Brain disorders

• Because the brain controls almost all of the functions of the human body, injury to the brain can affect many different parts of the body. Brain disorders, which may be inherited or caused by infections, and head injuries can affect the way the brain works and upset the daily activities of the rest of the body.
• The nervous system is the body's communication center. The central nervous system (CNS) includes the brain and the spinal cord while the peripheral nervous system (PNS) is composed of nerves. Together, the CNS and PNS control every function of the body, from breathing and blinking to memorizing facts for a test. Nerves from the spinal cord branch outward to the rest of the body. Sensory nerves gather information from the environment and send that information to the spinal cord, which then speeds the message to the brain. The brain makes sense of that message and fires off a response. Motor neurons deliver instructions from the brain to the rest of the body.
• The brain is composed of three main parts: the forebrain, midbrain, and hindbrain. The forebrain consists of the cerebrum, thalamus, and hypothalamus (part of the limbic system). The midbrain consists of the tectum and tegmentum. The hindbrain is composed of the cerebellum, pons, and medulla.
• The cerebrum or cerebral cortex is the largest part of the human brain. The cerebrum is associated with higher brain function, such as thought and memory. The cerebral cortex is divided into four sections, including the frontal lobe, parietal lobe, occipital lobe, and temporal lobe.
• The frontal lobe is associated with reasoning, planning, parts of speech, movement, emotions, and problem solving. The parietal lobe is associated with movement, orientation, recognition, and perception of stimuli. The occipital lobe is associated with visual processing. The temporal lobe is associated with perception, memory, speech, and recognition of auditory stimuli.
• A deep furrow divides the cerebrum into two halves, the left and right hemispheres. The corpus callosum is a bundle of axons that connects these two hemispheres. The two hemispheres look symmetrical but are proven to function slightly differently. The right hemisphere is associated with creativity while the left hemisphere is associated with logic abilities.
• Nerve cells make up the gray surface of the cerebrum. White nerve fibers underneath carry signals between the nerve cells and other parts of the brain and body.
• The neocortex occupies the bulk of the cerebrum. This is a six-layered structure of the cerebral cortex that is only found in mammals. It is believed that the neocortex is a recently evolved structure and that it is associated with "higher" information processing among more evolved animals (such as humans and other primates).
• The cerebellum, or "little brain," is similar to the cerebrum in that it has two hemispheres and a highly folded surface or cortex. This structure is associated with regulation and coordination of movement, posture, and balance.
• The limbic system, often referred to as the "emotional brain," is found buried within the cerebrum. The lymbic system contains the thalamus, hypothalamus, amygdala, and hippocampus.
• Underneath the limbic system is the brain stem. The brain stem is composed of the midbrain, pons, and medulla. This structure is responsible for basic vital functions such as breathing, heartbeat, and maintenance of blood pressure. Scientists describe the brain stem as the "simplest" part of the human brain. In some animals that appeared early on the evolutionary scale (such as reptiles), the entire brain resembles a human brain stem.
• Disorders of the brain can occur as the result of infection, such as meningitis and encephalitis, or traumatic head injury, such as a concussion or contusion.

