Acta Oto-Laryngologica

ISSN: 0001-6489 (Print) 1651-2251 (Online) Journal homepage: http://www.tandfonline.com/loi/ioto20

Dominant Functions of Right versus the Left
Hemisphere
M. Mostafa, M. N. Kotby, M. Barakah, S. El-Sady, T. Allosh, A. Elshobary & M.
Saleh
To cite this article: M. Mostafa, M. N. Kotby, M. Barakah, S. El-Sady, T. Allosh, A. Elshobary & M.
Saleh (1989) Dominant Functions of Right versus the Left Hemisphere, Acta Oto-Laryngologica,
107:5-6, 479-484, DOI: 10.3109/00016488909127544
To link to this article: http://dx.doi.org/10.3109/00016488909127544

Published online: 08 Jul 2009.

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Acta Otolaryngol (Stockh) 1989; 107: 479-484

Dominant Functions of Right versus the Left Hemisphere
M. MOSTAFA,’ M. N. KOTBY,’ M. BARAKAH,’ S. EL-SADY:
T. ALLOSH,’ A. ELSHOBARY’ and M. SALEH’
From the ‘Department of Neurology, and the 2Department of Otolaryngology, Unit of Phoniatrics,
Faculty of Medicine, Ain Shams University, Cairo, Egypt

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Mostafa M, Kotby MN, Barakah M, El-Sady S, Allosh T, Elshobary A, Saleh M.
Dominant functions of right versus the left hemisphere. Acta Otolaryngol (Stockh) 1989;
107: 479-484.
The aim of this work was to study the function of the left and right cerebral hemispheres
concerning linguistic, musical and cognitive abilities, through the evaluation of the deterioration of these domains following lesions of either hemisphere. The study was canied out
on 80 subjects (60 d,20 9 ) with a mean age of 48 years. Subjects were categorized into
four groups, 20 in each. Group I had left brain lesion with dysphasia; group 11, left brain
lesion without dysphasia; group 111, right brain lesion without dysphasia; group IV,
control. Patient’s evaluation included a dysphasia test, psychometric battery, tests for
musical abilities, brain CT scanning and EEG. Group I showed deterioration in the
linguistic abilities, while groups I1 and 111 had intact abilities. Deterioration in musical
abilities was noticed in group 111, with normal scores in groups I and 11. There was
deterioration of the intellectual abilities in all patients’ groups, to varying degrees. The
significance of the results is discussed. Key words: cerebral organization of language,
music in the brain, dysphasia.
M. Nasser Kotby, 11 El-Ansary street, Manshiet El-Bakry, Cairo, Egypt.

In many respects cerebral specialized dominance constitutes a model problem in neurosciences (1). The study of functional deficits in unilateral cerebral lesions remains one of the
means for investigating the organization of function in each hemisphere.
The aim of this work was to study the deficits resulting from either left or right brain
lesions, utilizing a special battery of investigations in order to get a better understanding of
the functions of each hemisphere, thus permitting a better insight into the diagnostic,
therapeutic and prognostic problems of dysphasic patients.
MATERIAL AND METHODS
Sixty right-handed patients with cerebrovascular accidents were studied. They were
classified into three groups each of 20 subjects:
Group I: 16 d,4 9 ) with left cerebral lesions causing dysphasia (ages ranging 20-65 years;
mean age, 43.5 years).
Group 11: (17 6,
3 9 ) with left cerebral lesions not causing dysphasia (ages ranging 25-73
years; mean age, 51.4 years).
Group 111: (15 cf, 5 9 ) with right cerebral lesions not causing dysphasia (ages ranging
20-70 years; mean age, 47.4 years).
A fourth group (group IV) (12 d,8 9 ) of normal subjects (ages ranging 20-70 years) was
used as a control group. Mean age, 35.1 years.
Each subject went through a detailed schedule of data collection including: Patient
interview and clinical examination, language test (2), musical test for simple rhythm
discrimination and melody perception (3), a battery for non-verbal psychometric evaluation of cognitive and perceptual aptitudes (4, 5 , 6 , 7 ) , and computerized tomography (CT)

Acta Otolaryngol (Stockh) 107

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480 M . Mostafa et al.

