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PubMed1998

[Pure alexia due to a fusiform gyrus lesion].

We present a patient with pure alexia following a hemorrhagic infarction in the left fusiform gyrus. The symptom began with alexia preferentially disturbed for kana, but during the course of recovery slight agraphia for kanji became pronounced. In the earlier phase, alexia was more severe than agraphia and he could write kanji that he could not read. Furthermore, kinesthetic reading was effective. These findings are consistent with the symptoms of pure alexia, although the fact that a writing disturbance for kanji persisted resembles the profile of alexia with agraphia for kanji due to a posterior inferior temporal lesion. Based on the fact that the posterior inferior temporal lesion showed more severe agraphic symptom and more frequent nonresponse writing errors of kanji, and that our patient's lesion was mainly located in the fusiform gyrus that is medial to the inferior temporal gyrus, we believe that alexia occurred when the inferior temporal gyrus was disconnected from the fusiform gyrus, as a result, visual information could not reach the inferior temporal gyrus in which the visual images of individual kanji are stored.

Aged↗
PubMed1998

[Pure alexia: presentation of a case].

INTRODUCTION AND CLINICAL CASE: A case of pure alexia, secondary to an occipital cerebral infarct, is presented, which initially appearing with bilateral amaurosis of two hours of duration, following by a significant difficulty to read, and according to patient, was a deficit to near vision and by criteria of ophthalmologists and optometrists was a presbyopia. Authors identified a lack of P-300 wave in study of endogenous component of events related potentials (ERP), to task of phonetic discrimination, and its normal registry to task of graphic discrimination. CONCLUSION: Therefore, we confirm the cliniconeurophysiologic diagnosis of a pure alexia without agraphia, by means of this non-invasive method studying cerebral cognitive process.

Cerebral Infarction↗
PubMed1995

[A case of pure alexia whose writing ability with eyes closed was superior to that with eyes open].

We compared the writing ability between eyes open (looking at one's writing) and eyes closed (without looking) in a case of pure alexia. The patient is a 84-year-old right handed man who developed pure alexia following an infarction in the distribution of the left posterior cerebral artery. He showed right homonymous hemianopsia, slight memory disorder and slight anomia. He could not read any kinds of letters and words at all though he could categorize letters: Kana (phonograms), Kanji (morphograms) and Arabic numbers, and he could distinguish the real letters from false ones. He could achieve almost 60-70% of Kana and Kanji dictation, though it was not perfect. He was often confused and could not continue writing correct letters once interrupted. He wrote poorly when looking at what he was writing. So we compared the ability of dictation with his eyes closed, and that with his eyes open. We found the former way never caused confusion and got better results, which was statistically significant (Fisher's exact test (p < 0.05)). It seemed that his visual feedback of his own writing rather caused trouble in his writing. Thus we concluded that input (reading) process and output (writing) process work simultaneously and bi-directionally. Slight impairment of writing in pure alexia patients might be caused by the effect of impairment of input (reading) process, which is simultaneously connected with the output (writing) process.

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PubMed1993

Reading in pure alexia. The effect of strategy.

A number of investigators have demonstrated that patients with pure alexia comprehend briefly presented words which they are unable to explicitly identify. We suggested previously that these patients may read by means of two distinct procedures: a laborious letter-by-letter method and a 'whole-word' procedure which, at least initially, does not support explicit word identification. We report a test of this proposal in a patient with pure alexia. We reasoned that if the patient had access to two distinct and incompatible procedures, he might be induced to switch from one to the other by changing task demands. We found that when instructed to name words, the patient employed a letter-by-letter strategy; in contrast, when instructed to make lexical decision or semantic judgements about rapidly presented words, he appeared to use a 'whole-word' strategy. These data support the hypothesis that two distinct procedures are available to this patient. We argue, further, that is necessary to suppress use of the letter-by-letter strategy to demonstrate whole word reading capability in pure alexics, and that failure to do so may account for negative findings in other cases reported in the literature.