• Meningitis: In children, the symptoms of meningitis vary and depend on both the age of the child and the cause of the infection. Because the flu-like symptoms can be similar in both types of meningitis, particularly in the early stages, and bacterial meningitis can be very serious, it is important to quickly diagnose an infection.
• The first symptoms of bacterial or viral meningitis can occur within days after a child has had a cold and runny nose, diarrhea and vomiting, or other signs of an infection. Other common symptoms include fever, lethargy (decreased consciousness), irritability, headache, photophobia (eye sensitivity to light), stiff neck, skin rashes, and seizures.
• Infants with meningitis may not have the symptoms described above and might simply be extremely irritable or lethargic or have a fever. They may be difficult to comfort, even when picked up and rocked. Other symptoms of meningitis in infants can include jaundice (a yellowish tint to the skin), stiffness of the body and neck (neck rigidity), fever or lower-than-normal body temperature, poor feeding, a weak suck, a high-pitched cry, or bulging fontanelles (the soft spot at the top/front of the baby's skull).
• Viral meningitis tends to cause flu-like symptoms, such as fever and runny nose, and may be so mild that the illness goes undiagnosed. Most cases of viral meningitis resolve completely within 7-10 days without any complications or need for treatment.
• Most cases of meningitis, both viral and bacterial, result from infections that are contagious. Contagious viruses and bacteria are spread via tiny drops of fluid from the throat and nose of someone who is infected. The drops may become airborne when the person coughs, laughs, talks, or sneezes. They then can infect others when breathed in or if others touch the drops and then touch their own noses or mouths. Sharing food, drinking glasses, eating utensils, tissues, or towels all can transmit infection as well. Some infectious organisms can spread through an individual's stool, and someone who comes in contact with the stool (such as a child in day care) may contract the infection.
• Infection is most often spread between people who are in close contact. Casual contact at school or work with an infected individual usually will not transmit the infectious agent.
• Encephalitis: Encephalitis may cause fever, headache, poor appetite, loss of energy, or a generally ill feeling. In more severe cases, other symptoms might occur including: high fever; severe headache; photophobia (sensitivity to light); nausea and vomiting; stiff neck; confusion; sleepiness, difficulty waking or unconsciousness; or convulsions (seizures).
• When encephalitis follows a common illness like chickenpox (Varicella zoster), the signs and symptoms of that illness usually precede symptoms of inflammation in the brain. However, encephalitis can also appear without warning. If symptoms of encephalitis are present, it is important to contact a doctor immediately.
• Traumatic brain injury (TBI): Some symptoms of traumatic brain injury (TBI) are evident immediately, while others are not evident until several days or weeks after the injury.
• With mild TBI, the individual may remain conscious or may lose consciousness for a few seconds or minutes. The individual may also feel dazed or confused for several days or weeks after the initial injury. Other symptoms include headache; mental confusion; lightheadedness; dizziness; double vision, blurred vision, or tired eyes; ringing in the ears; bad taste in the mouth; fatigue or lethargy; a change in sleep patterns; behavioral or mood changes; or trouble with memory, concentration, or calculation. Symptoms may remain the same or get better; worsening symptoms indicate a more severe injury.
• With moderate or severe TBI, the individual may show these same symptoms, but may also have loss of consciousness; personality change; a severe, persistent, or worsening headache; repeated vomiting or nausea; seizures; inability to awaken; dilation (widening) of one or both pupils; slurred speech; weakness or numbness in the extremities; loss of coordination; or increased confusion, restlessness, or agitation. The coexistence of vomiting and neurological problems (such as weakness in a limb) is an important indicator that the condition is worsening.
• Small children with moderate to severe TBI may show some of these signs as well as signs specific to this population, including persistent crying, inability to be consoled, or refusal to nurse or eat.
• Anyone with signs of moderate or severe TBI should receive immediate emergency medical attention.

