These are developmental disorders of neurobiological origin, characterized by learning difficulties which cannot be attributed to either an intellectual retardation, a physical or sensorial handicap, an unfavorable environment, such as socio-economic background, or to the presence of psycho-emotional difficulties.
 
These difficulties are in contradiction with the other domains of development which are normal.
They appear very early in life and interfere with normal and persistent development up to adult age.

Some of these disorders directly concerning learning difficulties in school include:
- Dyslexia
- Dysorthography
- Dyscalculia
- Dysgraphia
Others relating to oral language development are grouped under the term of Dysphasia.
Finally, others concern the programming and acquisition of learned gestures and correspond to dyspraxia.