Electroencephalography and Epilepsy Speaker Donald L ... · Electroencephalography and Epilepsy...

Electroencephalography and EpilepsySpeaker Donald L. Schomer, M.D.

1The screen versions of these slides have full details of copyright and acknowledgements

Electroencephalography and Epilepsy

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Donald L. Schomer, M.D.Professor, Neurology, Harvard University

Director, Laboratory of Clinical NeurophysiologyChief, Comprehensive Epilepsy ProgramBeth Israel Deaconess Medical Center

Past President, American Clinical Neurophysiology SocietyPast President, American Academy of Clinical Neurophysiology

Past Chairman, American Board of Clinical NeurophysiologyEditor, Niedermeyer’s Electroencephalography, 6th Edition

EEG recording in patient’s with suspected seizures and/or epilepsy

A. Generalized (Genetic) Epilepsy

B. Symptomatic Generalized Epilepsy 1. Hypsarrhythmia

2. Lennox-Gastaut syndrome

3. Neurodegenerative disorders

Lecture outline

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g

C. Focal or partial seizures and/or epilepsies1. Classical temporal lobe seizure

2. Occipital lobe seizure

3. Limbic, sub-temporal seizure

4. Symptomatic focal seizure

D. Other EEG findings of unclear significance

E. Other useful ancillary recording techniques

EEG - overview of use in epilepsyRoutine and telemetric EEG

• Routine Electroencephalogram– Standard recording

– Standard recording using activation procedures

– Standard recording with special electrodes

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– Prolonged in-lab recordings

• Telemetry-based recording– Hospital based

Standard or non-invasive recordings

With invasive electrodes

– AmbulatoryWith or without audio/video recording



EEG-overview of use in epilepsyRoutine EEG

Routine Electroencephalogram

• Standard recording

– Subject’s head is measured for identification for the placement of standardized electrodes

– Electrodes are attached using paste or glue

S f ( )

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– Standard electrode connections are used for recordings (montages)

– Recordings are preformed for 30 to 60 minutes understand conditions

Eyes open on request

Eyes closed on request

Subject will hyperventilate for up to 3 minutes, if clinically appropriate (HV)

Subject is allowed to fall asleep, if tired

Subject is stimulated with a photic stimulator using standardized protocols (IPS)

EEG-overview of use in epilepsyRoutine EEG (2)

EOR

Fp1-F3F3-C3C3-P3P3-O1

Fp1-F7F7-T3T3-T5T5-O1


Fp2 F8

5Note display montage: 1) Request to “open eyes”

2) Alpha rhythm-blocking effect of maneuver

Fp2-F8F8-T4T4-T6T6-O2Fz-CzCz-Pz

EogL-A1EogR-A2

K2-k1

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EEG-overview of use in epilepsyRoutine EEG (3)

ECR




6Note display montage: 1) Request to “close eyes”

2) Re-emergence of the alpha rhythm


EogL-A1EogR-A2

K2-k1


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Fundamentals of recording EEG Routine activating techniques - hyperventilation

(mm

Hg)

(mm

Hg)

• Hyperventilation is usually done for 3 minutes during the course of a routine EEG

• As shown on the right hand side of the slide, partial pressures of pO2 and pCO2

are graphed along the time course of the procedure

• Time course and magnitude of absolute pCO2 and pO2 changes with 3 minutes

7Niedermeyer’s Electroencephalography: Basic Principles, Clinical Applications and Related Fields, Eds. DL Schomer and FL da Silva, 6th Edition, Wolters Kluwer, 2010, Chapter 12, T Takahashi and KH Chiappa

Cha

nge

in p

O2

(

Cha

nge

in p

CO

2(

Time (min)

pO2pCO2

pCO2 and pO2 changes with 3 minutes of hyperventilation in nine normal adult subjects are demonstrated

• The error bars are 1 standard deviation

• A transcutaneous heated membrane technique was used for the blood gas measurements

• Note the late changes in these values, which do not normalize for up to 10-12 minutes after the exercise is discontinued

EEG-overview of use in epilepsyRoutine EEG - hyperventilation



Fp2-F4

Begin HV

8 See request to start hyperventilating

pF4-C4C4-P4P4-O2


EogL-A1EogR-A2

K2-k1


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EEG-overview of use in epilepsyRoutine EEG – hyperventilation (2)



