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Brain (1998), 121, 1721–1734 Writing disorders in Italian aphasic patients A multiple single-case study of dysgraphia in a language with shallow orthography Claudio Luzzatti,1,2 Marcella Laiacona,3 Nadia Allamano,3 Antonio De Tanti4 and Maria Grazia Inzaghi4 1Istituto di Psicologia della Facoltà Medica, Università degli Studi di Milano, 2Servizio di Logopedia, IRCCS Fondazione S. Maugeri, Centro Medico di Montescano, Pavia, 3Servizio di Neuropsicologia, Divisione di Neurologia, IRCCS Fondazione S. Maugeri, Centro Medico di Veruno, Novara, 4Unità di Neuropsicologia, Divisione di Medicina Riabilitativa, Ospedale Valduce, Costa Masnaga, Lecco, Italy Correspondence to: Claudio Luzzatti, Istituto di Psicologia della Facoltà Medica, Università degli Studi di Milano, Via Tommaso Pini 1, 20134 Milano, Italy. E-mail: [email protected] Summary We report results of a writing task given to 53 mildly to moderately aphasic Italian subjects. The task was designed to test the writing performance along the subword-level routine for the spelling of regular words and non-words, and along the lexical routine for the spelling of irregular words. The aim of the study was to identify the incidence of different dysgraphic subtypes in Italian, a language that is considered to have shallow orthography. Its spelling, however, is not completely free of ambiguity. A five-part writing task was used: (i) words with regular one-sound-to-one-grapheme conversion; (ii) words with regular syllabic conversion; (iii) words with ambiguous transcription; (iv) loan-words; and (v) nonwords. For regular words, the effects of word length and word frequency, and of the variables determining the complexity of the acoustic-to-phonological conversion (continuant versus plosive phones; consonant-vowel sequence versus doubled consonants or consonant clusters) were also considered. Patients’ performances were classified according to the presence of a dissociation between (i) regular words and non-words, (ii) regular words and words with unpredictable spellings, and (iii) one-to-one and syllabic conversions. The 53 aphasic patients span the whole spectrum of dysgraphic taxonomy. Thirty-nine patients, in particular, manifested a dissociated pattern of performance. Eighteen patients showed a prevalent surface dysgraphic pattern and seven a phonological one, while 11 patients showed a mixed pattern (i.e. a better performance for regular words than for ambiguous words or regular non-words). Three patients showed a specific deficit for regular syllabic conversion rules only. A high rate of ‘mixed dysgraphia’ suggests either a mutual interaction of the two impaired routines when regular words are written, or two separate functional lesions: one at the level of the auditory-tophonological conversion procedure, the other at the level of the orthographic output lexicon. Keywords: dysgraphia; aphasia; writing; stroke Introduction Over the past two decades cognitive psychologists have proposed increasingly complex models to describe the processes underlying the normal processing of written language. These models were originally formulated to describe the operations underlying word naming (Coltheart et al., 1980; Patterson et al., 1985) and were subsequently adapted to describe writing of words to dictation (Beauvois and Dérouesné, 1981; Shallice, 1981; Baxter and Warrington, 1985; Harris and Coltheart, 1986; Patterson, 1986). The models assume the need for at least two processing routes, © Oxford University Press 1998 a lexical routine by which words are processed as a whole, and a subword-level routine following orthographic-tophonological conversion rules in reading, and vice versa, phonological-to-orthographic conversion rules in writing. The need for at least two procedures was formulated for English to explain the capacity of a literate subject to read and write both irregular words and legal non-words (i.e. non-lexical but phonotactically plausible phonological strings). Two routines are assumed to be necessary for reading aloud and writing to dictation in English, given that English 1722 C. Luzzatti et al. is a language with a relatively irregular orthographic system. On account of this irregularity it is often impossible to deduce the spelling of a word from the sequence of sounds that make it up. The claim for two routines has also been argued on the basis of results from patients with cerebral lesions. Focal brain damage may cause writing disorders that appear to involve either routine selectively. Consequently, some patients make correct use of phonological-to-orthographic conversion rules when writing, but cannot access lexical knowledge, and therefore regularize the spelling of irregular words. Such a deficit is generally called ‘surface dysgraphia’. Other patients can write words they have learned to spell in the past, whether these be regular or irregular, but are not able to write a legal non-word. Such a disturbance is generally called ‘phonological dysgraphia’. [N.B. We did not consider the possible further fractionating of the lexical routine into a semantic lexical and a direct phonological/orthographic lexical routine in this study. Consequently, the possibility of a writing deficit corresponding to the isolated impairment of these subroutines (direct dysgraphia) could not be tested.] Not all languages with an alphabetical system of writing are irregular like English. Some languages, such as SerboCroatian, are almost totally predictable, with regard to both reading and writing. Others may be relatively regular in one direction but not in the other; this is the case with French and German, the writing of which is very often unpredictable but reading aloud is relatively predictable. Italian is said to be a language with a shallow orthography, where the subwordlevel routine is sufficient for the great majority of words to be written. The phonological-to-orthographic conversion rules are simple with a one-to-one correspondence between sound and letter for all vowels and most consonants. As is the case with the majority of European languages, some Italian phones do not correspond to a single letter of the alphabet. The transcription of these phones is generally achieved by two or more letters. Typical examples are