Structural brain differences in pre-adolescents who persist in and recover from stuttering.

BACKGROUND: Stuttering is a complex speech fluency disorder occurring in childhood. In young children, stuttering has been associated with speech-related auditory and motor areas of the brain. During transition into adolescence, the majority of children who stutter (75-80%) will experience remission of their symptoms. The current study evaluated brain (micro-)structural differences between pre-adolescents who persisted in stuttering, those who recovered, and fluently speaking controls. METHODS: This study was embedded in the Generation R Study, a population-based cohort in the Netherlands of children followed from pregnancy onwards. Neuroimaging was performed in 2211 children (mean age: 10 years, range 8-12), of whom 20 persisted in and 77 recovered from stuttering. Brain structure (e.g., gray matter) and microstructure (e.g., diffusion tensor imaging) differences between groups were tested using multiple linear regression. RESULTS: Pre-adolescents who persisted in stuttering had marginally lower left superior frontal gray matter volume compared to those with no history of stuttering (ß -1344, 95%CI -2407;-280), and those who recovered (ß -1825, 95%CI -2999;-650). Pre-adolescents who recovered, compared to those with no history of stuttering, had higher mean diffusivity in the forceps major (ß 0.002, 95%CI 0.001;0.004), bilateral superior longitudinal fasciculi (ß 0.001, 95%CI 0.000;0.001), left corticospinal tract (ß 0.003, 95%CI 0.002;0.004), and right inferior longitudinal fasciculus (ß 0.001, 95%CI 0.000;0.001). CONCLUSION: Findings suggest that relatively small difference in prefrontal gray matter volume is associated with persistent stuttering, and alterations in white matter tracts are apparent in individuals who recovered. The findings further strengthen the potential relevance of brain (micro-)structure in persistence and recovery from stuttering in pre-adolescents.

Stuttering and gray matter morphometry: A population-based neuroimaging study in young children.

Stuttering is a developmental speech disorder originating in early childhood. We aimed to replicate the association of stuttering and structural morphometry using a large, population-based prospective cohort, the Generation R Study, and explore the neurobiological mechanism of stuttering in children. Twenty-six children with a history of stuttering and 489 fluent speaking peers (ages 6-9) were included in the MRI sub-study. Cortical and subcortical regions of interest were analyzed using linear regression models. Compared to fluent speakers, children with a history of stuttering had less gray matter volume in the left inferior frontal gyrus and supplementary motor area. Exploratory surface-based brain analysis showed thinner cortex in the left inferior frontal gyrus, and in bilateral frontal and parietal areas. These findings corroborate previous studies that reported aberrant brain morphometry in speech motor and auditory regions in children who stutter. Future research is needed to explore the causal nature of this association.

[Fifty years of treating stuttering in young children]. / Vijftig jaar behandeling van stotteren bij jonge kinderen.

Developmental stuttering involves a disruption in the smooth connection of sounds or syllables that is characterised by multiple interruptions within a word, such as repetitions of sounds, syllables and parts of words, elongation of words and blockades. During the course of the past fifty years, three phases can be distinguished in the management of developmental stuttering, characterised by a shift in stress from the environmental factors to the role of the organic, i.e. non-psychological, factors. Initially, the parents of toddlers and pre-school children were advised to pay no attention to stuttering behaviour. Then the problem would disappear the quickest of its own accord. After 1985, the stress came to be placed on reducing the level of expectations, for example by speaking to the child more slowly and using shorter and less complex sentences. Another new aspect was that the parents learned to discuss stuttering with the child in a sympathetic and accepting manner. Since 2000, an approach has been introduced in the Netherlands in which parents are taught to respond verbally to both fluent and non-fluent speech. Emphasis is given to rewarding fluent speech, such as in the Australian Lidcombe Program, but the parents are also taught to react to stuttered speech once in a while. At present, early treatment is accepted as a way of preventing chronic stuttering, even if this means that some children will be treated that would have recovered in any case and even though the exact yield is not yet clear. Clinical practice shows that early treatment almost always succeeds in limiting the severity of stuttering to a mild form.

Stuttering and communicative suitability of speech.

The purpose of the present study was to develop and evaluate an instrument for assessing the communicative suitability of speech (i.e., the speaking situation-dependent adequacy of speech as judged by listeners). Listeners judged the suitability of speech of people who stutter (N = 10) at three stages of treatment (before, immediately after, and 6 months after) and that of people who do not stutter (N = 10, the latter serving as a reference). The listeners rated the suitability of the speech, using a 10-point scale, for 10 speaking situations that supposedly make different demands, with listeners consisting of three groups: unsophisticated listeners (N = 17), clinicians specializing in the treatment of stuttering (N = 17), and stuttering listeners (N = 17). Results indicate that the rating instrument can be scored reliably. Analysis of variance for the ratings of the reference speakers showed that the factor "situation" had a significant effect on the suitability ratings, with more demanding situations receiving lower suitability scores than the less demanding ones. Also, the speech of the people who stutter was judged significantly less suitable than the speech of the reference speakers. Furthermore, unsophisticated listeners were considerably less tolerant in their judgments than clinicians and stuttering listeners. Findings suggest that communicative suitability is a promising criterion to further investigate, especially as it may apply to the objective evaluation of treatment outcome for stuttering.

Perceptual rating instrument for speech evaluation of stuttering treatment.

A rating instrument is described that can be used to assess the results of stuttering treatments. The instrument is designed for use with naive listeners. It yields a comprehensive and detailed description of the speech quality in terms of articulation, phonation, pitch, and loudness; in addition, it includes a naturalness scale. Analysis of ratings obtained with the instrument show that naturalness is a multidimensional characteristic. Moreover, the speech characteristics that determine the naturalness ratings appear to be different pretreatment, posttreatment, and at follow-up treatment. The psychometric characteristics of the instrument are analyzed in detail. It is concluded that mixing of samples of stutterers and nonstutterers in one rating experiment may artificially inflate the reliability of the ratings. Also, ratings on equal-appearing interval scales cannot be interpreted in an absolute sense. Solutions for this methodological problem are suggested.