scholarly journals Testing the interhemispheric deficit theory of dyslexia using the visual half-field technique

2020 ◽  
Vol 73 (7) ◽  
pp. 1004-1016
Author(s):  
AR Bradshaw ◽  
DVM Bishop ◽  
ZVJ Woodhead
Keyword(s):  
Visual Field ◽  
Left Hemisphere ◽  
Right Visual Field ◽  
Adult Participants ◽  
Significant Difference ◽  
Additional Processing ◽  
Control Adult ◽  
The Right ◽  
Neuropsychological Theory ◽  
Deficit Theory

A deficit in interhemispheric transfer has been proposed as a neuropsychological theory of dyslexia. Interactions between the hemispheres during word recognition can be studied using the visual half-field paradigm. The well-established recognition advantage for right visual field (RVF) words over left visual field (LVF) words is thought to reflect the additional processing costs associated with callosal transfer of LVF word representations to the language-specialised left hemisphere. In addition, a further gain in recognition for bilateral presentation of a word has been attributed to cooperative interactions between the hemispheres. These recognition advantages can therefore be seen as behavioural indices of the efficiency of callosal transfer. This study aimed to replicate the finding of an absence of the bilateral advantage in developmental dyslexia, previously reported by Henderson et al. In all, 47 dyslexic and 43 control adult participants were tested, and no significant difference was found in the size of the bilateral advantage between the two groups. Our data did however replicate the previous finding of an increased RVF-LVF difference in dyslexic participants caused by poorer accuracy for LVF words (i.e., a greater LVF cost). This evidence is compatible with the interhemispheric deficit theory of dyslexia, suggesting an impairment in the transfer of visual word information from the right to the left hemisphere during reading.

scholarly journals Testing the interhemispheric deficit theory of dyslexia using the visual half-field technique

2019 ◽  
Author(s):  
Abigail Bradshaw ◽  
Dorothy Vera Margaret Bishop ◽  
Zoe Victoria Joan Woodhead
Keyword(s):  
Visual Field ◽  
Left Hemisphere ◽  
Right Visual Field ◽  
Adult Participants ◽  
Significant Difference ◽  
Additional Processing ◽  
Control Adult ◽  
The Right ◽  
Neuropsychological Theory ◽  
Deficit Theory

A deficit in interhemispheric transfer has been proposed as a neuropsychological theory of dyslexia. The role of interactions between the hemispheres during word recognition is demonstrated in two behavioural effects robustly reported using the visual half field paradigm. The well-established recognition advantage for right visual field (RVF) words over left visual field (LVF) words reflects the additional processing costs associated with callosal transfer of LVF word representations to the language specialised left hemisphere. Additionally, a further gain in recognition for bilateral presentation of a word is attributed to cooperative interactions between the hemispheres. These recognition advantages can therefore be seen as behavioural indices of the efficiency of callosal transfer. This study aimed to replicate the finding of an absence of the bilateral advantage in developmental dyslexia, previously reported by Henderson, Barca and Ellis (2007). 47 dyslexic and 43 control adult participants were tested, and no significant difference found in the size of their bilateral advantages. Our data did however replicate the previous finding of an increased RVF advantage in right handed dyslexic participants caused by poorer accuracy for LVF words. This evidence provides partial support for the interhemispheric deficit theory of dyslexia, suggesting an impairment in the transfer of visual word information from the right to the left hemisphere during reading.

