Neglect dyslexia with a stimulus-centred deficit and without visuospatial neglect.

This paper reports a single case of ipsilesional left neglect dyslexia and interprets it according to the three-level model of visual word recognition proposed by Caramazza and Hillis (1990). The three levels reflect a progression from the physical stimulus to an abstract representation of a word. RR was not impaired at the first, retinocentric, level, which represents the individual features of letters within a word according to the location of the word in the visual field: She made the same number of errors to words presented in her left visual field as in her right visual field. A deficit at this level should also mean the patient neglects all stimuli. This did not occur with RR: She did not neglect when naming the items in rows of objects and rows of geometric symbols. In addition, although she displayed significant neglect dyslexia when making visual matching judgements on pairs of words and nonwords, she did not do so to pairs of nonsense letter shapes, shapes which display the same level of visual complexity as letters in words. RR was not impaired at the third, graphemic, level, which represents the ordinal positions of letters within a word: She continued to neglect the leftmost (spatial) letter of words presented in mirror-reversed orientation and she did not neglect in oral spelling. By elimination, these results suggest RR's deficit affects a spatial reference frame where the representational space is bounded by the stimulus: A stimulus-centred level of representation. We define five characteristics of a stimulus-centred deficit, as manifest in RR. First, it is not the case that neglect dyslexia occurs because the remaining letters in a string attract or capture attention away from the leftmost letter(s). Second, the deficit is continuous across the letter string. Third, perceptually significant features, such as spaces, define potential words. Fourth, the whole, rather than part, of a letter is neglected. Fifth, category information is preserved. It is concluded that the Caramazza-Hillis model accounts well for RR's data, although we conclude that neglect dyslexia can be present when a more general visuospatial neglect is absent.

The attentional blink reveals sluggish attentional shifting in adolescents with specific language impairment

Rapid processing deficits have been the subject of much debate in the literature on specific language impairment (SLI). Hari and Renvall (2001) [Hari, R. & Renvall, H. (2001). Impaired processing of rapid stimulus sequences in dyslexia. Trends in cognitive sciences, 5, 525–532.] proposed that the source of this deficit can be attributed to sluggish attentional shifting abilities. That is, more time is required to shift attention between stimuli. To test this claim, 26 adolescents with SLI (divided into two subgroups to control for differences in non-verbal intelligence) and 14 controls were presented with a rapid serial visual presentation task. In this task participants were asked to detect two visual targets presented serially with distracter items with varying inter-target intervals (i.e., time difference between targets). This task was designed to elicit an attentional blink (AB). The AB describes the phenomenon whereby non-impaired individuals are less likely to report the second of two targets presented within 200–500 ms of each other. After controlling for group differences in non-verbal intelligence, the SLI group was found to be significantly less accurate than the control group at successfully reporting the second target at inter-target intervals of 100, 200, 300, 400 and 800 ms. The results were interpreted to suggest that adolescents with language impairments have an AB which differs from non-impaired individuals in both magnitude and duration.

Temporal processing and reading disability

The present investigation examined thehypothesis that early auditory temporalprocessing deficits cause later specificreading disability by impairing phonologicalprocessing (Farmer & Klein 1995; Tallal1980, 1984). Temporal processing ability atschool entry was examined using Tallal'sRepetition Test in a large unselected sample ofover 500 children followed over subsequentyears. Although our data confirmed the presenceof certain non-speech auditory processingdeficits in children later classified asspecific reading-disabled, many findings wereclearly at odds with a causal interpretation ofthis relationship. (1) Reading-disabled (RD)children were impaired at school entry on thesubtest with long interstimulus intervals(ISIs) but not the critical short-ISIsubtest. (2) RD children were not inferior toreading-age (RA) controls. (3) A subgroup of RDchildren with evidence of temporal deficitswere no less proficient on later phonologicalor reading measures than RD children with noevidence of early temporal impairment. (4)Although there was a reliable concurrentcorrelation between temporal deficits andphonological awareness at school entry(suggesting a possible common causeexplanation), early temporal deficits did notpredict later phonological impairment,pseudoword processing difficulties, or specificreading disability. On the other hand, earlytemporal deficits did predict later oralreceptive vocabulary and reading comprehensionweaknesses. These findings suggest thatauditory temporal deficits in dyslexics may beassociated with the same dysphasic-typesymptoms observed by Tallal and her colleaguesin specific language-impaired populations, butdo not cause the core phonological deficitsthat characterize dyslexic groups.

Abstracts of the Inaugural Australian Conference for Cognitive Neuropsychology and Cognitive Neuropsychiatry

The first Australian Conference for Cognitive Neuropsychology and Cognitive Neuropsychiatry was conducted by the School of Psychology at Deakin University, Geelong, from Friday, July 13 to Sunday, July 15 and was attended by over 50 cognitive psychologists, neuropsychologists and speech pathologists from Australia, New Zealand, Singapore and the UK. The Conference aimed to bring together researchers from different disciplines including linguistics, psychology, philosophy and speech pathology to present research that relates (neuropsychological or psychiatric) impairment to theories of normal cognitive functioning. The scientific program of the conference included 24 papers of exceptional quality. They were organised into the following thematic sessions: Disorders of language comprehension and production; Semantic memory and category-specific disorders; Reading: development and acquired dyslexia; Writing: development and acquired dyslexia; Memory; Object and face recognition; Theory of mind; Misidentification syndromes. Keynote speakers were Professor Andy Young from the University of York, England and Professor Max Coltheart from the Macquarie Centre for Cognitive Sciences, Sydney.

Dyslexic and entrepreneur : typologies, commonalities and differences

There is anecdotal evidence as well as a small but growing research literature indicating there may be a higher incidence of dyslexia amongst entrepreneurs compared to business managers and to the general population. Studies indicate that while dyslexics may resist entry into mainstream business due to their generally low literacy levels, there appears to be no such barrier for dyslexics wanting to start new ventures. Given that dyslexics also dislike imposed structure, have strong oral and spatial skills, are intuitive/insightful/curious as well as resilient and determined, it is not suprising that they gravitate towards self-employment as opposed to highly organised corporate professions.