Epilepsy: Insights into Consciousness

Obligatory Historical Quote:“Men ought to know that from the brain, and from the brain only, arise our pleasures, joys, laughter and jests, as well as our sorrows, pains, griefs and tears...

Madness comes from its moistness. When the brain is abnormally moist, of necessity it moves, and when it moves neither sight nor hearing are still, and the tongue speaks in accordance with the things seen and heard on any occasion.

But when the brain is still, a man can think properly.

- Hippocrates, ~ 5th Century B.C.

Circuitry of the Brain

Circuitry of the Brain• ~100 billion neurons with ~ 200 trillion

contacts between them

Pathology of Circuits

Definitions:

• Seizure:– An uncontrolled, excessive, and hypersynchronous

discharge of cortical neurons

A sudden involuntary, time limited alteration in behavior… accompanied by an abnormal electrical discharge in the brain.

• Epilepsy:– The tendency to have recurrent, non provoked

seizures. Classify seizures into different types of disease

Seizures Vs. Epilepsy• A seizure is a symptom (like a fever)

- Infection, Traumatic Brain Injury, Electrolyte imbalance, drugs, nutritional, etc

Types of Seizures

• Classify by the brain areas involved (and EEG):– Partial Seizure: • Arise from a delimited brain region• Can be Simple (no impairment of awareness) or • Can be Complex (have impairment of awareness)

– Generalized Seizure• Involves the whole brain• Can have impaired awareness (Absence) or• Can have motor involvement (Tonic-Clonic/Grand Mal)

Examples of Seizures:

Videos of Seizures:

Absence Seizure: https://www.youtube.com/watch?v=BzIs8YeafZM

Gelastic Seizure: https://www.youtube.com/watch?v=ICvNGo2j-9M

Myoclonic Seizure: https://www.youtube.com/watch?feature=endscreen&NR=1&v=3epEL8sX-PM(As part of a a syndrome: Dravet Syndrome: Severe Myoclonic Epilepsy of Infancy)

Tonic-Clonic Seizure (Grand Mal): https://www.youtube.com/watch?v=83UvqwJoStc

Localizing Seizures:• Aura:– Visual: See spots, stars, blobs, etc

• Occipital cortex– Auditory: Hear music, voices, ringing, etc

• Superior temporal cortex– Olfactory: Smell burning, etc

• Medial temporal lobe (Uncinate cortex)– Fear:

• Medial temporal lobe (Amygdala)– Sexual: Erotic feelings, inappropriate arousal

• Medial Temporal lobe

Treatment

• Acute Management

• Long-Term Management (Drugs)

• Surgical Management

Medical Management: Drugs• Most anti-epileptics affect channels or

neurotransmitters:– Sodium, Calcium, Chloride, GABA

Medical Management: Drugs

• 60-70% of patients can be successfully treated– Generalized seizures typically easier to control

than partial seizures– Can consider weaning medication if seizure free

(except in certain cases)

• Most common cause of treatment failure is noncompliance

When All Else Fails: Brain Surgery

• Options:– Focal resection: (I will focus on this)– Hemispherectomy– Partial Corpus Callosotomy

• Selection Criteria:– Refractory to medical therapy ( failed 3 or more

drugs with different mechanisms of action)– Imaging suggests progressive disorder

Surgical Options

• It’s scary, but:– Consider the alternatives:• Living in constant risk: Driving, Heights, Water,

Fire/Burns, Tools, etc.

– In Texas must be 6 months seizure free to drive

• Current surgical techniques only ~ 20 years old: Why?– High resolution MRI, EEG, ECoG, Cortical Stimulation

Surgical Techniques

Localizing Seizures: Cortical Stimulation Mapping

Localizing Seizures:Electrocorticography (ECoG)

Research Opportunities:

• Unparalleled opportunity to study brain function:– Intracranial electrodes offer the best of EEG and fMRI

to Identify and study the eloquent cortex

• Making surgery safer for future patients– What NOT to cut!

Functional Brain Mapping

Functional Brain Mapping

Functional Connectivity

Brain Computer Interface (BCI)• “Woman with Quadriplegia Feeds Herself

Chocolate Using Mind-Controlled Robot Arm”– https://www.youtube.com/watch?v=C7H_M8-dBHc

Questions?

Treatments: