Lesion localization of phonological agraphia

Alexander, Michael P.; Friedman, Rhonda B.; Loverso, Felice L.; Fischer, Richard S.

doi:10.1016/0093-934x(92)90022-7

Cited by 65 publications

(48 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…As mentioned previously, these effects are occurring in the ventral left visual processing pathway-precisely where they would be expected to occur on the basis of anatomical and human lesion data. Attributing these effects to phonological access is less consistent with available lesion data, which link phonological impairments -including phoneme recognition deficits, phonological dyslexias, phonemic paraphasia and phonological dysgraphia -to lesions in the superior temporal lobe and temporoparietal junction (Alexander et al, 1992;Beauvois and Derouesne, 1979;Caplan et al, 1995;Damasio and Damasio, 1980;Marin, 1980) rather than to lesions in the ventral visual pathway.…”

Section: Discussionmentioning

confidence: 94%

Tuning of the human left fusiform gyrus to sublexical orthographic structure

et al. 2006

View full text Add to dashboard Cite

Neuropsychological and neurophysiological evidence point to a role for the left fusiform gyrus in visual word recognition, but the specific nature of this role remains a topic of debate. The aim of this study was to measure the sensitivity of this region to sublexical orthographic structure. We measured blood oxygenation (BOLD) changes in the brain with functional magnetic resonance imaging while fluent readers of English viewed meaningless letter strings. The stimuli varied systematically in their approximation to English orthography, as measured by the probability of occurrence of letters and sequential letter pairs (bigrams) comprising the string. A whole-brain analysis showed a single region in the lateral left fusiform gyrus where BOLD signal increased with letter sequence probability; no other brain region showed this response pattern. The results suggest tuning of this cortical area to letter probabilities as a result of perceptual experience and provide a possible neural correlate for the 'word superiority effect' observed in letter perception research.Much evidence supports the idea that perceptual systems become selectively efficient at processing inputs that are encountered frequently. In learning a written language, for example, human brains appear to become tuned to the recurring visual patterns of the language represented in its orthographic structure. This is illustrated by the fact that letters embedded in words (such as S in the English word FLASH) or in word-like letter strings (S in FRISH) are more efficiently recognized than letters embedded in unusual letter strings (S in RFHSL) (McClelland and Rumelhart, 1981;Reicher, 1969). Such evidence suggests that normal readers use information about frequently recurring letter combinations, encoded as a result of experience with a specific written language, to more efficiently perceive and identify letters and letter strings.Neuropsychological evidence for an orthographic processor in the brain comes from patients who exhibit 'letter-by-letter reading' after left occipitotemporal brain injury (Binder and Mohr, 1992;Cohen et al., 2003;Leff et al., 2001;Sakurai et al., 2000). Such patients have normal language functions, including good recognition of single letters, but show profoundly impaired processing of letter strings, suggesting focal damage to systems responsible for storing or using orthographic information (Behrmann et al., 1998;Patterson and Kay, 1982;Warrington and Shallice, 1980). This localization is supported by neuroimaging experiments in normal readers, which have identified a region in the lateral left fusiform (occipitotemporal) gyrus that responds more strongly to words and word-like nonwords than to consonant letter strings or nonsense characters Dehaene et al., 2001;Polk and Farah, 2002 1999). Several elegant studies showed that this orthographic system employs an abstract code that is unaffected by changes in letter case (Dehaene et al., 2001Polk and Farah, 2002).Although activation in this brain region appears to be relat...

show abstract

Section: Discussionmentioning

confidence: 94%

Tuning of the human left fusiform gyrus to sublexical orthographic structure

et al. 2006

View full text Add to dashboard Cite

show abstract

“…Similarly, it has been proposed that damage to the frontal operculum played a central role in the pathogenesis of phonological dyslexia (Fiez and Petersen, 1998;Fiez et al, 2006), but there are also reports of patients with lesions confined to posterior perisylvian cortex (for a review, see Lambon Ralph and Graham, 2000). Thus, lesion-deficit correlations to date have failed to identify a single cortical area essential for sublexical reading and spelling, leading some investigators to propose that phonological dyslexia and dysgraphia may be caused by damage to a number of perisylvian cortical regions that are components of a distributed neural network dedicated to phonological processing (Alexander et al, 1992;Rapcsak and Beeson, 2002;Henry et al, 2007). The distributed nature of phonological processing is supported by functional imaging studies in normal individuals that typically reveal activation in multiple functionally linked perisylvian cortical regions during speech production/perception and phonological awareness tasks (for reviews, see Binder and Price, 2001;Vigneau et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Phonological dyslexia and dysgraphia: Cognitive mechanisms and neural substrates

