Intermuscular coupling and postural control in unilateral transfemoral amputees - a pilot study^.

Area of Science:

• Biomechanics
• Neuroscience
• Rehabilitation Engineering

Background:

• Postural balance is crucial for upright standing and is often impaired in individuals with lower-limb pathologies.
• Center of pressure (CoP) dynamics and electromyography (EMG) signal analysis are key methods for investigating motor control and balance mechanisms.
• Unilateral transfemoral amputation significantly impacts postural control and neuromuscular strategies.

Purpose of the Study:

• To investigate the differences in balance control and neuromuscular coordination between unilateral transfemoral amputees and able-bodied individuals during quiet standing.
• To explore the effects of visual conditions (eyes open/closed) on these parameters.
• To identify potential neuromuscular adaptations following amputation.

Main Methods:

• Combined analysis of center of pressure (CoP) dynamics and electromyography (EMG) coherence between trunk and lower limb muscles.
• Utilized the entropic half-life (EnHL) method to quantify CoP adjustment dynamics and EMG-EMG coherence.
• Compared 5 unilateral transfemoral amputees with 5 age-matched able-bodied controls under eyes open and eyes closed conditions.

Main Results:

• Amputees demonstrated higher CoP adjustment dynamics (lower EnHL values) than controls, particularly in the intact limb.
• EMG-EMG coherence was generally lower in amputees across most muscle pairs and visual conditions.
• Distinct correlations between CoP dynamics and EMG-EMG coherence were observed between the amputee and control groups.

Conclusions:

• Unilateral transfemoral amputation leads to significant alterations in neuromuscular control strategies for maintaining balance.
• These findings suggest the development of specific adaptations in response to limb loss.
• Understanding these adaptations is vital for designing advanced prosthetic limbs and optimizing rehabilitation programs.