Dyslexia has been woven in the fabric of society for centuries. Dyslexia often goes unnoticed, as the severity or effects of dyslexia are different for each individual. Some individuals are better at masking the effects than others. This has made defining dyslexia a challenge.
In my research of dyslexia, I stumbled upon Dr. James Hinshelwood, an optical surgeon who worked at the Glasgow Eye Infirmary in Scotland during the 1890s through the early 1920s. Some of his findings and definitions of word-blindness help to better understand the scope of the learning issue and why the definition has been hard to corral.
The following notes are from Hinshelwood’s (1917) research about individuals who struggle at learning how to read that were referred to the Glasgow Eye Infirmary or to an ophthalmologist for an examination. As a result, Hinshelwood discovered that one student could not read more than two or three words by sight. The student could only read if he or she was allowed to spell the words aloud one letter at a time or by moving his or her lips because the voiced word engaged the auditory memory, and the lip movement engaged speech or kinesthetic memory. Hinshelwood also examined several students with similar problems. For example, one student had healthy and normal vision, but he could not read any of the letters of the alphabet. However, he could recite the alphabet by memory. He could read a few words by spelling the words out letter by letter. When he viewed the same word a few sentences later, he did not recognize the word. The student had a good memory and excelled in his other subjects. Hinshelwood’s work at the Glasgow Eye Infirmary led to the discovery of word-blindness.
Hinshelwood (1917) believed that congenital word-blindness was difficult to fully comprehend and was often misdiagnosed. Hinshelwood noted that a German named Kussmaul determined that word blindness occurred when “complete text blindness may exist, although the power of sight, the intellect, and the powers of speech are intact” (p. 3). Hinshelwood also noted that word-blindness meant “a condition in which with normal vision and therefore seeing the letters and words distinctly, an individual is no longer able to interpret written or printed language” (p. 4). He believed that people could develop word-blindness as a result of family genetics or through injury. Hinshelwood focused on the genetic causes of word-blindness, which led to the following definitions.
Hinshelwood (1917) defined three different degrees of congenital word-blindness: (a) congenital word-blindness, (b) congenital dyslexia, and (c) congenital alexia. He defined congenital word-blindness as the “pure and grave cases of defect” (Hinshelwood, 1917, p. 70). Hinshelwood describes congenital dyslexia as a “slighter degrees of defect” (p. 70) or “great difficulty in interpreting written and printed symbols (Hinshelwood, 1900, p. 48). Professor Berlin of Stuttgart introduced the term dyslexia to describe a group of patients struggling to learn how to read, “due to the development of cerebral disease” (p. 60). Hinshelwood believed that congenital alexia was a defect in the visual memory center. The term congenital was noted to distinguish between natural and acquired.
Hinshelwood (1917) argued that each student diagnosed with word-blindness or dyslexia will have similar yet different characteristics and that diagnosis of students with word-blindness should begin in the regular education classroom. Teachers in these classrooms should refer those students who are struggling with learning to read to an eye doctor for a visual examination.
After years of research that produce multiple definitions of dyslexia the International Dyslexia Association (IDA) developed a Definition Consensus Project or a committee to corral the definition of dyslexia. On November 12, 2002, IDA adopted the following definition:
Dyslexia is a specific learning disability that is neurobiological in origin. It is characterized by difficulties with accurate and/or fluent word recognition and by poor spelling and decoding abilities. These difficulties typically result from a deficit in the phonological component of language that is often unexpected in relation to other cognitive abilities and the provision of effective classroom instruction. Secondary consequences may include problems in reading comprehension and reduced reading experience that can impede growth of vocabulary and background knowledge.
After many years of research there are valid methods of diagnosing dyslexia, but it can still elude diagnosis. I will discuss more about how to diagnose dyslexia in future posts.
References
Hinshelwood, James. (1900). Letter-, word- and mind-blindness. London: H. K. Lewis.
Hinshelwood, James. (1917). Congenital word-blindness. London: H. K. Lewis.
Definition of Dyslexia (2002). International Dyslexia Association, Retrieved from: https://dyslexiaida.org/definition-of-dyslexia/, July 11, 2018.
