"Apperceptive" alexia in posterior cortical atrophy

The most common presenting complaint in posterior cortical atrophy (PCA) is reading difficulty. Although often described as an alexia without agraphia, alexia in PCA may have multiple causes, including a primary visuoperceptual etiology, attentional alexia, and central reading difficulty. This study evaluated 14 patients with early PCA and disturbances in reading ability in comparison to 14 normal controls. All 14 patients had a progressive disorder of complex visual functions and neuroimaging evidence of occipitoparietal dysfunction. They underwent a task requiring identification of single letters with and without flanking distractors. They also read single words consisting of regular English spelling or irregular grapheme-phoneme correspondence (irregular words) and pronounceable nonsense words (pseudowords). The PCA patients made errors in letter identification when letters were flanked by visually similar letters or numbers. They could read most single regular and irregular words but made visual errors and had particular trouble with pseudowords. They could not use a letter-by-letter reading strategy effectively. The PCA patients had similar difficulties on other visuoperceptual tests. These findings are consistent with an alexia manifested by perceptual and attentional difficulty on attempting serial visual processing of letters in the context of other letters. This "apperceptive alexia" results when the configuration of letters into words is impaired during letter-by-letter reading. Disproportionate difficulty reading pseudowords suggests an additional impairment in phonological processing. PCA patients have variable neuropathology and individual patients may have other contributions to their reading impairment.     

Remediation of written language

Written communication involves the linking of ideas and words to their appropriate spellings, and then moving the hand to actually write the desired words. Acquired impairments of writing are referred to as agraphia and can result from damage to various stages of the writing process. These impairments may reflect degraded knowledge about spelling and the correspondences between sounds and letters or difficulty with the selection and formation of letters. Characteristic features of agraphia syndromes are reviewed in this article, along with example approaches to remediation. The treatments variously serve to strengthen weakened abilities, take advantage of residual skills, and develop compensatory strategies.     

Mirror writing and reversing single letters in stroke patients and normal elderly

Abstract Mirror writing (MW) refers to the production of individual letters or whole word strings in reversed direction. When held to a mirror, these letters or words can be read normally. We observed MW in a considerable number of stroke patients. Of the 86 patients screened 15 (17.5%) showed at least one instance of mirror writing in any of the tasks. Both right (14% of 36 patients) and left (20% of 50 patients) hemisphere damaged patients produced reversed letters only when writing with their left hand, respectively the contralesional and ipsilesional hand. The dissociated performance between the two hands in brain damaged patients is relevant to the interpretation of MW because, unlike all other peripheral dysgraphias, MW affects the non-dominant hand only. Importantly, healthy elderly also showed MW solely when writing with their left hand (6.9% of 86 participants). MW in controls was less frequent but qualitatively similar to that observed in brain damaged patients. This finding is consistent with the motor interpretation of MW that assumes an inability to transform the stored letter forming programmes for left hand writing. However, several cases have been reported in the literature of a more pervasive form of MW whereby patients mirror reverse entire words or sentences. This pattern has been observed in children learning to write but it has never been observed in healthy adult volunteers. We propose that the diagnosis of MW should be limited to the reversal of whole words, multi-digit numbers and full sentences, which reveal a disorder in coding the correct direction of writing rather than an inability to accomplish the correct spatial orientation of single letters.     

Dysgraphia for letters: a form of motor memory deficit?

A case of pure dysgraphia is presented in which the patient could accurately copy letters which she could not write. The patient did not show any evidence of significant reading or speech impairment or any buccofacial or limb apraxia. Both oral and "block spelling" performance were intact. The writing impairment, which was bilateral, appeared to consist of a memory difficulty for the motor movements associated with letters. The dysgraphia was shown to be specific to letters as the patient was able to transcribe certain numbers and patterns which were similar to letters in their visuospatial complexity. It is suggested that dysgraphia for letters may represent a specific type of motor memory deficit, dissociable from copying skills and the ability to draw letter-like forms.     

Progressive peripheral agraphia

We describe RW, a patient who presented with writing difficulty that deteriorated over time. While her graphemes were typically legible, her writing was extremely slow, and her letters were written in an inconsistent and heterogeneous manner (e.g. each "a" in the word "banana" was produced in a different way). Her mental imagery of letters was impoverished, and she also produced allographic errors in her writing. She had some spelling errors as well, but many of these were due to omissions, perseverations, and motor operations. A positron emission tomography scan demonstrated superior parietal occipital and superior frontal defects that were more evident on the left than the right. Our observations are consistent with the hypothesis that RW has a deficit retrieving physical letter forms as manifested by her heterogeneous and slow production of letter forms. This disruption of grapheme retrieval is associated with interruption of a superior frontal-parietal system in the left hemisphere.     

