Sleep Flashcards
how is sleep described in relation to consciousness
- easily reversible state of inactivity with a
- lack of interaction with the environment
what can unconsciousness be
coma (depressed state of neural activity)
sleep (VARIATION in neural activity)
what are the three states of consciousness
- wakefulness (alert, detect object and pays attention)
- core consciousness (wakefulness and emotional responses, simple memory)
- extended consciousness (all plus self awareness, autobiog memory, language and creativity)
what are some suggested functions of sleep
processing, storage of memories
recuperation of bodies immune system
conserve energy
does the sleeping brain consume oxygen
yes
what are the two main forms of externally discernable sleep
REM (rapid eye movement side to side)
non REM
how do you measure neuronal activity
EEG
electroencephalogram
how does the EEG work
post synaptic activity of SYNCHRONISED DENDRITIC ACTIVITY can be picked up
-individual neurons cannot
EEG electrode is connected to an amplifier EEG
read through layers to cells in cortex
only detect massive synchronised depolarisation- causes BIGGER DEFLECTION
how do you get synchronisation
either by neuronal interconnections or by pacemaker
the more neurons that are synchronised, the bigger the peaks on the EEG
are the neurons active during sleep
yes
sleeping brain consumes oxygen as much as wakeful brain
why do you get small and rapid depolarisations on EEG
brain working-not much synchronisation
lots of individual AP flying around
doing their own thing
lots of sparks
coincidence if depolarising at the same time
therefore small and rapid movements of trace
become synchronised during sleep
induced by pacemaker
why do you get small and rapid depolarisations on EEG
brain working-not much synchronisation
lots of individual AP flying around
doing their own thing
lots of sparks
coincidence if depolarising at the same time
therefore small and rapid movements of trace
become synchronised during sleep
induced by pacemaker
how is the EEG arranged
and how does it work
19 (+) pairs
at internationally agreed points on the surface of the head.
comparison between the pairs provides a coarse picture of the neuronal activity in various areas
separate different stages of sleep (REM and non REM) and further 4 stages
what are the EEG defined stages of sleep
and how many cycles in one sleep
AWAKE
STAGE 1
STAGE 2
STAGE 3
STAGE 4
REM
repeat around 5 REM sleeps per night
drowsy to deep sleep takes about 1 hour
minimum time between REM sleep about 30 mins
what are the EEG defined stages of sleep
and how many cycles in one sleep
AWAKE
STAGE 1
STAGE 2
STAGE 3
STAGE 4
REM
repeat around 5 REM sleeps per night
drowsy to deep sleep takes about 1 hour
minimum time between REM sleep about 30 mins
describe the awake stage
eyes closed ALPHA high frequency
eyes open BETA waves
high frequency and lower amplitude waves
describe the awake stage
eyes closed ALPHA high frequency
eyes open BETA waves
high frequency and lower amplitude waves
describe stage 1
THETA waves
easily roused
slow rolling eye movements
high amplitude
slower frequency
describe stage 2
Begin K complexes
fairly fast firing
high amplitude
some bursts of activity of synchronisation
no eye movement but body movements remain possible
SPINDLES- prelude to deep sleep
harder to rouse
describe stage 3
slower frequency DELTA waves
harder to rouse
few spindles
not regular
increased synchronisation
describe stage 4
biggest amplitude
biggest entrainment
deepest sleep and hardest to arouse
DELTA waves
lower heart rate and blood pressure
movement 15-30 min period
describe REM sleep
fast BETA waves and REM
easier to rouse than in stage 4
almost awake state
DREAMING-brain become very active
low muscle tone (very floppy- no movement)
if woke up from this you will remember dream you had
what controls the passage of stages
reticular formation (brainstem)
PINEAL GLAND— allows us to have a diurnal rhythm
describe the sequence of the thalamus on brain waves
during day
reticular formation EXCITED
causes depolarisation
to thalamus (stays depolarised and active)
–non rhythmic output
INCREASED AROUSAL (alpha and beta waves)
sleep hygiene pattern kicks in/tired
reticular formation inhibited
hyperpolarise the thalamus
produce rhythmic output
slow EEG waves in cerebral cortex
–slow waves
what is the broad definition of epilepsy
continuing tendency to have RECURRENT, UNPROVOKED SEIZURES
rare risk of sudden death SUDEP
what are sleep spindles
characterisation on NREM
found with k complexes in STAGE 2
what are sleep spindles
characterisation on NREM
found with k complexes in STAGE 2
what may cause SUDEP
probs from electrical disruption in heart -AF - heart attack
how do you diagnose epilepsy
EEG- INTERICTAL period between seizures there are still characterisitcs of some types of epileipsy
history taking important (including from observers)
what are some relevant features of epilepsy
PRE- aura/ warning/ fear/ deja vu
abnormal movements (lip smacking, patting, stroking)
POST- memory loss, confusion, headache
wounds/ scares? from falls
usually interictal exam is normal
