Apractic agraphia in a patient with normal praxis

Most right-handed crossed aphasics are not apractic. They usually have agraphia characterized by misspellings but retain the ability to write well-formed graphemes. We describe a right-handed patient with a right parietal lesion who was aphasic and not apractic. He was unable to write any formed graphemes despite a relatively preserved ability to spell aloud. We postulate that praxis and writing are dissociated in this patient because the motor engrams for praxis were located in his left hemisphere and the engrams for writing were in his right hemisphere. In addition, he comprehended commands for limb motor activities (praxis) far better than he comprehended other speech. This suggests that in this patient the areas used to comprehend limb motor commands may be anatomically distinct from areas important in comprehending other aspects of speech.     

Pure agraphia and Gerstmann's syndrome as a visuospatial-language dissociation: an experimental case study

A right-handed man suffered a left parieto-occipital cerebral infarction, causing agraphia with Gerstmann's syndrome but without major aphasia, alexia, or apraxia. Oral spelling was superior to written spelling. Experiments were performed involving (1) analysis of errors in writing, (2) tasks of visual imagery, and (3) identifying letters drawn without leaving a visual trace. The results suggest that the agraphia and Gerstmann's syndrome are due to a dissociation of language skills and visuospatial skills caused by a dominant parieto-occipital lesion.     

Writing with the right hemisphere

We studied writing abilities in a strongly right-handed man following a massive stroke that resulted in virtually complete destruction of the language-dominant left hemisphere. Writing was characterized by sensitivity to lexical-semantic variables (i.e., word frequency, imageability, and part of speech), semantic errors in writing to dictation and written naming, total inability to use the nonlexical phonological spelling route, and agrammatism in spontaneous writing. The reliance on a lexical-semantic strategy in spelling, semantic errors, and impaired phonology and syntax were all highly consistent with the general characteristics of right hemisphere language, as revealed by studies of split-brain patients and adults with dominant hemispherectomy. In addition, this pattern of writing closely resembled the syndrome of deep agraphia. These observations provide strong support for the hypothesis that deep agraphia reflects right hemisphere writing.     

Dissociations of writing and praxis: Two cases in point

For normal writing it is essential that both motoric and linguistic competence be present; disruption of one or the other of these faculties may result in qualitatively different types of agraphia. Two right-handed patients became agraphic after left hemisphere lesions; pure apraxic agraphia in the absence of limb apraxia developed in one patient and pure linguistic agraphia in association with severe ideomotor limb apraxia in the other. The performance of these patients not only serves to illustrate the dissociation between the motoric and linguistic faculties that underlie writing but also confirms that ideomotor limb apraxia and apraxic agraphia are distinct and dissociable entities.     

Written spelling agraphia

When a disorder of single word writing is seen in conjunction with preserved oral spelling and intact written grapheme formation ("written spelling agraphia"), the deficit may be presumed to lie somewhere between letter choice and written motor output. Two potential deficits are considered: (1) visual letter codes are not activated properly and (2) the information contained within properly activated visual letter codes fails to reach intact graphic motor patterns. Two patients with written spelling agraphia were each given a series of tests aimed at distinguishing between the two possibilities. Results suggest that the written spelling agraphia seen in these two patients arises from different underlying deficits. The results are discussed in terms of the patients' CT scan lesion sites, which were markedly different.     

The transcoding processes in patients with agraphia to dictation

The main purpose of the present study is to prove that the mechanism of transcoding, that is, of transposition of certain units of a sign system into the corresponding ones of another sign system, is an independent mechanism. We attempted to demonstrate this thesis with reference to certain transcoding processes within the verbal function of writing to dictation, in particular, by examining the agraphic disturbances in aphasics on this form of writing. We found that this type of agraphia in patients with an intact input stage (i.e., intact auditory and visual word perception) but with a blocked shift from the phonetic to the graphemic level (even in cases with intact auditory and visual word perception), or in those with a blocked shift to the grapho-motor one (even in cases with intact copying), is due to disturbed mechanisms of transcoding. The fact that in patients with pure writing-to-dictation disability copied writing is not disturbed proves that the transcoding process is selectively blocked. Transcoding processes in copying and total agraphia are discussed by comparison.     

