Journal of Neurology, Neurosurgery, and Psychiatry, 1979, 42, 1115-1124
Phonological alexia: three dissociations M. F. BEAUVOIS AND J. DEROUESNE From Laboratoire de Neuropsychologie INSERM U.84, Hopital de la Salpetriere, Paris, France
Three dissociations were observed in a case of alexia: a disturbance of reading, without comparable disturbance of oral expression, oral comprehension, writing, or spelling aloud; a disturbance of the phonological reading process, without disturbance of the nonphonological reading process; a disturbance located at the level of the phonological stage, without disturbance of the perceptual and expressive stages. This pattern of results has been called phonological alexia. SUMMARY
Most research on alexia has until recently been or a psycholinguistic point of view. Three tendencies carried out from a syndromic and anatomoclinical can be distinguished among them. Some investigapoint of view. This has led to a broadly accepted tors have attempted to find facts confirming or classification of alexia in terms of the clinical invalidating particular aspects of a general theory symptoms which are usually found in conjunction of linguistic competence (Marshall and Newwith it. This classification conforms in essence combe, 1966). Others, on the basis of a method to that of Dejerine (1891) with three varieties of of linguistic analysis, have tried to describe readalexia being distinguished (Benson and Geschwind, ing disorders more systematically. For example, (1969): alexia with agraphia, aphasic alexia, and following Hecaen (1967) in applying the principles pure alexia (or alexia without either agraphia or of distributional analysis, Dubois-Charlier (1971, aphasia). Each variety of alexia is ascribed to a 1972) and Kremin (1976) proposed a classification distinct neuroanatomical locus of lesion in the left of alexia according to linguistic level-they discerebral hemisphere-alexia with agraphia is tinguished literal alexia, verbal alexia, and phrastic ascribed to a parietal lesion, aphasic alexia to a alexia. Finally, others have considered alexia as a temporo-parietal one, and pure alexia to a lesion of means of studying the production of reading bethe left occipital lobe, associated by many authors haviour itself in terms of the information processwith a lesion of the splenium of the corpus callo- ing systems involved (Marshall and Newcombe, sum. However, there are problems with this 1973; Shallice and Warrington, 1975; Patterson classification. Firstly, recently reported cases of and Marcel, 1977; Saffran and Marin, 1977). The alexia (Albert et al., 1973; Benson, 1977) cannot research reported here has been carried out from be included in any one of the three varieties. this last point of view. In this report we use a model of the reading Secondly, any one variety can be interpreted in several ways. For example, alexia without agraphia processes derived from an organigram proposed is thought of either as consecutive to a defect in by Andreewsky (1974) and related to certain visual perception (Alajouanine et al., 1960; hypotheses on reading behaviour suggested during Lhermitte and Gautier, 1969) or to a visuoverbal the previous few years (Albert et al., 1973; disconnection (Geschwind, 1965). Thus, this Marshall and Newcombe, 1973; Shallice and Warclassification can neither account for numerous rington, 1975; Patterson and Marcel, 1977;
reading impairments which result from cerebral lesions, nor permit distinction of reading disturbances caused by different dysfunctions in any one variety of alexia. For about 10 years, some studies on alexia have been carried out from a linguistic Address for correspondence and reprint requests: Dr M. F. Beauvois, Laboratoire de Neuropsychologie INSERM U.84, H6pital de la Salpetri6re, 47 Bd de l'H6pital, 75634 Paris Cedex 13, France. Accepted 12 May 1979
Schwartz et al., 1977; Saffran and Marin, 1977). In the model, reading is assumed to involve at least two processes which must be distinguished at the perceptuovisual level as well as at the linguistic level. The first reading process is analytical at the visual level and phonological at the linguistic level. The proposed sequence is as follows: first, there is an analytical, letter-by-letter or syllable-by-
1115
1116 syllable visual processing; then a linguistic correspondence between these visually identified letters and explicitly or implicitly uttered sounds is effected; the word can be understood only when this analytical processing is effected for all or almost all of its letters. Thus, at the linguistic level success in this reading process depends on a phonological stage (grapheme-phoneme correspondence) which precedes and conditions lexical and semantic stages. This is why this process is called phonological reading process. On the other hand, the second reading process is global at the visual level, and lexical or semantic at the linguistic level. The proposed sequence is as follows: at the visual level the different letters of a word are understood simultaneously and globally, and are recognised as a whole (or a subset of letters is understood and constitutes a clue which is sufficient to evoke the word); then a linguistic correspondence between this identified unit and a particular word is effected. At the linguistic level, success in this reading process depends first on a lexical or semantic stage which precedes and conditions the phonological stage, ie implicit verbalisation, so that the verbalisation of a word does