the phones [Q] (5 TH of English), [X] (5 CH of German), or the different spelling of [S] in Italian (SC6I), French (CH), English (SH) and German (SCH). The most typical Italian phones without a one-to-one correspondence are [ˆ] and [¥]; these are conveyed by the letter-pairs GN and GL, respectively. Slightly different is the realization of the velar versus palatal pairs [k] – [tS] and [g] – [dJ]. In the first case the rule is relatively simple—one must convert a phoneme with several letters instead of one. In the second case a syllabic conversion is required, i.e. the orthographic realization of a phone is determined by the vowel that follows it ([ka], [ko], [ku] 5 CA, CO, CU; [ki], [ke] 5 CHI, CHE; [tSa], [tSo], [tSu] 5 CIA, CIO, CIU; and [tSi], [tSe] 5 CI, CE). Finally, there are also conditions in Italian that are unpredictable both in written-to-oral and oral-to-written direction. Ambiguities in reading concern the site of stress in words of three or more syllables (GONDOLA (5 gondola) is pronounced [9gondola] and not *[gon9dola], whereas MENTOLO (5 menthol) is stressed [men9toló] and not *[9mentoló]). On the other hand, there are some conditions in which a given phonological string has more than one possible orthographic solution, though only one is correct for a certain lexeme; ambiguities in writing often have an etymological basis, and may apply to the pronunciation of some linguistic areas only. (i) The syllable [Se], for instance, is regularly transcribed by the sequence SCE. However, there are some words in which it is conveyed by the sequence SCIE, e.g. [Sentsa] 5 SCIENZA (5 science). The same applies to the syllables [tSe] and [dJe] which in certain cases are transcribed by the sequence CIE and GIE (CIELO (5 sky) instead of CELO, IGIENE (5 hygiene) instead of IGENE). (ii) The phonemic group [kw] may be transcribed by the orthographic sequences QU, CU, CQU. The general rule is that the syllables [kwa], [kwi] and [kwe] are transcribed with the sequences QUA, QUI and QUE, e.g. QUALE (5 which), QUINDI (5 thus), QUESTO (5 this), while the syllable [kwo] is transcribed by the sequence CUO [CUOCO (5 the cook)]. However, exceptions exist here too, e.g. QUOTA (5 the quota). (iii) The segments [¥] – [lj] and [ˆ] – [nj] which are phonologically distinct in Tuscan and central-southern pronunciation, are homophones in north-western Italian, so much so that the spelling of words like balia [ba¥a]/[balja], nurse (BALIA and not BAGLIA) or geranio [dJeraˆo]/[dJeranjo], the geranium (GERANIO and not GERAGNO) is not predictable along the phonological-to-orthographic conversion routine. (iv) Plosive phones that are followed by the liquid consonants ([l] and [r] or by the semiconsonant [j] are homophones to their doubled pairs, thus rendering uncertain the transcription of words such as [libro], book (LIBRO and not LIBBRO), [febre], fever (FEBBRE and not FEBRE), [biblico], biblical (BIBLICO and not BIBBLICO) and [publico], public, (PUBBLICO and not PUBLICO). (v) Finally, mention should be made of the spelling of ‘loan-words’ (usually from English or French) incorporated into the Italian lexicon (e.g. BLUE-JEANS, WEEK END, etc.). A correct use of the subword-level routine (i.e. of the phonological-to-orthographic conversion rules) requires that the subject first segments and identifies the phonemic string to be converted. Such analysis seems to be adequately represented by the information processing models in the acoustic-to-phonological conversion. This is the routine described by Wernicke (1885, 1886), who considered the processing of written language as exclusively segmental, as opposed to a purely lexical routine for the processing of oral language (De Bleser and Luzzatti, 1989). An acoustic-to-phonological level of analysis obviously depends on variables determining the complexity of this processing, such as the presence of consonant clusters, or the phonetic characteristics of the sounds themselves. Continuous phones, such as vowels, fricative consonants ([f], [v], [s], [z] and [S]), liquid ([l] and ([n]), and nasal ([n] and [m]) consonants that may be prolonged during the analysis, are by their nature more easily segmentable and hence Diagnosis of writing disorders identifiable, as it is possible to analyse their audio-phonetic (and stato-kinaesthetic) aspects at greater length. In order to evaluate the variables individually, described so far, a test battery was designed for the examination of writing disturbances in adult brain-damaged subjects. Certain phonetic/phonological variables generally overlooked in psycholinguistic studies were added to the variables generally considered in normal test batteries for writing deficits (length of stimulus, lexical/non-lexical material, word frequency). Material and methods Subjects Fifty-three mildly to moderately aphasic patients (30 males and 23 females) examined at the Aphasia Units of RhoPassirana (Milano), Veruno (Novara) and Costa Masnaga (Lecco) from 1993 to 1994 were included in the study. Their mean (6 SD) age was 41.9 6 17.9 years and education 10.8 6 2.5 years; their mean length of illness was 13.2 6 18.3 months. Forty patients suffered from vascular cerebral damage, 11 from traumatic brain injury and two from other aetiologies. Type and severity of aphasia was assessed by means of the Italian version of the Aachen Aphasia Test (Luzzatti et al., 1994a): 14 patients were classified as Broca’s aphasics, 21 had a fluent language disorder (11 Wernicke’s, six anomic and four non-classifiable aphasic patients). Eight patients could not be classified for the fluent/non-fluent dimension, whereas 10 showed only minimal residual language deficits. The control group included 110 healthy adults (49 males and 61 females). Their mean age was 44.2 6 15.1 years. Only subjects with ù8 years of schooling were included in order to be assured of a complete acquisition of written language (mean education 13.1 6 3.7 years). Subjects gave informed consent to participate in the study, which had ethical approval from the S. Maugeni Foundation. The test The writing test used in this study is described fully in Luzzatti et al. (1994b). It comprises the following five sections. Section A uses regular words with complete one-soundto-one-letter correspondence. Section B uses regular words with syllabic conversion (e.g. [k], [g], [tS], [dJ]). The spelling of sounds [¥], [ˆ], and syllables [tSe], [dJe] and [Se] which have two possible orthographic solutions (see next point) was not taken into account in this section. Section C uses words with unpredictable transcription along the phonological-to-orthographic conversion routine (e.g. [¥] in [pa¥a], straw: PAGLIA and not PALIA; [ba¥a], nurse: BALIA and not BAGLIA, or [ˆ] in [dJeˆo], genius: GENIO and not GEGNO; [seˆo], sign: SEGNO and not SENIO). Section D uses loan-words: foreign words which may by now be considered as part of the Italian lexicon (e.g. bluejeans, night-club). 