Processing deficits for familiar and novel faces in patients with left posterior fusiform lesions

Pure alexia (PA) arises fromdamage to the left posterior fusiformgyrus (pFG) and the striking reading disorder that defines this condition has meant that such patients are often cited as evidence for the specialisation of this regiontoprocessing of writtenwords.There is,however, an alternative view that suggests this region is devoted to processing of high acuity foveal input, which is particularly salient for complex visual stimuli like letter strings. Previous reports have highlighted disrupted processing of non-linguistic visual stimuli after damage to the left pFG, both for familiar and unfamiliar objects and also for novel faces. This study explored the nature of face processing deficits in patients with left pFG damage. Identification of famous faces was found to be compromised in both expressive and receptive tasks. Discrimination of novel faces was also impaired, particularly for those that varied in terms of second-order spacing information, and this deficit was most apparent for the patients with the more severe reading deficits. Interestingly, discrimination of faces that varied in terms of feature identity was considerably better in these patients and it was performance in this condition that was related to the size of the length effects shown in reading. This finding complements functional imaging studies showing left pFG activation for faces varying only in spacing and frontal activation for faces varying only on features. These results suggest that the sequential part-based processing strategy that promotes the length effect inthe reading of these patients also allows themto discriminate between faces on the basis of feature identity, but processing of second-order configural information is most compromised due to their left pFG lesion. This study supports a view in which the left pFG is specialised for processing of high acuity foveal visual information that supports processing of both words and faces.variou

Do reading processes differ in transparent versus opaque orthographies? A study of acquired dyslexia in Welsh/English bilinguals.

In English, the relationship between the written and spoken forms of words is relatively opaque, leading to proposals that skilled reading requires two procedures: (a) a sublexical grapheme/phoneme conversion process allowing the correct reading of regular words (CAT) and new or pseudowords (ZAT); (b) a lexical process necessary to read irregular words accurately (TWO) and assumed to be the dominant process for familiar words. However, it has been argued that the sublexical process may be sufficient in highly transparent languages such as Welsh. If this is the case, damage to the sublexical process may lead to more severe deficits in transparent languages due to the lack of an alternative lexical process. To test this hypothesis, we compared Welsh and English oral reading and written-word recognition and comprehension in seven bilingual stroke participants with comparably impaired pseudoword reading in English and Welsh. Performance was remarkably similar across languages. Irrespective of the language tested, words were read more accurately than pseudowords. Lexical decision and word comprehension were as accurate in Welsh and in English, and when imageability effects were present they were of a similar size in both languages. This study does not support the hypothesis that orthographic transparency determines the nature of cognitive reading processes, but rather suggests that readers develop a sight vocabulary through reading experience irrespective of orthographic transparenc