Intralesionally implanted cisplatin plus systemic carmustine for the treatment of brain tumor in rats

Early alexia and higher visual impairments characterize Posterior cortical atrophy (PCA), a progressive dementing syndrome most often caused by Alzheimer disease. Posterior cortical atrophy is rare, and the nature of the visual impairments in PCA are unclear. The authors observed two patients who had an insidiously progressive reading difficulty characterized by letter-by-letter reading and otherwise intact cognitive functions. Over time, these patients developed "ventral simultanagnosia" with preserved detection of multiple stimuli but inability to interpret whole scenes. Subsequently, they progressed to Balint syndrome with "dorsal simultanagnosia," optic ataxia, and oculomotor apraxia. Structural imaging was normal, but functional imaging revealed posterior cortical dysfunction. On a letter reading task, both patients had a word superiority effect, and on a whole word reading task, they could not read most words with missing or crosshatched letters. An inability to assess whole scenes progressed to an inability to detect more than one stimulus in an array. These findings suggest an evolution of PCA with progressive difficulty in visual integration beginning with letters, progressing to whole scenes, and culminating in Balint syndrome. These changes may reflect an extension of the pathophysiology of PCA from the extrastriate visual cortex to its occipitotemporal and occipitoparietal connections.     

Deficits in auditory temporal and spectral resolution in language-impaired children

Between 3 and 6 per cent of children who are otherwise unimpaired have extreme difficulties producing and understanding spoken language. This disorder is typically labelled specific language impairment. Children diagnosed with specific language impairment often have accompanying reading difficulties (dyslexia), but not all children with reading difficulties have specific language impairment. Some researchers claim that language impairment arises from failures specific to language or cognitive processing. Others hold that language impairment results from a more elemental problem that makes affected children unable to hear the acoustic distinctions among successive brief sounds in speech. Here we report the results of psychophysical tests employing simple tones and noises showing that children with specific language impairment have severe auditory perceptual deficits for brief but not long tones in particular sound contexts. Our data support the view that language difficulties result from problems in auditory perception, and provide further information about the nature of these perceptual problems that should contribute to improving the diagnosis and treatment of language impairment and related disorders.     

Reading comprehension.

Four major assumptions drive current psychological research on the reading comprehension process: (a) Skilled reading depends on the complex interaction of cognitive, linguistic, and perceptual processes; (b) reading is an interactive process; (c) our ability to process textual information is constrained by the limits of our information processing ability; and (d) reading is strategic. Emerging evidence points to prior knowledge and cognitive and metacognitive processes as critical for the development of skilled reading comprehension. Evidence suggests that instruction on the processes underlying comprehension can improve a reader's comprehension skills. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sensitivity to dynamic auditory and visual stimuli predicts nonword reading ability in both dyslexic and normal readers

BACKGROUND: Developmental dyslexia is a specific disorder of reading and spelling that affects 3-9% of school-age children and adults. Contrary to the view that it results solely from deficits in processes specific to linguistic analysis, current research has shown that deficits in more basic auditory or visual skills may contribute to the reading difficulties of dyslexic individuals. These might also have a crucial role in the development of normal reading skills. Evidence for visual deficits in dyslexia is usually found only with dynamic and not static stimuli, implicating the magnocellular pathway or dorsal visual stream as the cellular locus responsible. Studies of such a dissociation between the processing of dynamic and static auditory stimuli have not been reported previously. RESULTS: We show that dyslexic individuals are less sensitive both to particular rates of auditory frequency modulation (2 Hz and 40 Hz but not 240 Hz) and to dynamic visual-motion stimuli. There were high correlations, for both dyslexic and normal readers, between their sensitivity to the dynamic auditory and visual stimuli. Nonword reading, a measure of phonological awareness believed crucial to reading development, was also found to be related to these sensory measures. CONCLUSIONS: These results further implicate neuronal mechanisms that are specialised for detecting stimulus timing and change as being dysfunctional in many dyslexic individuals. The dissociation observed in the performance of dyslexic individuals on different auditory tasks suggests a sub-modality division similar to that already described in the visual system. These dynamic tests may provide a non-linguistic means of identifying children at risk of reading failure.     

