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EEG Flashcards to help with registration exam

In 1875, who recorded electrical activity in an animals brain? Richard Canton
Richard Canton discovered two important realizations when recording the animal brain. 1. The existence of electrical currents. 2. First description "external surface of gray matter usually is positive."
In 1890, who found oscillatory potentials when recording between two electrodes? Adolf Beck
When was the eletrokephalogram now the electroencephalogram created? 1929
When and who discovered 3Hz Spike and Wave? Gibs et Al in 1935
Herbert Jasper discovered this important abnormality in 1936? Focal spikes in focal seizure.
In 1936, Grey Walter found what? Focal slowing in correspondence with a tumor.
Evoked potential electrical response to an external stimulus (visual, auditory, sensory)
Who was the first to use "photogenic summation", a technique by superimposing a number of photographed wave forms in response to repeated external stimuli? VEP, AEP, SSEP George Dawson
Jewett discovered FFP, which is? Far field potential ;small amplitude activity in response to auditory stimulation (distance.) Also called Jewett Bump, now called BAEP, a brainstem auditory evoked potential
CT Scans or computerized tomography is used to detect and localize what? Brain lesions
EEG and CT scans work together to localize lesions using what? Topographic mapping
Topographic mapping is? Done by measuring amplitude values of given waves and interpolating values where there are no electrodes from the known values of neighboring electrodes.
What are still better at detecting anatomical and functional brain disturbances? CT and MRI
What factors work against the EEG for it to accurately map? 1. Recording on the scalp greatly attenuated and distorted by the CSF, skull, and scalp. 2. Scalp recording may not only record cortical activity, but also subcortical activity.
What is dipole localizing? Estimating an electrical source with inverse calculation by measuring the potential field (dipole field disturbance), which spreads between the electrical source and the pickup electrode via volume condition. (finding the source of potential generator)
What is Principle (1), that goes along with dipole localization? Current flows positive to negative source, creating positive and negative fields on the electro-conductive medium.
Magnetoencephalography Magnetic fields that aren't affected by tissues to over come attenuated and distorted electrical currents from a scalp electrodes.
MEG detects magnetic fields created by current flow over the cortex.
All labs have a minimum of two members, who are they? 1. EEG tech 2. Electroencphalographer (physician)
Electrode junction box does what? EEG signal is amplified and filtered, restricting the band pass of the amplified signal. This eliminates external interference.
The computer is used for? Digitizing data sent. Data from each channel are stored with signal reference format and also reformatting to appropriate parameters to display.
List tools used in correct order from patient to visually seeing the EEG on a monitor? 1. Input cable 2. Electrode junction box or head box 3. USB Communication to amplifier 4. Computer 5. Video monitor
What are electrode disks made of? 1. silver- silver chloride (most common) 2. platinum 3. gold
How large are disk electrode usually? 4-10mm
What are placed in the cups of the electrodes? Conductive paste/jelly.
Notch filter is? AC filter, alternating current flow
What form an impedance "resistance"? Compacitors and resistors
What is the preferred impedances and why? 5kΩ or less no more than 10kΩ. Unequal imbalances hindering recording quality. High impedances create artifact with movement.
What is an "electrode pop"? Can mimic an abnormality, caused by drying or unstable electrode surface contact with the skin. Can even occur with a low impedance.
If the integrity of the silver- silver chloride electrode is compromised, what do you do? First use a salt solution (gel) and a blunt tip into the electrode. Second removing the electrode and rescrubbing. Their replace the entire electrode.
What is the subdermal needle electrode? These are inserted just beneath the skin. Disposable, mostly used for intraoperative monitoring.
What is nasopharyngeal electrode? PG1 and PG2. Noninvasivley record activity from inferior and messiah temporal lobe as well as orbitofrontal activity.
T1 AND T2 Are placed over the cheeks to find messiah temporal abnormalities.
Who was the First person to describe electrical activity in the human brain? Hans Berger
All of the following tests reflect brain function except :EEG, PETScan, SPECT, CT CT
Common mode rejection ratio CMRR is closely related to a ? Balanced amplifier
Low frequency filter can be used to? 1. accentuating lower frequencies 2. reducing lower frequencies 3. reducing sweat artifact
To visually enhance subtle slow waves? 1.Lower lo frequency filter 2. Lower high pass filter 3. use slow sweep (paper) speed
The time it takes calibration to decay 63% from full scale is? Time constant
Which type of montage most closely gives true amplitude at any electrode? non-cephalic reference
Bipolar montage will do what? 1.Combine serial pairs of electrodes into a chain 2. in a chain of electrodes, Input 2 of one channel of is the same electrode as Input 1 of the next. 3. In the U.S. the left scalp electrodes appear first and then the right scapl electrodes.
