292

Interhemispheric Reorganization of Motor Hand
Function to the Primary Motor Cortex Predicted
With Functional Magnetic Resonance Imaging and
Transcranial Magnetic Stimulation

ondary sensorimotor areas in the lesional and, to a lesser extent,
contralesional hemisphere, as well as in areas not directly involved

in motor control (parietal and prefrontal cortices). ’~-11 Occasionally,

additional activation of the contralesional primary motor cortex has
been reported.12-16 However, it remains largely unknown to what
extent these techniques can accurately predict postoperative motor

ABSTRACT

function as only a few studies have been performed prior to introThe objective of this study was presurgical assessment of reorga-

nization of motor hand function in an 11-year-old girl with intractable
epilepsy and a right-sided hemiplegia resulting from an extensive

perinatal left hemispheric stroke. Prior to a left functional hemispherectomy, functional magnetic resonance imaging (MRI) showed
that both nonparetic and paretic motor hand function predominantly
activated the right primary motor cortex, whereas no activation was
found in the left hemisphere. Transcranial magnetic stimulation of
the right central area yielded responses in both the nonparetic and
the paretic hand, whereas no responses were obtained after stimulation of the affected hemisphere. Both techniques indicated that
motor function was mediated by corticospinal fibers originating
from the undamaged (primary) motor cortex and predicted no
further loss of motor hand function after surgery. Indeed, subsequent functional hemispherectomy induced no new sensorimotor
deficits. Functional MRI was repeated 22 months after surgery
and matched preoperative sensorimotor functional MRI findings,
confirming reorganization of the primary motor cortex. No additional reorganization was introduced by surgery. (J Child Neurol
2002;17:292-297).

duction of a (surgical) lesion. 14,16,17 Moreover, brain activity maps rely
heavily on data analysis procedures and statistical methodology.
In patients who are candidates for functional hemispherec-

tomy, the amobarbital (Wada) test is regarded as the gold standard
for the prediction of postoperative motor function following hemispherectomy. There is, however, a need for less invasive alternatives as several potential risks and disadvantages limit use of the
Wada test for this purpose (eg, it only allows for lateralization of

function). Two promising noninvasive techniques to predict postoperative motor hand function prior to a functional hemispherectomy are functional MRI and transcranial magnetic stimulation.
Transcranial magnetic stimulation directly stimulates cortical areas
and is thought to identify only those areas that are directly linked
to descending corticospinal projections.18 Recent studies have
suggested that transcranial magnetic stimulation can be used complementary to functional MRI in the preoperative assessment of
motor function as it may aid in the differentiation between criti-

cal and noncritical motor areas detected with functional MRL’~3~1s~’‘’
In the current study, we applied both techniques, as well as the Wada

test, to determine which brain areas mediated motor function in

patient with severe unilateral brain damage. To assess whether
surgical resection altered the representation of sensorimotor hand
function, functional MRI was repeated 2 years after surgery.
a

Patients who are candidates for neurosurgical resection of epilep-

togenic brain areas meet strict preoperative criteria to ensure that
surgery reduces or abolishes epileptic seizures while sensorimotor
and cognitive functions remain unaffected. In some of these patients,
cerebral functions have reorganized as a consequence of the epileptogenic lesion (ie, have shifted from their normal cortical localization to other brain areas).’ Identification of these patterns of

reorganization, and subsequent prediction of functional impact of
the planned resection, would be of great clinical benefit.
Motor recovery that follows extensive unilateral brain injury
in early life can be impressive, often allowing children to reach and
grasp with their affected hand and walk with only a mild hemiparetic
limp. In patients who have undergone a cerebral hemispherectomy, sensorimotor functions can be served by only a single hemisphere.2 However, mechanisms and constraints of reorganization
are largely unknown. Individual patterns of intra- and/or interhemispheric reorganization depend on at least several variables such
as age, lesion size, and topography and integrity of surrounding brain
areas.1-4 Vining et al documented that of 58 hemispherectomies performed in children, motor function worsened in 17%, improved in
33%, and remained unchanged in 50%.1
Both functional magnetic resonance imaging (MRI) and
positron emission tomography (PET) provide detailed individual
brain activity maps by measuring local cerebral blood flow patterns
induced by changes in neural activity.5 Several studies have investigated postlesional organization of motor functions using functional
MRI or PET. Most studies found pronounced activation of sec-

