optimizing seizures in sleep: beyond the new guidelines seizures in sleep 2009.pdf · of known...
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Optimizing Seizures in
Sleep:
Beyond the New
Guidelines
Rebecca J. Clark-Bash, R. EEG\EP T., CNIM, F.ASNM
President, Knowledge Plus, Inc.
Lincolnshire, Illinois
815.341.0791
Why do we do EEG?
• Seizures
• Seizures
• Seizures
• Seizures
• Seizures
• Seizures
• Seizures
• Seizures
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What is A Seizure?
Seizure
A sudden, involuntary time-limited alteration in behavior,
including a change in motor activity, in autonomic
function, in consciousness or in sensation,
accompanied by an abnormal electrical discharge in the
brain
Epilepsy
A condition in which an individual is predisposed to
RECURRENT seizures secondary to a central nervous
system disorder
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What is A Epilepsy?
Epileptic Seizures
Associated with glial proliferation (scarring on the brain)
often not detected with imaging tools (provokes the
clinical event)
High percentage of patients have treatment success
with AEDs (anti-epileptic medication) or recent
advanced treatment paths such as Vagus Nerve
Stimulator, Ketogenic Diet and Surgery
Glial proliferation produces the signature of epilepsy
Non-epileptic Seizures
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What is A Epilepsy?
The signature of epilepsy:
Sharp Waves and Spikes
in the EEG.
“cat”
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What is Epilepsy?
Epileptic Seizures
Non-epileptic Seizures
Not associated with structural damage or insult
Not associated with EEG abnormalities linked to seizure
Do not respond to AED therapy
Previously called Psuedo-Seizures or “Psycho-
Seizures”
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Term Definition
Ictal EEG
Describes the recording during the event
Interictal EEG
Describes the recording in between each event
Postictal EEG
Describes the period of time immediately following an event
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EEG Abnormalities & Spikes
Similar to cardiac abnormalities in the presence of known clinical cardiac signs, the EEG has only a chance of displaying the abnormality during a clinical 20 minute test.
The statistical probability of abnormality is drastically reduced if drowsiness and light sleep are not obtained.
Activation procedures are implemented during the clinicial test to attempt to provoke the abnormality.
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Seizure Classifications
Partial Seizures
Simple Partial Seizures
Complex Partial Seizures
Generalized Seizures
Status Epilepticus
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Seizure Classifications
Classification will define the BEST medication
(AED) for treatment
An incorrect AED may not only NOT PREVENT
the seizures but also provoke them to become
more frequent and more severe.
EEG & Clinical history define and confirm the
seizure type.
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Summary of Clinical & EEG Features
of Epileptic Seizures
Seizure Usual
Duration
Loss of
Consc.
Post-Ictal
Confusion
ICTAL
EEG
Simple
Partial
5-10 sec NO NO Focal
Spikes (NL)
Complex
Partial
Variable
5-10 sec
1-2 min
YES YES Focal or
Lat. Spike
Absence 5-10 /sec
Clustering
YES NO Gen.
3 /sec S & W
Gen.
Tonic-Clonic
1-2 min YES YES Gen. High
Amp Spikes
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0
10
20
30
40
50
60
70
80
90
0-9 1O - 19 20-39 40-59 60+
EPILEPSYINCIDENCEcases peryr per100,000
Seizure Classifications
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“cat”
Seizures in Sleep: Incidence
• Sleep Epilepsies– 20-25 % have seizures exclusively or mainly at
night
• Diffuse Epilepsies– 30-40 % have seizures distributed around the
clock
• Waking Epilepsies– Remaining 35-50 % have seizures exclusively or
mainly during wakefulness
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Nocturnal Seizures
are not infrequent.
Janz, 1962; Gibberd & Bateson, 1974
Seizures in Sleep: Incidence
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Do different seizures have a tendency to start
during sleep?
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Frontal Temporal Posterior
Awake
Asleep
P<0.0001
*
*
Herman et al,
Neurology 2001;
56:1453-9.
% b
egin
ning
in s
leep
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Do some seizures generalize more often during
sleep?
0
10
20
30
40
50
60
70
80
frontal temporal occipital
Awake
Asleep
P<0.0001*
*
*
Herman et al, Neurology 2001;56:1453-9.
% g
ener
aliz
ing
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In what stage of sleep do seizures happen?
Herman et al, Neurology 2001;56:1453-9.
0
10
20
30
40
50
60
70
stage 1 stage 2 SWS REM
%seizures
%sleep
Sleep Disorders & Seizures
• Seizures may resemble in clinical profile:
– Urinary incontinence causing confusion with
enuresis nocturna
– Psychomotor automatisms of complex partial
seizures with sleep walking
– Emotional symptoms with sleep terrors or dream
anxiety attacks
– Rage epilepsy with sleep terrors or other REM
sleep disorders
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Method of Acquisition
• How many channels are necessary?
• What are the optimal filter and sensitivity settings to record abnormalities?
• What is the best paper speed (screen display) to record abnormalites?
• Should activation procedures be implemented in polysomnographic recordings when seizures are suspected?
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Ambulatory EEG:Diagnostic Yield
Bridgers &
Ebersole
(1985)
Morris
(1985)
Patients N = 206 N = 191
Seizures 11
(5.3%)
13
(6.8%)
Epileptiform
Abnormalities
25
(12.1 %)
48
(25.1%)
Total EEG
Findings
36
(17.4%)
61
(31.9%)
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Diagnostic Yield (Morris)
Total Study
PopulationNumber %
Patients in Study 344 100 %
Total Epileptiform
Abnormalities130 38.1 %
“Normal”
Pushbutton Events125 36.3 %
Total Clinical Useful
Recordings256 74.4 %
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What Technology Changed:
Number of channels:
Ebersole: 8 Channels
Morris: 16 Channels-Full Head Coverage
Filter Settings
Ebersole: Bandpass 1-35 Hz
Morris: Bandpass: 1-70 Hz
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Method of Acquisition
How many channels are necessary?
