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PubMed1981

Neurolinguistic analysis of the language abilities of a patient with a "double disconnection syndrome": a case of subangular alexia in the presence of mixed transcortical aphasia.

In contrast to the classic form of alexia without agraphia, subangular alexia results from a single lesion located deep in the white matter of the left parietal lobe. In the present report, a patient with subangular alexia and features of mixed transcortical aphasia is described. Neurolinguistic findings include: alexia without agraphia, paucity of spontaneous speech, moderate auditory comprehension difficulty, excellent repetition, echopraxia, colour agnosia, and naming disorder. Neurolinguistic tests revealed intact phonological organisation and grammatical filter." Our studies revealed a "double disconnection syndrome," the co-existence of two relatively rare neurobehavioural disorders. Furthermore, the studies reported here clearly show dissociations of language functions in both the visual and auditory modality, which demonstrates that the stages of language processing are separable.

Aphasia↗
PubMed2005

Acquired surface alexia in Spanish: a case report.

This paper reports a case study of acquired surface alexia in Spanish and discusses the most suitable tests to detect this syndrome in a writing system that is very regular for reading at the segmental and supra-segmental levels. Patient MM has surface alexia characterized by quantitatively good performance in reading words and pseudowords; accurate but slow and syllabic reading of words, nonwords and sentences; good performance in lexical decision tasks including words and nonwords; errors in lexical decision with pseudohomophones; and homophone confusions. This pattern of reading can be interpreted as a disorder in the lexical reading route and overdependence on the non-lexical route. We discuss nonlexical impairments and the interpretation of alexia and suggest tasks to identify surface alexia in a shallow orthography.

Brain Injuries↗
PubMed2006

Large acute cerebral hemorrhage presenting with pure alexia.

Alexia (the acquired inability to read) is an uncommon presenting complaint in the emergency department (ED). It is usually associated with a lesion in the brain located within the dominant hemisphere near the parieto-occipital junction, with some involvement of the splenium of the corpus callosum. Our review of the literature revealed multiple distinct causes for the finding of alexia, and a majority of the cases uncovered also involved agraphia (the acquired inability to write) and frequently visual field defects. We present the case of an otherwise healthy 35-year-old white man who arrived at our ED with the chief complaint of having difficulty reading. He was, however, able to write, and he exhibited no defects in his visual fields on gross testing in our ED. The patient was found to have a large, acute, intraparenchymal hemorrhage in the right posterior/inferior parietal cortex, very near the occipital lobe. We present this case, followed by a brief discussion, to heighten awareness of the complaint of alexia with or without agraphia as a possible presenting symptom of intracranial hemorrhage, or ischemic cerebrovascular accident.

Adult↗
PubMed1982

Conduction aphasia, syntactic alexia, and the anatomy of syntactic comprehension.

Syntactic alexia is the inability to comprehend graphically presented sentences when the meaning depends on syntax. Although previously described in association with Broca's aphasia and attributed solely to the frontal lobe portion of the lesions, syntactic alexia has not been reported to accompany conduction aphasia. We studied three patients who had conduction aphasia from temporoparietal lesions and syntactic alexia. None of them had lesions in Broca's area. Broca's aphasics and our patients with conduction aphasia have a syntactic comprehension disturbance. Since Broca's aphasics and our patients have lesions that may extend into the supramarginal gyrus, we postulate that this area may be critical for comprehending syntax.

Aphasia↗
PubMed2000

Rapid word identification in pure alexia is lexical but not semantic.

Following the notion that patients with pure alexia have access to two distinct reading strategies-letter-by-letter reading and semantic reading-a training program was devised to facilitate reading via semantics in a patient with pure alexia. Training utilized brief stimulus presentations and required category judgments rather than explicit word identification. The training was successful for trained words, but generalized poorly to untrained words. Additional studies involving oral reading of nouns and of functors also resulted in improved reading of trained words. Pseudowords could not be trained to criterion. The results suggest that improved reading can be achieved in pure alexia by pairing rapidly presented words with feedback. Focusing on semantic processing is not essential to this process. It is proposed that the training strengthens connections between the output of visual processing and preexisting orthographic representations.

Dyslexia↗
PubMed2000

Visuographemic alexia: a new form of a peripheral acquired dyslexia.

We report a single-case study of peripherally acquired dyslexia that meets the clinical criteria of "alexia without agraphia." The patient, AA, has a large infarct involving the left posterior cerebral artery. The most striking feature is a severe impairment in recognizing single visually presented letters that precludes explicit or implicit access to reading, even in a letter-by-letter fashion. AA can, however, differentiate letters from similar nonsense characters and digits, and he is also able to identify alphanumeric signs when the visual channel is bypassed (through somesthesic or kinesthesic presentation). Spelling tasks are also well performed. Since there is a breakdown in mapping a visually presented letter to its abstract graphemic representation, we propose the term "visuographemic alexia" for this kind of reading disorder. The pattern of deficits is interpreted following theoretical models previously developed in cognitive neuropsychology. An alexia for arabic numerals with preserved comprehension lends additional support for the crucial processing of different notational systems (e.g., phonographic vs logographic). More general perceptive disorders do not seem to account for these patterns; they are material-specific. Finally, we attempt to specify functional correlations with the implied neural networks.

