Electromyogram (EMG) And Nerve Conduction Studies: Results

The EMG recording shows no electrical activity when the muscle is at rest. There is a smooth, wavy line on the recording with each muscle contraction.

The nerve conduction studies show that the nerves transmit electrical impulses to the muscles or along the sensory nerves at normal speeds (conduction velocities). Sensory nerves allow the brain to feel pain, touch, temperature, and vibration. Different nerves have different normal conduction velocities. Nerve conduction velocities generally get slower as a person gets older.

Electrical activity in a muscle at rest shows that there may be a problem with the nerve supply to the muscle. Abnormal wave lines when a muscle contracts may mean a muscle or nerve disorder, such as amyotrophic lateral sclerosis (ALS), post-polio syndrome, inflammation, or other muscle problems.

In nerve conduction studies, the speed of nerve impulses (conduction velocity) may be slower than what is normal for that nerve. Slower conduction velocities may be caused by injury to a nerve (such as carpal tunnel syndrome) or group of nerves (such as Guillain-Barré syndrome or post-polio syndrome). Nerve conduction velocities generally get slower as a person gets older.