Is an EMG painful? Yes. There is some discomfort at the time the needle electrodes are inserted. They feel like shots (intramuscular injections), although nothing is injected during an EMG.
Electromyography (EMG) is a diagnostic procedure to assess the health of muscles and the nerve cells that control them (motor neurons). EMG results can reveal nerve dysfunction, muscle dysfunction or problems with nerve-to-muscle signal transmission.
How long do they take? An EMG may take 30 to 60 minutes. Nerve conduction tests may take from 15 minutes to 1 hour or more. It depends on how many nerves and muscles your doctor tests.
You may feel a little pain or cramping during an EMG test. You may have a tingly feeling, like a mild electric shock, during a nerve conduction study.
The signs of nerve damage
How do I prepare for electromyography?
It is rare that patients need sedation. If you feel you need something, Valium or one of its relatives, (Xanax, Ativan), is usually prescribed. You need to be awake for the procedure, so whatever you take should allow you to be relaxed and not asleep. Plan on resuming normal activities after the procedure.
You may need to stay in the outpatient facility or hospital for a short period after your EMG. Your team will apply warm compresses to your injection sites to reduce pain. You will not be able to drive for about 24 hours if you had sedation because you will still be drowsy.
Are taking any drugs. Certain drugs that act on the nervous system (such as muscle relaxants) can interfere with electromyography results. You may need to stop taking these three to six days before the test. Have had bleeding problems or are taking blood thinning drugs, such as warfarin (Coumadin®) or heparin.
Do not eat or drink foods that contain caffeine (such as coffee, tea, cola, and chocolate) for 2 to 3 hours before the test. Wear loose-fitting clothing so your muscles and nerves can be tested.
An abnormal EMG result will present a bizarre pattern, with strange wave shapes. There is electrical activity even while at rest, and the electrical activity (produced by motor neurons) is abnormal during contraction of a muscle. Abnormal results indicate nerve dysfunction, muscle injury, or muscle disorders.
Immediate recall of pain was significantly decreased by ibuprofen, but memory of pain and residual needle site pain a day after EMG were not decreased. We conclude that ibuprofen is effective in reducing EMG pain as perceived immediately after the procedure. Premedication with ibuprofen before EMG is useful.
To prepare for an EMG, please do the following:
Five or more needle insertions may be necessary for the test. You may experience slight pain with the insertion of the electrode, but it is usually painless. If the test is painful you must tell your examiner because this can interfere with the results.
You do not have to fast; you may eat and drink as normal. If the EMG will be on your arm(s), then please wear or bring a short sleeve top. If the EMG will be on your leg(s), then please wear or bring shorts.
An EMG or NCS may cost from $150 to $500. An SEP may cost much more than $350.
Do not take any Excedrin (which contains Aspirin), over-the-counter anti-inflammatory medications (such as Advil, Aleve, Aspirin, etc.), or prescription NSAID's (naproxen, motrin, etc.) for at least 5 days prior to the procedure.
Caffeine, via its adenosine-receptor antagonism, may increase the firing rates of central neurons (10). If this is the case, the increase in firing rates could offset the decrease in motor unit recruitment so that the force-EMG relationship would appear unaltered.
Smoking increased heart rate more for paratelic than for telic dominant subjects; there were no gender-related differences. EMG activity was higher when telic compared to paratelic dominant subjects were deprived from smoking and smoking decreased EMG activity more for telic than for paratelic dominant subjects.
You must stay at a normal body temperature. Being too cold or too warm alters nerve conduction and can give false results. Tell your doctor if you have a cardiac defibrillator or pacemaker. Special steps will need to be taken before the test if you have one of these devices.
The first meta-analytic investigation on the topic of caffeine and strength was performed by Warren et al. , who found a mean increase of approximately 7% in lower body maximal voluntary contraction with caffeine ingestion.