What type of montage uses many electrodes as a reference? Average reference
What does Biocalibration demonstrate The calibration demonstrated the integrity of the system from patient to instrument
Average reference best used to? localize focal activity
Laplacian montage is used for? topographic mapping
Frequency equation F(Hz)= 1,000ms/duration of wave (ms)
Time constant equation TC=R (resistance) x C (capacitance)
Changing filters effects what? amplitude and phase of waves
Low frequency filter (LFF) or (high-pass filter) can enhance or eliminate slower (lower) frequency without effecting higher frequency (faster frequency)
Referential montage monopolar; utilizes one scalp electrode and 1 reference electrode in each channel. most common A1 and A2, comparing right and left activity
Positive and negative values will derive an average near zero with this montage? Average reference
Bipolar montage serial pairs of electrodes connected in longitudinal, transverse, or circumferential lines. Defining the location of maximum potential.
Electrode with maximum voltage within a series is? Phase reversal
A weighted average derived from adjacent (neighboring) electrodes found by using what montage? Laplacian
Double banana or _______ views symmetry between what? Longitudinal montage views symmetry between right and left hemispheres
What montage runs equally from left to right? Why is this useful? Transverse; this is useful by determining which area of activity has most dominance.
How is the transverse montage not helpful? Less helpful determining potential gradient of anterior-posterior activities are symmetric.
What do you see with Hat- band? usually occipital acticity
When will you use Triangular montage? When long inter-electrode distances are useful to delineate small potentials which may not be seen because of cancellation of neighboring electrodes.
Calibrate why? To make sure all channels are functioning equally.
What kind of wave does calibration signal and to what current? A square wave is calibrated to signal a direct current (DC)
Current (I) What is he unit of measure? Ampere
Resistance (R) What is the unit of measurement? Ohm
Capacitance What is the unit of measurement? Farad
Inductance What is the unit of measurement? Henry
Ohm's Law formula can be interchanged, but what are the three main components for these interchangeable formula? Why are they interchangeable? Current (I), resistance (R) and voltage (E), this is because they are interrelated in a circuit.
What formulas can you use to find power and why? P=E X I P=I²R (since E=I X R) P=E²/R (since I=E/R)
When two capacitors are placed parallel to one another what do you do to get a total measurement? You add them if they are parallel and keep the same units of measurement.
What is equivalent resistance of two equal resistors that are parallel? Half of the two equal resistors, but as individual resistors. one is 10Ω the other is 10Ω so 5Ω is the equivalent resistance
How much current would flow through the resistors at the output when 100 volts is applied? 1ampere
The decay time constant for low frequency filter in terms of R and C? R X C
The (decay) time constant of a low frequency filter can be measured by calibrating and measuring ? when the output drops 37% of the initial height
At what frequency dose the out put of a low frequency filter =70% of the input? When frequency =1/(2πRC)
Why is the patient more susceptible to electrical shocking? Well applied electrodes bypass the protective, dry outer layer of skin.
What is it about electrical shock that makes it lethal? The heart will go into fibrillation and not return, even when the current/voltage source is removed.
On a chord to power the EEG we use three prong chords and receptacles, why? The U shaped prongs are our ground. This is to stop from hocking the patient.
What does EMF mean and what does it do? Electromotive force; this causes current to flow through a wire.
Current is? rate of electron flow
Resistance does what to the current? properly limits the current
How is flow related to resistance? Flow is inversely related to resistance; 1/ resistance or pressure/ resistance
Series resistors are? Combined resistances in a series and will always be greater then any individual resistances (add them).
Parallel resistors formula Rparallel = 1/(1/R1)+(1/R2)...
Capacitors series formula Cseries = 1/(1/C1)+(1/C2)...
Inductance is ? Ratio of magnetic flux to the current in a circuit; are combined like resistors in series and parallel
Hydraulic analogy of inductance is? Inertia= fluid at rest stays at rest; fluid in motion stays in motion
what is the ground loop ? Loop of wire around a room, by generating a magnetic field and a current in a loop
Can a ground loop cause interference? Resistance is low and max current flow can generate artifact on ground and flow through patient.
