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At least 451 records · Page 25Linked to original sources
PubMed1981

Phonological agraphia and the lexical route in writing.

A new agraphia syndrome is described in which the patient can write certain classes of words virtually perfectly but is very poor at writing non-words. It is shown that this difficulty cannot be explained by perceptual or memory problems. A number of aspects of the syndrome are shown to correspond to those of phonological alexia within the acquired dyslexias. It thus appears that agraphia syndromes can be analysed by methods analogous to those recently developed for the study of the acquired dyslexias.

Agraphia↗
PubMed1982

Aphasia in a prelingually deaf woman.

A left parietal infarct in a prelingually deaf person resulted in an aphasia for both American Sign Language (ASL) and written and finger-spelled English. Originally the patient had a nearly global aphasia affecting all language systems. By five to seven weeks post-onset her symptoms resembled those of hearing aphasics with posterior lesions: fluent but paraphasic signing, anomia, impaired comprehension and repetition, alexia, and agraphia with elements of neologistic jargon. In addition, there was a pronounced sequential movement copying disorder, reduced short-term verbal memory and acalculia. In general, the patient's sign errors showed a consistent disruption in the structure of ASL signs which parallels the speech errors of oral aphasic patients. We conclude that most aphasic symptoms are not modality-dependent, but rather reflect a disruption of linguistic processes common to all human languages. This case confirms the importance of the left hemisphere in the processing of sign language. Furthermore, the results indicate that the left supramarginal and angular gyri are necessary substrates for the comprehension of visual/gestural languages.

Aged↗
PubMed1991

A historic case of visual agnosia revisited after 40 years.

In one of the seminal works on visual agnosia, Adler (1944, 1950) presented the case of a 22-yr-old woman who sustained carbon monoxide cerebral toxicity in the Cocoanut Grove nightclub diaster of 1942. We located this patient 40 yrs after injury and performed a detailed reevaluation. The patient demonstrated persistent deficits in visual recognition, characterized most prominently by defective recognition of elemental shape and form, associated with alexia, prosopagnosia, visuospatial disorientation and impaired visual imagery. Visual acuity, colour recognition, writing ability and verbal intelligence were relatively preserved. Isolated bilateral occipital injury was demonstrated by CT and MRI scanning. On comparison with previously reported cases, our results support the hypothesis that carbon monoxide toxicity can induce a visual agnosia of the apperceptive type with well defined characteristics, seldom seen with other types of cerebral injury. Prognosis for long-term recovery is poor.

Accidents↗
PubMed1991

A specific deficit for numbers in a case of dense acalculia.

In this study we investigated the acalculic condition of a patient, C.G., with the classical signs of Gerstmann's Syndrome: finger agnosia; right-left disorientation; a profound agraphia (but with an equally profound alexia) and a remarkably dense acalculia. Using a series of number processing and number knowledge tasks, a selective impairment for numbers was demonstrated. Within the category of numbers C.G. showed a largely preserved ability to deal with numbers below 4, in all tasks and in all modalities, while she was totally unable to deal with numbers above 4. The consistency of responses and the ineffectiveness of cueing indicated that numbers above 4 were lost, rather than hard to access. Further testing showed that this impairment did not result from a more general semantic memory problem, a difficulty in understanding quantities or a deficit in reasoning abilities thought to underlie the concept of numbers. Difficulty with some other ordinal structures was also present, but appeared unrelated to those affecting numbers.

Female↗
PubMed1992

The topography of callosal reading pathways. A case-control analysis.

Lesion topography and reading ability were analysed in 17 patients with dominant posterior cerebral artery territory infarction. Patients with dominant posterior cerebral artery infarction in whom reading was unaffected served as an anatomical control group. Normal readers had lesions in the medial and ventral occipital lobe, sparing dorsal white matter pathways and the ventral temporal lobe. Global and permanent alexia occurred only with additional injury to the splenium, forceps major or white matter above the occipital horn of the lateral ventricle. These data suggest that callosal pathways mediating reading lie above the occipital horn and have little connection with the ventromedial occipital region. Patients with 'spelling dyslexia' had large lesions of the ventral temporal lobe involving cortical regions believed to participate in later stages of visual processing. These findings provide a framework for the prediction of dyslexia type and severity based on lesion topography.

Adult↗
PubMed1998

The variants of reading epilepsy. A clinical and video-EEG study of 17 patients with reading-induced seizures.

