Upper limb impairments associated with spasticity in neurological disorders

Area of Science:

• Neuroscience
• Rehabilitation Medicine
• Biomechanics

Background:

• Spasticity's impact on upper-extremity movement is poorly quantified in neurological disorders.
• This study investigates impaired arm movements in stroke and spinal cord injury (SCI) populations.

Purpose of the Study:

• Characterize arm movement impairments associated with spasticity in stroke and SCI.
• Compare voluntary arm movements between these two clinical groups to understand spasticity's effects and underlying mechanisms.

Main Methods:

• Quantified kinematics (trajectory, velocity, acceleration) and kinetics (isometric contractions) of rapid elbow extension.
• Assessed movement smoothness using two computational techniques in SCI, stroke (paretic and non-paretic limbs), and neurologically intact subjects.

Main Results:

• Significant kinematic, kinetic, and smoothness changes were observed in the paretic arm of stroke subjects compared to normal arms.
• No significant differences in most parameters were found between SCI and stroke subjects, except for movement smoothness.
• Extension smoothness was reduced in the paretic arm of stroke patients but normal in SCI patients.

Conclusions:

• Arm movement impairments are similar in spastic stroke and SCI patients, despite different injury origins.
• The non-paretic arm in stroke patients is comparable to healthy controls, making it suitable for comparative studies of the paretic arm.