This study aims to evaluate, in hemiparetic patients, changes in muscle ultrasound structure about the focal treatment of spasticity with botulinum toxin type A. For this purpose, the analysis of the mean echo intensity will be carried out on ultrasound acquisitions, identifying the possible correlations between the muscle echogenicity, the variations in the pennation angle, and the length of the fascicles.

For image processing operations, ImageJ software was applied.

Inclusion Criteria:

• unilateral ischaemic or haemorrhagic stroke (documented with clinical examination and neuroradiological findings)
• presence of spasticity at lower limb muscles, at least grade 1+ in the modified Ashworth Scale 3.
• age ≥ 18 years

Exclusion Criteria:

• inability to walk before stroke
• presence of severe cognitive impairment
• presence of other musculoskeletal, neurological or cardiopulmonary impairment which can interfere with clinical findings
• presence of skin lesions that can contraindicate BoNT-A treatment
• previous surgical myotendinous elongation

Subjects already treated for focal post-stroke spasticity in our Unit