What is encompassed in Consciousness?
Perception of sensation
Voluntary initiation and control of movement
Capabilities associated with higher mental processing
- Is superimposed on other types of neural activity: totally interconnected
Define Clinical Consciousness
a continuum that grades levels of behavior
awak, alert & oriented – Disoriented – Lethargic – Obtunded – Stuporous – Comatose
What is LOC?
Loss of Consciousness
(any loss of consciousness reported as LOC)
Describe Brain Waves
- Normal brain function involves continuous electrical activity
- Patterns of neuronal electrical activity recorded are called brain waves
- Each person’s brain waves are unique
- Change with age, sensory stimuli, brain disease, and chemical states of the body
What are the four types of Brain Waves?
Alpha
Beta
Theta
Delta
Describe an Alpha brain wave
regular & rhythmic, low-amplitude, slow & synchronous; indicate an “idling” brain
Describe a Beta brain wave
rhythmic, more irregular waves occurring during the awake & mentally alert state
Describe a Theta brain wave
more irregular than alpha waves; common in children but abnormal in adults
Describe a Delta brain wave
high-amplitude waves seen in deep sleep & when RAS input is reduced
How is brain wave activity recorded?
through an Electroencephalogram (EEG)
What is the unit of measure for brain wave frequency?
Hertz (Hz)
Clinical Correlates for Higher Mental Functions
describe EEGs
EEGs are used to diagnose and localize brain lesions, tumors, infarcts, infections, abscesses, and epileptic lesions
- a flat EEG (no electrical activity) is clinical evidence of death
Clinical Correlates for Higher Mental Functions
What is Epilepsy?
- Regions of abnormal electrical discharge with physical manifestations
- is not associated with, nor does it cause, intellectual impairments
- often preceded by a sensory hallucination (taste, smell, flash of light); known as an aura
Describe a Tonic-Clonic seizure (grand mal)
- Focal point in the motor cortex
- patient will lose consciousness, fall stiffly, and have uncontrollable jerking, loss of bowel and bladder control & severe biting of the tongue
- bones are often broken due to intensity of convulsions
Describe an Absence seizure (petit mal)
mild seizures seen in young children where the expression goes blank for a few seconds with brief LOC
Describe Epilepsy Treatments
- Can be controlled with anti-convulsive drugs
- Valproic acid, a non-sedating drug, enhances GABA (inhibitory) and is a drug of choice
- Vagus nerve stimulators can be implanted under the skin of the chest or near medulla and can keep electrical activity of the brain from becoming chaotic
- UW researches developed electrode implants that pinpoint locus of seizure (thus focal point of seizure can be removed w/out damaging other areas)
How do they treat Intractable Seizures?
severing of the Corpus Callosum is used as a last resort.
Associate problems: R/L hemisphere information transfer significantly minimized; Speech-Language deficites, alien hand syndrome
