Visual training could be useful for improving reading capabilities in dyslexia

Abstract

The term dyslexia originated in 1887 when an ophthalmologist described the difficulty of learning to read. After more than a century of research, we still do not know the etiology of such pathology. Several hypotheses have been suggested to explain dyslexia and in the present article we will describe in detail the visual attentional deficits reported in dyslexia. Reading is a complex cognitive process during which several mechanisms are involved (visual perception, eye movements -saccades and fixations-, semantic and linguistic abilities); consequently, a deficit in one of these different components could cause impairment in reading acquisition. In children with dyslexia, we observed abnormal oculomotor patterns during reading: frequent saccades of small amplitude, long-term fixation, high number of saccades to the left (retro-saccades), and poor binocular coordination during and after the saccades. These results suggest a deficit of visual information processing as well as an immaturity of the interaction between the saccade and vergence systems. In the present review, we will discuss different methods that use short periods of visual rehabilitation or text manipulation, and by using an eye tracker in order to obtain objective information on eye movement’s performance during reading, assist in improved reading performance of dyslexic children.

Full text

Visual training could be useful for improving reading capabilities in dyslexia
Maria Pia Bucci
UMR 1141 Inserm –Paris Diderot University, Robert Debr!
e Hospital, Paris, France
ABSTRACT
The term dyslexia originated in 1887 when an ophthalmologist described the difficulty of
learning to read. After more than a century of research, we still do not know the etiology of
such pathology. Several hypotheses have been suggested to explain dyslexia and in the pre-
sent article we will describe in detail the visual attentional deficits reported in dyslexia.
Reading is a complex cognitive process during which several mechanisms are involved (vis-
ual perception, eye movements -saccades and fixations-, semantic and linguistic abilities);
consequently, a deficit in one of these different components could cause impairment in
reading acquisition. In children with dyslexia, we observed abnormal oculomotor patterns
during reading: frequent saccades of small amplitude, long-term fixation, high number of
saccades to the left (retro-saccades), and poor binocular coordination during and after the
saccades. These results suggest a deficit of visual information processing as well as an
immaturity of the interaction between the saccade and vergence systems. In the present
review, we will discuss different methods that use short periods of visual rehabilitation or
text manipulation, and by using an eye tracker in order to obtain objective information on
eye movement’s performance during reading, assist in improved reading performance of
dyslexic children.
KEYWORDS
Filters; fixations; reading;
saccades; visual training
Introduction
The term dyslexia was proposed in 1887 by Rudolf
Berlin, an ophthalmologist, who described the reading
disorder (Berlin, 1887). Dyslexia is a specific learning
difficulty in reading without compromising oral or
nonverbal reasoning skills and it affects between 5
and 15% of the school-age population (Pennington,
2009). The origin of dyslexia is still not well known; it
is a complex reading disorder involving genetic and
environmental factors (Bishop, 2015). Researchers
have suggested several theories of dyslexia and the
hypothesis of a phonological deficit in dyslexia has
been shared by several authors (Brady, Shankweiler, &
Mann, 1983; Bruck, 1992; Snowling, 1995). Recent
imaging studies reported that phonological deficien-
cies in dyslexics are correlated with important abnor-
malities in the cortical structure of the left hemisphere
(Hampson et al., 2006; Xia, Hoeft, Zhang, & Shu,
2016). Taken together, these results suggest that a
phonological theory is partially correct but that it can-
not explain all deficiencies reported in dyslexia.
Other theories have been proposed such as auditory,
visual perception, working memory, and attentional
abnormalities (Brosnan et al., 2002; Facoetti et al.,
2003; Nicolson & Fawcett, 1990; Stein, Riddell, &
Fowler, 1988; Tallal, 1980). Further functional mag-
netic resonance imaging (fMRI) studies (Demb,
Boynton, & Heeger, 1997,1998; Eden et al., 1996)
reported abnormal processing of visual motion, par-
ticularly in the extrastriate middle temporal brain
areas, supporting the hypothesis of an M-cell pathway
visual abnormality in subjects with dyslexia. Gori,
Seitz, Ronconi, Franceschini, and Facoetti (2016)
showed, with different experiments, the impairment of
the magnocellular system in dyslexia and highlighted
the role of this system in developing normal visual
capabilities. A recent work (Le Floch & Ropars, 2017)
underlined visual abnormalities in dyslexics, based on
the absence of asymmetry of the two foveas
(Maxwell’s spot centroid) that seems to play an
important role for brain connectivity in normal child
development. In relationship with the hypothesis of a
visual deficit in dyslexia, Stein (2018) advanced the
theory of an impaired dorsal stream function, even if
several researchers do not share this hypothesis and
the existence of a deficit of the dorsal pathway in
CONTACT Maria Pia Bucci mariapia.bucci@gmail.com UMR 1141 Inserm - Paris Diderot University, Robert Debr!
