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EEG REG TECH
EEG Flashcards to help with registration exam
| Question | Answer |
|---|---|
| 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. |
| Describe voltage? | ELECTRICAL FORCE THAT MOVES ELECTRONS THROUGH WIRES AND DEVICES. |
| 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 |
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