fitted with bilateral elbow splints that restricted elbow extension but did not restrain elbow flexion nor prevent the elbow from collapsing, and were seated on an instrumented platform that measured vertical forces under the buttocks. Subjects pushed down through their hands and lifted under five different conditions, namely: with no elbow splints; with bilateral elbow splints adjusted to restrict elbow extension by 5-10 degrees; by 15-20 degrees; by 25-30 degrees and with bilateral elbow splints adjusted to allow unrestricted movement of the elbow joint. Maximal weight lifted from under the buttocks, for each condition, was expressed in relation to weight under the buttocks during unsupported sitting (that is, 'seated body weight').

RESULTS

Subjects lifted progressively less weight from under their buttocks as passive elbow restriction was progressively restricted. However, one subject lifted all his seated body weight when elbow extension was restricted by 5-10 degrees and another lifted all his seated body weight when elbow extension was restricted by 5-10 degrees and 15-20 degrees.

CONCLUSIONS

Minor elbow flexion contractures will not alone prevent people with tetraplegia and paralysis of the triceps brachii muscles from lifting. Full passive elbow extension is not critical for the performance of this task.

Electrical stimulation: can it increase muscle strength and reverse osteopenia in spinal cord injured individuals?

OBJECTIVE

To study the extent to which atrophy of muscle and progressive weakening of the long bones after spinal cord injury (SCI) can be reversed by functional electrical stimulation (FES) and resistance training.

DESIGN

A within-subject, contralateral limb, and matching design.

SETTING

Research laboratories in university settings.

PARTICIPANTS

Fourteen patients with SCI (C5 to T5) and 14 control subjects volunteered for this study.

INTERVENTIONS

The left quadriceps were stimulated to contract against an isokinetic load (resisted) while the right quadriceps contracted against gravity (unresisted) for 1 hour a day, 5 days a week, for 24 weeks.

MAIN OUTCOME MEASURES

Bone mineral density (BMD) of the distal femur, proximal tibia, and mid-tibia obtained by dual energy x-ray absorptiometry, and torque (strength).

RESULTS

Initially, the BMD of SCI subjects was lower than that of controls. After training, the distal femur and proximal tibia had recovered nearly 30% of the bone lost, compared with the controls. There was no difference in the mid-tibia or between the sides at any level. There was a large strength gain, with the rate of increase being substantially greater on the resisted side.

CONCLUSION

Osteopenia of the distal femur and proximal tibia and the loss of strength of the quadriceps can be partly reversed by regular FES-assisted training.

Biomechanical analysis of a weight-relief maneuver in C5 and C6 quadriplegia

OBJECTIVE

To determine the kinematics and kinetics of performing a weight-relief maneuver in persons with C5 and C6 quadriplegia.

STUDY DESIGN

A three-dimensional kinematic and kinetic analysis was performed on the upward phase of a weight-relief maneuver with the use of a motion analysis system, two force platforms, and an instrumented seat. Electromyography (EMG) data were collected from the upper pectoralis, anterior deltoid, latissimus dorsi, and biceps brachii muscles of the right upper limb.

SETTING

Biomechanics laboratory.

SUBJECTS

Seven persons with C5 and C6 quadriplegia (ASIA A and B) with "flickers" (grade 1/5) or less in wrist flexor and triceps brachii muscles.

MAIN OUTCOME MEASURES

Angular displacements and associated moments of the shoulder, elbow, and wrist, kinematic variables describing the position and displacement of the trunk and upper limbs, and EMG data.

RESULTS

Subjects lifted from a forward flexed posture with their arms adducted against their trunks. During the course of lifting, they flexed their shoulders and wrists and extended their elbows. They generated peak mean (+/- SE) shoulder and elbow flexor moments of .65 (+/-.04) and .41 (+/-.06) N x m x kg(-1), respectively. Shoulder adductor moments increased over the course of the lift. The median (and interquartile range) mean EMG activity in the upper pectoralis and the anterior deltoid muscles were 63% (35%-76%) and 44% (36%-49%) of EMG obtained during maximal voluntary contractions, respectively.

CONCLUSION

Persons with quadriplegia with paralysis of the triceps brachii muscles lift themselves by generating active shoulder flexor and adductor moments. They also rely on wrist flexor moments that are generated by the stretch of the wrist flexor muscles.

Electrically stimulated elbow extension in persons with C5/C6 tetraplegia: a functional and physiological evaluation

OBJECTIVE

To measure the effect of electrically stimulated triceps on elbow extension strength, range of motion, and the performance of overhead reaching tasks.

SETTING

Clinical research laboratory.

PARTICIPANTS

Four individuals with spinal cord injuries at the C5 or C6 motor level.

INTERVENTIONS

The participants, who already had an implanted upper extremity neuroprosthesis, were provided with elbow extension through functional electrical stimulation (FES) of the triceps brachii.

MAIN OUTCOME MEASURES

Comparisons of stimulated elbow extension to voluntary elbow extension: (1) evaluations of impairment such as range of motion and strength; (2) performance of a set of functional overhead reaching tasks that required elbow extension; (3) a usage survey (conducted by telephone) to examine use of triceps stimulation in the home and community.

RESULTS

All participants achieved greater range of motion and strength of elbow extension with stimulated triceps versus without. Overall functional task performance improved in 100% of the tasks tested for all but one participant, who showed improvement in 60% of the tasks. Participants reported using the triceps in at least one activity for at least 90% of the days the neuroprosthesis was donned.