• Meningitis and encephalitis
  :
• For both meningitis and encephalitis, diagnosis can be made by withdrawing a small sample of spinal fluid for examination during a procedure called a lumbar puncture (spinal tap). A spinal tap is usually done in a hospital or clinical setting and involves inserting a needle into the middle of the lower back and collecting some drops of fluid. The procedure can be slightly uncomfortable but is rarely painful with the use of a local anesthetic. The entire procedure usually takes about 45 minutes. Once the procedure is complete, the individual will need to lie flat for 20 minutes to one hour.
• Laboratory analysis of the spinal fluid will confirm whether the meninges are infected as well as what bacteria or virus may be causing the infection.
• To test for the presence of suspected bacteria or viruses in newborns, doctors may check stomach fluids with a small tube passed down the throat. The infant's feces may also be checked for the presence of bacteria or viruses.
• Polymerase chain reaction analysis: If meningitis is suspected, a DNA-based test known as a polymerase chain reaction (PCR) can be ordered to check for the presence of bacteria or viruses that may cause meningitis or encephalitis.
• Brain imaging: A computerized tomography (CT) or magnetic resonance imaging (MRI) scan may reveal swelling of the brain that may occur in encephalitis or meningitis.
• Electroencephalography (EEG): An electroencephalography (EEG) procedure measures the waves of electrical activity produced by the brain. An EEG is often used to diagnose and manage seizure disorders. A number of small electrodes are attached to the scalp. The electrodes pick up the electrical impulses from the brain and send them to an instrument that records the brain waves. An abnormal EEG result may suggest encephalitis, but a normal result does not rule out the disease.
• Traumatic brain injury
  :
• Neurological examination: If a traumatic brain injury (TBI) is suspected, a complete neurological evaluation is performed to rule out conditions requiring neurosurgical attention, such as hematomas (blood clots), depressed skull fractures, and elevated intracranial pressure (ICP). X-rays, CT scans, and/or MRI scans may be performed to determine if the bones of the skull are fractured and if bone fragments have penetrated the brain tissue.
• Alertness and orientation of the individual will be assessed. The individual may be presented with a series of questions to determine if he or she can open their eyes, move, speak, and understand what is happening around them. If possible, a detailed medical history is obtained to identify any previous injuries, existing seizure disorders, learning disabilities, prior psychiatric or psychological treatment, and/or substance abuse.
• The individual's degree of consciousness is assessed to determine the severity of brain injury and predict the chances for recovery. Doctors typically use the Glasgow Coma Scale (GCS), which measures the individual's ability to speak, move, and open his or her eyes. The more severe the injury, the lower the total score, suggesting little chance for complete recovery. The longer the length of a coma, the more severe the injury.
• The neurological examination may uncover signs of the severity of injury such as increased reflexes and muscle tone (spasticity), abnormal movements (tremors), difficulty swallowing, or slurring of speech, all of which may indicate a moderate to severe head injury.
• Imaging: Imaging tests using computer-assisted brain scans help visualize damage to the brain. The most common of these is the computerized tomography (CT) scan, a two-dimensional X-ray technique that produces cross-sectional images of the brain. CT scans can detect physical changes in the brain such as hematomas and swelling, which may require immediate treatment. The procedure is painless and takes 15-45 minutes, during which the patient must lie completely still.
• Another useful diagnostic test is magnetic resonance imaging (MRI scan), which uses a large magnet and radio waves to generate computerized images of the brain without exposing the patient to X-ray radiation. MRIs produce high resolution images of brain structures and are painless. The patient must lie on a flat table in the machine, typically shaped like a long tube. An MRI can take up to 60 minutes. If the individual is sensitive to enclosed places, a mild sedative such as lorazepam (Ativan®) may be used. Open-sided MRIs are now available that decrease problems with closed spaces.
• An angiogram is a test used to examine blood vessels in the brain. Performing an angiogram involves injecting dye into an artery supplying blood to the brain by means of a catheter inserted into an artery, typically in the groin or forearm. The individual may not be allowed to eat and drink for four to six hours before the test. Before the test, the individual may be given a mild sedative. The radiologist will use a local anesthetic (such as lidocaine) at the injection site so that no pain will be felt. The radiologist will then put a very small tube (catheter) into the blood vessels in the selected artery. This catheter is passed through the other blood vessels in the body until it reaches the neck. The radiologist will then position the tube into different blood vessels in the neck. During this time, injections of a special dye known as a contrast agent are given that help to give more detail on the pictures. The injection may give the individual a general warm feeling that goes away quickly. Before the pictures are taken, the radiographer will move the equipment around the individual into the correct position; pictures are taken during further injections. Problems with the blood vessels of the brain can be seen on the X-ray. When all the required information has been collected, the tube in the artery will be removed by the radiologist. The point where the tube was inserted will be pressed on for up to ten minutes to seal it and stop any bleeding. The test takes one to three hours.
• An intracranial pressure (ICP) monitor is a device used to measure the pressure that is exerted on the brain. To measure ICP, a small tube is placed into or on top of the brain through a small hole in the skull and connected to a transducer that registers the pressure. ICP increases in response to injury or infection involving the brain.

