Paper 3592

European Review for Medical and Pharmacological Sciences

2014; 18: 2145-2147

Serial EEG study in a girl with Landau-Kleffner
Syndrome associated with continuous spikes andwaves during slow sleep
G. IMATAKA, O. ARISAKA
Department of Pediatrics, Dokkyo Medical University School of Medicine, Tochigi, Japan

Abstract. Landau-Kleffner syndrome (LKS) israre epileptic encephalopathy in childhood, characterized by both acquired epileptic aphasia andabnormal epileptiform discharges in electroencephalogram (EEG). We herein report a serial
EEG study in LKS. A 22-month old girl was referred to our hospital because of frequently partial seizures in her left upper limb. On EEG performed and multiforcal spikes were recognized.
Oral treatment of carbamazepine was started but
her seizures were not controlled. Her language
ability did not progress after 2 years of her age.
At age 4 years, carbamazepine was switched tovalproic acid, leading to reduction in the frequency of seizure episodes. She was able to speak
two-word sentences at 4 years of age, but herword output gradually decreased. At 5 years ofage, addition of zonisamide further reduced thefrequency of seizure episodes, but failed toachieve complete control of seizures. She increasingly asked for questions to be repeated.
Auditory brainstem response testing performedat the department of otolaryngology revealed
normal hearing ability. She was diagnosed ashaving intellectual deficits with an intelligencequotient (IQ) of 61 at 7 years of age. The EEG at 8years of age showed continuous spikes andwaves during slow sleep (CSWS), leading to a diagnosis of LKS. After age 11 years, the CSWS on
EEG improved without requiring a change inantiepileptic drugs (AEDs). Treatment with theoral AEDs was discontinued at 13 years of herage. Her IQ at 13 years of age was in the low 70s.
Key words:
CSWS, ESES, Aphasia.

Introduction
Landau-Kleffner syndrome (LKS) is an epileptic encephalopathy, which is diagnosed based on
acquired epileptic aphasia and electroencephalogram (EEG) abnormalities1. LKS typically develops in children between 2 and 11 years of age andis a rare syndrome according for 0.2% of all childhood epilepsy cases. It is believed to manifest auditory agnosia that involves the region close toHeschl’s gyri in the temporal lobe2. EEG abnormalities invariably occur with seizure foci in thetemporal or parietal lobe in most cases and spikes
may be seen in the both the right and left side of
the brain. The EEG abnormalities tend to become
more pronounced during sleep than while awake.
Some LKS patients reportedly show continuous
spikes and waves during slow sleep (CSWS)3,4.
Herein, we report on a girl who was diagnosed ashaving LKS with partial seizures as an initialsymptom occurring at 1 year of age and her clinical course with the results of serial EEG studies
conducted from an early age.

Case report
The patient was a 22 month old girl with unremarkable family history and no abnormalities inmotor development. She was able to speak meaningful words at 16 months of age. She wasbrought to the hospital for management of partial
seizures. The seizures were clonic in the left arm
and leg, and showed various patterns with transient loss of consciousness and blinking. The
seizure episodes occurred several times per day.
The sleep-induced EEG record at 2 years of age
showed single spike waves in the left frontal andright parietal regions. Treatment with oral carbamazepine (CBZ) was started and the frequencyof the seizure episodes was reduced to several
times per week. She was able to speak only 5words at 3 years of age and was suspected tohave autism on health screening. Her eye contact
was normal and she was diagnosed as having language delay, rather than autism. Treatment withCBZ was discontinued at approximately 4 yearsof age, with a switch to valproic acid (VPA). The
frequency of the seizure episodes diminished toCorresponding Author: George Imataka, MD; geo@dokkyomed.ac.jp2145

G. Imataka, O. Arisaka

Figure 1. A, Sleep-induced EEG recording (4y11m): Multifocal single spikes are recorded in the left frontal, left central,right parietal, right occipital and left postero-temporal regions, etc. B, Sleep-induced EEG recording (8y2m): Continuous
spikes and waves during slow sleep (CSWS) appeared in at least 85% of the EEG recordings obtained during sleep. C, Sleepinduced EEG recording (13y10m): There are no epileptic abnormalities.

