© Freund Publishing House Ltd.

Int J Adolesc Med Health 2010;22(2):273-281

The effect of hemisphere specific remediation
strategies on the academic performance outcome of
children with ADD/ADHD
Gerry Leisman, MD, PhD1,2, Robert Melillo, DC, MSc1,3, Sharon Thum, MSc1,3, Mark
A Ransom, MSc1, Michael Orlando, DC1, Christopher Tice, DC1 and Frederick R
Carrick, DC, PhD4
1

The FR Carrick Institute for Clinical Ergonomics, Rehabilitation and Applied
Neuroscience, Mineola, New York, USA; 2University of Haifa, Israel; 3Department of
Psychology, DeMontfort University, United Kingdom; 4Carrick Institute for Graduate
Studies, Cape Canaveral, Florida, USA
Abstract: The development and normal function of the cerebrum is largely dependent on sub-cortical
structures, such as the cerebellum and basal ganglia. Dysfunction in these areas can affect both the
nonspecific arousal system and information transfer in the brain. Dysfunction of this sort often results
in motor and sensory symptoms commonly seen in children with ADD/ADHD. These brain regions
have been reported to be underactive, with that underactivity restricted to the right or left side of the
sub-cortical and cortical regions. An imbalance of activity or arousal of one side of the cortex can
result in a functional disconnection similar to that seen in split-brain patients. Since ADD/ADHD
children exhibit deficient performance on tests thought to measure perceptual laterality, evidence of
weak laterality or failure to develop laterality has been found across various modalities (auditory,
visual, tactile) resulting in abnormal cerebral organization and associated dysfunctional specialization
needed for lateralized processing of language and non-language function. This study examines groups
of ADD/ADHD elementary school children from first through sixth grade. All participants were
administered all the subtests of the Wechsler Individual Achievement Tests, the Brown Parent
Questionnaire, and given objective performance measures on tests of motor and sensory coordinative
abilities (interactive metronome). Results measured after a 12-week remediation program aimed at
increasing the activity of the hypothesized underactive right hemisphere function, yielded significant
improvement of greater than two years in grade level in all domains except in mathematical
reasoning. Results are discussed in the context of the concept of functional disconnectivity in
ADD/ADHD children.
Keywords: Attention deficit hyperactivity disorder, hemispheric function, rehabilitation, synchronized
metronome
Correspondence: Gerry Leisman, CERAN, 647 Franklin Avenue, Garden City, New York, 11530
United States. E-mail: drgersh@yahoo.com
Submitted: December 20, 2009. Revised: January 15, 2010. Accepted: January 20, 2010.
INTRODUCTION

Attention-deficit/hyperactivity
disorder
(ADHD) is the most common neuro-

behavioral disorder of childhood. ADHD is
also among the most prevalent chronic
health conditions affecting school-aged

 274

UNDERACTIVE HEMISPHERIC FUNCTION IN ADD

children. The core symptoms of ADHD
include inattention, hyperactivity, and
impulsivity (1,2). Children with ADHD
may experience significant functional
problems, such as school difficulties,
academic underachievement (1), troublesome interpersonal relationships with
family members (3) and peers, and low
self-esteem. Individuals with ADHD
present in childhood and may continue to
show symptoms as they enter adolescence
(4,5) and adult life (6-9).
Most of the development and normal
function of the cerebrum is dependent on
subcortical structures, especially the cerebellum and basal ganglia. A failure to
develop or a dysfunction in these areas or
both can affect the nonspecific arousal
system as well as specific transfer of
information in the brain. Dysfunction in
these areas will usually result in specific
motor and sensory symptoms that are
commonly seen in children with cognitive
or behavioral disorders, especially ADD
(Attention Deficit Disorder) and ADHD.
We have demonstrated elsewhere that these
brain regions are often seen to be
underactive in these children, based on
electrophysiological coherence studies
(2,10,11). These cortical loci have been
shown to be connected with the prefrontal
cortex, which have also often been noted to
be
underactive
in
children
with
neurobehavioral developmental disorders
(1). The underactivity and or atrophy is
usually restricted either to the right or to the
left side of the sub-cortex and cortex (1).
An imbalance of activity or arousal of
one side of the cortex or the other can result
in a functional disconnection syndrome,
similar to what is seen in split-brain patients
and early reported by Leisman (12-14) and
Sroka and colleagues (15). This could be an
underlying source of many if not all of the
symptoms that we see with children with
behavioral and cognitive disorders. For

