Quantitative comparison of grasp and release abilities with and without functional neuromuscular stimulation in adolescents with tetraplegia

Development, Content Validity and Reliability of Upper Extremity Functional Skill Measure in C5-C7 Spinal Cord Injury

STUDY DESIGN

A methodological research design.

OBJECTIVE

To create an objective measure for assessing hand functions in C5-C7 spinal cord injury (SCI) and estimation of its content validity and internal consistency reliability.

METHOD

This study was executed in three phases. Phase 1 included a thorough review of the literature, semi-structured in-depth interviews of participants with tetraplegia and interviews of caregivers of SCI individuals and healthcare workers dealing with SCI to understand the hand functions of individuals with C5-C7 SCI. Phase 2 consisted of the development of the tool. The content validity ratio (CVR) method and the opinion of the expert validated the content of the upper extremity functional skill measure (UEFSM). Phase 3 included a quantitative evaluation of the tool which was done on a targeted group of 30 subjects with C5-C7 SCI.

RESULTS

Through the review of the literature and in-depth interview of the participants, 11 items were developed under four content areas: grasp, grip, pinch and gross movement. Items with a minimum CVR of 0.56 were retained at a significance level of p = 0.05 resulting in a 10-item tool for assessing the hand function of individuals with C5-C7 SCI categorized under four subscales. Pilot testing on 10 subjects reveals an average time of 2 minutes and 25 seconds to complete the task. The Cronbach's alpha was found to be 0.878.

CONCLUSION

UEFSM is a 10-item tool with good content validity and internal consistency reliability for the assessment of hand functions in individuals with C5-C7 SCI.

Clinically Significant Gains in Skillful Grasp Coordination by an Individual With Tetraplegia Using an Implanted Brain-Computer Interface With Forearm Transcutaneous Muscle Stimulation

OBJECTIVE

To demonstrate naturalistic motor control speed, coordinated grasp, and carryover from trained to novel objects by an individual with tetraplegia using a brain-computer interface (BCI)-controlled neuroprosthetic.

DESIGN

Phase I trial for an intracortical BCI integrated with forearm functional electrical stimulation (FES). Data reported span postimplant days 137 to 1478.

SETTING

Tertiary care outpatient rehabilitation center.

PARTICIPANT

A 27-year-old man with C5 class A (on the American Spinal Injury Association Impairment Scale) traumatic spinal cord injury INTERVENTIONS: After array implantation in his left (dominant) motor cortex, the participant trained with BCI-FES to control dynamic, coordinated forearm, wrist, and hand movements.

MAIN OUTCOME MEASURES

Performance on standardized tests of arm motor ability (Graded Redefined Assessment of Strength, Sensibility, and Prehension [GRASSP], Action Research Arm Test [ARAT], Grasp and Release Test [GRT], Box and Block Test), grip myometry, and functional activity measures (Capabilities of Upper Extremity Test [CUE-T], Quadriplegia Index of Function-Short Form [QIF-SF], Spinal Cord Independence Measure-Self-Report [SCIM-SR]) with and without the BCI-FES.

RESULTS

With BCI-FES, scores improved from baseline on the following: Grip force (2.9 kg); ARAT cup, cylinders, ball, bar, and blocks; GRT can, fork, peg, weight, and tape; GRASSP strength and prehension (unscrewing lids, pouring from a bottle, transferring pegs); and CUE-T wrist and hand skills. QIF-SF and SCIM-SR eating, grooming, and toileting activities were expected to improve with home use of BCI-FES. Pincer grips and mobility were unaffected. BCI-FES grip skills enabled the participant to play an adapted "Battleship" game and manipulate household objects.

CONCLUSIONS

Using BCI-FES, the participant performed skillful and coordinated grasps and made clinically significant gains in tests of upper limb function. Practice generalized from training objects to household items and leisure activities. Motor ability improved for palmar, lateral, and tip-to-tip grips. The expects eventual home use to confer greater independence for activities of daily living, consistent with observed neurologic level gains from C5-6 to C7-T1. This marks a critical translational step toward clinical viability for BCI neuroprosthetics.