e Hospital, Paris, France.
Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/hapc.
!2019 Taylor & Francis Group, LLC
APPLIED NEUROPSYCHOLOGY: CHILD
https://doi.org/10.1080/21622965.2019.1646649

dyslexia is still under debate (Blythe, Kirkby, &
Liversedge, 2018).
It is important to point out that for reading, a
good control of eye movement (saccades, fixation and
vergence) is required, and several studies reported
poor eye movement control in dyslexic children inde-
pendently of language. Indeed, during reading Greek,
dyslexic children showed longer and increased num-
bers of fixations, pro-saccades with shorter amplitude,
and frequent retro-saccades (Palvidis, 1981), suggest-
ing that such oculomotor abnormalities could be
responsible for slow-reading abilities in these children.
Successively, a similar abnormal oculomotor pattern
has also been reported in English (Rayner, 1985),
Italian (De Luca, Di Pace, Judica, Spinelli, &
Zoccoloti, 1999), German (Trauzettel-Klosinski et al.,
2010), Chinese (Li et al., 2009), and French (Seassau,
Gerard, Bui-Quoc, & Bucci, 2014) dyslexic children.
Furthermore, our group (Bucci, Nassibi, Gerard, Bui-
Quoc, & Seassau, 2012; Tiadi, Gerard, Peyre, Bui-
Quoc, & Bucci, 2016) suggested a deficiency in the
visual attentional processing, as well as an immaturity
in the interaction between the saccade and the ver-
gence system, leading to poor motor control during
reading by French dyslexic children. Note, however,
that it is not yet clear whether atypical eye movement
performance is the cause or the consequence of read-
ing difficulties in dyslexia. Independently of the fact
that visuo-oculomotor problems observed in dyslexics
are the result or the cause of their reading problems,
several studies have been performed to test the possi-
bility of improving reading capabilities in the dyslexia
population via “visual training.”Indeed, by perform-
ing a PubMed research, one can find about 363 papers
focused on “visual training in dyslexia,”suggesting
that this research issue is important and it has great
interest for scientists.
Recently, Peters and collaborators (Peters, De Losa,
Bavin, & Crewther, 2019) reviewed the effect of sev-
eral types of visuo-attentional interventions for read-
ing in dyslexic children; however, they did not
describe studies in which eye movements were
recorded during reading. Next, we will describe new
studies on rehabilitation techniques that reduce read-
ing deficits in dyslexia that are relevant to studies
dealing with eye movements in dyslexia.
A study done in 2012 (Chouake, Levy, Javitt, &
Lavidor, 2012) reported that basic visual networks,
such as the magnocellular system, might play a crucial
role in reading deficits observed in dyslexia. These
researchers showed that reading abilities significantly
improved in dyslexics after five days of training using
a motion detection task (magnocellular training); in
contrast, dyslexics trained with a control task of pat-
tern detection (parvocellular training) did not showed
any reading improvement. This study advanced the
importance of basic visual systems in reading and had
potential implications for reading rehabilitation in the
dyslexic population. In the same line of thinking,
Ebrahimi, Pouretemad, Khatibi, and Stein (2019)
explored the effect of magnocellular based visual
motion training on reading performance in Persian
speaking dyslexic children. The training consisted on
12 sessions, twice a week over 6 weeks. They found an
improvement of reading capabilities that persisted also
after training (at least 1 month later). The authors
advanced the hypothesis that a simple test on magno-
cellular function could be also used as screening tool
for detecting dyslexia early before that child starts
to read.
