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AAET NCV/EMG

Terms in this set (260)

What describes an atom in which the total number of electrons is not equal to the total number of protons, giving the atom a net positive or negative electrical charge?
Ion
What is the negatively charged particle in an atom?
Electron
What has neutral particles, along with protons, and is found in the nucleus of an atom?
Neutrons
Which particles of an atom are positively charged?
Protons
What makes up the elements found in all matter?
Atoms
What is the voltage inside the nerve cell membrane in a resting membrane potential?
-90 to -70mV
What is the major ion outside a cell membrane?
Sodium
What is the major ion inside a cell membrane?
Potassium
What is the physiological term when depolarization occurs it causes a muscle and/or nerve fiber to either respond to a stimulus completely if it reaches threshold or no response if the depolarization is insufficient to reach threshold?
All Or None Response
What describes changing from a resting potential or polarized state to an excited state?
Depolarization
What causes the inside of the cell to be more positively charged relative to its resting state?
Depolarization
What describes when nerve cells are changed from an excited state back to a resting electrical potential or polarized state?
Repolarization
What causes the inside of the cell to be more negatively charged relative to its resting state?
Hyperpolarization
During the repolarization phase, sodium channels become inactivated and cannot be opened no matter how much depolarization occurs and no action potential can be generated no matter how strong the stimulus. What is this?
Absolute Refractory Period
In the later stages of repolarization, a brief increase in the permeability to potassium occurs and this results in hyperpolarizing the membrane and returning it slowly to its resting value during which time an increasing number of sodium channels can be opened. If you give a strong stimulus, it might be possible for another action potential to occur. This time is known as the?
Relative Refractory Period
Propagation of action potentials along myelinated axons from one Node of Ranvier to the next Node of Ranvier is called?
Saltatory Conduction
What is the name of the cells that are surrounding the axon to form the myelin sheath?
Schawnn Cells
What describes the periodic gaps in the insulating sheath (myelin) on the axon through which ion channels allow the flow of ions across the nerve membrane?
Nodes of Ranvier
The length between two nodes of Ranvier is called?
Internodal Length
Forcing sodium out of the cell and potassium in is the function of what?
Sodium-Potassium Pump
What can increase or decrease the conduction velocity of a nerve?
Diameter of the axon and degree of myelination
What types of fibers mediate pain, temperature, and autonomic function?
Unmyelinated Fibers
Nerve fiber bundles' having a common destination describes?
Fascicles
Each individual fascicle is surrounded by connective tissue called?
Perineurium
What is the connective tissue between individual axons called?
Endoneurium
What is the name of the outer supportive layer of connective tissue which surrounds the whole nerve and binds fascicles to each other?
Epineurium
What types of nerve fibers are myelinated?
Type- A fibers are myelinated fibers of somatic nerve that can innervate muscle or skin Type B- fibers are myelinated preganglionic fibers
Which type of nerve fiber is not fast and why?
Type C - because it is unmyelinated
Which nerve fiber is fast but not as fast as nerve fiber type A?
Type B -These fibers are myelinated but not as heavily as type A
What is the communication link between the central and peripheral nervous system?
Axons
What factors are important for fast conduction velocity?
Increased diameter and myelination of nerve fibers
Where is the dorsal root ganglion located?
Outside of the spinal cord
Where are motor neurons located?
Gray matter of anterior horn in the spinal cord
What is composed of sarcomeres and is responsible for muscle contraction?
Myofibrils
A structural subunit and that contains actin and myosin filaments?
Sarcomere
Which band contains only actin filaments?
I band
Which band contains only myosin filaments?
H band
Which band contains both actin and myosin filaments?
A band
Where are the Z bands located?
At the end of each sarcomere
What muscle fiber is called slow twitch muscle fiber?
Type I- slow twitch, or "red" muscle, is dense with capillaries and is rich in mitochondria and myoglobin, giving the muscle tissue its characteristic red color. Slow twitch fibers contract for long periods of time but with little force.
Which muscle fiber is called fast-twitch muscle fiber?
Type II a and Type II b Fast twitch fibers contract quickly and powerfully but fatigue very rapidly, sustaining only short, anaerobic bursts of activity before muscle contraction becomes painful. They contribute most to muscle strength and have greater potential for increase in mass. Type II b muscle fiber is white in color.
What filament is contained in the center of sarcomere?
Thick Myosin
Which filament is extending from either side of the Z line?
Thin Actin
What is released from the sarcoplasmic reticulum that aids in muscle contraction?
Calcium
What is the primary function of Sarcoplasmic Reticulum?
To store calcium ions (Ca 2 +)
Which two nerves originate directly from the cervical spinal nerve roots?
Dorsal Scapular and Long Thoracic Nerves
Motor and sensory roots at each spinal level unite distal to the dorsal root ganglia to become?
