What are the symptoms of mental retardation?

Mental retardation is a phenomenon of intellectual retardation and is also the most common developmental disorder in children. It is mainly manifested in poor social adaptability, learning ability and self-care ability, which will have a great impact on the growth and interpersonal communication of children.

1. Mild mental retardation

The patient's IQ is between 50 and 69 years old, accounting for about 80% of MR. It is not easy to be detected in the early stages. In infancy, language and motor function development may be delayed, and there are no obvious signs of abnormalities in the development of the somatic and nervous systems. During school age, learning difficulties may gradually appear. Although language development is slightly delayed, social language is still acceptable, and the child can still take care of himself and engage in simple labor and technical operations. Difficulty calculating, reading, writing, applying abstract thinking, lack of flexibility and dependence on others. There are generally no physical abnormalities and the average life expectancy is close to that of normal people.

2. Moderate mental retardation

The patient's IQ is between 35 and 49 years old, accounting for about 12% of MR, and is usually discovered at the age of 3 to 5 years. The patients' development in all aspects in their early years is slower than that of normal children, especially the developmental delay in the ability to understand and use speech. Although they can learn to speak, their articulation is unclear, they lack vocabulary and concepts, their speech is simple, and their words often fail to express their ideas. They also lack abstract concepts, and their ability to discern the surrounding environment and their understanding of things tend to be superficial and fragmentary. When patients become adults, they can engage in simple, stereotyped or mechanical labor under supervision, and their intelligence level is equivalent to that of normal children aged 6 to 9. The patients have poor physical development, and organic causes can be found in most of them, but they can generally survive to adulthood.

3. Severe mental retardation

The IQ of patients is between 20 and 34 years old, accounting for about 8% of MR, and is usually discovered before the age of 20. Patients often have organic lesions of the body or central nervous system, or are accompanied by deformities, and have neurological symptoms such as epilepsy and cerebral palsy. Most patients are found to have obvious mental and motor developmental delays, low language development levels, unclear pronunciation, and some are even unable to speak shortly after birth. Patients have a small vocabulary, lack abstract thinking ability, have a vague concept of numbers, cannot learn with normal children, have uncoordinated emotional responses, and are easily impulsive. When the patient reaches adulthood, he or she can perform very simple physical work under care.

4. Extremely severe mental retardation

The patient's IQ is between 0 and 20 years old, accounting for 1% to 2% of MR. Patients have obvious neurodevelopmental disorders and physical deformities, extremely low intelligence levels, and no speech function. Most of them can neither speak nor understand what others say, and can only express their needs by screaming and crying. Their perception is significantly reduced, and they cannot distinguish between relatives and strangers. They have no defense or self-defense ability and do not know how to avoid danger. Daily life requires care from others. With special training, patients can only acquire extremely limited self-help capabilities. Most patients die young due to illness or poor survival ability.