Right Hemisphere Memory Bias Does Not Extend to Involuntary Memories for Negative Scenes

Perception ◽  
2021 ◽  
Vol 50 (1) ◽  
pp. 27-38
Author(s):  
Ella K. Moeck ◽  
Nicole A. Thomas ◽  
Melanie K. T. Takarangi
Keyword(s):  
Visual Field ◽  
Left Hemisphere ◽  
Right Hemisphere ◽  
Visual Fields ◽  
Memory Bias ◽  
Right Visual Field ◽  
Hemispheric Differences ◽  
Involuntary Memory ◽  
Involuntary Memories ◽  
The Right

Attention is unequally distributed across the visual field. Due to greater right than left hemisphere activation for visuospatial attention, people attend slightly more to the left than the right side. As a result, people voluntarily remember visual stimuli better when it first appears in the left than the right visual field. But does this effect—termed a right hemisphere memory bias—also enhance involuntary memory? We manipulated the presentation location of 100 highly negative images (chosen to increase the likelihood that participants would experience any involuntary memories) in three conditions: predominantly leftward (right hemisphere bias), predominantly rightward (left hemisphere bias), or equally in both visual fields (bilateral). We measured subsequent involuntary memories immediately and for 3 days after encoding. Contrary to predictions, biased hemispheric processing did not affect short- or long-term involuntary memory frequency or duration. Future research should measure hemispheric differences at retrieval, rather than just encoding.

Functional Hemispheric Asymmetry and Belief in ESP: Towards a “Neuropsychology of Belief”

1993 ◽  
Vol 77 (3_suppl) ◽  
pp. 1299-1308 ◽  
Author(s):  
Peter Brugger ◽  
Alex Gamma ◽  
René Muri ◽  
Markus Schafer ◽  
Kirsten I. Taylor
Keyword(s):  
Visual Field ◽  
Lexical Decision ◽  
Left Hemisphere ◽  
Hemispheric Asymmetry ◽  
Right Hemisphere ◽  
Right Visual Field ◽  
Decision Task ◽  
Verbal Tasks ◽  
Hemisphere Dominance ◽  
The Right

30 right-handed subjects were given a lateralized tachistoscopic lexical-decision task. Subjects' belief in extrasensory perception (ESP) was assessed with a single six-point scale; 16 subjects were designated as believers in ESP and 14 subjects as nonbelievers. Believers in ESP did not exhibit a hemispheric asymmetry for the task while nonbelievers exhibited the expected right visual-field/left-hemisphere dominance documented in the literature. Believers' lack of asymmetry was not caused by an impaired left-hemisphere performance but rather by a significantly enhanced lexical-decision accuracy in the left visual field/right hemisphere compared to nonbelievers. These results are compatible with previous studies indicating a correlation between belief in ESP and a bias for right-hemisphere processing. Moreover, the results are relevant for a discussion of an association between paranormal beliefs and schizotypy: highly schizotypal individuals are not only particularly prone to believe in ESP but are also known to show an attenuation of hemispheric asymmetries in lateralized verbal tasks due to an enhanced contribution of the right hemisphere. We suggest that the neurological basis of delusion-like beliefs may involve a release of right-hemisphere function from left-hemisphere control and sketch the focus of research for a future “neuropsychology of belief.”

Asynchrony of Lateral Onset as a Factor in Difference in Visual Field

1976 ◽  
Vol 42 (1) ◽  
pp. 163-166 ◽  
Author(s):  
Takeshi Hatta
Keyword(s):  
Visual Field ◽  
Left Hemisphere ◽  
Left Visual Field ◽  
Right Visual Field ◽  
Perceptual Process ◽  
Experimental Conditions ◽  
Stimulus Interval ◽  
Laterality Effect ◽  
The Right

An experiment in matching judgments was designed to examine a role of perceptual process in apparent asymmetry. Recognition of Hirakana letters (Japanese letters) was required. The experimental condition in which stimuli were presented to the left visual field first and to the right visual field second produced more errors for all stimulus intervals (0 to 60 msec.) than experimental conditions where stimuli were presented to the right visual field first and to the left one second. Especially, superiority of the latter condition was marked with the longest stimulus interval employed. These results indicate superiority of the left hemisphere function for recognizing Hirakana letters and suggest that not only memory but also perceptual process contributes to this laterality effect.