Mixed spinal nerve
What nerve roots contribute to the organization of the brachial plexus??
C5-T1
What are the five components of the brachial plexus?
Five roots C5-T1 Three trunks - upper, middle and lower Two divisions of each trunk Three cords Terminal nerves
What nerve roots make up the upper trunk?
Anterior rami ofC5-C6 roots
Which nerve root supplies the middle trunk?
C7
Which nerve roots make up the lower trunk?
C8-T1
What muscle is supplied by the long thoracic nerve?
Serratus Anterior
Which nerve is purely sensory and receives fibers from C8 - T1 roots?
Medial Antebrachial Nerve
Where is the location for Erb's point?
Triangle between the clavicle and the Sternocleidomastoid muscle
Lumbar Plexus is formed by what nerve roots?
L1-L4
The Lumbosacral Plexus is formed by which nerve roots?
L1-S4
The relationship between voltage, current and resistance in the equation E= I x R is known as?
Ohms Law
What is name of the law used to calculate the flow of electricity, E (Voltage) =I (current)?R (resistance)?
Ohms Law
What is an interconnection of components such that currents flow in one or more closed loops?
Circuit
What is a sample of a simple circuit?
I=I 1 +I 2 + I 3
What is an electrical device that provides specific resistances used to control current and voltage in electrical circuits?
Resistors
What reduces total resistance and is the sum of individual currents going through each resistor?
Resistors in Parallel Resistances act in parallel when they are arranged so that the total current in the current in the circuit is divided between the resistors and flows simultaneously through each of the parallel resistors.
The current flows in one path and is the same flowing through each resistor and can be directly added together to calculate a net resistance. This best describes?
Resistors in Series Resistances are acting in a series when all of the current in the circuit must flow through each of the resistors in sequence, one after another, end-to-end.
The process of generating a binary number proportional to the value of the analog input voltage. This best describes?
Analog to Digital Conversion (convert from Oscilloscope to digital computer)
There are lines or dots on the screen that represent divisions and correspond with the current sensitivity and sweep speed (timebase). The vertical divisions (top to bottom) represent -amplitude-and we refer to this as?
Vertical Resolution
There are lines or dots on the screen that represent divisions and correspond with the current sensitivity and sweep speed (timebase). The horizontal divisions (left to right) represent -latency or time- and we refer to this as?
Horizontal Resolution
The computer rewrites the analog line into a series of dots from which the line is recreated. This is called analog to digital conversion and these dots are called?
Data Points
n NCS, what describes the summation of the traces by the total number of traces collected in an effore to eliminate background noise?
Averaging
What describes the effect of passing some bands of frequencies while attenuating others?
Filtering Effects Filters have two main functions. First is to filter unwanted noise because noise can affect the baseline, making it difficult to determine the amplitude and onset latency marking of a waveform. Filters also help in the resolution of a waveform. The shape of a waveform changes when the filter settings are changed. A filter can limit or allow only the desired signals to go into the amplifier.
Varied fast and slow fibers cancel one another as one phase of the slow fibers reach the recording electrode, as the trailing phase of the fastest fibers pass the same recording electrode causing an apparent loss of amplitude.
Phase Cancellation In phase cancellation, the positive peaks of some axons may become superimposed on the negative peaks of others. Phase cancellation is much more pronounced in sensory rather than motor nerves causing an apparent loss of amplitude.
The hardware component used to increase the size of the small physiologic signal.
Amplifier The amplifier increases the magnitude of the signals, typically in the microvolt to millivolt ranges
What describes the parameters of 2-10 Hz (motor) and 20-30 Hz (sensory) and eliminates or attenuates (reduces) unwanted slow frequencies?
Low Frequency Filters
What describes the parameters of 5- 20 kHz (motor) and 2-3 kHz (sensory) and eliminates or attenuates (reduces) unwanted fast frequencies?
High Frequency Filters
What describes the horizontal measurement of time displayed on the screen?
Sweep Speed/Time Base
What describes the vertical measurement of amplitude of the waveform on the screen?
Sensitivity/Gain
Where should the vertical cursors be placed when measuring a sensory nerve action potential?
Onset and Peak of waveform
What type of stimulator delivers an adjustable current through the simulating electrodes independent of their impedance?
Constant current
What type of stimulators deliver an adjustable voltage across the stimulating electrodes independent of stimulus current?
Constant voltage
What describes the amount of electrical energy applied to produce a measurable response measured in volts or milliamps?
Intensity
What describes the length of time a stimulus is applied; measured in milliseconds and limited to a maximum of 1 msec?
Duration
The negative terminal of the stimulating electrode.
Cathode
The positive terminal of the stimulating electrode.
Anode
What describes the process when hyperpolarization occurs under the anode preventing the depolarization that occurs under the cathode from passing, thus causing a reduction in resting potential?
