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Biomedical subjects

D N Levine

Publications and source records attributed to D N Levine.

At least 37 records · Page 2Linked to original sources
PubMed1986

Covariant defects in visuospatial abilities and recall of verbal narrative after right hemisphere stroke.

Eighteen patients with right hemisphere strokes and 10 age-matched normal controls were tested for visuospatial abilities and for recall of brief narrative passages. Visuospatial and verbal abilities were evaluated using an objective scoring protocol that quantified accuracy in reproducing individual details, appreciation of structural relationships, and the appearance of unwarranted intrusions. The right hemisphere damaged group was found to be impaired on all measures of verbal recall. Across subjects these defects, particularly the inability to abstract information from the narrative passages, correlated with the degree of constructional apraxia. Analysis of CT scans failed to define a discrete region of the right hemisphere selectively associated with either the visuospatial or verbal defects, but indicated that both are exacerbated by the presence of premorbid brain atrophy.

Aged↗
PubMed1986

Left spatial neglect: effects of lesion size and premorbid brain atrophy on severity and recovery following right cerebral infarction.

We measured the severity of left spatial neglect in 29 patients, 2 to 4 weeks after right cerebral infarction. The severity of neglect increased with both the size of the lesion and the degree of premorbid diffuse cortical atrophy. Recovery over 3 to 5 months from an initially moderate to severe neglect was less complete in patients with cortical atrophy. The importance of lesion size shows that spared areas of the right hemisphere limit the severity and duration of left neglect. The importance of premorbid atrophy suggests that the integrity of the left hemisphere is also essential.

Adult↗
PubMed1986

Opticosensory ataxia and alien hand syndrome after posterior cerebral artery territory infarction.

A right-handed woman developed left homonymous hemianopia and left hemianesthesia from infarction due to right posterior cerebral artery occlusion. Ataxia of the left arm and leg was severe and was not improved by vision. The patient often interpreted spontaneous movements of the left arm as alien in origin. The ataxia may have been caused by a combination of sensory ataxia, resulting from right thalamic infarction, and crossed-optic ataxia, resulting from posterior disconnection of the hemispheres due to right temporo-occipital infarction. This opticosensory ataxia was associated with a new form of "alien hand" syndrome.

Aged↗
PubMed1985

Dementia after surgery for cerebellar stroke: an unrecognized complication of acute hydrocephalus?

Three patients became demented after surgery for cerebellar hemorrhage or infarction with acute hydrocephalus. All were inattentive, perseverative, and disoriented. They had difficulty with memory, and trouble solving arithmetic problems or copying geometric figures. None showed aphasia, apraxia, or agnosia, although one had word-finding difficulty. One improved substantially in 6 months; one improved slightly in 1 year, and one did not change. None had persistent hydrocephalus. Acute hydrocephalus may have damaged the periventricular white matter to cause the dementia.

Aged↗
PubMed1985

MRI and the study of aphasia.

Three-dimensional magnetic resonance imaging (MRI) was used to study various aphasia and neurobehavioral syndromes due to embolic or thrombotic cerebral infarction. Two patients are presented to illustrate how MRI may complement, and sometimes improve on, CT for the in vivo demonstration of anatomic changes underlying said syndromes. MRI images were reconstructed at planes selected to match CT, and at coronal planes through the entire anteroposterior extent of the lesions. Both CT and MRI detected lesions; however, MRI provided better differentiation of gray and white matter. Coronal reconstructions aid in optimally visualizing the relationship of lesions to the opercular and perisylvian gyri. CT may be inadequate to define actual extent of lesions, whereas MRI may more clearly show that apparently subcortical lesions can, in fact, involve the cortex as well.

Adult↗
PubMed1985

Two visual systems in mental imagery: dissociation of "what" and "where" in imagery disorders due to bilateral posterior cerebral lesions.

We studied two patients with impaired visual perception and imagery caused by bilateral posterior cerebral lesions. The first had prosopagnosia and achromatopsia, and the imagery disorder involved the description of objects from memory, especially faces and animals, and colors of objects. The second had visual disorientation; the imagery problem involved the description of spatial relations from memory. Impairments of visual imagery, like disorders of visual perception, can be dissociated. Object and color imagery may be dissociated from imagery for spatial relations. A given imagery deficit tends to be associated with the corresponding type of perceptual deficit.

Adolescent↗
PubMed1984

Crossed Wernicke's aphasia.

Severe Wernicke's aphasia occurred suddenly in a right-handed man and persisted with little improvement until he died 54 days later. Postmortem examination showed an infarct in the posterior temporoparietal region of the right hemisphere. This case demonstrates two new features of crossed dextral aphasia. First, language skills may be fully lateralized to the right hemisphere in right-handed patients. Second, when crossed lateralization occurs, the usual localization of aphasic syndromes is common, suggesting that the intrahemispheric organization mediating language activities is the same in the right hemisphere of the crossed dextral and the left hemisphere of the typical right-handed individual.

Aged↗
PubMed1984

The anatomic basis of delusions after right cerebral infarction.