example, post-mortem examinations have
indicated structural differences between the
brains of good and impaired readers. High
concentrations of micro-dysgenesis have
been noted in the left temporoparietal
regions
of
dyslexic
brains.
The
concentration is most evidenced in the
planum temporale region (16-18). These
micro-dysgeneses seriously impair the
normal pattern of architecture of dyslexics
and remove the asymmetry normally
observed between the enlarged language
areas of the left temporoparietal region and
the smaller homologous areas of the right
hemisphere (13,16). Our studies alluded to
earlier show such effects in ADD/ADHD
individuals.
The capacity for language is generally
correlated with a significant development in
the magnitude of the left temporoparietal
region and an attrition of neurons in the
right hemisphere. These neuronal casualties
may produce the observed asymmetry
between corresponding areas in the left and
right hemispheres (13,14,19). The relative
symmetry in the dyslexics’ brains might
reflect their impaired linguistic development, and the asymmetry in ADD/ADHD
may likewise underlie those disorders.
As Orton (20) indicated, it is generally
assumed that persons with ADD and
ADHD have abnormal cerebral organization
including atypical or weak patterns of
hemisphere specialization (21,22). The
developmental lag hypothesis proposed by
Lenneberg (23) suggested that such children
are slower to develop basic language skills
and demonstrate weak hemispheric
specialization for language tasks, including
reading. In a reformulation of the
progressive lateralization hypothesis (24), it
may be that subcortical and antero-posterior
progressions have a differential developmental course with ADD/ADHD children
and adults compared with control subjects
or those with acquired syndromes.

 G LEISMAN ET AL

Because ADD/ADHD children exhibit
deficient performance on a variety of tests
thought to be a measure of perceptual
laterality, evidence of weak laterality or
failure to develop laterality has been found
across various modalities (audio, visual,
tactile) (25). These children are thought to
have abnormal cerebral organization, as
suggested by Corballis (22). The basic
assumption is that dysfunction in the central
nervous system, either prenatally or during
early postnatal development, results in
abnormal cerebral organization and the
associated dysfunctional specialization
needed for lateralized processing of
language function and non-language skills.
It is thought that cortical and subcortical
dysfunction resulting from aberrant patterns
of activation or arousal (25), inter- and
intra-hemispheric transmission deficits,
inadequate resource allocation (26), or any
combination of these may compromise
hemispheric specialization in those with
cognitive and behavioral deficits (22).
Rabiner and Malone (27) has indicated
that children with learning problems
associated with ADD/ADHD can acquire at
least grade-level reading skills if such
children receive early intensive intervention
to correct their deficiencies (28,29). The comorbidity of ADD/ADHD and reading
difficulties described earlier justifies the
examination and evaluation of remedial
strategies for cognitive tasks in ADHD
children that are hemisphere specific. To
examine this notion further, we conducted a
pilot study evaluating ADD/ADHD
elementary school children from first
through sixth grade. All participants were
administered tests of academic performance
evaluating relevant cognitive abilities,
motor and coordinative, and rudimentary
literacy skills. ADD/ADHD children were
tested both before and after participation in
a hemisphere specific remediation program.

275

METHODS

The pool of participants for this study
consisted of 122 children between 6-12.11
years of age diagnosed with Attention
Deficit Disorder (ADD) or Attention
Deficit Hyperactivity Disorder (ADHD).
The participants presented with inattention,
hyperactivity, impulsivity, academic underachievement, and/or behavior problems,
and each met the criteria of the Diagnostic
and Statistical Manual of Mental Disorders,
Fourth Edition, and clearly demonstrated
the absence of coexisting conditions as
evaluated by non-participating licensed
Psychologists
or
Psychiatrists.
The
participating children came from clinics
associated with one of the authors located
in school districts in middle- to uppermiddle-class school districts in Nassau and
Suffolk Counties, New York. Of the total
participants, 94 (77%) were male and 28
(23%) female. All were in the average
range of intellectual ability as measured by
standardized tests of intelligence (data not
herein reported). Parental informed consent
was obtained. The exclusionary criteria
included (a) severe vision or hearing
problems, (b) frequent ear infections,
(c) severe emotional problems, (d) limited
intellectual ability, (f) English as a second
language, and (g) diagnosed Pervasive
Developmental Disorder. All children in the
study were taking stimulant medication
before, during, and at the conclusion of the
study. No changes in pharmacological
management occurred during the course of
the trial for any of the participants. Formal
testing employing the BADD (30), see
below) was 100 percent concordant with
the diagnosis of ADD/ADHD that each
participant had received elsewhere before
entry into the study.
Procedure
Initial pre-treatment evaluations included