Anodal Block
What describes the process when stimulation spreads to nearby nerves resulting in erroneous results?
Volume Conduction
What describes an unwanted electrical signal that obscures the desired response recorded at the time the stimulus is applied?
Stimulus Artifact
What describes when an increase in stimulus no longer increases the size of the response?
Supramaximal Stimulation
A nerve root lesion proximal to the dorsal root ganglia, best describes?
Preganglionic
A nerve root lesion distal to the dorsal root ganglia, best describes?
Postganglionic
Which nerve root lesions have NCS findings that indicate absent motor responses and preserved sensory responses?
Preganglionic
Which nerve root lesions have NCS findings that indicate absent motor responses and absent sensory responses?
Postganglionic
What are the effects of a preganglionic lesion?
Most often, the lesion represents root avulsion from the spinal cord. The muscles supplied by the nerve root will atrophy. Surgical repair is impossible. Preganglionic injuries have limited spontaneous recovery.
The NCS term for lesions in a specific and definable location; usually found with short distance nerve conduction studies and are usually demyelinating lesions.
Focal
The NCS term when there is an amplitude and area difference in a response that is seen between the distal and proximal stimulation sites of a nerve. It is seen most often in demyelinating disorders when all technical factors have been eliminated.
Conduction Block
The term for peripheral neuropathy that essentially involves all nerves in a length-dependent fashion, to a relatively equal extent.
Diffuse Process
The term for peripheral neuropathy that involves one or multiple nerves in an asymmetric or patchy distribution.
Multifocal Disorder
What is the term for a disease or disorder affecting the myelin surrounding a peripheral nerve? The nerve conduction study will show conduction velocity slowing and/or conduction block.
Demyelination
What is the term for a loss of nerve fibers due to disease or injury?
Axonal Loss
What is a measurement of the time needed for the stimulus to travel from stimulation point to recording point (recording point may be the initial takeoff, the first positive peak or the negative peak)?
Latency
The measurement of the vertical size of the waveform.
Amplitude The representation of the total number of nerve fibers or sensory axons. Usually expressed as millivolts (mV) for MNC and microvolts (µV) for SNC.
A measurement of time in meters per second between two points. It is calculated from the fastest fibers as the difference in distance divided by difference in time.
Conduction Velocity
What is the term used to represent the duration and amplitude of a motor response? It is measured in mV and ms (for MNC, its most useful place) and helps differentiate between a conduction block and simple dispersion.
Area
The measurement from the first deviation to the baseline to the next crossing of that same baseline (negative phase).
Duration
The interval from the onset of a polarity change of a potential to its peak.
Rise Time
The values routinely used as references when performing nerve conduction studies. A lab either establishes its own values or uses another reputable lab's values.
Normal Values
Over longer conduction distances, what is the term for a long duration of the negative peak of a CMAP and SNAP?
Temporal Dispersion
A decrease in amplitude across a proximal nerve segment compared to the distal amplitude?
Amplitude Drop
What are the three most important technical issues encountered when performing infant or children nerve conductions studies?
1) Measurement 2) Electrode size 3) Stimulation intensity
What happens to the CMAP amplitude in pediatric nerve conduction studies?
It increases in direct proportion to age
The process of myelination is age dependent, beginning in utero. What is the approximate value of nerve conduction velocities in full-term infants?
Approximately half that of adult normal values: Accordingly nerve conduction velocities of 25 to 30 m/s are normal at birth
Conduction velocity rapidly increases after birth, reaching approximately 75% of adult normal values by age 1 year, and the adult range by _________>
3 to 5 years
At what age do sensory NCV reach mean adult values?
5 years of age
It is not uncommon to see bifid morphology on sensory nerve action potentials in infants and children between the ages 3 months and 4-6 years. Explain why?
Bifid morphology occurs due to some fibers having already been fully myelinated whereas others have not and trail behind. This is not unusual to see bifid SNAPS between the age of 3 months and 4-6 years. They are completely normal and as fibers of the second peak myelinate the second peak moves to the left and merges with the first peak, forming a larger sensory response, as typically seen in adults
Axonal degeneration that progresses from the place of injury along the axon (i.e. distal to a lesion)
Wallerian Degeneration
Nerve injury defined as, failure of nerve conduction in the absence of structural changes (primarily demyelinating as seen with slowing of the nerve conduction studies without axonal damage, meaning good prognosis)
Neurapraxia
Nerve injury defined as, nerve conduction slowing without complete block (axons and myelin disrupted, but supporting connective tissue is intact, allowing reinnervation of the axons)
Axonotmesis
Nerve injury defined as, partial or complete severance of a nerve, with disruption of the axon, its myelin sheath and connective tissue (mixed axonal and demyelinating when both conduction time and amplitude are affected)
Neurotmesis
A recording from any motor nerve, activated by antidromic stimulation that travels centrally to the spinal cord through interneurons and anterior horn cells, then orthodromically from the spinal cord to the muscle.