not necessarily precede its comprehension; for Andreewski (1974) it is even probable that comprehension precedes verbalisation. Consequently, not all written stimuli can be read by means of this reading process; only lexical and meaningful ones can. This process is called lexical or non-phonological reading process. In the last few years several neuropsychological studies bearing on cases of a reading impairment which has been called either deep (Marshall and Newcombe, 1973) or phonemic (Shallice and Warrington, 1975) dyslexia have contained arguments for the existence of two reading processes. Two types of research have been done. Firstly, the description of this type of alexia made it possible to postulate the existence of a non-phonological reading route. Experimental research then established that patients with deep dyslexia did manifest impairment of the phonological reading route (Patterson and Marcel, 1977; Saffran and Marin, 1977), which showed that their performances were certainly linked to the existence of a nonphonological route. At the present time some problems remain. Firstly, these researches were all carried out on aphasic patients. Consequently, these patients' errors were not necessarily related to the supposed impairment. For example, the presence of semantic paraphasias in reading aloud may be caused by an impairment of stages located after the establishment of the grapheme-phoneme
M. F. Beauvois and J. Derouesne
correspondence (related to aphasia) and not by a patient's inability to establish this correspondence. Secondly, the level at which impairment of the phonological route is situated has not always been specified experimentally. Thirdly, the possible effects of the disturbance upon other linguistic tasks have never been studied. In this paper we report a neuropsychological study of a case of alexia without expressive or receptive dysphasia, which was carried out on the basis of the reading behaviour model previously described. The experiment was conducted to answer the following questions. 1. Can the two postulated reading processes work independently? In order to answer this, the question was asked whether serious but incomplete alexia could be due to a single reading process disturbance. 2. Was the reading process disturbed at the level of visual perception, verbalisation, or at the intermediate linguistic level? 3. Were other activities, which might have been assumed to involve the stage disturbed, normally performed by the patient?
Case summary As the detailed case report and its anatomical data have been reported by Beauvois et al. (1978), only a short summary is given here. The patient (RG) was a right handed, 64 year old man, a retired agricultural machinery representative. Two years before the neuropsychological study, he had been operated upon for a left parieto-occipital angioma. Computerised tomography scans showed a lesion involving the left angular gyrus, the posterior part of the second temporal convolution, the inferior longitudinal fasciculus, the geniculostriate fibres, and some fibres of the tapetum. At the time of this study, besides the alexia, he was still suffering from the following neurological defects: right inferior quadrantanopia, mild memory deficit, mild calculation impairment, mimimal constructional apraxia, and astereognosia. On the other hand, he suffered from neither motor nor sensory defect; his oral expression and comprehension could be considered to be good, with the exception of the bilateral tactile aphasia previously reported. The alexia was serious enough to prevent the patient from resuming his work, and had continued without any change for two years. While he had been a passionate reader, RG could no longer read a paper or a letter he had just written. The Alouette reading test (Lefavrais, 1963) confirmed his serious reading disability: his reading level was
Phonological alexia
that of a 6 year old child-that is, the level of the lowest class at primary school. This was due to very slow reading (in this text, RG could not read more than 62 stimuli in three minutes) and to the presence of numerous errors (40% of the stimuli were misread or not read at all) which involved particularly articles, possessive adjectives, conjunctions, and some verbs. In contrast with his very impaired reading, his writing was fairly good with the exception of some spelling mistakes. He could write down a message and draw up a text on a particular topic, being impeded only by the fact that he could not read over what he had written.
Neuropsychological study FUNCTIONAL INDEPENDENCE OF THE TWO READING PROCESSES
First procedure Each of the two reading processes was excluded successively at the perceptual level, by experimental procedures making impossible either analytical or global word perception. The patient was asked to read aloud two lists of nouns. In the first, the words were presented in handwritten form. The letters themselves were hardly recognisable, so that the word could be identified practically only from its global form. In the second, the word letters were very legible (they were capital letters in print form) but their order was reversed (for instance, BOUTEILLE was written ELLIETUOB) in order to prevent any global word recognition and to make an analytical perception necessary. Words were read aloud nearly perfectly by means of global perception (19/20); none was read aloud by means of analytical perception (0/20), although the patient was given several minutes to do so.
