Linguistics Encyclopedia.pdf

The linguistics encyclopedia 154
These observations range from the first reference to a dominant hemisphere of the
brain for language by Broca (1865), a French neurologist (see LANGUAGE
PATHOLOGY AND NEUROLINGUISTICS), to the first use of the term word
blindness by Kussmaul (1877), a German internist; the term ‘dyslexia’ was first used by
Professor Berlin of Stuttgart in 1887 as an alternative to ‘word blindness’. In 1892,
Professor Déjérine of Paris found that in the brains of stroke patients with attendant
dyslexia, the damage tended to be located in the posterior-temporal region in the left
cerebral hemisphere, where the parietal and occipital lobes meet. The specialists
mentioned above were in the main working with traumatized patients who suffered
disturbances of spoken and written language. However, from 1895, James Hinshelwood,
a Glasgow eye surgeon, published in The Lancet and The British Medical Journal a series
of articles describing a similar disorder, but not apparently caused by brain injury. He
described the phenomenon as
a constitutional defect occurring in children with otherwise normal and
undamaged brains, characterized by a disability in learning to read so
great that it is manifestly due to pathological conditions and where the
attempts to teach the child by ordinary methods have failed.
(Hinshelwood, 1917, p. 16)
Following upon Hinshelwood’s seminal work in this field, the notion of a developmental
dyslexia was accepted by a number of medical and psychological authorities. These
include the eminent American neurologist Samuel Orton, who, in 1937, described the
underlying features of dyslexia as difficulties in acquiring series and in looking ‘at
random’, associating the occurrence with unstable patterns of individual laterality. He
related such patterns to hemispheric control of functions, and referred to the problem as
one of ‘lacking cerebral dominance’. The neurological conception of dyslexia may be
summed up in Skydgaard’s brief definition (1942): ‘A primary constitutional reading
disability which may occur electively’, or at greater length in Critchley(1964, p. 5):
Within the heterogeneous community of poor readers, there exists a
specific syndrome wherein particular difficulty exists in learning the
conventional meaning of a verbal symbol and of associating the sound
with the symbol in appropriate fashion. Such cases are marked by their
gravity and purity. They are ‘grave’ in that the difficulty transcends the
more common backwardness in reading and the prognosis is more serious
unless some special steps are taken in educational therapy. They are ‘pure’
in that the victims are free from mental defect, serious primary neurotic
traits and all gross neurological deficits. This syndrome of developmental
dyslexia is of constitutional and not of environmental origin and is
often—perhaps even always—genetically determined. It is independent of
the factor of intelligence and consequently may appear in children of
normal IQ while standing out conspicuously in those who are in the above
average brackets. The syndrome occurs more often in boys. The difficulty
in learning to read is not due to peripheral visual anomalies but represents
a higher level defect—an asymbolia. As an asymbolia, the problem in