Fp2-F4F4-C4

Stop HV Start PostHV + 3:00'

9 See request to cease hyperventilating

C4-P4P4-O2


EogL-A1EogR-A2

K2-k1

H2-gnd

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EEG-overview of use in epilepsyRoutine EEG - intermittent photic stimulation

• During the course of a routine EEG, intermittent photic stimulation (IPS) is performed under standard condition

• The subject is first told that IPS will be obtained and how the procedure is done

• A photic stimulator is placed directly in front of the relaxed and resting subject at a distance of 1 meter

• The subject is asked to keep their eyes closed during this portion of the study

• They are told that a bright flashing light will be used

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y g g g

– The technologists then triggers the stimulator to flash at a set frequency for approximately 10 seconds

– The subject then has 10 seconds without stimulation

– The stimulus is repeated at different frequencies

– Usually frequencies of 1, 2, 3, 4, 6, 8, 10, 12 ,15, 20, 25, 30 and 35 Hz are used, although some frequencies may be repeated or given for a slightly longer duration

– If there is a discharge that occurs, the technologists are trained in the decision making about repeating the stimulus or stopping the procedure

– In some seizure disorders, the IPS may trigger an overt convulsion

• This procedure may be repeated using colored light filters

EEG-overview of use in epilepsyRoutine EEG - intermittent photic stimulation (2)



Fp2-F4F4-C4C4-P4

11IPS on at 8 Hz. IPS off IPS on at 10 Hz. IPS off

P4-O2Fp2-F8

F8-T4T4-T6T6-O2Fz-CzCz-Pz

EogL-A1EogR-A2

K2-K1Ref-gnd

30.0uVH2-gnd

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EEG-overview of use in epilepsyRoutine EEG - intermittent photic stimulation (3)



Fp2-F4F4-C4C4-P4P4 O2

12IPS on at 18 Hz. IPS off IPS on at 20 Hz. IPS off

P4-O2Fp2-F8

F8-T4T4-T6T6-O2Fz-CzCz-Pz

EogL-A1EogR-A2

K2-K1Ref-gnd

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Fundamentals of recording EEGRoutine - intermittent photic stimulation

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Generalized photo-paroxysmal responses elicited by regional red flicker stimuli in a 14-year old girl with photosensitive epilepsy

Niedermeyer’s Electroencephalography: Basic Principles, Clinical Applications and Related Fields, Eds. DL Schomer and FL da Silva, 6th Edition, Wolters Kluwer, 2010, Chapter 12, T. Takahashi and KH Chiappa

Fundamentals of recording EEG Variations on intermittent photic stimulation

14Niedermeyer’s Electroencephalography: Basic Principles, Clinical Applications and Related Fields, Eds. DL Schomer and FL da Silva, 6th Edition, Wolters Kluwer, 2010, Chapter 12, T Takahashi and KH Chiappa

Photic Stim.

Generalized paroxysmal discharges elicited by a video game and generalized photo paroxysmal response (PPRs) elicited by flickering stimuli in a 13-year-old photosensitive epilepsy patient; Full-field stimuli of a 15-Hz red flicker and a 25-Hz flickering dot pattern provided by use of square-type strobe-filter method elicited type 4 PPR

EEG recording in suspected seizures/epilepsy Routine activating techniques - sleep

• Polyspikes in light non rapid-eye-movement (REM) sleep,especially over central region, associated

15Niedermeyer’s Electroencephalography: Basic Principles, Clinical Applications and Related Fields, Eds. DL Schomer and FL da Silva, 6th Edition, Wolters Kluwer, 2010, Chapter 27, BS Chang, DL Schomer and E Niedermeyer

with K complexes; This is an example of sleep activation; (Reproduced with permission from AMA Archives of Neurology)



Fundamentals of recording EEG Additional electrodes

• An additional set of electrodes can be applied further down (caudal) to the lateral array over what would be considered the posterior portion of the anterior part of the temporal lobe; This corresponds to the anterior portion of the middle temporal gyrus; These electrodes have standardized positions and are referred to as T1 and T2; Very similarly positioned electrodes are over the zygomatic prominences

