Analysis of the Correlation Between Ultrasound Imaging and Functional Parameters in the Medial Gastrocnemius Muscle in Post-stroke Patients With Spasticity in the Lower Limb

The goal of this observational study is to understand the impact of spasticity on muscle changes and functional performance in stroke patients with lower limb spasticity in comparison to non-stroke individuals. The main questions it aims to answer are:

* How does spasticity affect muscle changes and lower limb functional performance in stroke patients?
* How do structural and textural parameters in ultrasound images differ between spastic stroke patients and non-stroke individuals?

Participants will undergo ultrasound evaluation of their leg muscles to measure structural and textural parameters. They will also take part in functional assessments to assess their performance in activities related to lower limb mobility.

Researchers will compare the structural and textural ultrasound parameters between stroke patients and non-stroke individuals to determine any notable differences. The study aims to identify the relationship between muscle changes, spasticity, and functional performance in stroke patients.

Cerebrovascular Accident (CVA) or stroke is one of the leading causes of morbidity and disability worldwide. Spasticity is a common complication in patients with CVA, affecting between 43.2% and 49.5% of patients in the first six months. It can interfere with movement and cause discomfort, pain, joint contracture, and abnormal limb posture. Ankle spasticity is particularly problematic for gait recovery.

Computed tomography (CT) and magnetic resonance imaging (MRI) are considered the gold standard for measuring muscle mass, but their use is not practical due to patient discomfort, radiation exposure, and high costs. Ultrasound is presented as an effective and low-cost tool for evaluating muscle tissues.

Previous research has analyzed architectural changes in spastic muscles in hemiplegic patients and found conflicting results regarding muscle thickness and fascicle length. Further studies are needed to better understand the relationship between muscle changes and weakness, spasticity, and functional performance of the lower limbs.

This study aims to analyze the relationship between muscular architecture and echotexture parameters, and the functional parameters of the medial gastrocnemius muscle in patients with spasticity in the lower limb after a stroke and compare them with non-stroke subjects.

Comparing the affected side with the supposedly healthy side of stroke patients will allow for a better understanding of the structural changes that occur on both sides.

Studying structural changes in patients with chronic spasticity after a stroke can help healthcare professionals better understand the impact of this condition on muscle function and develop personalized treatment plans. Ultrasound can be a useful tool to improve the effectiveness of rehabilitation interventions in stroke survivors.

Eligibility Criteria:
Group of patients diagnosed with ischemic or hemorrhagic stroke.

Inclusion Criteria:

* Age over 18 years
* Present spasticity in the plantar flexor muscles of the ankle as a result of a first unilateral ischemic or hemorrhagic stroke (excluding subarachnoid hemorrhage, as it is not truly a stroke) diagnosed by computed tomography or magnetic resonance imaging.
* Have more than 6 months of evolution since the onset of the cerebrovascular accident (chronic stroke).
* Degree of spasticity on the Modified Ashworth Scale (MAS): 1, 1+, 2, or 3.
* Be able to walk independently with or without assistance.

Exclusion Criteria:

* Other musculoskeletal or neurological disorders affecting the lower limb (bilateral stroke, peripheral neuropathy, peripheral nerve injury, myopathy, severe osteoarthritis, recent muscle injury, recent bone fracture, joint replacement, fixed contractures involving the affected leg, bone deformities of the lower limbs).
* Other neurological pathologies (e.g., ataxia or dystonia).
* Surgical intervention in the lower limb.
* Cognitive impairments that hinder study measurements.
* Other medical conditions that may interfere with data interpretation.

Group of non-stroke patients

Inclusion Criteria:

* Age over 18 years
* Be able to walk independently with or without assistance

Exclusion Criteria:

* Previous diagnosis of stroke.
* Presence of spasticity in any part of the body.
* Other musculoskeletal or neurological disorders affecting the lower limb (bilateral stroke, peripheral neuropathy, peripheral nerve injury, myopathy, severe osteoarthritis, recent muscle injury, recent bone fracture, joint replacement, fixed contractures involving the affected leg, bone deformities of the lower limbs).
* Other neurological pathologies (e.g., ataxia or dystonia).
* Surgical intervention in the lower limb.
* Cognitive impairments that hinder study measurements.
* Other medical conditions that may interfere with data interpretation.