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Biomedical subjects

L J Rothi

Publications and source records attributed to L J Rothi.

36 records · Page 2Linked to original sources
PubMed1992

Morphologic agrammatism following a right hemisphere stroke in a dextral patient.

There is evidence of two major components of grammatic function in the brain: (1) morphologic, probably based in the postcentral perisylvian cortex, encompassing the selection of individual words and inflectional endings according to the rules of grammar; and (2) syntactic, probably based in the frontal lobes, encompassing construction of the overall structure of a sentence (syntax) to match the concept being considered. We present a stroke patient with impaired morphology but, unlike Broca's aphasics, relative sparing of syntax. He omitted 43% of articles, 40% of complementizers, 20% of pronouns, 27% of semantically marked prepositions, 43% of purely grammatic prepositions, and 22% of auxiliary verbs, but his average sentence length was 9.8 words and 64% of his sentences contained embedded clauses. He frequently intermingled two sentences to convey a given concept, juxtaposing words in grammatically unacceptable ways. This intermingling may represent either a grammatic "conduite d'approche," or a failure of the filtering function of a defective morphologic processor. His great difficulty in completing syntactic frames suggests that a more general form of the processes underlying grammatic morphology may play an important role in phrase structure generation.

Aged↗
PubMed1992

Conceptual apraxia in Alzheimer's disease.

Theoretical models of praxis have two major components, a praxis conceptual system that includes knowledge of tool use and mechanical knowledge and a praxis production system that includes the information needed to program skilled motor acts. Because patients with Alzheimer's disease may have an impairment of the central conceptual system, we wanted to learn if they had a conceptual apraxia by testing their knowledge of the type of actions associated with tool use, their ability to associate tools with objects that receive their action, their ability to understand the mechanical nature of problems and the mechanical advantages tools may afford. We studied 32 subjects with probable Alzheimer's disease and 32 controls by examining tool-action relationships and tool-object associations. We tested mechanical knowledge by having subjects select alternative tools and solve mechanical puzzles by developing new tools. The Alzheimer's group was subdivided into four groups based on the presence or absence of ideomotor apraxia and a lexical-semantic deficit. Results indicated that each of the four Alzheimer's groups differed from normal controls on at least some measures of conceptual apraxia, suggesting that Alzheimer's patients do have a disturbance of the praxis conceptual system and that impairment of this system is not directly related to language impairment or ideomotor apraxia.

Aged↗
PubMed1991

The relationship between buccofacial and limb apraxia.

There are at least two possible models depicting the relationship between buccofacial and limb apraxia. First, apraxia can be viewed as a unitary motor disorder which transcends the output modalities of both buccofacial and limb output. A high degree of similarity between the two types of apraxia would support this model. Alternatively, the relationship between buccofacial and limb apraxia may not include a unitary mechanism. The presence of quantitative and qualitative differences between buccofacial and limb performance would support this nonunitary model. The results of the present study support the nonunitary model.

Adult↗
PubMed1990

Three-dimensional computergraphic analysis of apraxia. Neural representations of learned movement.

The left cerebral hemisphere in man contains anatomical structures specialized not only for language but also for higher-order motor programming. One method of studying the nature of these motor programs is by observing the type of errors made by patients who have left hemisphere damage. A major problem, however, in investigating the disorders that result from failure of this specialized left hemisphere system (the apraxias) has been the difficulty in obtaining objective measurement of movement in three-dimensional space. To this end, we provide the first three-dimensional analysis of the nature of movement errors in apraxia. Two apraxic subjects with lesions to the left hemisphere and 5 matched control subjects were studied. The apraxic subjects showed impairments in the control of movement timing and spatial relations, as well as decoupling in the normally tight relation between certain spatial and temporal aspects of their movement trajectories. Further, the use of the distal musculature by apraxic subjects was more impaired than their use of the proximal musculature, suggesting more distal representation in any space-time maps of learned movement. These data provide further insight into the nature of the representations of learned skilled movements in the left cerebral hemisphere.

Aged↗
PubMed1989

Ideational apraxia: a deficit in tool selection and use.

We report a 67-year-old left-handed man who exhibited an ideational apraxia in both clinical and nonclinical natural settings following a right hemisphere infarction. His inability to use tools could not be explained by a motor production deficit (ideomotor apraxia), because he made content errors and could not match tools with objects. His deficit could not be attributed to an agnosia or language comprehension deficit, because he could name tools and point to tools on command. Based on our testing, it appeared that this patient had a loss of knowledge related to tool use.

Aged↗
PubMed1986

Pantomime agnosia.