1723 Section E uses non-words with one-sound-to-one-letter correspondence. As the experimental subjects were natives of Lombardy and Piedmont, in addition to the ambiguities which are common to all Italian speaking areas (e.g. the spelling of the syllable [kwo] or the single/doubled orthographic pair in a plosive followed by a liquid consonant), some of the ambiguities which are typical of the north-western Italian pronunciation were included. Moreover, in order to evaluate different sources of phonetic-phonological complexity, within Section A the following comparisons were made: (i) words made up only of continuant sounds (fricative, liquid or nasal consonants) with words also containing non-continuant (plosive) consonants; (ii) words made up only of consonant-vowel (CV) syllables with words also containing clusters or doubled consonants; (iii) bisyllabic with polysyllabic words. Each part of Section A used five high-frequency and five lowfrequency words (Bortolini et al., 1972). Table 1 summarizes the different sections of the writing task (see Appendix for the complete list of stimuli). The mean word frequency for each section is shown in Table 2. Regular words and words with unpredictable transcription have a very similar frequency, whereas loanwords are less frequent. The mean word frequencies of the five high-frequency and five low-frequency items for Section A (regular words with complete one-sound-to-one-letter correspondence) are also shown. Items are almost exclusively nouns; therefore the task does not enable us to detect word class differences. Furthermore, the task does not consider any lexical-semantic variables (such as the abstract/concrete dimension) that have been shown to influence the performance along the lexical routine (Bub and Kertesz, 1982; see also Shallice, 1988, pp. 138–142). Words and non-words were presented separately. The 158 words were randomized for regularity, complexity, word frequency and length, the 25 non-words for complexity and length. The examiner read each item aloud in a neutral tone, i.e. without emphasizing the presence of clusters, doubled consonants or possible orthographic ambiguities. Each item could be repeated once on request. No feedback was provided on the adequacy of the responses. Spontaneous corrections were accepted. Analyses of the results and statistical methods All the patients participating in the study suffered from a left hemisphere lesion causing mild-to-moderate language disorders and/or dysgraphia, but none showed a pure writing disorder. The principal purpose of our investigation was to detect the presence of significant differences between the ability to spell regular words, words with unpredictable transcription and non-words separately. The diagnostic criteria for different types of dysgraphia concern the dissociated (independent) impairment of performance with these different sets of stimuli. Since the majority of the patients showed 1724 C. Luzzatti et al. Table 1 Subtests of the writing task A Regular words with one-sound to one-letter correspondence (n 5 80) Examples 1 2 3 4 5 6 7 8 sole lavoro senso valle dito prato tappo sponda (Translation) Continuance Clusters Doubled consonants Syllables n (sun) (work) (sense) (valley) (finger) (meadow) (cork) (bank) Yes Yes Yes Yes No No No No No No Yes No No Yes No Yes (32) No No No Yes No No Yes No 2 3/4 2 2 2 2 2 2 10 10 10 10 10 10 10 10 B Regular words (syllabic conversion rules) (n 5 15) Example Rule n 9 [k], [g], [sk]; [tS], [dJ], [S] 15 gola/ghiro/valigia (throat/dormouse/suitcase) C Words with unpredictable transcription (n 5 55) Examples (translation) Ambiguity n 10 11 12 13 14 (scene/science) (straw/nurse) (sign/genius) (book/fever) (heart/quote/eagle) [tS], [S] : 6 I [¥] : GL/LI [ˆ] : GN/NI BR/BBR [kw] : CU/QU 10 10 10 10 15 scena/scienza paglia/balia segno/genio libro/febbre cuore/quota/aquila D Loan-words (n 5 8) Examples n 15 8 blue-jeans, night-club E Non-words with one-sound-to-one-letter correspondence (n 5 25) Examples Continuance Doubled consonants Syllables n 1 2 4 4 5 Yes Yes Yes No No No No Yes No Yes 2 3/4 2 2 2 5 5 5 5 5 nise vimàne/ramàsola seffa tido nitta Table 2 Word frequencies in the different tasks Stimulus Word frequency (mean 6 SD) Regular words (one-sound-to-one-letter correspondence) high frequency items low frequency items 47.39 6 69.57 91.25 6 76.42 3.52 6 4.33 Regular words (syllabic conversion) 31.47 6 40.53 Words with unpredictable transcription 47.55 6 96.49 Loan-words (,2) Total 43.53 6 76.86 Diagnosis of writing disorders 1725 Table 3 Performance of patients and control subjects on the five sections of the writing task (mean 6 SD) Section Control subjects (n 5 110) All aphasic patients (n 5 53) Broca’s aphasia (n 5 14) Wernicke’s aphasia (n 5 11) Anomic aphasia (n 5 6) Residual language deficits (n 5 10) A. Regular words with one-sound-to-oneletter correspondence (n 5 80) B. Regular words with syllabic conversion (n 5 15) C. Words with unpredictable transcription (n 5 55) D. Loan-words (n 5 8) E. Non-words (n 5 25) 79.8 6 0.6 61.8 6 19.0 54.9 6 15.8 50.6 6 28.7 73.2 6 8.8 76.6 6 3.1 15.0 6 0.2 9.9 6 4.1 8.1 6 3.7 8.2 6 5.3 11.8 6 1.9 13.4 6 1.7 52.5 6 2.2 29.2 6 13.6 23.1 6 13.2 22.8 6 13.7 35.3 6 12.9 42.3 6 7.5 5.9 6 2.5 24.7 6 0.6 1.2 6 1.8 14.6 6 8.1 0.6 6 1.2 10.5 6 7.5 0.3 6 0.7 13.1 6 8.8 2.0 6 2.1 17.7 6 5.1 2.4 6 2.6 22.4 6 2.4 mild-to-moderate language disorders, only a few patients showed a classical (strong) dissociation between a completely spared and a damaged writing routine. In fact, the dissociations shown by our patients are usually of the weak type, i.e. there is usually poor performance on both routines, though one routine is