Hyperlexia has characteristics similar to autism, behavior disorder, language disorder, emotional disorder, Attention Deficit Disorder, hearing impairment, giftedness or, paradoxically, mental retardation.

To develop effective teaching strategies and more typical childhood development, it is important to differentiate hyperlexia from other disorders. A thorough speech and language pathologist who is familiar with the syndrome of hyperlexia is a crucial first step. Psychological tests which emphasise visual processes rathere than verbal skills aid in identifying hyperlexia.

Hearing, neurological, psychiatric, blood chemistry and genetic evaluations can be performed to rule out other disorders but are not needed to identify hyperlexia.

source: hyperlexia.org