F Wave (origin)
Does the F-wave response travel centrally in the motor or sensory fibers?
Motor fibers
When performing an F-wave, should you use submaximal stimulation or supramaximal stimulation?
Supramaximal stimulation
In the upper extremity, when the median or ulnar nerves are stimulated at the wrist, the F response usually occurs at a latency of ______________msec?
25-32 msec.
Which has a longer latency, the F-wave or the M-wave?
F wave
What percentage of muscle fibers are represented by an F-wave?
1-5%
In order to avoid habituation of the F response, one should stimulate at a rate no faster than once every ___________ seconds?
2 seconds
A submaximal stimulus that arises from large Ia afferents of the muscle activates a monosynaptic reflex arc. These afferent impulses travel up the sensory fibers and enter the dorsal horn of the spinal cord. After entering the dorsal horn of the spinal cord, the Ia afferents synapse with the alpha motor neurons that activate that muscle and a CMAP is produced completing the reflex arc. This describes?
H Reflex (circuitry)
When performing an H reflex, should you use a submaximal or supramaximal stimulus?
Submaximal stimulus
Where is the proper stimulation point and orientation for the Tibial H-reflex?
Popliteal fossa with the cathode proximal
When comparing H-reflexes for side-to-side latency differences, a difference of more than ____________msec is considered clinically significant.
1.5 msec is considered clinically significant.
When performing an H-reflex, does the M wave or the H wave have the shorter latency?
M wave
When performing an H reflex, one should stimulate at a rate no faster than __________ Hz to avoid habituation.
0.5 Hz.
When an A wave (axon reflex) is seen during an F wave test, does it typically have a shorter or longer latency than the F wave?
Shorter latency
What can be done to try and eliminate the A waves?
Increase the stimulation to make sure it is at supramaximal stimulation.
The afferent limb of the blink reflex is mediated by the sensory fibers of which cranial nerve?
Cranial V
The efferent limb of the blink reflex is mediated by the motor fibers of which cranial nerve?
Cranial VII
The muscle(s) used to record the blink reflex. (Active electrode placement.
Bilateral Orbicularis Oculi muscles
Where is the reference electrode placed for the blink reflex?
Just Lateral to the lateral canthus bilaterally
When evaluating side-to-side comparisons of blink reflex studies, the difference between the R1 latencies should be ______________________?
<1.2 ms
Should the R1 response in a blink reflex study be present ipsilaterally or bilaterally?
Ipsilaterally
Should the R2 response in a blink reflex be present ipsilaterally or bilaterally when recording Orbicularis Oculi bilaterally?
Bilaterally
Describe the pathway that is thought to represent the R1 response?
The R1 response is thought to represent the disynaptic reflex pathway between the main sensory nucleus of cranial nerve V in the mid-pons and the ipsilateral facial nucleus in the lower pontine tegmentum.
Describe the pathway of the R2 responses in a blink reflex study.
The R2 responses are mediated by a multisynaptic pathway between the nucleus of the spinal tract of cranial nerve V in the ipsilateral pons and medulla and interneurons forming connections to the ipsilateral and contralateral facial nuclei.
A nerve action potential depolarizes the presynaptic junction, voltage-gated calcium channels are activated, allowing an influx of calcium. The infusion of calcium leads to release of release of ACH from the presynaptic terminal. ACH then diffuses across the synaptic cleft, and binds to ACH receptors on the postsynaptic muscle membrane. This results in local depolarization of the endplate potential. This describes?
Physiology of the neuromuscular junction.
Does Lambert-Eaton Myasthenic Syndrome affect the presynaptic or postsynaptic membranes?
Presynaptic
In Myasthenia Gravis, is the problem with the presynaptic or postsynaptic membrane?
Postsynaptic
Botulism blocks the presynaptic release of what neurotransmitter?
Acetylcholine (ACH)
Describe the technique for electrode stabilization for a repetitive stimulation study of the ulnar nerve
The fingers need to be strapped together to limit movement; the stimulator needs to be taped in position; the hand and forearm need to be strapped to an arm board to limit movement artifact.
Baseline and immediate postexercise or posttetanic 2 to 5 Hz nerve stimulation followed by stimulation at regular intervals of 30 s to 1 min, and continuing to 5 min. This describes?
Stimulation Parameters for Repetitive Nerve Stimulation:
A response occasionally seen in Repetitive Nerve Stimulation in which an increase of amplitude following identical stimulations. This describes?
Post activation facilitation
A response seen in Repetitive Nerve Stimulation in which, after exercise, a transient potentiation is followed by decreased excitability of the neuromuscular junction in 2 to 4 minutes after exercise.
Post activation exhaustion (posttetanic exhaustion)
A normal phenomenon caused by more synchronous firing of muscle fiber action potentials immediately following brief intense exercise.
