Nyquist Theory
The specification of the minimum sampling rate used, in relation to the highest frequency signal recorded
The sample rate must be twice
... [Show More] that of the highest frequency to be recorded.
For LFF, the corresponding time constants for LFF cutout freq. of 3 hz would be __
.05 seconds
The most prominent clinical feature of Dilantin toxicity?
Ataxia
Ataxia
lack of muscle coordination
Agnosia
the inability to recognize familiar objects.
Apraxia
inability to perform particular purposive actions, as a result of brain damage.
Diplopia
double vision
Foramen of Monro
connects lateral ventricles to third ventricle
Foramen magnum
the brain connects to the spinal cord.
Foramen of Luschka
lateral aperture that connects fourth ventricle to subarachnoid space
damage to the cerebral cortex
motor weakness, paralysis, loss of sensation, impaired ability to understand and process language
Damage to Wernicke's area
receptive aphasia - inability to understand words
Damage to Broca's area
expressive aphasia - inability to produce language
Dysarthria
slurred speech
Scotoma
blind spot in vision
Ohms law
the current in a circuit equals the voltage difference divided by the resistance
V=IR
Coulomb's Law
electric force between charged objects depends on the distance between the objects and the magnitude of the charges.
Gelastic Seizures
hypothalamic hamartoma
Brief periods of laughter
Symptoms of Hemorrhagic Stroke
Exploding headache, decreased level of consciousness, numbness/weakness on one side, vomitting, stiff neck (nochal rigidity - which is also associated with Meningitis)
Symptoms of ischemic stroke
Numbness of face, arm, leg (especially on one side). Confusion, speech, seeing double or blurry, visual disturbances, trouble walking, perceptual problems
symptoms of subdural hematoma
headache, lethargy, may show focal signs, may be asymptomatic
Symptoms of subarachnoid hemorrhage
Intolerance to light
Neck stiffness/pain
empyema
pus in the pleural cavity
Depolarization
The process during the action potential when sodium is rushing into the cell causing the interior to become more positive.
Repolarization
Return of the cell to resting state, caused by reentry of potassium into the cell while sodium exits the cell.
Rolandic fissure (central sulcus)
fissure that divides frontal lobe from parietal lobe
Heschl's gyrus
A superior temporal lobe gyrus that is located in the lateral fissure of each hemisphere; it is the location of most of the primary auditory cortex
Anoxia
No oxygen
Hypoxia
Reduced oxygen
PLEDS
Periodic lateralized epileptiform discharges. These are sharp complexes that are non-reactive to stimulation and are more pronounced with drowsiness. Tend to occur with cerebral infarction or severe damage.
nephrotic syndrome
group of clinical signs and symptoms caused by excessive protein loss in urine
Uncus
on medial surface of temporal lobe (olfactory area)
trace' discontinue
less than 30 weeks conceptual age
Involves bursts of medium to high amp, mixed frequency waves that are random and paroxysmal
posterior head regions
Trace Alternant
-less discontinous than trace' dicontinue . . periods between bursts are of shorter duration
-may be present until 1 month of age
-quiet sleep
Gyrus
A convoluted ridge between anatomical grooves.
Subacute sclerosing panencephalitis (SSPE)
Measles
By one year of age, the dominant background rhythm should be ___
5 to 6 hz
Hertz of Mu
8-10hz
A 7 year old male presents with a 6 month history of spells involving numbness and tingling of his tongue. He remains concious the entire time and occasionally drools. What do you expect to see on the EEG?
Centro-Temporal spikes
GPEDS/GPDS are seen with what disease?
Creuetzfeldt-Jakob Disease
Delta brushes are seen in ___
A neonate in quiet sleep
Normal HV response in children
High voltage bilateral delta activity maximal in the posterior regions
If the EEG of a term newborn with asphyxia shows nonreactivity and periods of severe attenuation with bursts of mixed activity every 10 to 20 seconds, what is most likely?
Severe cortical injury due to hypoxic-ischemic encephalopathy
Laplacian montage
Source reference derivation
What is frequency measured in and what is it influenced by
Hertz and sampling rate
What happens when a 60 cycle sine wave is sampled at 100 hertz?
Aliasing
Aliasing
misperception of a grating due to undersampling
Doubling the inter-electrode distances will have what effect on the waveforms
increase amplitude
What encephalopathic EEG pattern is most commonly associated with children?
OIRDA
Hypocapnia
insufficient carbon dioxide (hyperventilation)
Hyperglycemia
excessive sugar in the blood
Hypoglycemia
abnormally low level of sugar in the blood
Anterior cerebral artery stroke
contralateral motor and or sensory loss lower limbs
Seizure activity in which antaomical region may produce strong deja vu and chewing automatisms?
Temporal
Hemianopia
blindness over half the field of vision
Aphasia
inability to speak
Bilateral anterior beta activity is most likely to occur with what medication
Diazepam
Alpha rhythm polarity
Negative
Brain abcess would produce what eeg pattern
Focal polymorphic delta activity
Trace Discontinu is expected until what age
Up to 34 wks
Trace alternant age
36 weeks conceptual age or older which can persist up to 3-4 weeks after birth in full-term neonates
Frontal sharp transients neonate age
34-35 wks, persist through term
Age in which change EEG from stimuli occurs
33-34 wks CA
Clear EEG differences between wake and sleep occur at what age?
36-37wks CA
Photomyogenic Response
EMG artifacts time locked with the flash frequency of photic stimulation [Show Less]