• An additional entire array of electrodes may be placed further caudal to the lateral temporal array; These electrodes are called sub-temporal electrodes and together are called th b t l h i Th d f iddl d l t l/i f i t l i

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the sub-temporal chain; They record from middle and lateral/inferior temporal gyri and more inferior aspects of the lateral occipital lobes

• Sphenoidal electrodes require a physician to place them; They are place such that they either approach to foramen ovale or reside slightly deeper into the masseter muscles from the T1 and T2 electrodes; These are shown in a later slide

• Naso-ethmoidal electrodes are rarely used; They are firm metallic electrodes that are placed into the nasal passages, directed upward and rest on the cribiform plate; These electrodes allow the recording to be extended to cover more frontal polar regions and potentially anterior and inferior frontal regions; An example is also shown on the next slide

• Nasopharyngeal electrodes are also shown on the next slide but are currently used in very few centers world wide because of their tendency to be very artifact prone

Fundamentals of recording EEGSpecial electrodes - NPs and NEs

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Naso-pharyngeal electrodes

Naso-ethmoidal electrodes

Fundamentals of recording EEGSpecial electrodes - sphenoidal electrodes

• The more anterior placed sphenoidal electrode is placed by a trained physician, under local anesthesia, close to the formen ovale, shown on the left

• The more posterior placement, shown on the left, has never actually become

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, ypopular due the rather significant amount of discomfort associated with its placement

• Often an AP or base view skull x-ray is required to insure accurate placement; The fine silver wire variant of this electrode can often be left in place for several days of recording for monitoring purposes



Fundamentals of recording EEGSpecial electrodes - sphenoidal electrodes (2)

• Phantom image of the head showing a 22-gauge carrier needle entering the skin (concentric target lines, S) in front of the condylar process of the mandible passing under the zygomatic arch (Z) and through the mandibular notch (MN),

19Niedermeyer’s Electroencephalography: Basic Principles, Clinical Applications and Related Fields, Eds. DL Schomer and FL da Silva, 6th Edition, Wolters Kluwer, 2010, Chapter32, AM Kanner, T Stoub and S Bild

Reprinted with permission from Kanner AM, Ramirez L, Jones JC., J. Clin. Neurophysiol. 1995; 12: 72–81

g ( ),en route to V3 emerging from the foramen ovale (FO, seen on the edge); PP denotes the pterygoid plate; The SE that is mounted on the superior surface of the needleis not shown

EEG - overview of use in epilepsy

Telemetry-based recording

• The purpose of prolonged EEGs is to capture the EEG on the subject while they are having clinical symptoms

– Hospital basedPhase I testing

– AmbulatorySubject has a recording device attached and usually goes home

ith it f i bl i d

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– Subjects are admitted to specialized units where EEG and audio/video recording are done

– If they are on medication, it can be selectively removed under observation

– They may undergo additional activations as noted above, i.e., sleep deprivation, PS, HV

– They have standard electrodes with or without non-invasive additional electrodes

Phase II testing with invasive electrodes (see later discussion)– Foramen Ovale electrodes

– Strips or grids

– Depth electrodes

with it for a variable period

The recorders can be attached to audio/video recording equipment to link those signal to the EEG

EEG recording in suspected generalized seizures/ epilepsy genetic and/or symptomatic based

• Seizures or epilepsy syndromes that are generalized are often genetically based or related to disorders that effect the neurons of the brain in a diffuse manner, which may be acquired or genetic in origin; The later condition is referred to as a symptomatic state;

• In the genetically based syndromes, the seizure may have markers for the disorder that can be seen on routine EEG studies; These markers vary considerably and a few of them will be demonstrated in the following slides; Seizures, which represent the time when the patient is experiencing their symptoms, can also vary considerably

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is experiencing their symptoms, can also vary considerably from one syndromic disorder to another;

• If a patient has “symptomatic” epilepsy, the routine EEG often demonstrates other abnormalities, in addition to the markers for the seizures themselves; This may take to form of diffuse or multifocal abnormalities in the background rhythms, abnormal responses to hyperventilation or intermittent photic stimulation;

• The electrical phenomena, in either situation tend to be seen over all or most regions of the brain, when they occur;

• There are situations where both generalized and focal abnormalities can be present in the same subject



