CHAPTER 30
Language Disorders
Many specific language impairments are associated with increased rates
of child psychiatric problems. This is not surprising, for three reasons.
First, language impairments and psychiatric problems may sometimes
share a common origin in brain abnormalities that interfere with ‘higher
functions’. Second, language dominates our lives: it is a powerful tool for
thought and problem solving; it is our primary means for obtaining what
we want from others; and it plays a key role in social cohesion, with
human conversation functioning rather like mutual grooming among
chimpanzees. Consequently, language impairments are likely to be
frustrating and isolating. Finally, the same set of social communication
difficulties may be construed as a language disorder by a speech-language
therapist and as a psychiatric disorder by a mental health professional; the
timber merchant, the botanist and the artist do not see the same tree.
Epidemiology
Specific language impairment(SLI) refers to language impairments that occur
in the context of otherwise normal development and that are not part
of a recognised syndrome; thus, a child would not be said to have SLI if
he or she has an intellectual disability or Landau-Kleffner syndrome (see
below). Estimates of the prevalence of SLI diverge widely, largely reflect-
ing differences in the definition employed. At one extreme, severe and
persistent disorders that result in substantial social impairment and occur
in children of normal intelligence are quite rare, with a prevalence that is
probably under 0.1%. At the opposite extreme, the prevalence of broadly
defined language disorders may be as high as 15–25%, though many of
these children have relatively minor delays or articulation problems that
result in little or no social impairment and that resolve without treatment.
Between the two extremes, significant language problems may be present
in roughly 1–5% of schoolchildren. No matter which definition is used,
there is a substantial male excess for all developmental language disorders.
Child and Adolescent Psychiatry, Third Edition. Robert Goodman and Stephen Scott.
©c2012 Robert Goodman and Stephen Scott. Published 2012 by John Wiley & Sons, Ltd.
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