A method for treating dyslexia or reading developmental disorder (RDD) in a patient in need thereof comprises administering botulinum toxin to the patient. The botulinum toxin may be administered by subcutaneous or intradermal injection. The subcutaneous or intradermal injection may be administered to and/or around the vicinity of a trigeminal nerve, a cervical nerve, a thoracic nerve, a lumbar nerve, and/or a sacral nerve of the patient. In infants or toddlers—from about birth to 5 years old, botulinum toxin is used to prevent or minimize damage to the developing brain that would result in dyslexia; in older children and adult patients with dyslexia, botulinum toxin will be used to reduce or eliminate their symptoms.