EEG recording in suspected seizures/epilepsyGeneralized seizure disorders - childhood absence epilepsy

• Absence epilepsy with generalized-synchronous spike wave discharge with a frequency at the onset of 3.0 Hz that slows to about 2.5 Hz near the end f th di h

1. Fp1-F32. F3-C33. C3-P34. P3-O1

5. Fp2-F46. F4-C47. C4-P48. P4-O2

9 Fp1 F7

22Niedermeyer’s Electroencephalography: Basic Principles, Clinical Applications and Related Fields, Eds. DL Schomer and FL da Silva, 6th Edition, Wolters Kluwer, 2010, Chapter # 27, BS Chang, DL Schomer and E Niedermeyer

09:36:291 sec100 uV

09:36:34 09:36:39

of the discharge; The enormous amplitude of the discharges necessitates considerable lowering of the display gain; The frontal voltage maximum is evident;Also note gradual decline of the spike component at the end of event

9. Fp1-F710. F7-T311. T3-T512. T5-O1

13. Fp2-F814. F8-T415. T4-T616. T6-O217. AuxA18. AuxB

EEG recording in suspected seizures/epilepsyGeneralized seizure disorders - juvenile myoclonic epilepsy



Fp2-F4F4-C4

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C4-P4P4-O2


EogL-A1EogR-A2

K2-K1

Juvenile Myoclonic Epilepsy (JME) is also associated with sudden, high amplitude generalized discharges, similar to Absence Epilepsy; However, these discharges tend to be somewhat faster, with a frequency of 4.0 -6.0 Hz and have polyphasic discharges as demonstrated above

EEG recording in suspected seizures/epilepsy Generalized seizure disorders - Jeavon’s syndrome




F 2 F8

24Jeavon’s Syndrome is associated with somewhat similar discharges to the JME Syndrome; Patient’s with this condition have eye-closure related activation of their discharges, causing eye lid myoclonus and occasional generalized myoclonus and more rarely generalized tonic-clonic convulsions


EogL-A1EogR-A2

K2-K1Ref-gnd

30.0uVH2-gnd



EEG recording in suspected seizures/epilepsyGeneralized seizure disorders

1. Fp1-F3

2. F3-C3

3. C3-P3

4. P3-O1

5. Fp2-F4

6. F4-C4

7. C4-P4

8. P4-O2

9 Fp1 F7

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9. Fp1-F7

10. F7-T3

11. T3-T5

12. T5-O1

13. Fp2-F8

14. F8-T4

15. T4-T6

16. T6-O2

19:02:141 sec

100 uV

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Patients with Generalized Tonic-Clonic seizures with have an onset as noted here; There is often a discharge at the onset, followed by EEG de-synchronization, followed by a buildup of generalized rhythmic activity associated with the clinical behavior

EEG recording in suspected seizures/epilepsyGeneralized seizure disorders — symptomatic

• Generalized convulsion can occur in infancy; Such a pattern is shown here in “Early Infantile Myoclonic Encephalopathy”; This 3-month old

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patient has burst-suppression-like activity that alternates with mixed slow background activity some of which is intermingled with slow and spike discharges and stretches of background flattening

Niedermeyer’s Electroencephalography: Basic Principles, Clinical Applications and Related Fields, Eds. DL Schomer and FL da Silva, 6th Edition, Wolters Kluwer, 2010, Chapter 26, DR Nordli, JJ Riviello, E Niedermeyer

EEG recording in suspected seizures/epilepsyGeneralized seizure disorders — symptomatic (2)

• In the slightly old infant, the “Infantile spasms” are seen with the EEG pattern called “hypsarrhythmia”;

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pattern called hypsarrhythmia ;In this 8-month-old patient, please note the high-voltage characteristics of the background and posterior voltage maximum of the spikes

Niedermeyer’s Electroencephalography: Basic Principles, Clinical Applications and Related Fields, Eds. DL Schomer and FL da Silva, 6th Edition, Wolters Kluwer, 2010, Chapter 26, DR Nordli, JJ Riviello, E Niedermeyer



EEG recording in suspected seizures/epilepsyGeneralized seizure disorders - Lennox-Gastaut syndrome