significantly more impaired. Logistic regression analysis (McCullagh and Nelder, 1983) was applied to the profile of each single subject, making it possible to study the effects of the variables that might have influenced performance within a linear model. The units were the stimuli of the Test and the dependent variable for each stimulus was two-valued (passed 5 1, failed 5 0). The model included both categorical (e.g. words versus nonwords) and continuous variables (word frequency and item difficulty). Difficulty (for each single item) is expressed as the number of control subjects (out of 110) who wrote it correctly. Each patient was classified into one of the major dysgraphic patterns through several comparisons. First, the four major sections of the task were checked for an overall performance homogeneity. Then, the following comparisons were made: (i) words with one-sound-to-oneletter correspondence and non-words with comparable phonological and orthographic complexity; (ii) words with unpredictable transcription and words with one-soundto-one-letter correspondence; and (iii) words with syllabic conversion and words with one-sound-to-one-letter correspondence. The eight loan-words were not considered in the logistic regression analyses as they constitute a separate and very limited set of items. Furthermore, the influence of the different sources of complexity included in the test, such as continuance, stimulus length and the presence of consonant clusters, was evaluated. Comparisons were programmed as a macro-instruction of the Generalized Linear Model program of Aitkin et al. (1989) (GLIM 3.77). The analysis was repeated for each of the 53 patients. As a single-case diagnostic procedure was used, the significance level of each comparison was set at 0.05, without adopting an overall protection for the whole set of patients (Willmes, 1985). The psychometric design also included covariance by item difficulty. Any dissociation still present after this adjustment will be stronger than—and not simply proportional to—the difference observed among control subjects. On the contrary, any dissociation which disappears after adjustment simply reflects the difficulty gradient observed in the normal control group. Results Control subjects The mean scores of the 110 control subjects on the five sections of the test, and on the eight parts of Section A (writing of regular words with one-sound-to-one-letter correspondence), are shown in Tables 3 and 4. Normal subjects wrote almost all items of the task flawlessly. However, this was not the case for the loan-word section, where control subjects registered a lower mean performance and a high degree of variability (5.9 6 2.5). An analysis of the performance of the control subjects was reported in detail in a previous paper (Luzzatti et al., 1994b). Education significantly influences the spelling of words with unpredictable orthography, age influences that of non-words, and both education and age influence that of loan-words. None of these variables, however, significantly influenced the subjects’ performances when they were writing regular words. An error analysis also revealed that the misspellings of the control subjects corresponded to those predicted for the different parts of the writing task. Normal subjects made a very low number of errors when writing regular words and non-words [for instance, when writing regular words they only made 12 errors out of 8800 written words]. The analysis was therefore made only for words with unpredictable transcription and for loan-words. Out of 6050 words containing a phone with an unpredictable transcription, control subjects made 435 errors; 378 of these were of the expected type (use of the subword-level routine instead of the lexical one, and therefore substitution of the target with a plausible but incorrect solution). When writing loan-words, control subjects produced 272 errors out of 880 written words; again, 94% of the misspellings were surface errors. Aphasic patients Table 3 also shows the mean performances obtained on the five sections by the 53 aphasic patients and by the 31 1726 C. Luzzatti et al. Fig. 1 The five sections of the writing test: score profiles (mean percentages) from control subjects and the aphasic patients who could be classified into one of the major aphasic syndromes. Table 4 Performance on the eight parts of Section A (regular words with one-sound-to-one-letter correspondences)* Section A (parts 1–8) 1 2 3 4 5 6 7 8 (e.g. (e.g. (e.g. (e.g. (e.g. (e.g. (e.g. (e.g. Control subjects (n 5 110) sole, sun) lavoro, work) senso, sense) valle, valley) dito, finger) prato, meadow) tappo, cork) sponda, bank) 9.97 9.97 9.95 9.97 9.97 10.00 9.97 9.99 6 6 6 6 6 6 6 6 0.2 0.2 0.3 0.2 0.2 0.0 0.2 0.1 All aphasic patients (n 5 53) 8.6 6.9 7.4 8.2 7.9 7.7 8.5 6.6 6 6 6 6 6 6 6 6 2.3 3.3 3.0 2.4 2.6 2.7 2.3 3.1 Broca’s aphasia (n 5 14) 8.0 5.9 6.2 7.4 7.6 6.8 8.1 4.9 6 6 6 6 6 6 6 6 2.5 3.1 2.6 2.3 2.4 2.7 1.8 3.1 Wernicke’s aphasia (n 5 11) 8.2 5.3 5.9 6.7 6.5 5.9 6.9 5.5 6 6 6 6 6 6 6 6 3.3 4.3 4.4 3.6 3.6 3.7 3.8 3.9 Anomic aphasia (n 5 6) 9.7 9.0 9.5 9.3 8.8 9.2 9.3 8.3 6 6 6 6 6 6 6 6 0.8 1.1 0.8 1.0 1.6 1.3 0.8 2.3 Residual language deficits (n 5 10) 9.8 9.3 9.4 9.6 9.9 9.5 9.8 9.3 6 6 6 6 6 6 6 6 0.4 0.8 0.8 0.7 0.3 0.7 0.4 1.1 Data are shown as means 6 SD. *See Table 1, Section A for the eight types of words. patients whose quantitative and qualitative performances corresponded to that of a classic Broca’s (n 5 14), Wernicke’s (n 5 11) and anomic (n 5 6) aphasia. Table 4 shows the mean performance on the eight parts of Section A (writing of regular words with one-sound-to-oneletter correspondence) for all patient groups. The mean (percentage) score profiles of control subjects and of the 31 patients that could be grouped according to the major aphasic syndromes are shown in Figs 1 and 2. Profiles of each individual subject were analysed by means of a logistic regression analysis. Due to the high variability shown by control subjects with loan-words, the patients’ performances in Section D were not considered in the regression analysis. The results are given in Table 5 and summarized in Table 6. Eighteen patients (34%) showed predominantly a writing impairment for words with unpredictable spelling, i.e. widespread damage