[12.29] Sleep Physiology V2

State of awareness of self and environment that gives significance to stimuli

What is the definition of consciousness?

Arousal and cognitive functions

What are the two components of consciousness?

Ascending Reticular Activating System (ARAS)

What system subserves arousal?

Cerebral Hemisphere

What part of the brain is responsible for cognitive functions?

Respond back (blinking, moving hand, verbally answering)

How can a patient demonstrate they are conscious?

A response to the environment or outside stimulus

What needs to be present for a patient to be considered conscious?

Derangement of consciousness

What happens if either arousal or cognitive functions are affected?

Acuity, time-frame, and tempo

How is altered consciousness differentiated between acute and subacute?

Clouding, Delirium, Obtundation, Stupor, Coma, Locked-in

List six examples of acute altered consciousness from Table 1.

Dementia, Hypersomnia, Abulic, Akinetic mutism, Minimal Consciousness, Vegetative, Brain death

List seven examples of subacute or chronic altered consciousness from Table 1.

Basis Pontis

What structure is usually severed in Locked-in syndrome?

Ventral tegmental areas

What specific area is severed in Locked-in syndrome affecting pontine fibers?

Facial muscles and extremity muscles

What muscles are affected in Locked-in syndrome?

Bilateral corticospinal tract

What tract transverses the bilateral basis pontis?

Quadriplegia

What is the state where a patient cannot move all extremities, tongue, and face?

Eyes up and down and blink

What movements can a patient with Locked-in syndrome still perform?

CN III

Which cranial nerve is unaffected in Locked-in syndrome, allowing up and down eye movement?

Trapped in our own body while still being conscious

How is the state of Locked-in syndrome described?

Responding to environmental stimuli through blinking

How do patients with Locked-in syndrome respond to the environment?

CN VII, CN VI, corticospinal fibers, medial lemniscal pathway

Which cranial nerves and pathways are affected in Locked-in syndrome causing inability to move eyes laterally?

A state where the patient cannot respond to stimuli

What is the definition of coma?

Verbal, noxious, painful stimuli

What types of stimuli does a patient in a coma not respond to?

Verbal, eye-movement, motor movement

In what forms can a patient in a coma not respond?

Metabolic Coma and Structural Coma

What are the two types of coma?

Non-neurologic coma

What is another name for Metabolic Coma?

Reversible if inducing factors are identified and addressed

What is a key characteristic of Metabolic Coma if its cause is treated?

Metabolic conditions

What causes Metabolic Coma?

Hypoglycemia

Give an example of a metabolic condition where giving sugar can reverse the coma.

Hyponatremia, Hypoxia, Hepatic encephalopathy

List three other metabolic conditions that can cause coma.

Accumulation of ammonia in the brain

What causes Hepatic encephalopathy?

Liver transplantation

What procedure can help excrete ammonia and potentially reverse coma in Hepatic encephalopathy?

Neurologic coma

What is another name for Structural Coma?

Pathology located in the brain

Where is the cause of Structural Coma located?

Usually irreversible

What is a key characteristic of Neurologic based comas?

Bilateral Cerebral affectation, Diencephalic structures

What are two examples of causes of Structural Coma?

Bilateral Stroke, Meningitis affecting all lobes, Encephalitis, Infection of all brain parenchyma

List examples of Bilateral Cerebral affectation causing coma.

Thalamus affected bilaterally

What specific diencephalic structure affected bilaterally can lead to coma?

Decrease in thalamocortical projections

How does bilateral thalamic affectation lead to coma?

Dense network along brainstem

Where is the Ascending Reticular Activating System (ARAS) located?

Maintain consciousness, arousal, and awakeness

What are the functions of the ARAS?

Hemorrhages affecting the brainstem and/or cerebral hemispheres

What can cause damage to the ARAS?

Difficult to pinpoint

How is the location of the ARAS described in literature?

Monoaminergic system put together (Monoaminergic + Cholinergic systems)

What does Dr. Porlas believe the ARAS consists of?

Ability to respond to stimuli of varying intensity by speech, eye opening, and motor movements

How can consciousness be assessed?

Glasgow Coma Scale (GCS)

What scale is used to assess patient consciousness based on scoring?

University of Glasgow

Where was the Glasgow Coma Scale proposed?

GCS 15 (E4, V5, M6)

What is the best response score on the GCS?

GCS 3 (E1, V1, M1)

What is the lowest score on the GCS, indicating coma?