• The complications of meningitis and encephalitis can be severe, and often require immediate medical attention. Without immediate treatment, permanent neurological damage may result, including hearing loss, blindness, loss of speech, learning disabilities, behavior problems, brain damage, and paralysis.
• Non-neurological complications may include kidney failure and adrenal gland failure. The adrenal glands produce a number of important hormones including cortisol, the stress hormone. Higher and more prolonged levels of cortisol in the bloodstream (like those associated with chronic stress) have been shown to have negative effects, such as impaired cognitive performance, suppressed thyroid function, blood sugar imbalances, decreased bone density, decreased muscle tissue, increased blood pressure, lowered immunity and inflammatory responses in the body, and increased abdominal fat.
• Bacterial infections of the central nervous system progress quickly. Within a matter of days, the disease can lead to shock and death.
• Disabilities resulting from a traumatic brain injury (TBI) depend upon the severity and location of the injury, as well as the age and general health of the individual. Some common disabilities include problems with cognition (thinking, memory, and reasoning), sensory processing (sight, hearing, touch, taste, and smell), communication (expression and understanding), and behavior or mental health (depression, anxiety, personality changes, aggression, acting out, and social inappropriateness).
• Head injuries may result in an unresponsive state in which an individual can only be aroused briefly by a strong stimulus, such as sharp pain. More serious head injuries may result in a coma, a state in which an individual is totally unconscious, unresponsive, unaware, and unable to be aroused. Severe brain injuries may also result in a vegetative state or persistent vegetative state. A vegetative state is a coma in which an individual is unconscious and unaware of his or her surroundings, but continues to have a sleep-wake cycle and periods of alertness. A persistent vegetative state (PVS) is a coma in which an individual stays in a vegetative state for more than a month.

• Meningitis: Treatment for meningitis depends on the organism causing the infection, the individual's age, the extent of the infection, and the presence of other medical conditions or complications of meningitis, such as seizures.
• Most people with viral meningitis start to improve within three days of feeling ill and recover fully within two weeks. However, it is important to seek medical attention if symptoms of meningitis develop so that bacterial meningitis, which is more serious, can be ruled out. With mild cases of viral meningitis, the individual may only need treatments for pain and dehydration, such as acetaminophen (Tylenol®) to control pain and fever. If the individual does not improve or if symptoms worsen, further testing may be needed to check for other causes of illness.
• Prescription antibiotics are usually given through a vein (intravenously or IV) to treat meningitis. Antibiotics are given only when bacteria are causing the infection.
• If meningitis is causing increased intracranial pressure (ICP), corticosteroid medicines, such as dexamethasone (Decadron®), may be given to relieve the pressure.
• If seizures occur, the individual's surroundings should be kept quiet and calm. Medicines such as phenobarbital or dilantin (Phenytoin®) can help stop the seizures.
• Oxygen may be given to assist breathing and to increase the amount of oxygen in all parts of the body. Oxygen may be delivered through a hood or tent placed over the body, a face mask placed over the nose and mouth, a nose piece (nasal cannula) held loosely under the nose, or, in severe cases, a tube through the mouth into the trachea (windpipe).
