Neurologic Diagnostic Studies Flashcards
(54 cards)
Safe, painless recording of the cortical electrical activity
Electroencephalogram (EEG)
EEG involves _____ paired of electrodes applied to the scalp
8-16
Readings taken awake and/or asleep
Temporary vs. continuous monitoring
Indications for EEG
Seizure disorders**
Metabolic encephalopathy
Distinguish between cortical and subcortical
Tumors
Why might an EEG be normal in a seizure patient?
B/c seizures are EPISODIC events - unless you’re monitoring at the moment the seizure occurs, you may not see EEG changes
Why use EEG in metabolic encephalopathy?
To distinguish focal from generalized slowing
What is the difference between cortical and sub-cortical injury?
Cortical: See neglect, aphasia, and hemianopia
Sub cortical: See motor hemiparesis
What are the different types of rhythms in EEG?
Alpha = 8-12 Hz
Beta = >12 Hz
Theta = 4-8 Hz
Delta = 0-4 Hz
What type of EEG rhythm do you normally see in awake adults?
Alpha (8-12 Hz)
EEG findings:
Epileptiform activity
Seizures
EEG findings:
Focal discharges/spikes c/w focal problem
Tumor, infarct, scar tissue
EEG findings:
Generalized changes/slowing c/w metabolic disorders
Encephalopathy, anoxia
EEG findings:
Psychogenic seizures —> normal EEG w/ presence of “seizure” activity
Get them on inpatient monitoring unit
What are the contraindications for EEG?
NONE (YAAAAY!)
Should be interpreted by neurologist who specializes in EEG
Clinical examination of the electrical activity of muscle fibers/motor unit used to define location of problems affecting peripheral nerves
Electromyogram (EMG)
EMGs differentiate ________ conditions form ___________
Primary muscle conditions
Muscle weakness caused by neurologic disorders
How is an EMG performed?
Needle electrode(s) inserted into skeletal muscle to record electrical potentials —> look for abnormal activity
Electrical activity of the muscle is evaluated during: • Needle insertion • Spontaneous activity at rest • Slight muscle contraction • Full muscle contraction
The ________ provides information about the muscle’s ability to respond when the nerves are stimulated during an EMG
Presence, size, and shape of the wave form (the action potentials)
EMG indications
Lower motor neuron disease (ie ALS)
NMJ disease (ie Myasthenia gravis)
Muscle disease (myopathy)
Peripheral nerve disorders (ie carpal tunnel, peripheral neuropathy)
Others: alcoholic neuropathy, brachial plexopathy, cervical spondylitis, denervation, Guillain-Barre, muscular dystrophy, nerve dysfunction, polymyositis
What will EMG show in NMJ disease such as Myathenia gravis?
Fatigability
What will EMG show in muscle disease (myopathy)?
Decreased amplitude of motor response
Study used to assess the rate of conduction and the amplitude of response of peripheral nerves
Nerve conduction studies
Tests how well and how fast the nerves can send electrical signals
Nerve conduction studies are usually performed in conjunction with …
EMG
How do nerve conduction studies work?
Electrical stimulation of peripheral nerve will produce muscle contraction or a sensory response
Recording electrode and stimulating electrodes are placed over nerve or muscle
Indications for Nerve Conduction Studies
To differentiate between primary nerve and muscle disorders
To differentiate lower motor neuron diseases from peripheral neuropathy
Detect abnormalities in sensory nerves
Axonopathy
Demyelination process
