ACQ_Vol_11_no_3_2009

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ACQ Volume 11, Number 3 2009 149
Mental health
Andrew
Whitehouse
Keywords
AUTISM
SPECIFIC
LANGUAGE
IMPAIRMENT
PRAGMATIC
LANGUAGE
IMPAIRMENT
DIAGNOSIS
ADULT
OUTCOME
underlying aetiology of each condition) and clinical practice
(identifying interventions that may be more effective with
different groups of individuals).
Differential diagnosis
The current diagnostic approach is to differentiate “specific
language impairments” (SLI) from “non-specific language
impairments”. The former category includes those children
whose difficulties are restricted to the language domain,
whereas the latter category includes difficulties that are
associated with a broader condition, such as autism.
“Textbook” cases of SLI and autism are relatively easy to
identify and differentiate. The broad communicative
difficulties of individuals with autism (affecting both structural
and pragmatic aspects of communication) contrast with SLI,
in which there is a relatively specific deficit in the
development of linguistic skills. However, research over the
past decade has raised concerns over the validity of this
diagnostic divide. For example, many children have
behavioural characteristics that could be considered
“intermediate” between SLI and autism. Autism, in particular,
is widely recognised as a broad spectrum of disorders,
ranging from autism at the severe end of the continuum, to
pervasive developmental disorder – not otherwise specified
(PDD-NOS; behaviours characteristic of autism, but not at a
quantitative and/or qualitative severity to reach full criteria for
autism) and Asperger syndrome (behaviours characteristic of
autism, without any clinically significant delay in language or
cognitive development) at the less severe end. The
spectrum-nature of this condition has led to the now widely
used term autism spectrum conditions (ASC), which refers to
individuals with either a diagnosis of autism or PDD-NOS. It
is also not uncommon to observe a child with pragmatic
difficulties, but without the repetitive behaviours and marked
social deficits that are required to meet criteria for an ASC.
Such children have led to the additional diagnostic category
of pragmatic language impairment (PLI). Originally referred to
as semantic-pragmatic disorder, there has been a transition
to the alternative label of PLI, particularly in the United
Kingdom, due to findings that semantic and pragmatic
deficits do not always occur in combination (Bishop, 1998).
Although the current paper will adopt ASC and PLI to refer to
the syndromes described above, it is important to note that
the terms are not currently recognised in international
diagnostic guidelines.
The jury is still out on the ecological validity of the PLI
diagnostic category. Perhaps the most comprehensive
Specific language impairment and autism are
considered distinct developmental disorders.
However, while “textbook” cases of these
conditions can be differentiated with little
difficulty, there is a substantial proportion of
children who display “intermediate”
characteristics. One such example is the
group of children who exhibit pragmatic
language difficulties in the absence of other
autism-like behaviours, so called pragmatic
language impairment. There is contention as
to whether the difficulties of these children are
best considered a mild form of autism, or
whether they represent a diagnostic category
in their own right (so-called pragmatic
language impairment). This paper highlights
current thinking in the diagnostic
differentiation of these disorders, using
evidence from a longitudinal study
investigating the language, psychosocial, and
mental health outcomes in adulthood of
children with each condition. The findings
reinforce the validity of the pragmatic
language impairment diagnosis, and suggest
that adult psychosocial outcomes can be
predicted from their childhood language
profile. Mental ill-health was one outcome that
was relatively common among the adults with
a history of a communication disorder,
suggesting that a good working knowledge of
psychiatric conditions is beneficial for speech
pathology practice.
Communication disorders are, by their very nature,
heterogeneous; it is rare to find two individuals with
identical difficulties. Part of the issue here is that
communication is a broad category, encompassing both
structural (e.g., phonology, morphology, and semantics) and
pragmatic aspects of language (i.e., how language is used
in context). One of the goals of research in this area has
been to provide “order”, by identifying diagnostic categories
into which children can be grouped. Differential diagnosis
has benefits for both research (e.g., helping to elucidate the
Differentiating between
childhood communication
disorders
Implications for language and psychosocial outcomes
Andrew Whitehouse