to the lexical routine (surface dysgraphia), while seven patients (13%) showed an impairment for nonwords, i.e. mainly damage to the subword-level routine (phonological dysgraphia). Of the 18 surface dysgraphic patients, only four (MI02, VE08, CM04 and VE12) showed selective impairment of the lexical route and normal performance with non-words, while only one of the seven phonological dysgraphic patients (VE07) showed a selective impairment of non-words (subword-level routine) and normal spelling of regular words and of words with unpredictable spelling. Furthermore, 11 subjects (21%) showed a peculiar pattern of damage, characterized by an impaired writing performance for both words with unpredictable transcription and non-words, while they performed better on regular words with complete one-sound-to-one-letter correspondence. The Diagnosis of writing disorders 1727 Fig. 2 The eight parts of Section A of the writing test (regular words with one-sound-to-one-letter correspondence): score profiles from control subjects and aphasic patients that could be classified into one of the major aphasic syndromes. term ‘mixed dysgraphia’ will be used to designate the pattern of disruption observed in this group of patients. Three patients (6%) used the one-phoneme-to-one-letter conversion flawlessly but had trouble with syllabic conversion rules. Thirteen patients (25%) presented an undifferentiated writing deficit on all tasks, whereas one patient (2%) had no writing disorders. The analysis within the 80 items of Section A showed that four patients (8%) performed better on words composed exclusively of continuant phones (and thus more easily analysable by the auditory-to-phonological conversion unit) than on words also containing plosive consonants. Furthermore, nine patients (17%) showed a length effect, and the performance of four patients (8%) was influenced by the presence of consonant clusters. Half of the patients (24 out of 53) showed a word-frequency effect. The rate of patients showing a word-frequency effect varied across type of dysgraphia: six out of the seven patients with a phonological dysgraphia (86%), two of the three patients with a pure syllabic conversion deficit (67%), eight of the 18 patients with a surface dysgraphia (44%), six of the 11 patients with a mixed dysgraphia (55%) and two of the 13 patients with undifferentiated writing disorder showed a word-frequency effect; the patient with no dysgraphia did not show a word-frequency effect. A comparison of the rate of cases showing a word-frequency effect evidenced a different distribution between the phonological (6/7) and surface (8/18) dysgraphic patients (Fisher’s exact test (1), P , 0.05). Finally, semantic substitutions were limited to only two patients, and even in these two cases they were few [e.g. CM07: night-club→playboy; weekend→week-fine (Italian translation of ’end’); VE02: babbó→papa9 (father→dad); bació→abbració (kiss→hug)]. In both cases the phonologicalto-orthographic conversion routine was severely impaired. However, these patients showed a different degree of damage when writing words with unpredictable spelling. The first patient (VE02) could still write the majority of these words, and was therefore classified as a case of phonological dysgraphia, whereas the second patient (CM07) had a more conspicuous deficit of ambiguous words and was therefore classified as a case of mixed dysgraphia, still showing, however, a clear dissociation between ambiguous words and non-words (42% versus 0%). Table 6 also shows the distribution of dysgraphic disorders according to the classic aphasia taxonomy. Types of dysgraphia are similarly distributed along aphasic syndromes [χ2(25) 5 15.04, not significant]. Table 7 shows the distribution of patients with dysgraphic disorders according to aetiology. All seven of the phonological dysgraphic patients were found within the vascular group, while surface dysgraphia is proportionally more frequent among patients suffering from traumatic head injury. This difference, however, does not reach significance [χ2(5) 5 7.088, not significant]. Discussion The purpose of the present study was to verify the diagnostic validity of a writing task and the use of logistic regression analysis in a psychometric single case analysis. The writing task was administered to a sample of mildly to moderately aphasic Italian patients. The performances of the patients were compared to those of 110 control subjects (Luzzatti et al., 1994b). 1728 C. Luzzatti et al. Table 5 Classification of individual patients with multiple single-case analysis (logistic regression analysis) Case Words with one-sound to one-letter correspondences versus: Other significant effects: non-words continuancy length consonant clusters word frequency . . . . . . . . . 1 . 1 . 1 . . . . . . 1 1 1 1 1 . 1 χ2 P-value words with unpredictable transcription words with syllabic conversion χ2 χ2 Phonological dysgraphia CM09 6.524 0.011 0.065 CM18 15.292 ,0.0001 0.005 MI08 6.622 0.010 1.619 VE02 29.898 ,0.0001 0.429 VE04 14.329 0.0001 0.558 VE07 4.984 0.026 0.132 VE18 8.479 0.004 0.034 Deficit of syllabic conversion only CM08 0.961 1.567 CM10 1.224 0.269 3.302 MI14 0.189 0.650 Surface dysgraphia MI07 0.883 16.680 CM05 3.129 0.077 8.624 MI02 0.585 15.358 MI12 0.154 11.043 MI15 0.635 12.607 VE08 0 48.720 MI06 0.285 8.741 CM02 0.045 21.272 CM03 0.480 21.683 CM04 0.975 9.490 VE12 0 8.729 MI03 0.065 9.194 MI04 0.439 5.333 CM16 1.235 0.266 5.083 MI10 3.741 0.053 11.174 VE06 1.282 10.720 VE13 1.608 0.205 10.060 VE16 0.373 9.467 Mixed (phonological and surface) dysgraphia VE03 10.682 0.001 4.932 CM06 14.675 0.0001 5.201 CM07 33.764 ,0.0001 8.290 CM12 12.451 0.0004 7.793 CM19 7.326 0.007 12.095 MI09 11.652 0.0006 6.082 MI11 11.395 0.0007 17.841 VE01 5.150 0.023 27.595 VE10 4.563 0.033 6.985 VE11 6.174 0.013 13.591 VE15 16.264 ,0.0001 4.281 Undifferentiated writing disorders CM01 2.092 0.148 CM11 1.017 0.313 CM13 2.035 0.154 CM14 0.831 CM15 0.050 CM17 0.055 MI05 0.775 MI13 0.200 MI16 2.888 0.089 VE05 3.002 0.083 VE09 0.002 VE14 0.015 VE17 1.791 0.181 3.430 2.039 0.670 3.668 1.827 0.389 2.302 1.212 0.041 2.005 1.957 2.739 1.897 No dysgraphia MI01 0.164 0.136 P-value P-value 1.299 1.491 1.291 1.265 0.215 2.961 0.988 0.254 0.222 0.256 0.261 0.211 0.069 4.937 6.198 5.555 0.026 0.013 0.018 . . . . . 