It has been also shown that several dyslexics suffer
from crowding phenomenon, that is, impaired recog-
nition of the word due to the presence of neighboring
letters (Bouma, 1970) and dyslexics could take advan-
tage of reading a text with larger spaced letters (Zorzi
et al., 2012).
Meng, Lin, Wang, Jiang, and Song (2014) also
reported that visual perceptual training can improve
reading performance in Chinese children and that
such improvement persisted for up to 2 months, sug-
gesting that visual perceptual processing and reading
ability could, at least partially, rely on overlapping
mechanisms. Gori and Facoetti (2014) also reported
that perceptual learning could improve visual capabil-
ities in dyslexic children that are the consequence of a
magnocellular impairment and poor visual attention,
given that as suggested by Rizzolatti, Riggio, Dascola,
and Umilt!
a(1987), there is a relationship among vis-
ual input, eye movement, and attention. Furthermore,
it has been also explored whether playing action video
games (without reading or phonological content)
could improve reading abilities in dyslexia
(Franceschini et al., 2013,2017). These authors
reported that 12 hours of playing action video games
(AVG), in contrast to nonaction video games
(NAVG), significantly improved the reading abilities
in French dyslexic children (Franceschini et al., 2013)
as well as English dyslexic children (Franceschini
et al., 2017). The AVGs have specific characteristics:
“1) extraordinary speed both in terms of very transi-
ent events and in terms of the velocity of moving
objects; 2) a high degree of perceptual, cognitive, and
motor load in the service of an accurate motor plan;
3) unpredictability both temporal and spatial; 4) an
2 M. P. BUCCI

emphasis on peripheral processing (Green, Li, &
Bavelier, 2010, page 203). Based on the description of
the AVG characteristics, a possible distinction between
the two treatments could be that the AVG increase
stimulation of the Magnocellular-Dorsal or Action
stream in comparison with the NAVG (Vidyasagar &
Pammer, 2010). Recently, Franceschini and Bertoni
(2018) reported that AVG intervention in dyslexic
children improved both phonological decoding speed
and phonological short-term memory. Note, however,
that such improvement has been reported in a small
group of dyslexic Italian children that obtained a good
video game score.
Finally, the possible benefits of reading text
through colored filters have also been suggested to
facilitate reading in dyslexia, even if it is an extremely
controversial subject (see the review of Uccula, Enna,
& Mulatti, 2014, and more recent Stein, 2018). For
instance, Ritchie, Sala, and McIntosh (2011) failed to
show a significant effect of colored filters on reading
performance in dyslexia population and Denton and
Meindl (2016) did not report either significant
improvements in reading from the use of colored fil-
ters in three individuals with dyslexia (7-, 11-, and 32-
year-old). In contrast, Ray, Fowler, and Stein (2005)
showed reading improvement after yellow filters used
for 3 months compared with the use of no filter in
children with reading difficulties. Those authors sug-
gested that the yellow color increased input to the
magnocellular system by selectively stimulating both
L- and M-cones. One major problem with studies
exploring the colored filter effect during reading is the
lack of standardization during the trials. For example,
the procedures used to investigate reading perform-
ance with and without filters should be strictly con-
trolled, such as maintaining the same experimental
setup; preventing any noise and/or distractions; ran-
domizing the trials with and without filters; and, most
importantly, presenting different texts in each condi-
tion to prevent learning effects. Finally, it is important
to record eye movements during the reading with fil-
ters in order to obtain objective data on eye move-
ment. Based on these findings, the current study
further explores the effect of colored filters on reading
performance in dyslexic and nondyslexic children.
The following sections describe some recent studies
made by our group in which we explored some tech-
niques to improve reading performance in dyslexic
children. Eye movements were recorded during read-
ing text in order to objectively quantify the eventual
benefit of these rehabilitations.
Children population
Dyslexic children participated in the studies were
recruited from the Center for Language Disorders and
Learning, at the Robert Debr!
e pediatric hospital
(Paris), to which they had been referred for a com-
plete evaluation of their dyslexia including an exten-
sive examination of their neurological/psychological
and phonological capabilities. For each child, we
measured the time they required to read a text pas-
sage, assessed their general text comprehension, and
evaluated their ability to read words and pseudo-
words using the L2MA battery (oral Language, written
Language, Memory, Attention; Chevrie-Muller, Simon,
& Fournier, 1997). This is the standard test in France
developed by the “Center de Psychologie appliqu!
ee de
Paris”and is used to detect dyslexic populations.