Impedance capacitor formula ZC= 1/2πCF
Formula to calculate attenuation for HFF Tangent⁻¹1=45°
Most commercially digitized EEG systems can hold how many steps? 4096
Horizontal (time) resolution is determined by? Dwell time
What is the amount o time between two sampling points? Dwell time
A long Dwell time will cause? Increased resolution and smoothed out waveform.
What is the Nyquist theorem? For digitized data, fastest signal can be recorded is frequency that is half the sampling rate of the digitizer.
Amplitude distortion that appear as recorded frequencies near the Nyquist frequency are called? Aliasing
How do you reduce Aliasing? analog filtering before ADC (the ability to take analog and digital converter or digitizer, transforming analog measurements into numbers)
What matter is closest to the brain? Pia matter
Which membrane covering is closest to the skull? Dura matter
CSF fluid fills the area between? The arachnoid and the pia
The cerebral cortex, basal ganglia, and thalamus are all part of gray matter
Name the 4 lobes of the brain Frontal, parietal, occipital, temporal
The lobes of the brain are separated by? Sulci
Frontals main function? Motor function
Temporal main function? Hearing
Parietal main function? Sensation
Occipital vision
Which two lobes are separated by the Rolandic Fissure? Frontal/Parietal
Which lobes are separated by the Sylvian (Lateral ) fissure? Temporal, frontal, parietal
Along the motor cortex, which area is represented closest to midline? Leg
Language function is located in the ________ hemisphere? Dominant
Most people have speech function in the? Left hemisphere
The motor cortex of speech, locate in the inferior part of the frontal gyrus, is called? Broca's area; able to understand the spoken words, but unable to speak if area is damaged.
Motor aphasia able to understand, but unable to speak
If a patient can feel an object, but is unable to identify the object? Sensory agnosia
When the patient can see and object, but unable to identify it? Visual agnosia
Which area of the CSF contains nuclei of the cranial nerves III to XII? Brain Stem
Which fiber tract carries ascending sensory fibers for proprioception and vibration senses? Medial lemniscus
Most of the descending fibers cross to the appropriate site at? Pyramids
Which part of the CNS coordinates precise voluntary movements? Cerebellum
Which of the following are not a sign of cerebellar dysfunction? Ataxia, dysarthria, aphasia, dysmetria Aphasia; a patient with aphasia often has accompanying right hemiparesis (affecting the left side of the brain).
Name what protects the Spinal chord? Vertebrae, dura matter, CSF
The anterior and posterior spinal chord nerve root carries what kind of information? Motor and sensory respectively
The afferent and efferent pathways are represented by? Sensory and motor systems respectively
Which is not one of the main arteries directly supplying blood to the brain? Anterior cerebral, posterior cerebral, middle cerebral, basilar Basilar artery
Describe the Circle of Willis An interconnecting group of arteries connecting the left and right hemisphere.
Which artery supplies the largest portion of blood to the Lateral hemisphere? Middle cerebral
The Circle of Willis connects all of the following arteries except? Anterior communication, anterior cerebral, Posterior cerebral, basilar Basilar
CSF is manufactured within the? Ventricles
Which is not one of the major ventricles of the brain? Second, lateral, third, fourth? Lateral
The foramen of Monro connects which ventricles? Lateral and third
What is the nerve cell body called? Soma
Which type of nerve fiber transmits signals faster? Myelinated
The resting membrane potential INSIDE THE CELL IS? -70mV
EPSP and IPSP are both? Excitatory and inhibitory post-synaptic potential, respectively EPSP causes depolarization IPSI causes hyperpolarization
What maintains the chemicals inside and outside the cell? Sodium - potassium pump
EEG is primarily derived from integration of ? EPSP and IPSP
Specific and non specific projection systems arise from the? thalamic system
The patient with damage in the left occipital region likely has ? right visual defect
