Acupuncture like needles are inserted into certain muscles to measure electrical activity and wave formation. Often painful but excellent for diagnosis of muscle and nerve diseases. Risk of bleeding if on anticoagulants. Very useful in localizing pinched cervical and lumbosacral nerve roots. Potentials A measure of nerve conduction time from peripheral to central nervous system from eye, ear, or limbs.
Information is gathered about brain and nerve function.
Still useful for 8th cranial nerve problems by brain stem auditory evoked potential. Sometimes used to monitor brain function under anesthesia. Ultrasound Safe test using sonar to generate a picture of carotid arteries in the neck and to estimate blood velocity. Transcranial Doppler Ultrasound Safe test that uses sonar to measure intracranial artery blood velocity. Mainly used to check for spasm after subarachnoid hemorrhage.