Varieties of alexia from fusiform, posterior inferior temporal and posterior occipital gyrus lesions

Reading impairments of three alexia patients, two pure alexia and one alexia with agraphia, due to different lesions were examined quantitatively, using Kanji (Japanese morphogram) words, Kana (Japanese phonetic writing) words and Kana nonwords. Kana nonword reading was impaired in all three patients, suggesting that widespread areas in the affected occipital and occipitotemporal cortices were recruited in reading Kana characters (corresponding to European syllables). In addition, the findings in patient 1 (pure alexia for Kanji and Kana from a fusiform and lateral occipital gyri lesion) and patient 2 (pure alexia for Kana from a posterior occipital gyri lesion) suggested that pure alexia could be divided into two types, i.e. ventromedial type in which whole-word reading, together with letter identification, is primarily impaired because of a disconnection of word-form images from early visual analysis, and posterior type in which letter identification is cardinally impaired. Another type of alexia, alexia with agraphia for Kanji from a posterior inferior temporal cortex lesion (patient 3), results from deficient whole-word images of words per se, and thus should be designated "orthographic alexia with agraphia". To account for these impairments, a weighted dual-route hypothesis for reading is suggested.     

Selective uppercase dysgraphia with loss of visual imagery of letter forms: a window on the organization of graphomotor patterns

We report a patient who, after a left parieto-occipital lesion, showed alexia and selective dysgraphia for uppercase letters. He showed preserved oral spelling, associated with handwriting impairment in all written production; spontaneous writing, writing to dictation, real words, pseudowords, and single letters were affected. The great majority of errors were well-formed letter substitutions: most of them were located on the first position of each word, which the patient always wrote in uppercase (as he used to do before his illness). The patient also showed a complete inability to access the visual representation of letters. As demonstrated by a stroke segmentation analysis, letter substitutions followed a rule of graphomotor similarity. We propose that the patient's impairment was at the stage where selection of the specific graphomotor pattern for each letter is made and that the apparent selective disruption of capital case was due to a greater stroke similarity among letters belonging to the same case. We conclude that a visual format is necessary neither for spelling nor for handwriting.     

Alexia with agraphia due to the left posterior inferior temporal lobe lesion--neuropsychological analysis and its pathogenetic mechanisms

We report three cases of alexia with agraphia due to the left posterior inferior temporal lesions. In Case 1, the reading disability was more prominent in the use of Kana than in the use of Kanji, which is similar to previously reported cases of alexia with agraphia due to angular gyrus lesion. In Cases 2 and 3, by contrast, the reading disability was more prominent in the use of Kanji than in the use of Kana. In spontaneous writing and dictation, the disability was more pronounced in the use of Kanji compared with the use of Kana. In each of the three cases, the CT scan and positron emission tomography showed a localized lesion in the lower part of the left posterior temporal lobe. A typical form of an alexia with agraphia could be caused not only by the left angular lesion but also by the left posterior inferior temporal lesion. We discuss the neuropsychological analysis and pathogenetic mechanisms of alexia with agraphia due to the left posterior inferior temporal lesion in the comparison of alexia with agraphia caused by the left angular lesion.     

Suppressing visual feedback in written composition: Effects on processing demands and coordination of the writing processes

The goal of this experiment was to investigate the role of visual feedback during written composition. Effects of suppression of visual feedback were analyzed both on processing demands and on on‐line coordination of low‐level execution processes and of high‐level conceptual and linguistic processes. Writers composed a text and copied it either with or without visual feedback. Processing demands of the writing processes were evaluated with reaction times to secondary auditory probes, which were analyzed according to whether participants were handwriting (in a composing and a copying task) or engaged in high‐level processes (when pausing in a composing task). Suppression of visual feedback increased reaction time interference (secondary reaction time minus baseline reaction time) during handwriting in the copying task and not during pauses in the composing task. This suggests that suppression of visual feedback only affected processing demands of execution processes and not those of high‐level conceptual and linguistic processes. This is confirmed by analysis of the quality of the texts produced by participants, which were little, if at all, affected by the suppression of visual feedback. Results also indicate that the increase in processing demands of execution related to suppression of visual feedback affected on‐line coordination of the writing processes. Indeed, when visual feedback was suppressed, reaction time interferences associated with handwriting were not reliably different in the copying task or the composing task but were significantly different when visual feedback was not suppressed: They were lower in the copying task than in the composition task. When visual feedback was suppressed, writers activated step‐by‐step execution processes and high‐level writing processes, whereas they concurrently activated these writing processes when composing with visual feedback.     

