Introduction: Neurodevelopmental Disorders

Abstract

In this issue, I’m glad to introduce neurodevelopmental disorders. The neurodevelopmental disorders are ‘a group of conditions with onset in the developmental period’, which are firstly introduced in American Psychiatric Association’s fifth edition of Diagnostic and Statistical Manual of Mental Disorders (DSM-5, APA, 2013) [1]. The disorders typically occur in early development and are characterized by developmental deficits that produce impairments of personal, social, academic, or occupational functioning. The deficits of disorders are widely ranged from very specific limitations of learning or communicative skills to global impairments of social interactions or intellectual function. Under the category of the neurodevelopmental disorders, as you know, six diagnostic entities are there. Intellectual disability (intellectual developmental disorder, formerly mental retardation) is characterized by deficits in general mental abilities, such as reasoning, problem solving, planning, abstract thinking, judgement, academic learning, and learning from experience, and also in adaptive functioning in comparison to an individual’s age-, gender-, and socioculturally matched peers. Recently the term ‘mental retardation’ is replaced with the term ‘intellectual disability’ by forensic, educational, and other professionals and public and advocacy groups. The communication disorders include language disorder, speech sound disorder, social (pragmatic) communication disorder, and childhood-onset fluency disorder (stuttering). The first three disorder are characterized by deficits in the development and use of language, speech, and social communication, respectively. Speech is the expressive production of sounds and includes an individual’s articulation, fluency, voice, and resonance quality. Language includes the form, function, and use of a conventional system of symbols (i.e., spoken words, sign language, written words, pictures) in a rule-governed manner for communication. Communication includes any verbal or nonverbal behavior that influences the behavior, ideas, or attitudes of another individual. The core features of language disorder are persistent difficulties in the acquisition and use of language across modalities (i.e., spoken, written, sign language, or other) due to deficits in comprehension or production. Speech sound disorder is characterized by persistent difficulty with speech sound production. Childhood-onset fluency disorder (stuttering) is characterized by disturbances of normal fluency and time patterning of speech, including sound and syllable repetitions, sound prolongation of consonants as well as vowels, broken words, audible or silent blocking, circumlocutions, words produced with an excess of physical tension. Social (pragmatic) communication disorder is a new category in DSM-5, which is characterized by a primary difficulty with language pragmatics, or the social use of language and communication, as manifested by deficits in understanding and following social rules of verbal and nonverbal communication, changing language to match context or the needs of listener and following rules for conversation and storytelling. Autism spectrum disorder (ASD) is a new category in DSM-5, which replaces pervasive developmental disorders (PDDs) in DSMIV. DSM-5 introduced the concept of spectrum derived from dimensionality. On the understanding that previously separate three disorders listed under the PDD rubric in DSM-IV are better con