• The individual may need to drink extra liquids because infections increase the body's need for fluids. Increasing liquids also reduces the possibility of dehydration. Liquids are given through a vein (intravenously or IV) if infection is present, if the patient is vomiting, or if the patient is unable to consume sufficient liquids orally.
• Encephalitis: Choice of treatment for encephalitis will depend on the cause. Bacterial encephalitis is treated with antibiotics. Viral encephalitis is usually treated with antiviral drugs including acyclovir (Zovirax®), ganciclovir (Cymevene®), foscarnet (Foscavir®), ribovarin (Virazole®), and AZT (Retrovir®).
• The symptoms of encephalitis may be treated with a number of different drugs. Corticosteroids, including prednisone (Deltasone®) and dexamethasone (Decadron®), are sometimes prescribed to reduce inflammation and brain swelling. Anticonvulsant drugs, including dilantin (Phenytoin®), are used to control seizures. Fever may be reduced with acetaminophen (Tylenol®) or other fever-reducing drugs.
• Herpes encephalitis can cause rapid death if not diagnosed and treated promptly. Medication is usually started immediately when the doctor suspects herpes without waiting for confirmatory results. The recommended treatment is acyclovir (Zovirax®) given intravenously (IV or into the veins) for two to three weeks. Acyclovir-resistant herpes encephalitis can be treated with foscarnet (Foscavir®). Liver and kidney functions should be monitored throughout the course of medication.
• The most severe symptoms of encephalitis, such as seizures, generally last up to one week, but full recovery may take weeks or longer.
• Traumatic brain injury (TBI): Call 911. Anyone with signs of moderate or severe traumatic brain injury (TBI) should receive medical attention as soon as possible. Because little can be done to reverse the initial brain damage caused by trauma, medical personnel try to stabilize an individual with TBI and focus on preventing further injury. Primary concerns include insuring proper oxygen supply to the brain and the rest of the body, maintaining adequate blood flow, and controlling blood pressure. Imaging tests help in determining the diagnosis and prognosis of a TBI patient. Those with mild to moderate injuries may receive skull and neck X-rays to rule out bone fractures or spinal instability. For moderate to severe cases, the imaging test is a computed tomography (CT) scan.
• Moderately to severely injured patients receive rehabilitation that involves individually tailored treatment programs comprising physical therapy, occupational therapy, speech/language therapy, physical medicine, psychology/psychiatry, and social support.
• Approximately half of patients with severe head injuries will require surgery to remove or repair hematomas (blood clots) or contusions (bruised brain tissue).
• Medical attention for a brain injury is necessary if an individual becomes unusually drowsy, develops a severe headache or stiff neck, vomits more than once, loses consciousness (even if only briefly), or behaves abnormally.
• For a moderate to severe head injury, healthcare professionals recommend calling 911.
• For a mild head injury, no specific treatment may be needed. However, healthcare professionals recommend close supervision of the individual for any concerning symptoms over the next 24 hours. The symptoms of a serious head injury can be delayed. While the person is sleeping, it is important to wake him or her every two to three hours and ask simple questions to check alertness, such as "What is your name?"
• If a child begins to play or run immediately after getting a bump on the head, serious injury is unlikely. However, as with anyone with a head injury, watch the child closely for 24 hours after the incident.
• Over-the-counter pain medicine, such as acetaminophen (Tylenol®) or ibuprofen (Advil®), may be used for a mild headache. Aspirin may increase the risk of bleeding and is not recommended by healthcare professionals for use in TBI.