Inclusion criteria were: score on the L2MA thhat was
more than two standard deviations from the mean, a
normal mean intelligence quotient (IQ, evaluated
using the Wechsler Intelligence Scale for Children-
Fourth edition [WISC-IV], 2004), namely between 85
and 115 and normal visual acuity at near vision (both
eyes !10/10). The reading age of all children was
assessed using the ELFE test (www.cognisciences.com,
Grenoble). Children with comorbid diagnosis such as
ADHD and dyslexia were not included in our studies.
Typically developing (TD) age-matched children
group was compared to dyslexic group. The inclusion
criteria for TD children were as follows: no known
neurological or psychiatric abnormalities, no history
of reading difficulty (reading score was assessed by
ELFE test), no visual impairment, or difficulty with
near vision. Also, IQ in TD children was estimated on
two subtests, one assessing their verbal capability
(similarities test) and one assessing their logic capabil-
ity (matrix reasoning test). Normal range for both
tests is 10 ± 3 (WISC-IV). The number and the age of
the population participating in each of the studies are
reported in the following section.
Eye movement recording during reading text
We used an eye tracker (Mobile EBT, from
e(ye)BRAIN, SuriCog, Paris, France), to record eye
movements from both eyes. This system is a CE-
marked medical eye- tracking device (Figure 1); its
frequency is 300 Hz and its precision is 0.25".
Children were asked to read a text of four lines
from a children’s book projected on a PC screen at
60 cm in front of the child. The text consisted of 40
words and 174 characters, it was 29"wide and 6.4"
high and the mean character width was 0.5". The
APPLIED NEUROPSYCHOLOGY: CHILD 3

words were written on a white background in black
“courier”font. During reading, eye movements were
recorded at the same time; for oculomotor data, cali-
bration factors for each eye were determined from the
eye positions during a calibration procedure done
before the reading task. The number and the ampli-
tude of progressive saccades (pro-saccades, from left
to right) and regressive saccades (retro-saccades, from
right to left) and the duration of fixations between
each saccade were analyzed. The time to perform
reading task was also measured.
Statistical analysis
Analysis of variance (ANOVA) was performed in the
two groups of children (dyslexic and TD children) on
the different oculomotor parameters. The level of sig-
nificance was maintained at 0.05.
Effect of green filters
Further exploration of the effect of filters on reading
performance in dyslexic children was deemed import-
ant, based on the work of Irlen (1983) who patented a
set of colored-filter lenses for visual stress treatment,
which is linked to problems of seeing a distorted page
of words or perceiving the environment in a distorted
fashion. Such visual difficulties (also called Meares-
Irlen syndrome) can affect reading, writing, spelling,
math, copying, reading music, working on a com-
puter, night driving, driving, sports performance, and
comfort under fluorescent lights, among other effects.
However, the use of colored-filtered lenses to reduce
the effects of visual stress on reading is controversial,
and the scientific community remains skeptical about
their benefits.
In one study (Razuk et al., 2018), we recorded eye
movements while 18 dyslexic (mean age
9.8 ± 1.2 years) and 18 IQ- and age-matched nondy-
slexic children read different texts (with similar diffi-
culties) in three different filter conditions: no filter,
yellow filter, and green filter. We reported that the
total reading time and the duration of fixations, which
were significantly longer in dyslexic versus TD chil-
dren while reading without filters, significantly short-
ened in dyslexic children only when they were reading
with green filters on (see Figure 2A and B), respect-
ively), suggesting that visual word recognition/
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700
No filters Yellow filters Green filters
dyslexics
Non-dyslexics
0
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15
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(A)
No filters Yellow filters Green filters
dyslexics
Non-dyslexics
Total reading !me (sec) (B) Dura!on of fixa!ons (msec)
*
* *
*
Figure 2. Mean of the total reading time (A) and of the duration of fixations (B), while reading without filters and with yellow
and green filters for dyslexic and nondyslexic children. Vertical bars indicate the standard error. Horizontal bars indicate significant
difference in dyslexic groups.
