Dyslexia has been around for a long time and has been defined in different ways. For example, in 1968, the World Federation of Neurologists defined dyslexia as “a disorder in children who, despite conventional classroom experience, fail to attain the language skills of reading, writing, and spelling commensurate with their intellectual abilities.” According to the U.S. National Institutes of Health, dyslexia is a learning disability that can hinder a person’s ability to read, write, spell, and sometimes speak. Dyslexia is the most common learning disability in children and persists throughout life. The severity of dyslexia can vary from mild to severe. The sooner dyslexia is treated, the more favorable the outcome; however, it is never too late for people with dyslexia to learn to improve their language skills.

Children with dyslexia have difficulty in learning to read despite traditional instruction, at least average intelligence, and an adequate opportunity to learn. It is caused by an impairment in the brain’s ability to translate images received from the eyes or ears into understandable language. It does not result from vision or hearing problems. It is not due to mental retardation, brain damage, or a lack of intelligence.

Dyslexia can go undetected in the early grades of schooling. The child can become frustrated by the difficulty in learning to read, and other problems can arise that disguise dyslexia. The child may show signs of depression and low self-esteem. Behavior problems at home as well as at school are frequently seen. The child may become unmotivated and develop a dislike for school. The child’s success in school may be jeopardized if the problem remains untreated.

讀寫障礙的發現已有一段時間,至今已發展出不同的定義。例如根據世界神經外科學會聯盟於1968年給出的定義,讀寫障礙是“一個出現於小朋友身上的徵狀,這些小朋友即使受到常規的學校教育,也難以習得與其智力相應的閱讀、寫作、拼寫等語言能力”。而根據美國國立衛生研究院的說法,讀寫障礙是一種學習障礙,它會窒礙人的閱讀、寫作、拼寫,甚至說話能力。讀寫障礙是最常見於小朋友身上的學習障礙,影響能持續一生。讀寫障礙的嚴重程度可分成中等至嚴重不等,愈早得到治療,效果愈好。不過,有讀寫障礙的人士如果想提升語言能力,任何時候都不會為時太晚。

即使有一般正常的智力,加上充足的學習機會,患有讀寫障礙的兒童在傳統指引下,會感到難以掌握閲讀技巧。這是由於腦部某些能力出現障礙,無法將從眼耳接收到的信息,轉換成可理解的語言。這與視力和聽力問題無關,也不是由智障、缺乏智力或腦部受損所造成。

在學童早期的學校教育中,讀寫障礙未必會被發現。 他們或會因為閱讀上出現的困難而感到沮喪,繼而衍生出其他問題,掩蓋了讀寫障礙。 孩子可能表現得抑鬱,自尊感低,於家中和學校常有行為問題,並缺乏動力,不喜歡上學。 如果問題持續未得到處理,可能會窒礙孩子學業上的發展。