Dynamic Motor Compensations with Permanent, Focal Loss of Forelimb Force after Cervical Spinal Cord Injury

JOURNAL OF NEUROTRAUMA, 2013 · DOI: 10.1089/neu.2012.2530 · Published: February 1, 2013

Spinal Cord Injury Neurology Neurorehabilitation

Simple Explanation

This research examines how the body adjusts after a spinal cord injury in the neck that causes lasting weakness in arm muscles. Rats were given a spinal cord injury and their movements were studied for four months to see how their body compensated. The study found that the rats experienced a significant, permanent loss of force in their forelimb (front leg) after the injury. The rats started using their other legs more to make up for the lost strength, and they adjusted their movements over time to keep moving effectively. Researchers also discovered that the injury likely disrupted nerve signals from the brain and within the spinal cord itself, hindering the recovery of the affected forelimb.

Study Duration

4 Months

Participants

98 adult male Wistar rats

Evidence Level

Level II; Animal experimental study

Key Findings

1
A dramatic (50%), immediate and permanent loss of extensor force occurred in the forelimb but not in the hind limb of the injured side.
2
Overuse of both contralateral legs and ipsilateral hind leg was evidenced since 5 days postlesion.
3
Concurrent axotomy at C6 of brain descending axons and cervical propriospinal axons likely hampered spontaneous recovery of the focal neurological impairments.

Research Summary

This study provides a comprehensive quantitative description of motor deficits and compensations from the acute to the late chronic phase after C6 spinal cord hemisection. Permanent impairments were detected in the motor output of the spinal cord segments located immediately caudal to the lesion site, associated with chronic denervation of these segments. The study also shows that after recovering from the spinal shock, rats display only small functional gain but instead develop dynamic and complex neuro-mechanical compensations.

Practical Implications

Targeted Therapies

Future treatments for cervical SCI should consider the involvement of the cervical propriospinal system to improve outcomes.

Rehabilitation Strategies

Rehabilitation programs should focus on optimizing compensatory strategies, such as strengthening the less affected limbs.

Comprehensive Assessment

The study emphasizes the need for careful functional and anatomical studies to differentiate real functional recovery from sensorimotor compensations after SCI.

Study Limitations

1
The study was conducted on rats, and the results may not directly translate to humans.
2
The focus was on a specific type of spinal cord injury (C6 hemisection), limiting the generalizability to other types of SCI.
3
The study primarily assessed locomotion, and other aspects of motor function (e.g., fine motor skills) were not evaluated.

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