Mechanical Performance of Actuators in an Active Orthosis for the Upper Extremities

The aim of the project OrthoJacket is to develop a lightweight, portable, and active orthosis for the upper limps. The system consists of two special designed fluidic actuators which are used for supporting the elbow function and the internal rotation of the shoulder. A new design of flexible fluid actuator (FFA) is presented that enables more design options of attaching parts, as it is allowed by conventional actuators with a stationary centre of rotation. This advantage and the inherent flexibility and the low weight of this kind of actuator predestined them for the use in exoskeletons, orthoses, and prostheses. The actuator for the elbow generates a maximum torque of 32 Nm; the internal rotation is supported with 7 Nm. Both actuators support the movement with up to 100% of the necessary power. The shells for the arm and forearm are made of carbon reinforced structures in combination with inflatable cushions.

An implanted upper-extremity neuroprosthesis using myoelectric control

PURPOSE

The purpose of this study was to evaluate the potential of a second-generation implantable neuroprosthesis that provides improved control of hand grasp and elbow extension for individuals with cervical level spinal cord injury. The key feature of this system is that users control their stimulated function through electromyographic (EMG) signals.

METHODS

The second-generation neuroprosthesis consists of 12 stimulating electrodes, 2 EMG signal recording electrodes, an implanted stimulator-telemeter device, an external control unit, and a transmit/receive coil. The system was implanted in a single surgical procedure. Functional outcomes for each subject were evaluated in the domains of body functions and structures, activity performance, and societal participation.

RESULTS

Three individuals with C5/C6 spinal cord injury received system implantation with subsequent prospective evaluation for a minimum of 2 years. All 3 subjects demonstrated that EMG signals can be recorded from voluntary muscles in the presence of electrical stimulation of nearby muscles. Significantly increased pinch force and grasp function was achieved for each subject. Functional evaluation demonstrated improvement in at least 5 activities of daily living using the Activities of Daily Living Abilities Test. Each subject was able to use the device at home. There were no system failures. Two of 6 EMG electrodes required surgical revision because of suboptimal location of the recording electrodes.

CONCLUSIONS

These results indicate that a neuroprosthesis with implanted myoelectric control is an effective method for restoring hand function in midcervical level spinal cord injury.

[Assessment of functional abilities, handicap and quality of life in patients with spinal cord injuries]

OBJECTIVES

A literature review of the methods of evaluating function, handicap and quality of life in patients with spinal cord injuries.

METHODS

The literature review was based on the available French and English articles published since 1990 in 3 databases: MEDLINE, Pascal and Embase.

RESULTS

The literature is dominated by descriptions of tools for evaluating functional limitations in motor deficiencies. Such descriptions involve the validation of generic tools for patients with spinal cord injuries or of specific tools during the evaluation of a particular intervention such as surgery of the tetraplegic hand or adaptation of technical help.

CONCLUSION

The tools to assess patients with spinal-cord injuries are sufficiently numerous and varied to allow us to evaluate physical, functional and psychosocial dimensions. Rigorous methodological validation is continuously at the base of those proposed tools and thus reinforces our choice to use them. Unfortunately, few evaluation tools for patients with spinal cord injuries have been published, translated into French and validated.

Timed motor test for wheelchair users: initial development and application in children with spinal cord injury

OBJECTIVE

The objective of this study was to describe the development and preliminary results of reliability testing of the timed motor test (TMT), a performance-based measure of functional status for children with a spinal cord injury (SCI) who use a manual wheelchair. This study will also provide pilot data using the TMT to examine the impact of thoracolumbosacral orthoses (TLSO) on function in children with a SCI.

