To compare and analyze the clinical characteristics of children with delayed language acquisition due to two different diagnoses, which were specific language impairment (SLI, a primarily delayed language development) and global developmental delay (GDD, a language delay related to cognitive impairment).
Among 1,598 children who had visited the developmental delay clinic from March 2005 to February 2011, 467 children who were diagnosed with GDD and 183 children who were diagnosed with SLI were included in this study. All children were questioned about past, family, and developmental history, and their language competences and cognitive function were assessed. Some children got electroencephalography (EEG), in case of need.
The presence of the perinatal risk factors showed no difference in two groups. In the children with GDD, they had more delayed acquisition of independent walking and more frequent EEG abnormalities compared with the children with SLI (p<0.01). The positive family history of delayed language development was more prevalent in children with SLI (p<0.01). In areas of language ability, the quotient of receptive language and expressive language did not show any meaningful statistical differences between the two groups. Analyzing in each group, the receptive language quotient was higher than expressive language quotient in both group (p<0.01). In the GDD group, the Bayley Scales of Infant Development II (BSID-II) showed a marked low mental and motor quotient while the Wechsler Intelligence Scale showed low verbal and nonverbal IQ. In the SLI group, the BSID-II and Wechsler Intelligence Scale showed low scores in mental area and verbal IQ but sparing motor area and nonverbal IQ.
The linguistic profiles of children with language delay could not differentiate between SLI and GDD. The clinicians needed to be aware of these developmental issues, and history taking and clinical evaluation, including cognitive assessment, could be helpful to diagnose adequately and set the treatment plan for each child.
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Objective: The purpose of this study is to determine clinical and phonological characteristics of the patients with specific language impairment (SLI).
Method: Subjects were 24 SLI patients without known mental retardation, cerebral palsy, epilepsy, hearing loss or structural brain lesion and 23 normal children. Developmental history, oropharyngeal abnormality, and brainstem auditory evoked potentials were obtained in SLI patients. Receptive language age and quotient were assessed by Peabody picture vocabulary test. Phonetic characteristics of subjects were analysed using Visi-PitchⰒ and computerized speech laboratory.
Results: In perceptual evaluation, 32.3% of SLI patients showed incomplete articulation pattern. The patterns of incomplete articulation were substitution, distortion, nasalization, and addition. The receptive language of SLI patients (0.89⁑0.28) was significantly lower than control group (1.16⁑0.18). In Visi-PitchⰒ analysis, diadochokinetic rate and maximal phonation time were decreased in SLI patients. The total duration of three syllables in SLI patients were significantly prolonged, especially for bilabial heavily asperated and glottalized consonants and alveolar and velar slightly asperated, heavily asperated, and glottalized consonants.
Conclusion: The patients with SLI showed characteristic defect in articulation as well as expressive and receptive language delayment. This articulatory defect may be resulted from disturbance of central programming and coordination of articulation. The objective and quantitative analysis of Phonological characteristics using computerized speech system in SLI patients can contribute to diagnose and evaluate the treatment outcome for the patients.
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