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It was recognized at a relatively early stage of medical history that injury or disease of the brain in adult patients could cause a loss of a specific cognitive skill such as the ability to name objects or the ability to read. Indeed observations of this type were often employed as an argument in favor of localization of function in the brain. Thus specific anomia or "loss of memory for words" was clearly described in the 16th century and the syndrome of alexia without agraphia was identified in the 17th century. But neither physicians nor educators were as quick to recognize that children might also suffer from specific cognitive disabilities as a consequence of congenital or early acquired disease. It was only in 1853 that the Dublin otologist, William Wilde, published his observations on children who were "dumb, but not deaf," i.e., suffering from specific language disability. As we know, developmental dyslexia went unrecognized until the end of the 19th century when Morgan published his famous case report. As so often happens, once the attention of physicians was called to the condition, they immediately observed it in their practice and a steady stream of papers on dyslexia appeared in the English and German medical literature between 1900 and 1910. Somewhat later, clinical psychologists recognized dyslexia as a distinctive condition and attempted to relate its occurrence to more basic defects in visualization, auditory perception and associational processes. On the other hand, educators were less ready to accept the real existence of "congenital wordblindness" as a clinical entity.

Theories of dyslexia are characterized by the special emphasis they place on either linguistic or nonlinguistic factors as causes of reading disability. 1 This paper will discuss emerging evidence in favor of the linguistic interpretation of dyslexia. The works of linguistic philosophers, such as Ludwig Wittgenstein, who argue that our personal language reflects our experiences and percep tions of reality, lend support to a linguistic theory of dyslexia. Linguistic philosophers view language as the window through which we perceive meaning in our world (Engle 1970; Wittgenstein 1953, 1958, 1961a, 1961b). When symbols represent real events or thought, language is critical for interpretation. The underlying hypothesis for a linguistic theory of dyslexia is that, regardless of the nature of a child's learning handicap (e.g., perceptual, motor, or memory deficits), the specific problem will eventually manifest itself in language functioning and, as such a child approaches the task of reading, these cumulative verbal deficits will hamper his success in decoding and comprehension (Clinkert 1977). To understand the verbal deficit hypothesis, one must allow an extension of the ordinary definition of language to include the concept of semiotics. Semiotics expands the notion of conventional language to include signs and symbols,2 so that mathematics, for example, is a language with a specialized syntax and vocabulary.

Evidence of different syndromes of developmental dyslexia raises the question of the interaction between dyslexic types and patterns of cerebral dominance. Some of the proposed classifications of dyslexia, and most notably the one proposed by Boder (1971), strongly suggest that dyslexic subtypes, that can be identified clinically by reading-spelling patterns, may possess different or opposite cerebral dominance patterns. Thus, research of cerebral dominance in dyslexia (i.e., Orton’s hypothesis) should involve careful selection and classification of subjects. When this is done it can be shown that electrophysiological measures can identify cerebral-dominance abnormalities in at least one subtype of developmental dyslexia.

There is growing interest in differentiating developmental dyslexia,1 as a specific psychoneurological learning disorder, from nonspecific reading retardation. Such differentiation has immediate practical bearing since spe cific dyslexia calls for remedial reading techniques that are not required in the management of nonspecific reading disorders. Moreover, early diag nosis of developmental dyslexia is essential for successful remediation and to prevent school failure with concomitant loss of self-esteem. The need for practical direct diagnostic criteria that would facilitate the early identification of developmental dyslexia has come into the fore front. This need is felt especially by physicians and psychologists, who are often the first to be consulted about the child's inability to read. It is also recognized that the diagnosis cannot be relevant to the educator unless it has immediate implications for remediation. The objectives of this paper are: (1) to present a critical review of pre vailing diagnostic concepts of developmental dyslexia and (2) to briefly describe three atypical patterns of reading and spelling, revealed through

In this paper I shall attempt to describe what has been and is meant by the terms "dyslexia," "specific dyslexia" and "developmental dyslexia"; common terms, which have become confusing because authors have used them in so many different ways. I shall discuss a number of clinical syndromes involving serious difficulties in learning to read and write in apparently healthy children of average intelligence which have been described in the literature. Some relevant work concerned with difficulties in learning to read and write carried out in the Department of Child Life and Health in the University of Edinburgh will be described.

being done to help the SLD child or adult. With this in mind, I attempted early in 1973 to contact several European colleagues who were involved in the diagnosis and remediation of specific language disabilities, especially dyslexia. Many people made my experience stimulating and informative. Only limitations of space prevent my sharing with readers a wealth of detail con cerning the innovative and valuable procedures these people employ. Any one visit could easily be the subject of an entire paper. It is good to know that so much is going on among our European friends and colleagues in the interest of the children who, whatever their mother tongues, seem so much like our own.

Informative, stimulating, warm and friendly, esthetically delightful and laced with creature comforts might describe any trip to Europe—or to most other places, for that matter. My recent visit was all that, but was focused on dyslexia and most of my time was spent with people who are as deeply interested and as effectively involved in the problem as any of us who are here. Like us, they are eager to learn what their opposite numbers across the water and on their own continent are doing. In the New British Dyslexia Association, now forming as a union of several local groups, a communication network is developing; and there are Polish-Czech interchanges, and within-country connections. However, I found quite frequently some sense of isolation from "dyslexia-international," even where within a country there were contacts and conferences. This was paral leled by interested, enthusiastic reception of your emissary-ecumenical from the Orton Society. For today's talk I thought of apologizing for not bringing you a full grown statistical analysis, but I think you will be glad to be spared that. I have neither the time nor the necessary hard data and, besides, in seven weeks I could only skim off some delicious cream. If you know of a well-funded graduate student or two, well-informed in the language field (for our friends over there are thus sophisticated), I'll be glad to help work out a dissertation plan, for which my trip can serve as a pilot study. I have my eye on one such person, but there's room for more, perhaps on a collaborative project. My next thought was to give you a running account, even though I haven't had time yet to review my 15 tapes and edit properly the 400 or so slides, but I'm not allowed to keep you here long enough for such an account. Besides, The Ancient Mariner was never an acceptable model. These statistics, though, I do have. Not counting a couple of lecture groups, and the children in a score or more of classrooms, I saw individually on professional matters at least 112 of our colleagues (and often also their relatives and non-dyslexia-related friends). Most particularly, I bring you