Dr. Ajmal Masood Gilani, MD, FAAN

• Visual evoked potential, which tests how the brain reacts to visual stimuli. During the test, electrodes will be applied on the scalp and patients are shown a flashing checkerboard pattern. The electrical signals the patients' brain produces in response to the pattern will be recorded. This test is able to identify issues in the optic nerve and is a helpful tool in diagnosing multiple sclerosis, as optic nerve damage is an early sign of that disease.
• Auditory evoked potential, which measures how the brain responds to sound. In this test, the electrodes will be applied on the earlobes and on the scalp. Different sounds, such as clicks and tones, will be played through headphones, and responses to those sounds will be recorded. Aside from hearing loss in children, this test also diagnoses acoustic neuromas, which are noncancerous tumors in the ear canal that affect hearing and balance.
• Somatosensory evoked potential, which tests how well the brain communicates with the spinal cord and the rest of the body. Faint electrical signals will be sent through electrodes that are applied on the wrist or the back of the knee. Electrodes on the scalp will measure how long it takes for the brain to receive the signals. This evoked potential test is often used to diagnose multiple sclerosis. In addition, since it can identify spinal cord issues, it may also be given to individuals who experience numbness following a spinal injury.
• Motor evoked potential, which measures how the motor pathways function. These pathways deliver signals from the brain and spinal cord to the motor neurons, which are specialized cells directly responsible for controlling muscles. The test uses a device to send magnetic or electrical pulses to any part of the body. Patient response will show if motor neurons can adequately receive signals from the brain and spinal cord. Because this test detects communication issues in the motor pathways, it is used to diagnose multiple sclerosis, as well as to evaluate stroke recovery.

Each test takes between 30 to 60 minutes to complete, and can be done at the doctor's office. Application and removal of the electrodes do not hurt, but since they are placed on the scalp, patients should wash their hair with shampoo and avoid using conditioner or other hair products prior to the test.

There are two main types of stroke: ischemic stroke and hemorrhagic stroke. Ischemic stroke occurs more commonly and is when a blood vessel in the brain becomes blocked. Blockages are caused by blood clots and built-up plaque (deposits of fat and cholesterol), which leads to atherosclerosis, a condition where the blood vessels narrow and harden. The resultant restricted blood flow may lead to an ischemic stroke by blocking essential oxygen to the brain, causing the heart to exert more effort to pump blood.

Hemorrhagic stroke occurs when a blood vessel in or around the brain ruptures. The burst vessel leaks blood into surrounding brain tissue, causing irreparable brain damage.

Hemorrhagic strokes are less common and may occur from head injuries, brain aneurysms, brain tumors, and bleeding disorders, amongst other conditions.

Both ischemic and hemorrhagic strokes require immediate medical treatment. Medical intervention can prevent severe and life-threatening brain damage. Signs of stroke include:

-Disorientation or confusion

-Difficulty speaking

-Difficulty walking

-Impaired vision

-Weakness in the face, legs, or arms

-Severe headaches

When someone suspected of having a stroke reaches the hospital, the patient will usually receive a CT or other scan that provides an image of the brain. The scan results can reveal clotted or leaking blood in the brain. Physical exams, neurological exams, and blood tests may also be used to check for blood clotting and sugar. Treatment begins generally immediately if a stroke is detected.

Medical treatment for ischemic strokes includes a thrombolytic medicine which breaks up and disperses blood clots. This medicine can greatly improve stroke recovery and long-term health. However, the thrombolytic medicine must be administered as soon as possible to achieve these results. Other treatments for ischemic strokes are blood thinners and thrombectomy, a surgical procedure to remove a blood clot in the brain. Thrombectomy is performed by inserting a catheter (thin needle) into the artery to reach the blood clot and mechanically remove it. With the clot removed, normal blood flow to the brain resumes. Thrombectomy is typically performed at most six hours after a patient shows signs of a stroke.

Hemorrhagic strokes are treated with blood-saving medication and surgery. For a hemorrhagic stroke caused by the rupture of an aneurysm (blood vessel bulges), surgery to stem the bleeding aneurysm and vessel may be used. One surgical technique is stent-assisted coiling, which adds a stent (small wire-meshed tube) into the blood vessel to block the leaking opening of the aneurysm. A non-surgical procedure is endovascular coiling, where a catheter (thin, hollow needle) places a platinum wire coil at the spot of the aneurysm. The coil blocks bleeding and prevents the aneurysm from continuing to leak blood. These procedures are usually combined with blood-thickening medications. Blood transfusions may be administered if substantial blood loss has occurred.

Since stroke patients may have lost some essential functions while the blood flow to their brains was obstructed, both ischemic stroke and hemorrhage stroke patients may receive post-stroke rehabilitation to rebuild their physical and mental abilities. Some restorative treatments include occupational, physical, and speech therapy. Patients may also receive care from neurologists, who can assist patients in recovering certain brain functions and cognitive abilities, and rehabilitation psychologists, who may help patients with their emotional, behavioral, and cognitive recovery. Some stroke patients require lengthy rehabilitation and may never fully regain function, while others may recover more quickly. While the fastest recovery improvements are usually seen in the first three or four months, stroke rehabilitation can last for years.

If someone begins to show signs of stroke, contact emergency services and call 9-1-1 immediately since blood flow must be restored as soon as possible to help avoid significant brain damage. If an ambulance takes the person to the hospital, paramedics can initiate stroke treatment as soon as the patient enters the ambulance, allowing for more prompt medical intervention and care.