Transcript Epilepsy & TBI - Sterman-Kaiser Imaging Laboratory

What is Epilepsy
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Over-responsiveness to brain state changes
and to transient sensory stimuli
• Seizure triggers:
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Sleep deprivation
Stress
Drugs or alcohol
Menstrual cycle
Nutritional deficiencies, low blood sugar
Other meds
Hyperventilation
Flashing lights or sounds
• (like from a video game or TV –
1991 Pokemon)
• i.e., Transitions
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Associated with cortical or subcortical
hyperexcitability
History of the “Falling Sickness”
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4th century account of epileptic attack differs little
from current textbook description of a
generalized tonic-clonic seizure:
• "After various premonitory signs the patient falls down,
stretched out or twisted, and in this condition he
remains for some time. After these tonic convulsions he
passes into the stage of clonic convulsions and a
condition where he appears to be sleeping. The attack is
followed by complete amnesia."
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Guainerius in 1516 recommended placing an
object between the teeth of a person undergoing
a convulsion.
The Sacred disease
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Mohammed is
reported to have
had seizures since
age 3 and to have
said, "This is a
common affliction
of prophets, of
whom I wish to be
counted as one."
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St Paul
Julius Caesar
Napoleon
Tolstoy
Socrates
Numerous
painters, writers
composers,
leaders…
Joan D’Arc
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Joan often felt that the secrets of the universe
were about to be revealed to her
Seizures were triggered by ringing church bells.
• A musicogenic TLE, with ecstatic aura.
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Musicogenic epilepsy is generally triggered by
particular music which has an emotional
significance to the individual.
Joan's voices (St Catherine) and visions propelled
her to become an heroic soldier in the effort to
save France from English domination. She was
burned at the stake as a heretic when she was 19
years old in 1431.
Fyodor Dostoyevsky
on TLE
'You are all healthy people, but
you have no idea what joy that joy is
which we epileptics experience the
second before a seizure... I do not
know whether this joy lasts for
seconds or hours or months, but
believe me, I would not exchange it
for all the delights of this world.'
» continue...
Temporal Lobe Epilepsy Sx
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Interictal traits
• Hypergraphia
• Hyperreligiosity
• “Stickiness” or clinginess
• Altered interest in sex
• Undirected and transient aggressiveness
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Perhaps due to Amygdala overactivation,
which acts as a brake on engagement
Common Myths
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Seizures cause additional brain damage… Not usually
• Single tonic-clonic seizures lasting 5-10 minutes are not
thought to cause brain damage.
• However, more frequent and prolonged tonic-clonic
seizures may in some patients injure the brain.
Epilepsy is a life-long disorder for all – not always.
• Half of childhood epilepsies are outgrown by adulthood.
• When a person has been free of seizures for 1 to 3
years, medications can be slowly withdrawn and
discontinued under a doctor's supervision.
Seizure disorder is another term for epilepsy (clarity
of definition, not a myth per se)
Epilepsy Causes
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1 in 200 people suffer epilepsy
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Many cases have no known cause.
• Head injuries, such as MVA or fall.
• Brain tumor or stroke
• Arteriosclerosis (fatty plaque buildup)
• Pre/natal brain injury
(anoxia/hypoxia)
• Infections-meningitis or
encephalitis
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Brain damage causes "scar" on
brain. This is where a seizure
starts. It is unknown why a scar
starts a seizure.
Causes
• Genetic factors
• Metabolic abnormalities
Types of Epilepsy
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Generalized seizures (most common) -
uncontrollable neural discharge starts in one area that spreads
across brain.
• Muscle twitches and convulsions
• Loss of consciousness and loss of recall about seizure.
• Tonic-clonic ("grand mal“ - great sickness) seizure - massive
discharge. Rigidity and violent jerking of body. "Tonic-clonic"
= "stiffness-violent."
• Absence ("petit mal") seizure - nonconvulsive., person
unaware of surroundings, may stare off in space or freeze
for 5 to 10s.
• Myoclonic seizure - Seizure involves motor cortex and causes
twitching or jerking of certain parts of the body.
• Status epilepticus – Frequent lengthy seizures without
regaining consciousness between attacks. Requires
immediate medical attention.
Example: Absence or Petit Mal
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Absence seizures
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Loss or diminution of normal activity.
Staring and loss of responsiveness
Occasionally subtle motor activity – flutters, jerks.
May go unrecognized for years or be mistaken as daydreaming
or ADD.
“Spells” (seizures) last ~10 s, dozens of times daily. No
recollection of events during seizures and resumes previous
activity without any postictal symptoms.
EEG classically shows intermittent runs of generalized
3 cps spike and wave activity which may be precipitated by
hyperventilation.
Petit Mal: 3 Hz spike and wave
VHS Brain #30 –
Another example of Petit Mal
Types of Epilepsy
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Partial Seizures - abnormal electrical activity
involving small part of brain (sometimes speads).
• Simple partial seizures (or "Jacksonian" or "focal"
seizures)
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Short-lasting seizures without loss of consciousness.
Often see, hear or smell something strange.
Part of the body may jerk.
• Complex partial seizures
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Seizure with a change, not loss, in consciousness.
People may hear or see things, or memories may
resurface. Feelings of deja vu common.
