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75 Cards in this Set
- Front
- Back
Normal Median Palmar Sensory Amplitude?
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>40 uV
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Normal Median Digital Sensory (2nd) Amp?
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>15 uV
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Normal Ulnar Plamar Sensory Amp?
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>11 uV
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Normal Ulnar Dig Sensory (5th) Amp?
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>5 uV
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Normal Radial Sensory Amp?
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>15 uV
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Normal Median Motor Amp?
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>3 mV
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Normal Ulnar Motor Amp?
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>5 mV
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Normal Peroneal Motor Amp?
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>2 mV
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Normal Tibial Motor Amp?
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>2 mV
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Normal Sural Sensory Amp?
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>5 uV
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Normal Median Palmar Sensory Latency?
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<2.3 ms
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Normal Median Dig Sensory (2nd) Latency?
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<3.7 ms
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Normal Ulnar Palmar Sensory Latency?
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< 2.2 ms
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Normal Ulnar Dig Sensory (5th) Latency?
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< 3.1 ms
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Normal Radial Sensory Latency?
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< 2.5 ms
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Normal Median Motor Latency?
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< 4.5 ms
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Normal Ulnar Motor Latency?
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<3.6 ms
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Normal Peroneal Motor Latency?
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< 6.6 ms
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Normal Tibial Motor Latency?
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< 6.6 ms
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Normal Sural Sensory Latency over 30?
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< 4.8 ms
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Normal Sural Sensory Latency under 30?
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<4.2 ms
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Normal Median palm sensory distance?
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8 cm
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Normal median dig sensory (2nd) distance?
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13 cm
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Normal ulnar palm sensory distance?
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8 cm
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Normal Ulnar dig sensory (5th) distance?
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11 cm
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Normal radial sensory distance?
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10 cm
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Normal median motor distance?
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7 cm
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Normal ulnar motor distance?
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7 cm
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Normal peroneal motor distance?
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8 cm
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Normal tibial motor distance?
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12 cm
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Normal sural sensory distance?
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14 cm
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Normal Upper extremity conduction velocity?
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>48 m/sec
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Normal Lower extremity conduction velocity?
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>42 m/sec
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Temperature range should be between 33-35 C. Each degree C below this, can make a _____ difference in conduction velocity?
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2 m/sec
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For each centimeter off in distance, there is a _____difference in latency?
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0.15 ms
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Grade I carpal tunnel syndrome is defined as _____
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>/= 0.5 ms difference between median and ulnar latency.
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Grade II CTS is considered moderate and defined as ___
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prolonged sensory
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Grade III CTS is considered moderate to severe disease and is defined as _________
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prolonged sensory AND prolonged motor
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Grade IV CTS is considered severe disease and is defined as _______________
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prolonged sensory and motor AND abnormal needle exam.
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Gain is set at _____ to ____ for motor NCS/
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2 mV to 5 mV per division
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Recording electrode is placed over muscle belly and the reference electrode is placed ____.
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Distally over the tendon
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duration of the electrical pulse in motor NCS is set to ____ms
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200 ms
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Normal nerve require a current in the range of ___ to ___ mA to achieve supramaximal stimulation.
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20 to 50 mA
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Current is slowly increased from a baseline of 0 mA by 5 to 10 mA to bring in more underlying nerve fibers generating a CMAP. When do you stop increasing current?
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20% further once observed CMAP no longer increases in size
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CMAP should be a ______ wave in which the initial deflection is upward (negative).
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Biphasic
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Latency represents these three separate processes?
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1) nerve conduction time from stimulus site to NMJ
2) Time delay across the NMJ 3) Depolarization time across the muscle |
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Latency measurements are made in "ms" and reflect ____
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only the fastest conducting motor fibers
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Amplitude is measured from ___to the ____
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baseline to the negative peak
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CMAP amp reflects ________
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number of muscle fibers that depolarize
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Low CMAP amplitudes most often result from ______
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loss of axons
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While not the most common cause for Low CMAP amp, low CMAP Amp can also occur in setting of ______, ____ and _____
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conduction block from demyelination, some NMJ disorders and myopathies
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CMAP duration is measured from ____ to ___
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from initial deflection from baseline to the first baseline crossing (ie negative peak duration)
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Duration of CMAP is a measure of ______
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synchrony (ie the extent to which each of the individual muscle fibers fire at the same time)
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Duration of CMAP characteristically increases in conditions that result in slowing of some motor fibers but not others as in _________
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demyelinating lesions
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Proximal latency is _____ than distal latency
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longer
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Distal motor latency includes _____, _____ and ____.
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1) conduction time along the distal motor axon to the NMJ
2) NMJ transmission time 3) muscle depolarization time |
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Proximal motor latency includes the same three factors in distal motor latency plus _____
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nerve conduction time between the proximal and distal stimulation sites
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Latency and conduction velocity only reflect the ______ fibers
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fastest conducting
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Slower conducting fibers participate in CMAP area and amplitude but are not reflected in ____ or ___.
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latency or conduction velocity
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For sensory NCS pulse of other 100 or 200 ms in duration is used with current range of ___ to ___ to achieve supramaximal stimulation in most normal nerves?
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5 mA to 30 mA
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Sensory nerve action potentials (SNAPs) are usually ___ or ____ waves?
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biphasic or triphasic
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Onset latency is measured from ___ to ___
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stimulus to the initial negative deflection from baseline for biphasic SNAPS or to the initial positive peak for triphasics SNAPs
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Peak latency is measured at ____ of the first negative peak
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midpoint
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the SNAP amplitude reflects the sum of all the _____
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individual sensory fibers that depolarize
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distance traveled divided by onset latency gives you this value in the Sensory NCS
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conduction velocity
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Axonal loss is evident by reduction in this parameter of NCS?
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reduced amplitude
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In axonal loss lesions, _____ and ____ are normal, provided that the largest and fastest conducting axons remain intact.
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conduction velocity and distal latency
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The typical pattern associated with axonal loss is one of ____ and preserved ______ and ______
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reduced amplitudes and preserved latency and conduction velocities
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with axonal loss lesions amplitudes decrease, conduction velocities are normal or slightly decreased BUT NEVER BELOW _____ of the lower limit of normal
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75%
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with axonal loss lesions amplitudes decrease and distal latencies are normal or slightly prolonged BUT NEVER GREATER THAN ________ of upper limit of normal
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130%
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on NCSs demyelination is associated with marked slowing of _____ and marked prolongation of _____
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slowing of conduction velocity (slower than 75% of lower limit or normal) and prolongation of distal latency (longer than 130% of upper limit or normal)
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Any motor, sensory or mixd nerve conduction velocity that is slower than ____ m/s in the arms or ____ m/s in the legs signifies unequivocal demyelination.
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slower than 35 m/s in arms and 30 m/s in legs
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reduced amplitudes in demyelinating lesions are seen when _______ is present
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conduction block
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A drop in CMAP area between proximal and distal stimulation of more than ____% denotes conduction block
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%50
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A drop in CMAP amplitude of more than ____% denotes a conduction block
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20%
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