Dominance, Cerebral↗
PubMed1978

Paroxysmal alexia.

This report describes a case of paroxysmal alexia which progressed to a persistent syndrome of alexia without agraphia. The sequence of symptoms beginning with a sensation of eyeball movement followed by blurred vision in the affected eye, alexia and diminished awareness strongly implicates an ictal mechanism. Anatomical, physiological and psychological considerations suggest that the syndrome arose from functional disruption between the visual cortex and the dominant inferior parietal cortex.

Brain Neoplasms↗
PubMed1979

Recovery from alexia without agraphia: report of an autopsy.

The patient is a 58-year-old Japanese teacher of German literature who suffered twice from cerebrovascular accidents, showing alexia without agraphia. Pathological examination showed an old infarct in the posterior two-thirds of the fusiform and almost the whole lingual gyrus, involving the posterior border of the parahippocampal gyrus in the left hemisphere. The left cuneus and the calcarine cortex were preserved. There was degeneration of the lower third of the splenium of the corpus callosum, extending to its occipital radiation and tapetum on both sides. Comparing clinico-pathological findings of the 31 known autopsy cases, it was proposed that the lesion of the left spleno-lingual system produces alexia without agraphia but it may ameliorate. In addition, when spleno-cuneate system is also involved alexia becomes persistent and it may accompany object agnosia or optic aphasia.

Agraphia↗
PubMed1998

Visual complexity in letter-by-letter reading: "pure" alexia is not pure.

Standard accounts of pure alexia have favoured the view that this acquired disorder of reading arises from damage to a left posterior occipital cortex mechanism dedicated to the processing of alphanumeric symbols. We challenge these accounts in two experiments and demonstrate that patients with this reading deficit are also impaired at object identification. In the first experiment, we show that a single subject, EL, who shows all the hallmark features of pure alexia, is impaired at picture identification across a large set of stimuli. As the visual complexity of pictures increases, so EL's reaction time to identify the stimuli increases disproportionately relative to the control subjects. In the second experiment, we confirm these findings with a larger group of five pure alexic patients using a selected subset of high- and low-visual complexity pictures. These findings suggest that the deficit giving rise to pure alexia is not restricted to orthographic symbols per se but, rather, is a consequence of damage to a more general-purpose visual processing mechanism.

Adult↗
PubMed1998

Treatment of a case of phonological alexia with agraphia using the Auditory Discrimination in Depth (ADD) program.

Phonological alexia and agraphia are acquired disorders characterized by an impaired ability to convert graphemes to phonemes (alexia) or phonemes to graphemes (agraphia). These disorders result in phonological errors typified by adding, omitting, shifting, or repeating phonemes in words during reading or graphemes when spelling. In developmental dyslexia, similar phonological errors are believed to result from deficient phonological awareness, an oral language skill that manifests itself in the ability to notice, think about, or manipulate the individual sounds in words. The Auditory Discrimination in Depth (ADD) program has been reported to train phonological awareness in developmental dyslexia and dysgraphia. We used a multiple-probe design to evaluate the ADD program's effectiveness with a patient with a mild phonological alexia and mixed agraphia following a left hemisphere infarction. Large gains in phonological awareness, reading and spelling nonwords, and reading and spelling real words were demonstrated. A follow-up reassessment, 2 months posttreatment, found the patient had maintained treatment gains in phonological awareness and reading, and attained additional improvement in real word reading.

Agraphia↗
PubMed1977

Does alexia without agraphia always include hemianopsia?

A patient with alexia without agraphia (pure alexia) is reported. Bedside examination of the visual fields disclosed no abnormalities; but perimetric examination demonstrated an incomplete right homonymous hemianopsia with some sparing of the peripheral part of the visual field. The literature on pure alexia without hemianopsia is reviewed and it is concluded that this syndrome has hardly been described with certainity.

Dyslexia, Acquired↗
PubMed1986

Dynamic spelling alexia.

A 59-year-old, right-handed, college-educated male examined after stroke presented spelling alexia with relative sparing of writing. He was not aphasic. A striking feature of the alexia was preserved recognition of letters printed in view by the clinician. He was able to read words through letter-by-letter oral spelling when letters were presented in this dynamic fashion. We describe this as a dynamic form of spelling alexia. Head CT scan showed a large left hemisphere posterior lesion infringing on the corpus callosum, and a right hemisphere opercular lesion. We suggest that sparing of the right parietal-occipital cortex may contribute to the remarkable sparing of dynamic letter reading.