Alexia and agraphia with spared spelling and letter recognition abilities

A patient with alexia and agraphia had intact spelling and comprehension of spelled words and used a letter-naming strategy to read and write. We propose that there is a graphemic area important for distinguishing graphemic features and for programming movements used in writing. In this patient this area was not functioning or did not have access to the area of visual word imagés. Therefore, he used an ideographic letter-naming strategy to verbally circumvent his disability and gain access to the area of visual word images.     

Tier 1 and Tier 2 early intervention for handwriting and composing

Three studies evaluated Tier 1 early intervention for handwriting at a critical period for literacy development in first grade and one study evaluated Tier 2 early intervention in the critical period between third and fourth grades for composing on high stakes tests. The results contribute to knowledge of research-supported handwriting and composing instruction that informs practice as school psychologists are empowered to embrace the role of intervention specialist. The first study found that neurodevelopmental training (orthographic-free motor activities and motor-free orthographic activities) led to improved accuracy and legibility of letter formation, but that direct handwriting instruction with visual cues and verbal mediation led to improved automatic handwriting (rate of writing legible letters) and transfer to improved word reading. The second study found that neither motor training nor orthographic training alone added value to direct instruction in automatic letter writing and composing practice in developing handwriting skills, which transferred to improved word reading; but the added motor training did improve performance on a grapho-motor planning task for sequential finger movements that is relevant to composing. A related analysis showed that direct instruction with visual cues and memory delays may reduce reversals. A third study found that adding handwriting to reading instruction improved handwriting but did not add value to reading outcomes for at risk readers; reading instruction alone was beneficial for word reading, decoding, and comprehension. The fourth study showed that comprehensive, explicit instruction in the processes of composition led to more significant improvement, based on group and individual data, than did the regular fourth grade program, on high stakes writing assessment.     

Visual perceptual and handwriting skills in children with Developmental Coordination Disorder

ObjectiveChildren with Developmental Coordination Disorder demonstrate a lack of automaticity in handwriting as measured by pauses during writing. Deficits in visual perception have been proposed in the literature as underlying mechanisms of handwriting difficulties in children with DCD. The aim of this study was to examine whether correlations exist between measures of visual perception and visual motor integration with measures of the handwriting product and process in children with DCD.MethodThe performance of twenty-eight 8–14 year-old children who met the DSM-5 criteria for DCD was compared with 28 typically developing (TD) age and gender-matched controls. The children completed the Developmental Test of Visual Motor Integration (VMI) and the Test of Visual Perceptual Skills (TVPS). Group comparisons were made, correlations were conducted between the visual perceptual measures and handwriting measures and the sensitivity and specificity examined.ResultsThe DCD group performed below the TD group on the VMI and TVPS. There were no significant correlations between the VMI or TVPS and any of the handwriting measures in the DCD group. In addition, both tests demonstrated low sensitivity.ConclusionClinicians should execute caution in using visual perceptual measures to inform them about handwriting skill in children with DCD.     

Transient beneficial effects of excitatory theta burst stimulation in a patient with phonological agraphia after left supramarginal gyrus infarction

We report a patient showing isolated phonological agraphia after an ischemic stroke involving the left supramarginal gyrus (SMG). In this patient, we investigated the effects of focal repetitive transcranial magnetic stimulation (rTMS) given as theta burst stimulation (TBS) over the left SMG, corresponding to the Brodmann area (BA) 40. The patient and ten control subjects performed a dictational words and nonwords writing task before, and 5 and 30 min after they received excitatory intermittent TBS (iTBS) over the left BA 40, the right hemisphere homologous to BA 40, the Wernicke’s area, or the primary visual cortex.ITBS over the left SMG lead to a brief facilitation of phonological non-words writing to dictation. This case study report illustrates that rTMS is able to influence, among other language functions, the phonological loading processes during the written language production in stroke patients.     

