Deep abdominal muscle activity following supratentorial stroke

Area of Science:

• Neurology
• Rehabilitation Science
• Biomechanics

Background:

• Supratentorial stroke often leads to motor deficits and altered muscle activation patterns.
• Deep abdominal muscle function, specifically transversus abdominus (TrA) and internal oblique (IO), is crucial for core stability and movement control.
• Understanding muscle activation post-stroke is vital for developing effective rehabilitation strategies.

Purpose of the Study:

• To assess the level and symmetry of deep abdominal muscle (TrA and IO) activation in individuals with subacute supratentorial stroke.
• To compare muscle activation patterns during a modified hip flexion task between stroke survivors and a healthy control group.
• To investigate potential compensatory mechanisms or overflow in abdominal muscle activation following stroke.

Main Methods:

• Electromyographic (EMG) activity of the TrA and IO muscles was recorded using fine-wire electrodes under ultrasound guidance.
• Participants included individuals with subacute supratentorial stroke (n=11) and age-matched controls (n=11).
• Participants performed standardized head lift and unilateral hip flexion tasks.

Main Results:

• No significant difference in TrA and IO activation amplitude was found during head lift between stroke and control groups, or between ipsilesional and contralesional sides.
• During unilateral hip flexion, both TrA and IO showed increased activation on both sides when the paretic leg was moved in the stroke group.
• In controls, muscle activity during hip flexion was higher ipsilateral to the moving leg; in stroke survivors, IO activity tended to be higher on the non-paretic side, regardless of the moving limb.

Conclusions:

• Deep abdominal muscle activation patterns are altered following supratentorial stroke, particularly during hip flexion.
• Increased TrA and IO activity during paretic leg movement may represent compensatory strategies to aid hip flexor activation or indicate neural overflow.
• These findings highlight the complex neuromuscular adaptations after stroke and inform targeted rehabilitation approaches for core and limb control.