Cerebral Cortex↗
PubMed2002

Kinesthetic alexia due to left parietal lobe lesions.

To investigate the neuropsychological mechanisms of kinesthetic alexia, we asked 7 patients who showed kinesthetic alexia with preserved visual reading after damage to the left parietal region to perform tasks consisting of kinesthetic written reproduction (writing down the same letter as the kinesthetic stimulus), kinesthetic reading aloud, visual written reproduction (copying letters), and visual reading aloud of hiragana (Japanese phonograms). We compared the performance in these tasks and the lesion sites in each patient. The results suggested that deficits in any one of the following functions might cause kinesthetic alexia: (1) the retrieval of kinesthetic images (motor engrams) of characters from kinesthetic stimuli, (2) kinesthetic images themselves, (3) access to cross-modal association from kinesthetic images, and (4) cross-modal association itself (retrieval of auditory and visual images from kinesthetic images of characters). Each of these factors seemed to be related to different lesion sites in the left parietal lobe.

Aged↗
PubMedDate not supplied

Transtentorial herniation with posterior cerebral artery territory infarction. A new mechanism of the syndrome of alexia without agraphia.

A 39-year-old male developed a right homonymous hemianopsia and alexia without agraphia following emergency surgery for hemorrhage into a left frontal tumor. A computerized tomographic (CT) scan demonstrated low density areas in the left frontal region and in the territory of the left posterior cerebral artery. The alexia without agraphia syndrome appeared to result from compression of the left posterior cerebral artery by a transtentorial pressure cone, a mechanism not previously reported in this syndrome. The behavioral investigation confirmed the diagnosis and replicated recent findings related to the syndrome of alexia without agraphia.

Adult↗
PubMed1979

Alexia without agraphia: lateral and medial infarction of left occipital lobe.

Four cases of alexia without agraphia were studied by 99m-technetium pertechnetate brain scan. Two types of increased uptake were seen. One was of the triangular type near the midline in the posterior view, said to characterize an infarction in the distribution area of the posterior cerebral artery. This was associated with the well-known clinical picture of alexia without agraphia accompanied by hemianopia and color-naming defect, and was confirmed by postmortem examination. The other type of pathologic isotope uptake, observed in three patients, was more laterally placed, in the basal part of the left occipital lobe, and did not reach the midline. In these cases the alexia was transient and not associated with color-naming defects.

Adult↗
PubMed1982

Right thalamic injury, impaired visuospatial perception, and alexia.

In pure alexia, acquired inability to read contrasts with normal speech and handwriting. Rare cases of right hemisphere lesions causing this syndrome are usually attributed to right hemisphere dominance for language. After infarction of the right occipital lobe and thalamus, a fully right-handed man became alexia, but language and spontaneous and dictated writing were intact. Left hemispatial neglect and constructional disturbances were marked, and we suggest that pure alexia was mimicked by the impairment in visuospatial perception. Injury of the nondominant hemisphere and thalamus together may have been important in causing these deficits.

Cerebral Infarction↗
PubMed1998

Progressive ventral posterior cortical degeneration presenting as alexia for music and words.

Patients with posterior cortical atrophy may have dorsal visual system (occipital-parietal) dysfunction (optic ataxia, visuospatial disorientation, and simultanagnosia), ventral visual system (occipital-temporal) dysfunction (pure alexia, prosopagnosia, visual anomia, and agnosia), or both. We report a professional musician with ventral system dysfunction whose first symptom was alexia for music. Subsequently, she developed pure alexia for words but had preserved sorting of words. These observations suggest that the ventral visual system is important in music and word reading. However, sorting of words may be mediated by the dorsal visual system.

Aged↗
PubMed1979

Alexia without agraphia in a musician after transcallosal removal of a left intraventricular meningioma.

After a meningioma situated in the trigone of the left lateral ventricle was excised by the transcallosal approach of Kempe and Blaylock, a right-handed musician with a right hemianopsia developed alexia without agraphia. In contrast to previously reported cases of this syndrome arising from other etiologies, he was unable to read single letters or numbers. Neuropsychological studies at 42 and 126 days after operation also disclosed an inability to associate auditory or tactile stimuli with visually perceived material, whereas speech and verbal comprehension were intact. Although the alexia extended to musical notes, he could interpret other musical symbols (e.g., treble clef). Appreciation of rhythm and expressive musical ability were relatively preserved, although judgment of other musical features (including discrimination of pitch, duration, and loudness) was compromised. The findings suggest that alexia may occur as a consequence of the transcallosal procedure when a right hemianopsia is present. However, other linguistic abilities may be better preserved by the transcallosal approach to the ventricle than by a transcortical operation.

Agraphia↗