Lecture: Consciousness from a medical perspective

Question 1

Two components of consciousness in the medical sense

Answer 1

1. Awareness (Purposeful behavior in response to environment)
2. Arousal (Is awake)

Question 2

Two components of a mental state

Answer 2

• Consciousness content (qualitative aspect or awareness)
  nothing noticed – normal perception – hallucinations
• Consciousness level (quantitative aspect or arousal)
  awake – unarousable – dead

Question 3

Impairments of qualitative consciousness

Answer 3

• “Clouded awareness” (e.g., following alcohol consumption)
• Narrowing of one’s awareness (e.g., in phobia)
• Awareness shift (e.g., in psychosis)

Question 4

Impairments of quantitative consciousness

Answer 4

• Drowsiness – normal sleepiness
• Somnolence – abnormal sleepiness, but acoustically arousable
• Sopor – no spontaneous movements, reaction to pain stimuli adequate
• Coma – no reaction to visual, acoustic or pain stimuli

Question 5

Causes for becoming unconscious

Answer 5

• High intracranial pressure or direct affection to brain structures (e.g. trauma)
• Psychogenic/Psychiatric
• Neurological conditions (e.g. seizures)
• Medical interventions
• Physiological (e.g. sleep)

Question 6

Clinical assesment of consciousness

Answer 6

Inferences made from responses to
external stimuli which are observed at the time of the examination:
* Is the patient awake?
* Is the patient oriented in time and place?
* Does she/he react purposeful to the environment or to external
stimuli such as addressing patient, or pain stimuli? How is the
reaction?
* Does she/he fixate with the eyes?
* Does she/he show emotional reactions?

Question 7

Neurological examination of consciousness

Answer 7

• Mental status
• Brainstem reflexes, cranial nerve status
• Vital parameters, breathing patterns
• Sensorimotor examination, coordination/gait
• Vegetative responses

Question 8

Scales of consciousness

Answer 8

• Mini Mental State (MMS)
• Glasgow Coma Scale (GCS)
• Coma Recovery Scale-Revised (CRSR)
• Sensory Modality Assessment and Rehabilitation Technique (SMART)
• Disorders Of Consciousness Scale (DOCS)

Question 9

Coma

Answer 9

• Absence of arousal and awareness (→ unconsciousness)
• State of “unresponsiveness” to external stimulation
• Persistence for at least 1 hour
• Electroencephalographic (EEG) activity detectable

Question 10

Brain death

Answer 10

• Final breakdown of all brain functions: no spontaneous breathing, no brain stem reflexes
• No clinical evidence of brain function as evaluated by two independent neurologists at multiple times
• No perfusion in brain tissue with perfusion detecting ultrasound scan
• Flat EEG

Question 11

Locked-in’ syndrome

Answer 11

• Almost complete motor de-efferentiation leading to quadriparesis and anarthria (mostly caused by stroke in the ventral pons)
• Preservation of cognitive, sensory and emotional functions
• Fully conscious and awake state
• Inability to naturally communicate

Question 12

Types of Locked-in syndrome

Answer 12

• Incomplete LIS, in which voluntary movements are still possible to a small extent
• Classical LIS, in which the whole body is immobile except for eye blinking and small vertical eye movements
• Complete (or total) LIS, in which patients are completely unable to voluntarily move any part of their body