1/67. "What" and "how": evidence for the dissociation of object knowledge and mechanical problem-solving skills in the human brain.patients with profound semantic deterioration resulting from temporal lobe atrophy have been reported to use many real objects appropriately. Does this preserved ability reflect (i) a separate component of the conceptual knowledge system ("action semantics") or (ii) the operation of a system that is independent of conceptual knowledge of specific objects, and rather is responsible for general mechanical problem-solving skills, triggered by object affordances? We contrast the performance of three patients-two with semantic dementia and focal temporal lobe atrophy and the third with corticobasal degeneration and biparietal atrophy-on tests of real object identification and usage, picture-based tests of functional semantic knowledge, and a task requiring selection and use of novel tools. The patient with corticobasal degeneration showed poor novel tool selection and impaired use of real objects, despite near normal semantic knowledge of the same objects' functions. The patients with semantic dementia had the expected deficit in object identification and functional semantics, but achieved flawless and effortless performance on the novel tool task. Their attempts to use this same mechanical problem-solving ability to deduce (sometimes successfully but often incorrectly) the use of the real objects provide no support for the hypothesis of a separate action-semantic system. Although the temporal lobe system clearly is necessary to identify "what" an object is, we suggest that sensory inputs to a parietal "how" system can trigger the use of objects without reference to object-specific conceptual knowledge.- - - - - - - - - - ranking = 1keywords = focal (Clic here for more details about this article) |
2/67. Making requests: illustrations of how right-hemisphere brain damage can affect discourse production.This article examines several factors that influence the production of requests for behavior. Using a role-play methodology, we elicited request productions from well-recovered patients with right-hemisphere brain damage (RHD) and from non brain-damaged control participants. The stimulus items represented variation both on interpersonal factors based on characteristics of the people in the interaction and on situational factors based on what was being requested. A large corpus of responses was elicited from each patient. Responses were coded for request directness, amount of explanatory material over and above the request proper (a relatively demanding method for manipulating the tone of a request), and use of "please" (a relatively simple device for signaling a request). Case-by-case analysis of the patients' performances revealed some common areas of abnormality and also some idiosyncratic features. Some patients produced less explanatory supportive material than control participants, and they tended not to vary the amount of explanatory material as a function of the request scenario. Of interest is that some of the same patients overused "please," and varied their use of this simple device as a function of request scenarios. The discourse strategies observed were likely due to deficits both in pragmatic awareness and in planning utterances. One implication of these results concerns an apt description of the abnormal discourse of RHD patients. The relative lack of supportive explanatory material in their requests may result in patients' seeming rude or inappropriate.- - - - - - - - - - ranking = 1.0976189003269keywords = simple (Clic here for more details about this article) |
3/67. Short-term memory deficit after focal parietal damage.The neuropsychological symptomatology is reported for a 44-year-old patient of normal intelligence, EE, after removal of a circumscribed left hemispheric tumor the major part of which was located in the angular gyrus and in the subcortical white matter. EE had a distinct and persistent short-term memory impairment together with an equally severe impairment in transcoding numbers. On the other hand, his performance was flawless in calculation tasks and in all other tests involving number processing. Impairments in language tests could be attributed to his short-term memory deficit, which furthermore was characterized by a strong primacy effect in the absence of a recency effect. His graphomotoric output was temporarily inhibited. The patient, with a strong left-sided dominance, manifested a bi-hemispherical activation of the Broca and Wernicke regions in a positron-emission-tomographic investigation when required to produce verbs which he was to derive from nouns. The findings in EE suggest that unilateral and restricted lateral parietal damage can result in a profound short-term memory deficit together with a transcoding deficit for stimuli extending over only a few digits or syllables in the absence of any symptoms of the gerstmann syndrome.- - - - - - - - - - ranking = 4keywords = focal (Clic here for more details about this article) |
4/67. Persisting aphasia as the sole manifestation of partial status epilepticus.OBJECTIVES: Persisting aphasia presenting as an isolated inability to vocalize is an uncommon presentation of simple partial status epilepticus and only eight such cases have been reported over the past 40 years. methods: We studied a patient with a 5-year history of recurrent episodes of inability to talk, without any other motor or cognitive impairments. Episodes lasted as long as 24 h, interictal EEGs were normal and she was diagnosed as a conversion disorder. RESULTS: EEG recordings during one of the episodes showed continuous discharges in the right frontal and parasagital areas demonstrating the ictal nature of the deficits. During the episode the patient had no deficits of strength, or in her ability to perform skilled movements to command, imitation or manipulation of objects. comprehension of complex verbal commands was preserved and she would make attempts to articulate words and correctly answered questions with head nodding or monosyllables, yes or no. She could hum but had no other vocalizations. CONCLUSIONS: This is the first case of aphasic status epilepticus secondary to epileptogenic discharges of the right hemisphere. The case is also unique for the isolated involvement of production of language during the seizure.- - - - - - - - - - ranking = 27.497968574162keywords = seizure, simple (Clic here for more details about this article) |