 276

UNDERACTIVE HEMISPHERIC FUNCTION IN ADD

the functional assessments of sensory and
motor function and on a separate day,
academic testing as described below. The
combined testing allowed the clinicians to
formulate a treatment program that was
designed to selectively stimulate the skills
that were significantly below age-or
functional level for a given participant, and
were aimed nominally at exercises thought
to principally stimulate the less efficiently
performing hemisphere. Each participant
participated in this multi-modal program
three times per week for one hour each time
over a twelve-week period.
Each participant underwent specific
supervised activities during that time that
included: sensory stimulation, motor
training, aerobic strength and conditioning,
and academic training. Compliance with the
regimen was achieved with most but not all
participants. Also employed in the regimen
were primitive reflex inhibition exercises,
as well as academic home training exercises.
After 36 sessions over a 12-week period,
participants were again tested on the same
battery of tests of sensory, motor, and
academic performance, including the
completion of the parent behavioral
checklist. The academic testing was
performed by the same individual during
both the pre- and post-treatment sessions.
The treatment attempted to achieve a
temporal coherence between large cortical
networks on the left and right hemispheres
and to increase all functions in that
hemisphere that were functionally deficient.
The idea was to achieve an evenness of
skills that would be at or above the child’s
actual age and or grade level.
Synchronized Metronome Treatment
(SMT) was employed. Participants wore a
headphone and listened to a reoccurring
metronomic beat. As they listened to the
beat, they engaged in physical movements
such as clapping hand-to-hand with a
sensor on one palm as they matched their

physical movement to the presentation of
the beat (e.g., clap at the beat). The training
attempted to reduce the mean negative
synchronization error during normal
tracking of the regularly occurring metronome beat (clapping before or past the
beat). During training, participants received
feedback through an auditory guidance
system as they progressed through the
simple, interactive physical movements.
Although feedback was also provided
through visual stimuli, the auditory
feedback guidance system was the primary
feedback method. The auditory feedback
system provided tonal stimuli that indicated
whether the participant responded before,
at, or past the regularly occurring auditory
metronomic beat. The accuracy of
participants’ expectancy response to the
metronome beat was provided in
milliseconds (ms), with different tones
indicating far from, close to, or at the
metronome beat. A visual reading of
millisecond latency was also presented to
the participants on a computer screen.
The purpose of the training was to
improve participants’ timing/rhythmicity by
reducing the latency between the onset of
the metronome beat and the participant’s
expectancy response to the beat. At the
completion of the treatment program,
participants had engaged in approximately
25,000 motoric repetitions. The purpose of
the procedure was to examine the
relationship between improvements in
domain-specific SMT-based intervention
and domain general improvements in the
areas of academics and ADD/ADHD
functioning—more fully explained in (1).
All participating children were given the
Wechsler Individual Achievement Tests
[WIAT-II] (31), including Word Reading,
Reading Comprehension, Mathematical
Reasoning, Spelling, Written, Expression,
Listening Comprehension, and Oral subtests.
All subtests were given immediately before

 G LEISMAN ET AL

the participants’ start in the program and
again at the conclusion of the 12-week
hemisphere-specific intervention program.
Additionally, all participants were given the
Brown Attention Deficit Disorder Scales
(BADD) (30) that was appropriate for each
participant’s age, both before and after the
12-week intervention program.
The 122 participant children were
selected from a larger group of 181 children
undergoing the treatment program; 59 were
excluded for reasons indicated above. A
control group of untreated children was not
included for comparison purposes for this
pilot study. At the conclusion of the 12week intervention program, all children
were tested again using the same
instruments. All the obtained percentile
scores were converted to grade equivalent.
These WIAT reading tasks were chosen
because they require the ability of the
participant to correctly read a series of
printed words, sentences, and paragraphs
and to answer questions about what was
read and to correctly apply phonetic
decoding rules when reading a series of
nonsense words.
The Mathematical Reasoning Subtest of
the WIAT was chosen because it assesses
the ability of the participants to add,
subtract, multiply, and divide one- to threedigit numbers and to understand number,
consumer math concepts, geometric
measurement, basic graphs, and solve onestep word problems.
The Spelling (Written Language) subtest
was chosen because it requires the
participants to correctly spell verbally
presented words and to generate words
within a category, generate sentences to
describe visual cues, combine sentences,
and compose an organized paragraph. This
subtest likely measures skills less related to
attentional concerns and more to a direct
measure of achievement.
The WIAT Oral Language subtest was