Cognitive Arithmetic: Evidence for Right Hemispheric Mediation in an Elementary Component Stage

1980 ◽  
Vol 32 (1) ◽  
pp. 69-84 ◽  
Author(s):  
Albert N. Katz
Keyword(s):  
Visual Field ◽  
Left Hemisphere ◽  
Right Hemisphere ◽  
Reaction Times ◽  
Right Visual Field ◽  
Spatial Order ◽  
Elementary Component ◽  
Cognitive Arithmetic ◽  
The Right ◽  
Field Errors

Earlier studies involving the lateralization of arithmetic abilities have provided evidence for both right and left hemisphere superiorities. It is argued here that part of this inconsistency could be due to the complexity of the arithmetic computations which have been examined. The present studies examined a subprocess shown to be involved in more complex tasks, such as subtraction. The subprocess is the identification of which of two numbers is greater, and was tested by the flashing of a pair of digits to either the left or right visual field. Errors, reaction-times to make a decision, and examination of hand × visual field interactions all indicated that this subprocess is mediated by the right hemisphere. Correlational analysis was used to identify the operations underlying the observed lateralization of this ability. This analysis indicated that an operation indexed by the spatial order in which the digits were presented was effective in the right hemisphere but not the left hemisphere. Speculations on the nature of these operations were presented.

Categorical versus Coordinate Spatial Processing: Effects of Blurring and Hemispheric Asymmetry

1994 ◽  
Vol 6 (2) ◽  
pp. 156-164 ◽  
Author(s):  
Elizabeth L. Cowin ◽  
Joseph B. Hellige
Keyword(s):  
Visual Field ◽  
Visual Information ◽  
Right Hemisphere ◽  
Visual Fields ◽  
Spatial Processing ◽  
Right Visual Field ◽  
Horizontal Line ◽  
Significant Difference ◽  
Categorical Task ◽  
The Right

The present experiment examined the effects of dioptric blurring on the performance of two different spatial processing tasks using the same visual stimuli. One task (the above/below, categorical task) required subjects to indicate whether a dot was above or below a horizontal line. The other task (the coordinate, near/far task) required subjects to indicate whether the dot was within 3 mm of the line. For both tasks, the stimuli on each trial were presented to either the right visual field and left hemisphere (RVF/LH) or the left Visual field and right hemisphere (LVF/RH). For the above/below task, dioptric blurring consistently increased reaction time (RT) and did so equally on LVF/RH and RVF/LH trials. Furthermore, there was no significant difference between the two visual fields for either clear or blurred stimuli. For the near/far task, dioptric blurring had no consistent effect on either RT or error rate for either visual field. On an initial block of trials, however, there were significantly fewer errors on LVF/RH than on RVF/LH trials, with the LVF/RH advantage being independent of whether the stimuli were clear or blurred. This initial LVF/RH advantage disappeared quickly with practice, regardless of whether the stimuli were clear or blurred. This pattern of results suggests that for both cerebral hemispheres, somewhat different aspects of visual information are relevant for categorical versus coordinate spatial processing and that the right hemisphere is superior to the left for coordinate (but not categorical) spatial processing.

Role of Interstimulus and Stimulus-Hemisphere Compatibility in the Process of Interhemispheric Integration

1988 ◽  
Vol 67 (2) ◽  
pp. 503-512 ◽  
Author(s):  
Jean-Marc Berger ◽  
Etienne Perret ◽  
Annemarie Zimmermann
Keyword(s):  
Visual Field ◽  
Left Hemisphere ◽  
Normal Subjects ◽  
Right Visual Field ◽  
Pictorial Representation ◽  
Compatibility Analysis ◽  
Compound Nouns ◽  
The Right

Normal subjects had to name German compound nouns which were presented tachistoscopically. The compound nouns were displayed either unilaterally to the left or right visual field, or bilaterally with one element to the left and one to the right visual field. A distinction was made between the bilateral conditions as to whether the representation of the elements, printed and/or pictorial, included a high or low interstimulus and a high or low stimulus-hemisphere compatibility. Analysis indicated firstly a superiority of the left hemisphere for the naming of compound nouns in mixed print and pictorial representation. Secondly, the performance in the bilateral conditions was moderated by stimulus-hemisphere compatibility. In the process of interhemispheric integration stimulus-hemisphere compatibility proved more crucial than interstimulus compatibility. Analyses of errors further illustrated hemispheric behaviour.