B

Good scientific evidence

• Ginkgo
  : Multiple clinical trials have evaluated ginkgo for a syndrome called cerebral insufficiency. This condition, more commonly diagnosed in Europe than the United States, may include poor concentration, confusion, absent-mindedness, decreased physical performance, fatigue, headache, dizziness, depression, and anxiety. It is believed that cerebral insufficiency is caused by decreased blood flow to the brain due to clogged blood vessels. Some studies report benefits of ginkgo in patients with these symptoms, but most have been poorly designed without reliable results. Better studies are needed before a conclusion can be made.
• Avoid if allergic or hypersensitive to members of the Ginkgoaceae
  family.
  If allergic to mango rind, sumac, poison ivy or oak or cashews, then allergy to ginkgo is possible. Avoid with blood-thinners (like aspirin or warfarin (Coumadin®)) due to an increased risk of bleeding. Ginkgo should be stopped two weeks before surgical procedures. Ginkgo seeds are dangerous and should be avoided. Skin irritation and itching may also occur due to ginkgo allergies. Ginkgo should not be used in supplemental doses if pregnant or breastfeeding.

C

Unclear or conflicting scientific evidence

• Ayurveda
  : Early evidence suggests that the aqueous extract of O. sanctum leaves may benefit patients with viral encephalitis. However, human studies are needed to evaluate this approach.
• Ayurvedic herbs should be used cautiously. Some herbs imported from India have been reported to contain high levels of toxic metals. Ayurvedic herbs can interact with other herbs, foods, and drugs. A qualified healthcare professional should be consulted before taking. Use guggul cautiously with peptic ulcer disease. Avoid sour food, alcohol, and heavy exercise with use of ayurvedic herbs. Mahayograj guggul should not be taken for long periods of time. Pippali (Piper longum) should be taken with milk and avoided with asthma. Avoid sweet flag, and avoid amlaki (Emblica officinalis) at bedtime. Avoid Terminalia hebula (harda) if pregnant. Avoid Ayurveda with traumatic injuries, acute pain, advanced disease stages and medical conditions that require surgery.
• Bupleurum
  : Bupleurum (Bupleurum falcatum, Bupleurum fruticescens) has been widely used as a medicinal herb for more than 2,000 years in Asia. An herbal combination formula containing bupleurum has been used as a treatment for minimal brain dysfunction in children. Early study is inconclusive, and additional study is needed to make a firm recommendation.
• Reported side effects include decreased appetite, nausea, reflux, abdominal distension, intestinal gas, and increased bowel movements following large doses of bupleurum. Avoid if allergic or hypersensitive to bupleurum, members of the Apiaceae or Umbelliferae (carrot) families, snakeroot, cow parsnip, or poison hemlock. Use cautiously if operating motor vehicles or hazardous machinery. Use cautiously with low blood pressure, diabetes, or edema. Use cautiously with a history of bleeding, hemostatic disorders, or drug-related hemostatic disorders. Use cautiously if taking blood thinners. Avoid if pregnant or breastfeeding.
• Choline
  : Early treatment with choline alphoscerate (CA), a substrate of phosphatidylcholine and a carrier of choline, has been studied for use in craniocerebral brain injuries. When taken as part of complex pharmacotherapy, it has shown beneficial effects. Currently, there is a lack of sufficient evidence to recommend for or against the use of choline in coma patients. Available research is limited.
• Avoid if allergic/hypersensitive to choline, lecithin, or phosphatidylcholine. Use cautiously with kidney or liver disorders or trimethylaminuria. Use cautiously with a history of depression. If pregnant or breastfeeding it seems generally safe to consume choline within the recommended adequate intake (AI) parameters; supplementation outside of dietary intake is usually not necessary if a healthy diet is consumed.
• DMSO (dimethyl sulfoxide)
  : DMSO may help treat intracranial pressure in the skull, but most research is vague and results are conflicting. The risks may be greater than potential benefits.
• Avoid if allergic or hypersensitive to DMSO. Use caution with urinary tract cancer or liver and kidney dysfunction. Avoid if pregnant or breastfeeding.
• Garlic
  : Preliminary study documented potential benefits of oral plus intravenous garlic in the management of cryptococcal meningitis. Further research is needed before recommending for or against the use of garlic in the treatment of this potentially serious condition, for which other treatments are available.
• Caution is advised when taking garlic supplements, as adverse effects including an increase in bleeding and drug interactions are possible. Garlic supplements should not be used if pregnant or breastfeeding, unless otherwise directed by a doctor.
• Ginseng
  : Preliminary study of Xuesaitong injection (XSTI, a preparation of Panax notoginseng) reports that it may help to decrease intracranial pressure. Further research is needed to confirm these results.
• Avoid ginseng with known allergy to plants in the Araliaceae family. There has been a report of a serious life-threatening skin reaction, possibly caused by contaminants in ginseng formulations.
• Peppermint
  : Peppermint (Mentha piperita) is a flowering plant that grows throughout Europe and North America. Peppermint is widely cultivated for its fragrant oil. There is currently a lack of sufficient evidence to recommend for or against the use of peppermint oil aromatherapy for vigilance improvement following brain injury.
