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

Exp Brain Res, 2015 · DOI: 10.1007/s00221-014-4163-y · Published: March 1, 2015

Spinal Cord Injury Neurology Rehabilitation

Simple Explanation

This study investigates how people with incomplete cervical spinal cord injuries (SCI) control their hand opening when reaching for objects. The research focuses on whether they can still adjust their hand aperture (the distance between thumb and fingers) according to the size of the object, and how their muscle activity differs from able-bodied individuals. The findings reveal that while individuals with SCI have a reduced maximum hand opening, they maintain the ability to scale their hand aperture according to object size. However, they employ different muscle coordination strategies compared to able-bodied individuals, indicating the nervous system's adaptability after injury. These results suggest that rehabilitation strategies should focus on increasing hand opening capacity and reducing abnormal muscle co-activity in the wrist and hand. This can potentially improve hand function and the ability to perform daily tasks for individuals with SCI.

Study Duration

Not specified

Participants

8 SCI, 8 able-bodied

Evidence Level

Level 2: Experimental study

Key Findings

1
Individuals with cervical SCI have a significantly reduced maximum hand aperture compared to able-bodied controls.
2
Persons with SCI preserved the ability to scale peak hand aperture with ball size during reaching.
3
Persons with SCI used distinct muscle coordination patterns that included increased co-activity of flexors and extensors at the wrist and hand compared to AB controls.

Research Summary

The study aimed to quantify the extent to which object-specific hand aperture modulation is preserved in persons with incomplete cervical SCI. The results demonstrate that individuals with cervical SCI preserved the ability to scale hand aperture with object size, yet the magnitude of hand opening and the degree of aperture scaling as well as muscle coordination patterns they used were distinct from AB subjects. These findings may help guide new directions for rehabilitation and intervention development for persons with cervical SCI.

Practical Implications

Rehabilitation Strategies

Rehabilitation should aim at increasing hand opening capacity.

Targeted Therapy

Therapeutic approaches like mass practice and electrical stimulation may be merited.

Compensatory Strategies

Increased EMG co-activity may stiffen the wrist joint for greater stability, representing a compensatory strategy.

Study Limitations

1
The contribution of intrinsic hand muscles was not quantified.
2
Compensatory strategies of the arm in preparation for reach-to-grasp were not assessed.
3
The extent to which preservation of motor pathways is necessary remains unclear.

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