STUDY DESIGN

Cross-sectional observational study. METHODS/PARTICIPANTS: This study enrolled 11 subjects with SCI. The TMT consisted of donning a shirt, donning pants, even transfers, uneven transfers, and propelling a wheelchair 80 feet and up a ramp of 45 feet. Nine subjects completed the TMT with and without a TLSO, and 6 subjects (4 of whom also completed the TMT with and without a TLSO) completed the reliability testing.

RESULTS

Except for donning pants, the intertester and intratester reliability of the TMT was fair-to-good with intraclass correlation coefficients (ICCs) of 0.60 or greater. When wearing a TLSO, participants were slower at donning a shirt, donning pants, performing even and uneven transfers, and hallway propulsion (P < 0.05). There was a preference for not wearing a TLSO for dressing and transfer skills.

CONCLUSION

In general, the TMT for wheelchair users had fair-to-good intertester and intratester reliability. Based on these pilot data, there was an increase in time to complete several functional tasks because of the use of a TLSO as measured by the TMT in children with a SCI.

Functional evaluation of natural sensory feedback incorporated in a hand grasp neuroprosthesis

We investigated whether automatic control of a hand grasp neuroprosthesis by means of signals from natural sensors in the skin of the index finger can mimic the natural control of grasp force in an important task of daily living, namely eating. We designed a simulated eating task with the same ratio of rest and activity as was found on average in a video analysis of three meals consumed in a social environment. An instrumented fork measured grasp force as well as the force in the long axis and perpendicular to the long axis at the tip of the fork. The simulated eating task was performed by a tetraplegic volunteer using a hand grasp neuroprosthesis both with and without use of feedback from the natural sensors. Further, 10 able-bodied volunteers performed the task with the same (lateral) grasp as the tetraplegic volunteer to obtain measures for improving the control strategy of the hand grasp neuroprosthesis. We have shown that a hand grasp neuroprosthesis incorporating natural sensory feedback can to some extent mimic the natural application of grasp force on a fork during simulated eating. The mean grasp force during active phases was higher than the mean grasp force during inactive phases. The mean grasp force applied during a simulated eating task was reduced by using the system with sensory feedback compared to using the system without sensory feedback.

Analyse critique des modalités d’évaluation des résultats de la chirurgie fonctionnelle du membre supérieur tétraplégique. Revue de la littérature sur les 50 dernières années

OBJECTIVE

To study the methods of assessment of upper limb functional surgery in the literature.

METHODS

The literature review relating to the years 1950-2002 was carried out with three data bases: Medline, Pascal, Embase. This review also involved a thorough study of non-indexed references.

RESULTS

Although many instruments or tests are used to assess outcome after surgery, their reliability, validity and responsiveness have not been adequately proven. Methodology appears to be the major failing of the various scales used to assess these patients. The conceptual models underlying the evaluation are all too often unspecified. There is a lack of pertinence of the selected tasks for tetraplegics. There is limited documentation of the guiding framework or conceptualisation. Furthermore, the process of item selection is often unknown. Scales or instruments are also deemed to be too insensitive to document the small but meaningful functional gains made by tetraplegics after functional surgery.

CONCLUSION

To answer the need for a specific assessment tool for tetraplegics who undergo functional surgery, we have developed a national, multicenter, prospective and longitudinal study based on two concepts: the first concept is related to Life Habits that are the activities of daily living and social roles recognised by the socio-cultural context of a person according to age, sex and social and personal identity. They include activities that should be accomplished on a daily basis (nutrition, fitness, personal care, communication, mobility, etc.). Life Habits presenting a significant level of disruption can create handicap situations. The second concept is in relation with Motor Capacities that correspond to the abilities of a patient to perform basic and functional tasks regardless of contextual factors (environmental and personal factors).

Prospective evaluation of biceps to triceps and deltoid to triceps for elbow extension in tetraplegia

PURPOSE

The purpose of this study was to evaluate and compare the deltoid to triceps and biceps to triceps transfers for restoration of elbow extension in young persons with tetraplegia.