We studied the nature and causes of delusions after infarction of the right cerebral hemisphere. Delusions involved orientation in time and place, events in the recent past, and the identities of familiar individuals. Some were transient and disorganized, and others were more fixed. No particular site in the right hemisphere was associated with particular delusions. The different delusions may be varied manifestations of a basic disorder of thought and memory. The major determinant of the delusions was cerebral atrophy. Age, location, and size of lesion had no major effect. The superimposition of a new right hemisphere lesion on a diffusely atrophied brain seems to cause delusions that can be expressed verbally because the left hemisphere is relatively preserved.

Aged↗
PubMed1982

Language in the absence of inner speech.

A 54-year-old man abruptly became mute with mild right hemiparesis. Written expression, comprehension of speech and print, calculating ability, and verbal short-term recall, although slow, were largely preserved. Extensive studies demonstrated complete loss of inner speech. He was unable to speak to himself and unable to appreciate the phonological structure of words. Instead, his preserved language skills were based on a highly developed visual imagery. This case greatly extends the range of language skills previously thought possible in individuals who suffer the loss of inner speech.

Aphasia↗
PubMed1982

Delayed psychosis after right temporoparietal stroke or trauma: relation to epilepsy.

We observed acute onset of delayed psychosis in 8 patients 1 month to 11 years after right temporoparietooccipital (TPO) stroke or trauma. The psychotic disorder included hallucinations and, in some patients delusions and agitation. All patients had spatioconstructional difficulties. None had an earlier psychiatric disorder. Seven of eight patients had clinical seizures, often in close temporal relationship to the psychosis. The pathophysiology of the psychosis may be related to that of the epilepsy.

Adult↗
PubMed1981

Acquired learning disability for reading after left temporal lobe damage in childhood.

A 6-year-old boy developed hemorrhage in the left temporal lobe and subsequently underwent left temporal lobectomy. Afterwards, he was completely unable to learn to read or write. Psychological tests showed impairment in verbal learning and memory, with right ear and right visual field superiority in verbal perception. A Wada test showed no aphasia after right carotid injection. We conclude that damage to the speech-dominant temporal lobe resulted in the inability to learn to read or write. Despite the lesion, speech remained strongly lateralized to the left hemisphere, accounting for the right-sided advantage in verbal perception. Some patients with developmental dyslexia may have dysfunction of a strongly dominant left hemisphere rather than a delay or incompleteness of language lateralization.

Adult↗
PubMed1981

Acute quadriplegia due to bilateral cerebral metastases.

A 51-year-old man developed severe quadriparesis without sensory loss after a fall on the occiput. When he was treated with corticosteroids, the weakness worsened slightly for 2 days, but he then progressively improved and ultimately walked unassisted. Two months later, postmortem examination disclosed metastatic tumors in the superior portion of each precentral gyrus. The subjacent white matter was edematous. No spinal cord abnormalities were found. The clinical, radiologic, and neuropathologic findings suggest that the quadriplegia resulted from these bilateral cerebral lesions and not from spinal cord dysfunction. The rapid development of cerebral edema, perhaps precipitated by trauma, seemed to account for the acute onset of symptoms in this case.

Brain Edema↗
PubMed1980

Visual discrimination after lesion of the posterior corpus callosum.

Visual discrimination was studied in each visual field of a patient with surgical section of the posterior corpus callosum. Light-detection thresholds were increased nearly equally in right and left visual fields, suggesting that normal thresholds require the cooperative activity of both posterior cerebral hemispheres, mediated by the corpus callosum. In contrast, there was superiority in the right visual field in naming, coping, and matching letter, number, and colors, but not unfamiliar shapes. The results are attributed to a differential effect of experience on perception in each visual field. The right-visual-field superiority in learning to perceive arrays on letters, numbers, and colors may result directly from the superiority of the left hemisphere in speech.

Adult↗
PubMed1980

Crossed aphasia in a dextral: a clinicopathological study.

Severe Broca aphasia and left hemiplegia without right limb apraxia occurred suddenly in a right-handed man with no personal or family history of left-handedness. Postmortem examination showed infarction of the right hemisphere, limited almost entirely to the precentral gyrus. In this patient, cerebral dominance for speech lay in the right hemisphere, but dominance for limb praxis lay in the left. This case provides evidence that cerebral dominance for speech and handedness in dextrals may be dissociated. It also suggests that lesions of the precentral gyrus are of major importance in producing Broca aphasia.

Aged↗
PubMed1979

Language after bilateral cerebral infarctions: role of the minor hemisphere in speech.

Language was studied in four patients with bilateral cerebral infarctions. Bilateral destruction of the third frontal gyri did not necessarily produce the severely limited language output characteristic of global or severe Broca aphasia; for Broca aphasia to occur, there must be extensive frontoparietal damage in the dominant cerebral hemisphere. Thus, the marked recovery of language after lesions limited to the dominant third frontal gyrus is mediated by adjacent areas of the dominant hemisphere, and not by the nondominant third frontal gyrus. The nondominant hemisphere nevertheless has a limited capacity to produce oral speech after extensive damage to the dominant hemisphere and may play an appreciable, although still subsidiary, role in normal articulation. The central gyri and rolandic operculum may be more essential than the third frontal gyri for well-articulated speech.

Adult↗