This set of Clinical Science Multiple Choice Questions & Answers (MCQs) focuses on “Electromyography”.
1. What is a neuro-muscular disorder?
a) The nerves are damaged so they do not give proper impulses to the muscles
b) The muscles are damaged and so they are not able to act according to the impulses given by the nerves
c) The nerves are damaged so they do not give proper impulses to the muscles or the muscles are damaged and so they are not able to act according to the impulses given by the nerves
d) Nerves and muscles are both damaged
Explanation: Neuro-muscular disorders are those in which either the neurons or the skeletal muscles have faced some sort of injury or damage and the effect of that is seen in the skeletal muscles or neurons. For eg, the nerve is able to conduct impulses but due to damaged skeletal muscles, they are not able to respond to the impulses.
2. Which of them is a neurological disorder which is expressed muscularly?
b) Muscular Dystrophy
Explanation: In paralysis, the muscles are functioning normally but the nerves are unable to conduct the impulses. If the neurons are not treated, the muscles lose their tone over time and become stiff. In that situation, the muscles have also been damaged.
3. Which of them is a muscular disorder?
b) Muscular Dystrophy
Explanation: In Muscular Dystrophy, the muscles have become weak due to the absence or reduction of a protein, dystrophin, which disrupts normal muscle function. It causes muscle weakness and so they are not able to contract properly even if they receive the signal from the nerves.
3. An EMG acquires signals by the relaxing muscle fibers.
Explanation: When the muscles receive impulses, they work by contracting. Thus, we can say that contraction is an active process where energy is expanded while muscle straightening is a passive process where the muscle goes back to their original shape and structure. Thus, impulses are generated in the contraction process and thus are recorded by the electrodes.
4. The typical range of EMG can be _______
a) 0 – 1 mV
b) 1 – 5mV
c) 0 – 0.1 mV
d) 0.1 – 0.5 mV
Explanation: EMG signals are very faint. This can be because either the muscles generate the signals of small amplitudes or the signals have to go through the muscles before the electrodes can pick them. Thus, the signals acquired are of small amplitude and of a small range.
5. The use of EMG during surgery is to monitor _____________
a) the neuromuscular function with neuromuscular blocking drug during general anaesthesia
b) the muscle tone during surgery
c) the muscle movement during surgery
d) the presence of impulses in muscles during surgery
Explanation: In order to allow blood to flow normally, muscles also play an important part. Thus, during surgery, EMG waves are taken to ensure the even spread when a general anesthesia is given. This anesthesia contains neuromusclular drugs so that the pain perception goes down during surgery and so the body does not react when in surgery. If this is monitored properly, it may cause pareses (temporary or permanent loss of muscular function) in future.
6. The following is an image of an adhesive surface electrode. What are its possible advantages?
ii) do not need electrode gel
iii) cover a larger surface area
iv) no pain while usage
v) risk of infection
a) i, ii, iii, iv, v, vi
b) i, ii, iv, vi
c) i, ii, iii, iv, v
d) ii, iii, iv
Explanation: The surface electrodes are adhesive in nature, i.e. the surface has a sticky coating which allows them to be stuck on the skin naturally. The areas around the electrodes are coated with electrode gel to allow better signal reception. Due to its size, it covers a better surface area. These electrodes are mostly disposable so the risk of infection is low. Since they must be mass produced and then disposed, they are not so costly.
7. In order to take EMG, there exists a special electrode of 25μ diameter and 14 needles like pick up surfaces. What is this electrode used for?
a) Deeper penetration of muscle to take ECG
b) The larger surface area is covered
c) Multiple signals from the same muscle
d) Individual signals from individual muscle fibers
Explanation: The needles of the electrode increase the surface area and allow for all the needles to pick up signals from every fiber of the muscle individually. This way, the signals from every muscle fiber can be analysed and it is easier to point out the damaged area more accurately.
8. How does signal delay and triggering unit help in EMG?
a) It delays the incoming signal and allows the current signal to be processed properly
b) The delayed signals keep the system working for a longer time
c) The delayed signal is actually signal acquired from individual muscles
d) The delayed signal provides clarity in processing
Explanation: The signal delay and trigger unit of EMG is used to examine signal from individual muscle fibers. For this purpose, there is a special electrode of 25 micron diameter which has 14 needles like pick up surfaces. In order to receive and analyze signals properly, a delaying sweep is used. This allows for the signal to be taken from every needle individually, one at a time. This allows for better processing of the signal as well.
Sanfoundry Global Education & Learning Series – Clinical Science.
To practice all areas of Clinical Science, here is complete set of 1000+ Multiple Choice Questions and Answers.