Figure 1. Mobile Eyebrain tracker used to record
eye movements.
4 M. P. BUCCI

identification was facilitated by changing the color of
the visual stimulus. In contrast, in TD children, filters
did not affect these parameters (i.e., reading time and
the duration of fixation).
The results of this study indicated no significant
discrepancies in the number of pro- and retro-
saccades across the visual conditions. These results
may suggest that the oculomotor pattern of children
with dyslexia, which consists of smaller and more fre-
quent pro- and retro-saccades, could be due to a
reduced visual attention window (Friederici,
R€
uschemeyer, Hahne, & Fiebach, 2003) and that nei-
ther the green nor the yellow filter was sufficient to
change and improve such abnormal behavior. We
suggest that colored filters minimize the distortions
and apparent text motion and that they could be con-
sidered useful as assistive technology for people with
learning disabilities according to previous studies
(Hall, Ray, Harries, & Stein, 2013; Henderson, Tsogka,
& Snowling, 2013). Interestingly, an imaging study
(Kim, Seo, Ha, & Kim, 2015) investigated sentence
reading before and after the use of color filters in
patients with Meares-Irlen syndrome. The results
showed that 20% of patients wearing blue filters
improved their reading speed. Moreover, the fMRI
showed that the activity of the left middle and super-
ior temporal cortices significantly increased while
reading with filters compared to sentence reading
without filters. Recall these regions are involved in
comprehension and, more specifically, semantic and
syntactic integration; thus, despite the controversy, the
use of filters seems to change activation in cortical
structures related to the reading process. This finding
is interesting and definitely indicates the need for
more studies to confirm the benefits of colored filters
on the reading performance in dyslexic children.
Although many questions and doubts remain, our
study suggests that green filters can be used as an
additional tool at school and home to improve the
academic performance of children with dyslexia.
Effect of font sizes and of spaces between words
The goal of the study by Masulli et al. (2018) was to
explore the eventual change in eye movements per-
formance in a group of 15 dyslexic (mean age:
9.4 ± 0.2 years) and 15 IQ- and age-matched nondy-
slexic children reading a text with different font sizes
and spaces between the words. As previously men-
tioned in the Introduction, the crowding effect in dys-
lexic subjects can be reduced by adding space between
letters (Bouma & Legein, 1977). Interestingly, spacing
between the words influences word comprehension
and oculomotor performances (Slattery & Rayner,
2013), but, in contrast to the previous findings (Zorzi
et al., 2012), for some researchers such improvement
is also observed among nondyslexic subjects (Skotun
& Skoyles, 2012). Indeed, several other studies
observed a reading improvement in terms of speed or
accuracy that was not specific to individuals with dys-
lexia only (Hakvoort, van den Boer, Leenaars, Bos, &
Tijms, 2017; Perea & Gomez, 2012). In order to gain
more insight on the effect of different sizes and
spaced words on reading we recorded objectively eye
movements in dyslexic and nondyslexic children dur-
ing reading three different texts with different corpus
and/or inter-letter space (Text 1: Corpus: 25 pt; Inter-
letter space: 1 pt; Text 2: Corpus: 25 pt; Inter-letter
space: 2.5 pt; Text 3: Corpus: 30 pt; Inter-letter space:
2.5 pt). The child was asked to read aloud in order to
register the number of errors he/she made; after read-
ing each text we asked few questions to the child to
assess he/she text comprehension.
We reported that increasing font size and character
spacing changed eye movement’s performance. In
more detail, the duration of the fixations (Figure 3A),
independently to the text read, was significantly longer
in dyslexic than in TD children, but in dyslexic group
it reduced significantly while reading Text 2 and 3.
The number of pro-saccades (Figure 3B) in all three
types of text was significantly larger in dyslexic than
in TD children group, but it increased with the
increase of the font size and space between the words.
Note that this occurred also for TD children. Finally,
the amplitude of pro-saccades (Figure 3C) was similar
between the two groups of children, but it increased
significantly while reading Text 2 and 3 for both
groups of children (dyslexics as well as TD).