Cerebral Infarction↗
PubMed1988

Resolving metabolic abnormalities in a case of pure alexia.

We report resolving metabolic abnormalities corresponding to clinical improvement in a patient with pure alexia secondary to acute cerebral infarction. Local cerebral glucose metabolism (lCMRgl) was measured with positron emission tomography (PET) using 18F-fluorodeoxyglucose (18F-FDG) close to ictus and 4 1/2 months later. Serial CTs and a subsequent MRI demonstrated small, unchanging left-hemispheric lesions involving the area of the lateral geniculate body and the splenium of the corpus callosum. PET demonstrated the evolution of the metabolic abnormality resulting from intrahemispheric (lateral geniculate) and interhemispheric (splenium) disconnection in the absence of occipital lobe infarction. This case illustrates that cerebral disconnection can result in the syndrome of pure alexia. The factors accounting for focal hypometabolism in the absence of cerebral infarction are discussed.

Brain↗
PubMed1998

Pure alexia and word-meaning deafness in a patient with multiple sclerosis.

OBJECTIVE: To describe pure alexia and auditory comprehension problems in a young woman with multiple sclerosis (MS). PATIENT: A 33-year-old woman with MS who complained of difficulties in reading and comprehending spoken language was referred for a neuropsychological examination. Reading difficulties were confirmed and most of the reading errors were additions, omissions, and substitutions of single letters. While the patient reported that the letters seemed to disappear before her eyes, no general problems with visual attention, visual discrimination, or scanning were detected. No difficulties with spelling were reported. The auditory comprehension deficit is interpreted as a form of a semantic access disorder and is not due to generalized slowing in information processing or conceptual disintegration. CONCLUSIONS: Pure alexia is unusual in MS and to our knowledge only 1 other case has been reported (in Japanese). Memory impairments and slowed information processing are probably the most frequent cognitive sequelae of the disease and, consequently, the literature is biased toward the study of those cognitive domains. However, given the wide distribution of sclerotic plaques in MS, it could be argued that we should expect some variability of cognitive changes in MS. Striking deficits as seen in this patient should make us more sensitive to this possibility.

Adult↗
PubMed1995

Knowledge, implicit knowledge and metaknowledge in visual agnosia and pure alexia.

Residual or implicit knowledge has been observed in patients with object agnosia, optic aphasia and pure alexia. Previous investigators have considered implicit knowledge in these patients to be dissociated from awareness on the basis of intact semantic capabilities that are consistent with right hemisphere processing. The absence of explicit verbal identification is presumably dependent upon damaged left hemisphere systems. We describe a 72-year-old woman with a left occipital infarction, object agnosia and pure alexia who was unable to explicitly identify visual stimuli (objects and words), but was able to make reliable judgements of her residual knowledge on forced-choice matching tasks. While the patient could not consistently demonstrate awareness of knowledge prior to stimulus matching ('Do you know what this is?'), she was able to reliably demonstrate awareness of knowledge for response accuracy ('Are you sure?') assessed after stimulus matching. Further, the extent of the patient's metaknowledge corresponded to her degree of preserved knowledge. We propose that this pattern of performance suggests limited or partial access to preserved semantic knowledge which, though degraded, is not 'non-conscious'.

Aged↗
PubMed1983

The anatomic basis of pure alexia.

The behavioral and anatomic correlates of pure alexia were analyzed in 16 patients. Right homonymous hemianopia failed to appear in three patients, who had right achromatopsia instead. Color anomia and unilateral optic ataxia were seen in six patients. Memory defects were found in two patients. Visual agnosia was noted in two. No patient had visual disorientation. The crucial anatomic correlate of alexia was a lesion of the paraventricular white matter of the left occipital lobe, capable of compromising both interhemispheric and intrahemispheric visual pathways. The lesion associated with color anomia was in the mesial occipitotemporal junction of the left hemisphere.

Adolescent↗
PubMed1988

Pure alexia in Japanese and agraphia without alexia in kanji. The ability dissociation between reading and writing in kanji vs kana.