what are the classification of epileptic seizures
FOCAL
-focal aware
-focal unaware
can develop into->
GENERALISED
-absence- typical/atypical
-myoclonic
-clonic
-tonic
-clonic-tonic
-atonic
UNCLASSIFIED
what are focal aware seizures
consciousness is preserved in positive or negative symptoms
symptoms are related to AREA AFFECTED IN BRAIN
person is aware
what can focal aware symptoms include
PRIMARY MOTOR CORTEX
-simple clonic movements
PREMOTOR AREAS
-elaborate motor output
VISUAL ASSOCIATION
-faces or complex scenes
OCCIPITAL LOBE
-contralateral visual hallucinations
AUDITORY CORTEX
-roaring or underwater hearing
ASSOCIATIVE AUDITORY CORTEX
-music
TEMPORAL
-visceral discomfort, odour, anxiety, fear
ALL OFTEN preceded by an AURA
- can progress to generalised seizures
what is a focal unaware seizure
there can be impairment of consciousness - can’t tell you about particular symptoms
1-2 mins
start w aura
unresponsiveness
automatisms
autonomic responses (tachy, pupil dilation)
post ictal headache then confusion
can evolve into generalised seizures
auras then seen as prelude
what is the most common type of focal unaware seizure
TEMPORAL (40%)
damage to hippocampus pyramidal cells (long processes- easy to damage)
if small stroke/physical damage
get scar tissue which acts a focus for origin of seizure
what are absent generalised seziures
PETIT MAL
most typical:
short period
sudden
abrupt cessation
may be associated with mild clonic jerking of eyelids
no recollection
atypical:
loss of posture
autonomic phenomena
automatisms
characteristic 2.5-3.5 Hz spike and wave pattern
DIFFERANCE FROM FOCAL UNAWARE– second is LONGER
what are generalised seizures
both hemispheres affected
manifestations of seizure are determined by cortical site at which seizure arises
present in 40% of al epileptic syndromes
ALWAYS alteration to consciousness
what are myoclonic seizures
myoclonic jerking
-treated differently depending on type
IF GENERALISED different medication for juveniles
not focal leading to generalised
what are atonic seizures
sudden loss of postural tone
most often in children- rare
what are tonic clonic seizures
GRAND MAL
major convulsions with rigidity and jerking
slows over 60-120 sec followed by stuporous state (post ictal depression)
what drug should you not give juveniles if they are having a myoclonic seizure (generalised)
CARBAMAZEPINE
what is status epilepticus
more than 30 mins of continuous seizure
two or more sequential seizures spanning without recovery between seizures
med emergency
tonic-clonic cycle
may also already have heart problems
are all seizures epilieptic
no
can be caused by:
withdrawal
diabetic instability
blow to head
what non-invasive tests can you use to support a diagnosis of a seizure
ECG - check for abnormal cardiac problems- SUDEP, arrhythmias, athersclerosis
EEG- interictal EEG
—- INTERICTAL EPILEIPTFORM ACTIVITY
CT- looking for brain shrinkage, brain not formed properly- focal areas where seizures may have started
MRI- scarring, reduced perfusion (fmri), dysplasia, cortex damage
RESOLUTION BETTER
What is interictal epileptiform activity
large electrophysiological events observed between seizures in patients with epilepsy.
characteristic waves and spikes to predict type of epilepsy
what are attack triggers and pre-disposition of epilepsy
PRE-DISPOSITION
-scar tissue
-developmental issues
-pyramidal cell damage
-sub-optimal regulation of neuronal excitability
DISEASE
-tumours
TRIGGERS
-tired
-alcohol
-drugs (anti-depres)
change of meds
what do anti- epileptic dugs (AED) do
decreases frequency/ severity of seizures in people with epilepsy
treat SYMPTOMS, not cause
GOAL– max QofL by minimising seizures and adverse drug effects
what are the targets for AED
suppress excitatory NT- inhibit Na VOLTAGE DEPENDENT system/ Ca– RAPID DEPOLARISATION IS SUPPRESSED
enhance inhibitory NT system-GABA
increase outward positive K
many are PLEIOTROPIC
what does pleiotropic mean
they act via multiple mechanisms
what AEDs act primarily on Na channels
PHENYTOIN, CARBAMAZEPINE
-block voltage dep sodium channels at high firing freq
but reduce efficacy of contraceptive pill
OXCARBAZEPINE
-blocks volt depen NA at high freq
-also effect K+ channels
pleiotropic effect
ZONISAMIDE
-blocks volt-depen Na channels and T-type Ca channel
LAMOTRIGINE
-inhibit voltage sensitive Na channels
-best starting drug
what drug do you only use for absence generalised seizures
ETHOSUXIMIDE
what is an issue with sodium valproate
can be teratogenic
what is an issue with carbamazepine
enzyme inducing effects- many interactions
what do both vigabatrin and tiagabine do
GABA enhancer
what can you use for focal onset and focal leading to generalised
carbamazepine
lamotrigine
oxcarbazepine
sodium valproate
levetiracetam
what should you use for generalised seizures
valproic avid
lamotrigine
topiramate
what treatment can you use for status epilepticus
diazepam, lorazapam intra veinous (fact acting)
- GABA agonist
then
phenytoin, phenobarbital when there is contorl
what is satus epilepticus
more than 30 mins of continuous seizure activity
two + sequential seizures spanning this period with no full recovery between
med emergency
