Definition: A condition, so far found only in girls, in which apparently normal early development is followed by partial or complete loss of speech and of skills in locomotion and use of hands, together with deceleration in head growth, usually with an onset between seven and 24 months of age. Loss of purposive hand movements, hand-wringing stereotypies, and hyperventilation are characteristic. Social and play development are arrested but social interest tends to be maintained. Trunk ataxia and apraxia start to develop by age four years and choreoathetoid movements frequently follow. Severe mental retardation almost invariably results.

Definition: A type of pervasive developmental disorder that is defined by a period of entirely normal development before the onset of the disorder, followed by a definite loss of previously acquired skills in several areas of development over the course of a few months. Typically, this is accompanied by a general loss of interest in the environment, by stereotyped, repetitive motor mannerisms, and by autistic-like abnormalities in social interaction and communication. In some cases the disorder can be shown to be due to some associated encephalopathy but the diagnosis should be made on the behavioural features. | Dementia infantilis Disi ...[+++]ntegrative psychosis Heller's syndrome Symbiotic psychosis

Definition: A disorder in which the main feature is a serious impairment in the development of motor coordination that is not solely explicable in terms of general intellectual retardation or of any specific congenital or acquired neurological disorder. Nevertheless, in most cases a careful clinical examination shows marked neurodevelopmental immaturities such as choreiform movements of unsupported limbs or mirror movements and other associated motor features, as well as signs of impaired fine and gross motor coordination. | Clumsy child syndrome Developmental:coordination disorder | dyspraxia

Definition: A specific developmental disorder in which the child's understanding of language is below the appropriate level for its mental age. In virtually all cases expressive language will also be markedly affected and abnormalities in word-sound production are common. | Congenital auditory imperception Developmental:dysphasia or aphasia, receptive type | Wernicke's aphasia | Word deafness

Constitutional delay of puberty Delayed sexual development

Definition: Disorders in which normal patterns of language acquisition are disturbed from the early stages of development. The conditions are not directly attributable to neurological or speech mechanism abnormalities, sensory impairments, mental retardation, or environmental factors. Specific developmental disorders of speech and language are often followed by associated problems, such as difficulties in reading and spelling, abnormalities in interpersonal relationships, and emotional and behavioural disorders.

Definition: A type of pervasive developmental disorder that is defined by: (a) the presence of abnormal or impaired development that is manifest before the age of three years, and (b) the characteristic type of abnormal functioning in all the three areas of psychopathology: reciprocal social interaction, communication, and restricted, stereotyped, repetitive behaviour. In addition to these specific diagnostic features, a range of other nonspecific problems are common, such as phobias, sleeping and eating disturbances, temper tantrums, and (self-directed) aggression. | Autistic disorder Infantile:autism | psychosis | Kanner's syndrome

Definition: A residual category for disorders in which there is some admixture of specific developmental disorders of speech and language, of scholastic skills, and of motor function, but in which none predominates sufficiently to constitute the prime diagnosis. This mixed category should be used only when there is a major overlap between each of these specific developmental disorders. The disorders are usually, but not always, associated with some degree of general impairment of cognitive functions. Thus, the category should be used when there are dysfunctions meeting the criteria for two or more of F80.-, F81.- and F82.

Definition: A specific developmental disorder in which the child's ability to use expressive spoken language is markedly below the appropriate level for its mental age, but in which language comprehension is within normal limits. There may or may not be abnormalities in articulation. | Developmental dysphasia or aphasia, expressive type

Definition: A specific developmental disorder in which the child's use of speech sounds is below the appropriate level for its mental age, but in which there is a normal level of language skills. | Developmental:phonological disorder | speech articulation disorder | Dyslalia Functional speech articulation disorder Lalling