Intact reading in patients with profound early visual dysfunction.
Despite substantial neuroscientific evidence for a region of visual cortex dedicated to the processing of written words, many studies continue to reject explanations of letter-by-letter (LBL) reading in terms of impaired word form representations or parallel letter processing in favour of more gener...
| Published in: | Cortex: A Journal Devoted to the Study of the Nervous System & Behavior Vol. 49; no. 9; pp. 2294 - 2307 |
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| Main Authors: | , , , |
| Format: | research Journal Article |
| Published: |
Masson SPA
2013 Oct
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| Online Access: | View this record in EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=ccm&AN=107914494&site=ehost-live header: @attributes: shortDbName: ccm uiTerm: 107914494 longDbName: CINAHL Complete uiTag: AN controlInfo: bkinfo: dissinfo: jinfo: jid: 00109452 GMP jtl: Cortex: A Journal Devoted to the Study of the Nervous System & Behavior issn: 00109452 maglogo: N pubinfo: dt: 2013 Oct vid: 49 iid: 9 pid: 12473 pub: Masson SPA artinfo: ui: 107914494 107914494 NLM23578749 2012336305 10.1016/j.cortex.2013.01.009 NLM23578749 PMC3902200 107914494 ppf: 2294 ppct: 13 formats: tig: atl: Intact reading in patients with profound early visual dysfunction. aug: au: Yong, Keir X X Warren, Jason D Warrington, Elizabeth K Crutch, Sebastian J affil: Dementia Research Centre, Department of Neurodegeneration, UCL Institute of Neurology, University College London, UK. Electronic address: yong@drc.ion.ucl.ac.uk. sug: subj: Visual Perception Physiology Reading Occipital Lobe Physiopathology Aged Aged, 80 and Over Atrophy Pathology Dyslexia Physiopathology Female Human Middle Age Neuropsychological Tests Reaction Time Physiology Occipital Lobe Physiology Aged: 65+ years Aged, 80 & over Middle Aged: 45-64 years Female ab: Despite substantial neuroscientific evidence for a region of visual cortex dedicated to the processing of written words, many studies continue to reject explanations of letter-by-letter (LBL) reading in terms of impaired word form representations or parallel letter processing in favour of more general deficits of visual function. In the current paper, we demonstrate that whilst LBL reading is often associated with general visual deficits, these deficits are not necessarily sufficient to cause reading impairment and have led to accounts of LBL reading which are based largely on evidence of association rather than causation. We describe two patients with posterior cortical atrophy (PCA) who exhibit remarkably preserved whole word and letter reading despite profound visual dysfunction. Relative to controls, both patients demonstrated impaired performance on tests of early visual, visuoperceptual and visuospatial processing; visual acuity was the only skill preserved in both individuals. By contrast, both patients were able to read aloud words with perfect to near-perfect accuracy. Reading performance was also rapid with no overall significant difference in response latencies relative to age- and education-matched controls. Furthermore, the patients violated a key prediction of general visual accounts of LBL reading - that pre-lexical impairments should result in prominent word length effects; in the two reported patients, evidence for abnormal word length effects was equivocal or absent, and certainly an order of magnitude different to that reported for LBL readers. We argue that general visual accounts cannot explain the pattern of reading data reported, and attribute the preserved reading performance to preserved direct access to intact word form representations and/or parallel letter processing mechanisms. The current data emphasise the need for much clearer evidence of causality when attempting to draw connections between specific aspects of visual processing and different types of acquired peripheral dyslexia. pubtype: Academic Journal doctype: research Journal Article ougenre: Article language: English refInfo: holdings: @attributes: islocal: N |
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