How do C6/C7 tetraplegic patients grasp balls of different sizes and weights? Impact of surgical musculo-tendinous transfers

[Upper limb motor and functional recovery in patients with tetraplegia]

OBJECTIVE

To study the recovery of the upper limb motor function and functional independence in patients with cervical spinal cord injury.

MATERIAL AND METHODS

The study included 49 patients with subacute tetraplegia, mean age 33±14.8 years, 42 men and 7 women, admitted to the Preodolenie Rehabilitation Center. The follow-up was up to 2 years. The clinical and functional states were assessed after 3, 6, 12 and more than 12 months after spinal injury, using the ASIA neurological standard scale, the motor subscale of Functional Independence Scale (FIM) and short form of Van Lieshout Test (VLT). All patients received continuous rehabilitation courses that included physiotherapy, occupational therapy, social support, psychological rehabilitation.

RESULTS

Upper limb motor recovery occurred in the first 6 months after spinal cord injury at 5±3.9 points (ASIA), while in 49% patients motor level decreased by one segment of the spinal cord, in 8% patients completeness of spinal cord injury improved. The improvement of functional independence was found during the first 12 months: according to FIM, in the period of 3-6 months by 18±11.1 points, in the period of 6-12 months by 8±8.1 points; according to VLT in the period of 3-6 months by 19±14.4 points, in the period of 6-12 months by 5.6±6.02 points.

CONCLUSIONS

Upper limb motor recovery mostly occurs in the first 6 months while the functional independence improvement lasts during the first 12 months after a spinal cord injury.

Phase-dependent deficits during reach-to-grasp after human spinal cord injury

Most cervical spinal cord injuries result in asymmetrical functional impairments in hand and arm function. However, the extent to which reach-to-grasp movements are affected in humans with incomplete cervical spinal cord injury (SCI) remains poorly understood. Using kinematics and electromyographic (EMG) recordings in hand and arm muscles we studied the different phases of unilateral self-paced reach-to-grasp movements (arm acceleration, hand opening and closing) to a small cylinder in the more and less affected arms of individuals with cervical SCI and in age-matched controls. We found that SCI subjects showed prolonged movement duration in both arms during arm acceleration, and hand opening and closing compared with controls. Notably, the more affected arm showed an additional increase in movement duration at the time to close the hand compared with the less affected arm. Also, the time at which the index finger and thumb contacted the object and the variability of finger movement trajectory were increased in the more compared with the less affected arm of SCI participants. Participants with prolonged movement duration during hand closing were those with more pronounced deficits in sensory function. The muscle activation ratio between the first dorsal interosseous and abductor pollicis brevis muscles decreased during hand closing in the more compared with the less affected arm of SCI participants. Our results suggest that deficits in movement kinematics during reach-to-grasp movements are more pronounced at the time to close the hand in the more affected arm of SCI participants, likely related to deficits in EMG muscle activation and sensory function. NEW & NOTEWORTHY Humans with cervical spinal cord injury usually present asymmetrical functional impairments in hand and arm function. Here, we demonstrate for the first time that deficits in movement kinematics during reaching and grasping movements are more pronounced at the time to close the hand in the more affected arm of spinal cord injury. We suggest that this is in part related to deficits in muscle activation ratios between hand muscles and a decrease in sensory function.

Essential gains and health after upper-limb tetraplegia surgery identified by the International classification of functioning, disability and health (ICF)

STUDY DESIGN

A questionnaire-based survey.

OBJECTIVES

To describe functional gains and health following upper-limb tetraplegia surgery using the International Classification of Functioning, Disability and Health (ICF) as a reference and to explore interconnections across different dimensions of functioning and health.

SETTING

A specialized center for advanced reconstruction of extremities at Sahlgrenska University Hospital, Gothenburg, Sweden.

METHODS

Fifty-seven individuals who participated in a satisfaction survey were included in the present study. Besides questions concerned with the respondents' satisfaction with different aspects of surgery, the measures included perceived overall health status (EQ-VAS) and achieved grip strength. Univariate analyses were used to explore interconnections between measures.

RESULTS

The gains could be subcategorized and linked to the ICF domains 'mobility', 'self-care', 'communication', 'domestic life', and 'community, social and civic life', with 'handling objects' and 'maneuvering a wheelchair' as the most frequently reported gains. The mean EQ-VAS score was 67±22. No significant correlation was shown between grip strength and activity gains, nor between grip strength and perceived overall health. The degree of satisfaction was, however, associated with self-reported overall health among participants.

CONCLUSION

The functional gains achieved after tetraplegia surgery could be applied to the ICF constructs' body functions/structures and activity with possible implications on participation. The overall health perception was relatively high and could be linked to the degree of satisfaction among participants. Muscle strength is not necessarily transferable to activity performance. This emphasizes the importance of addressing factors other than strength in the post-surgical rehabilitation and assessments.

Bimanual reach to grasp movements after cervical spinal cord injury

Injury to the cervical spinal cord results in bilateral deficits in arm/hand function reducing functional independence and quality of life. To date little research has been undertaken to investigate control strategies of arm/hand movements following cervical spinal cord injury (cSCI). This study aimed to investigate unimanual and bimanual coordination in patients with acute cSCI using 3D kinematic analysis as they performed naturalistic reach to grasp actions with one hand, or with both hands together (symmetrical task), and compare this to the movement patterns of uninjured younger and older adults. Eighteen adults with a cSCI (mean 61.61 years) with lesions at C4-C8, with an American Spinal Injury Association (ASIA) grade B to D and 16 uninjured younger adults (mean 23.68 years) and sixteen uninjured older adults (mean 70.92 years) were recruited. Participants with a cSCI produced reach-to-grasp actions which took longer, were slower, and had longer deceleration phases than uninjured participants. These differences were exacerbated during bimanual reach-to-grasp tasks. Maximal grasp aperture was no different between groups, but reached earlier by people with cSCI. Participants with a cSCI were less synchronous than younger and older adults but all groups used the deceleration phase for error correction to end the movement in a synchronous fashion. Overall, this study suggests that after cSCI a level of bimanual coordination is retained. While there seems to be a greater reliance on feedback to produce both the reach to grasp, we observed minimal disruption of the more impaired limb on the less impaired limb. This suggests that bimanual movements should be integrated into therapy.