METHODS

This was a prospective randomized study. Sixteen arms of 9 subjects between 8 and 20 years of age with cervical-level spinal cord injuries were assigned randomly to undergo either a deltoid to triceps transfer or a biceps to triceps transfer. All arms were followed-up prospectively for at least 2 years after surgery.

RESULTS

Elbow extension was restored in 8 arms via the deltoid and in 8 arms via the biceps transfers. At the 24-month follow-up evaluation 7 of the 8 biceps transfers produced antigravity strength (grade 3 or better); in contrast only one arm with the deltoid transfer was able to extend against gravity. There was a considerable but subclinical loss (no subject appreciated any functional deficit) of elbow flexion torque after both transfers. Three months after surgery the deltoid group showed a 51% loss of elbow flexion torque and the biceps group showed a 52% loss of elbow flexion torque. By 24 months after surgery both groups improved but still showed a loss of flexion torque (deltoid 32%, biceps 47%). After gaining elbow extension the subjects in both groups rated the performance of most activities of daily living (ADL) and all self-selected activities as better, as measured on the Modified University of Minnesota Tendon Transfer Functional Improvement Questionnaire and the Canadian Occupational Performance Measure, respectively. Likewise all subjects were more satisfied with performance of their goals after undergoing elbow extension reconstruction.

CONCLUSIONS

This study showed the benefits of restoring elbow extension in persons with tetraplegia and provided support for the biceps transfer as an alternative to the deltoid to triceps transfer in individuals with good brachialis and supinator strength.

Effect of training on contractile and metabolic properties of wrist extensors in spinal cord-injured individuals

Paretic human muscle rapidly loses strength and oxidative endurance, and electrical stimulation training may partly reverse this. We evaluated the effects of two training protocols on the contractile and metabolic properties of the wrist extensor in 12 C-5/6 tetraplegic individuals. The wrist extensor muscles were stimulated for 30 min/day, 5 days/week, for 12 weeks, using either a high-resistance (Hr) or a low-resistance (Lr) protocol. Total work output was similar in both protocols. The nontrained arm was used as a control. Maximum voluntary torque increased in the Hr (P < 0.05) but not the Lr group. Electrically stimulated peak tetanic torque at 15 HZ, 30 HZ, and 50 HZ were unchanged in the Lr group and tended to increase only at 15 HZ (P < 0.1) in the Hr group. Resistance to fatigue, however, increased (P < 0.05) in both Hr (42%) and Lr (41%) groups. Muscle metabolism was evaluated by (31)P nuclear magnetic resonance spectroscopy ((31)P-NMRS) during and following a continuous 40-s 10-HZ contraction. In the Hr group the cost of contraction decreased by 38% (P < 0.05) and the half-time of phosphocreatine (PCr) recovery was shortened by 52% (P < 0.05). Thus, long-term electrically induced stimulation of the wrist extensor muscles in spinal cord injury (SCI) increases fatigue resistance independent of training pattern. However, only the Hr protocol increased muscle strength and was shown to improve muscle aerobic metabolism after training. Muscle Nerve 27: 72-80, 2003

An advanced neuroprosthesis for restoration of hand and upper arm control using an implantable controller

An advanced neuroprosthesis that provides control of grasp-release, forearm pronation, and elbow extension to persons with cervical level spinal cord injury is described. The neuroprosthesis includes implanted and external components. The implanted components are a 10-channel stimulator-telemeter, leads and electrodes, and a joint angle transducer; the external components are a control unit and transmitter-receiver coil. The system has completed preclinical testing and has been implanted fully in 3 persons and partially in 1 person, all with tetraplegia caused by spinal cord injury at C5 and C6. The minimum follow-up time for any system component is 16 months. All subjects had improvements in grasp strength, range of motion, and ability to grasp objects and increased independence in activities of daily living. Each subject became a regular user of the neuroprosthesis and is satisfied with it. The implanted components have not caused any medical complications. The operation of the electrodes and sensors has been stable. The data show that this advanced neuroprosthetic system is safe and can provide grasping and reaching ability to individuals with cervical level spinal cord injury.