277

chosen as the tasks require the participants
to identify a picture best representing an
orally presented descriptor or to generate a
word that matches the picture and to
generate words within a category, to
describe scenes and give directions.
Whereas IQ subtests are largely tests of
thinking and reasoning skills, the WIAT-II
is a test of academic achievement. We were
interested in examining whether hemispheric specific training would have an
effect on unmasking the actual level of
achievement with reduced attentional
effects and whether we could conclude that
the evidence is enough to warrant a clinical
trial on the notion of hemisphere-specific
training.
Statistical analyses
Pre-Post treatment differences
examined by using correlated t tests.

were

RESULTS

The results indicate significant differences
(t = 5.25, df = 60, p < .000005) between
pre- and post-treatment responses by
parents of the ADHD children. Indeed, 81%
of the participants demonstrated a
significant improve ment on pre- as
compared with post- testing (see table 1).
Pre-post
sensory-motor
measured
performance changes were likewise
significant. Rhythmic integrated eye-hand
and eye-foot coordination revealed that in
excess of 87 percent of those ADD/ADHD
children tested demonstrated statistically
significant improvement (t = 74.71, df = 97,
p < .000001).
In the measurement of academic
performance on subtests of the WIAT, the
results indicate significant changes in all
domains measured that required a strong
attentional component to test performance.
Tasks like Mathematical Reasoning, which
require greater academic skill and less
attentional focus, were more resistant to

 278

UNDERACTIVE HEMISPHERIC FUNCTION IN ADD

change. For example, on the WIAT Word
Reading subtest, 84% of participants
demonstrated a significant improvement,
Table 1. Results from pre- and post-testing

defined for this study as greater than two
years improvement in grade level (t = 2.94,

Pre-Testing

Test

%†

Post-Testing

Change

N

M

∂

N

M

∂

t

p

Brown

60

67.11

16.87

60

53.42

16.02

5.25

.000005

.81

IM

97

194.44

1.42

97

89.84

0.96

74.71 .000001

.87

Word Reading

38

3.34

2.75

38

5.31

3.2

2.94

.01

.84

Math Reasoning

122

3.2

48.06 122

5.6

5.67

0.55

**

.81

Spelling

119

3.2

3.36

119

5.6

2.85

4.07

.0005

.57

Written
Expression

119

2.8

3.16

119

5.8

3.3

17.64 .000001

.76

Listening
Comp.

121

3.2

17.31 121

6.1

2.74

8.52

.000001

.82

Oral

117

2.7

3.02

6.1

4.05

10.62 .000001

.71

WIAT

†

117

change > 2 grade levels within the 12-week program; **Not significant

df = 38, p < .01) but no significant
differences between pre- and post-testing
were observed with WIAT Mathematical
Reasoning (t = .55, df = 122, NS).
On the other hand, although 52% and
76% of participants exhibited significant
change of greater than two or more years
increase in performance after the 12-week
treatment program in Spelling (t = .0005,
df = 119, p < .0005) and Written Expression
(t = 17.64, df = 119, p < .000001), respectively, a significant 82% positive change was
noted in performance related to Listening
Comprehension, a more heavily attentionally
loaded task (t = 852, df = 121, p < .000001).
DISCUSSION

All sensory perception is based on the
effectiveness of the arousal level of
nonspecific, mostly subconscious, activity
of the brain. No specific sensory modality

perception like vision or hearing can exist
without a baseline arousal level. The more
stimulation or greater frequency of
stimulation, the more aroused an individual
will be. Luria (32) postulated that the brain
was divided into three functional units: 1)
the arousal unit, 2) the sensory receptive
and integrative unit, and 3) the planning
and organizational unit. He subdivided the
last two into three hierarchic zones. The
primary zone is responsible for sorting and
recording incoming sensory information.
The secondary zone organizes and codes
information from the primary zone. The
tertiary zone is where data are merged from
multiple sources of input and collated as the
basis for organizing complex behavioral
responses (32). Luria’s dynamic progression
of lateralized function is similar to
Hughlings Jackson’s Cartesian coordinates
with respect to progressive function from