several times per month. However, grand mal
seizures with falling after transient loss of consciousness occurred. She was temporarily able tospeak two-word sentences, but her word output
gradually decreased after age 4 and a half. The
sleep-induced EEG record showed multifocal
spikes (Fig.1A). Based on her clinical course, she
was diagnosed as having acquired aphasia andintellectual deficits associated with epilepsy andEEG abnormalities, i.e., LKS. Addition of zonisamide to her treatment regimen at 5 years ofage further reduced the frequency of seizure
episodes, but failed to achieve complete control.
After approximately age 5 and a half year, shebegan asking her mother to repeat questions withgrowing frequency. Auditory brainstem response
testing performed revealed normal hearing ability. Although she entered a regular elementary
school class at 6 years of age, she was transferredto special needs school because of poor learning
performance. She was diagnosed as having intellectual deficits with an intelligence quotient (IQ)
of 61 at 7 years and 7 months of age. Thereafter,
the frequency of her speech as well as conversation diminished. The sleep-induced EEG record
at 8 years of age revealed CSWS (Fig. 1B). She
experienced menarche at 11 years of age. After
12 years of age, her seizure episodes resolved. At
13 years of age, she stopped taking antiepileptic
drugs (AEDs). The sleep-induced EEG record
showed no epileptic abnormalities (Fig.1C). Her
IQ at 13 years of age was in the low 70s.
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Discussion
LKS patients first develop auditory language
disorders followed by expressive language disorders; patients with severe LKS may develop
global aphasia and intellectual deficits2. The present patient had simple partial seizures as an initial symptom of LKS at age 1 year, earlier thantypical onset age. The main symptom of LKS is
acquired aphasia1. No seizure episodes occur in
30% of LKS patients5. Acquired aphasia may
easily be recognized when LKS without seizuresdevelops in school-aged children who have already achieved some degree of language development. However, as in our present patient, it isdifficult to detect epilepsy-associated language
disorders in infants under 2 years of age who develop LKS without seizures. Thus, the findingsof early onset LKS are often presumed to be attributable to a hearing disorder. LKS is often
mistaken for autism because 30% of autistic cases are also complicated by epilepsy4. Based onthese factors, it is important for children withlanguage disorders or who are suspected to haveautism to undergo examinations allowing LKS or
comorbid epilepsy to be diagnosed by EEG.
However, EEG findings in LKS may vary withage. Early in the course of this disease, the EEG
patterns are similar to those recorded in localization-related epilepsy or benign childhood epilepsy with centro-temporal spikes6. Some studies
have shown that CSWS appears with language

Serial EEG study in a girl with Landau-Kleffner Syndrome

disorder worsening3. In the present case, simple
partial seizures initially occurred and CBZ wasprescribed. However, CBZ is ineffective for thetreatment of LKS and the use of this AED should
be carefully considered in early-onset LKS inwhich identifying language disorders is difficult7.
Concerning outcomes of LKS, most patients reportedly have residual language deficits and experience spontaneous resolution of seizure
episodes after the school-age period. Interestingly, the EEG findings in the present case changed
from multifocal spikes to CSWS and then improved.
Achieving language disorder improvement is amajor target of treatment strategies for LKS. InLKS, an early-age onset and a longer duration ofCSWS are believed to be associated with serious
language deficits. Several studies have found thattreatment with adrenocorticotropic hormone, immunoglobulin is effective based on LKS being aform of encephalopathy3,8. In the field of neurosurgery, the multiple subpial transection procedure is reportedly effective for ameliorating language disorders5. These treatments were not usedin the present patient. Her seizure outcome wasfavorable, but intellectual deficits and the language disorder persisted. Patients who haveautistic symptoms or language disorders should
undergo serial EEG testing, even if they have noseizures. If CSWS is found, LKS should be considered in the differential diagnosis, and the implementation of early immunologic therapy orsurgery for epilepsy should be considered.
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Conflict of interest

The Authors declare that they have no conflict of interests.

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