Visual agnosia is impaired visual recognition not explained by defective visual acuity, visual fields, attention, or general mental ability. Two nonapraxic patients with lesions in the left occipital lobe could imitate pantomimes they could not recognise. Although both patients had a hemianopia, sparing of gesture imitation shows that no visual defect accounts for their inability to recognise pantomimes. Both patients were amnestic and alexic but had no general impairment of cognitive ability to account for a pantomime-recognition disorder. These patients seem to have agnosia for pantomime. From the computed tomograms from these patients, we propose that inferior visual association cortex is critical for gesture comprehension, whereas superior portions of these structures are critical for imitating or performing pantomime to an object presented visually.

Aged↗
PubMed1986

Multimodal agnosia after unilateral left hemisphere lesion.

Agnosia is an abnormality of recognition that is not explained by sensory or cognitive disorders. We studied a patient who had combined visual-tactile agnosia without prosopagnosia after a left hemisphere infarct. Although he copied figures presented visually and he performed intramodal or crossmodal visual-tactile matches, he could not indicate recognition by either sight or touch. The lesion involved areas of the occipital and temporal lobes that may be important for human performance of tasks that require construction and application of meaning to percepts presented both visually and tactually.

Agnosia↗
PubMed1985

Pantomime comprehension and ideomotor apraxia.

In a prior study it was shown that apraxic patients with posterior infarctions that included the parietal lobe could not discriminate between gestures. In this study these observations were replicated using a nonverbal paradigm in which the subjects did not have to discriminate between gestures, but instead had to comprehend their meaning. Pantomimed acts on videotape were shown to six apraxic-aphasic patients, seven nonapraxic-aphasic patients, and six normal subjects. Four drawings were also shown, one of which matched the pantomime (for example, if the pantomime was of hammering, one drawing was of a nail and three were foils). Subjects responded by pushing a button corresponding to the desired picture. The apraxics made more errors than the aphasics or controls.

Adult↗
PubMed1984

Acquisition and retention of gestures by apraxic patients.

The purpose of this study was to examine whether apraxic-aphasic patients with parietal lesions had difficulty learning lists of gestures and whether the performance deficits they displayed resulted from an inability either to consolidate this information in memory or to retrieve the information once stored. The findings indicate that apraxic-aphasic patients do have difficulty acquiring lists of gestures. This inability to reproduce gestural information was not associated with a retrieval disorder, but instead the apraxic-aphasic subjects could not consolidate the information in memory.

Aged↗
PubMed1984

Reading: selective sparing of closed-class words in Wernicke's aphasia.

One aspect of Broca's aphasia, induced by anterior perisylvian lesions, is an inability to read closed-class words (eg, articles, prepositions) with a preserved ability to read open-class words (eg, nouns, verbs). We examined a man with profound Wernicke's aphasia induced by an infarct of the posterior portion of the superior temporal gyrus (Wernicke's area). He could not read substantive words or pronounceable nonwords but could read closed-class words. These observations suggest that the reading of closed- and open-class words is mediated by separable systems. Whereas the anterior perisylvian region appears to be important in reading functional words, the posterior perisylvian region is important in reading substantive words.

Aged↗
PubMed1983

Restitution and substitution: two theories of recovery with application to neurobehavioral treatment.

This article reviews two theories regarding recovery from brain damage in adulthood. The notion of restitution of function assumes that behavioral improvement results from the increasing integrity of the injured functional system. In contrast, the theory of substitution of function assumes that improvement results from system reorganization or compensation. Both these processes take place during the course of neurologic recovery. The ability of the clinical neuropsychologist to maximize behavioral changes in the brain-damaged patient during the recovery period requires an appreciation for these recovery mechanisms. Treatment decisions can be enhanced by knowledge of the time course, degree of recovery potential, and behavioral constraints of these complementary recovery processes.

Behavior Therapy↗
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↗
PubMed1982

Transcortical aphasia from ischaemic infarcts of the thalamus: a report of two cases.

Thalamic injury from various natural causes, including tumours an haemorrhage, has been reported to lead abnormalities of language. The pathophysiology of these language disorders remains controversial because the naturally occurring thalamic lesions often are associated with mass effects. Two patients are described with hypodense left thalamic lesions, shown by computed tomography, probably representing infarction. Both patients had aphasia, but neither had evidence of appreciable brain swelling or distortion, nor were cortical language areas damaged.

Adolescent↗
PubMed1982

Two forms of ideomotor apraxia.

Destruction of parietal areas containing visuokinesthetic motor engrams, where motor acts may be programmed, should be distinguishable from apraxia induced by disconnection of these parietal areas from frontal motor areas. Destruction should result in inability to distinguish well-performed from poorly performed movements, whereas disconnection should not. We gave movement and act-discrimination tasks to apraxic and nonapraxic patients with anterior lesions or nonfluent aphasia, and to patients with posterior lesions or fluent aphasia. On both tasks, the performance of posterior/fluent patients was worse than that of all other patients. Our results suggest that there are two types of patients with ideomotor apraxia.

Aphasia, Broca↗