 G LEISMAN ET AL

brainstem to cortical regions (33).
Accordingly, the goal of clinical
intervention is to attempt to develop brainbased intervention strategies for children
with dysfunctions of lateralization that
would seem to be threefold: first, to isolate
cognitive abilities that are especially
important for learning and language
development, along with deficiencies in
these abilities that might distinguish
between poor and normally developing
learners; second, to isolate experiential and
instructional variables that differentially
affect achievement in school and other life
programs; and third, to isolate the genetic
and neurological underpinnings of the
cognitive abilities underlying academic
abilities in ADD/ADHD children in the
interest of distinguishing between genetic
and neuropathological causes of deficits in
these abilities in childhood.
Brain development and the adequacy of
it functioning are dependent on sensory
input. Specific sensory perceptual processes
like vision and hearing are dependent on
non-specific sensory input. This, in turn,
creates a baseline arousal and synchronization of brain activity. This is a form of
constant arousal and is dependent on a
constant flow of sensory input from
receptors that are found in muscles of the
spine and neck. These receptors receive the
majority of their stimulation from gravity,
creating a feedback loop that forms the
basis of most if not all of brain function.
Sensory input drives the brain, and motor
activity drives the sensory system. Without
sensory input the brain cannot perceive or
process input adequately. Without motor
activity provided by constant action of
postural muscles a large proportion of
sensory stimuli are lost to further
processing. This loop is the somatosensory
system (34).
Of particular interest in this study was
that the Brown Attention Deficit Disorder

279

Scale data, when completed at the outset of
the intervention by the 60 participants’
parents, revealed that all participants were
ADD/ADHD. After the course of the 12week hemispheric specific intervention,
81% were considered to no longer be
demonstrating ADD/ADHD behaviors,
based on the Brown Scale.
We here attempted a pilot study to
determine if treatment that is preferentially
aimed at a hypothesized interactive right
hemisphere in ADD/ADHD children would
have an effect on their sensory motor
performance, as well as on cognitive
function related to attention focus. The
results support further examination through
a large-scale clinical trial of the notion of
differential hemispheric training on
attentional performance in childhood as a
potential of non-drug therapeutics in the
treatment of attentional problems of
childhood. The clinical trials will have to
examine the differential effects of
medication and hemispheric specific
treatment, as well as the effects of
nutritional interventions on academic and
on sensory, motor, attentional, and signal
detection performance.
ACKNOWLEDGMENTS

This work was supported in part by the FR
Carrick Research Institute Foundation.
Authors RM, MO, and CT have financial
interests in the clinics from which the
outcome data were obtained.

REFERENCES

1.

2.

Melillo R, Leisman G. Neurobehavioral
disorders of childhood: An evolutionary
approach. New York: Kluwer, 2004.
Melillo R, Leisman G. Autistic spectrum
disorder as a functional disconnection
syndrome. Rev Neurosci 2009;20:2:
111-31.

 280

UNDERACTIVE HEMISPHERIC FUNCTION IN ADD

3.

Coleman WL. Social competence and
friendship formation in adolescents
with
attention-deficit/hyperactivity
disorder. Adolesc Med State Art Rev
2008;19(2):278-99.
4. Burt, SA. Rethinking environmental
contributions to child and adolescent
psychopathology: A meta-analysis of
shared environmental influences. Psychol
Bull 2009;135(4):608-37.
5. Breslau J, Miller E, Breslau N,
Bohnert K, Lucia V, Schweitzer J. The
impact of early behavior disturbances
on academic achievement in high
school. Pediatrics 2009;123(6):1472-6.
6. Herrmann MJ, Mader K, Schreppel T,
Jacob C, Heine M, Boreatti-Hummer
A, et al. Neural correlates of
performance monitoring in adult
patients with attention deficit hyperactivity disorder (ADHD). World J
Biol Psychiatry 2009 May 19:1-8. [E
pub ahead of print]
7. Jacob R, Chowdhury AN, Ganesan J.
Attention deficit/hyperactivity disorder
(ADHD) in adults. Indian J Med Res
2009;129(1):83-8.
8. McIntosh D, Kutcher S, Binder C,
Levitt A, Fallu A, Rosenbluth M.
Adult ADHD and comorbid depression:
A consensus-derived diagnostic algorithm for ADHD. Neuropsychiatr Dis
Treat 2009; 5:137-50.
9. Meijer WM, Faber A, van den Ban E,
Tobi H. Current issues around the
pharmacotherapy of ADHD in children
and adults. Pharm World Sci 2009;31
(5):509-16.
10. Leisman G, Melillo R. EEG
Coherence measures functional disconnectivities in autism. Acta Paediatr
2009;98:14-5.
11. Leisman G, Koch P. Networks of
conscious experience: Computational
neuroscience in an understanding of

12.

