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DEAP Test Standardization

The objective of this study is to provide a clinical test battery that will be a standardized and cost effective means of differential diagnosis of speech disorders of Irish children (3-6:11 year old range). The assessment and differential diagnosis of developmental speech disorders in children is a time-consuming business, and it is hampered in the Irish context by the lack of assessments standardised on Irish children. In 2002, Barbara Dodd and colleagues developed the Diagnostic Evaluation of Articulation and Phonology ( DEAP) (Dodd, Hua, Crosbie, Holm, Ozanne, 2002). The DEAP consists of five assessments: a diagnostic screen; an articulation assessment; an oro-motor assessment; a phonological assessment; an inconsistency assessment. It can be used for measuring changes in children’s phonological system over time in therapy. The DEAP has been standardized on samples of randomly selected children in schools and nurseries across the UK, and in Queensland, Australia. It provides qualitative and quantitative measures of speech performance, and its validity, reliability, and specificity have been demonstrated. As an effective means of screening and of differentiating between normally and delayed developing phonology, consistent and inconsistent phonology, and articulation disorders (functional and organic), the DEAP represents a major advance in cost effective paediatric phonology evaluation. ). However, English that is spoken in Ireland represents a wide variation from standard English, and within English as it is spoken in the UK or Australia. The DEAP requires standardisation on an Irish population to be truly effective for use in Ireland.

Generally, pronunciation errors in children’s speech are classified according to whether they are of linguistic or motor origin. Linguistic deficits arise when the phonological (sound) system is either delayed in development, characterised by an error pattern that is atypical, or by inconsistent errors. Motor or articulation errors are associated with organic oro-motor deficits (including e.g., dysarthria, cleft palate) or phonetic errors because of learning an atypical motor pattern. Most assessments of articulation and phonology rely on sampling single words, and few have been standardised on a normal population (none in Ireland). In addition, some assessments provide in-depth data about a developing phonological system but they are time consuming to administer and analyse. The screening test of the DEAP takes on average 5 minutes to administer, and the test battery in full generally takes c. 30-40 minutes to administer (depending on the child).

This research is shared between health service providers in the Speech & Language Therapy department of the Health Service Executive (Northern) Area (North Dublin and environs) and academic staff at Clinical Speech & Language Studies at Trinity College. The study is funded by the HRB, and involves testing of 200 randomly selected Irish children aged between 3;0-6;11 years. 80% of the sample will be drawn from the Dublin area, and 20% from regional areas to account for possible variation. The issue of bilingualism will be noted, whether children speak English as a first or second language, and some individual case studies can be done for this group. These include: (1) the issue of specifying no exclusion criteria on the basis of suspected speech difficulties or history of speech problems will be specified, therefore reflecting the true population; (2) as in the Australian sampling, socio-economic status will be estimated according to areas where the child is attending school, with 50% of children to be selected from middle class and 50% from a lower socio-economic area; (3) gender representation will be around 50/50; (4) If necessary, 10% of children tested will be re-tested for test-retest reliability index. Results will provide a product that can be used as a cost effective means of diagnostic screening and speech evaluation for therapeutic intervention in Ireland.

Margaret Leahy, Barbara Dodd