S4 weakness Flashcards
What is weakness in one limb due to?
Problem with spinal or peripheral nerve.
What is generalised distal weakness due to?
Peripheral neuropathy.
What is generalised proximal weakness due to?
Myopathy.
What is weakness extending over one half of the body due to?
Cerebral hemisphere problem.
Which part of the motor system is at fault with:
increased tone, flexors and plantars?
UMN.
Which part of the motor system is at fault with:
decreased tone, flexors and plantars?
LMN.
When is an interference pattern seen on an EMG?
When the muscle is contracting as hard as it can.
What are fibrillation potentials on an EMG?
Spontaneous discharges by denervated nerve fibres.
How do motor units and the EMG change in neuropathic muscle problems?
Increased motor unit size (dead fibres compensated by sprouting).
More complex, longer and slower EMG.
How do motor units and the EMG change in myopathic muscle problems?
Motor units get smaller.
Smaller, shorter and more complex EMG.
How does denervation change the interference pattern on an EMG?
Able to pick out individual fibres as there are less of them.
How does myopathy change the interference pattern on an EMG?
Lower voltage and higher frequency EMG.