A 60-year-old right-handed Japanese man with infarction of the left occipital lobe and inferior temporal gyrus initially showed pure alexia in kana and kanji. Later, though pure alexia in kana persisted, his kanji reading improved markedly, but with little improvement of kanji writing. We speculate that different pathways are involved in kanji reading and writing. Wernicke's area and its surrounding left middle temporal lobe might play the most important role for kanji reading when visual information is transmitted by any pathway. The pathway from Wernicke's area to the left occipital lobe via the middle and inferior temporal pathway may be indispensable for kanji writing. We postulate "agraphia without alexia in kanji" due to left inferior temporal subcortical damage.

Agraphia↗
PubMedDate not supplied

[Reading numbers in pure alexia: effects of the task and hemispheric specialization].

Selective conservation of the ability to read Arabic numbers in patients unable to read words or even letters is a classical characteristic of pure alexia described by Dejerine (1982). We report our work on the capacity of two patients with pure typical alexia to process numbers. Our main finding was that these patients could count pairs of Arabic numbers correctly when the reading task was simple (example 2 4-->"two four") or when the task involved comparing sizes (example 2 4-->"four is bigger than two"). Inversely, these patients often made mistakes when asked to perform arithmetic operations (example 2 4-->"two plus four equals six"). Using these two numbers, there was a similar dissociation between excellent performance on comparison tests and severe deficiency in reading out loud. We interpret these findings with the hypothesis that both of the hemispheres can identify Arabic numbers, but that the visual systems on the right and left play a different role during different tasks. In pure alexia, a lesion in the left identification system leads to selective deficiency in linguistic tasks such as reading numbers out loud, recognizing numbers with several figures or mental arithmetic. The right identification system in intact and is sufficient for comparison or reading isolated Arabic numbers.

Aged↗
PubMed2006

Patterns of peripheral paralexia: pure alexia and the forgotten visual dyslexia?

The concept of visual dyslexia put forward by Marshall and Newcombe (1973) is assessed. After a long period of neglect it was resurrected in the late 1990s in a narrow form. In the current paper it is proposed that a wider form of the functional syndrome is useful to include amongst other conditions attentional dyslexia and neglect dyslexia. The variety of sub-forms would correspond to the behavioural effects of the different ways in which the orthographic processing systems can be impaired. What distinguishes the broader form from pure alexia is that the patient lacks the capacity to use a serial letter processing strategy, and so interpretation of visual dyslexia in terms of the impairment to the orthographic processing systems is not contaminated by the use of a compensatory strategy that results in processing operations which are qualitatively very different from the normal and highly opaque. The lack of a serial letter processing strategy makes visual dyslexia a much more transparent functional syndrome.

Alexia, Pure↗
PubMed1998

Evolution of a form of pure alexia without agraphia in a child sustaining occipital lobe infarction at 2 1/2 years.

The progress of cognitive visual dysfunction over an 8-year period of a child who sustained bilateral occipital-lobe infarctions at the age of 2 1/2 years is described. She survived with normal intelligence and went on to attend mainstream school. She manifested many features of cognitive visual impairment and, in particular, developed a form of pure alexia without agraphia. She achieved some letter-by-letter reading but no sight vocabulary development, including to her own name. She learned to write imaginatively employing phonetically true spelling but cannot read what she has written. Her progress and the difficulties encountered during the management of her condition are discussed in this first case report of the evolution of pure alexia without agraphia in childhood. The features of this syndrome in the developing child who has never developed the capacity to read are contrasted with that seen in affected adults.

Agraphia↗
PubMed1988

"Pure alexia" without hemianopia or colour anomia.

We report a case of "pure alexia" without hemianopia or colour anomia, caused by a small subcortical haematoma in the dorso-lateral part of the occipital lobe, not affecting the splenium of the corpus callosum. It is argued that the reading disorder was due to a visual-verbal disconnection in spite of the fact that this typically is caused by a lesion in the medial part of the left occipital lobe including the splenium.

