Intellectual disability, also formerly known as mental handicap, mental retardation or learning disability, refers to a significant impairment of cognitive and adaptive functions, with age of onset before 22 years . Patients have different forms of intellectual disability, which are permanent disabilities and thus have no cure. Before the age of 22, patients will have obvious deficiencies in adaptive behavior, and their personal learning and social adaptability will also be limited. However, in terms other than intelligence, such as emotional or physical abilities, most intellectually disabled people are the same as ordinary people.
One of the tests used to evaluate intellectual disability is the Intelligence Quotient Test or more popularly known as an IQ Test. According to the International Classification of Diseases, 10th Edition (ICD-10), intellectual disability based on IQ Test result can be divided into the following four levels:
IQ level is about 50 to 55 to approximately 70 (accounting for 85% of the total)
Approximate synonyms: Intellectual disability, mild; mild intellectual disability; mild mental retardation
IQ level is about 35 to 40 to 50-55 (accounting for 10% of the total)
Approximate synonyms: Intellectual disability, moderate; moderate intellectual disability; moderate mental retardation
IQ level is about 20 to 25 to 35-40 (accounting for 3.5% of the total)
Approximate synonyms: Intellectual disability, severe; severe intellectual disability; severe mental retardation
IQ level is below 20 -25 (about 1.5% of the total)
Approximate synonyms: Intellectual disability, profound; profound intellectual disability; profound mental retardation
The Maternal and Child Health Center under the Hong Kong Department of Health has a comprehensive children's physical and mental observation program to provide medical diagnosis, assessment and referral services to all children in Hong Kong. The purpose is to identify children with special educational needs as early as possible. Diagnostic methods may include:
Preliminarily judge the patient's intelligence level by asking patients or accompanying family members relevant questions and cooperating with the patient to complete the scale's parameters for listening, speaking, reading, writing and other contents.
Comprehensive assessment of the patient’s sensory, motor and reflex skills also involves observing the patient’s gait and eye movements.
Use of imaging techniques to determine organic brain conditions or malformations, its severity, and possible cerebrovascular disease
Congenital hypothyroidism (abnormally low levels of functional thyroid hormones at birth) can cause intellectual disability, so blood levels of thyroid-stimulating hormone (TSH), tri-iodothyronine (T3) and thyroxine (T4) are measured and appropriate treatment initiated.
Some cases of unexplained learning Disability may be genetically related. Doctors need to understand the patient's medical history in detail, including family history, and request for genetic testing to identify which specific genetic disease the patient may have. If necessary, parents of intellectually disabled children may also need to undergo genetic testing.
Excessive lead, mercury and cadmium build up in the body can damage the neurons and developing brain causing cognitive dysfunction and impaired patient behavior and adaptation.
There is no specific pharmacologic treatment for intellectual disabilty but drugs like the ones below can be used to relieve some of the symptoms and rehabilitation treatment can help integrate the patient into society:Medical treatment
Cognitive rehabilitation and skills training
Intellectual Disability is a challenging condition that entails multi-faceted approach to management to best prepare the patients for self-care and independence. Although patients may have limitations in their personal learning and social adaptability, they are usually no different from ordinary people in aspects other than intelligence, such as emotional or physical abilities. They need our understanding and assistance to better integrate into society, discover their strengths, and find jobs that suit them. If you find that your child or relative or friend may have intellectual disability, please feel free to inquire with our doctors.
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