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Cognitive Function

Introduction

What should I know about Cognitive Function?

Cognitive function is the term used to describe a person’s state of consciousness (alertness and orientation), memory, and attention span. A mental status examination (MSE) is a standard test used by healthcare professionals to measure a patient’s overall mental health. Evaluating a patient’s cognitive function includes, first of all, measuring their level of alertness and orientation.

Awareness and thinking depend on organized thoughts, personal experiences, emotions, and mental processes, each existing in a special region of the brain. Self-awareness requires sensing this personal stream of thought and emotional experiences. When a person cannot maintain a logical sequence of thoughts, and when this goes along with not being able to pay attention and being disoriented, this describes confusion. (1)

Alertness measures a patient’s awareness of his or her environment and situation. Abnormal states range from confusion to lethargy (tiredness), delirium (confusion), stupor (daze), or even coma. Orientation is a person’s ability to describe their knowledge of person, place, and time. Asking simple questions such as the patient’s name, where they live, the current date or day of the week, or season of the year can be used to evaluate orientation. Disorientation is very often linked with organic brain syndromes (for example, dementia). (2)

Confusion describes a behavior where there is decreased mental clearness, consistency, understanding, and being able to reason. (3) Lack of attention and disorientation are the main early signs; however, as the confusion gets worse, there is a decrease of memory, awareness, understanding, problem solving, language, actions, functioning in one’s environment, and emotional behavior.

Changes in a person’s state of consciousness, such as with confusion, lethargy, and delirium, may be caused by many medical conditions including fever, ischemia (decreased blood supply), trauma, or brain diseases. It may also be caused by some drugs or toxins. Other causes are hypoglycemia (low blood sugar), azotemia (nitrogen waste products in the blood), liver failure, hypercalcemia (increased calcium in the blood), or a lesion that can develop at the base of the brain.

Memory is a person’s ability to remember information in the past and the present. Memory is considered the most common and the most important cognitive ability that can be lost. Healthcare professionals may test a patient’s memory by asking questions about the history of their present illness or what they had to eat at a recent meal. They may ask a patient to remember three different words, such as a color, a person’s address, and an object, then later in the interview, ask if the patient can remember what they were just asked. These are tests of present or short-term memory. Questions concerning family history, date of birth, and facts from a person’s past test a patient’s past (distant) memory. Delirium, dementias, amnesia, Korsakoff’s psychosis, and anxiety are conditions associated with an impaired memory. (4)

Dementias are disorders with symptoms of memory loss and a decrease in cognition and the ability to reason. (5) Dementia, sometimes called "senility," is not a part of the normal aging process, and shows that some other disease may be present. Dementia affects a person's ability to be successful in carrying out their activities of daily living. (6) Accurate diagnosis of the disease that is present is necessary for treating the dementia properly.

The healthcare professional also measures attention span and the ability to concentrate in evaluating cognitive function. They ask the patient to solve a short series of problems such as subtracting seven from 100 in sequence (100, 93, 86, 79, and so on). The healthcare professional may also want to test higher levels of intelligence. These tests evaluate the patient’s use of language, the amount of knowledge that they have, their abstract reasoning, and their ability to make decisions.

The Diagnostic and Statistical Manual of Mental Disorders, fourth edition, (DSM-IV) is a book that provides a common language for mental health care practitioners to describe psychiatric disorders. (7) The book also helps the healthcare provider to diagnose the mental illness. Sometimes the Mini-Mental Status Examination (MMSE) is used, which is a 30-point set of test questions to measure cognitive function.

Alzheimer’s disease is the most common cause of dementia, accounting for over 60 percent of all cases. (8) Loss of memory is the typical complaint of the Alzheimer’s patient. Minor memory loss, sometimes called age-associated memory impairment, is a common complaint of normal aging and should not cause concern. However, if this minor memory loss affects social or job functions, or is noticed by friends and coworkers, patients should be encouraged to visit a healthcare professional to be evaluated. (9) Loss of memory in patients with Alzheimer’s disease usually includes a problem remembering and using information already learned and experienced. Patients are usually upset by not being able to remember recent events, or with their confusion about time.