We present the clinical and electrographic data of 17 patients with reading-induced seizures documented with ictal video-EEG studies during provocation with language related tasks. The median age at onset was 15 years (range 11-22 years) and the male:female ratio was 2.4. Fourteen patients had no spontaneous seizures of any type while the remaining three had infrequent generalized tonic-clonic seizures during nocturnal sleep. Two distinct electroclinical ictal patterns were confirmed on video-EEG analysis. (i) Fifteen patients had reading-induced jerks which invariably involved the region of the jaw but also included the upper limbs in five of them. Ictal EEG discharges were noted in 12 patients; these were brief but varied in terms of morphology and spatial distribution, with a clear tendency for left-sided predominance. All but one of these patients had similar myoclonic seizures induced by linguistic activities other than reading, the phenomenon probably justifying the term 'language-induced epilepsy'. Some patients had evidence of transient cognitive impairment associated with the reading-induced jaw or limb jerks. Three patients had a sibling with reading epilepsy but there was no other family history of epileptic seizures. (ii) Two patients had reading-provoked paroxysmal alexia without motor symptoms, associated with prolonged focal ictal EEG abnormalities. Reading provoked a subclinical, continuous and reproducible EEG activation over the left posterior temporal area. We propose that ictogenesis in reading or language-induced epilepsy is based on the reflex activation of a hyperexcitable network that subserves the function of speech and extends over multiple cerebral areas on both hemispheres. The parts of this network responding to the stimulus may, secondarily, drive the relative motor areas producing the typical regional myoclonus. This network hyperexcitability can be genetically determined and its clinical expression is age-related.

Adolescent↗
PubMed2002

Late plasticity for language in a child's non-dominant hemisphere: a pre- and post-surgery fMRI study.

The ability of the right hemisphere to sustain the acquisition or the recovery of language after extensive damage to the left hemisphere has been essentially related to the age at the time of injury. Better language abilities are acquired when the insult occurs in early childhood (perinatal insults) compared with later occurrence. However, while previous studies have described the neuropsychological pattern of language development in typical cases, the neural bases of such plasticity remain unexplored. Non-invasive functional MRI (fMRI) is a unique tool to assess the neural correlates of brain plasticity through repeated studies, but the technique has not been widely used in children because of methodological limitations. Plasticity of language was studied in a boy who developed intractable epilepsy related to Rasmussen's syndrome of the left hemisphere at age 5 years 6 months, after normal language acquisition. The first fMRI study at age 6 years 10 months showed left lateralization of language networks during a word fluency task. After left hemispherotomy at age 9 years, the child experienced profound aphasia and alexia, with rapid recovery of receptive language but slower and incomplete recovery of expressive language and reading. Postoperative fMRI at age 10 years 6 months showed a shift of language-related networks to the right during expressive and receptive tasks. Right activation was seen mainly in regions that could not be detected preoperatively, but mirrored those previously found in the left hemisphere (inferior frontal, temporal and parietal cortex), suggesting reorganization in a pre-existing bilateral network. In addition, neuropsychological data of this case support the hypothesis of innately more bilateral distribution of receptive than expressive language. This first serial fMRI study illustrates the great plasticity of the child's brain and the ability of the right hemisphere to take over some expressive language functions, even at a relatively late age. It also suggests a limit for removal of the dominant hemisphere beyond the age of 6 years, a classical limit for the critical period of language acquisition.

Brain↗
PubMed2002

Language-specific tuning of visual cortex? Functional properties of the Visual Word Form Area.

The first steps in the process of reading a printed word belong to the domain of visual object perception. They culminate in a representation of letter strings as an ordered set of abstract letter identities, a representation known as the Visual Word Form (VWF). Brain lesions in patients with pure alexia and functional imaging data suggest that the VWF is subtended by a restricted patch of left-hemispheric fusiform cortex, which is reproducibly activated during reading. In order to determine whether the operation of this Visual Word Form Area (VWFA) depends exclusively on the visual features of stimuli, or is influenced by language-dependent parameters, brain activations induced by words, consonant strings and chequerboards were compared in normal subjects using functional MRI (fMRI). Stimuli were presented in the left or right visual hemifield. The VWFA was identified in both a blocked-design experiment and an event-related experiment as a left-hemispheric inferotemporal area showing a stronger activation to alphabetic strings than to chequerboards, and invariant for the spatial location of stimuli. In both experiments, stronger activations of the VWFA to words than to strings of consonants were observed. Considering that the VWFA is equally activated by real words and by readable pseudowords, this result demonstrates that the VWFA is initially plastic and becomes attuned to the orthographic regularities that constrain letter combination during the acquisition of literacy. Additionally, the use of split-field stimulation shed some light on the cerebral bases of the classical right visual field (RVF) advantage in reading. A left occipital extrastriate area was found to be activated by RVF letter strings more than by chequerboards, while no symmetrical region was observed in the right hemisphere. Moreover, activations in the precuneus and the left thalamus were observed when subjects were reading RVF versus left visual field (LVF) words, and are likely to reflect the attentional component of the RVF advantage.

Adult↗
PubMedDate not supplied

Functional segregation of color and motion processing in the human visual cortex: clinical evidence.

