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Query: UMLS:C0220723 (PCA)
 4,687 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We investigated the neuropsychological correlates of left posterior cerebral artery (LPCA) infarcts with a quantitative systematic approach and found a pattern of impairment extending well beyond the classical syndrome of alexia without agraphia. Sixteen consecutive patients with CT scan evidence of an infarct confined to the territory of LPCA were given a battery of tests assessing the following abilities. (1) Reading and writing; (2) naming and pointing to colours; (3) naming the same 30 objects on visual (objects and coloured photographs), tactile and verbal presentation; and (4) verbal memory. These tests were administered to large control samples and the performance of LPCA patients was considered pathological if it fell below the score of the last or second to last control patient. Seventy five per cent of PCA patients had alexia without agraphia. Although a lesion of the CT scan slice where the pineal is represented appeared to be crucially associated with alexia, the severity of the disorder increased when contiguous upper or lower slices were also involved. Not only colour anomia, but also object and especially photograph anomia could almost always be shown in alexics and were highly correlated with the degree of the reading impairment. The naming deficit was also present when items were presented in the tactile and verbal modality, in spite of the integrity of the oral language areas. Every right-handed patient, alexic as well as nonalexic, was impaired on at least two of the three verbal memory tests and most on all of them. The findings are discussed in terms of the anatomofunctional mechanisms subserving verbal memory and the transmission of visual information to the speech areas.
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PMID:The pattern of neuropsychological impairment associated with left posterior cerebral artery infarcts. 367 94

BACKGROUND: It has been proposed that anomia following left inferior temporal lobe lesions may have two different underlying mechanisms with distinct neural substrates. Specifically, naming impairment following damage to more posterior regions (BA 37) has been considered to result from a disconnection between preserved semantic knowledge and phonological word forms (pure anomia), whereas anomia following damage to anterior temporal regions (BAs 38, 20/21) has been attributed to the degradation of semantic representations (semantic anomia). However, the integrity of semantic knowledge in patients with pure anomia has not been demonstrated convincingly, nor were lesions in these cases necessarily confined to BA 37. Furthermore, evidence of semantic anomia often comes from individuals with bilateral temporal lobe damage, so it is unclear whether unilateral temporal lobe lesions are sufficient to produce significant semantic impairment. AIMS: The main goals of this study were to determine whether anomia following unilateral left inferior temporal lobe damage reflected a loss of semantic knowledge or a post-semantic deficit in lexical retrieval and to identify the neuroanatomical correlates of the naming impairment. METHODS #ENTITYSTARTX00026; PROCEDURES: Eight individuals who underwent left anterior temporal lobectomy (L ATL) and eight individuals who sustained left posterior cerebral artery strokes (L PCA) completed a battery of language measures that assessed lexical retrieval and semantic processing, and 16 age- and education-matched controls also completed this battery. High-resolution structural brain scans were collected to conduct lesion analyses. OUTCOMES #ENTITYSTARTX00026; RESULTS: Performance of L ATL and L PCA patients was strikingly similar, with both groups demonstrating naming performance ranging from moderately impaired to unimpaired. Anomia in both groups occurred in the context of mild deficits to semantic knowledge, which manifested primarily as greater difficulty in naming living things than nonliving things and greater difficulty in processing visual/perceptual as opposed to functional/associative semantic attributes. Lesion analyses indicated that both patient groups sustained damage to anterior inferior temporal lobe regions implicated in semantic processing. CONCLUSIONS: These results contribute to a better understanding of the cognitive mechanism of naming impairment in patients with temporal lobe damage and support the notion that pure anomia and semantic anomia represent two endpoints along a continuum of semantic impairment. Unilateral left temporal lobe lesions in our patients resulted in relatively mild semantic deficits that were apparent primarily in lexical production tasks, whereas severe semantic impairment likely requires bilateral temporal lobe damage.
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PMID:Lexical retrieval and semantic knowledge in patients with left inferior temporal lobe lesions. 1975 27