Effect of linguistic factors on the occurrence of stuttering-like disfluency among Japanese-speaking preschool children who stutter.

This study aimed to investigate the linguistic factors involved in stuttering among Japanese-speaking preschool children. The participants included 10 Japanese children who stutter, with a mean age of 5 years and 9 months. Speech samples comprised spontaneous conversations of the participants with their parents for about 20 minutes. We compared the percentages of the occurrence of stuttering-like disfluencies (SLDs) at the word and sentence levels, using the Wilcoxon signed-rank test. The results showed no significant differences in SLDs based on syllable structure when comparing light and heavy syllables and comparing consonants and vowels in the initial position of each content word. SLDs occurred more frequently in the initial than non-initial position of words and in longer rather than shorter words. Additionally, SLDs occurred more frequently in sentences that contained more 'bunsetsu' (a kind of linguistic unit in Japanese). Our study is the first to show that both word and sentence-level factors could contribute to SLDs in preschool children who stutter in agglutinating languages, such as Japanese. This aspect is rarely reported in psycholinguistic studies based on stuttering occurrence in inflecting languages, such as English.

Treatment for School-Age Children Who Stutter: A Systematic Review of Japanese Literature.

PURPOSE: This systematic review identified and synthesized published research articles, written in Japanese, on the clinical effectiveness of a broad range of nonpharmacological interventions for school-age children who stutter. METHOD: A systematic review of Japanese literature published between January 1, 1980, and July 7, 2020, reporting interventions for school-age children who stutter, was carried out through a search of two databases (CiNii Article database and Japan Medical Abstract Society database) using the key words "stuttering" and "school-age" or "child" or "primary school students" or "children" or "school child" in Japanese. To be included in the review, the articles must report studies where data were subjectively reported by clinicians, where school-age participants were treated for developmental stuttering, where participants received interventions conducted by clinicians, and where quantitative outcomes (pre- and/or posttreatment) were measured; and they must be published in Japanese. RESULTS: Forty articles met all the inclusion criteria. Most articles adopted a case series or single-case study design. A total of 179 intervention programs were identified from all the articles and broadly classified into speech therapy, psychological therapy, interventions for modifying the child's environment, and others. CONCLUSIONS: Our systematic review provided a broad overview of the treatments used for school-age children who stutter in Japan. Future research should focus on gathering more reliable, systematic, and rigorous evidence to establish the effectiveness of stuttering treatments for school-age children and thereby develop evidence-based practices.