Interaction of attentional and lexical processes in neglect dyslexia

Left- and right-hemisphere forms of phonological alexia

“…Many experimental studies concerned with reading words and nonwords have reported findings that right-hemisphere patients omit or misread letters on the left part of the stimulus (Arduino, Burani, & Vallar, 2002;Kinsbourne & Warrington, 1962;Làdavas et al, 1997;Vallar, Burani, & Arduino, 2010, for a review). Moreover, in neglect dyslexia words can often be read better than nonwords (e.g., Hillis & Caramazza, 1995;Làdavas et al, 1997;Riddoch, Humphreys, Cleton, & Fery, 1990). One obvious possibility, then, is that the surprising findings in the right posterior group can be explained in terms of neglect dyslexia.…”

“Paradoxical neglect”: spatial representations, hemisphere-specific activation, and spatial cueing

“…Hence, were differences in the number of beginnings crucial, performance should be worse with high-than with low-frequency words. Positive effects of word frequency on reading accuracy have been observed in other cases of neglect dyslexia (Riddoch et al, 1990). For EL, the effect may be due to better guessing of high-relative to low-frequency words or to top-down feedback for high-frequency words enhancing poor visual encoding (Mozer & Behrmann, 1990).…”

“…The frequency effect in reading seems unlikely to be due to factors such as differences in the number of possible beginnings of high-and low-frequency words. If anything, high-frequency words tend to have more orthographic neighbours than do low-frequency words (Gernsbacher, 1984), and patients with neglect dyslexia tend to manifest neglect more strikingly with words with more orthographic neighbours (Riddoch et al, 1990). Hence, were differences in the number of beginnings crucial, performance should be worse with high-than with low-frequency words.…”

“…It should be noted that patients with right cerebral lesions frequently neglect the left sides of words in reading (Ellis, Flude, & Young, 1987;Riddoch et al, 1990 have argued that the right-hemisphere lesion results in increased right-side orienting within the string. Initial letters no longer fall with the "span of apprehension" following initial fixation within a word, and neglect errors result (Riddoch & Humphreys, 1993;Riddoch et al, 1990).…”

“…Work with brain-damaged subjects lends support to the notion that the overall attentional capacity has been reduced. Thus, in patients with neglect, the effect of increasing task difficulty is often to increase substantially the amount of neglect (Rapcsack, Verfaellie, Fleet, & Heilman, 1989;Riddoch, Humphreys, Cleton, & Fery, 1990). The effect of reduced attentional capacity may not only be apparent contralesionally; thus, Robertson (1989) patients with right-sided lesions will omit items on the right side of space when they have been cued to the left.…”