Dissociation of letter and picture naming resulting from callosal disconnection

BACKGROUND: Detailed mapping of the corpus callosum for functional fractionation in humans remains incomplete. OBJECTIVE: To examine separable interhemispheric transfer of visual information by callosal fibers, especially in the splenium. METHODS: We examined callosal disconnection signs in a 14-year-old boy with a lesion confined to the posterior part of the splenium and reviewed reported cases with callosal lesions. RESULTS AND CONCLUSION: The patient presented with left hemialexia as the only manifestation of callosal disconnection syndrome. The only difficulty demonstrated was in reading aloud or copying letters, which were presented tachistoscopically to the left visual field, with his right hand. He could copy letters presented to his left visual field with his left hand, however. Therefore, left hemialexia was not due to hemiamblyopia or hemineglect. There was no anomia for pictures and colors in the left visual field. MRI revealed that the lesion was limited to the ventroposterior end of the splenium. Review of 40 reported patients with callosal lesions suggests that the anterior to middle part of the splenium is involved in transferring picture information from the language-nondominant hemisphere to the language-dominant hemisphere and that the ventroposterior part is involved in transferring letter information.     

Comparison of reading and spelling in patients with probable Alzheimer's disease.

Patients with probable Alzheimer's disease (AD) are reported to show mild, but reliable, difficulties reading aloud and spelling to dictation exception words, which have unusual or unpredictable correspondence between their spelling and pronunciation (e.g., touch). To understand the cognitive dysfunction responsible for these impairments, 21 patients and 27 age- and education-matched controls completed specially designed tests of single-word oral reading and spelling to dictation. AD patients performed slightly below controls on all tasks and showed mildly exaggerated regularity effects (i.e., the difference in response accuracy between words with regular spellings minus exception words) in reading and spelling. Qualitative analyses, however, did not demonstrate response patterns consistent with impairment in central lexical orthographic processing. The authors conclude that the mild alexia and agraphia in AD reflect semantic deficits and nonlinguistic impairments rather than a specific disturbance in lexical orthographic processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hierarchical control and skilled typing: Evidence for word-level control over the execution of individual keystrokes.

Routine actions are commonly assumed to be controlled by hierarchically organized processes and representations. In the domain of typing theories, word-level information is assumed to activate the constituent keystrokes required to type each letter in a word. We tested this assumption directly using a novel single-letter probe technique. Subjects were primed with a visual or auditory word or a visually presented random consonant string and then probed to type a single letter from the prime or another randomly selected letter. Relative to randomly selected letters, probe responses were speeded for first, middle, and last letters contained in visual and auditory word primes but not for middle and last letters contained in random consonant primes. This suggests that word-level information causes parallel activation of constituent keystrokes, consistent with hierarchical processing. The role of hierarchical processing in typing and routine action is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive processes as predictors of word recognition and reading comprehension in learning-disabled and skilled readers: Revisiting the specificity hypothesis.

Examines how cognitive processes interrelate as well as predict learning-disabled (LD) readers' word recognition and reading comprehension performance. Correlations between phonological, orthographic, semantic, metacognitive, and working memory measures with reading performance were examined in LD and skilled readers (aged 8–12 yrs). LD Ss were deficient on all cognitive processes compared with skilled Ss, but these differences do not reflect IQ scores. Reading ability group differences emerged on a component composed primarily of working memory measures (referred to as "g") as well as unique components, suggesting that these differences emerge on both general and specific (modular) processes. G best predicts reading comprehension for both groups, and phonological awareness best predicts skilled Ss' pseudoword reading, whereas g best predicts LD Ss' pseudoword performance. Overall, LD Ss' information processing difficulties were described within a general working memory model that views such children as having difficulty accessing and coordinating both general and specific processes. Results suggest that the cognitive processes that contribute to reading deficits are best understood in the context of their combination with other operations rather than in isolation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual complexity in letter-by-letter reading: "pure" alexia is not pure

Standard accounts of pure alexia have favoured the view that this acquired disorder of reading arises from damage to a left posterior occipital cortex mechanism dedicated to the processing of alphanumeric symbols. We challenge these accounts in two experiments and demonstrate that patients with this reading deficit are also impaired at object identification. In the first experiment, we show that a single subject, EL, who shows all the hallmark features of pure alexia, is impaired at picture identification across a large set of stimuli. As the visual complexity of pictures increases, so EL's reaction time to identify the stimuli increases disproportionately relative to the control subjects. In the second experiment, we confirm these findings with a larger group of five pure alexic patients using a selected subset of high- and low-visual complexity pictures. These findings suggest that the deficit giving rise to pure alexia is not restricted to orthographic symbols per se but, rather, is a consequence of damage to a more general-purpose visual processing mechanism.     

Increased processing enhances calibration of comprehension.

