Glossary of terms: M

Macrocephaly

NAAR glossary

Excessive head size.

Megalencephaly

Dictionary of mental handicap, M Lindsey

Having a brain of unusually large size.

Metabolism

Black's medical dictionary, G Macpherson ed; 38th ed

This means tissue change and includes all physical and chemical processes by which the living body is maintained, and also those by which energy is made available for various forms of work.

Metarepresentation

DP

The ability to pretend and to understand pretence in others. This generally develops in the second year of human life but perhaps may be evident earlier. Alternatively, the ability to understand the relationship between a representation and what it represents. This links with metacognition or theory of mind. If metarepresentation is impaired then this affects the person's theory of mind.

Microcephaly

CaF directory of specific conditions and rare syndromes

Defect in the growth of the brain which causes it to be smaller than a normal brain.

Miller Dieker syndrome

CaF directory of specific conditions and rare syndromes

Neural migration disorder in which the convolutions of the cerebral cortex are either completely absent or reduced in number, giving the brain surface a smooth appearance. Problems include developmental delay, microcephaly and seizures.

Monoamine oxidase

Black's medical dictionary, G Macpherson ed; 38th ed

Monoamine oxidase (MAO) is a naturally occurring enzyme which is concerned in the breakdown of monoamines.

Monoamines

Black's medical dictionary, G Macpherson ed; 38th ed

Monoamines play an important part in the metabolism of the brain. There is some evidence that excitement is due to an accumulation of monoamines in the brain. Autistic behaviours might be related to an abnormal functional imbalance among monoamines either at a molecular level or at a system level.

Multiple complex developmental disorder

Handbook of autism and pervasive developmental disorders,
DJ Cohen and FR Volkmar eds; 2nd ed

Multiple complex (or multiplex) developmental disorder is a descriptive term for an early-onset syndrome in which there are basic deficits in affective modulation, capacity for relating, and stability of thinking. Characteristics of onset in infancy, sustained limitations in the capacity to form reciprocal relationships, and impoverished affective regulation suggest that MCDD might be appropriately placed in the category of PDD. Until the condition is characterised more clearly it is placed under the wider umbrella of PDD-NOS.

Multiple disabilities

DP

Simply the presence of more than one disability in the same individual. There are too many possible combinations to list, eg, autism and deafness, physical disability and Down syndrome.

Myelin

Children with autism, Trevarthen et al

A fat-like substance wrapped around nerve fibres, acting as an insulator and assisting the rapid transmission of nerve impulses.

Related resources

• Education jargon (England and Wales)
  
• Education jargon (Scotland)
  

• Can't find the term you're looking for? Try Research Autism's glossary