The patient having lesion in the post- central gyrus will have? right semi-sensory loss
The patient with a lesion in the left superior temporal gyrus shows? Sensory aphasia
Olfactory I What type? where is it located? What does it transmit? sensory Olfactory bulb Olfactory receptors for smell
Optic II Type? Location? What does it transmit? Sensory Thalamus Retina for senses of sight
Oculomotor III Type? Location? What does it transmit? Motor Midbrain Eye muscles (including eyelids and lens); pupil (parasympathetic division)
Trochlear IV Type? Location? What does it transmit? Motor Midbrain Eye muscles
Trigeminal V Type? Location? What does it transmit? Mixed (sensory and motor) Pons Teeth, eyes, skin, and tongue
Abducers VI Type? Location? What does it transmit? Motor Pons Eye muscles
Facial VII Type? Location? What does it transmit? Mixed (sensory and motor) PonsTaste buds of anterior tongue
Vestibulocochlear VIII Type? Location? What does it transmit? Sensory Ponns Inner ear for sense of balance and hearing
Glossopharyngeal IX Type? Location? What does it transmit? Mixed (sensory and motor) Medulla oblongata Pharynx
Vagus X Type? Location? What does it transmit? Sensory- Medulla oblongata - Internal organs Motor - Medulla oblongata- internal organs (parasympathetic division)
Spinal accessory XI Type? Location? What does it transmit? Motor Medulla oblongata Neck and back muscles
Hypoglossal XII Type? Location? What does it transmit? Motor Medulla oblongata Tongue muscles
Bell's Palsy, What is it and what can cause this? Sudden weakness to one side of the face; a lesion on cranial nerve VII (Facial)
Cerebellum Location? What does it do? Located in posterior cranial fossa; controls voluntary movement
Ataxia disturbance of voluntary movement, damage to hemisphere
Truncal ataxia Lesion on midline of cerebellum (vermis)
Dysmetria failure to coordinate movements and tongue
Brainstem Controls elementary life sustaining functions
Cerebrum Largest, 2 hemispheres connected by corpus callosum (white matter)
gyri multiple fold in brain
Sucli major folds of fissures
Frontal and parietal separated by? Central sulcus or rolandic fissure
Frontal, parietal, and temporal separated by? lateral sulcus or sylvan fissure
Parietal and occipital separated by? parieto- occipital fissure
Pre-central gyrus- central sulcus primary motor cortex
Wernicke's area can speak, but not able to understand spoken language
Sensory agnosia feel object in hand, but cannot identify it
Visual agnosia object is seen, but not recognized
Alexia unable to read
Agraphia unable to write
Astereognosis unable to appreciate texture, size and form by touch due to lesion on superior parietal lobe
Apraxia unable to perform purposeful and learned act i.e. driving due to lesion of various association cortex in dominant hemisphere
Amnesia loss of memory, lesion in hippocampus
What supplies blood to the brain? Internal carotid artery, Vertebral artery, Circle of Willis
6 major sinuses that collect venous drainage? Superior sagittal, inferior sagittal, straight, occipital, transverse, sigmoid sinus
The lateral rectus for eye movement is controlled by? Cranial nerve Abducers VI
Lesion at angular gyrus causes? Agraphia
Ansomia inability to smell
Dysarthria Difficulty with speaking due to lesion at the cerebellum
The sensory fibers enter the spinal cord at which part? Posterior, while anterior is motor
The vertebral artery supplies blood flow to what structures? Cerebellum, brainstem, spinal cord
In the ventricular system there is CSF
The main blood supply to the spinal cord is? Basilar artery
What produces spinal fluid? Choroid plexus
The medulla oblongata controls this important function? respiration
An occlusion of the left anterior cerebral artery likely results in Right lower extremity weakness
Thrombosis of the right middle cerebral artery likely causes? Left arm and face paralysis
Proprioceptive sensation join and vibration senses
The slow conducting sensory fibers run through which spinal cord column? Lateral
Brown- èSèquard syndrome consists of? Loss of proprioceptive sense and motor paralysis on the side of lesion, and loss of pain/temperature sense on the opposite side.