Pseudofacilitation
In a repetitive nerve stimulation study, how much increment is considered abnormal?
Increments of more than 100% are often encountered in presynaptic Neuromuscular Junction disorders. Increments between 40 and 100% are best considered equivocal. What is meant by a percentage increment often is confusing; a 200% increment means that the potential increases by an extra 200% above baseline. For example: if the baseline CMAP is 1mV that increments to 3mV after 10 seconds of exercise, this is a 200% increment.
After performing the initial repetitive nerve study a decrement of greater than 10% is noted. How should you proceed with your repetitive nerve study?
Have the patient perform maximal voluntary exercise for 10 seconds. Then immediately repeat 3Hz repetitive nerve stimulation postexercise to demonstrate postexercise facilitation and repair of the decrement.
The nerve which arises from the C5-T1 roots and transverses all trunks and the lateral and medial cords of the brachial plexus
Median Nerve
When recording the Median motor nerve conduction study the active recording electrode should be placed over the belly of which muscle?
Abductor Pollicis Brevis
Which nerve supplies sensation to the thumb, index, middle and lateral side of the ring fingers?
Median sensory nerve
Recording electrodes are placed on the midportion of the proximal phalanx and reference on the midportion of the middle phalanx of the index finger for which nerve conduction study?
Median sensory nerve
Which nerve is a branch of the median nerve which originates several centimeters distal to the elbow and innervates several muscles in the forearm including the Pronator Quadratus, Flexor Pollicis Longus and the radial half of the Flexor Digitorum Profundus?
Anterior Interosseous nerve
Which nerve is being stimulated when recording electrodes are placed 2 cm proximal to the distal wrist crease between the Flexor Carpi Radialis and Palmaris Longus tendons and stimulation applied 8 cm distal to the active recording electrode between the second and third digit?
Palmar Cutaneous branch of the Median nerve
When recording the Ulnar Motor nerve conduction study the active recording electrode is placed on the belly of which muscle?
Abductor Digiti Minimi
Which nerve supplies sensation to the medial wrist to the fifth digit and the medial aspect of the fourth digit?
Ulnar sensory nerve
Which nerve branches from the ulnar nerve in the distal forearm receiving sensation from the dorsum of the hand, (half of the 4th digit and 5th digit)?
Dorsal Ulnar Cutaneous Nerve
What is a pure sensory nerve supplying sensation to the medial forearm, it rises from the C8-T1 nerve roots and lower trunk and comes directly off the medial cord of the brachial plexus?
Medial Antebrachial Cutaneous Nerve
Which nerve is a continuation of the posterior cord and has fibers from all roots (C5-T1) supplying the brachial plexus?
Radial nerve
When recording the Radial Motor nerve conduction study the active is placed over the belly of the _______and the reference is placed over the _______.
Extensor Digitorum Communis Muscle; Ulnar Styloid
What nerve is a continuation of the deep branch of the radial nerve that innervates the Extensor Digitorum Communis and Extensor Indicis Proprius muscles?
Posterior Interosseous Nerve
Which nerve splits off near the elbow and supplies sensation to the lateral portion of the dorsum of the hand?
Superficial Radial Nerve
What nerve arises from the C5-6-(7) nerve roots, upper trunk and lateral cord of the brachial plexus and supplies the bicep muscle which is the common recording location during MNC studies?
Musculocutaneous Nerve
Which nerve supplies sensation to the lateral portion of the forearm from the C5 and C6 nerve roots, upper trunk, and lateral cord?
Lateral Antebrachial Cutaneous Nerve
What is the sensory portion of Musculocutaneous nerve?
Lateral Antebrachial Cutaneous Nerve
For which nerve conduction study is the active recording electrode placed anterior and superior to the medial malleolus along the Tibialis Anterior tendon and the reference electrode is placed 3-4 cm distal along the course of the nerve.
Saphenous nerve
Which nerve is a pure sensory branch of the femoral nerve?
Saphenous nerve
This nerve innervates the Rectus Femoris muscle?
Femoral nerve
Which nerve is formed by L2-L4 nerve roots?
Femoral nerve
What nerve is pure sensory and receives sensation from the lateral thigh?
Lateral Femoral Cutaneous Nerve
The largest nerve in the body and innervates the deep muscles of the posterior thigh, including the Adductor Magnus, Semimembranous, Semitendinosus and the short and long heads of the Biceps Femoris.
Sciatic Nerve
The___________nerve bifurcates (splits) into the deep and superficial peroneal nerves.
Common Peroneal
Compression of this nerve results in dorsiflexion weakness (foot drop).
Deep Peroneal Nerve
Recording electrodes are placed over the Extensor Digitorum Brevis and reference at the base of the 5th metatarsal for which nerve?