Fig. 1 . CT without contrast, showing left extensive temporoparietal infarction. Male; 50 years. Language: predominantly expressive dysphasia. Musical abilities: slightly affected. Cognitive abilities: affected; below average.
Fig. 2. CT without contrast, showing left superficial parietal infarction. Female; 45 years. Language: predominantly
expressive dysphasia. Musical abilities: slightly affected. Cognitive abilities: affected, mild degree.

Fig.3 . CT without contrast, showing left small penventricular infarction. Female; 41 years. Language: not affected.
Musical abilities: slightly affected. Cognitive abilities: affected, severe degree.

Fig.4. CT without contrast showing right diencephalic hematoma. Male; 38 years. Language: not affected. Musical
abilities: severely affected. Cognitive abilities: not affected; average.

Functions of right us. lefr hemisphere

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Acta Otolaryngol (Stockh) 107

Fig. 5. CT without contrast, showing
right extensive temporoparietal infarction. Male; 51 years. Language: not affected. Musical abilities: severely affected. Congnitive abilities: affected,
mild degree.

(CGR CE lOO00) of the brain. While the whole study was designed to compare the effect
of left and right hemispherical lesions, the comparison of groups I and I1 is designed
mainly to correlate left brain lesions to language deficits.
RESULTS
Associated Motoric Deficit
Right-sided hemiplegia was found in 17 cases (85%) in group I and 18 cases (90%) in group
11. Left-sided hemiplegia was found in all cases of group 111.
Language Evaluation
Affection of language function was restricted to group I only, while groups I1 and I11 had
no significant language deficits, compared with the normal controls. There was a signifi-

Table I. Language function in different groups (% of scores)
Group I
Item

Mean
score

SD

Expression
Impression
Reading
Writing
Calculation

36
61
36
35
52

33.11
22.13
37.36
13.17
39.47

SD = Standard deviation.
301-898403

Group 111

Group IV
(control)

SD

Mean
score

SD

Mean
score

0
6.04
0
4.52
6.46

100
95
100
96
95

0
5.69
0
3.43
3.98

Group I1
Mean
score
100

93
100

98
90

100

97
100
100
100

SD
0
4.78
0
0

0

481

482 M. Mostafa et al.

Acta Otolarvngol (Stockh) 107

cant difference in the results between groups I and 11, I and I11 (Table I). The differential
affection of language domains in group I showed a ‘predominantly expressive’ impairment
in 9 cases (45%), ‘predominantly impressive’ impairment in 2 cases (10%) and 9 cases
(45 %) have mixed expressive-impressive impairment.

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Seashore Test for Musical Talents
There are significant differences between groups I and IV regarding loudness, rhythm and
time, between groups I1 and IV in rhythm only, and between groups I11 and IV in all the 6
subtests except timbre. Timbre and tonal memory showed the lowest relative scores in all
groups. Group I11 showed a special tendency to a stability of the low score figures in all
members of this group. In the other groups there were, on the other hand, great intragroup
variations (Table 11).
Psychometric Aptitudes

There was a significant difference in the results of psychometry between all patient groups
and the control group. The patient groups (I, 11, 111) fell within the range of mild cognitive
and intellectual impairment. There was no significant difference in the results between the
patient’s groups. Intragroup variations of the results were minimal (Table 111).

Table 11. Seashore test scores
Group I1

Group I

Group 111

Group IV
Mean
score

SD

16.3
19.1
33.9
27.5
6.5
8.9

20.42
19.23
29.76
27.79
11.36
16.42

Item

Mean
score

SD

Mean
score

SD

Mean
score

Pitch
Loudness
Rhythm
Time
Timbre
Tonal memory

13.5
4.8
4.3
11.7
6.1
2.1

14.85
7.40*
7.14*
20.76*
13.03
2.98

12.8
12.5
16.1
18.4
6.7
6.5

20.27
21.67
17.32*
26.38
6.94
9.23

4.4
4.9
2.3
1.9
1.65
1.10

SD
4.70*
10.59*
4.05*

0.93*
1.38
0.44*

SD = Standard deviation. * Significant difference, p < 0 . 0 5 . Patient groups were compared with
control group, using Student’s t-test.