Second procedure The phonological reading process was handled at the linguistic level. When the stimuli are meaningful, the lexical reading process is sufficient, and the phonological reading process is unnecessary; but when the stimuli are meaningless, the phonological reading process becomes necessary. Thus, the reading of meaningless stimuli-that is, arbitrary strings of letters or digits-was compared with the reading of meaningful stimuli-that is, nouns or meaningful numbers. Test I Reading aloud of letter strings The subject had to read aloud a list of 40 nouns (each of five to nine letters) and a list of 40 non-words (each of four or five letters-for example, PUKO,
1117 DIRMA). All the nouns were read correctly, compared with only 10% of the non-words. Nouns were read quickly whereas non-words were read very slowly. Misreading of non-words resulted from either a failed attempt to decode analytically or an attempt to reconstitute the non-word from a word which looked like it (VINA: "c'est presque vinaigre", ie, "it's almost vinegar"; FOTA: "on dirait presque football", ie, "it looks like football"). Test 2 Reading aloud of numbers The subject was asked to read aloud two lists of 10 four-digit numbers. In the first, the numbers had no obvious meaning (for example, 4358); in the second, they were meaningful (for instance, the year of the patient's birth, the dates of the second world war). The patient was told that the numbers of the first list were meaningless and the numbers of the second meaningful. No meaningless number was read correctly; all meaningful numbers were correctly and quickly read. Test 3 Pointing out a letter string corresponding to an orally presented stimulus The patient was asked to designate from 20 letter strings, the one corresponding to a stimulus pronounced by the experimenter. He had to point out 40 nouns and 40 non-words consecutively. All the nouns were pointed out correctly, compared with only 30% of the non-words. Third procedure The variables affecting the necessarily phonological reading of non-words were researched and it was verified that they did not affect the reading of words, which was assumed to be achieved by the lexical reading process. Two variablesstimulus length and syllabic composition-were manipulated. Stimulus length The patient was asked to read aloud two lists of stimuli. The first list contained non-words: 40 single letters, 40 two-letter nonwords, and 40 four- or five-letter non-words. The second list contained nouns including 20 short ones (three letters) and 20 long ones (six to nine letters). The longer the non-words, the worse they were read (Table 1). There was no significant difference between reading performance for short and long nouns. Syllabic composition The order of vowels and consonants in a word could affect reading difficulty. Stimuli of simple syllabic composition-that is, in which each consonant is followed by one vowel (CVCV) might be easier to read than stimuli in which consonants were found in succession (CCVC). So, the effect of syllabic composition was studied in reading performance for
1118
M. F. Beauvois and J. Derouesne'
Table 1 Effect of stimulus length on reading performance. Percentage of correct responses Type of word Stimulus length
Non-word Noun
One letter 87% Three letters 85%
Two letters Four or five letters 42% 10% Six to nine letters 100%
words (nouns and adjectives) and non-words. The test on words was composed of two lists of stimuli. In the first list (20 words), the syllabic composition was assumed to be simple (for example, domino, securite). In the second one (40 words) the syllabic composition was assumed to be complex (for example, absolu, frustre). The two lists were equivalent as regards certain characteristics of their words- length, frequency, grammatical category. The test on non-words was composed of two lists of 40 stimuli. In the first, the syllabic composition was simple (for example, VORA). In the second, it was complex (for example, STO). The non-words having a simple syllabic composition were made up of four letters; the nonwords having a complex composition were made up of three letters. Syllabic composition significantly affected reading of non-words. It did not affect reading of words (Table 2). It is clear, both from the model proposed above, and from the results obtained in patients with deep dyslexia, that not all categories of words can be read aloud by means of the lexical reading process. From the model, the fact that words can or cannot be read by the global process would depend on their meaning (the words having little meaning would not be read), and the results obtained in patients with deep dyslexia are affected by variables such as frequency, concreteness, and parts of speech. Since the aim of this study was to show the opposition between the phonological and the non-phonological reading processes, and not to test the efficiency of the global process, all the words chosen for the tests described above were high frequency (20 per million; Gougenheim Table 2 Effect of syllabic composition on reading performance. Percentage of correct responses Simple
Complex
composition
composition
Non-words
eg: VORA
Words
55% eg: FACILrrTE
eg: STO 32% eg: FRUSTRE
75%
75%
S=significant; NS=not significant.