1 . . . 1 1 . ,0.0001 0.003 ,0.0001 0.0009 0.0004 ,0.0001 0.003 ,0.0001 ,0.0001 0.002 0.003 0.002 0.021 0.024 0.0009 0.001 0.002 0.002 10.999 6.716 5.576 8.830 5.564 8.734 2.423 1.801 1.828 2.944 0 0.122 0.005 0.761 0.464 0.246 0.271 0.549 0.0009 0.010 0.018 0.003 0.018 0.003 0.120 0.180 0.176 0.086 . . 1 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . . 1 1 . 1 . . . . 1 . 1 . 1 . 1 . 1 0.026 0.023 0.004 0.005 0.0005 0.014 ,0.0001 ,0.0001 0.008 0.0002 0.039 3.899 3.100 0.003 1.769 2.167 0.328 0.849 1.509 2.677 0.179 0.987 0.048 0.078 1 . . . . . . . . 1 . . . 1 . . . . . 1 . . 1 . 1 . . . . . . . . . 1 1 1 . 1 1 . . . 1 0.064 0.153 0.059 3.740 1.219 3.644 0.164 2.408 0.290 0.014 0.108 1.366 0.051 0.656 2.889 . . . . . . . . . . . . . . . 1 . . . 1 1 . . . . . . . . . . . 1 . . . . . . . 1 . . . . . . . 1 . . . . . . . 0.203 0.512 0.055 0.176 0.129 0.271 0.157 0.162 0.098 0.168 χ2 and P-values in bold reflect significant effects. 0.007 0.085 0.184 0.141 0.219 0.102 0.053 0.270 0.056 0.121 0.243 0.089 Diagnosis of writing disorders 1729 Table 6 Type of dysgraphia by type of aphasia: distribution across the 53 aphasic patients Broca’s aphasia (n 5 14) Wernicke’s aphasia (n 5 11) Anomic aphasia (n 5 6) Fluent aphasia (non-classifiable: Wernicke’s versus anomic) (n 5 4) Residual language deficits (n 5 10) Non-classifiable (fluent versus non-fluent aphasia) (n 5 8) All patients (n 5 53) Phonological dysgraphia 3 2 1 – – 1 7 Deficit of syllabic conversion – 1 – 1 1 – 3 Surface dysgraphia 5 3 3 1 4 2 18 Mixed dysgraphia 3 (phonological and surface) 2 1 1 1 3 11 Undifferentiated writing disorders 3 3 1 1 3 2 13 No dysgraphia – – – – 1 – 1 Table 7 Type of dysgraphia by aetiology: distribution across the 53 aphasic patients Phonological dysgraphia Deficit of syllabic conversion Surface dysgraphia Mixed dysgraphia (phonological and surface) Undifferentiated writing disorders No dysgraphia Vascular aetiology (n 5 40) Traumatic aetiology (n 5 11) Other aetiology (n 5 2) All patients (n 5 53) 7 3 10 10 9 1 – – 6 1 4 – – – 2 – – – 7 3 18 11 13 1 Many contemporary models assume the existence of at least two writing routines, one lexical and one at subwordlevel. In this framework, the first routine is the only option possible when writing words with unpredictable or irregular spelling, the second is the only option when writing nonwords. Italian is a language with quite regular spelling, so that the great majority of words may be written along the subword-level routine. For this reason, it has often been claimed (e.g. Denes et al., 1996) that writing deficits with features of surface dysgraphia (i.e. due to damage of the lexical routine only) should be less frequent among Italian patients. However, in spite of the overall regularity of the Italian orthography, some phones have more than one graphemic realization, though only one is correct for a given lexeme. On the other hand, the efficient use of the subword-level routine requires a correct acoustic-to-phonological conversion to allow the isolation of the single phones to be routed to the phonological-to-orthographic conversion. The relevance of a phonological analysis level had already been stressed by Luria et al. (1969). These authors suggested that ‘the task of writing a given word [whether independently or from dictation] begins with the process of analysis of the phonetic composition of the word, or in other words, with the breaking down of the phonetic stream of living speech into isolated phonemes’. This acoustic-analysis level should depend on the variables determining the complexity of this process, i.e. the presence of consonant clusters or the phonetic-acoustic aspects of the single phones (e.g. plosive versus continuant). Control subjects from the normative sample (Luzzatti et al., 1994a, b) write all regular words almost perfectly, irrespective of either the phonetic-acoustic aspects of the phones, or of the presence of consonant clusters or of the type of conversion rules (one-to-one versus syllabic rules). Older subjects made more errors when writing loan-words which do not follow the regular Italian orthography. This seems to be due simply to the recent appearance of these items in the Italian lexicon and, therefore, to a lack of acquisition of their orthography by older subjects. The effect of age on writing non-words is, however, more difficult to explain. On the one hand, it may be due to a peripheral mechanism by which a loss of hearing, however mild, can lower the performance of writing nonwords, due to the lack of lexical feedback. On the other, impaired writing of non-words in ageing could be explained by the results of Bisiacchi et al. (1989) which demonstrated that the processing of non-words puts a higher load on the 1730 C. Luzzatti et al. Fig. 3 Information-processing model of word naming, confrontation naming and writing [from Patterson (1986), modified]. phonological short-term memory, a function that has been shown to undergo a progressive impairment in ageing (Orsini et al., 1987; Spinnler and Tognoni, 1987). Aphasic patients made more errors when writing words with unpredictable spelling and non-words. Comparing performances on the different subtests, aphasic subgroups (Broca’s, Wernicke’s and anomic aphasia) differ in severity, but the profile shape is almost identical. The variables influencing the outcome along the subword-level routine also show a similar profile of impairment across aphasic subgroups. Obviously, the classification of patients according to aphasic syndromes does not imply that there is an identical cognitive disorder in all subjects sharing the same aphasiological label: on the contrary, a similar distribution of dysgraphic subtypes across aphasic syndromes is a proof of the manifold composition within these groups of subjects. Preliminary results from a comparable study of reading disorders (C. Luzzatti, M. Frustaci, C. Guarnaschelli, M. Tariccó, G. Zonca, unpublished results) seem to suggest a different pattern of impairment with respect to dysgraphia; phonological and deep dyslexic disorders are more frequently associated with agrammatism, while surface dyslexia is associated with jargon aphasia. It would therefore seem that, in Italian at least, reading and writing undergo a different breakdown pattern. The