GCS 11 (E4, V1, M6)

What would be the GCS score for a patient with Broca's aphasia?

Postural changes due to noxious stimuli

What does Dr. Porlas not count when a patient is in a coma on the GCS?

Vegetative function

What are reflex movements considered part of?

Primitive reflexes

What type of reflexes are vegetative function reflexes?

Checking the brainstem for function through reflexes

How can consciousness be assessed in comatose patients besides GCS?

Pain affliction on comatose patients

What method is used on comatose patients to assess consciousness via brainstem reflexes?

Pressing down on the supraorbital nerve, using a pencil on the nail bed, sternal rub, compressing the tragus

List four methods of pain infliction mentioned to assess consciousness.

ARAS and cerebral hemispheres

Where does consciousness reside?

Higher cortical function, Mental status

How can the consciousness of the cerebral hemispheres be checked?

Reflexes situated in the brainstem

How is the ARAS assessed?

Brainstem failure

What is indicated if all brainstem reflexes are not present?

CN II (Afferent), CN III (Efferent)

What are the afferent and efferent limbs of the Pupillary Light Reflex?

CN VIII (Afferent), CN III, IV, VI (Efferent)

What are the afferent and efferent limbs of the Oculocephalic and Vestibuloocular Reflexes?

CN V(I) (Afferent), CN VII (Efferent)

What are the afferent and efferent limbs of the Corneal Reflex?

CN VIII (Afferent), CN VII (Efferent)

What are the afferent and efferent limbs of the Auditopalpebral Reflex?

CN IX (Afferent), CN X (Efferent)

What are the afferent and efferent limbs of the Gag Reflex?

False

Are patients with locked-in syndrome not conscious?

Metabolic Coma and Structural Coma

What are the two types of comas?

True

Is compressing the tragus a method for consciousness assessment?

CN V(I) (Afferent) and CN VII (Efferent)

What are the afferent and efferent limbs of the corneal reflex?

Electroencephalogram (EEG)

What is a means of recording brain electrical activity by attaching electrodes to the scalp?

Hans Berger

Who invented the EEG?

36-lead electrodes

How many electrodes are typically attached to the scalp for an EEG according to the source?

Cortical functioning and activity throughout the consciousness system

What information does the EEG provide?

Brain rhythms

What is a basis for sleep observed on EEG?

Beta

What brain rhythm is associated with being awake, normal, alert, and consciousness?

14 Hz

What is the frequency range for Beta waves?

Alpha

What brain rhythm is associated with being relaxed, lucid, calm, and not thinking?

8-13 Hz

What is the frequency range for Alpha waves?

Theta

What brain rhythm is associated with deep relaxation, meditation, and mental imagery?

4-7 Hz

What is the frequency range for Theta waves?

Delta

What brain rhythm is associated with deep, dreamless sleep?

1-3 Hz

What is the frequency range for Delta waves?

An altered state of consciousness necessary for the well-being of the organism

How is sleep defined in the source?

Highly organized and regular process divided into stages

How is sleep characterized?

Electroencephalogram (rhythm), Electrooculogram, and Electromyogram (muscle tone)

What three measurements are used to define the stages of sleep?

Decreases

How does the amount of time spent sleeping change as we age?

16 to 20 hours a day

What is the total sleep time for a newborn baby?

10-12 hours

What is the total sleep time for a child?

0 to 10 hours

What is the total sleep time for a mid-adolescence?

~7 to 7.5 hours

What is the total sleep time for a young adulthood?

Tulog manok

What Filipino phrase is used to describe the sleep pattern of the elderly, waking up early?

Sleep cycle

What is one of the observed patterns of sleep?

70 minutes to 100 minutes

How long does a sleep cycle last?

To ensure we don't wake up during Stage 4 of sleep

Why is it suggested to time sleep duration in intervals divisible by 90 minutes?

Our sleep would not be restorative

What happens if we wake up during Stage 4 of sleep?

Stage 1 or REM

During which stages of sleep can we choose to wake up for a better experience?

14 Hz

What is the EEG frequency during the Awake state?

Myogenic artifacts (muscle and eye movements)

What artifacts are present during the Awake state?

14 Hz per second

What is the EEG frequency during REM sleep?

No myogenic artifacts

What artifacts are typically absent during REM sleep?

Rapid eye movement (darting up and down)

What characterizes eye movement during REM sleep?