Case Report

’

An 11-year-old girl underwent a left functional hemispherectomy, aiming at
the relief of medically intractable seizures. Gestation had been uncompli-

cated, and there were no adverse perinatal events. Shortly after birth, a spastic right-sided hemiparesis was noted. A computed tomographic scan at the
age of 5 months showed a large cyst in the left hemisphere, suggesting a
perinatal stroke. Complex partial epileptic seizures started at the age of
9 months. Since that time, the patient has never been free of seizures,
despite various antiepileptic medication. Psychomotor development was
retarded: walking at 2 years and talking at 4 years. In the years before
surgery, her IQ declined from 70 to 45 (Wechsler Intelligence Scale for
Children-Revised [WISC-R]), presumably owing to an increase in seizure frequency. At the time of presurgical evaluation, the patient showed strong involuntary movements of the nonparetic hand (with intentional movements of
the paretic hand) and mild mirror movements of the paretic hand (with intentional movements of the nonparetic hand). Motor strength testing (Medical
Research Council scale) yielded a grade 3 strength for the proximal and distal muscles of the right arm. For the right leg, there was a grade 4 proximal
and grade 1 to 3 distal strength. Left-sided motor strength was normal
(Medical Research Council grade 5). No sensory deficits were found.
Despite her right hemiparesis, the patient could walk and ride a bicycle
unaided. Preoperative MRI indicated severe left hemispheric abnormalities:
a large porencephalic cyst, severe atrophy of the caudate nucleus and
thalamus, and cortical atrophy (Figure 1).
’

Wada Testt
Wada testing involved injection of 125 mg of amobarbital in the left internal carotid artery to assess the functional status of the right hemisphere (ie,
memory, language, and motor function). A slight reduction in right hand
motor strength was observed following injection of amobarbital. Muscle tone
was

unchanged, and the patient kept voluntary control over both arms and

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293

Figure 1.

Preoperative magnetic resonance image demonstrating a cyst in the smaller left hemisphere, severe atrophy of the left caudate nucleus

and thalamus, and left cortical atrophy.

legs. This suggested that at least part of the critical motor areas that controlled the paretic extremities was located in the ipsilateral healthy right
hemisphere. Neuropsychologic testing yielded adequate short-term memory function and revealed no dysphasia, indicating that critical language functions resided in the right hemisphere.

stimulation of the nonparetic left hand yielded a large area of activation in
the right primary sensory and motor cortex and a smaller area of activation

Preoperative Functional Magnetic Resonance Imaging

vation in the right superior parietal lobule emerged for this task.

in the left and right premotor cortex, right supplementary motor area, right
superior parietal lobe, and right secondary somatosensory cortex. Sensory
stimulation of the paretic right hand yielded no active brain areas in either

hemisphere; when statistical threshold was lowered to Tcnlll’aI 4.0, only acti=

One month prior to surgery, functional MRI’ was performed using a threedimensional BOLD technique (navigated PRESTO sequence, TE/TR 30/24.5
ms, flip angle 10 degrees, matrix 52*64*22, FOV 183*225*77 mm, voxel size
3.51 mm isotropic, scan time 7.25 s), implemented on a Philips ACS-NT 1.5Tesla scanner (Philips Medical Systems, Best, The Netherlands) with P1000
gradients.2o,21 Following functional MRI scans, an anatomic image was
acquired (three-dimensional-FFE, TE/TR 4.6/30 ms, flip angle 30 degrees,
FOV 256*256*130, voxel size 1 x 1 x 1.2 mm). Functional scans were
aligned roughly perpendicular to the course of the central sulcus and
included the frontal and parietal lobes.