Efficacy of an implanted neuroprosthesis for restoring hand grasp in tetraplegia: a multicenter study

OBJECTIVE

To evaluate an implanted neuroprosthesis that allows tetraplegic users to control grasp and release in 1 hand.

DESIGN

Multicenter cohort trial with at least 3 years of follow-up. Function for each participant was compared before and after implantation, and with and without the neuroprosthesis activated.

SETTING

Tertiary spinal cord injury (SCI) care centers, 8 in the United States, 1 in the United Kingdom, and 1 in Australia.

PARTICIPANTS

Fifty-one tetraplegic adults with C5 or C6 SCIs.

INTERVENTION

An implanted neuroprosthetic system, in which electric stimulation of the grasping muscles of 1 arm are controlled by using contralateral shoulder movements, and concurrent tendon transfer surgery. Assessed participants' ability to grasp, move, and release standardized objects; degree of assistance required to perform activities of daily living (ADLs), device usage; and user satisfaction.

MAIN OUTCOME MEASURES

Pinch force; grasp and release tests; ADL abilities test and ADL assessment test; and user satisfaction survey.

RESULTS

Pinch force was significantly greater with the neuroprosthesis in all available 50 participants, and grasp-release abilities were improved in 49. All tested participants (49/49) were more independent in performing ADLs with the neuroprosthesis than they were without it. Home use of the device for regular function and exercise was reported by over 90% of the participants, and satisfaction with the neuroprosthesis was high.

CONCLUSIONS

The grasping ability provided by the neuroprosthesis is substantial and lasting. The neuroprosthesis is safe, well accepted by users, and offers improved independence for a population without comparable alternatives.

Implanted stimulators for restoration of function in spinal cord injury

Neuroprostheses that electrically stimulate paralyzed muscles provide functional enhancements for individuals with spinal cord injury and stroke such as standing and stepping, reaching and grasping, and bladder and bowel function. For chronic applications, implanted neuroprostheses lead to reliable, low-maintenance and patient-acceptable systems. The advantages of such systems are discussed followed by a generic description of implantable stimulators. Features of current first and second generation neuroprostheses developed at our centre are discussed followed by our experience in the application of these devices in the rehabilitation of individuals with spinal cord injury.

Reduction of costs of disability using neuroprostheses

The lifetime costs associated with spinal cord injury are substantial. Assistive technology that reduces complications, increases independence, or decreases the need for attendant services can provide economic as well as medical or functional benefit. This study describes two approaches for estimating the economic consequences of implanted neuroprostheses utilizing functional electrical stimulation. Life care plan analysis was used to estimate the costs of bladder and bowel care with and without a device restoring bladder and bowel function and to compare these with the costs of implementing the device. For a neuroprosthesis restoring hand grasp, the costs of implementation were compared to the potential savings in attendant care costs that could be achieved by the use of the device. The results indicate that the costs of implementing the bladder and bowel system would be recovered in 5 years, primarily from reduced costs of supplies, medications, and procedures. The costs of the hand grasp neuroprosthesis would be recovered over the lifetime of the user if attendant time was reduced only 2 hours per day and in a shorter time if attendant care was further reduced. Neither analysis includes valuation of the quality of life, which is further enhanced by the neuroprostheses through restoration of greater independence and dignity. Our results demonstrate that implantable neuroprosthetic systems provide good health care value in addition to improved independence for the disabled individual.

