How to judge mental retardation

Patient's question:

Treatment situation
The child is 15 years old, why can't they think independently? How to speculate how they are mentally retarded!? How to speculate if the child has intellectual problems

Doctor's answer:

Strictly speaking, mental retardation is a group of symptoms caused by certain diseases or other harmful factors; it is not a distinct disease entity. In mild mental retardation, some patients may have brain atrophy, cerebral dysplasia, or associated ataxia. What are the characteristics of practice and memory in mentally retarded patients?
1. Sensory processing speed slows down; stimuli through the visual pathway are easier to process than sensory stimuli.
2. Severe concentration, with extremely narrow attention span.
3. Poor memory; it takes numerous repetitions to learn some skills, and without repeated practice, they are quickly forgotten.