遲語兒兩歲至四歲的語言發展預測與社會情緒特性

Abstract

「兒童語言障礙」是學齡前兒童心智發展異常的主要類型之一。約有10%至15%兩歲兒童因語言表達發展遲緩而被診斷為「遲語兒」，「遲語兒」四歲時若語言發展達正常範圍則稱為「語言晚熟」，若他們四歲時的語言發展仍在遲緩範圍將被診斷為「兒童語言障礙」，另外兒童語言發展與他們的情緒行為表現和適應行為發展的關聯性密切，然而遲語兒童兩歲至四歲的情緒行為表現與適應行為發展尚不清楚。本研究旨從「個別差異穩定性」角度，探究「遲語兒」語言發展預測指標及社會情緒發展特性。研究採用「固定樣本貫時追蹤研究（panel study）」，追蹤遲語兒童（n = 35），以及配對年齡、性別、出生序及母語的一般兒童（配對組/語言正常組；n = 34），從兩歲到四歲的發展。本研究蒐集三波資料：兩歲、三歲及四歲；並於遲語兒童四歲時根據他們的語言表現區分「語言障礙」組（n = 12）與「語言晚熟」組（n = 20）。主要發現：第一，「語言障礙」與「語言晚熟」於兩歲、三歲及四歲的語言表現已大致呈現「語言障礙」＜「語言晚熟」，而且HLM分析發現這兩組兒童於兩歲至四歲呈現不同的語言變化樣貌；第二，兩歲能區分「語言障礙」與「語言晚熟」的預測指標有「接收性語言」、「快速連配」及「四聲聲調指認」。邏輯斯迴歸分析發現遲語兒童兩歲時，在這三個變項的得分越高，在四歲發展成兒童語言障礙的風險較低。而HLM分析發現「快速連配」與「四聲聲調指認」，能解釋遲語兒童兩歲至四歲語言變化率的群間差異；第三，遲語兒童在兩歲時情緒行達臨床須注意的比率已高於對照組，而且他們在兩歲與四歲的情緒行為特性具有跨時間點的發展穩定性，此外遲語兒童四歲時在「溝通領域」、「日常生活領域」及「社會領域」的適應行為仍不如同齡一般兒童，其中「母親教育程度」能顯著預測遲語兒童四歲「溝通領域」與「日常生活領域」適應行為。總結來說，兩歲遲語兒童語言發展與社會情緒特性已顯現個別差異性，且此個別差異性將持續穩定至四歲的學前階段。最後本研究根據研究結果進一步討論早期鑑定與療育的臨床意涵。

'Language Disorder' is one of the major neurodevelopmental impairments in preschool children. The age of four is the appropriate timing for diagnosing language disorder. Approximately about 10-15 percent of two-year-old children with delayed expressive language ability were diagnosed as “Late Talkers (LT)'. At age four, some late talkers grow into “late bloomers (LB),” whose language abilities turn out to be normal. However, other LTs whose language abilities continue to be delayed would be recognized as children with “Language Disorder (LD)”. LTs’ language abilities are also closely associated with their emotion and adaptive behaviors. Nevertheless, LTs' emotional and adaptive-behavioral development from age two to four remains unclear. The purpose of this longitudinal study was to examine the stability of individual differences among late-talking children in language, emotional and adaptive-behavioral characteristics from age two to four. This panel study recruited 35 two-year-old LT children and 34 typically developing children (TD) (matched with gender, chronological age, first language and birth order). The inclusion criteria for LT were expressive vocabulary size (measured by the Mandarin Communication Development Inventory-Toddler version) at or below the 15th percentile, and typical cognition and fine-motor abilities. Both groups of children were tested at the ages of two, three and four. The experimental instruments included the word learning task (fast-mapping task), the lexical tone perception task, the non-word repetition task, and the social-emotion questionnaires. At age four, Children with language delay were further classified into the language delay group (LD, n = 12) and the late bloomer group (LB, n = 20), based on their language performance. Three main results were found in this study. First, the LD group showed poorer language performance than the LB group at age two, at age three and at age four. In addition, the two groups manifested different language development trajectories from age two to four. Second, the LB group had better performance than the LD group in receptive language, word learning and lexical-tone perception when they were at age two. The results of the logistic regression analysis showed that two-year-old late-talkers with better performances in receptive language, word-learning, and lexical-tone perception had lower risk to be diagnosed as having language disorder at age four. Also, the results of the hierarchical linear models (HLM) revealed that two-year-old late talkers with better word learning ability and lexical-tone perception would showed faster growth rate in language abilities from age two to age four. Third, the LT children at age two already revealed more internalizing emotional problems, compared with the TD children. This trend was also observed when they reached age four. The LT children at age four performed poor adaptive behaviors in the VABS subscales of “Communication”, “Daily Living Skill”, and “Social”. Their performances in “Communication” and “Daily Living Skills” at age four were found to be predicted by their mother’s education level. The results showed that the late-talking children had revealed considerable individual differences in language abilities and social-emotional characteristics since age two, and the variation remained relatively stable at least until age four. The findings of this study may shed light on the early detection and early intervention of language development disorders in late-talking children.