Writing disorders in primary progressive aphasia]

We investigated longitudinally three patients with primary progressive aphasia (PPA) who exhibited fluent aphasia at the early stage, in terms of writing disorders. The writing disorders were the most striking during the aphasia quotient (AQ) was 50-60 for all these patients. The characteristic features were as follows: (i) several types of perseverative errors, especially on spontaneous writing rather than on dictation (ii) confusion between letters and pictures (iii) preserved copying ability and (iv) total loss of writing ability at the final stage. Additionally, through the progression, linguistic level of the perseverative errors changed from sentence to word and finally to phoneme. The results suggest that the fluent type PPA patients have difficulty to recall proper letters and to arrange them in correct order following the writing plan, in addition to disinhibition and lexical stereotyping which were commonly observed in perseverative patients. The results also suggest that their writing disorders seem to be based on difficulty of letter manipulation as symbols.     

Writing Kanji without semantics in a case with probable Alzheimer's disease]

We examined a patient (NM) with probable Alzheimer's disease who showed phonologically plausible errors in kanji (logogram) writing. In semantic tasks, she showed no deficits in pointing or naming but had difficulty in more complex tasks such as proverb comprehension. In reading aloud of kanji words, she could read most kanji words correctly and showed little phonologically plausible reading errors. She performed poorly in lexical decision and on-reading of one-letter kanji (Sino-Japanese pronunciation derived from the Chinese language at the time of borrowing). Writing to dictation demonstrated no mistakes in kana letters and words, but many errors in kanji, which were phonologically equivalent but semantically inappropriate. To explore the relationship between the writing errors in kanji words and comprehension of the word meanings, we selected 33 words that she made phonologically plausible writing errors. We gave her the following five tasks using these words; 1) to ask meanings of the words, 2) to dictate the words, 3) to dictate sentences including these words, 4) to discriminate appropriate target words from distracters including her own erroneous responses, and 5) to write these words again. She showed no consistent errors in these tasks. In some occasions, she could write correct kanji words without understanding word meanings. She also showed phonologically plausible writing errors in spite of describing correct word meanings. In Japanese, word meaning deficits like Gogi aphasia were thought to cause phonologically plausible writing errors. As the impairments of word meanings in NM are comparatively mild, the underpinning of her kanji agraphias might be different from that of phonologically plausible errors in Gogi aphasia. It would be suggested that she frequently wrote phonologically equivalent errors because of her lexical deficits in spite that her phonological processing was preserved. Furthermore, she would not necessarily use the semantics (word meanings) of kanji words during dictation.     

Phonemic fluency in Portuguese-speaking subjects in Brazil: ranking of letters

Phonological verbal fluency studies in English most commonly employ the letters F-A-S as stimuli. We assessed the production of words with these and 14 other letters in Portuguese-speaking healthy subjects (n = 74). The letters F-A-S were ranked among the easiest to produce words in one minute, which is consistent with the findings of studies with English-speaking subjects. There were differences in the overall ranking of letters depending on whether the total word number or the latency between words were considered. Our findings provide a databank of phonological verbal fluency performance using different stimuli in Portuguese, and demonstrate that the ranking of the letters F-A-S is comparable between the English and Portuguese languages in terms of the level of difficulty to produce words, when the task is used in its traditional format.     

Letter position dysgraphia

The article describes AE, a Hebrew-speaking individual with acquired dysgraphia, who makes mainly letter position errors in writing. His dysgraphia resulted from impairment in the graphemic buffer, but unlike previously studied patients, most of his errors related to the position of letters rather than to letter identity: 80% of his errors were letter position errors in writing, and only 7% of his errors were letter omissions, substitutions, and additions. Letter position errors were the main error type across tasks (writing to dictation and written naming), across output modalities (writing and typing), and across stimuli, e.g., migratable words (words in which letter migration forms another word), irregular words, and nonwords. Letter position errors occurred mainly in the middle letters of a word. AE's writing showed a significant length effect, and no lexicality, migratability, or frequency effects. His letter position deficit was manifested selectively in writing; he made no letter position errors in reading, demonstrating the dissociability of letter position encoding in reading and writing. These data support the existence of a letter order function in the graphemic buffer that is separate from the function responsible for activating letter identities.     

Fusiform type alexia: pure alexia for words in contrast to posterior occipital type pure alexia for letters

OBJECTIVE: To clarify the behavioral differences between patients with pure alexia from different lesions. METHODS: Two patients with pure alexia caused by damage to the fusiform or posterior occipital gyri were given reading and writing tests including kanji (Japanese morphograms) and kana (Japanese phonetic writing). RESULTS: Patient 1 (pure alexia from a fusiform gyrus lesion) had difficulty reading both kanji and kana, with kanji reading more impaired, and imageability and visual complexity effects (imageable or less complex words/characters were read better than nonimageable or more complex words/characters), whereas patient 2 (pure alexia from a posterior occipital gyri lesion) showed selective impairment of kana reading. CONCLUSION: Pure alexia for kanji (and kana; fusiform type) is characterized by impairments of both whole-word reading, as represented in kanji reading, and letter identification, and is different from pure alexia for kana (posterior occipital type) in which letter identification is primarily impaired. Thus, fusiform type pure alexia should be designated pure alexia for words, whereas posterior occipital type pure alexia should be designated pure alexia for letters.     