Taken together, these results suggest that the size
and the interspace of the letters of a text can affect
oculomotor pattern: the duration of fixations, the
number, and the amplitude of pro-saccades changed
depending of the type of the text read.
Finally, the total duration for reading the text
was not affected by the type of the text read.
Reading a text in which the size and the interspace
of the letters increased facilitates reading capabilities,
even if the total time for reading did not change
given that even if the duration of fixation is short-
ened, the child make several saccades of large amp-
litude. It should be noted that the three texts were
balanced in terms of number and length of words
and that they differed only in font size and letter
spacing. Consequently, the greater number of
APPLIED NEUROPSYCHOLOGY: CHILD 5

pro-saccades made by both groups of children while
reading Texts 2 and 3, with respect to the Text 1
could be due to the typographical characteristics.
Indeed, larger font size led the child to make more
saccades in order to look at the word of interest
and to put it on the fovea. By increasing both letter
size and interletter spaces, the crowding effect could
also be reduced, which leads to a better reading
performance in both groups of children, most likely
due to visual attention capabilities that play an
important role in phonological decoding.
Even if this study did not directly test a visual
reeducation technic for improving reading in dys-
lexic children, the present findings could be useful
for the facilitation of reading in such a population.
Indeed, based on these results, we could develop
applications on tablets or e-readers that allow text
size changes and other features that help dyslexic
(and nondyslexic) children ameliorate their reading
performance.
Effect of computer based oculomotor training
Finally, based on the hypothesis of eye movements
difficulties in dyslexia, we aimed at validating a com-
puter-based program for remediation of reading defi-
cits in French (Peyre et al., 2018) and Italian dyslexic
children (Bucci, Carzola, Fiucci, Potente, & Caruso,
2018). The training used in these two studies consists
of four different exercises (rapid naming task, Stroop
task, motion perception and saccades) performed
15 minutes a day, 5 days a week, for 8 weeks. In
France, we conducted a crossover randomized trial on
11 children (from 7 to 12 years old); participants were
assessed on reading and writing skills as well as
phonological skills, visuo-attentional skills, and verbal
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Text 1 Text 2 Text 3
dyslexics
Non-dyslexics
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Text 1 Text 2 Text 3
dyslexics
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Text 1 Text 2 Text 3
dyslexics
Non-dyslexics
*
*
*
*
*
*
(A) Dura!on of fixa!ons (sec)
(C) Amplitude of pro-saccades (deg)
(B) Number of pro-saccades
Figure 3. The mean of duration of the fixations (A), of the number (B), and of the amplitude (C) of pro-saccades in both groups
of children tested (dyslexic and nondyslexic), while reading the three different types of text (Text 1: 25 pt with 1 pt inter-letter;
Text 2: 25 pt with 2.5 inter-letter; Text 3: 30pt with 2.5 pt inter-letter). Vertical bars indicate the standard error. Horizontal bars
indicate significant differences.
6 M. P. BUCCI

memory using the French Batterie Analytique du
Langage Ecrit (BALE). Eye movements during reading
a text were recorded before and after training. French
dyslexic children did not show effects of training on
reading capabilities. However, after training they
showed a significant improvement on several tests
measuring phonological skills (syllabic suppression),
visuo-attentional skills (search of anarchic verbal
cues), verbal memory (digit span backward), and writ-
ing skills (regular words). The same study was than
conducted on a group of 16 Italian dyslexic children
(mean age: 10.2 ± 0.3 years), but with an important
difference with respect to the study previously per-
formed: each of the four exercises was composed of
eight levels with increasing difficulty, developed using
the Unity game engine (Unity Technologies, Paris,
France). After the training, we observed that the
majority of dyslexic children (69%) significantly
improved the number of syllables read per second.
Moreover, as shown in Figure 4, the total time of
reading (4A) and the duration of fixations (4B) sig-
nificantly decreased after training (in 77% of children
tested). These results are interesting, even if they need
to be confirmed by a study comparing a population of
dyslexic and nondyslexic children. Additionally, a fol-
low-up study will be necessary in order to verify the
permanence of the beneficial effect of training in read-
ing capabilities.
