What they are: A group of tests performed to assess the electrical activity and function of your brain, nerves, and muscles, helping to diagnose neurological disorders.
How they’re done:
EEG (Electroencephalogram): Small metal discs (electrodes) are attached to your scalp to record the electrical activity of your brain. It’s non-invasive and painless.
EMG (Electromyography) and NCS (Nerve Conduction Studies): For NCS, electrodes are placed on your skin, and mild electrical impulses are delivered to measure nerve speed and strength. For EMG, a very thin needle electrode is inserted into specific muscles to record their electrical activity at rest and during movement.
Evoked Potentials (EPs): Electrodes are placed on your scalp and other areas to measure brain activity in response to specific sensory stimuli (e.g., flashing lights for visual, clicking sounds for auditory, small electrical pulses for somatosensory).
PSG (Polysomnography) / Sleep Study: This is an overnight test performed in a specialized lab. Electrodes and sensors are placed on your head, face, chest, and legs to monitor brain waves, eye movements, muscle activity, heart rate, breathing, and oxygen levels while you sleep.
Time: Varies significantly by test: EEG (30 mins – 2 hours), EMG/NCS (30 mins – 2 hours), Evoked Potentials (30 mins – 1 hour each), PSG (8-10 hours overnight).