Speech impairment is one of several terms used to describe children's difficulties in developing typical speech. It refers to children who experience problems in using the full range of consonants and vowels that would be expected for their age. In addition, they may have difficulties with resonance (tone of the voice) and intonation which may further impact on intelligibility and social acceptance.
Although the term covers a range of severity and presentations, speech impairment should not be confused with other types of communication impairment such as language delay or disorder where children have difficulties with language comprehension, vocabulary development, word finding and sentence construction; social interaction problems, including autism; stuttering or voice disorder.
Indeed it is not uncommon for speech problems to be associated with delayed or disordered language development.
Prevalence and aetiology
Speech impairment represents the largest single group referred to speech and language therapy (SLT). Prevalence estimates vary widely from 2.3 per cent to 24.6 per cent, dependent on the age of the child, the measure used and the cut-off point used to define speech impairment.
In most cases of speech impairment, there is no known cause. However, conditions associated with speech impairment include neurological disorders such as cerebral palsy and craniofacial malformations, particularly cleft palate.
Hearing impairment is another common cause, ranging from the profound effects of a severe sensorineural loss to the more subtle but persistent effects of otitis media. There is also some evidence to support a genetic component for some children. For unexplained speech impairment, there are a number of risk factors (see box).
|Risk factors for unexplained speech impairment|
Depending on aetiology and presentation speech impairment may be labelled as developmental dysarthria, developmental verbal dyspraxia, articulation impairment, phonological delay or phonological disorder.
When to refer to SLT
Identification of speech impairment is based on comparison with typical development, bearing in mind the considerable natural variation in children's speech development. When there is a concern, health visitors, who work closely with their SLT colleagues are usually able to screen preschool children's speech and assist in making a decision about the need for referral to SLT.
Those children with identified neurological, craniofacial or audiological conditions are likely to already be known to SLT at a specialist centre. However,the parents and children who will most typically present to the GP are those whose difficulties are more subtle or have not been picked up by other professionals.
For example, if a child presents with nasal sounding speech and has difficulties pronouncing consonants, a submucous cleft palate should be suspected, often associated with a history of middle ear and hearing problems and nasal regurgitation in infancy.
More unusually there may be a missed overt cleft palate.
The decision to make the referral to SLT depends on a number of factors. Specifically, the child's age, the degree of intelligibility and the older child's own attitude to the problem need to be considered.
As a general rule, if a child is aged over four and only a third of utterances are understood by an unfamiliar adult, then the child should be referred. In younger children it is better to refer to SLT if there is doubt.
It is not uncommon for families to present late to SLT with a history of having been told erroneously that the child will grow out of it. Intelligibility is unlikely to be affected where children have mild persistent immaturities such as a lisp or substitution of 'w' for 'r'.
However, if these cause the child distress and the child, rather than the parents, is motivated to change their speech, then referral is indicated.
Referral to SLT can be made directly; there is no need to refer to paediatrics or ENT first. It is helpful to refer to audiology at the same time as SLT if a recent hearing test has not been carried out, or the family reports concern about hearing.
SLT consists of a full diagnostic assessment to determine the subtype of speech impairment. Management varies dependent on the individual's presentation.
Intervention activities involve a range of listening and production tasks with activities given to parents or teachers to carry out at home or at school. Initial appointments with SLT usually take place in a NHS clinic or school.
Follow up appointments are arranged at regular intervals for a specified period of time.
SLTs can work closely with parent groups, schools and childcare providers to emphasise ways in which developing speech skills can be promoted.
Children with speech and language impairment have been shown to be at greater risk of literacy difficulties and there is evidence to suggest that when speech impairment persists into the school years, there can be a long-term effect on the child's academic and social outcomes.
There is also evidence to show that unemployment rates are higher amongst individuals with persistent speech impairment; there too is a higher representation of individuals with speech and language impairment within the justice system.
- Dr Wren is a consultant research speech and language therapist at North Bristol NHS Trust and Dr Sell is a consultant speech and language therapist and head of speech and language therapy at Great Ormond Street Hospital, London.
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4. Felsenfeld S, Broen, P, McGue, M.
J Speech Hear Res 1994; 37 (6): 1341-53.