Specific Language Impairment

Specific Language Impairment is a developmental condition and changes over time. The causes of SLI are likely to be multifactorial (Bishop, 1992) with both extrinsic and intrinsic factors influencing the child’s development. The classical definitions have been arrived at by a process of exclusion. The following definition of SLI takes into account both intrinsic and extrinsic factors (Lees and Urwin, 1991).

A language disorder is that language profile which, although it may be associated with a history of hearing, learning, environmental and emotional difficulties, cannot be attributed to any one of these alone or even just the sum of these effects, and in which one or more of the following is also seen:

1. A close positive family history of specific difficulty in language development.
2. Evidence of cerebral dysfunction, either during development or by the presence of neurological signs.
3. A mismatch between the various subsystems of language in relation to other aspects of cognitive development.
4. A failure to catch these differences up with ‘generalised’ language help.
(The most common presentation is a combination of the above factors 1, 3 and 5. Factor 2 is rare).

Prevalence and Incidence

Varied reports of frequency are documented according to definition:

• 5% of children in the UK, eg 36, 000 in year 2 have SLI (Law et al, 2000)
• Estimated ratios of approximately 2.8 males to every female (Robinson, 1987).
• Many children with SLI experience severe long-term difficulties. More than 72% of children who had SLI at age five remained impaired at age 12 (Beitchman et al, 1994).

Source: RCSLT CQ3 Handbook