28Niedermeyer’s Electroencephalography: Basic Principles, Clinical Applications and Related Fields, Eds. DL Schomer and FL da Silva, 6th Edition, Wolters Kluwer, 2010, Chapter 27, BS Chang, DL Scomer, E Niedermeyer

A run of rapid spikes in a 19-year-old patient with the Lennox–Gastaut syndrome; This often follows a patient who had a hypsarrhythmia EEG pattern associated with clinical spasms; Note anterior maximum of the discharge; A few slow spike-wave complexes are also seen in the right temporal occipital region

EEG recording in suspected seizures/epilepsyGeneralized seizure disorders - Lennox-Gastaut syndrome

Common EEG findingsFp1-F3F3-C3C3-P3P3-O1

Fp2-F4F4-C4C4-P4

GI Seizure

29This is a slow spike and wave pattern seen frequently in the chronic Lennox-Gastaut Syndrome

P4-O2Fp1-F7

F7-T3T3-T5T5-O1

Fp2-F8F8-T4T4-T6T6-O2K2-K15.0uV

EEG recording in suspected seizures/epilepsy Symptomatic seizure disorders - Niemann-Pick disease

30Niedermeyer’s Electroencephalography: Basic Principles, Clinical Applications and Related Fields, Eds. DL Schomer and FL da Silva, 6th Edition, Wolters Kluwer, 2010, Chapter 15, J Gaitanis

A genetic disorder with a deficiency of acid sphingomyelinase and the intraneuronal accumulation of sphingomyelin; Patients develop a progressive loss of function with changes in intellect and progressive myoclonic seizures



EEG recording in suspected seizures/epilepsy Symptomatic seizure disorders - Retts syndrome


Female disorder of early childhood with a subacute mental and physical decline with dementia, loss of motor skills and severe seizures; Shown here is a case with severe background slowing and multifocal interictal discharges

EEG recording in suspected seizures/epilepsy Symptomatic seizure disorders - Angelman’s syndrome


Most cases of this disorder are due to a gene deletion that effects GABAa receptor function; The EEG pattern is similar to hypsarrhythmia pattern with severe background abnormalities and multifocal interictal discharges

EEG recording in suspected focal onset seizures“Partial” seizure disorders

• “Partial” seizures or the “Partial Epilepsy Syndromes” are synonymous with focal onset seizures

• Since the seizures have origin in a specific area or local of the brain, the first signs or symptoms of the event itself often suggest the area where the seizure starts; This is a very helpful clue regarding the possible area of origin

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• Focal seizure may remain focal, spread to other areas or regions of the brain or evolve into generalized convulsions; These issues are dealt with extensively in later talks

• It is important to remember that there are significant limitations to routine EEG or routine EEG monitoring; Some seizures may come from regions of the cortex that have little or no representation in the routine recordings or even with the addition of special electrodes; Those cases will also be discussed in later talks



EEG recording in focal seizuresPartial seizure - interictal discharges

• Partial seizures with often have markers for their presence in the form of focal interictal discharges

• Shown here is a patient with an age related focal epilepsy called “Benign Rolandic Epilepsy”

34Niedermeyer’s Electroencephalography: Basic Principles, Clinical Applications and Related Fields, Eds. DL Schomer and FL da Silva, 6th Edition, Wolters Kluwer, 2010, Chapter 26, DR Nordli, JJ Riviello, E Niedermeyer

• This tracing shows the coexistence of rolandic interictal spikes and physiological vertex waves in light sleep in an 8-year-old boy with attacks of abdominal pain

• Right centroparietal spikes with occasionalspread to the left are marked with an “X” and typical examples of a vertex wave are marked with an “O”

EEG recording in suspected focal seizuresPartial seizure - interictal discharges



Fp2-F4F4-C4C4 P4

35Computer algorithms are also frequently employed to detect interictal discharges, as demonstrated in this page of computer detection on a patient with right temporal lobe onset epilepsy

C4-P4P4-O2


EogL-A1EogR-A2

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EEG recording in suspected focal seizuresPartial seizure - interictal discharges (2)



Fp1-F7

36Computer algorithms are also frequently employed to detect interictal discharges, as demonstrated in this page of computer detection on a patient with right temporal lobe onset epilepsy