Example: complex partial seizure
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Symptoms
• Staring & guttural vocalizations in 8y
• EEG: Awake and asleep EEG reveals frequent spikewave discharges localized to left temporal lobe near
T3 electrode
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Diagnosis: Asymmetric motor manifestations
(facial grimace, post-ictal unilateral weakness)
suggest focal origin.
• Presence of altered consciousness indicates complex
partial rather than simple partial.
Complex partial seizure
Focal discharge
Generalized discharge
Hyperventilation is performed over a 3 minute period to
induce absence seizures. Often bilateral slow waves are
induced by hyperventilation.
Attempt to induce seizure with stroboscopic stimulation
NORMAL: Small evoked occipital potentials. Photic driving responses
are time locked to each flash of light at same frequency or half the
frequency (subharmonic). Photic driving responses begin and end
simultaneously with the onset and cessation of photic stimulation.
Photoconvulsive seizures
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Seizures induced by photic stim; more common for generalized
epilepsy. Not time locked to photic stim, may begin later than
onset and persist after; different frequency
Also possible, photomyoclonic responses
Epilepsy Treatment and Control
• Drugs (first mode of attack anticonvulsants)
• Surgery (“last” resort)
• Novel therapies
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Neurofeedback (30 y record, not so novel)
Diet
Exercise
Vasal stimulation
Traumatic Brain Injury (TBI)
Clinical EEG evaluation
(subjective & requires extensive
training of the “eyeball”)
• Activity characterized by
shape and frequency
• Transients & background
• x2 interhemispheric power
asymmetry indicates
abnormality
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Cortical potentials are 5001500 uV, but 5-50 uV at scalp
Assess severity & depth of coma
• initial EEG more abnormal,
more predictive at 24-48 hrs
• Reactivity to sound & pain - ~1 billion neurons per electrode
somatosensory potentials
• Sleep reorganization
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EEG & GCS used to make initial diagnosis and treatment recommendations
Frontal intermittent rhythmic delta activity
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Occipital IRDA in children
Normal during hyperventilation, increases with
drowsiness
Images from http://www.neuro.mcg.edu/amurro/cnphys/
Diffuse slowing
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cerebral dysfunction from multifocal
or diffuse brain disease.
Polymorphic focal slowing (< 8 Hz).
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Unlike FIRDA, does not change during drowsiness.
Abnormality indicates structural brain lesion and the site of
this abnormality localizes the brain lesion.
Closed Head Injury:
Coup and Contrecoup
TBI: 1 in 400 people in USA
Leading cause of children's
death and 60% of all
traumatic deaths
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Prehistoric trephination to
relieve pressure
Glasgow Coma Score (GCS)
• Best Eye Response. (4)
• 1 No eye opening.
• 2 Eye opening to pain.
• 3 Eye opening to verbal
command.
• 4 Eyes open spontaneously.
• Best Verbal Response. (5)
• 1 No verbal response
• 2 Incomprehensible sounds.
• 3 Inappropriate words.
• 4 Confused
• 5 Oriented
• Best Motor Response. (6)
• 1 No motor response.
• 2 Extension to pain.
• 3 Flexion to pain.
• 4 Withdrawal from pain.
• 5 Localizing pain.
• 6 Obeys Commands to act.
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HIGHER IS BETTER
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GCS 13+ correlates with
a mild brain injury,
9 to 12, moderate injury
8 or less, a severe TBI
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E3V3M5 = GCS 11.
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Cerebral
Ischemia
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Occurs when CBF falls below metabolic
demands of tissue
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At CBF 15 ml/100g/min, synaptic
transmission ceases and EEG flattens.
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• Cellular integrity preserved (membrane ion
pumps and ion gradients) until lower flows.
• Loss of electrical activity is protective, reduces
energy expenditure of cell.
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Isoelectric -- CBF must be restored to avoid
neurologic injury.
• At 6 to 10 ml/100g/min, extracellular
potassium concentrations increase and cell
death follows
Detected and
classified by EEG
• Mild - isolated
reduction in amplitude
of fast activity
• Moderate - amplitude
reduction and
concomitant slowing
• Severe - loss of fast
activity with
predominant delta
activity or isoelectricity
(Matthew) EEG Grades with TBI
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Grade I - Alpha rhythm with beta and some theta
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Grade II - Predominant theta waves with some
alpha, beta, and delta waves
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Grade III - Predominant delta waves mixed with
some theta waves
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Grade IV - Delta waves, occasionally isoelectric
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Grade V & VI – Burst-suppression (isoelectric)
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Grade VII - Isoelectric
Grade IV
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Anterior 8-12 Hz activity unresponsive to stimulation
Poor prognosis
Grade V or VI
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Periodic bursts of high voltage slow waves and spikes
that occur between low voltage periods
Poor prognosis
Grade VII
Isoelectricity
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Electrocerebral inactivity:
8+ channels, 30 min recording, proper
equipment sensitivity.
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In addition, technician touches each
electrode to verify integrity of recording
system and stimulate patient to see if EEG
activity occurs.
• Non-cerebral potentials (pulse and EKG)
may be present.
• Indicates brain death, but also posisble
in drug overdose and hypothermia.