What is inconsistency?
Child shows differing, repeated productions with multiple errors.
It’s associated with ongoing difficulties.
Obscures the child’s knowledge of sounds.
Makes the selection of therapy targets difficult.
Resistant to traditional therapy.
What is variability?
Productions that differ but can be attributed to factors in normal acquisition.
Usually decreases around 2-4 years.
If a child has low production accuracy then they will have high variability.
Characterised in 2 year olds by resolving error types. Usually only takes around 6 months.
Is thought to reflect underlying deficit in storage, assembly or retrieval of phonological output plan.
What are the four types of inconsistency?
- Resolving (R) - A correct production in a series or resolving error pattern. /debɹɐ/,/debɐ/,/debɐ/ for zebra.
- Phoneme Change (P) - Variation in phoneme realisations. One phoneme different each time. Zebra /debɐ/,/devɐ/,/dewɐ/.
- Phonotactic Change (T) - Variation in phonotactic structure. Child changes CV structure each time. Zebra /bebwɐ/,/bɐ/,/bewɐ/.
- Phoneme + Phonotactic Change (PT) Variation in phoneme realisations & phonotactic structure. Zebra /bɐjɐ/,/dɐ/,/eβi:/.
What is the most common type of inconsistency?
Resolving is the most common type because as the child gets older they make less sound mistakes.
What is an inconsistent speech disorder?
The child has a weak phonological plan - same word produced differently.
How is inconsistency scored? (DEAP)
Any inconsistency in the three attempts get a score of one.
No inconsistencies gets a score of 0.
Total number of inconsistencies/total number of attempts (usually 25) x 100
If score is more than 40% than child is inconsistent.
Change of morphology or addition of diminutisation doesn’t count as inconsistency. Neither does voicing change or use of another allophone.
What are the methods of classifying childhood speech disorders?
- Aetiology
- Age-related
- Linguistic theory - description of symptoms, surface structure.
Describe the aetiological areas of classification.
Functional - no known cause.
Organic - motor speech disorders (dysarthria, dyspraxia, tongue thrust)
Structural - Dentition, cleft palate, oro-facial abnormalities.
What are the age related classifications?
- Speech delay - child less than 9 years having persistent deletion and substitution errors or low intelligibility.
- Speech delay: Questionable Residual Errors - Children who are 6 - 8;11 whose error patterns only include common clinical distortions.
- Speech delay: residual errors - Children who are older than nine who continue to have speech errors.
- Speech delay: special populations - People who has psychosocial problems, deficits in the production mechanism etc.
Describe classification based on linguistic theory.
Articulation disorder - Generally few sounds in error, unable to produce the sound accurately.
Phonological delay - uses processes used by a child of a younger age.
What are the types of classification for phonological disorders?
- Consistent deviant - uses delayed and atypical processes consistently so that you are able to predict how a child will say a word. Have difficulty in abstracting phonological rules.
- Inconsistent deviant - used delayed and atypical processes but in addition shows inconsistency in assessment. Associated with phonological assembly/planning deficit. (Also associated with CAS).
What is Dodd’s classification system?
Same as those from linguistic theory section:
- Articulation disorder
- Phonological delay
- Phonological disorder - consistent
- Phonological disorder - inconsistent
Important to note that it is not transitional - children do not move from one category to the next.
Each subtype of speech disorder may occur at any age or stage in the child’s development.
What impact does inconsistency have on a child’s speech?
Very difficult to understand (even at single word level).
Makes them resistant to typical therapy.
