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Normal speed and accuracy of saccade and vergence eye movements in dyslexic reader children.

Bucci MP, Vernet M, Gerard CL, Kapoula Z - J Ophthalmol (2010)

Bottom Line: Results.Conclusion.It contrasts results on latencies related to visual attention dysfunction at cortical level.

View Article: PubMed Central - PubMed

Affiliation: FRE 3292 CNRS, Université René Descartes Paris V, 71 avenue Edouard Vaillant, 92774 Boulogne Billancourt Cedex, France.

ABSTRACT
Objective. Latency of eye movements depends on cortical structures while speed of execution and accuracy depends mostly on subcortical brainstem structures. Prior studies reported in dyslexic reader children abnormalities of latencies of saccades (isolated and combined with vergence); such abnormalities were attributed to deficits of fixation control and of visual attention. In this study we examine speed and accuracy characteristics of horizontal eye movements in natural space (saccades, vergence and combined movements) in dyslexic reader children. Methods. Two paradigms are tested: gap paradigm (fixation offset 200 ms prior to target onset), producing shorter latencies, in both non-dyslexic reader and dyslexic reader children and simultaneous paradigm. Seventeen dyslexic reader children (mean age: 12 +/- 0.08 years) and thirteen non-dyslexic reader children (mean age: 12 +/- 1 years) were tested. Horizontal eye movements from both eyes were recorded simultaneously by a photoelectric device (Oculometer, Dr. Bouis). Results. For all movements tested (saccades, vergence, isolated or combined) and for both paradigms, the mean velocity and accuracy were similar in dyslexic readers and non-dyslexic readers; no significant difference was found. Conclusion. This negative but important result, suggests no dysfunction of brainstem ocular motor circuits in dyslexic readers. It contrasts results on latencies related to visual attention dysfunction at cortical level.

No MeSH data available.


Related in: MedlinePlus

Mean velocity (amplitude of the movement/duration) of different types of eye movements in the gap (a) and (c) and in the simultaneous paradigm (b) and (d) for dyslexic (white bars) and non-dyslexic reader (gray bars) children. Vertical lines indicate standard error.
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fig2: Mean velocity (amplitude of the movement/duration) of different types of eye movements in the gap (a) and (c) and in the simultaneous paradigm (b) and (d) for dyslexic (white bars) and non-dyslexic reader (gray bars) children. Vertical lines indicate standard error.

Mentions: Figure 2 shows the mean velocity of all eye movements tested in the gap and in the simultaneous paradigm for the two groups of children (dyslexic and non-dyslexic); in Figures 2(a) and 2(b), movements with high mean velocity, saccades in pure and combined form are shown, and in Figures 2(c) and 2(d), movements with slow mean velocity (vergence pure and combined with saccades) are shown. Table 2 shows the minimum and the maximum mean velocity values for dyslexic and non-dyslexic reader children for each type of eye movements examined in the two paradigms. The mean velocity value for each type of eye movements examined in dyslexic readers is similar to that found in non-dyslexic readers. For each type of eye movements, the ANOVA does not show any significant difference between the two groups of children (F(1,28) = 1.43, P = .24); there is no significant effect of the paradigms and there is no significant interaction between the groups of children and the paradigms. In sum, speed of eye movements in dyslexic reader is normal.


Normal speed and accuracy of saccade and vergence eye movements in dyslexic reader children.

Bucci MP, Vernet M, Gerard CL, Kapoula Z - J Ophthalmol (2010)

Mean velocity (amplitude of the movement/duration) of different types of eye movements in the gap (a) and (c) and in the simultaneous paradigm (b) and (d) for dyslexic (white bars) and non-dyslexic reader (gray bars) children. Vertical lines indicate standard error.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2836913&req=5

fig2: Mean velocity (amplitude of the movement/duration) of different types of eye movements in the gap (a) and (c) and in the simultaneous paradigm (b) and (d) for dyslexic (white bars) and non-dyslexic reader (gray bars) children. Vertical lines indicate standard error.
Mentions: Figure 2 shows the mean velocity of all eye movements tested in the gap and in the simultaneous paradigm for the two groups of children (dyslexic and non-dyslexic); in Figures 2(a) and 2(b), movements with high mean velocity, saccades in pure and combined form are shown, and in Figures 2(c) and 2(d), movements with slow mean velocity (vergence pure and combined with saccades) are shown. Table 2 shows the minimum and the maximum mean velocity values for dyslexic and non-dyslexic reader children for each type of eye movements examined in the two paradigms. The mean velocity value for each type of eye movements examined in dyslexic readers is similar to that found in non-dyslexic readers. For each type of eye movements, the ANOVA does not show any significant difference between the two groups of children (F(1,28) = 1.43, P = .24); there is no significant effect of the paradigms and there is no significant interaction between the groups of children and the paradigms. In sum, speed of eye movements in dyslexic reader is normal.

Bottom Line: Results.Conclusion.It contrasts results on latencies related to visual attention dysfunction at cortical level.

View Article: PubMed Central - PubMed

Affiliation: FRE 3292 CNRS, Université René Descartes Paris V, 71 avenue Edouard Vaillant, 92774 Boulogne Billancourt Cedex, France.

ABSTRACT
Objective. Latency of eye movements depends on cortical structures while speed of execution and accuracy depends mostly on subcortical brainstem structures. Prior studies reported in dyslexic reader children abnormalities of latencies of saccades (isolated and combined with vergence); such abnormalities were attributed to deficits of fixation control and of visual attention. In this study we examine speed and accuracy characteristics of horizontal eye movements in natural space (saccades, vergence and combined movements) in dyslexic reader children. Methods. Two paradigms are tested: gap paradigm (fixation offset 200 ms prior to target onset), producing shorter latencies, in both non-dyslexic reader and dyslexic reader children and simultaneous paradigm. Seventeen dyslexic reader children (mean age: 12 +/- 0.08 years) and thirteen non-dyslexic reader children (mean age: 12 +/- 1 years) were tested. Horizontal eye movements from both eyes were recorded simultaneously by a photoelectric device (Oculometer, Dr. Bouis). Results. For all movements tested (saccades, vergence, isolated or combined) and for both paradigms, the mean velocity and accuracy were similar in dyslexic readers and non-dyslexic readers; no significant difference was found. Conclusion. This negative but important result, suggests no dysfunction of brainstem ocular motor circuits in dyslexic readers. It contrasts results on latencies related to visual attention dysfunction at cortical level.

No MeSH data available.


Related in: MedlinePlus