Comparison X2 test
X2=5.54,P
Phonological alexia: three dissociations M. F. BEAUVOIS AND J. DEROUESNE From Laboratoire de Neuropsychologie INSERM U.84, Hopital de la Salpetriere, Paris, France
Three dissociations were observed in a case of alexia: a disturbance of reading, without comparable disturbance of oral expression, oral comprehension, writing, or spelling aloud; a disturbance of the phonological reading process, without disturbance of the nonphonological reading process; a disturbance located at the level of the phonological stage, without disturbance of the perceptual and expressive stages. This pattern of results has been called phonological alexia. SUMMARY
Most research on alexia has until recently been or a psycholinguistic point of view. Three tendencies carried out from a syndromic and anatomoclinical can be distinguished among them. Some investigapoint of view. This has led to a broadly accepted tors have attempted to find facts confirming or classification of alexia in terms of the clinical invalidating particular aspects of a general theory symptoms which are usually found in conjunction of linguistic competence (Marshall and Newwith it. This classification conforms in essence combe, 1966). Others, on the basis of a method to that of Dejerine (1891) with three varieties of of linguistic analysis, have tried to describe readalexia being distinguished (Benson and Geschwind, ing disorders more systematically. For example, (1969): alexia with agraphia, aphasic alexia, and following Hecaen (1967) in applying the principles pure alexia (or alexia without either agraphia or of distributional analysis, Dubois-Charlier (1971, aphasia). Each variety of alexia is ascribed to a 1972) and Kremin (1976) proposed a classification distinct neuroanatomical locus of lesion in the left of alexia according to linguistic level-they discerebral hemisphere-alexia with agraphia is tinguished literal alexia, verbal alexia, and phrastic ascribed to a parietal lesion, aphasic alexia to a alexia. Finally, others have considered alexia as a temporo-parietal one, and pure alexia to a lesion of means of studying the production of reading bethe left occipital lobe, associated by many authors haviour itself in terms of the information processwith a lesion of the splenium of the corpus callo- ing systems involved (Marshall and Newcombe, sum. However, there are problems with this 1973; Shallice and Warrington, 1975; Patterson classification. Firstly, recently reported cases of and Marcel, 1977; Saffran and Marin, 1977). The alexia (Albert et al., 1973; Benson, 1977) cannot research reported here has been carried out from be included in any one of the three varieties. this last point of view. In this report we use a model of the reading Secondly, any one variety can be interpreted in several ways. For example, alexia without agraphia processes derived from an organigram proposed is thought of either as consecutive to a defect in by Andreewsky (1974) and related to certain visual perception (Alajouanine et al., 1960; hypotheses on reading behaviour suggested during Lhermitte and Gautier, 1969) or to a visuoverbal the previous few years (Albert et al., 1973; disconnection (Geschwind, 1965). Thus, this Marshall and Newcombe, 1973; Shallice and Warclassification can neither account for numerous rington, 1975; Patterson and Marcel, 1977;
reading impairments which result from cerebral lesions, nor permit distinction of reading disturbances caused by different dysfunctions in any one variety of alexia. For about 10 years, some studies on alexia have been carried out from a linguistic Address for correspondence and reprint requests: Dr M. F. Beauvois, Laboratoire de Neuropsychologie INSERM U.84, H6pital de la Salpetri6re, 47 Bd de l'H6pital, 75634 Paris Cedex 13, France. Accepted 12 May 1979
Schwartz et al., 1977; Saffran and Marin, 1977). In the model, reading is assumed to involve at least two processes which must be distinguished at the perceptuovisual level as well as at the linguistic level. The first reading process is analytical at the visual level and phonological at the linguistic level. The proposed sequence is as follows: first, there is an analytical, letter-by-letter or syllable-by-
1115
1116 syllable visual processing; then a linguistic correspondence between these visually identified letters and explicitly or implicitly uttered sounds is effected; the word can be understood only when this analytical processing is effected for all or almost all of its letters. Thus, at the linguistic level success in this reading process depends on a phonological stage (grapheme-phoneme correspondence) which precedes and conditions lexical and semantic stages. This is why this process is called phonological reading process. On the other hand, the second reading process is global at the visual level, and lexical or semantic at the linguistic level. The proposed sequence is as follows: at the visual level the different letters of a word are understood simultaneously and globally, and are recognised as a whole (or a subset of letters is understood and constitutes a clue which is sufficient to evoke the word); then a linguistic correspondence between this identified unit and a particular word is effected. At the linguistic level, success in this reading process depends first on a lexical or semantic stage which precedes and conditions the phonological stage, ie implicit verbalisation, so that the verbalisation of a word does not necessarily