Hemispheric Asymmetries for Temporal Resolution: A Signal Detection Analysis of Threshold and Bias

1994 ◽  
Vol 47 (2) ◽  
pp. 291-310 ◽  
Author(s):  
Michael E. R. Nicholls
Keyword(s):  
Visual Field ◽  
Signal Detection ◽  
Left Hemisphere ◽  
Right Hemisphere ◽  
Right Visual Field ◽  
Hemispheric Asymmetries ◽  
Detection Analysis ◽  
Signal Detection Analysis ◽  
Temporal Events ◽  
The Right

Divided visual field techniques were used to investigate hemispheric asymmetries for (a) the threshold of fusion of two flashes of light and (b) the detection of simultaneous versus successive events for a group of normal, right-handed adults. A signal detection analysis revealed a higher level of accuracy for the right visual field-left hemisphere (RVF-LH) relative to the left visual field-right hemisphere (LVF-RH) for both tasks. These results were interpreted in terms of a general left-hemisphere advantage for the discrimination of fine temporal events. The implications of these results for models of temporary asymmetry that describe the left hemisphere's advantage in terms of an exclusive specialization or relative superiority are then discussed.

Differential Visual Field-Interhemispheric Transfer: Can it Explain Sex and Handedness Differences in Lateralization?

1987 ◽  
Vol 65 (2) ◽  
pp. 423-429 ◽  
Author(s):  
Richard H. Haude ◽  
Mary Morrow-Tlucak ◽  
Diane M. Fox ◽  
Kevin B. Pickard
Keyword(s):  
Visual Field ◽  
Left Hemisphere ◽  
Left Visual Field ◽  
Spatial Information ◽  
Right Hemisphere ◽  
Right Visual Field ◽  
Localization Task ◽  
Left Handed ◽  
Functional Lateralization ◽  
The Right

104 men and women were tested for visual field-hemispheric transfer of spatial information on a dot-localization task. Right-handed subjects showed significant improvement when stimuli were presented to the left visual field of the right hemisphere (LVF-RH) after practice on the same task presented to the right visual field of the left hemisphere (RVF-LH) first. No improvement was found when the task was presented in the reverse order (LVF-RH first followed by RVF-LH). It was concluded that, for right-handers, transfer of spatial information to the right hemisphere is facilitated while transfer to the left hemisphere is inhibited. Left-handed subjects demonstrated no significant improvement in either condition, suggesting inhibition or lack of transfer of spatial information in either direction. No sex differences were found in either right-handed or left-handed subjects. The findings suggest that there may be different mechanisms underlying the similarities in functional lateralization of women and left-handers.

Sex Differences in Hemispheric Asymmetry Revisited

1978 ◽  
Vol 47 (1) ◽  
pp. 315-321 ◽  
Author(s):  
H. Julia Hannay ◽  
Catherine L. Boyer
Keyword(s):  
Sex Differences ◽  
Visual Field ◽  
Left Hemisphere ◽  
Left Visual Field ◽  
Hemispheric Asymmetry ◽  
Right Visual Field ◽  
Males And Females ◽  
The Right ◽  
Significant Superiority

56 male and 56 female familial right-handers were given a tachistoscopic task requiring recognition of trigrams presented binocularly and vertically in the right or left visual field fot individually determined brief durations. Both males and females obtained a significant superiority in the right visual field and significant laterality coefficients indicative of processing by the left hemisphere. Implications for research on sex differences in hemispheric asymmetry are discussed.

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