Such training benefits suggest that a computer-
based oculomotor program could be an easy and prac-
tical tool for improving reading performance in dys-
lexic children. The based oculomotor rehabilitation
proposed in this study allowed to train visuo-
attentional capacities as well magnocellular abilities.
We suggest that both mechanisms occur given that
visuo-attention and saccades are strictly linked to each
other and that the magnocellular visual pathway is
also involved in oculomotor performance (Leigh &
Zee, 2015).
Finally, an important point to be discussed is the
individual home training performance follow-up used
in this study. Indeed, to the best of our knowledge,
this is the first time that a training performed at
home is controlled and supervised, and user perform-
ance continuous monitoring is an important step in
the development of training programs. Indeed, chil-
dren with unsatisfactory performance in different lev-
els of each one of the four exercises did not present a
shortening in fixations. This finding is in line with the
study of Franceschini and Bertoni (2018) showing that
only children who performed well in the video games
training obtained a significant improvement in read-
ing, highlighting the importance of training supervi-
sion by the clinician and/or therapist. Further
research on such issues will be necessary to confirm
these previous findings; however, a computerized
oculomotor training could be helpful for improving
reading capabilities in dyslexic children.
General discussion
For several years, researchers posited that a phono-
logical deficit is the mean cause of dyslexia (Peterson
& Pennington, 2012). However, it is well known that
when one child is reading a word, he/she needs to
have good fixation and correct position of the visual
axis on the word that is read. Consequently, the eye
movement’s capability that in dyslexia is known to be
impaired needs to be considered independently of lan-
guage (Bucci et al., 2012; De Luca et al., 1999;
Li et al., 2009; Palvidis, 1981; Rayner, 1985; Seassau
et al., 2014; Tiadi et al., 2016; Trauzettel-Klosinski
0
10
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60
70
80
Before training A"er training
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400
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700
Before training A"er training
Dura!on of fixa!ons (msec)Total reading !me (sec)
*
*
(A) (B)
Figure 4. Total time of reading (A) and the duration of fixations (B) in dyslexic children tested before and after training. Vertical
bars indicate the standard error. Horizontal bars indicate significant difference.
APPLIED NEUROPSYCHOLOGY: CHILD 7

et al., 2010). Several studies previously cited confirmed
the hypothesis of a visual deficit in dyslexia in rela-
tionship with poor magnocellular system organization
and difficulty to focalize visual attention (see review
of Stein (2018)). Our studies are in line with this
hypothesis, because their goal was to test new visual
attentional techniques in order to improve reading
abilities in dyslexic children. Indeed, the use of filters
for reading, and/or the use of larger letter size and
interletter spaces, could improve the magnocellular
activity leading to a better visual input at the cortical
level for better and faster word identification. The
new computer-based oculomotor program tested was
created to improve visual attention span, as well as
oculomotor and magnocellular performance in dys-
lexia as these mechanisms have also been shown to be
impaired in subjects with dyslexia (Bosse, Tainturier,
& Valdois, 2007; Eden, Stein, Wood, & Wood, 1994;
Gori et al., 2016 Valdois, Bosse, & Tainturier, 2004).
Conclusion
Taken together, these results suggest dyslexic children
could benefit from visual oculomotor training to
improve their reading capabilities. Further studies are
necessary to be performed in order to confirm such
findings on a large population of dyslexic children
from different countries. Also important is the use of
an eye tracker, which allows precise and objective
quantification of reading improvement after training,
with precise information on oculomotor patterns dur-
ing reading and not only the reading performance of
children. Finally, several types of dyslexia exist, and it
is not yet well known the role of visual, attentional,
phonological, and auditory deficiencies in such path-
ology. A focus on training that deals with these defi-
cits will be useful for dyslexic children.
Statement of ethics
The investigation adhered to the principles of the
Declaration of Helsinki and was approved by the
Institutional Human Experimentation Committee of
CPP Ile de France I (Hotel-Dieu Hospital).
Acknowledgments
The authors are particularly grateful for the cooperation of
the Child and Adolescent Psychiatry Department, Robert
Debre Hospital (Paris) for permitting the testing of dys-
lexic children.
Disclosure statement
The authors declare no competing interests exist.
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