• Peppermint oil should be used cautiously because doses of the constituent menthol greater than one gram per kilogram of body weight may be fatal. Avoid if allergic or hypersensitive to peppermint or menthol. Use cautiously with G6PD deficiency or gallbladder disease. Avoid if pregnant or breastfeeding.
• Policosanol
  : The effects of policosanol supplementation on reactivity and related brain activity have been examined. Although there is early compelling evidence, further research is necessary before a clear conclusion can be made.
• Avoid if allergic or hypersensitive to policosanol. Use cautiously if taking aspirin or blood pressure medications. Use cautiously with high blood pressure. Use cautiously if pregnant or breastfeeding.
• Riboflavin
  : Riboflavin (vitamin B2) is a water-soluble vitamin, which is involved in vital metabolic processes in the body, and is necessary for normal cell function, growth, and energy production. Small amounts of riboflavin are present in most animal and plant tissues. Although the exact pathogenesis of ethylmalonic encephalopathy is unknown, some research suggests that riboflavin may lead to slight improvements in motor function, cognitive behavior, and diarrhea.
• Avoid if allergic or hypersensitive to riboflavin. Since the amount of riboflavin a human can absorb is limited, riboflavin is generally considered safe. Riboflavin is generally regarded as safe during pregnancy and breastfeeding. The U.S. Recommended Daily Allowance (RDA) for riboflavin in pregnant women is higher than for non-pregnant women, and is 1.4 milligrams daily (1.6 milligrams for breastfeeding women).
• Selenium
  : Preliminary research shows a decrease of elevated intracranial pressure symptoms (headaches, nausea, vomiting, vertigo, unsteady walk, speech disorders and seizures) with use of selenium. More research is needed before a firm conclusion can be made.
• Avoid if allergic or sensitive to products containing selenium. Avoid with history of non-melanoma skin cancer. Selenium is generally regarded as safe for pregnant or breastfeeding women. However, animal research reports that large doses of selenium may lead to birth defects.
• Tai chi
  : Tai chi is a system of movements and positions believed to have developed in 12th Century China. Tai chi techniques aim to address the body and mind as an interconnected system, and are traditionally believed to have mental and physical health benefits to improve posture, balance, flexibility, and strength. Based on limited available study, tai chi may provide short-term benefits after traumatic brain injury; however, long-term studies are needed.
• Avoid with severe osteoporosis or joint problems, acute back pain, sprains, or fractures. Avoid during active infections, right after a meal, or when very tired. Some believe that visualization of energy flow below the waist during menstruation may increase menstrual bleeding. Straining downwards or holding low postures should be avoided during pregnancy, and by people with inguinal hernias. Some tai chi practitioners believe that practicing for too long or using too much intention may direct the flow of chi (qi) inappropriately, possibly resulting in physical or emotional illness. Tai chi should not be used as a substitute for more proven therapies for potentially serious conditions. Advancing too quickly while studying tai chi may increase the risk of injury.
• Thymus extract
  : Preliminary evidence suggests that thymus extract has no clinical effect in patients with subacute sclerosing panencephalitis. Additional study is needed to better determine the potential role of thymus extract in encephalitis.
• Avoid if allergic or hypersensitive to thymus extracts. Use bovine thymus extract supplements cautiously due to potential for exposure to the virus that causes "mad cow disease." Avoid use with an organ transplant or other forms of allografts or xenografts. Avoid if receiving immunosuppressive therapy or hormone therapy. Avoid with thymic tumors, myasthenia gravis (neuromuscular disorder) or untreated hypothyroidism. Avoid if pregnant or breastfeeding. Thymic extract increases human sperm motility and progression.
• zinc
  : Early poorly designed studies indicate that zinc supplementation may enhance neurological recovery in patients with closed head injuries. Further research is needed to confirm these results.
• Zinc is generally considered safe when taken at the recommended dosages. Avoid zinc chloride since studies have not been done on its safety or effectiveness. Avoid with kidney disease. Use cautiously if pregnant or breastfeeding.

D

Fair negative scientific evidence

• Magnesium
  : There may be evidence to support the use of magnesium salts in patients with acute traumatic brain injury. Magnesium has also been studied for subarachnoid hemorrhage in combination with other agents, with inconclusive results.
• Use cautiously in patients with bleeding disorders, or in those taking anticoagulants or antiplatelet agents. Use cautiously in patients taking antidiabetic, antihypertensive, or antibiotic agents. Use intravenous magnesium sulfate with extreme caution in patients with eclampsia. Avoid in patients with atrioventricular heart block. Avoid in patients with renal failure or severe renal disease. Avoid use as a laxative in patients with gastrointestinal disorders. Avoid intravenous magnesium in women with toxemia during the first few hours of labor.