MEG and EEG in LandauKleffner Syndrome

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MEG and EEG in Landau-Kleffner Syndrome

• Ritva Paetau, M.D.
• Department of Child Neurology and BioMag
  Laboratory, University of Helsinki, and Brain
  Research Unit, Helsinki University of Technology

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Functional anatomy of Sylvian regions
foot foot
Frontal eye field
hand hand
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Functional anatomy of Sylvian regions
foot foot
Frontal eye field
hand hand
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Functional anatomy, bilateral
MEG-sources Sensory II Oral Motor I Auditory
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In the Sylvian region ONE normal hemisphere
alone ensures normal functiongt something is
wrong in BOTH hemispheres if LKS

• 1. Bilateral structural lesions?
• 2. Bilateral epileptic activity?

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Bilateral synchronous spike-waves gtEpileptic
Encephalopathy

• 2-13-year old children deteriorate with
  continuous spike-waves during non-REM sleep
• Fluctuating oral motor symptoms
• Auditory agnosia, severe receptive aphasia
• Autistic spectrum disorder
• May result in permanent disability
• CAN SURGERY HELP?

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Bilateral synchronous spike-waves gtEpileptic
Encephalopathy

• YES, IF
• There is only one pacemaker for all bilateral
  synchronous spike-wave activity
• no realistic prospect of spontaneous or
  drug-induced recovery (within 2 years)
• gt SURGERY EVALUATION

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Magnetoencephalography (MEG) EEG is part of
surgery workup
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MEG reflects fissural cortex activity, EEG is
dominated by gyral crown activity
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Vectorview (Neuromag 306)
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Continuous MEG and EEG Spikes in Thiopental Sleep
MEG Right temp MEG Left temp EEG Right
centr EEG Left centr L ear R ear
Page 10 s EEG reference nose Ritva Paetau
2005
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MEG reflects fissural cortex activity, EEG is
dominated by gyral crown activity
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Are Bilateral spike-wave generators1. truly
multifocal independentor2. dependent on a
primary focal pacemaker?
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EEG and MEG record different neuron populations
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Source analysis of MEG signals
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MEG

• DEPENDENT SPIKES
• CONSTANT LATENCY
• ? SURGERY

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Apparent EEG-MEG disagreement

• Methohexital test scalp EEG gtLeft onset
• Sleep MEG gt Right intrasylvian onset
• WADA test gt Right hemisphere onset
• Right intrasylvian surgery (MST)gt language
  recovery, no epilepsy (F-up 4 years)

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• INDEPENDENT MULTIFOCAL SPIKES
• ? NO SURGERY

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Functional anatomy, bilateral
MEG-sources EEG-sources Sensory II Oral Motor
I Auditory
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Sources of MEG spikes in LKS (Paetau)

• Bilateral. Independent 59
• Bilateral., 1 trigger 17
• Multifocal 24
• Auditory cortex 33

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LKS Sources of MEG-spikes(Lewine 2000)

• Classical LKS N6
• Sylvian unilateral 2/6 (33)
• Sylvian bilateral, dependent 3/6 (50)
• Sylvian, bilateral inderpendent 1/6 (17)
• Variant LKS N9
• Sylvian frontal spikes 9/9 (100)
• Autistic Epileptic Regression N100
• Sylvian multifocal 70/100

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Both MEG and EEG needed

• MEG alone may fail strictly radial spikes
• EEG alone may fail tangential (fissural) spikes
• TIMING of MEG vs EEG and of
• left vs right spikes is CRUCIAL
• Bilateral Sylvian spikes with developmental
  arrest / regression indicate MEG-EEG-based source
  analysis to evaluate the possibilities for
  surgical treatment

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Thank you for your attention
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LKS classification (Morrell-95/Lewine-00)

• Classical Landau-Kleffner syndrome
• Regression in language comprehension
• Continuous Spike-Waves in Sleep (CSWS)
• Variant Landau-Kleffner Syndrome
• Language regression
• Epileptic EEG (spikes, no CSWS)
• No important autistic features
• Autistinen Epileptic Regression (DSM IV)
• Early regression (lt2y) of language and social
  skillsepileptic EEG

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Outcome after surgery in Landau-Kleffner sdr

• Morrell 1995
• MST (multiple subpial transsection) of the
  spiking cortex
• Language development (N12)
• Normal language 6
• Better 5
• No change 1

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LKS Surgery outcome (Lewine 2000)

• Classical LKS N6
• Good outcome 5/6
• Transiently better 1/6
• Variant LKS N9
• Significantly Better 6/9
• Autistic Epileptic Regression N30
• Significantly Better 7/30
• Slightly Better 15/30
• No change 8/30

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Magnetic auditory evoked responses

• Right Left
• LKS
• 6y
• Normal
• 10 y