Table 111. Psychometric evaluation scores
Group I
Item
Snijder-Ooman
Progressive matrices of Raven
Bender-Gestalt
MamanneFrostig

Mean
score

Group I1
SD

Mean
score

SD

Group 111

Group IV

Mean
score

Mean
score

SD

SD

55.4
17.5*
Mild degree
of M.R.
Organic

66.5
22.13*
Mild degree
of M.R.
Organic

57.0
16.54*
Mild degree
of M.R.
Organic

103.5
20.18
Average
intelligence
Normal

60.8

73.8

68.4

94.9

19.79*

19.97*

14.39*

9.34

SD = Standard Deviation. M.R. = Mental retardation. * Significant difference, p<0.05. Patient
groups were compared with control group, using Student’s t-test.

Functions of right us. lefi hemisphere

Acta Otolaryngol (Stockh) 107

Results of Computerized Tomography (CT)
I. Type of lesion
Cerebral infarction was found in 18 cases in group I (90%), 13 cases (65 %) in group I1 and
12 cases (60%) in group 111. A hematoma was encountered in one case in group I (5 %) and
in another case in group 111 (5%). No pathological CT findings were found in one case
(5%) in group I, 7 cases (35%) in group I1 and 7 cases (35%) in group 111.

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11. Site of the lesion

Superficial lesions are encountered with more than deep lesions in all groups (Table IV).
Language is affected more frequently in superficial than in deep lesions. Impressive
language is more affected in temporoparietal lesions, but expressive language is equally
affected in both parietal and temporoparietal lesions. Left brain lesions, not causing
dysphasia do not involve the temporal lobe. Cognitive abilities are affected more with
superficial lesions but no correlation was found between the cognitive abilities and the
exctent of the lesion. No consistent relation was found between the site and extent of the
lesion and the specific deficit in musical abilities.

DISCUSSION
Brain lesions result in a wide spectrum affection of patients’ aptitudes, irrespective of the
hemisphere affected. Language functions are affected more significantly in left hemisphere
lesions. Expressive deficits are generally more frequent than impressive deficits. Normal
language aptitudes in group I1 may be explained by the fact that the brain lesions may have
been either deep-seated hemispherical, or brain stem lesions not affecting language and not
shown in CT (35%). The rest (65%) have either small periventricular, small parietal, or
occipital lesions. Lesions causing dysphasia on the other hand are significantly more
superficial and more extensive than lesions not causing dysphasia. The presence of
cognitive affection even in cases not showing any lesions in the CT in groups I1 and 111
may indicate that small, deep-seated lesions can cause a cognitive defect, such lesions
when big enough may explain the pathogenesis of ‘subcortical dementia’. Musical abilities
are affected more significantly in right hemisphere lesions with a more consistent and
wider range of affection, indicating that the right hemisphere may play a specific role in
musical perception.

Table IV. CTfindings (site of the lesion)
Site of the lesion

Group I

Group I1

Group I11

Superficial (cortical)
1. Frontoparietal
2. Parietal
3. Ternporoparietal
4. Occipital

13 (65%)
3 (15%)
-

1 (5%)
6 (30%)

-

1 (5%)
5 (25%)
3 (15%)

I (5%)

-

4 (20%)

1 (5%)

Deep
1. Periventricular
2. Diencephalic
(basal ganglia)

-

1 (5%)

3 (15%)

Free

I (5%)

7 (35%)

7 (35 %)

3 (15%)

483

484 M . Mostafa et al.

Acta Otolaryngol (Stockh) 107

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Krauthame G, eds. Lateralization in the nervous system. New York: Academic Press, 1977.
2. Kotby MN, Moustafa M, El Banouby MH, Barakah M. A modified scoring system for testing
language disability in dysphasic patients. HNO Praxis (Leipzig) 1981; 6: 194-8.
3. Seashore L, Lewis D, Saetveit JG. Revision of the seashore measures of musical talents. The
Psychological Corporation, 304 East 45th Street, New York: 1960.
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Groningen: Walters Noordhoft NV, 1970.
5 . Raven JC. Guide to using the coloured progressive matrices. London: AK Lewis, 1960.
6. Frostig M, Lefever W, Whittlesey G. Administration and scoring manual for development test of
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