Four tasks were used in the scanner-movement of the right and left
hand and tactile stimulation of the right and left hand-and were practiced
extensively beforehand. Eighty-four functional MRI scans were acquired per

task, during which periods of activity (ie, movements or tactile stimulation)
were alternated with rest periods (22 seconds’ duration each). In the scanner room, one of the authors (G.-J.M.R.) instructed the patient before each
block and monitored patient performance. During the motor task, a green
or red dot was projected on a screen that the patient could see via a mirror that was mounted on the headcoil. The active condition consisted of

squeezing a sponge in pace with the flashing green dot (1 Hz). The red nonflashing dot indicated the rest condition. For tactile stimulation, light brushing of the palm of the hand was used (paced at 1 Hz).
Prior to statistical analysis, coregistration of functional and anatomic
scans was performed.21 No functional scans were excluded from analysis. Statistical maps for each task were obtained using multiple regression analysis,
which included detrending, resulting in a value for each voxel.22 No smoothing of functional scans was applied. Statistical maps were stringently thresholded (T(’nhC’al 4.5, corresponding to P < .05 after Bonferroni correction for
the number of comparisons, ie, the number of voxels in the scanned volume)
to minimize the occurrence of false-positive brain activation.
Patient performance was excellent during both motor and sensory tasks,
and no epileptic seizures were observed. Functional MRI results for the motor
and sensory tasks are depicted in Figure 2. The central sulcus was localized
according to the method described by Yousry et al.z3 Movement of the nonparetic left hand activated the right primary motor cortex and premotor cortex. Movement of the paretic right hand activated the ipsilateral (ie, right)
primary motor cortex, close to the central sulcus, but no activation was
detected in contralateral motor areas in the affected hemisphere. Sensory
=

Postoperative Functional Magnetic Resonance Imaging
Twenty-two months after hemispherectomy, functional MRI was again performed. Procedures and experimental design (including tasks and timing)
were identical to those in the preoperative functional MRI experiment.
Owing to an upgrade of MRI hardware (P6000 gradients), three times as many
volume scans were acquired in the same amount of time (ie, 252 instead of
84 volume scans per task), whereas the number of slices increased from 22
to 26. Functional scan volume and orientation of slices were adjusted to
match settings in the preoperative functional MRI experiment.
Both movement of the nonparetic (left) hand and the paretic (right)
hand yielded activation in the same convolutions as in the preoperative functional MRI experiment (compare Figures 2A and 3A). The results from the
sensory hand tasks also closely matched preoperative functional MRI findings (compare Figures 2B and 3B).
Transcranial Magnetic Stimulation
Focal transcranial magnetic stimulation was carried out with a &dquo;figure-of-

eight&dquo; coil (diameter 70 mm per coil, peak magnetic field strength 2.2 Tesla)
and a magnetic stimulator generating a monophasic pulse (Magstim Company, Whitland, UK). The center between the coils was held at the desired
scalp position.z4 At least four stimuli were given at each of the scalp positions, Fl, F2, C3, and C4, of the International 10-20 system. Motor evoked
potentials were recorded simultaneously from the left and right abductor
pollicis brevis muscles using 1.0-cm diameter Ag/AgCI surface electrodes
in a belly-tendon montage connected to an electromyograph (Viking IV, Nicolet, standard motor nerve conduction settings). We obtained recordings without and with facilitation (slight abduction of the thumb).
Focal transcranial magnetic stimulation of the right central region (C4)
resulted in motor evoked potentials in the left and the right abductor pollicis brevis (Figure 4). No motor evoked potentials were obtained after stimulation of the left central region (C3) or the frontal regions (F3 and F4).

Facilitation yielded motor evoked potentials with shorter latency and larger
amplitude (facilitation: left abductor pollicis brevis 17.7 ms, 1.9 mV; right
abductur pollicis brevis 18.3 ms, 0.9 mV; no facilitation: left abductor pollicis brevis 22.4 ms, 0.7 mV; right abductor pollicis brevis 21.6 ms, 0.5 mV).

Surgery and Follow-up

*BOLD blood oxygen level dependent; PRESTO principle of echo shifting with a train of observations; TE echo time; TR repetition time;

The patient underwent a left functional hemispherectomy. Postoperatively,
there was a slight increase in the right-hand paresis that recovered within

FFE = fast field echo.

