Clinical Neurophysiology Lab (EEG/EMG)

The CMC Clinical Neurophysiology Laboratory offers sophisticated diagnostic procedures to help neurologists identify neurological conditions and develop treatment plans. It uses measurement of electrical activity from the central and peripheral nervous system to help in the diagnosis and management of a wide range of neurological conditions in all age groups. The core investigations are electroencephalography (EEG) and nerve conduction studies (NCS) with electromyography (EMG), which are mostly performed on outpatients and constitute the largest part of clinical neurophysiology workload.

Electroencephalography (EEG)

Electroencephalography is a valuable diagnostic aid in the assessment of brain disorders. By recording electrical activity from the scalp, infectious diseases of the nervous system, head trauma, cerebrovascular accident, epilepsy and brain tumor can be evaluated. EEG findings also contribute as an indicator of brain function in metabolic disorders and in the evaluation of organic causes of psychiatric and behavioral adjustment problems in children. It also plays a role in the confirmation of cerebral death.

The department provides electroneurodiagnostic services for in patients and out-patients both for adults and pediatric cases. Electroneurodiagnostic technology is the scientific field devoted to the recording and study of electrical activity of the brain and nervous system. Electroencephalography (EEG) is a brain wave test. It detects abnormalities in the electrical activity of the brain. This helps diagnose seizure disorders, head injuries, sleep disorders, and causes of unconsciousness.

EEG is a painless test that records the brain electrical activity through electrodes attached to the head. An EEG does not treat or cure illness, read your mind, give you a shock, or measure your IQ. EEG helps doctors determine if the brain’s electrical activity is causing seizures. The CMC Clinical Neurophysiology Laboratory is using the latest technology, with new machines EMG and EEG can be performed more cost effective, in a system that is easy to operate, as well as comprehensive in analysis.

Electromyography (EMG)

Electromyography and Nerve Conduction Velocity Studies (EMG-NCS) are neurophysiologic examinations that record the electrical activity of the peripheral nervous system and muscles. The procedure is regarded as an extension of the neurological examination. They provide information on the integrity of the peripheral nervous system, neuromuscular junction and muscles. Vital information may be provided that may help determine if a problem involves the nerves or the muscles, or if it is of a more central etiology as from either the brain or spinal cord. More frequently, the EMG study is utilized as an aid in the diagnosis of cervical and lumbosacral radiculopathies, plexopathies and distal neuropathies. It is also very important in the diagnosis of muscle diseases.

A routine examination consists of two parts, the nerve conduction study which is accomplished by a neurophysiology technician and the electromyography proper performed by a physician electromyographer or neurophysiology consultant. During both procedures the patient will be asked to lie down or sit comfortably depending on what part of the body will be tested. Certain areas of the skin will be cleansed. In NCS, recording and ground electrodes are attached to the skin. A stimulating electrode (stimulator) is held against particular points along the course of the nerve being studied. Low voltage pulses delivered to a specific nerve through the skin is harmless and is tolerated by all patients.

In electromyography, a disposable needle electrode is inserted into a specific muscle which may be felt as a dull ache or pressure. Other electrodes will also be attached to the skin for electrical grounding and reference, they may also be moved to get the readings from different sections of the muscle. The muscle examined will be tested at rest and during contraction. Other muscles are tested depending on the working diagnosis or the presenting symptoms. In the hands of an experienced electromyographer, the examination is generally well tolerated.

In addition to precise clinical examination and neuro-physiological functional diagnosis with EEG, EMG and evoked potentials, we also increasingly use imaging methods such as computer tomography (CT) and magnetic resonance imaging (MRI) of the skull and spinal cord, as well as nuclear medicine scintigraphic methods. A further diagnostic focus is placed on extracranial and transcranial Doppler sonography of the cerebral vessels.