Rapcsak

Beeson

Henry

et al. 2009

Cortex

184

155

View full text Add to dashboard Cite

To examine the validity of different theoretical assumptions about the neuropsychological mechanisms and lesion correlates of phonological dyslexia and dysgraphia, we studied written and spoken language performance in a large cohort of patients with focal damage to perisylvian cortical regions implicated in phonological processing. Despite considerable variation in accuracy for both words and non-words, the majority of participants demonstrated the increased lexicality effects in reading and spelling that are considered the hallmark features of phonological dyslexia and dysgraphia. Increased lexicality effects were also documented in spoken language tasks such as oral repetition, and patients performed poorly on a battery of phonological tests that did not involve an orthographic component. Furthermore, a composite measure of general phonological ability was strongly predictive of both reading and spelling accuracy, and we obtained evidence that the continuum of severity that characterized the written language disorder of our patients was attributable to an underlying continuum of phonological impairment. Although patients demonstrated qualitatively similar deficits across measures of written and spoken language processing, there were quantitative differences in levels of performance reflecting task difficulty effects. Spelling was more severely affected than reading by the reduction in phonological capacity and this differential vulnerability accounted for occasional disparities between patterns of impairment on the two written language tasks. Our findings suggest that phonological dyslexia and dysgraphia in patients with perisylvian lesions are manifestations of a central or modality-independent phonological deficit rather than the result of damage to cognitive components dedicated to reading or spelling. Our results also provide empirical support for shared-components models of written language processing, according to which the same central cognitive systems support both reading and spelling. Lesiondeficit correlations indicated that phonological dyslexia and dysgraphia may be produced by damage to a variety of perisylvian cortical regions, consistent with distributed network models of phonological processing.

show abstract

“…In brief, semantic processing is thought to engage anterior and inferolateral temporal regions (BA 38,20,21) as well as inferior prefrontal cortex (BA 47), and the angular gyrus (BA 39;Binder & Price, 2001;Mummery et al, 2000;Vandenberghe et al, 1996). The phonological codes involved in spelling rely on a network of perisylvian cortical regions, including Broca's area, Wernicke's area, the supramarginal gyrus, and insula (Alexander et al, 1992;Fiez, 1997;Omura et al, 2004;Roeltgen et al, 1983). Orthographic knowledge of lexical representations for reading and spelling is thought to engage a critical region within temporo-occipital cortex (BA 37), sometimes referred to as the visual word form area (Beeson et al, 2003b;Cohen & Dehaene, 2004;Nakamura et al, 2002;Rapcsak & Beeson, 2004).…”

Section: Introductionmentioning

confidence: 99%

Combining treatment for written and spoken naming

Beeson

Egnor

2006

J. Inter. Neuropsych. Soc.

View full text Add to dashboard Cite

Individuals with left-hemisphere damage often have concomitant impairment of spoken and written language. Whereas some treatment studies have shown that reading paired with spoken naming can benefit both language modalities, little systematic research has been directed toward the treatment of spelling combined with spoken naming. The purpose of this study was to examine the therapeutic effect of pairing a lexical spelling treatment referred to as Copy and Recall Treatment (CART) with verbal repetition of target words. This approach (CART + Repetition) was compared with treatment using verbal repetition without the inclusion of orthographic training (Repetition Only). Two individuals with moderate aphasia and severe impairment of spelling participated in the study using a multiple baseline design across stimulus sets and treatment conditions. Both participants improved spelling of targeted words as well as spoken naming of those items, but improvement in spoken naming was marked for one individual in the CART + Repetition condition, while the other participant made smaller gains in spoken than written naming irrespective of treatment condition. Consideration of the participant profiles suggested that CART + Repetition provides greater benefit when there is some residual phonological ability and the treatment serves to stimulate links between orthography and phonology.

show abstract

Lesion localization of phonological agraphia

Cited by 65 publications

References 13 publications

Tuning of the human left fusiform gyrus to sublexical orthographic structure

Tuning of the human left fusiform gyrus to sublexical orthographic structure

Phonological dyslexia and dysgraphia: Cognitive mechanisms and neural substrates

Combining treatment for written and spoken naming

Contact Info

Product

Resources

About