Disorders of consciousness

Tornóci László

Semmelweis University

Institute of Pathophysiology

Consciousness is special

• speech (language)

• foresight

• tool making

• free will

• helping others

• empathy

• sense of morality

This is the only topic in our subject which doesn’t apply to animals.

Other things thought to be unique to humans:

(distribution of work, living in a ‘society’ is observed in animal species)

There is increasing evidence that these are biologically based,so not as much unique to humans, as we may like to believe.

Elements of consciousness in animals

•Separation of body and environment

•Ability to communicate (sign language)

•Ability to count

•Ability to decieve others, „to lie”

Wild minds

What animals really think?

• subjective feeling (somewhere in the head)• no specific center has been found

corresponding to this sensation (this would be the home of our soul, according to some)

• sSome expert say self consciousness is an illusion (Daniel C. Dennett, Susan Blackmore)

Self consciousness

We can get information about the self consciousness of another person only indirectly, mostly by attempting to

communicate with him/her.

Suggested book about memes,evolution and nature of consciousness

Consciousness has two components

• level (quantity, arousal or vigility)

the brain is active (‘turned on’)• content (quality)

the brain functions (clear thinking)

Disorders of consciousness

• quantitative (impaired arousal)

• qualitative (impaired content)

Impaired arousal causes disorder of content,but impaired content is possible with normalarousal.

Quantitative disorders of consciousness

• obtundation (impaired perception, slow reactions)• somnolence (the patient falls asleep, but can be

waken up)• stupor (the patient can be waken up by strong

stimuli, for a few seconds only)• coma (the patient cannot be waken up by any

means)brain death (flat EEG, cardiorespiratory support needed)

Coma like syndromes

• vegetative state (seemingly awake patient, normal wake-sleep cycles, no cardio-respiratory support needed, but no cortical function)

• locked-in syndrome (selective deefferen-tation, pseudocoma: patient may move the eyes)

• catatonia (psychiatric disorder)

Qualitative disorders of consciousness

• confusion (lack of clarity in thinking, illusions, hallucinations may occur)

• delirium (agitated, hypersympathotonic state with hallucinations)

Often due to alcohol/drug withdrawal.

• other psychiatric disorders

Sleeping

• Sleeping provides rest, regeneration• Sleeping saves energy, when we cannot do

anything useful (hibernation)• Only the brain needs sleeping, during which it is

in a special state

Sleeping, is dangerous because we are unconscious!

Why do we sleep?

Sleeping disorders

• Insomnia• stress, bad habit, drug effect, depression, mania, restless legs

syndrome etc.

• Hypersomnia• narcolepsy (sleepy during the day, bad sleep during the night,

cataplexy, persistent sleep paralysis, hypnagogue hallucinations)• depression (light deprivation)

• Parasomnias

Parasomnias

• somnambulism• bruxism (grinding of the teeth)• pavor nocturnus (night terrors)• enuresis nocturna

Current interpretation of sleep paralysis: abduction by aliens

• Wake up to be paralyzed, unable to defend oneself

• Feeling the presence of others in the room

• Sliding with the bed, buzzing sound, lights above (operation)

• Sexual intercourse

Interpretation of sleep paralysis/night terrors in the middle age

Succubus: sexually desirable witch

Incubus: creature sitting on the chest

Henry Fuseli (1741-1825)

Interpretation of sleep paralysis/night terrors in the middle age