Speech disfluencies in typically developing Finnish-speaking children - preliminary results.

We investigated the speech disfluencies of 54 typically fluent Finnish-speaking children: 14 children randomly selected from a longitudinal study (age levels 2, 3, and 4 years), and 40 children from a cross-sectional study (age levels 6, 7, 8, and 9 years). Speech samples, collected during a semi-structured conversation, were analysed for disfluencies per 100 words and 100 syllables. No significant within-age effect was found for the total frequency of disfluencies or disfluency types among the 2- to 4-year-olds. Across the 6- to 9-year-olds, between-group differences were found for the total frequency and type of disfluencies. Clinically relevant was that the criterion to distinguish normally fluent children from those who stutter, i.e., <3 stuttering-like disfluencies (SLD) per 100 syllables, was applicable in all age groups whereas the criterion <3SLD per 100 words was not. Consequently, these preliminary results suggest that different guidelines are needed for defining normal disfluency from stuttering in different languages.

Atypical pattern of discriminating sound features in adults with Asperger syndrome as reflected by the mismatch negativity.

Asperger syndrome, which belongs to the autistic spectrum of disorders, is characterized by deficits of social interaction and abnormal perception, like hypo- or hypersensitivity in reacting to sounds and discriminating certain sound features. We determined auditory feature discrimination in adults with Asperger syndrome with the mismatch negativity (MMN), a neural response which is an index of cortical change detection. We recorded MMN for five different sound features (duration, frequency, intensity, location, and gap). Our results suggest hypersensitive auditory change detection in Asperger syndrome, as reflected in the enhanced MMN for deviant sounds with a gap or shorter duration, and speeded MMN elicitation for frequency changes.

Speech-feature discrimination in children with Asperger syndrome as determined with the multi-feature mismatch negativity paradigm.

OBJECTIVE: Asperger syndrome, belonging to the autistic spectrum of disorders, involves deficits in social interaction and prosodic use of language but normal development of formal language abilities. Auditory processing involves both hyper- and hypoactive reactivity to acoustic changes. METHODS: Responses composed of mismatch negativity (MMN) and obligatory components were recorded for five types of deviations in syllables (vowel, vowel duration, consonant, syllable frequency, syllable intensity) with the multi-feature paradigm from 8-12-year old children with Asperger syndrome. RESULTS: Children with Asperger syndrome had larger MMNs for intensity and smaller MMNs for frequency changes than typically developing children, whereas no MMN group differences were found for the other deviant stimuli. Furthermore, children with Asperger syndrome performed more poorly than controls in Comprehension of Instructions subtest of a language test battery. CONCLUSIONS: Cortical speech-sound discrimination is aberrant in children with Asperger syndrome. This is evident both as hypersensitive and depressed neural reactions to speech-sound changes, and is associated with features (frequency, intensity) which are relevant for prosodic processing. SIGNIFICANCE: The multi-feature MMN paradigm, which includes variation and thereby resembles natural speech hearing circumstances, suggests abnormal pattern of speech discrimination in Asperger syndrome, including both hypo- and hypersensitive responses for speech features.

Auditory stream segregation in children with Asperger syndrome.

Individuals with Asperger syndrome (AS) often have difficulties in perceiving speech in noisy environments. The present study investigated whether this might be explained by deficient auditory stream segregation ability, that is, by a more basic difficulty in separating simultaneous sound sources from each other. To this end, auditory event-related brain potentials were recorded from a group of school-aged children with AS and a group of age-matched controls using a paradigm specifically developed for studying stream segregation. Differences in the amplitudes of ERP components were found between groups only in the stream segregation conditions and not for simple feature discrimination. The results indicated that children with AS have difficulties in segregating concurrent sound streams, which ultimately may contribute to the difficulties in speech-in-noise perception.

Similarities in the phenotype of the auditory neural substrate in children with Asperger syndrome and their parents.

Asperger syndrome (AS) is a developmental disorder of brain function characterized by deficits in social interaction including difficulties in understanding emotional expressions. Children with AS share some of the behavioural characteristics with their parents and AS seems to run particularly in the male members of the same families. The aim of the present study was to determine whether similarities could be found between children with AS and their parents at central auditory processing. It was found that in children with AS the sound encoding, as reflected by the exogenous components of event-related potentials, was similarly abnormal as in both their mothers and fathers. However, their abnormal cortical auditory discrimination, as indexed by the prolonged latency of the mismatch negativity, resembled that of their fathers but not that of their mothers. The present results suggest that complex genetic mechanisms may contribute to auditory abnormalities encountered in children with AS.

Language development in very low birth weight preterm children: a follow-up study.

The language development of 17 very low birth weight (VLBW) preterm children was compared with that of matched controls at the ages of 2 and 4 years. At the age of 2 years, the VLBW preterm children achieved significantly lower scores in the language comprehension test than their matched controls. In addition, they used shorter and more immature sentences. At the age of 4 years, difficulties in the VLBW preterm children manifested as deficiencies in language comprehension, naming and auditory discrimination. The language test results at the age of 2 years significantly correlated with those at the age of 4 years, but mainly in the preterm group. The highest and most frequent correlations were found between the language test scores at 2 years and the auditory discrimination test scores at 4 years. The only significant correlation to be found in the control group was between the vocabulary test score at 2 years and the consonant discrimination test score at 4 years. Therefore, language development of the VLBW preterm children should be measured and monitored from toddler age onwards. Special attention should be paid to measurements of auditory processing. While the results of the present study, however, represent mainly the outcome in a group of VLBW preterm children with changes in the neonatal MRI, the results should not be generalized to all VLBW preterm children.