Clinical neurophysiology Flashcards
What do nerve conduction studies and EMG look investigate?
problems with the peripheral nerve and muscle
What does EEG investigate and what can it be used for?
electrical activity in the brain and can be used for altered states of consciousness and epilepsy
What are evoked potentials and what are they used to investigate?
visual and somatosensory
problems with central pathyway
What 2 pieces of information do nerve conduction studies use?
velocity and amplitude
How does nerve conduction work?
electrical pulse to peripheral nerve and see how much gets through and how quickly
How do sensory studies work?
Stimulating sensory nerve fibres in the fingers allows measurement of sensory and motor function separately
Why may there be conduction block?
demyelination of the nerve
What is the difference between a trapped nerve root and affected peripheral nerve signs?
trapped root - sensory in DRG so unaffected whereas motor nuclei are within the spinal cord
peripheral nerve - contains both fibres so both are affected
What is the physiology behind Myaesthenia Gravis?
antibodies against acetylcholine receptor making its effect less
Myaesthenia gravis symptoms
fatigue, weakness
What body part does Myaesthenia gravis usually affect and how does this present?
Eyes - diplopia and ptosis
2 ways to diagnose Myaesthenia gravis?
antibody detection - not always present and time consuming
Neurophysiology
2 Neurophysiology Myaesthenia gravis investigations
single fibre EMG
repetitive stimulation
What is EMG?
single fibre electrics to measure potential difference within the muscle
What is jitter? Why is it present?
When there is a difference between 2 fibres in the same motor unit - present when damage at NMJ