Two experiments investigated whether increased processing increases the relation between test performance predictions and test performance, i.e., increases calibration of comprehension. The amount of processing of text was manipulated by having subjects read intact text or text with deleted letters. In Experiment 1, intact versus deleted letters were manipulated within subjects, and subjects made either comprehension ease or test prediction ratings. Paragraphs with deleted letters produced higher correlations between predictions and test performance than did intact paragraphs. Better calibration with more processing was not observed for ratings of comprehension ease. In Experiment 2, in a between-subjects design, the prediction results were replicated; calibration was better for text with deleted letters than for intact text. The results show that subjects can predict performance on text material with greater than chance accuracy and that these predictions are better when subjects do more active processing during reading. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Crohn''s disease in infancy: a case report

We present a patient with pure alexia following a hemorrhagic infarction in the left fusiform gyrus. The symptom began with alexia preferentially disturbed for kana, but during the course of recovery slight agraphia for kanji became pronounced. In the earlier phase, alexia was more severe than agraphia and he could write kanji that he could not read. Furthermore, kinesthetic reading was effective. These findings are consistent with the symptoms of pure alexia, although the fact that a writing disturbance for kanji persisted resembles the profile of alexia with agraphia for kanji due to a posterior inferior temporal lesion. Based on the fact that the posterior inferior temporal lesion showed more severe agraphic symptom and more frequent nonresponse writing errors of kanji, and that our patient's lesion was mainly located in the fusiform gyrus that is medial to the inferior temporal gyrus, we believe that alexia occurred when the inferior temporal gyrus was disconnected from the fusiform gyrus, as a result, visual information could not reach the inferior temporal gyrus in which the visual images of individual kanji are stored.     

Visual requirements for reading

We have applied research on the visual psychophysics of reading to low vision assessment. Research on different aspects of the reading process found that reading rate rather than reading comprehension is more sensitive to variations in a subject's visual functioning or the stimulus properties of print. The research identified four different visual factors that significantly affect reading rate: (1) acuity reserve [print size relative to acuity threshold], (2) contrast reserve [print contrast relative to contrast threshold], (3) field of view [number of letters visible], and (4) in cases of maculopathy, central scotoma size. Our research indicates that fluent reading rates can be attained with a restricted field of view, as little as four characters. However, attainment of fluent reading levels requires that print size and contrast should be several times threshold and the diameter of a central scotoma should be less than 22 degrees. Although important clinical studies are lacking, we derived specific visual requirements for different reading rates from published experimental research to provide a starting point and to illustrate how visual requirements could be derived, even with poor correlations. Research has made significant progress toward the development of a comprehensive low vision assessment that will allow the practitioner to identify visual impediments to reading, other than reduced visual acuity. Having more fully characterized a visual impairment, the practitioner may tailor devices or interventions to the individual's needs and capabilities.     

Prolonged P300 latency in attention deficit hyperactivity disorder predicts poor response to imipramine

P300 is a cognitive evoked potential that evaluates attention and information processing. This study uses auditory and visual P300 topography to develop a classification of attention deficit hyperactivity disorder (ADHD), and find predictors of treatment response. Of 45 ADHD children ages 6 to 15 treated with pemoline in a previous study, 25 were poor responders. Of these 25, 17 participated in an imipramine treatment protocol. Auditory and visual P300 testing was performed before and after treatment using 31 scalp electrodes. Good and poor responders to imipramine were clinically identical. Poor imipramine responders had longer auditory and visual P300 latencies than good responders. Treatment with imipramine decreased auditory P300 latencies and increased auditory P300 amplitudes. We have previously reported that ADHD patients with small right frontocentral auditory P300 amplitudes respond poorly to pemoline. Thus, P300 topography and latency classifies ADHD into three groups: group 1 with normal P300 topography, and good response to pemoline; group 2 with small right frontocentral auditory P300 amplitudes, poor response to pemoline, and good response to imipramine; and group 3 with long auditory and visual P300 latencies and small right frontocentral auditory P300 amplitudes, and poor response to pemoline and imipramine.     

A study of visual processes in a case of interhemispheric disconnexion

A 75-year-old right-handed woman, after a probable cerebral infarct, developed an irregular constriction of the visual fields, a left-sided agraphia, and an anomia for objects in the left hand. Subsequent testing demonstrated an inability to name, though ability to recognize, letters and objects flashed in the homonymous left visual field. An inter-hemispheric disconnexion syndrome was inferred from these findings. The present publication concerns mainly the visual aspects of this disconnexion syndrome. Tasks were devised to test the abilities of the major and minor hemisphere: (a) the left hemisphere demonstrated a complete dominance for language expression and an incomplete dominance for written language comprehension; (b) the right hemisphere appeared to be dominant for some visuo-spatial tasks including number comprehension; (c) when the hemispheres were given contradictory visual informations on a non-verbal task (chimeric stimuli) there was a predominance of the right hemisphere. The right hemisphere appeared able to process complex information. Specialization of functional activities in each hemisphere is briefly discussed.     