Subdural hematoma build up of blood on the surface of the brain and in-between the protective minengies
At the resisting state of a neuron the sodium ion if high outside and the potassium ion is high inside the cell
Node of Ranvier allows an impulse to travel faster; is a gap between two myelinated sheaths
An action potential results from the sudden entrance of the sodium ion into the cell
The fastest conduction velocity of a nerve is about 70-120m/sec; the fastest conducting fibers are large myelinated fibers
An example of the efferent system (motor) is Corticospinal tract
The slowest conduction velocity of the nerve is 0.5-2m/sec
Salutatory conduction is made possible by insulated material of myelin sheath
The nerve fiber with the fastest conduction velocity is Alpha
CVA affecting the left posterior cerebral artery may cause right homonymous hemianopsia
An example of afferent (Sensory) system is spinothalamic tract
Influx of sodium into the cell causes depolarization; which is excitatory depolarization of membrane potential
Hyperpolarization of membrane potential is the inhibitory state
Action potentials releases neurotransmitters in the Synaptic cleft
Action potentials has a _______ characteristics and occurs when membrane potential reaches above the ______. all or none threshold
PSP has _________ characteristics and occurs at the ______. graded post-synapse
Pons regulates sleep
Reticular activation system relates to wakefulness
When EEG activity is recorded from the scalp and from the cortex is compared: cortical recorded EEG has a much higher amplitude and a greater fast activity than scalp recorded EEG
PDR of a 3 year old? 7-8Hz
Which groups has the highest amplitude of alpha? children
Typical adult amplitude is in what range? <100uV
Duration of a spike? < 70msec
An alpha frequency activity with a pointed negative polarity at he central electrodes is? Mu rhythm, wicket spikes, rhythme en arceau
FIRDA monomorphic; metabolic encephalopathy
A transient is a normal varient
Temporal factors relate to timing
Synchrony is when two sides have equal timing
Increased delta activity in response arousal stimulus in comatose patient is paradoxical arousal response
which of the following is not a synonym for wicket rhythm? Arch rhythm, comb rhythm, rhyme en arceau, wicket spikes wicket spikes
Polymorphic slow waves are often seen in focal pathology
OIRDA absence seizures
The acceptable amplitude asymmetry of alpha to be considered normal is <50%
Sleep spindles may not be visible on one hemisphere due to? craniotomy
Beta activity can be enhanced by sedatives, hypnotics, anxiolytic drugs
The sleep stage with the most prevalent delta in a normal EEG stage IV (N3) sleep
Sleep spindles are in what stage of sleep? stage II (N2) as well as Vertex, k- complexes
What is the activity called when a 3 year old is just getting drowsy and shows high amplitude 3-5Hz bursts of activity? Hypnagognic hypersynchrony
REM sleep has what characteristics? Saw tooth waves, decreased muscle tone, increased muscle twitches.
Asynchronous sleep spindles can be considered abnormal after age of? 2 years
REM sleep ocuppies what percentage in neonates? 50%
lambda waves appear while scanning , reading, watching tv
Stage 1 sleep has what characteristics? Posts, Vertex, drifting eye movements
K-complex has highest amplitude at the frontal region
Stage II sleep in a 3 year old should have what characteristics? Synchronous spindles, POSTS, Mu-shaped sleep spindles, large occipital delta slow waves
Sleep spindles are not expected in babies younger than? 3 months
Asynchronous sleep spindles are characteristic for babies younger than 1 year
To be considered abnormal, an amplitude asymmetry of alpha rhythm should be greater than 50%
Which disease often shows an unusually low voltage PDR? Huntington's disease
Unilateral or focal depression of beta is a reliable indicator of focal cortical dysfunction
Focal arrhythmic delta activity is a reliable indicator of? focal white matter dysfunction
Breach rhythm typically consists of Alpha and beta
A family history of epilepsy is often positive in patients who have? What does this suggest? photoparoxysmal response; suggesting primary generalized seizure
Hyperventilation causes hypocapnia; delta-theta activity is normal no matter how prominent the slow waves are.
The most effective frequency to elicit a photoparxsymal response is? 15-20Hz
All of the following increase the chance of detecting IEDs in patients with partial complex epilepsy of temporal lobe origin except: Photic, HV, Sleep, Sleep deprivation photic
IEDs are activated most commonly in what stage of sleep? Stage I/II
An example of a reflex epilepsy? Musicogenic seizures are triggered by music
what percentage chance will you find IEDs during the first adult EEG? What about children? 30-50%; there are higher chances in children
Which type os seizure is the most common? Complex partial
Hypsarrhythmia pattern on EEG is associated with which seizure? What is it not associated with? Infantile spasms (West syndrome); Impulsive petit mal
Landau- Kellner syndrome is associated with all of the following, but? Aphasia, tends to normalize in time, electrographice status in sleep, seizures triggered by fever seizures triggered by fever (uncomplicated febrile seizure in children usually shows normal EEG)
Subacute sclerosing panencephalitis EEG diffuse slowing periodic pattern repeating at 4 to 15 seconds and sometimes associated with myoclonus
A seizure characterized by a sudden loss of muscle tone is? atonic
In which seizure type does epileptiform activity tend to decrease in sleep and increase shortly after wakening? JME; rhythmic poly spike-wave bursts
Landau- Kleffiner syndrome Dysphasia- language disorder cannot understand spoken word
Peak age of childhood epilepsy with occipital paroxysm is? 3-6 years
Focal seizures with symptoms of "tingling" sensations in the face likely originate from? inferior post- central gyrus
Created by: AlexiaMauzy