Anatomical and physiological investigations indicate two major distinct functional streams within the extrastriate visual cortex of the macaque monkey, and behavioral observations suggest that the ventral (occipitotemporal) pathway is the cornerstone for object recognition whereas the dorsal (occipitoparietal) pathway is primarily involved in visuospatial perception and visuomotor performance. In the context of this dichotomy we conducted a psychophysical and neuropsychological study of visual perceptual abilities in two stroke patients, each with lesions involving several extrastriate areas. Magnetic resonance imaging demonstrated bilateral lesions; in one patient (E.W.) the lesion involves the ventral medial portions of the occipital and temporal lobes, and in the other (A.F.) the lesion involves dorsally the occipital-parietal area, including the region of the temporal-parietal-occipital junction. E.W. suffers from achromatopsia of central origin, prosopagnosia, visual agnosia, and alexia without agraphia. His depth and motion perception, including recognition of moving objects, are normal. He has superior visual field loss bilaterally, and slightly impaired acuity, and complains that the world appears in a deep twilight even on a sunny day. In contrast, A.F. shows specific deficits of stereopsis, spatial localization, and several aspects of motion perception. He is also impaired at recognizing objects presented from unconventional views, but recognition of prototypical views of objects, and color and form discrimination are normal, as is his ability to recognize faces. The anatomical characteristics of the lesions of these two patients permit a direct experimental comparison of the effects of lesions confined to the parietal or temporal pathways. E.W.'s and A.F.'s performance on the psychophysical and neuropsychological tasks discussed here supports the functional distinction between a dorsal and a ventral extrastriate system but additionally suggests the existence of a pathway involved in identification-from-motion that is separate from both the dorsal early motion/spatial analysis pathway and the ventral color/static-form pathway.

Cerebrovascular Disorders↗
PubMed2000

Cerebral localization of the center for reading and writing music.

The mechanisms that underlie the ability to read and write music remain largely unclear compared to those involved in reading and writing language. We had the extremely rare opportunity to study the cerebral localization of the center for reading and writing music in the case of a professional trombonist. During rehearsal immediately before a concert, he suffered a hemorrhage that was localized to the left angular gyrus, the area that has long been known as the center for the ability to read and write. Detailed tests revealed that he showed symptoms of alexia with agraphia for both musical scores and language.

Agraphia↗
PubMed2005

Letter-by-letter acquired dyslexia is due to the serial encoding of letters.

Letter-by-letter acquired dyslexia (pure alexia) is assumed to be related to the serial encoding of letters, but the evidence for this assumption is somewhat indirect. Here, we demonstrate that the deficit is indeed due to serial encoding by comparing the performance of a letter-by-letter dyslexic reader with the performance of normal readers who were forced to read letter by letter; the data patterns are remarkably similar.

Dyslexia, Acquired↗
PubMed1996

Memory dysfunction in mild aphasics.

The effect of mild aphasia (n = 9), as a result of subarachnoid haemorrhage (SAH), was evaluated against one matched (sex, age, and education) control group suffering from SAH of unknown origin without aphasia, and against one matched healthy control group. According to aphasia testing (Reinvang & Engvik, 1980), criteria for a classical diagnosis were not met. Therefore, the patients were characterized as mild aphasics: They generally displayed intact audo-verbal comprehension and repetition abilities, and they demonstrated a fluent, spontaneous speech. However, they showed phonemic and semantic paraphasias, with self-corrections; a few patients displayed alexia and agraphia. Memory performance of these three groups was evaluated by a neuropsychological test battery, designed to tap various components of verbal memory function. From the results it was concluded that: (a) Short-term memory is impaired, as regards the phonological loop and the central executive in working memory, whereas maintenance rehearsal is unaffected, given that the demands on phonological coding is minimized, (b) long-term memory is also generally impaired, whereas long-term learning and forgetting by means of subject-performed tasks proceeds within a normal range. Impairments were hypothesized to reflect less efficient central executive functions of working memory, involving generation of less appropriate semantic codes and phonological representations, (c) mildly aphasic patients are not subjectively aware of their own memory deficits, and (d) aphasia classification by means of standard procedures do not sufficiently characterize the nature of a mildy aphasic patient's memory problems.

Adult↗
PubMed1987

Acquired crossed aphasia in a child.

A case is reported of acquired aphasia in a 15-year-old right-handed boy, secondary to a right occipitotemporal tumour. He had aphasia, alexia, agraphia and visuospatial disturbances, which persisted after partial removal of the neoplasm. 15 days after surgery he had an episode of left focal seizures, after which the aphasia worsened. One month later he developed severe (global) aphasia associated with rostral extension of the tumour. Although crossed aphasia was previously considered common in children, there are few reports with anatomical confirmation. In the authors' own series of 31 children with acquired aphasia this is the only case of crossed aphasia, an incidence similar to that found in adult cases.