Deep Peroneal Nerve
The active electrode is placed between the Tibialis Anterior tendon and Lateral Malleolus and the reference is 3-4 cm distal, for the recording of which nerve?
Superficial Peroneal Nerve
What nerve is the largest branch of the sciatic nerve formed from L4-S3 nerve roots, with Abductor Digiti Quinti Pedis and Abductor Hallucis as common muscles to record from when doing motor nerve conduction studies?
Tibial Nerve
Which nerve innervates the Abductor Hallucis Brevis muscle, supplies sensation to the medial anterior sole of the foot, and 1st through medial aspect of the 4th toes?
Medial Plantar Nerve
What nerve innervates the Abductor Digiti Quinti Pedis, supplies sensation to the lateral sole of the foot, and lateral 4th and 5th fifth toes?
Lateral Plantar Nerve
What is a pure sensory nerve and supplies sensation to the posterolateral leg and lateral aspect of the foot?
Sural Nerve
The laryngeal muscles receive innervation from what nerves?
Glossopharyngeal, Vagal, and cranial root of the Accessory Nerve
What nerve supplies the tongue?
Hypoglossal
What nerves control movement of the eyes?
Oculomotor, Trochlear and Abducens Nerves
What nerve supplies superficial sensation to the face and the buccal and nasal mucosa?
Trigeminal Nerve
What nerve innervates muscles for facial expression?
Facial Nerve
What nerve innervates the muscles of mastication?
Trigeminal Nerve
The Sternocleidomastoid and upper portion of the Trapezius muscles are innervated by what nerve?
Spinal root of the Accessory Nerve
What nerve supplies the diaphragm?
Phrenic Nerve
What nerve innervates the Supraspinatus and Infraspinatus muscles?
Suprascapular Nerve
When a patient has scapular winging, what nerve should be tested?
Suprascapular Nerve
What nerve innervates the Serratus Anterior muscle?
Long Thoracic Nerve
What nerve innervates the Deltoid muscle?
Axillary Nerve
Clinical symptoms usually consist of distal upper limb weakness and atrophy, with proximal muscles showing hypertrophy. Reflexes are usually normal or increased. Motor fibers most involved, while sensory fibers stay normal through the sites of conduction block. Conduction block suggests chronic demyelination. The conduction blocks usually do not involve the common sites of compression, but sites such as the median nerve in the forearm. This describes?
Multifocal Motor Neuropathy
What disease usually begins in the 5-7th decades, distal weakness is a common symptom and is a result of an anterior horn cell disorder that causes muscle wasting and denervation of muscle fibers?
Amyotrophic Lateral Sclerosis
The clinical features are flu-like symptoms developing to a paralytic illness affecting one or more limbs. Muscle atrophy, but a normal sensory exam. NCS tend to show normal velocities with reduced CMAPS relative to the muscle atrophy. This describes?
Poliomyelitis
What disorder is characterized by degeneration of anterior horn cells and is a neurologic disorder of childhood?
Spinal Muscular Atrophy
Sensory neuronopathy is an example of what kind of disorder?
Disorder involving the dorsal root ganglion
What lies outside the spinal cord along the dorsal spinal root and contains sensory cell bodies?
Dorsal Root Ganglion
What is a disease or disorder that affects the nerve at the spinal root?
Radiculopathy
What is a disease or disorder that affects the nerve at the spinal root and affects more than one level?
Polyradiculopathy
This occurs when the nerve is torn from the attachment at the spinal cord.
Root Avulsion
What can result from an avulsion of C5-C6 nerve roots and occurs from a downward traction on the plexus?
Erb's Palsy
What disorder can be a result of an extra first rib (cervical rib) or an old fracture of the clavicle that reduces the space for the vessels and nerves? Patient may have symptoms of pain and paresthesias in the neck, shoulder, forearm and hand and may have weakness in the hand.
Neurogenic Thoracic Outlet Syndrome
Also called neuralgic amyotrophy or brachial plexitis. The first symptom is usually pain, often severe with muscle atrophy to follow. When the pain subsides, weakness becomes apparent. Isolated nerves may be affected or all of the plexus may be involved. Most cases are unilateral. This describes?
Parsonage Turner Syndrome
What is a condition where the Median Nerve is compressed at the wrist as it travels under the transverse carpal ligament?
Carpal Tunnel Syndrome
Between the epicondyle and olecranon, a place where the ulnar nerve can become compressed. This describes?
Condylar Groove
Chronic compression of the Ulnar Nerve in the channel between the two heads of the Flexor Carpi Ulnaris 1-4 cm distal to the medial epicondyle of the elbow. This describes?
Cubital Tunnel Syndrome
The area where the Ulnar Nerve enters the wrist between the hook of the hamate and pisiform bones, the approximate location that the main Ulnar trunk splits into the superficial and deep branches. This describes?