Aged↗
PubMed1989

[A case of multiple sclerosis with pure alexia].

We report here a case of multiple sclerosis (MS) showing pure alexia. The patient was a 28 year-old, right-handed male student of medicine. He had been healthy prior to college, but when he tried to read the newspaper one morning in January of 1983, he suddenly became aware that he could not. He could speak fluently and had no disturbances of auditory comprehension. No signs of abnormality were noted in his writing ability. Thereafter, the patient occasionally experienced difficulty in reading, together with right homonymous hemianopsia. These symptoms, however, usually vanished following sleep. In April, 1984, the patient experienced headache and ataxia when walking, followed by repeated remission and exacerbation of the symptoms. Corticosteroid therapy produced complete disappearance of the headache and ataxia. In September of 1985, he was hospitalized at our department due to the clouding of consciousness accompanied by convulsions. Neurologically, no abnormalities of the ocular fundus were noted and Babinski's sign was negative, but left hemiplegia was observed. Neuropsychologically, his intelligence was normal and he had no difficulty in writing, but paralexia was noted. There were no disorders of spontaneous speech or auditory comprehension. Examination by CT scan and magnetic resonance imaging revealed a number of lesions in the white substance of the cerebrum, including the left occipital lobe. The abnormal signs seen radiographically vanished when cortical hormones were administered. It has been thought that the symptoms of multiple sclerosis are due mainly to disorders of the white substance, and that MS seldom produces symptoms of aphasia, due to the fact that the lesions in this disease are generally small.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1997

[Pure alexia: presentation of three cases and review of the literature].

INTRODUCTION: Pure alexia is a syndrome characterized by the inability to read aloud in the absence of agraphia or apnasia. CLINICAL CASES: Three clinical cases showing this syndrome are presented. Case I had a left occipital lesion compatible with a subacute haematoma. He had problems with reading, visuo-spatial recognition, digital gnosia and memorizing texts. One year later there was considerable improvement in most of the sub-tests evaluated. There was still deficient colour naming right/left orientation and understanding of letters and words. Case 2 presented with a right homonymous hemianopia and slight left paresis. He had a small left occipital ischaemic infarct. One year later there was improvement on testing, with some deficit still in visual recognition, naming colours and memory. Case 3 presented with right homonymous hemianopia, slight right paresis and a left occipito-parietal expansive lesion. He had defective reading, choosing and naming of colours, right/left orientation and memory. On later evaluation, considerable improvement was seen. There was still colour agnosia, although less severe and mild 'laziness' of the right side. CONCLUSIONS: In the review of the literature, the disorder and the contributions of various authors, from Déperine in 1892 to the present day, are considered in detail.

Aged↗
PubMed1994

Pure alexia without agraphia: a classical cortical syndrome revisited.

A patient who developed pure alexia without agraphia following a stroke is described. An infarction of the left occipital pole was demonstrated by Magnetic Resonance Imaging (MRI). The literature on this rare syndrome is reviewed, and the localisation of damage in relation to the clinical findings discussed.

Agraphia↗
PubMed2001

Pure alexia from a posterior occipital lesion.

The authors report a patient with pure alexia (letter-by-letter reading) selectively impaired for kana (Japanese phonograms), cerebral achromatopsia, and right lower quadrantanopsia after hemorrhage in the left posterior occipital lobe, mainly under the lateral occipital gyri. The patient also could not recognize some single-character kana, nor could he discriminate between two shapes of a similar size. The authors believe that the posterior occipital lobe, including the lateral occipital gyri, is specialized to recognize kana characters in this patient.

Aged↗
PubMed1983

[Remarks on the "pure alexia" syndrome--a case report].

The article describes a case with the "pure alexia" syndrome caused by an infarct of the arteria cerebri posterior sinistra during a diffuse cerebral vascular disease. The authors consider the alexia to be a consequence of difficulties in transcoding graphic into graphemic structures.

Aged↗