Glossary

An estimate of the number of cases of a condition within a population at a particular time. Prevalence is estimated by identifying how many people in a population sample have been diagnosed with the condition, or who would in principle meet the diagnostic criteria. Prevalence (e.g. of autism) does not necessarily indicate how many people have the condition: cases may go undetected due to factors such as low cultural awareness or limited availability of diagnostic services.

A prediction offered by a medical or other expert concerning the probable course and outcome of a disorder or condition.

Protodeclarative pointing is the use of pointing to draw someone else's attention to an object or item of interest, thus enabling an individual to share their interest with another. Thus a child might point to a bird so that his mother will look at it too. Children on the autism spectrum tend not to use this form of pointing, though they may use protoimperative pointing to indicate an object or item that they want or desire, such as pointing to a biscuit to indicate they want to have it.

Refers to the way the mind works to interpret information about the physical world and social world, and to respond appropriately. This includes perceptual processes such as recognising objects and events, and communicative process such as understanding language, perceiving and interpreting other people’s behaviour, including their gestures and facial expressions, and communicating both verbally and through one’s own behaviour.

This is the scientific study of the way the mind (generally the human mind) works and how this dictates and influences behaviour. Processes investigated include communication, memory, thinking and emotion.

Techniques that provide ways of measuring intelligence, language skills and other cognitive and behavioural capacities or traits.

The general well-being of a person and how they experience their life in terms of comfort, happiness and fulfilment. Factors affecting quality of life include health, relationships, employment and finance.

A questionnaire is a set of questions, often with multiple-choice answers or a scale (from ‘strongly agree’ to ‘strongly disagree’ for instance) to be completed. It can be used to explore attitudes, preferences or personality traits; it may also be used as part of the diagnostic procedure to find out about a person’s behaviour. (See also surveys.)

A systematic evaluation of an intervention in which participants are assigned randomly to intervention and ‘no treatment’ or ‘treatment as usual’ groups. This avoids biases in the way participants are allocated to groups, which could otherwise affect the outcome, making the intervention itself difficult to evaluate. RCTs are typically large-scale studies involving many participants. (See also intervention group; treatment as usual group.)

The process of receiving and understanding language which is spoken or written by others. Difficulty with receptive language means that the person has delay and/or difficulty in making sense of what other people say or write down. Problems are likely to include difficulty in understanding vocabulary or grammar, difficulty in distinguishing speech sounds and in understanding the meaning of sentences. Difficulty with receptive language is common on the autism spectrum and is often accompanied by expressive language difficulty. (See also expressive language.)