Adolescent↗
PubMedDate not supplied

Paroxysmal aphasias.

Forty cases of paroxysmal aphasia were found in a sample of 4,000 patients with epilepsy. Twenty-five had structural brain damage demonstrated by CT scan. Except for two cases, the epileptic focus was located in the left hemisphere. Two patients had a paroxysmal alexia associated with the aphasic disorder. Though preliminary, our data suggest a correlation of dysphasic components with posterior lesions and phonatory components with anterior lesions.

Adolescent↗
PubMedDate not supplied

Parietal and occipital lobe epilepsy: a review.

There has been considerable recent interest in frontal lobe epileptic syndromes, and less attention paid to occipital and parietal epilepsies. The occipital and parietal lobes have arbitrary anatomical borders. The prinicpal seizure symptomatology includes somatosensory (paresthetic, painful, thermal, sexual, apraxia, disturbances of body image); visual (amaurotic, elementary and complex hallucinations, illusions) and other phenomena (anosognosia, apraxia, acalculia, alexia, aphemia, confusional states, gustatory, vertiginous, adversive, oculoclonic and eyelid flutter). The seizure symptoms are of varying localizing and lateralizing value and seizure discharges may spread rapidly and perceived symptoms may reflect secondary spread rather than the primary site of seizure onset. Recognized parietal and occipital epilepsy syndromes include benign epilepsy of childhood with centrotemporal spikes, benign epilepsy of childhood with parietal evoked spikes, benign occipital epilepsy of childhood, migraine/epilepsy syndromes, and epilepsy with bilateral occipital calcification. In addition, occipital and parietal epilepsy may be on the basis of any underlying structural lesion. There is frequently a poor correlation between clinical and EEG features. MRI and functional imaging often reveals underlying pathology. There have been no specific trials of different antiepileptic drugs for occipital and parietal seizures. Surgical treatment has its place, with attention to the risk of causing a fixed neurological deficit.

Electroencephalography↗
PubMed2001

Clinical and magnetic resonance imaging regression of progressive multifocal leukoencephalopathy in an AIDS patient after intensive antiretroviral therapy.

A 36-year-old homosexual man with 6 months of visual symptoms and headaches had right homonymous hemianopia, mild new learning impairment, and alexia with agraphia. The initial brain magnetic resonance imaging (MRI) scan was reported consistent with left occipital infarction. Subsequent MRI demonstrated abnormal demyelination in subcortical white matter and deep parieto-occipital white matter bilaterally, but primarily left. Human immunodeficiency virus testing and cerebrospinal fluid polymerase chain reaction for JC virus DNA were both positive, consistent with progressive multifocal leukoencephalopathy (PML) with AIDS. His clinical status steadily deteriorated, and MRI white matter abnormalities worsened despite high-dose antiretroviral therapy. After the antiretroviral regimen was intensified by the addition of a protease inhibitor, rapid clinical and radiographic improvement occurred with subsequent MRI studies revealing only residual left parieto-occipital encephalomalacia. PML in AIDS patients has been associated with a nearly uniformly poor prognosis until recent reports of improved outcomes after highly active antiretroviral therapy. This patient with PML and AIDS similarly showed a robust clinical and MRI response to intensive antiretroviral combination therapy, which has been maintained for more than 3 years.

AIDS-Related Opportunistic Infections↗
PubMed1988

Maurice Ravel's illness: a tragedy of lost creativity.

Maurice Ravel had been subject to psychiatric disorder for many years when signs of organic brain disease appeared at the age of 52. Aphasia, apraxia, agraphia, and alexia became established some five years later. Musical creativity was lost. Alajouanine diagnosed cerebral atrophy with bilateral ventricular enlargement. Though Ravel's condition deteriorated progressively, generalised dementia was not apparent. He died in December 1937, after a craniotomy performed by Clovis Vincent, possibly from a subdural haematoma. Vincent's operative findings are described here. The likely cause of Ravel's illness was a restricted form of cerebral degeneration.

Famous Persons↗
PubMed1978

Dissociated disorders of speaking and writing in aphasia.

Of 500 left brain-damaged patients with educational level above elementary school investigated with a standard quantitative battery for dissociation between oral and written expression, speech was found to be selectively impaired in seven (three with "pure anarthria," two with anarthria in the context of Broca's aphasia, and two with fluent aphasia with remarkable sparing of writing), and writing in another seven (two with "pure" agraphia, two with "agraphia with mild alexia," and three with "agraphia with mild fluent aphasia.") The nature of three conditions (pure anarthria, fluent aphasia with sparing of writing, and pure agraphia) is discussed, with evidence of a selective association between pure agraphia and lesions of the upper left parietal lobule.

Adult↗