Nerve function in your hands is assessed using several methods, primarily focusing on nerve conduction velocity and electromyography (EMG).
Nerve Conduction Studies (NCS)
A nerve conduction study (NCS) measures how quickly electrical signals travel through your nerves. This helps identify nerve damage or dysfunction. The procedure involves placing electrodes on your skin. These electrodes deliver small electrical impulses to stimulate your nerves. The speed at which the signal travels is then measured. This is done in several locations on the hand and arm to assess different nerves. As described in one reference, "Nerves which supply sensation are tested by putting rings on individual fingers from which you will feel a repetitive tapping/tingling sensation for a short time. This is recorded by an electrode at the wrist and then measurements will be taken between the electrodes. This will be repeated on one or two other fingers." (Source). Other sources mention stimulating nerves in arms and legs to evaluate pain, numbness, and weakness (Source).
Electromyography (EMG)
Electromyography (EMG) assesses the electrical activity of your muscles. A small needle electrode is inserted into the muscle to measure its electrical activity both at rest and during contraction. This helps to diagnose muscle disorders and problems with the nerves that control those muscles. One reference describes EMG as "the recording of the electrical activity that your muscle naturally produces" (Source). EMG tests are often performed in conjunction with nerve conduction studies to get a more comprehensive picture of nerve and muscle health. (Source).
Clinical Tests
Besides NCS and EMG, your doctor may perform clinical tests to assess nerve function. For instance, Phalen's test is a common clinical test for carpal tunnel syndrome, which involves flexing your wrists for a period of time and observing for symptoms such as numbness or tingling. (Source, Source).
Summary of Testing Methods:
- Nerve Conduction Velocity (NCV): Measures the speed of electrical signals in your nerves.
- Electromyography (EMG): Measures the electrical activity of your muscles.
- Clinical Tests (e.g., Phalen's test): Assess nerve function through specific movements and positions.