5/67. del (9p) syndrome: proposed behavior phenotype.Over recent years interest in the study of behavior phenotypes has gained increasing momentum. We present three white female patients, age respectively 9 years 9 months, 14 years 6 months and 18 years at the time of the last observation, seen because of developmental delay/mental retardation, seizures and learning disabilities. cytogenetic analysis showed a de novo deletion of the short arm of chromosome 9 in all three, with the breakpoint being located at band 9p22. Although several studies have described the somatic phenotype, analytical evaluation of verbal and non-verbal cognitive functions are lacking. Our patients received a detailed neuropsychological and linguistic evaluation that showed a particular behavior profile, in the context of mental retardation of variable degree. On selective tests there was a marked deficit in visuo-praxic and visuo-spatial skills associated with memory disturbance. Visuo-motor integration abilities [VMI; Beery, 1997] and visuo-perceptual and visuo-spatial abilities [Benton line orientation test, 1992] seemed particularly impaired, both in relation to verbal mental age (vocabulary and grammatical production/comprehension) and to some non-verbal competencies [Benton face recognition test, 1992]. The profile shows advanced performances in face recognition. In addition, there is also a dissociation between verbal and visuo-spatial short term memory. This behavior phenotype is similar to that of williams syndrome (WS) individuals. Our patients also showed some unusual within-domain dissociations regarding linguistic abilities. To better demonstrate similarities and differences between the behavior phenotypes of the del (9p22) syndrome and WS, we studied three IQ-gender-matched WS subjects. The comparison between the cognitive phenotypes of the two syndromes shows similarities in neuropsychological pattern. We hypothesize that there is a gene within the 9p22 region responsible for the neuropsychological profile described here.- - - - - - - - - - ranking = 26.949159123999keywords = seizure (Clic here for more details about this article) |
6/67. Bilateral resective epilepsy surgery in a child with tuberous sclerosis: case report.OBJECTIVE AND IMPORTANCE: Surgical intervention can reduce the burden of seizures in selected patients with tuberous sclerosis and medically refractory epilepsy. CLINICAL PRESENTATION: A child presented with tuberous sclerosis and severe epilepsy beginning in the first month of life and delayed development before 1 year of age. Video-electroencephalographic monitoring at the age of 1 year revealed a left temporal seizure focus. Repeat videoelectroencephalography at 2 years of age revealed a right posterior quadrant seizure focus. Bilateral subdural electrodes were placed, confirming independent seizure onsets from the right parietal area (overlying a tuber) and prominent interictal activity over the left superior temporal region. INTERVENTION: The right parietal focus was resected, and electrodes were maintained over the left temporal focus. After right parietal resection, ictal discharges were recorded over the left temporal region; a corticectomy was performed 2 days later. No tonicoclonic or complex partial seizures have occurred during a follow-up period of more than 24 months. Simple partial motor seizures involving the right foot have been reduced by more than 80%, and other simple partial seizures have been eliminated. Postoperatively, there has been marked improvement in the patient's cognitive and motor developmental status. CONCLUSION: In selected patients with bilateral seizure foci involving separate lobes, aggressive bilateral surgery can be safe and effective.- - - - - - - - - - ranking = 2234.8709765705keywords = epilepsy, seizure, simple (Clic here for more details about this article) |
7/67. 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.- - - - - - - - - - ranking = 336.45481568806keywords = epilepsy (Clic here for more details about this article) |
8/67. Recovery of language after left hemispherectomy in a sixteen-year-old girl with late-onset seizures.hemispherectomy is a very effective surgical treatment for intractable seizures that occur in the setting of Rasmussen's syndrome. The decision of when to perform a dominant hemispherectomy depends greatly on how late the surgeon believes some shift in language to the nondominant hemisphere can occur. We report a right-handed patient with Rasmussen's syndrome who underwent a left hemispherectomy at the age of 16 and has had excellent control of her seizures and remarkable language recovery. Our results indicate that dominant hemispherectomy in adolescence in the setting of late-onset seizures and Rasmussen's syndrome in the profoundly aphasic patient does not commit the patient to the prognosis of a fixed language deficit.- - - - - - - - - - ranking = 188.64411386799keywords = seizure (Clic here for more details about this article) |
9/67. A complicated case of cortical deafness in a child.overall motor retardation and clumsiness; bilateral pyramidal signs; extensor plantar responses; extra pyramidal symptoms; central hearing loss; perception disorders almost exclusively for linguistic items; diffuse E.E.G. abnormalities with focal maxima in both temporal regions.- - - - - - - - - - ranking = 1keywords = focal (Clic here for more details about this article) |
10/67. Language dysfunction in epileptic conditions.epilepsy may disrupt brain functions necessary for language development by its associated intellectual disabilities or directly as a consequence of the seizure disorder. Additionally, in recent years, there has been increasing recognition of the association of epileptiform electroencephalogram (EEG) abnormalities with language disorders and autism spectrum disorders. Any process that impairs language function has long-term consequences for academic, social, and occupational adjustments in children and adolescents with epilepsy. Furthermore, impairments in specific language abilities can impact memory and learning abilities. This article reviews interictal language function in children and adults with epilepsy; epilepsy surgery and language outcome; and language disorders associated with abnormal EEGs. The relationship between epilepsy and language function is complicated as the neuroanatomic circuits common to both overlap. We demonstrate how magnetoencephalography (MEG) offers the ability to analyze the relationship of language, EEG abnormalities, and epilepsy.- - - - - - - - - - ranking = 1709.2232375643keywords = epilepsy, seizure (Clic here for more details about this article) |
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