13.

14.

15.

16.

17.

18.

19.

20.

21.

life, death, and consciousness. Rev
Neurosci 2009;20(3):151-76.
Leisman G. The role of visual
processes in attention and its disorders.
In: Leisman G, ed. Basic visual processes
and learning disability. Springfield, IL:
Charles C Thomas, 1976:7-123.
Leisman G, Ashkenazi M. Aetiological factors in dyslexia: IV.
Cerebral hemi-spheres are functionally
equivalent. Int J Neurosci 1980;11:
157-64.
Leisman G, Zenhausern R. Integratory
systems deficits in developmental
dyslexia In: Malatesha RN, Hartlage L,
eds. Neuropsychology and cognition.
Amsterdam: Elsevier, 1982: 479-506.
Sroka H, Solsi P, Bornstein B. Alexia
without agraphia with complete recovery.
Functional disconnection syndrome.
Confin Neurol 1973; 35(3): 167-76.
Galaburda AM, Sherman GF, Rosen
GD, Aboitiz F, Geschwind N. Developmental dyslexia: 4 consecutive
patients with cortical anomalies. Ann
Neurol 1985;18:222-33.
Kaufman WE, Galaburda AM.
Cerebrocortical
microgenesis
in
neurologically normal subjects. A
histopathological study. Neurology
1989;39:257-69.
Duane DD. Commentary on dyslexia
and neurodevelopmental pathology. J
Learn Disabil 1989;22:219-20.
Geschwind N, Levitsky W. Left-right
asymmetries in temporal speech
region. Science 1968;161:186-7.
Orton ST. A physiological theory of
reading disability and stuttering in
children. N Engl J Med 1928;199:
1046-52.
Bryden MP. Does laterality make any
difference? Thoughts on the relation
between cerebral asymmetry and
reading. In: Molfese DL, Segalowitz
SJ, eds, Brain lateralization in

 G LEISMAN ET AL

22.
23.
24.

25.

26.

27.

children: Developmental implications.
New York: Guilford, 1988:509-25.
Corballis MC. Human laterality. New
York: Acad Press, 1983.
Lenneberg EH. Biological foundations
of language. New York: Wiley, 1967.
Satz P. The Dejerine hypothesis:
Implications for an etiological reformulation of developmental dyslexia.
In: Obrzut JE, Hynd GW, eds. Neuropsychological foundations of learning
disabilities: a handbook of issues,
methods, and practice. New York:
Acad Press, 1991:99-112.
Obrzut JE. The Geschwind-BehanGalaburda theory of cerebral lateralization: thesis, antithesis, and synthesis?
Brain Cogn 1994;26(2):267-74.
Keshner EA, Peterson BW. Motor
control strategies underlying head
stabilization and voluntary head
movements in humans and cats. Prog
Brain Res 1988;76:329-39.
Rabiner DL, Malone PS. The impact
of tutoring on early reading achievement for children with and without
attention problems. J Abnorm Child

281

Psychol 2004;32(3):273-84.
28. Iversen JA, Tunmer WE. Phonological
processing skills and the reading recovery
program. J Educ Psychol 1993;85:112.
29. Pinnell GS. Reading recovery: Helping
at-risk children learn to read. Elem Sch
J 1989;90(2):161-83.
30. Brown TE. The Brown attention
deficit disorder scale. San Antonio,
TX: Pearson, 2001.
31. Wechsler D. Wechsler individual
achievement test, second edition, San
Antonio: Pearson, 2001.
32. Luria AR. The working brain. New
York: Basic Books, 1973.
33. Kinsbourne M, Hiscock M. The normal
and deviant development of functional
lateralization of the brain. In: Mussen
P, Haith M, Campos J, eds. Handbook
of child psychology, ed 4. New York:
Wiley, 1983.
34. Leisman G, Melillo R. Cortical
asymmetry and learning efficiency: A
direction for the rehabilitation process.
In: Randall SV, ed. Learning
disabilities: New research. Hauppauge,
NY: Nova Sci, 2006:1-24.