Hyperlexia I: It happens when children developing without disabilities learn to read early and far above their expected level. Because other children eventually learn to read and catch up, and this condition is temporary.
2. Hyperlexia II: This type of hyperlexia occurs in children with autism. They are often obsessed with numbers and letters, preferring books and magnetic letters over other types of toys. They also frequently remember important numbers such as license plates and birth dates. These children usually have more typical signs of autism such as avoiding eye contact, lacking affection and being sensitive to sensory stimuli.‌
3. Hyperlexia III: This type is like hyperlexia II, but the symptoms decrease over time and finally disappear. Children with hyperlexia III generally tend to have excellent reading comprehension, but their verbal language development may be behind, and they also have remarkable memories. As compared to children with autism, children with hyperlexia III easily make contact and are outgoing and affectionate.