Other causes of decreased cognitive function with dementias, happen because of a lack of proper nutrition in the diet. (10) A lack of thiamine (vitamin B1) is known to cause Wernicke’s encephalopathy (a condition of memory loss and other symptoms due to vitamin B1 loss from alcoholism). Such a patient has malnutrition, confusion, ataxia (loss of muscle coordination), and diplopia (double vision). A severe lack of vitamin B12, folic acid, or omega 3 fatty acids may cause dementia due to damage to nerve fibers in the brain. A lack of vitamin B3 (niacin), which causes the disease pellagra, and vitamin B6 (pyridoxine) may cause spastic paraparesis (a type of paralysis), peripheral neuropathy (a condition affecting the nervous system), fatigue, irritability, and dementia. This syndrome has been seen in prisoner-of-war (POW) camps.

Toxic substances known to produce dementias include an overdose of narcotic drugs, heavy metals, dialysis dementia (from aluminum), and other organic toxins. Dementias that happen because of a lack of certain vitamins or dementias that happen from poisonings can usually be treated.

Signs and Symptoms

The following list does not insure the presence of this health condition. Please see the text and your healthcare professional for more information.

In the early stages, patients may seem inattentive or disoriented. Patients that become confused are generally subdued, not inclined to speak, and physically inactive. As the disease progresses, patients have increasing difficulty with memory, perception, comprehension, problem solving skills, language skills, and occasional inappropriate emotional behavior. In the final stages of dementia producing illnesses, the patient may lose the ability to coordinate muscle movement for walking, control the bowel or bladder, and may lose the ability to chew or swallow.

It is important to know that there is a difference between the normal aging process, and dementia (loss of functions such as those described above). In normal aging, the loss of memory is slow and involves things like forgetting where objects are located, or forgetting a person’s name or phone number. In dementia causing illnesses such as Alzheimer’s disease, the process continually worsens until the patient is unable to perform normal activities of daily living. It is wise to talk to a doctor if you are unsure whether symptoms are due to aging, or due to another cause.

General

  • Memory problems including difficulty remembering recent events, people, places, times, and dates
  • Difficulty understanding instructions, or being able to complete a task
  • Difficulty understanding the results of actions or making judgments
  • Becomes easily lost, even in familiar surroundings
  • Loss of ability to use the correct word in naming objects
  • May behave strangely, overreacting to certain events, or having very little emotion or reaction
  • Loss of interest in keeping clean and good grooming habits
  • Unable to figure out how to get dressed properly

Treatment Options

Conventional

There are two primary goals for the treatment of decreased cognitive function or dementia. The first goal is to correct any other disease that may be causing the problem. The second is to support and comfort the patient and caregivers.

Treatment of other diseases may include thyroid replacement in the hypothyroid patient, vitamin therapy for decreased thiamine and B12, antibiotics for infections, correcting hydrocephalus (water on the brain), and surgery, radiation, and/or chemotherapy for malignant brain tumors. (11) Stopping the use of drugs that cause sedation (sleepiness) or that affect cognitive function may also help.

Patients with dementias are often depressed. The antidepressant drugs most often recommended that are low in cognitive side effects are selective serotonin reuptake inhibitors (SSRIs), like paroxetine and fluvoxamine, and the tricyclic antidepressants like desipramine and nortriptyline. Medications that can decrease agitation and insomnia without making the dementia worse are low-dose haloperidol, trazodone, buspirone, and propranolol.

The importance of non-drug behavior therapy is also important. The goal is to make the patient’s life as simple, safe, and comfortable as possible.

Nutritional Suplementation


Vitamin C

Vitamin C is an antioxidant that decreases free radical damage in the body. Several studies with elderly people report that individuals who take higher amounts of vitamin C have better cognitive function. (12) , (13) , (14) The results of one study report that vitamin C may protect elderly individuals against atherogenesis (the development of plaque in the blood vessels which can lead to atherosclerosis). (15)


Vitamin E

Vitamin E is another antioxidant vitamin that may protect against the development of dementia and poor cognitive function. (16) Part of this effect is probably due to the role that vitamin E plays in protecting against free radical damage to the vascular system (blood vessels).