16
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Method of AcquisitionWhat are the optimal filter and sensitivity settings
to record abnormalities?
Low Filter: 1 Hz
High Filter: 70 – 100 Hz
Sensitivity: 7 µV/mm
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Method of Acquisition
What is the best paper speed (screen display) to record abnormalites?
YOUR EYES define
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Method of Acquisition
Should activation procedures be implemented in Polysomnographic recordings when seizures are suspected?
Photic Stimulation
Disco Ball
Night Driving
Rewind Video Tape or Japenese Cartoons
Hyperventilation
Developmental delay or Daydreaming
Sleep
YES!!!!!
Epileptiform Activity in Routine EEG &
Polysomnography:
A Comparative Analysis
Generalized Epileptiform Spike & Wave Discharge
Traditional Default EEG Settings:
Paper Speed: 30 mm/sec
Sens: 7 µV/mm HF: 70 Hz LF: 1 HzPatient is Awake with Eyes Open. Bipolar Double Banana Montage, No clinical signs of seizure or behavior change.
Reformatted to Sleep Settings
• Now how might this look different in the
format recommended by the new AASM
Sleep Scoring Guidelines?
• The Guidelines recommend the following
settings:
– Sensitivity: 7 µV/mm (or 10 µV/mm)
– HFF: 35 Hz
– LFF: .1 Hz
– Paper Speed: 10 mm/sec
• AASM Guidelines Montage
– The Guidelines recommend referencing to
contralateral mastoid.
– This patient was recorded with A1 & A2
placed on the ears, so this is one deviation
from the recommendations.
• F3 – A2
• F4 – A1
• C3 – A2
• C4 – A1
• O1 – A1
• O2 – A2
Reformatted to Sleep Settings
• Let’s change one parameter at time to
assess the impact of each individual setting
on this discharge
• The first change will be a reduction in the
High Filter to 35 Hz.
• Spikes are defined as having a duration of
20 – 70 msec.
• This means the frequency of Spikes would
be 14 Hz – 50 Hz (Time\Duration =
Frequency)
• A High Filter setting of 35 Hz will attenuate
some spikes in the higher frequency.
Reformatted to Sleep Settings
Generalized Epileptiform Spike & Wave Discharge
Deviation From Traditional Default EEG Settings:
Paper Speed: 30 mm/sec
Sens: 7 µV/mm HF: 35 Hz LF: 1 HzPatient is Awake with Eyes Open. Bipolar Double Banana Montage, No clinical signs of seizure or behavior change.
Let’s Look At These Side By Side:
Not That Different, Right?HFF: 70 Hz HFF: 35 Hz
• The next change will be to reduce the Paper
Speed to 10 mm/sec from the EEG setting of 30
mm/sec.
• In the EEG format ten seconds per page are
displayed.
• In the Polysomnography format thirty seconds
per page are displayed.
Reformatted to Sleep Settings
Generalized Epileptiform Spike & Wave Discharge
Deviation From Traditional Default EEG Settings:
Paper Speed: 10 mm/sec
Sens: 7 µV/mm HF: 35 Hz LF: 1 HzPatient is Awake with Eyes Open. Bipolar Double Banana Montage, No clinical signs of seizure or behavior change.
Reformatting to Sleep Settings
• Where are the spikes???
• I was reviewing this and began to doubt I had clipped the same point in time.
• To verify we were comparing apples to apples, let’s use the eye movements to validate this is the same place in the record.
• In addition, I’ve blown up the Sleep Record to line up the second divisions.
• No question we are looking at the same time in the record.
• Also, notice the change in alpha activity over the O1 & O2 Head Regions.
Paper Speed: 30
mm/sec
Paper Speed: 10
mm/sec
• The source of this data loss exists in two
possible sources
– Sampling Rate
– Screen Resolution
• The Sampling Rate of this recording
• The Screen Resolution of the system this
was reviewed on was
Reformatting to Sleep Settings
• Now let’s go back to the default EEG Settings
and change ONLY THE MONTAGE to the
AASNM Scoring Montage.
• Paper Speed will be 30 mm/sec as it is in
Clinical EEG.
Reformatted to Sleep Settings
Generalized Epileptiform Spike & Wave Discharge
Deviation From Traditional Default EEG Settings:
Paper Speed: 30 mm/sec
Sens: 7 µV/mm HF: 70 Hz LF: 1 Hz
AASM Montage (A1\A2 Used Instead of M1\M2)Patient is Awake with Eyes Open. Bipolar Double Banana Montage, No clinical signs of seizure or behavior change.
Nothing Noteworthy Here
Generalized Epileptiform Spike & Wave Discharge
Deviation From Traditional Default EEG Settings:
Paper Speed: 30 mm/sec
Sens: 7 µV/mm HF: 70 Hz LF: 1 Hz
AASM Montage (A1\A2 Used Instead of M1\M2)Patient is Awake with Eyes Open. Bipolar Double Banana Montage, No clinical signs of seizure or behavior change.
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Conclusions
Patients with nocturnal events with normal or
equivocal routine day EEG should have either
Sleep EEG with extended polysomnographic
monitoring, or
Sleep study with extended EEG monitoring
SLEEP? STUDY?