Guyon's Canal
Prior trauma or osteoarthritis that gradually causes damage to the Ulnar Nerve at the epicondylar groove is sometimes called?
Tardy Ulnar Palsy
Radial Nerve compression at the spiral groove from prolonged immobility. This describes?
Saturday Night Palsy
What disorder has findings that include an asymmetric sensory and motor peripheral neuropathy involving damage to multiple nerves in separate areas of the body along with multiple mononeuropathies?
Mononeuritis Multiplex
The condition in which the Tibial Nerve is compressed as it travels under the Flexor Retinaculum. Associated symptoms are pain and paresthesia of the sole.
Tarsal Tunnel Syndrome
What nerve is affected if there is a foot drop, and slowing across the knee?
Peroneal Nerve at the fibular head
Characteristic findings of wasting and weakness of distal limb muscles also usually associated with distal sensory loss, moderate foot deformities, and decreased or absent deep tendon reflexes describes the hereditary disorder called?
Charcot Marie Tooth (CMT)
Markedly prolonged distal latencies, markedly slowed conduction velocities, and markedly prolonged or absent late responses are characteristics of_______.
Diffusely Demyelinating Polyneuropathy
Motor and sensory amplitudes decrease, with normal or slightly slowed distal latencies, late responses and conduction velocities, are characteristics of_____.
Axonal Polyneuropathy
A demyelinating polyneuropathy that is an autoimmune disorder, 20% of patients have respiratory symptoms and prolonged F Waves in NCS; generally an acute process. This describes?
AIDP - Acute Inflammatory Demyelinating Polyneuropathy
The acronym CIDP stands for?
Chronic Inflammatory Demyelinating Polyneuropathy Is an acquired motor and sensory demyelinating neuropathy that often has axonal features. Characterized by prolonged latencies, slowed conduction velocities, absent or prolonged F-waves. Sensory NCS have low amplitudes especially in the lower extremities
What type of neuropathy develops after the administration of various drugs or exposure to chemical substances, such as arsenic?
Toxic Neuropathy
What type of neuropathy can occur from a nutritional disturbance or vitamin B 12 deficiency, such that is seen in pernicious anemia?
Metabolic neuropathy
What is an inherited genetic muscle disease characterized by progressive muscle weakness and muscle fiber degeneration?
Muscular Dystrophy
What is a disease of the muscles that classically has a proximal more than distal pattern of weakness?
Myopathy
The symptoms of progressive proximal muscle weakness and increased Creatine Kinase, are primary symptoms of _______.
Polymyositis
If an extremity is cold, what effects will be seen in the conduction velocity?
Decreased conduction velocity
If an extremity is cold, what effects can be seen in the latencies?
Prolonged latency
If an extremity is cold, what effects can be seen in the amplitude?
Increased Amplitude
How does temperature effect repetitive nerve stimulation?
RNS may result in false negative results. The skin temperature must be warm to avoid false negative results. Cool temperatures will often mask abnormalities that are otherwise present. This is more problematic in presynaptic disorders of neuromuscular transmission.
Why is warming the limbs necessary before performing Nerve Conduction Studies?
Cold extremities can decrease the conduction velocity, prolong the latency and increase the amplitude. One technique to use would be a warming bath
How does age factor in nerve conduction studies?
Children under 5 and adults over 60 should have their own set of normative data since amplitudes and conduction times are affected by age.
What affect does height and limb length have on the conduction velocity?
The taller the person, the longer the limb and the more tapered the distal nerve. Conduction velocity is directly proportional to nerve diameter and so the more distally tapered nerves in taller individuals conduct more slowly.
Involves axons traveling anomalously from the Median to the Ulnar Nerve in the forearm and terminating in intrinsic hand muscles. There are three types depending on where they terminate: Type I (Hypothenar-Abductor Digiti Minimi), Type II (First Dorsal Interosseous), Type III (Abductor Pollicis Brevis)
Martin-Gruber Anastomosis
How does Martin-Gruber Anastomosis to the Abductor Digiti Minimi muscle (ADM) present itself on nerve conduction studies?
Ulnar motor study to the ADM has a greater than 20% drop in amplitude at the elbow when compared to the amplitude at the wrist and you have ruled out all technical problems.
How does Martin-Gruber Anastomosis to the First Dorsal Interosseous muscle (FDI) present itself on nerve conduction studies?
Ulnar motor study to the FDI has a greater than 20% drop in amplitude at the elbow when compared to the amplitude at the wrist and you have ruled out all technical problems.
How does Martin-Gruber Anastomosis to the Abductor Pollicis Brevis muscle (APB) present itself on nerve conduction studies?
Median motor study has larger amplitude at the elbow than amplitude at the wrist and you have ruled out all technical problems.
An anastomosis of motor fibers between the Median and Ulnar nerve at the level of the palm.