profiles of the individual patients were analysed with a linear model that included the frequency of each item and its rate of difficulty for the control subjects. The choice of this stricter criterion calls for comment. Let us first consider the case of word frequency. Non-words have, by definition, a frequency value of zero. Confusion between two variables of the model, i.e. type of items and word frequency, could therefore be suggested. As a consequence, adjustment for frequency could artifactually affect the word/non-word difference and, therefore, the incidence of phonological dysgraphia. Even if this effect is theoretically possible, we assume that the comparison of performances with words and non-words identifies a difference between processing routines that cannot simply be reduced to the effect of the stimulus frequency. In fact, this possible bias did not reduce the Diagnosis of writing disorders rate of dissociated patterns significantly, as the number of phonologically dysgraphic patients before frequency adjustment was eight, and after adjustment for frequency and stimulus difficulty it was only reduced to seven. Furthermore, as the items included in the different sets were matched for word frequency, it did not affect the comparisons between sections of the test. A further observation concerns the policy of adjusting by item difficulty, as assessed in control subjects. The aim of this adjustment is obviously not to cancel the fact that words with unpredictable transcription may be ‘more difficult’ than regular words, but to test whether the difficulty gradient observed in the patients was proportional to that observed in control subjects. For the above-mentioned reasons we decided to adopt a stricter criterion for the identification of dissociated patterns of dysgraphia, where possible effects of interference of the patients’ performances were partialled out by an adjustment of the scores by item difficulty and wordfrequency effect. The multiple analysis of single cases showed the expected dissociation patterns. A first group of subjects showed a pattern of deficit that corresponds to the diagnosis of surface dysgraphia, while a second group showed a pattern corresponding to the diagnosis of phonological dysgraphia. A further group of subjects showed mixed damage both for words with unpredictable spelling and for regular non-words, but better performance for regular words. There are two possible explanations of this mixed pattern of impairment. According to the classical logogen model (see Fig. 3), this pattern of disruption could be explained as being the result of two separate functional lesions, one at the level of the auditory-to-phonological conversion, the other of the orthographic output lexicon; writing to dictation would therefore be possible only for regular words along an indirect circuit passing through the phonological output lexicon, the phonological buffer and the phonological-to-orthographic conversion unit. However, a pattern of disruption characterized by a selective impairment in writing words with unpredictable spelling and non-words, with an almost preserved spelling of regular words could also account for the mutual interaction of the lexical and the subword-level routines with the writing of regular words (as a consequence of cerebral damage, both routines feed the orthographic buffer with a blurred representation); the performance of mixed dysgraphic patients on writing both words with unpredictable orthography and non-words is therefore impaired. An interaction of the two routines (‘summation’ hypothesis), however, is open to various differing interpretations. A first hypothesis is that the two routines already interact in normal subjects; a similar account has been proposed for normal reading by Hillis and Caramazza (1991). Alternatively, the interaction of the two routines may be a compensatory phenomenon that only accounts for the pattern of performance of mixed dysgraphic patients: while neither of the two routines is sufficient for writing words with unpredictable orthography and non-words, their interaction 1731 allows a better performance with the writing of regular words. A further account assumes the so called ‘horse race’ explanation, for which each of the two routines process regular words independently, both in normal subjects and in mixed dysgraphic patients. Two independent race horses would increase, a priori, the probability of better performance in normal subjects, as well as the possibility of success in the mixed dysgraphic patients. In the introduction, a possible selective impairment of the syllabic subword-level conversion rules was predicted. In fact, three patients showed a dissociated damage of these rules alone. Another prediction made was a possible damage to the auditory-to-phonological conversion, a disorder that would determine a less severe impairment of words composed entirely of continuant phones (vowels and fricative, liquid or nasal consonants), words that are thus more easily analysed along the auditory-to-phonological conversion unit. This phenomenon seems to be rare and was found in only four cases. A frequency effect is usually more common in phonological than in surface dysgraphic disorders, as could be predicted from a writing performance along the lexical routine only. A final issue is the possible difference underlying the process of writing in English and in a language with shallow orthography like Italian. In a recent study, Ardila et al. (1996) stressed the greater relevance of the subword-level routine for the processing of written language in Spanish. However, the writing task used by these authors did not include words with irregular or unpredictable orthography and non-words; unfortunately, the absence of these variables precluded, per se, an identification of the dysgraphic patterns underlying phonological and surface dysgraphia. The results of the present study demonstrated that current psycholinguistic models of written language also apply to languages with shallow orthography. An important difference, however, is the degree of activity of each routine; the lexical route is crucial in languages with irregular spelling like English and French, but less important in a language with predominantly shallow orthography like Italian. Acknowledgements We wish to thank Erminio Capitani and the anonymous referees of Brain for their helpful critical comments and Frances Anderson and Rosemary Allpress for her careful review of the English version of the manuscript. This research was supported by a Grant from the Italian Ministero dell’Università e della Ricerca Scientifica e Tecnologica (MURST) to C.L. and from the Fondazione Valduce to A.D.T. Portions of this paper were presented at the 15th European Workshop on Cognitive Neuropsychology, Bressanone, January 19–24, 1997, and at the National Congress of the Associazione Italiana di Psicologia, Sezione di Psicologia Sperimentale, Capri, September 22–24, 1997. 