Fp2-F8F8-T4T4-T6T6-O2K2-K1K3-K4



EEG recording in focal seizuresPartial seizure - focal temporal onset



Fp2-F4F4-C4

37Onset – phase reversals at F7

C4-P4P4-O2


EogL-A1EogR-A2

K2-K1 Ref-gnd

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EEG recording in focal seizuresPartial seizure - focal occipital onset



Fp2-F4F4 C4

38Occipital onset seizure – Maximum activity at O1

F4-C4C4-P4P4-O2


EogL-A1

EEG recording in focal seizuresPartial seizure - focal subtemporal onset




Fp2-F8F8-T4T4-T6

39Onset – phase reversals at T10

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T6-O2Fp1-F9F9-T9T9-P9P9-O1

Fp2-F10F10-T10T10-P10P10-O2

Fz-CzCz-PzE1-T9

E2-T10K1-K2K3-K4

Cz-gnd



EEG recording in focal seizuresSymptomatic seizure – mitochrondrial encephalopathy

with lactic acidosis (MELAS)

40Niedermeyer’s Electroencephalography: Basic Principles, Clinical Applications and Related Fields, Eds. DL Schomer and FL da Silva, 6th Edition, Wolters Kluwer, 2010, Chapter # 15, by J Gaitanis

Ongoing seizure

EEG recording in suspected seizures/epilepsyOther findings of unclear significance

Psychomotor Variant -

6 Hz. Spike and wave burst -

Mu rhythm -

Small sharp spike, benign epileptiform transients of sleep -

Mid-temporal, bilateral and independent, young to middle age

Highest amplitude frontal-central, drowsiness and light sleep, children and adults

Central location, resting rhythm of motor-sensory cortex, blocked with contra-lateral hand movements

Anterior and mid temporal, mainly adults, small and very sharp

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transients of sleep

Wickets -

14-6 Hz discharges -

Midline theta (Ciganek rhythm) -

Subclinical rhythmic EEG discharges in adults (SREDA) -

and very sharp

Temporal location, 6-11 Hz, adults

Posterior temporal, 14 or 6 Hz. discharges, mainly children

Midline (Cz, Fz) and parasagittal, 4-7 Hz, children and adults

Temporal and parietal regions, older adults, many last secondsto minutes, without obvious clinical effect

Niedermeyer’s Electroencephalography: Basic Principles, Clinical Applications and Related Fields, Eds. DL Schomer and FL da Silva, 6th Edition, Wolters Kluwer, 2010, Chapter 14, JC Edwards and E Kutluay

EEG recording in suspected seizures/epilepsyOther findings of unclear significance - psychomotor variant

Fp1-F3

F3-C3

C3-P3

P3-O1

Fp2-F4

F4-C4

C4 P4

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C4-P4

P4-O2

Fp1-F7

F7-T3

T3-T5

T5-O1

Fp2-F8

F8-T4

T4-T6

T6-O2



EEG recording in suspected seizures/epilepsyOther findings of unclear significance - psychomotor variant

(2)Cz-C3C3-T3T3-T1T1-T2T2-T4T4-C4C4-CzFz-Fz


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P3 O1Fp1-F7F7-T3T3-T5T5-O1Cz-Cz



EEG recording in suspected seizures/epilepsyOther findings of unclear significance - 6 Hz. spike and wave

• A short run of 6/sec spike waves, posterior type, recorded in a 52-year-old

44Niedermeyer’s Electroencephalography: Basic Principles, Clinical Applications and Related Fields, Eds. DL Schomer and FL da Silva, 6th Edition, Wolters Kluwer, 2010, Chapter 14, JC Edwards and E Kutluay

woman with a history of head injury 2 years earlier and subsequent headache, dizziness, and memory loss; There was computed tomography (CT) scan evidence of cortical atrophy

EEG recording in suspected seizures/epilepsyOther findings of unclear significance - Mu rhythm



Fp2-F4F4-C4

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C4-P4P4-O2


EogL-A1EogR-A2

K2-K1

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Ref-gnd30.0uV

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EEG recording in suspected seizures/epilepsyOther findings of unclear significance - small sharp spikes

• Small sharp spikes (51-year-old patient); Note the subtle character and moderate voltage of the discharge;


also note its predominance in the left nasopharyngeal lead; There is evidence of spread into T3, as well as into the right nasopharyngeal lead; The left section was recorded in the waking state (transition to earliest drowsiness); the middle and right sections were recorded in sleep

