Effects of Peripheral Somatosensory Stimulation Through Mechanical Pressure on Lower Limb Muscle Strength in Stroke Survivors

Effects of Peripheral Somatosensory Stimulation Through Mechanical Pressure on Lower Limb Muscle Strength in Stroke Survivors

Somatosensory information is essential for the motor system because when the central nervous system stops receiving afferent signals, it cannot use information about the state of the affected body part to plan or adjust movement. This phenomenon is known as sensory deafferentation, and it significantly affects motor function. This principle offers an opportunity to observe changes in strength through a peripheral proprioceptive stimulus that activates the muscular system with the aim of increasing recruitment. This would justify the implementation of proprioceptive input in approaches focused on motor learning in movement disorders resulting from cortical lesions such as stroke.

Objective: o determine whether the application of a peripheral proprioceptive stimulus to the neuromuscular motor points of the quadriceps increases strength and muscle activation during the squat movement in the affected limb of stroke survivors.

Methods:The design of this study is a randomized crossover clinical trial. All participants (n=36) will randomly receive both the Active and Sham proprioceptive stimulation.The proprioceptive stimulus will consist of intermittent mechanical pressure on the skin, localized at the neuromuscular motor points of the rectus femoris, vastus lateralis, and vastus medialis of the quadriceps. The tissue subjected to precise pressure in these highly innervated neuromuscular zones promotes the stimulation of kinesthetic cortical sensitivity. The outcome variable will be the assessment of Maximum Strength (MS) generated by the participant during the squat movement, from a 90º knee flexion position to full extension. At the moment of peak force, the mean velocity (MV) of the concentric phase of the movement and the maximum load the participant can move will be evaluated. The intervention, assessment, and recruitment will take place at AVAN Private Foundation Sabadell and Ricard i Fortuny Socio-Healthcare Center (CSSV RiF), Vilafranca.

Inclusion Criteria:

• Subjects with a diagnosis of unilateral hemispheric stroke (ischemic or hemorrhagic) confirmed by MRI or CT scan.
• At least 3 months must have passed since stroke onset.
• Ability to stand independently in a static position or to walk, regardless of whether assistance is needed.

Exclusion Criteria:

• Diagnosis of cognitive, visual, or cardiorespiratory disorder (including the presence of a cardiac pacemaker, heart failure, arrhythmia, or severe COPD)
• Orthopedic intervention in the lower limb
• Balance disorders of vestibular origin
• Skin diseases
• Botulinum toxin treatment within the past year