precede its comprehension; for Andreewski (1974) it is even probable that comprehension precedes verbalisation. Consequently, not all written stimuli can be read by means of this reading process; only lexical and meaningful ones can. This process is called lexical or non-phonological reading process. In the last few years several neuropsychological studies bearing on cases of a reading impairment which has been called either deep (Marshall and Newcombe, 1973) or phonemic (Shallice and Warrington, 1975) dyslexia have contained arguments for the existence of two reading processes. Two types of research have been done. Firstly, the description of this type of alexia made it possible to postulate the existence of a non-phonological reading route. Experimental research then established that patients with deep dyslexia did manifest impairment of the phonological reading route (Patterson and Marcel, 1977; Saffran and Marin, 1977), which showed that their performances were certainly linked to the existence of a nonphonological route. At the present time some problems remain. Firstly, these researches were all carried out on aphasic patients. Consequently, these patients' errors were not necessarily related to the supposed impairment. For example, the presence of semantic paraphasias in reading aloud may be caused by an impairment of stages located after the establishment of the grapheme-phoneme
M. F. Beauvois and J. Derouesne
correspondence (related to aphasia) and not by a patient's inability to establish this correspondence. Secondly, the level at which impairment of the phonological route is situated has not always been specified experimentally. Thirdly, the possible effects of the disturbance upon other linguistic tasks have never been studied. In this paper we report a neuropsychological study of a case of alexia without expressive or receptive dysphasia, which was carried out on the basis of the reading behaviour model previously described. The experiment was conducted to answer the following questions. 1. Can the two postulated reading processes work independently? In order to answer this, the question was asked whether serious but incomplete alexia could be due to a single reading process disturbance. 2. Was the reading process disturbed at the level of visual perception, verbalisation, or at the intermediate linguistic level? 3. Were other activities, which might have been assumed to involve the stage disturbed, normally performed by the patient?
Case summary As the detailed case report and its anatomical data have been reported by Beauvois et al. (1978), only a short summary is given here. The patient (RG) was a right handed, 64 year old man, a retired agricultural machinery representative. Two years before the neuropsychological study, he had been operated upon for a left parieto-occipital angioma. Computerised tomography scans showed a lesion involving the left angular gyrus, the posterior part of the second temporal convolution, the inferior longitudinal fasciculus, the geniculostriate fibres, and some fibres of the tapetum. At the time of this study, besides the alexia, he was still suffering from the following neurological defects: right inferior quadrantanopia, mild memory deficit, mild calculation impairment, mimimal constructional apraxia, and astereognosia. On the other hand, he suffered from neither motor nor sensory defect; his oral expression and comprehension could be considered to be good, with the exception of the bilateral tactile aphasia previously reported. The alexia was serious enough to prevent the patient from resuming his work, and had continued without any change for two years. While he had been a passionate reader, RG could no longer read a paper or a letter he had just written. The Alouette reading test (Lefavrais, 1963) confirmed his serious reading disability: his reading level was
Phonological alexia
that of a 6 year old child-that is, the level of the lowest class at primary school. This was due to very slow reading (in this text, RG could not read more than 62 stimuli in three minutes) and to the presence of numerous errors (40% of the stimuli were misread or not read at all) which involved particularly articles, possessive adjectives, conjunctions, and some verbs. In contrast with his very impaired reading, his writing was fairly good with the exception of some spelling mistakes. He could write down a message and draw up a text on a particular topic, being impeded only by the fact that he could not read over what he had written.
Neuropsychological study FUNCTIONAL INDEPENDENCE OF THE TWO READING PROCESSES
First procedure Each of the two reading processes was excluded successively at the perceptual level, by experimental procedures making impossible either analytical or global word perception. The patient was asked to read aloud two lists of nouns. In the first, the words were presented in handwritten form. The letters themselves were hardly recognisable, so that the word could be identified practically only from its global form. In the second, the word letters were very legible (they were capital letters in print form) but their order was reversed (for instance, BOUTEILLE was written ELLIETUOB) in order to prevent any global word recognition and to make an analytical perception necessary. Words were read aloud nearly perfectly by means of global perception (19/20); none was read aloud by means of analytical perception (0/20), although the patient was given several minutes to do so.