A study of the use of vitamin E in patients with Alzheimer’s disease reported that vitamin E may slow the decrease in cognitive function that can eventually lead to placing the Alzheimer’s patient in a nursing home. (17) A new study is planned that will look at whether vitamin E can slow down or prevent Alzheimer disease in elderly persons who have a mild decrease in cognitive function.


Vitamin B12

Decreased cognitive function may be due to decreased vitamin B12. This is a greater problem in elderly individuals since decreased vitamin B12 levels happen more often as a person gets older. This shows the importance of checking elderly individuals for vitamin B12 deficiency. The use of vitamin B12 supplements in elderly individuals with mild mental changes may result in improved cognitive function and help slow down the beginnings of dementia that cannot be treated with much success at this time. (18)


Acetyl-L-Carnitine (ALC)

Acetyl-L-Carnitine is a nutritional product similar to acetylcholine. (19) It may provide protection against decreasing brain function, and also shows promise in the treatment of Alzheimer’s disease due to its ability to increase the production of more acetylcholine in the body. (20) Research scientists think that acetyl-L-carnitine may improve the function of cells in the brain. (21)


Phosphatidylserine

Phosphatidylserine has been used to treat loss of memory and cognitive function in individuals with mild to moderate faulty memory due to age. Phosphatidylserine is reported to maintain the structure and functioning of brain cells. Studies have reported phosphatidylserine being able to improve memory, learning, concentration, word recall, and mood in middle-aged and elderly persons with dementia or decreased cognitive function due to their age. (22) , (23) , (24)


Docosahexaenoic Acid (DHA)

DHA is an omega-3 fatty acid that is necessary for proper growth and development of the brain in infants. DHA is also needed for normal brain function in adults. Including DHA in the diet has been reported to improve learning. In adults, decreases in DHA in the brain are reported to cause decreased cognitive function during aging. (25) In Japan and European countries, DHA is being added to infant formulas, but not yet in the United States. (26)


Zinc

Zinc is a trace metal that is present in the brain and affects its structure and function. There is little evidence from animal and human studies that says zinc deficiency may lead to a slow down in cognitive development. However, it appears that zinc deficiency may lead to decreased neurologic functioning, activity, or motor development in children, therefore interfering with cognitive function. (27)


Iron

Iron deficiencies may cause problems with development and cognitive function in infants and preschoolers, lower work performance in adults, and increase the number of low birth weight babies, premature births, and death of the fetus during pregnancy. (28)


Iodine

Iodine deficiency in women during pregnancy may lead to poor cognitive function in children. More recently, it has been reported that iodine-deficient school-age children perform worse than children with normal iodine on reading and spelling and other general cognitive factors. (29)


Choline, Phosphatidyl Choline

Acetylcholine is the main brain chemical involved in memory and thought processes. Alzheimer’s disease is an illness where there is a decrease in the amount of acetylcholine that is made by the body. Both choline and phosphatidyl choline (PC) can be used to help make more acetylcholine. However, studies that used these supplements to improve cognitive function in patients with Alzheimer’s disease did not have much success. (30)

Improvements in cognitive function have been reported using a combination of choline and a drug named piracetam. Piracetam is a drug reported to increase cognitive function without side effects. It is available in over 85 countries throughout the world, but has not been approved by the FDA for use in the United States. A group of researchers decided to test a combination of choline and piracetam in patients suffering from Alzheimer’s disease. They reported that approximately 30% of the patients achieved improvements greater than what had been seen using either choline or piracetam alone. Based on these results, there may be a group of patients suffering from Alzheimer’s disease that can increase their cognitive function by taking a combination of choline and piracetam. (31)

Herbal Suplementation


Ginkgo

Ginkgo is among the oldest living species on earth and has been used as a medicine worldwide for centuries. It is the most frequently prescribed herb in Europe. It is reported to improve circulation in the elderly. (32) , (33) This can lead to improved memory, a delay in the start of Alzheimer's disease, (34) and a decrease in senile dementia, (35) tinnitus (ringing in the ears), (36) and vertigo (dizziness). (37) Memory improvement has also been reported in younger people as well.