The development of writing skills in 4-year-old children with and without specific language impairment

ABSTRACT

Research shows that many preschool children with specific language impairment (SLI) have difficulty acquiring literacy skills including phonological awareness, print concepts, and alphabet knowledge. Limited research suggests that preschool children with SLI also have difficulty with emergent writing tasks such as name writing and word writing. In typically developing children, research indicates that emergent writing skills are acquired in a developmental sequence: (1) linearity, (2) segmentation, (3) simple characters, (4) left-right orientation, (5) complex characters, (6) random letters, and (7) invented spelling. This study compared the emergent writing skills of 4-year-old children with SLI (n = 22) to their age- and gender-matched peers (n = 22). Results indicated that children with SLI demonstrate difficulty with a variety of writing tasks, including letter writing, name writing, word writing, and sentence writing when compared to their typically-developing peers. Children with SLI followed the same developmental sequence in acquiring writing skills as their typically-developing peers.     

Visually- and motor-based knowledge of letters: evidence from a pure alexic patient

We describe a patient, VSB, whose reading was impaired as a consequence of a left temporal-parietal lesion, whereas writing was relatively preserved. At variance with other pure alexic patients described in the literature, VSB claimed to have become unable to mentally visualise letters and words. Indeed, his performance on a series of tests tapping visual mental imagery for orthographic material was severely impaired. However, performance on the same tests was dramatically ameliorated by allowing VSB to trace each item with his finger. Visual mental imagery for non-orthographic items was comparatively spared. The pattern of dissociation shown by VSB between impaired visual mental imagery and relatively preserved motor-based knowledge for orthographic material lends support to the view that separate codes, respectively based on visual appearance and on motor engrams, may be used to access knowledge of the visual form of letters and words.     

Aphasia and the process of revision in writing a text

Most of the previous research on aphasia and writing ability concentrates on the production of words in isolation. The purpose of the current study was to examine the process of producing written texts by clients with aphasia. By using keystroke logging, it was possible to analyse the participants' ongoing work during text writing. Results showed that the participants with aphasia composed their texts in what may be described as a linear way. Edits concerning syntax or text structure were almost absent in the subjects' data, but they spent much time and effort on revising smaller units of text, that is, letters and words, possibly as a result of changing their minds or not being able to realize their intentions. However, these changes did not always result in correctly written words in the final text. The findings are discussed in relation to current writing theories.     

Allographic agraphia: a case study

We report the case of patient MN, diagnosed with frontotemporal dementia, who exhibited a severe impairment in writing letters and words in upper-case print in the face of accurate production of the same stimuli in lower-case cursive. In contrast to her written production difficulties, MN was unimpaired in recognizing visually presented letters and words in upper-case print. We find a modest benefit of visual form cueing in the written production of upper-case letters, despite an inability to describe or report visual features of letters in any case or font. This case increases our understanding of the allographic level of letter-shape representation in written language production. It provides strong support for previous reports indicating the neural independence of different types of case and font-specific letter-shape information; it provides evidence that letter-shape production does not require explicit access to information about the visual attributes of letter shapes and, finally, it reveals the possibility of interaction between processes involved in letter-shape production and perception.     

Aphasia and the process of revision in writing a text

Most of the previous research on aphasia and writing ability concentrates on the production of words in isolation. The purpose of the current study was to examine the process of producing written texts by clients with aphasia. By using keystroke logging, it was possible to analyse the participants' ongoing work during text writing. Results showed that the participants with aphasia composed their texts in what may be described as a linear way. Edits concerning syntax or text structure were almost absent in the subjects' data, but they spent much time and effort on revising smaller units of text, that is, letters and words, possibly as a result of changing their minds or not being able to realize their intentions. However, these changes did not always result in correctly written words in the final text. The findings are discussed in relation to current writing theories.     

The field-by-length effect in word processing: a failure to confirm

It has been shown that the left hemisphere superiority for processing words applies only to long words by Young and Ellis (1985). These authors defined the length as the number of letters. Bruyer and Janlin (1989) compiled supporting evidence by contrasting the number of letters and the physical size of the stimuli: Short words were made as long as "long" words by the use of blank spaces between the letters. In the present study, another control was used: The physical size of the stimuli was manipulated by means of the viewing distance (nearer short words were as long as the long words). Thirty-six subjects were submitted to 720 trials in which two words appeared for 150 ms, one in each visual hemifield. The subject reported the two words in a defined order. The results did not clearly support the previous studies.     

Selective lower-case letter ideational dysgraphia.

A case study of a man with a selective ideational dysgraphia for lower-case letters is described. His spelling skills were only very mildly impaired and there was no evidence of other praxic or visuoconstructional impairments. The findings are discussed in the context of information processing models. It is suggested that the representation of upper- and lower-case letters must be fairly independent.     

Pure agraphia after infarction in the superior and middle portions of the left precentral gyrus: Dissociation between Kanji and Kana

The present study describes a Japanese patient with pure agraphia displaying differential disturbances in processing Kanji (morphogram) and Kana (syllabogram) letters after an infarction in the middle and superior portions of the left precentral gyrus. Kana errors reflected the patient’s difficulty with retrieving both motor and visual letter images, whereas Kanji errors included partial letter stroke omissions or additions. This present case suggests that differences in writing disturbances between Kana and Kanji letters are caused by a differential dependency on letter motor images.