Second procedure The phonological reading process was handled at the linguistic level. When the stimuli are meaningful, the lexical reading process is sufficient, and the phonological reading process is unnecessary; but when the stimuli are meaningless, the phonological reading process becomes necessary. Thus, the reading of meaningless stimuli-that is, arbitrary strings of letters or digits-was compared with the reading of meaningful stimuli-that is, nouns or meaningful numbers. Test I Reading aloud of letter strings The subject had to read aloud a list of 40 nouns (each of five to nine letters) and a list of 40 non-words (each of four or five letters-for example, PUKO,
1117 DIRMA). All the nouns were read correctly, compared with only 10% of the non-words. Nouns were read quickly whereas non-words were read very slowly. Misreading of non-words resulted from either a failed attempt to decode analytically or an attempt to reconstitute the non-word from a word which looked like it (VINA: "c'est presque vinaigre", ie, "it's almost vinegar"; FOTA: "on dirait presque football", ie, "it looks like football"). Test 2 Reading aloud of numbers The subject was asked to read aloud two lists of 10 four-digit numbers. In the first, the numbers had no obvious meaning (for example, 4358); in the second, they were meaningful (for instance, the year of the patient's birth, the dates of the second world war). The patient was told that the numbers of the first list were meaningless and the numbers of the second meaningful. No meaningless number was read correctly; all meaningful numbers were correctly and quickly read. Test 3 Pointing out a letter string corresponding to an orally presented stimulus The patient was asked to designate from 20 letter strings, the one corresponding to a stimulus pronounced by the experimenter. He had to point out 40 nouns and 40 non-words consecutively. All the nouns were pointed out correctly, compared with only 30% of the non-words. Third procedure The variables affecting the necessarily phonological reading of non-words were researched and it was verified that they did not affect the reading of words, which was assumed to be achieved by the lexical reading process. Two variablesstimulus length and syllabic composition-were manipulated. Stimulus length The patient was asked to read aloud two lists of stimuli. The first list contained non-words: 40 single letters, 40 two-letter nonwords, and 40 four- or five-letter non-words. The second list contained nouns including 20 short ones (three letters) and 20 long ones (six to nine letters). The longer the non-words, the worse they were read (Table 1). There was no significant difference between reading performance for short and long nouns. Syllabic composition The order of vowels and consonants in a word could affect reading difficulty. Stimuli of simple syllabic composition-that is, in which each consonant is followed by one vowel (CVCV) might be easier to read than stimuli in which consonants were found in succession (CCVC). So, the effect of syllabic composition was studied in reading performance for
1118
M. F. Beauvois and J. Derouesne'
Table 1 Effect of stimulus length on reading performance. Percentage of correct responses Type of word Stimulus length
Non-word Noun
One letter 87% Three letters 85%
Two letters Four or five letters 42% 10% Six to nine letters 100%
words (nouns and adjectives) and non-words. The test on words was composed of two lists of stimuli. In the first list (20 words), the syllabic composition was assumed to be simple (for example, domino, securite). In the second one (40 words) the syllabic composition was assumed to be complex (for example, absolu, frustre). The two lists were equivalent as regards certain characteristics of their words- length, frequency, grammatical category. The test on non-words was composed of two lists of 40 stimuli. In the first, the syllabic composition was simple (for example, VORA). In the second, it was complex (for example, STO). The non-words having a simple syllabic composition were made up of four letters; the nonwords having a complex composition were made up of three letters. Syllabic composition significantly affected reading of non-words. It did not affect reading of words (Table 2). It is clear, both from the model proposed above, and from the results obtained in patients with deep dyslexia, that not all categories of words can be read aloud by means of the lexical reading process. From the model, the fact that words can or cannot be read by the global process would depend on their meaning (the words having little meaning would not be read), and the results obtained in patients with deep dyslexia are affected by variables such as frequency, concreteness, and parts of speech. Since the aim of this study was to show the opposition between the phonological and the non-phonological reading processes, and not to test the efficiency of the global process, all the words chosen for the tests described above were high frequency (20 per million; Gougenheim Table 2 Effect of syllabic composition on reading performance. Percentage of correct responses Simple
Complex
composition
composition
Non-words
eg: VORA
Words
55% eg: FACILrrTE
eg: STO 32% eg: FRUSTRE
75%
75%
S=significant; NS=not significant.
Comparison X2 test
X2=5.54,P