1732 C. Luzzatti et al. References Aitkin M, Anderson D, Francis B, Hinde J. Statistical modelling in GLIM. Oxford: Clarendon Press; 1989. Ardila A, Rosselli M, Ostrosky-Solis F. Agraphia in the Spanish language. Aphasiology 1996; 10: 723–39. Baxter DM, Warrington EK. Category specific phonological dysgraphia. Neuropsychologia 1985; 23: 653–66. Beauvois M-E, Dérouesné J. Lexical or orthographic agraphia. Brain 1981; 104: 21–49. Bisiacchi PS, Cipolotti L, Denes G. Impairment in processing meaningless verbal material in several modalities: the relation between short-term memory and phonological skills. Quart J Exp Psychol 1989: 41a: 293–319. PJ, Bruyn GW, editors. Handbook of clinical neurology, Vol. 3. Amsterdam: North-Holland; 1969. p. 368–433. Luzzatti C, Willmes K, De Bleser R. Aachener Aphasie Test (AAT) – Versione Italiana. Firenze: Organizzazioni Speciali; 1994a. Luzzatti C, Laiacona M, Allamano N, De Tanti A, Inzaghi MG, Lorenzi L. An Italian test for the diagnosis of acquired writing disorders: construction principles and normative data. Ricerche Psicologia 1994b; 18: 137–60. McCullagh P, Nelder JA. Generalised linear models. London: Chapman and Hall; 1983. Orsini A, Grossi D, Capitani E, Laiacona M, Papagno C, Vallar G. Verbal and spatial immediate memory span: normative data from 1355 adults and 1112 children. Ital J Neurol Sci 1987; 8: 539–48. Bortolini U, Tagliavini C, Zampolli A. Lessico di frequenza della lingua Italiana Contemporanea. Milano: Garzanti; 1972. Patterson KE. Lexical but non semantic spelling? Cogn Neuropsychol 1986; 3: 341–67. Bub D, Kertesz A. Deep agraphia. Brain Lang 1982; 17: 146–65. Patterson KE, Marshall JC, Coltheart M. Surface dyslexia. London: Lawrence Erlbaum; 1985. Coltheart M, Patterson KE, Marshall JC. Deep dyslexia. London: Routledge & Kegan Paul; 1980. De Bleser R, Luzzatti C. Models of reading and writing and their disorders in classical German aphasiology. Cogn Neuropsychol 1989; 6: 501–13. Denes GF, Cipolotti L, Zorzi R. Dislessie e disgrafie acquisite. In: Denes GF, Pizzamiglio L, editors. Manuale di neuropsicologia. 2nd ed. Bologna: Zanichelli; 1996. p. 386–422. [English translation: Aquired dyslexias and dysgraphias. In: Handbook of Clinical and Experimental Neuropsychology. London: Psychology Press, 1998]. Harris M, Colheart M. Language processing in children and adults. London: Routledge & Kegan Paul; 1986. Hillis AE, Caramazza A. Mechanisms for accessing lexical representations for output: evidence from a category-specific semantic deficit. Brain Lang 1991; 40: 106–44. Luria AR, Naydin VL, Tsvetkova LS, Vinarskaya EN. Restoration of higher cortical function following local brain damage. In: Vinken Shallice T. From neuropsychology to mental structure. Cambridge: Cambridge University Press; 1988. Shallice T. Phonological agraphia and the lexical route in writing. Brain 1981; 104: 413–29. Spinnler H, Tognoni G. Standardizzazione e taratura italiana di test neuropsicologici. Ital J Neurol Sci 1987; 8 Suppl 8: 1–120. Wernicke C. Nervenheilkunde. Die neueren Arbeiten über Aphasie. Fortschr Med 1885–1886; 3: 824–30; 4: 371–7, 463–82. [English translation by R. De Bleser. Neurology: recent contributions on aphasia. Cogn Neuropsychol 1989; 6: 547–69]. Willmes K. An approach to analyzing a single subject’s scores obtained in a standardized test with application to the Aachen Aphasia Test (A.A.T.). J Clin Exp Neuropsychol 1985; 7: 331–52. Received October 8, 1997. Revised February 1, 1998. Second revision May 1, 1998. Accepted May 18, 1998 Diagnosis of writing disorders Appendix Derandomized list of the items used in the writing task [WF 5 word frequency (from Bortolini et al., 1972)] Section A Part Words WF Part Words WF 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 3 3 3 3 3 3 3 3 4 4 4 4 4 4 4 4 4 mare mano sole muro vino mulo lume faro filo remo lavoro numero nuvola minerale fenomeno semaforo sinonimo sifone visone somaro senso forma frase marmo nervo frana sfera farsa selva salsa valle ferro messa sonno villa molla muffa masso renna 223 196 173 93 78 10 10 9 5 0 267 149 27 26 21 0 0 0 0 0 123 119 34 33 19 8 0 0 0 0 83 69 47 41 30 7 5 0 0 5 5 5 5 5 5 5 5 5 5 6 6 6 6 6 6 6 6 6 6 7 7 7 7 7 7 7 7 7 7 8 8 8 8 8 8 8 8 8 8 capo tipo dito coda buco topo buca baco tubo diga monte clima festa spesa prato fusto trave lardo mirto stelo notte letto matto latte babbo lutto fetta tappo ratto mappa strada fronte stampa sponda nastro crosta tromba frusta fulcro filtro 145 128 45 9 5 11 9 8 3 0 144 88 78 50 49 13 7 0 0 0 228 176 87 32 27 10 9 0 0 0 311 120 28 11 8 8 6 3 0 0 ascia Section B Words WF cane scala gara gola scopa chiave schifo scheda ghiro ghisa valigia bacio fascia adagio 163 49 40 34 0 48 23 10 0 0 48 41 23 12 0 1733 1734 C. Luzzatti et al. Section C Section D Words WF Words WF società coscienza scienza igiene usciere ente scena conoscenza ascella macello migliaia paglia aglio caviglia vaniglia Italia milione olio vigilia balia segno compagno ognuno pugnale ragno niente genio geranio paniere cerniera libro litro fibra zebra cetra quattro labbro febbre fabbro spettro quarto aquila squalo quarzo squama liquore quota equo iniquo obliquo cuore scuola scuotere cuoio cuoco 110 34 31 5 0 202 45 20 0 0 42 8 0 0 0 256 145 74 10 8 215 59 35 9 0 588 13 7 0 0 86 12 9 0 0 193 34 16 0 0 51 9 0 0 0 11 0 0 0 0 136 102 19 12 9 hobby brandy blue jeans baby-sitter weekend robot chalet nightclub 0 0 0 0 0 0 0 0 Section E Part Non-words 1 1 1 1 1 2 2 2 2 2 3 3 3 3 3 4 4 4 4 4 5 5 5 5 5 nise nifo ralo vona relo vimàne forèla rinàfo ramàsola lesònimo fella seffa sovva nissa sinno tido pabo bita dute puda nitta loppa rebba mippo satto