Neurophysiology Clinical Applications ; Lecture Flashcards
What are the three main tests in clinical neurophysiology?
Nerve conduction studies (NCS) and electromyography (EMG).
Electroencephalography (EEG).
Evoked potentials (somatosensory, visual, transcranial magnetic stimulation).
Neurophysiology primarily investigates the _________ nervous system, brain, spinal cord, and _________ nerves.
peripheral; optic.
True/False: Evoked potentials assess sensory, visual, and motor pathways.
True.
What do nerve conduction studies (NCS) measure?
The size and speed of nerve responses.
Small responses in NCS indicate _________ loss, while slow responses suggest _________ loss.
axonal; myelin.
What condition is characterized by focal slowing across the elbow in NCS?
Ulnar neuropathy.
True/False: NCS can differentiate between motor and sensory nerve dysfunction.
True.
What does EMG measure?
The electrical activity of individual motor units in muscles using needle electrodes.
EMG identifies _________ motor units in nerve pathology and _________ motor units in muscle pathology.
large; small.
True/False: EMG is crucial in diagnosing myopathies where NCS may appear normal.
True.
What abnormality does EMG detect in Myasthenia Gravis?
Increased “jitter” due to impaired neuromuscular transmission.
EMG is more _________ than antibody tests for diagnosing Myasthenia Gravis.
sensitive.
What is the primary clinical use of EEG?
Evaluating seizures and epilepsy.
Focal EEG abnormalities indicate _________ hemisphere involvement, while generalized abnormalities affect _________ hemispheres.
one; both.
True/False: EEG can be used intraoperatively to monitor for changes in brain activity.
True.
What is the purpose of intracranial EEG?
To localize seizure origins in patients with medically intractable epilepsy being considered for surgery.
What are the three types of evoked potentials?
Somatosensory evoked potentials (SSEPs).
Visual evoked potentials (VEPs).
Transcranial magnetic stimulation (TMS).
SSEPs assess the integrity of the _________ columns by stimulating peripheral nerves and recording from the somatosensory cortex.
dorsal.
What is the main use of visual evoked potentials (VEPs)?
To assess for demyelination of the optic nerves, commonly in multiple sclerosis (MS).
True/False: SSEPs are used in intraoperative spinal cord monitoring
true
How does transcranial magnetic stimulation (TMS) work?
A magnetic pulse induces an electric current in the motor cortex, which excites motor pathways and elicits a motor evoked potential in a target muscle.
TMS can assess the _________ of the motor cortex and the integrity of _________ motor pathways.
excitability; central.
True/False: TMS is only a diagnostic tool.
False (it is also used therapeutically for severe depression).
In which conditions are evoked potentials most commonly used?
Multiple sclerosis (MS).
Intraoperative spinal cord monitoring.
Visual pathway assessment.
EEG during _________ can classify epilepsy syndromes into focal or generalized types.
seizures.
True/False: Large motor units seen on EMG suggest nerve or motor neuron pathology.
True
What does NCS evaluate in peripheral neuropathies?
Axonal neuropathies (small responses).
Demyelinating neuropathies (slow responses).
EMG is critical for diagnosing conditions like _________, where NCS may appear normal.
myopathies.
Why is intraoperative SSEPs monitoring important?
It detects early spinal cord compromise, allowing surgical intervention before permanent damage occurs.
True/False: Neurophysiological testing plays a limited role in diagnosing and managing neurological disorders.
False.