Riche Cannieu Anastomosis
This is an anomalous innervation where the Extensor Digitorum Brevis derives additional innervation from the _______, a branch of the Superficial Peroneal nerve which curves around the lateral malleolus and descends more laterally.
Accessory Peroneal Nerve
How do you prove the anomaly of the Accessory Peroneal Nerve?
Stimulate posterior to the lateral malleolus, (if it is a clean and negative onset, and not volume conducted response) add this amplitude to the distal amplitude and it will closely equal the proximal site.
Recording electrodes should be large enough to record a potential from all the muscle fibers, what is a standard electrode size?
0.5-1.0 cm in diameter for a surface disc electrode.
Which direction should the stimulating electrode be positioned for correct polarity when stimulating a motor or sensory nerve conduction study?
The cathode (negative pole) is positioned towards the active recording electrode.
What distance should the reference electrode be from the active electrode in a sensory nerve conduction study?
3.0 to 4.0 cm Amplitude of the sensory study may be reduced if electrodes are not kept standard at 3-4 cm apart.
For accurate electrode placement, where should the recording electrode be placed for a sensory nerve conduction recording?
Directly over the nerve The recording electrode should be place directly over the nerve and the reference should be placed 3-4 cm distal to the recording electrode.
For accurate electrode placement, where should the recording and reference electrodes be placed for a motor nerve conduction study?
The recording electrode should be placed over the "belly" of the muscle being tested and the reference on an associated tendon distal to the recording electrode.
To reduce_____________, before applying electrodes, make sure the patient's skin is clean and free of dirt and oils, if necessary the skin may need to be abraded.
Impedance
What is the most common cause for error in nerve conduction studies?
Measurement errors Be consistent with distances, a slight measurement error can skew your results. The error is proportionately much greater over shorter distances and is much less of a problem over longer distances. A 1 cm measurement error over a 10 cm distance would give a 10% error, while the same 1 cm error over a 100 cm distance will give only a 1% error.
How does limb position affect nerve conduction studies?
Limb position can affect measurements, amplitudes, latencies, and conduction velocities. (Care must be used when taking measurements, flexion of the extremities will affect the measurements.)
Nerve conduction propagation of an impulse in a direction other than (opposite) the normal physiological direction.
Antidromic Conduction
Nerve conduction propagation of an impulse in a normal (same) physiologic direction.
Orthodromic Conduction
Check that ground and recording electrodes are functioning properly, make sure stimulator is working, check if cables are crossed or touching, check parameter settings and amplifier input jacks. These are examples of?
Equipment Troubleshooting Techniques
Modes of Transmission for infection can occur with exposure through contact. The first form of contact, ______ transmission, occurs when the pathogen is transmitted from the infected individual. While _____transmission occurs when an inanimate object serves as the temporary agent; when the person comes in contact with the object they become infected.
Direct; Indirect
Modes of Transmission for infection can occur with exposure through contact (direct or indirect) and _______ or _______.
Airborne (diseases such as Pulmonary Tuberculosis are transmitted this way); Droplet (diseases or conditions transmitted by large respiratory droplets that are generated by coughing, or sneezing from the infectious individual to susceptible mucosal surfaces of the recipient)
What is proper disinfection of non-disposable electrodes?
After every NCS, surface electrodes should be cleaned with a 1;10 dilution of bleach or 70% isopropyl alcohol. Clean and disinfect electrodes and sensors according to manufacturer's specifications, state and local health policies, and Occupational Safety and Health Administration (OSHA) guidelines Preston, David and Barbara S
Standard precautions in the healthcare setting consist of what 5 practices?
1) Hand hygiene 2) Use of personal protective equipment (e.g., gloves, gowns, masks) 3) Safe injection practices 4) Safe handling of potentially contaminated equipment or surfaces in the patient environment 5) Respiratory hygiene/cough etiquette.
Name six equipment safety rules technologists should follow:
1) Keep instrument plugged into hospital grade, 3-prong outlet 2) Keep power cables tightly connected 3) Comply with hospital safety checks 4) Use only one ground to prevent ground loops 5) Do not power up equipment when patient is connected 6) Read and follow all operator manual requirements
When could leakage current be highest?
When the equipment is turned on and extension cords are used. Therefore eliminate extension cords and place ground electrodes close to true electrical neutral, the ground lead will allow a pathway for stray current leaks to harmlessly dissipate.
Patients who have pacemakers and/or defibrillators and intra-cardiac catheters may be considered _________.
Electrically sensitive
The privacy and security rule that provides federal protection for individually identifiable health information, offering a series of administrative, physical and technical safeguards to assure confidentiality, integrity and availability of electronic protected health information.
HIPAA (Health Insurance Portability and Accountability Act)
A federal agency charged with the mission to assure a safe and healthy workplace by setting and enforcing standards. They provide training, education and assistance to achieve this.
OSHA (Occupational Safety and Health Administration)
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