The electrical activity of brain is recorded by this test. The record is analysed for abnormalities in brain rhythm.
The EEG is useful for diagnosis to decide about medication, in monitoring the response to treatment and in long term follow up to evaluate the course of the disease.
The EMG test is used to evaluate the status of the muscles, nerves, roots and anterior horn cells. A number of neurological disorders present with weakness or atrophy (thinning) of muscles.
Some common disorders are:
The EMG may be done either alone or in combination with nerve conduction studies (NCS) depending on the neurological disorder.
Repetitive nerve stimulation tests are a special type of nerve conduction study. Rather than a single electric shock, a brief series of shocks is applied to a motor nerve and responses are recorded from a muscle supplied by that nerve. The study is generally performed before and after brief exercise of the muscle. Serial response amplitudes are recorded. Repetitive nerve stimulation is useful for evaluating myasthenia gravis and other disorders of neuromuscular transmission.
VEP provides information regarding conduction in visual pathway from the retina to brain (occipital cortex).
VEP is recommended for following diseases:
This test examines the integrity of auditory pathway through the brainstem. The sound enters ear canal and stimulates auditory nerve. The electrical impulse travels from auditory nerve through the brainstem to auditory cortex. During testing, the patient hears the repetitive click sound through the earphone.
This test examines the sensory system from the peripheral nerve to the sensory cortex of brain. Weak electrical stimuli are applied to the peripheral nerve, for example median or ulnar nerve for upper extremity study and tibial nerve for lower extremity study.