EEG recording in suspected seizures/epilepsyOther findings of unclear significance - Wickets


EEG recording in suspected seizures/epilepsyOther findings of unclear significance - 14-6 Hz. discharges

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Examples of 14/sec and 6/sec positive spikes (underlined); Note posterior predominance for this pattern and shifting asymmetrics; Also note the sometimes blurred distinction between the 14 and 6 components, due to notch formation; The recording was obtained from a 12-year-old patient; montages to ipsilateral ear

Niedermeyer’s Electroencephalography: Basic Principles, Clinical Applications and Related Fields, Eds. DL Schomer and FL da Silva, 6th Edition, Wolters Kluwer, 2010, Chapter 14, JC Edwards and E Kutluay



EEG recording in suspected seizures/epilepsyOther findings of unclear significance - midline theta


EEG recording in suspected seizures/epilepsyOther findings of unclear significance - SREDA


EEG recording in suspected seizures/epilepsyOther findings - cardiac rhythm changes

Cz-C3C3-T3T3-T1T1-T2T2-T4T4-C4C4-CzFz-Fz


Fp1-F7F7-T3T3 T5

51Recording shows a patient going from an atrial based arrhythmia to ventricular tachycardia

T3-T5T5-O1Cz-Cz


Fp2-F8F8-T4T4-T6T6-O2Pz-Pz

EKG



EEG recording in suspected seizures/epilepsyOther findings - cardiac asystole

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Patient had a brief clinical epileptic seizure followed by a cardiac asystolefor 35 seconds that was associated with diffuse changes on the EEG;The patient had spontaneous resumption of their cardiac rhythm

SaO2 abnormalities1.Cz-C32.C3-T3

3.T3-Sp14.Sp1-Sp2

5.Sp2-T46.T4-C47.C4-Cz

8.EOG9.Fp1-F710.F7-T311 T3 T5

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11.T3-T512.T5-O1

13.Fp2-F814.F8-T4

16.SaO2

10:17:36Min 96%

10:19:16Min 95%

10:20:56Min 96%

10:22:36Min 87%

10:24:16Min 0%

10:25:56Min 0%

10:27:36Min 85%

10:29:16Min 81%

10:30:56Min 85%

18AuxB

1 sec100 uV

This is a compressed EEG; The patient experienced a brief seizure noted above; This occurred early in the recording; The patient then went on to become profoundly hypoxic with O2 saturations down from normal of 94% to the mid 60%; All the while, he was relatively unaware of this phenomena; This event lasted several minutes before his O2 saturations gradually returned to normal

90 %

Summary and conclusions• Routine EEGs are for 30 or more minutes in duration and include opening and closing the eyes

on command, hyperventilating for approximately 3 minutes and intermittent photic stimulation

• Additionally, EEG may be done or hours or days in an attempt to capture EEG during epileptic seizures

• The EEG is useful in correlating behavioral events with the brain’s electrical activity; The EEG may give additional information about the presence of localized or wide-spread abnormalities that may be of clinical significance

• Non-EEG physiological recordings may prove useful, too; Cardiac or respiratory disorders may mimic seizures or encephalopathies

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• When recording EEGs in the diagnosis or management of patients, there are markersfor the epileptic potential which can be recorded; These asymptomatic phenomena are called “interictal” discharges

• Interictal discharges can be relatively diagnostic in some cases, but are more commonly a predictor of inherited versus acquired and/or ideopathic forms of epilepsy

• Symptomatic recordings show “ictal” changes; These changes can vary significantly depending on the biology of the underlying seizure disorder and can be predictive of the patient’s clinical behavior

• Many non-epileptic EEG phenomena may masquerade as epileptic events to the non-trained and experienced clinician



Acknowledgments

Thank you• The audience for your kind attention

• The good people at Henry Stewart Talks

• Professor Steven Schachter M D

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• Professor Steven Schachter, M.D.

• Special thanks to all of my mentors and my students; Both have taught me about the exciting fields of “Brain Physiology” and “Epilepsy”

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Electroencephalography and Epilepsy Speaker Donald L ... · Electroencephalography and Epilepsy...

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