Auditory short-term memory and digit span: Normal versus poor readers.

Investigated the relationship between reading comprehension level, digit span, and short-term memory for Morse codelike temporal patterns in 3 experiments. Consistent with previous research on children, Exp I using 60 undergraduates demonstrated that Ss performed better when the 1st pattern was auditory than when it was visual or tactual. In Exps II and III with 36 undergraduates and 98 5th graders, respectively, no relationship was found between digit span and accuracy in comparing patterns of tones presented a few seconds apart. However, both tasks discriminated between children with normal and poor reading comprehension scores on a standardized test (Reading Comprehension subtest of the California Achievement Tests). It appears that these 2 tasks index fundamental processes that underlie reading comprehension. Digit span seems to assess an individual's ability to rapidly develop meaningful codes in memory for incoming verbal stimuli. The auditory pattern comparison procedure appears to measure ability to maintain information in short-term memory. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Distinctions between reading comprehension and locating information in text.

Reading comprehension is usually operationalized as text recall. However, locating information such as facts, names, or numbers in text is a reading task requiring comprehension that is distinct from text recall in two respects: (1) cognitive processes that control reading comprehension and locating information are expected to be different; (2) the frequency of engagement in comprehension and locating are expected to be independent. We examined these expectations by identifying 4 reading tasks frequently performed by 45 electronics engineers and technicians. Real world reading tasks were simulated with sets of test items in the following domains: (a) comprehending articles, (b) locating information in schematics, (c) locating information in articles, and (d) locating information in manuals. Factor analyses for both the engineers and technicians resulted in two factors, one for comprehension (a) and one for locating information (b, c, d), with a correlation of less than .20. Factor analyses of reading engagement for both groups resulted in factors of (a) comprehending articles, (b) locating information in articles, (c) reading schematics, and (d) reading manuals. Canonical correlations for both groups showed no association between reading engagement variables and reading competence (comprehending and locating) variables. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Naive theories of intelligence and the role of processing fluency in perceived comprehension.

Previous research overwhelmingly suggests that feelings of ease people experience while processing information lead them to infer that their comprehension is high, whereas feelings of difficulty lead them to infer that their comprehension is low. However, the inferences people draw from their experiences of processing fluency should also vary in accordance with their naive theories about why new information might be easy or difficult to process. Five experiments that involved reading novel texts showed that participants who view intelligence as a fixed attribute, and who tend to interpret experiences of processing difficulty as an indication that they are reaching the limits of their ability, reported lower levels of comprehension as fluency decreased. In contrast, participants who view intelligence as a malleable attribute that develops through effort, and who do not tend to interpret experiences of processing difficulty as pertaining to some innate ability, did not report lower levels of comprehension as fluency decreased. In fact, when these participants were particularly likely to view effort as leading to increased mastery, decreases in fluency led them to report higher levels of comprehension. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Seeing and hearing rotated faces: influences of facial orientation on visual and audiovisual speech recognition

It is well-known that facial orientation affects the processing of static facial information, but similar effects on the processing of visual speech have yet to be explored fully. Three experiments are reported in which the effects of facial orientation on visual speech processing were examined using a talking face presented at 8 orientations through 360 degrees. Auditory and visual forms of the syllables /ba/, /bi/, /ga/, /gi/, /ma/, /mi/, /ta/, and /ti/ were used to produce the following speech stimulus types: auditory, visual, congruent audiovisual, and incongruent audiovisual. Facial orientation did not affect identification of visual speed per se or the near-perfect accuracy of auditory speech report with congruent audiovisual speech stimuli. However, facial orientation did affect the accuracy of auditory speech report with incongruent audiovisual speech stimuli. Moreover, the nature of this effect depended on the type of incongruent visual speech used. Implications for the processing of visual and audiovisual speech are discussed.     

Isolation of a cytokinin gene, ZOG1, encoding zeatin O-glucosyltransferase from Phaseolus lunatus

University students who were skilled or less-skilled readers were compared on tests of auditory information processing and immediate serial recall of auditory and visual digits. Reading skill was defined by performance on a pseudoword reading task. The good readers exhibited typical modality effects with higher recall of auditory than visual items from the last 3 serial positions. On the terminal list item, the less-skilled readers showed a modality effect comparable with that of the skilled readers, but on other list items the modality effect reversed and a visual superiority was obtained. Results were discussed in terms of C. G. Penney's (1989) separate-streams model of short-term verbal memory.