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.

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.

Modulation of hand aperture during reaching in persons with incomplete cervical spinal cord injury

The intact neuromotor system prepares for object grasp by first opening the hand to an aperture that is scaled according to object size and then closing the hand around the object. After cervical spinal cord injury (SCI), hand function is significantly impaired, but the degree to which object-specific hand aperture scaling is affected remains unknown. Here, we hypothesized that persons with incomplete cervical SCI have a reduced maximum hand opening capacity but exhibit novel neuromuscular coordination strategies that permit object-specific hand aperture scaling during reaching. To test this hypothesis, we measured hand kinematics and surface electromyography from seven muscles of the hand and wrist during attempts at maximum hand opening as well as reaching for four balls of different diameters. Our results showed that persons with SCI exhibited significantly reduced maximum hand aperture compared to able-bodied (AB) controls. However, persons with SCI preserved the ability to scale peak hand aperture with ball size during reaching. Persons with SCI also used distinct muscle coordination patterns that included increased co-activity of flexors and extensors at the wrist and hand compared to AB controls. These results suggest that motor planning for aperture modulation is preserved even though execution is limited by constraints on hand opening capacity and altered muscle co-activity. Thus, persons with incomplete cervical SCI may benefit from rehabilitation aimed at increasing hand opening capacity and reducing flexor-extensor co-activity at the wrist and hand.

Kinematic characteristics of tenodesis grasp in C6 quadriplegia

STUDY DESIGN

Descriptive control case study.

OBJECTIVES

To analyze the kinematics of tenodesis grasp in participants with C6 quadriplegia and healthy control participants in a pointing task and two daily life tasks involving a whole hand grip (apple) or a lateral grip (floppy disk).

SETTING

France.

METHODS

Four complete participants with C6 quadriplegia were age matched with four healthy control participants. All participants were right-handed. The measured kinematic parameters were the movement time (MT), the peak velocity (PV), the time of PV (TPV) and the wrist angle in the sagittal plane at movement onset, at the TPV and at the movement end point.

RESULTS

The participants with C6 quadriplegia had significantly longer MTs in both prehension tasks. No significant differences in TPV were found between the two groups. Unlike control participants, for both prehension tasks the wrist of participants with C6 quadriplegia was in a neutral position at movement onset, in flexion at the TPV, and in extension at the movement end point.

CONCLUSION

Two main kinematic parameters characterize tenodesis grasp movements in C6 quadriplegics: wrist flexion during reaching and wrist extension during the grasping phase, and increased MT reflecting the time required to adjust the wrist's position to achieve the tenodesis grasp. These characteristics were observed for two different grips (whole hand and lateral grip). These results suggest sequential planning of reaching and tenodesis grasp, and should be taken into account for prehension rehabilitation in patients with quadriplegia.

A synthesis of best evidence for the restoration of upper-extremity function in people with tetraplegia

PURPOSE

Because upper-limb function represents overall function for individuals with tetraplegia, the restoration of upper-extremity function is exceedingly important for this population. The purpose of this review was to identify interventions that optimize upper-limb function after tetraplegia based on best available evidence.

METHODS

A search of MEDLINE, AMED, and PubMed with the search terms "hand function AND tetraplegia" and "upper limb function AND tetraplegia" found 384 articles. After elimination of duplicates and review of titles and abstracts, 43 studies were found to be applicable. Study quality of all applicable studies was assessed with a modified version of the Scottish Intercollegiate Guidelines Network for Cohort Studies methodology.

RESULTS

The applicable studies were organized into three categories: conventional therapies (CT), electrical stimulation therapies (ES), and surgical interventions (SI). The proportion of papers in each category that presented with sufficient methodological quality to contribute to best evidence was as follows: CT: 0/2; ES: 10/21; SI: 6/20.

CONCLUSIONS

ES therapies are beneficial as assistive technologies and as therapeutic intervention in the subacute phase of recovery. SIs are suitable for individuals who meet very specific criteria for tendon-transfer surgery. Further clinical trials are warranted for ES and SI therapies to substantiate prescription of therapeutics.

Sensory-motor equivalence: manual aiming in C6 tetraplegics following musculotendinous transfer surgery at the elbow

Cervical spinal lesions at C6 result in paralysis of the triceps brachii while leaving deltoid and elbow flexor function intact. We examined the spatial-temporal characteristics of goal-directed aiming movements performed by C6 tetraplegics who had undergone musculotendinous transfer surgery in which the posterior deltoid replaces the triceps as the elbow extensor. On some trials, liquid crystal goggles were used to eliminate vision of the limb and target upon movement initiation. Although tetraplegic participants achieved the same degree of movement accuracy/consistency as control participants, their movement times were longer regardless of whether the movements were made away from (elbow extension) or towards the body (elbow flexion). Longer movement times were related to lower peak velocities, and not the symmetry of the aiming profiles. The tetraplegic participants were no more dependent on visual feedback for limb regulation than control participants. Although the characteristics of the movement trajectories were surprisingly similar, in both vision conditions, tetraplegics required more real and proportional time to reduce spatial variability in the limb's trajectory for elbow extensions. Our results indicate that the sensorimotor system is adaptable and that the representations governing limb control are not muscle specific.