Diagnosing spasticity in neonates involves a comprehensive neurological examination by a healthcare professional. This may include observing the babyâs movements, muscle tone, and reflexes. Advanced diagnostic tools such as Magnetic Resonance Imaging (MRI) and ultrasound may be used to identify any underlying brain abnormalities. Early signs of spasticity can include stiff or rigid muscles, exaggerated reflexes, and difficulty with motor skills.