Epilepsy

Question 1

seizure

Answer 1

• occasional, excessive, unprovoked discharge of nerve tissue on muscles
• can alter consciousness, sensation, and behaviour
• Seizure is technically the activity going on in the brain (relies on EEG); convulsion is the behavioural manifestation (ie. Tonus (rigidity), clonus (tremors))
• • Pre-ictal, interictal, and post-ictal activity

Question 2

epilepsy

Answer 2

• recurrent unprovoked seizures (at least 2 seizures on 2 separate days with 24-hour period separating them)
• due to atypical, excessive, or synchronous neuronal activity in the brain
• Reflex epilepsy: some specific activity triggers seizures (ie. Brushing teeth)
• Intractable epilepsy: does not respond to treatment/medication

Question 3

epileptic aura (and why it’s important)

Answer 3

• Intense moment right before seizure arrives, indicating that a seizure is imminent (ex. A certain feeling, smell, etc.)
• Important for 2 reasons:
• • They warn the epileptic of an impending seizure
• • The nature of the aura is predictive of the epileptic focus (the place where it starts before it spreads, can be helpful for surgical treatment/removal)

Question 4

focal seizures

Answer 4

• start in one brain area and stay in that area (ie. Motor cortex seizure)
• • Simple partial seizure: symptoms are primarily sensory or motor or both; typically no loss of consciousness (ie. Mouth twitching during seizure, but no loss of consciousness)
• • Complex partial seizure: patients engage in compulsive, repetitive, simple behaviours (automatisms) and more complex behaviours that can appear perfectly normal; disruption and/or alteration of consciousness is common (ie. Tugging at shirt)

Question 5

generalized seizures

Answer 5

• involves entire brain
• Secondary generalization: when a focal seizure evolves into a generalized seizure
• Types:
• • Absence seizure (“petit mal”): no significant convulsion. Primary symptoms are: loss of consciousness, cessation of ongoing behaviour, vacant look, fluttering eyelids
• • Tonic-clonic (“grand mal”): muscle rigidity and tremors; loss of consciousness and equilibrium; tongue-biting, urination, and cyanosis are also common

Question 6

4 types of seizures

Answer 6

• Simple partial (focal)
• Complex partial (focal)
• Absence seizure (generalized)
• Tonic-clonic (generalized)

Question 7

Risk factors for epilepsy: specific examples

Answer 7

• Vascular (ex. malformations)
• Congenital (ex. family history and genetics)
• Trauma (ex. head trauma)
• Tumor (ex. in CNS)
• Degenerative (ex. neurodegeneation)
• Infection
• Cryptogenic/idiopathic (no apparent mechanism; vast majority of cases)

Question 8

Immediate vs. Early vs. Late Seizures

Answer 8

• Immediate seizures = occurring within 24 h after injury
• Early seizures = occur less than 1 week after injury
• Late seizures = occur more than 1 week after injury
• Latent period = time between injury and onset of late seizures

Question 9

Overlapping risk factors

Answer 9

• Overlapping risk factors for early and late seizures indicate that we don’t really know what’s causing it (ie. Intracranial hematoma, post-traumatic amnesia, depressed skull fractures)
• Glasgow Coma Scale score of 3-8 (3 is almost comatose)

Question 10

potential mechanisms of epileptogenesis (post-TBI)

Answer 10

• overabundance of glutamate being released due to TBI damage -> leads to excitotoxicity (cellular loss), tau, and increased calcium
• tau interacts with free radicals to reduce the threshold for seizures
• to much calcium leads to excessive apoptosis

Question 11

Comorbidities

Answer 11

• People with epilepsy are more likely to experience the following co-existing medical conditions:
• • Diabetes
• • Major depressive disorder
• • Anxiety disorders
• • Migraine headaches
• • Stroke
• • Heart disease
• • Asthma
• • Arthritis
• • Suicide

Question 12

3 common treatments for epilepsy

Answer 12

• Anticonvulsants
• Vagus Nerve Stimulation
• Ketogenic Diet

Question 13

less common treatments for epilepsy

Answer 13

• Cannabidiol treatment (weakly binds to endocannabinoid receptors, positive anecdotal/case study evidence)
• Surgical procedures (for severe intractable epilepsy)

Question 14

Treatment: Anticonvulsants

Answer 14

• can lessen frequency and severity of seizures, but do not cure epilepsy
• Side effects can impact motor and cognitive speed, memory, mood, and psychosis

Question 15

Treatment: vagus nerve stimulation

Answer 15

• Putting pacemaker style pulse generator in chest to stimulate vagus nerve and prevent overactivity
• Only moderately effective

Question 16

Treatment: ketogenic diet

Answer 16

Increases ketones, which may be beneficial

Question 17

Surgical procedures

Answer 17

• treatment for severe intractible epilepsy only
• Prior to surgery, electrodes are sometimes inserted into/onto the cortex to find the epileptic focus (“subdermal grids”)
• • These electrodes are very helpful in research (ex. “The Halle Berry neuron” -> finding out that some neurons are responsible for categories)

Question 18

What are the most likely locations of Epileptic Focus?

Answer 18

• Epileptic focus is much more likely to be found in the frontal or temporal lobes than other parts of the cortex
• Why? Research has shown that regions associated with learning and memory are more likely to have an epileptic focus

Question 19

Cartesian Dualiasm (Hustvedt article)

Answer 19

• Notion proposed by Descartes that the human mind and body are seperate entities (gap between pysche and soma)
• Generally rejected by current neuroscientists, but still present in the field through terms like “psychogenic” (due to psychic/mental factors and not to detectible somatic/organic factors)

Question 20

psychogenic non-epileptic seizures (PNES) vs. epilepsy (Hustvedt article)

Answer 20

• epilepsy = organic disease
• PNES = functional disorder (no physical site of injury can be found)
• • ex. headaches, recurrence of add semlls, shortness of breath, fatigues, and seizures

Question 21

why does philosophy matter in modern psychological science? (Hustvedt article)

Answer 21

• philosophy informs diagnosis

- - terms like “functional” and “organic” reflect less nuanced understandings of biological processes

Question 22

implications of psychogenic vs. organic debate for neuroscientists (Hustvedt article)

Answer 22

neurologists/medical professions must examine their implicit prejudices against psychogenic/emotional/psychiatric
illnesses as less “real” simply because they have no apparent physical cause

Question 23

state of research in TBI (Mahler study)

Answer 23

• fairly limited
• most research done on cohort of select TBI patients -> difficult to generalize
• few population-based cohort studies done; those done have lots of attrition, no validation of TBI diagnosis, or include young patients only

Question 24

Mahler study: key points

Answer 24

• population based study
• suggests risk of epileptic seizures is increased 2x after mild TBI and 9x after severe TBI
• 5x-6x greater risk after isolated intracranial hemorrhage or contusion; combination of the two leads to 43x increased risk
• During first 6 months after severe TBI, risk increased 50x
• risk is still increased >10 years after trauma

Question 25

Mahler study: methods and results

Answer 25

• looked at patients newly identified with an unprovoked seizure or epilepsy, used statistical analyses to determine relative risk regarding different combinations of head injuries and time intervals after trauma
• risk of epilepsy higher afer severe TBI, combined head injuries, and within first 6 months post-trauma (and remains elevated for >10 yrs)

Question 26

ictal spikes

Answer 26

Seizures have characteristic form of EEG activity -> commonly measured by inter-ictal spikes (distance between spikes/pulses)