a few weeks to the level of

=

=

=

=

preoperative findings. Sensory functions remained

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294

Figure 2. Preoperative functional magnetic resonance images demonstrating cortical activation elicited by motor (A) and sensory (B) hand
tasks. Statistical maps (P< .05, Bonferroni corrected) are superimposed on preoperative anatomic images. Axial slices are shown in radiologic
orientation (ie, the right hemisphere is depicted on the left side and vice versa). The arrow indicates the location of the central sulcus. A, Movements of both the nonparetic left hand (green voxels) and the paretic right hand (orange voxels) activated the right primary motor cortex. In
addition, nonparetic hand movements activated the right premotor cortex. B, Tactile stimulation of the nonparetic hand (green voxels) yielded
activation in the right primary sensory and motor cortex, premotor cortex, supplementary motor area, and superior parietal lobule. Stimulation of the paretic hand yielded no activation; lowering of the threshold to Tcntica’ 4.0 yielded activation only in the right superior parietal lobule (not shown).
=

unaffected. The extent and intensity of the mirror movements remained

unchanged. Two years after surgery, the patient is still free of seizures and
has dramatically improved in social functioning. She has experienced no
worsening of language deficits. Her IQ has increased from 45 to 59.
Discussion

In this study, presurgical functional MRI and transcranial magnetic stimulation correctly predicted functional outcome of hand
motor function after a left functional hemispherectomy in an 11-

year-old patient. We were able to demonstrate that interhemispheric reorganization of right-hand motor function (to the right,
ie, ipsilateral, primary motor cortex) was not the result of the sur-

gical intervention but was present before surgery, most likely
resulting from the severe perinatal left hemispheric lesion and
medically intractable epilepsy.
Lesion studies and intraoperative electrocortical stimulation
mapping have typically located critical hand motor function within
the contralateral &dquo;hand knob,&dquo; the posteriorly curved part of the
middle genu of the precentral gyrus that can reliably be identified
via anatomic landmarks.23,25 In functional imaging studies of normal volunteers, ipsilateral activation is usually not found with a simple motor hand task (such as the one used in our study) or is
present only in addition to considerably larger contralateral acti-

Figure 3. Postoperative functional magnetic resonance images demonstrating cortical activation elicited by motor (A) and sensory (B) hand
tasks. Statistical maps (P< .05, Bonferroni corrected) are superimposed on postoperative anatomic images. Axial slices show approximately
the same anatomic volume as in Figure 1. The arrow indicates the location of the central sulcus. A Movements of both the nonparetic left hand
(green voxels) and the paretic right hand (orange voxels) activated the right primary motor cortex. In addition, nonparetic hand movements
activated the right premotor cortex. White voxels were active in both tasks. B, Tactile stimulation of the nonparetic hand yielded activation in
the right primary sensory and motor cortex, premotor cortex, supplementary motor area, and secondary somatosensory cortex (green voxels). Stimulation of the paretic hand yielded activation in the right superior parietal lobule (orange voxels).

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295

vation.26,27 Several observations supported the fact that reorganization of motor function involved the contralesional (right) primary
motor cortex and corticospinal tract: (1) both pre- and postsurgi-

cal functional MRI demonstrated a representation of paretic (right)
and nonparetic (left) hand motor function in the middle genu of
the precentral gyrus of the healthy (right) hemisphere, whereas no
activated areas were found in the damaged (left) hemisphere; (2)
transcranial magnetic stimulation indicated that these representations were directly involved in motor hand control via the cor-

ticospinal tract as stimulation resulted in symmetric short-latency
motor evoked potentials in the left and right abductor pollicis brevis muscles, whereas no motor evoked potentials were obtained
from stimulation of the central region in the left hemisphere; and
(3) left functional hemispherectomy did not affect long-term motor
hand function (there was a temporary slight decrease in motor hand
function during the first postoperative weeks). As pre- and postoperative functional MRI yielded similar brain activation maps, it
can be concluded that no (additional) reorganization of function
was induced by surgery.
A consistent finding in our study was that tactile stimulation
of the paretic hand (in which the patient did not report sensory
deficits) did not activate the ipsilateral or contralateral primary sensorimotor cortex with functional MRI, whereas stimulation of the
unaffected hand robustly activated the contralateral primary sensorimotor cortex. This agrees with the results from previous functional MRI studies in which tactile stimulation of the affected hand
in patients who had undergone hemispherectomy failed to activate

the primary sensorimotor cortex.’,8 Bittar et aT and Graveline et
al8 found that for stimulation of the affected hand, the ipsilateral

superior parietal lobule (Brodmann area 7) was a common area of
activation in these patients, consistent with our findings. This sug-

gests that a different form of reorganization has taken place for sen-

Figure 4. Preoperative findings from transcranial magnetic stimulation of the right and left central region. Stimulation of the right central region (C3) resulted in symmetric short-latency motor evoked
potentials in both the left (A) and right (B) abductor pollicis brevis muscle. Stimulation of the left central region (C4) did not result in motor
evoked potentials in the right (C) or left (D) abductor pollicis brevis
muscle.

sory hand function than for motor hand function.

Mirror movements, as observed in our patient, are the consequences of reorganization of motor function and are seen especially when brain injury occurs before 1 year of age. 21 Several

in monkeys that cortical representations of different movements

studies have demonstrated that in a subset of children with strik-

by different inputs.31
The use of a stringent statistical threshold in functional MRI
analysis resulted in correct assessment of hemispheric lateralization of motor hand function, in accordance with recent studies in
which use of a high threshold improved localization of critical
brain areas.35 However, a high threshold also lowers detection
power for brain activity. This might explain the absence of robust
activation in secondary motor areas (premotor areas and SMA),
although it is known that the &dquo;simple&dquo; motor hand task that was
used in our experiment does not consistently show activation in
these areas in normal volunteers .36 It is important to realize that
the presence of functional MRI activation in a particular brain
area does not imply that this area plays a critical role in the performance of a particular function. To distinguish critical from noncritical motor areas that were indicated with functional MRI, we
additionally used transcranial magnetic stimulation. A combination
of both techniques could become a useful and noninvasive presurgical technique to predict postoperative motor functions. 16
In children with unilateral brain injury, motor functions seem
to have a more limited potential for postnatal interhemispheric plasticity than language functions .6 This may be associated with the early

ing mirror movements and hemiplegia following early-life hemispheric damage, transcranial magnetic stimulation induces bilateral
and short-latency motor evoked potentials from the healthy hemisphere, whereas no responses are obtained from the lesioned
hemisphere .1,11,30 These studies have suggested that in these patients,
the corticospinal fibers that originate from the undamaged motor
cortex have branched and now project to motoneuron pools on both
sides of the spinal cord, leaving the healthy hemisphere in control
over both sides of the body.4,13,16,29 Such a model can account for
the mirror movements observed in our patient.4 Unmasking of
ipsilateral corticospinal axons from the healthy hemisphere is a less
likely explanation for reorganization as these fibers tend to be
relatively slow conducting and do not normally make direct corticomotoneuronal connections.4,31 The neighbouring and partly
overlapping representations of both hands in the primary motor cortex as found with functional MRI are consistent with previous
neurophysiologic studies in healthy subjects and animals. Sanes
et al showed that different finger movements are controlled by overlapping brain areas in the human primary motor cortex.32,33 Schieber
et al showed with electrical recordings of motor cortex neurons

can coexist in the same area and can be activated

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independently

296

ontogenesis of the corticospinal tract, which ends before 30 weeks’
gestation.37,:38 Most functional imaging studies of patients with
damage to the primary motor cortex have suggested a certain

10.

Muller RA, Rothermel RD, Behen ME, et al: Plasticity of motor organization in children and adults. Neuroreport 1997;8:3103-3108.

11.

Rossini PM, Caltagirone C, Castriota-Scanderbeg A, et al: Hand motor
cortical area reorganization in stroke: A study with fMRI, MEG and
TCS maps. Neuroreport 1998;9:2141-2146.
Cao Y, D’Olhaberriague L, Vikingstad EM, et al: Pilot study of functional
MRI to assess cerebral activation of motor function after poststroke
hemiparesis. Stroke 1998;29:112-122.

&dquo;resistance&dquo; of cortical motor control to shift to its homologous area
in the contralesional hemisphere. 1,8-12, 11 However, the current study,

12.

in which results obtained from functional MRI, transcranial magnetic stimulation, the Wada test, and behavioral observations con-

verged, presents strong evidence for interhemispheric reallocation
of motor hand function to the primary motor cortex and corticospinal tract. As predicted with these techniques, particularly
with functional MRI, functional hemispherectomy did not result in

13.

