These are common tests used to help diagnose a neurological condition:

• Brain scans are imaging techniques used to diagnose tumors, blood vessel malformations or hemorrhage in the brain. These scans are used to study organ function or injury or disease to tissue or muscle. Types of brain scans include computed tomography, magnetic resonance imaging and positron emission tomography. In most genetic or primary forms of dystonia routine brain scans are normal. In secondary dystonias, however, areas of brain injury may be observed.
• Computed tomography (CT) scan is a noninvasive, painless process used to produce rapid, clear two-dimensional images of organs, bones and tissues. Neurological CT scans are used to view the brain and spine. They can detect bone and vascular irregularities, certain brain tumors and cysts, herniated discs, epilepsy, encephalitis, spinal stenosis, a blood clot or intracranial bleeding in patients with stroke, brain damage from head injury and other disorders. CT scans are often normal in dystonia but may be abnormal in secondary dystonias, such as those that follow a severe head trauma or stroke.
• Magnetic resonance imaging (MRI) uses computer-generated radio waves and a powerful magnetic field to produce detailed images of body structures, including tissues, organs, bones and nerves. Neurological uses include the diagnosis of brain and spinal cord tumors, eye disease, inflammation, infection and vascular irregularities that may lead to stroke. MRI can also detect and monitor degenerative disorders such as multiple sclerosis and can document brain injury from trauma. A Functional MRI (fMRI) uses the blood’s magnetic properties to produce real-time images of blood flow to particular areas of the brain. Routine brain MRIs are often normal in primary dystonia but may show abnormalities in secondary dystonias, such as dystonia following a stroke or when it is related to other brain diseases. FMRIs may be abnormal in dystonia but are often done only as part of research protocols.
• Positron emission tomography (PET) scans provide two- and three-dimensional pictures of brain activity by measuring radioactive isotopes that are injected into the bloodstream. PET scans of the brain are used to detect or highlight tumors and diseased tissue, measure cellular and/or tissue metabolism, show blood flow, evaluate patients who have seizure disorders that do not respond to medical therapy and patients with certain memory disorders and determine brain changes following injury or drug abuse, among other uses. PET may be ordered as a follow-up to a CT or MRI scan to give the physician a greater understanding of specific areas of the brain that may be involved with certain problems. Scans are conducted in a hospital or at a testing facility on an outpatient basis. PET scans are often abnormal in dystonia but are generally performed only as part of research protocols, many of which are done at the Feinstein Institute at North Shore.
• Electroencephalography (EEG) monitors brain activity through the skull. EEG is used to help diagnose certain seizure disorders, brain tumors, brain damage from head injuries, inflammation of the brain and/or spinal cord, alcoholism, certain psychiatric disorders and metabolic and degenerative disorders that affect the brain. EEGs are also used to evaluate sleep disorders, monitor brain activity when a patient has been fully anesthetized or loses consciousness. EEGs are generally normal in dystonia and are not often needed unless seizure activity is suspected.
• Electromyography (EMG) is used to diagnose nerve and muscle dysfunction and spinal cord disease. It records the electrical activity from the brain and/or spinal cord to a peripheral nerve root (found in the arms and legs) that controls muscles during contraction and at rest. EMGs are often normal in dystonia but may sometimes be performed to identify the most overactive muscle groups, especially when treating the overactive muscles with botulinum toxin.
• Electronystagmography (ENG) describes a group of tests used to diagnose involuntary eye movement, dizziness, and balance disorders and to evaluate some brain functions. The test is performed at an imaging center. Small electrodes are taped around the eyes to record eye movements. If infrared photography is used in place of electrodes, the patient wears special goggles that help record the information. Both versions of the test are painless and risk-free. ENG is generally normal in dystonia and is not routinely performed.