Kinematic assessment of manual skill following functional hand surgery in tetraplegia

To determine whether surgical key grip reinforcement actually leads to a better movement ability we developed a procedure for the kinematic analysis of manual skill following hand surgery in tetraplegia. The functional results of surgery in 5 cases were examined by the kinematic analysis of drawing movements using an electronic pen and a digitizer under 3 conditions: with eyes open, with eyes closed, and while performing a concurrent arithmetic task. Movement velocity and dysfluency (ie, the number of velocity changes per centimeter) were measured before and at several moments after surgery during subsequent rehabilitation. Both movement velocity and dysfluency showed good stability across repeated trials and were consistently affected by visual deprivation. Movement velocity showed a 39% increment between the first and last assessment. Although grip strength increased in all patients, it was not associated with the change of movement velocity. These results suggest that other factors (eg, deep sensibility, cognition, muscle coordination) play a critical role in the ability to use improved grip force for controlling drawing movements and emphasize the value of a kinematic assessment besides measuring isolated grip force in the evaluation of functional hand surgery.

Implanted functional electrical stimulation hand system in adolescents with spinal injuries: an evaluation

OBJECTIVE

To study the utility and functional benefits of an implanted functional electrical stimulation (FES) system for hand grasp and release in adolescents with tetraplegia secondary to spinal cord injuries.

DESIGN

Intervention study with before-after trial measurement with each subject as his or her own control.

SETTING

Nonprofit pediatric orthopedic rehabilitation facility specializing in spinal cord injury.

PARTICIPANTS

A convenience sample of five adolescents between 16 and 18 years of age with C5 or C6 level tetraplegia at least 1 year after traumatic spinal cord injury. Key muscles for palmar and lateral grasp and release were excitable by electrical stimulation.

INTERVENTIONS

A multichannel stimulator/receiver and eight electrodes were surgically implanted to provide stimulated palmar and lateral grasp and release. In conjunction with implantation of the FES hand system, surgical reconstruction in the form of tendon transfers, tendon lengthenings and releases, and joint arthrodeses was performed to augment stimulated hand function. Rehabilitation of the tendon transfers and training in the use of the FES hand system were provided.

MAIN OUTCOME MEASURES

Measurements of pinch and grasp force, the Grasp and Release Test (GRT), and an assessment of six activities of daily living (ADL) were administered before implantation of the FES hand system and at regular follow-up intervals. Results of the stimulated response of individual muscles and surgical reconstruction were evaluated using standard and stimulated muscle testing techniques and standard assessment of joint range of motion. All subjects completed followup testing.

RESULTS

Lateral and palmar forces were significantly greater than baseline forces (p = .043). Heavy objects on the GRT could only be manipulated with FES, and FES increased the level of independence in 25 of 30 ADL comparisons (5 subjects, 6 activities) as compared to baseline. After training, FES was preferred in 21 of 30 comparisons over the typical means of task completion. Of the 40 electrodes implanted, 37 continue to provide excellent stimulated responses and all of the implanted stimulators have functioned without problems. The surgical reconstruction procedures greatly enhanced FES hand function by either expanding the workspace in which to utilize FES (deltoid to triceps transfer), stabilizing the wrist (brachioradialis to wrist extensor transfer), or stabilizing joints (intrinsic tenodesis transfer, FPL split transfer).

CONCLUSION

For five adolescents with tetraplegia, the combination of FES and surgical reconstruction provided active palmar and lateral grasp and release. Laboratory-based assessments demonstrated that the FES system increased pinch force, improved the manipulation of objects, and typically increased independence in six standard ADL as compared to pre-FES hand function. The study also showed that the five adolescents generally preferred FES for most of the ADL tested. Data on the benefits of the implanted FES hand system outside of the laboratory are needed to understand the full potential of FES.

Spinal cord injury rehabilitation. 3. Functional outcomes

This self-directed learning module highlights new advances in this topic area. It is part of the chapter on spinal cord injury rehabilitation in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation. This article contains information about mobility, ambulation, upper extremity function, bowel management, and technology to enhance function in the community. New advances covered in this section include functional electrical stimulation for enhancing mobility and upper extremity function.