Pure agraphia in Romaji after left inferior frontal gyrus infarction: A case of selective deficit in syllable-to-grapheme conversion in Japanese

The Japanese writing system employs two distinct categories of characters: Kana and Kanji. The difference between Kana and Kanji writing corresponds roughly to that between phonological and lexical systems in Western languages. When typing, most Japanese use alphabetical characters based purely on phonological rules. In particular, the Romaji system is used, in which a syllable consists of a single vowel, a consonant–vowel compound (e.g., ka, ki), or a sequence of consonant–y(semivowel)–vowel (e.g., kya, kyu). We describe a right-handed Japanese patient who developed pure agraphia that affected Romaji writing but preserved Kana and Kanji writing and who had a lesion in the left pars opercularis of the inferior frontal gyrus that extended to the anterior precentral gyrus. The patient demonstrated literal paragraphia in spelling Romaji across modalities. Our findings suggested that the patient’s agraphia in Romaji after a confined left frontal infarction was manifested by a selective impairment in syllable-to-grapheme conversion.     

Left non-dominant hand mirror writing

A 38-year-old right-handed woman, who had suffered a left cerebral hemisphere infarction, was studied. She developed right hemiparesis, motor and sensory aphasia, and left hand mirror writing. All possible brain mechanisms involved in writing, either perceptual or motor, were investigated in search of the one responsible for her mirror writing; however, no abnormality was detected. On examination of the left handwriting, in the directionality of writing tracings as related to the body midline, we detected a lack of inversion of the right handwriting motor patterns--at the moment they are transmitted from the left to the right cerebral hemisphere--implicating a motor rather than a perceptual mechanism.     

Crossed aphasia in an illiterate dextral

An 83 year old illiterate, right-handed woman developed a persistent nonfluent aphasia following a right cerebral infarction (crossed aphasia). Computerized axial tomography localized the lesion to the right posterior frontal lobe.It is suggested that the neural mechanisms involved in learning to read and write may be critical for the complete establishment and maintenance of language dominance in the left hemisphere, and that, in this case, the patient's failure to acquire reading and writing skills altered the normal evolution of language lateralization and resulted in the right hemisphere assuming the dominant role.     

Cerebellar-induced apraxic agraphia: a review and three new cases

Apraxic agraphia is a writing disorder due to a loss or lack of access to motor engrams that program the movements necessary to produce letters. Clinical and functional neuroimaging studies have demonstrated that the neural network responsible for writing includes the superior parietal region and the dorsolateral and medial premotor cortex. Recent studies of two cases with atypical lesion localisations in the left thalamus and the right cerebellum support the hypothesis that the written language network is larger than previously assumed. The aim of this study is twofold: (1) to provide a survey of cases of apraxic agraphia published between 1973 and June 2010, and (2) to provide further evidence for a role of the cerebellum in writing via three additional cases who presented with apraxic agraphia after ischemic damage in the cerebellum. Functional neuroimaging studies by means of brain perfusion SPECT showed perfusional deficits in the anatomoclinically suspected supratentorial areas, subserving language dynamics, syntax, naming, writing and executive functioning.     

快速书写条件下硬笔笔迹变量与认知及个性特征的关系

以圆珠笔为书写工具．北京市某中学高一学生为被试,有效数据169人．探讨了在快速抄写条件下,笔迹书写特征与认知及个性的关系：18个笔迹变量可抽取笔压、结构、特征、字体和空间五个反映字的书写特征的因素;书写特征与认知因素间,横、竖笔压与概念形成速度。整篇压与视力追踪、字位与眼手协调相关显著;横笔压与16PF测验中的畏缩退怯——冒险敢为有正相关;竖笔压与艾森克个性因素的N有高相关。     

Ideogram writing in a disconnection syndrome

A case of disconnection-type agraphia coupled with alexia was reported. The patient showed several asymmetrical manual capacities between the two hands, i.e., dissociated difficulty of Kanji (ideogram) writing between the two hands, left unilateral difficulty of Kana (phonogram) writing, right unilateral dyscopia of letters as well as geometrical figures, and right unilateral difficulty in drawing without a model. Anatomically, lesions involved most of the corpus callosum in its posterior portion including the splenium and the left medial occipital lobe. From these data, a possible liguistic capacity of the right hemisphere was suggested.