11: Levels of Consciousness & Epilepsy Flashcards
What is the Reticular Activating System?
Set of connected nuclei in the brain responsible for regulating:
- Wakefulness
- Sleep-wake transitions
Where is the Reticular Activating System located?
Brainstem
What are the 2 groups of the Reticular Activating System?
- Ascending RAS
- Inhibitory Area
What does the Activating RAS do?
Activates the brain to attention
What does the Inhibitory of the RAS do?
Decreases activity of higher brain → alters levels of consciousness
How does the RAS act?
By releasing these neurotransmitters into the CSF:
- Ach
- Serotonin
- Dopamine
- Noradrenaline
Changes in the levels of these hormones is seen in changes in the conscious levels in the sleep / wake cycle
Other than normal sleep / wake cycle changes, what can changes in the RAS hormones indicate?
Different diseases e.g mood disorders / cognitive ability disorders (depression / schizophrenia)
What is Electroencephalography (EEG)
Measures the activity of the cortex (and hence hormone release)
What is the electrical activity of REM similar to?
Electrical activity of the awake brain
Picture: The black bit at peak of each curve is REM
What are the 4 types of EEG waves in the brain?
- Alpha = @ relaxed wakefulnes (awake but eyes closed)
- Beta = @ mental activity + attention
- Theta = @ drowsy state & 1st stage of sleep
- Delta = @ deep sleep
What does RAS (aka ascending arousal system) dysfunction lead to?
Impaired consciousness
What is epilepsy an umbrella term for?
Umbrella term for seizures / seizure syndromes
What is epilepsy?
Brain disorder characterised by:
Periodic unpredictable seizures
Caused by rhythmic firing of groups of neurones
What are the signs and symptoms of epilepsy? (3 things)
- Temporary confusion
- Uncontrolled jerking movements
- Loss of consciousness / awareness
What are the 3 types of seizures?
- Focal (Partial) Seizures
- Generalised Seizures
- Status Epilepticus
What is the difference between Focal (Partial) and Generalised Seizures?
Focal (Partial) = affects only one hemisphere / lobe of brain
Generalised = affects both hemispheres
Generaliseddd like affect whole brain in generallll
What are the 2 types of Focal Seizure?
- Simple Partial
- Complex Partial
What are the features of a Simple Partial Seizure? (5 things)
- Affects only small part of brain
- Patient remains conscious
- Patient experiences strange sensation (hearing / smelling something)
- Jerking movemenets
* 5. Can develop into a Complex Partial Seizure*
Remember them from brain to consciousness down to ears and nose down to limbs
What are the features of Complex Partial Seizures? (1 thing)
- Impaired consciousness / awareness
What are the 6 types of Generalised Seizures?
- Tonic
- Atonic
- Clonic
- Tonic-Clonic
- Myoclonic
- Absence
TACTMA (like talk to me)
What are the features of a Tonic Generalised Seizure? (2 things)
- Muscles → stiff / flexed
- Patient falls backwards
What are the features of an Atonic Generalised Seizure? (2 things)
- Muscles → Relax / Floppy
- Patient falls forwards
What are the features of a Clonic Generalised Seizure? (1 thing)
Violent muscle contractions (convulsions)
What are the features of a Tonic-Clonic Generalised Seizure? (1 thing)
Period of tonic then clonic seizures