Nirkko AC, Rosler KM, Ozdoba C, et al: Human cortical plasticity: Functional recovery with mirror movements. Neurology 1997;48:1090-1093.

14.

Wieser HG, Henke K, Zumsteg D, et al: Activation of the left motor cortex during left leg movements after right central resection. J Neurol

15.

additional loss of sensorimotor function.
,

16.

Acknowledgments
We thank Drs van Empelen and Vermeulen and Professor van Nieuwenhuizen.

17.

Geert-Jan M. Rutten, MD

Department of Neurosurgery
Nick F. Ramsey, PhD
Department of Psychiatry
Peter C. van Rijen, MD, PhD
Department of Neurosurgery
Hessel Franssen, MD, PhD
Department of Clinical Neurophysiology
Cees W. M. van Veelen, MD, PhD
Department of Neurosurgery
University Medical Center Utrecht
Utrecht, The Netherlands

18.

19.

.

Received Oct 23, 2001. Received revised Jan 22, 2002. Accepted for publication Jan 23, 2002.

Address correspondence to Dr Geert-Jan M. Rutten, Department of
Neurosurgery, University Medical Center Utrecht, PO Box 85500, 3508 GA,
Utrecht, The Netherlands. Tel: +3130 2507977; fax: +3130 2542100; e-mail:

20.

ner. Proc Natl Acad Sci U

21.

22.

13-42.

Yousry TA, Schmid UD, Alkadhi H, et al: Localization of the motor hand
area to a knob on the precentral gyrus. A new landmark. Brain 1997;

24.

Jalinous R: Fundamental aspects of magnetic nerve stimulation, in Lissens MA (ed): Clinical Applications of Magnetic Transcranial Stimulation. Leuven, Uitgeverij Peeters, 1992, pp 11-20.

25.

Boling W, Olivier A, Bittar RG, et al: Localization of hand motor activation in Broca’s pli de passage moyen. JNeurosurg 1999;91:903-910.

26.

Rao SM, Binder JR, Bandettini PA, et al: Functional magnetic resonance
imaging of complex human movements. Neurology 1993;43:2311-2318.
Kim SG, Ashe J, Hendrich K, et al: Functional magnetic resonance imaging of motor cortex: Hemispheric asymmetry and handedness. Science
1993;261:615-617.
Woods BT, Teuber HL: Mirror movements after childhood hemiparesis. Neurology 1978;28:1152-1157.
Farmer SF, Harrison LM, Ingram DA, et al: Plasticity of central motor
pathways in children with hemiplegic cerebral palsy. Neurology 1991;

120:141-157.

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unprovoked seizures, which occurred when falling asleep or when awakening. Initial seizure symptoms were guttural sounds, drooling, and irregular respiration followed by mild rhythmic clonic movements on the left side
or bilaterally. After about 30 seconds, the cloni slowed down, and the girl
was hypotonic and unarousable. A few minutes later, she awakened and complained of a headache and colic. We investigated the case after her third
seizure. The results of pediatric and neurologic investigation were normal.
Her intelligence was above average. Blood chemistry and hematology were
normal. Her EEG was characteristic of benign rolandic or centrotemporal
epilepsy, and her cranial computed tomogram was normal. Anticonvulsive
treatment (300-mg carbamazepine daily) was introduced. During follow-up
(from September 1998 to April 2001), no further seizures were observed,
and no adverse event occurred. Cognitive performances remained excellent, and no psychologic problems emerged.

Electroencephalography
An EEG investigation was done by means of Brain Quick (Micromed,

Mestre, Italy) digital EEG equipment. Electrodes were placed according to

Ictal Electroencephalography in a Case
of Benign Centrotemporal Epilepsy

ABSTRACT
The purpose of this research was to publish a complete ictal elec-

troencephalographic (EEG) record of a child with benign centrotemporal epilepsy. The record includes a brief description of the
patient’s epilepsy syndrome, analysis of interictal and ictal EEG
records, and a description of corresponding clinical ictal events.
Ictal EEG activity appeared over the right rolandic cortex and
spread to adjacent sites. Initial rhythmic activity was followed by
bilateral series of sharply contoured slow waves. The electric field
of the seizure discharge changed during the seizure. Tangentially
oriented dipolar field was found in the middle part of the seizure.
Evolution of clinical seizure phenomena roughly corresponded to
propagation of the ictal discharge. In terms of topography and
electromorphology, this ictal record was similar but not completely identical with those reported previously. Collection of further ictal records in benign rolandic or centrotemporal epilepsy of
childhood and other epilepsy syndromes is necessary. (J Child Neu-

2002;17:297-300).
rol

Benign rolandic or centrotemporal epilepsy of childhood is a genetically determined condition with variable contribution of acquired
and pathoplastic factors.’ Its characteristics have been summarized
in excellent reviews.2-5 In most cases seizures are rare, diagnosis
and treatment are easy, and there is no need for repeated or longterm electroencephalographic (EEG) monitoring. Hence, ictal
EEGs have been recorded very rarely. Unillustrated descriptions
of ictal EEG6,7 reports of subclinical electrographic seizures8-1O or
status epilepticus’1,12 are available in the literature. Only a few
articles contain EEG records of typical clinical seizures. 1&dquo;3> 14 In this
article, we demonstrate a complete ictal EEG of a typical seizure
of a child with typical benign rolandic or centrotemporal epilepsy.
Case Report
The patient, an 8-year-old right-handed Caucasian girl, had an unremarkable
family history. Pregnancy, delivery, and developmental milestones were
normal, and she did very well at school. At the age of 8 years, she had three

the International 10-20 system, and a 19-channel EEG was recorded against

linked ears reference (both ear lobes were connected via a 20 kOhm impedance). Montage reformatting and off-line parameter resetting were possible. Standard EEG showed regular alpha background activity, and
neurometric scores of waking background activity showed no statistically
significant alterations. Sharp waves showed a dipolar potential field with
negative voltage maximum at the right midtemporal (T4) electrode and positive maximum right frontally (F4). Spontaneous sleep activated trains of
sharp and slow waves (Figure lA). In stage 2 sleep, sharp waves and sleep
patterns suddenly ceased, and 8-Hz rhythmic activity emerged in the right
midtemporal-central region (Figure 1B). A few seconds later, both EEG and
artifacts indicated arousal (Figure 1C). In the first 70 seconds of the electrographic seizure, morphology of the ictal rhythm did not change, but its
voltage increased, and its frequency slowed down to 6 Hz. Rhythmic ictal
activity gradually spread to adjacent sites (Figure 1C-E). Thereafter, rightsided rhythmic activity became irregular. At the same time, sharply contoured
high-voltage rhythmic 2-Hz activity emerged in the left hemisphere (Figure
lE-F). The final part of the seizure was characterized by bilateral rhythmic
delta activity with higher voltage on the left side and superposition of faster
rhythms on the right (Figure 1 G-H). The electrographic seizure was followed
by postictal flattening. Electroencephalographic depression was greater in
the right hemisphere than in the left (Figure 1J-I). Referential and bipolar
montages were used for phase analysis. In-phase activity was recorded
between F4, C4, and T4 electrodes at the beginning of the seizure discharge. After 20 seconds, phase reversal occurred between F4, C4 and T4,
T6 electrodes. The following electrographically irregular part of the seizure
showed no consistent phase relations. Bihemispheric in-phase delta activity characterized the terminal phase of the electrographic seizure.
Electroclinical correlation could be analyzed based on the notes of the
technician. Seizure onset and electrographic arousal were associated with
small body movements. Evolution and propagation of the seizure discharge
were coupled with drooling and mild clonic movements (laterality not
specified by the technician), whereas bilateral rhythmic delta was associated with atonia and unresponsiveness. Exact matching of clinical and
EEG data was not possible because this seizure was recorded by chance,
without video. For the same reason, no ictal and postictal testing of cerebral functions was carried out.

Discussion
In benign rolandic or centrotemporal epilepsy, motor and sensory
seizure symptoms localize seizure onset to the upper or lower

part of the precentral and/or postcentral gyrus. 15 Also, analysis of
interictal sharp waves 16 and magnetoencephalographic dis-

charges 17,18 pointed to these areas of the cortex. The coexistence
of the irritative zone and the symptomatogenic zone’9 was supported
by the observation that the first seizure symptoms and EEG interictal spikes concordantly pointed to the rostral or caudal part of

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