The main active ingredients of ginkgo are the flavoglycosides. These compounds act as free radical scavengers or antioxidants. (38) Ginkgo is also reported to slow down platelet activating factor (PAF), which keeps platelets from sticking together, possibly improving circulation and decreasing the formation of blood clots. Ginkgo has also been reported to dilate blood vessels and have additional effects on the blood vessels to improve circulation. (39) , (40) Gingko reportedly acts as a tonic for the circulatory system. It may increase blood flow to the brain and bring more nutrition to the brain. (41) Ginkgo may also affect acetylcholine in the brain, improving cognitive function. (42)


Bacopa

Bacopa or water hyssop, is a plant that has been used since the sixth century A.D. in the traditional medical system of India for improving cognitive function and as a tonic for the nervous system. It has been traditionally used for epilepsy, mental illness, and to improve memory and mental function. (43) Bacopa has been reported to increase learning ability in laboratory animals. (44) Bacopa has been reported to be useful for improving intellectual behavior in children. In adults, bacopa has been reported to be effective in decreasing anxiety, improving brain function, enhancing memory, and improving mental performance. (45)

Bacopa is also reported to be helpful in children. Traditionally, it was used to anoint newborns with the hope of improving their intelligence, to "open the gate of Brahma" (Brahma being "creator" in the Hindu culture). Bacopa is still given in India to school age children for improving intellectual behavior.


Panax Ginseng (Asian)

Asian ginseng is one of the most frequently purchased herbal supplement in the United States. Historically, it has been used for people with fatigue or under stress. (46) Asian ginseng, or panax ginseng, is an adaptogen. This means that it helps the body to cope with various stresses in one’s life. These include physical, emotional, and external toxins that can increase a person’s risk for getting sick.

The main ingredients in panax ginseng are the ginsenosides. It is thought that ginsenosides work in the brain to increase the release of the hormone ACTH, leading to balance and a decrease in stress. (47) , (48) Panax ginseng has also been reported to improve stamina and learning ability, as well as having sedative and blood pressure-lowering properties. American ginseng (Panax quinquifolius) may be a better supplement for individuals who are coffee drinkers, are overweight, on prescription drugs, or troubled by insomnia. Asian ginseng (Panax ginseng) may be more suitable for individuals without high blood pressure, are athletes, have fatigue, or those people with high stress jobs.

Other ingredients of panax ginseng are reported to lower blood sugar in mice with diabetes and yet not affect normal lab animals. (49) Studies report that panax ginseng regulates insulin in the body.

Panax ginseng may offer some benefits as a general tonic for improved stamina and overall health, especially for stressful conditions, fatigue, concentration, and recovery from illness.


Vinpocetine

The lesser periwinkle plant (Vinca minor) is a native of many parts of Europe, growing in woods and thickets. Vinca has been used in cancer treatment as the drugs vincristine and vinblastine. Vinpocetine is a chemical found in the periwinkle plant. Vinpocetine has been used in Europe for more than twenty years for the treatment of brain circulation problems. (50) , (51) , (52) , (53)

Vinpocetine has been reported to have these actions: (54)

    Improve brain circulation and oxygen use in the brain Help the brain during times of hypoxia (lack of oxygen) and ischemia (decreased blood flow) Anticonvulsant (anti-seizure) action Improve properties of the blood Slow down clot formation


Huperzine A

Huperzine A comes from a club moss (Huperzia serrata) that has been used for centuries in Chinese folk medicine for conditions such as blood loss, fever, as a diuretic (water pill), and for irregular menstruation. (55) Modern science, especially in China, has looked at huperzine’s potential benefit in memory and learning, along with patients with Alzheimer's disease and dementia. (56) Huperzine A acts like pharmaceutical agents such as tacrine, currently prescribed for Alzheimer’s patients. (57) , (58) , (59) Laboratory animal studies have reported improvement in learning and memory. (60) , (61) Several human studies have been done over the past few years with huperzine A both in China and the United States. (62) , (63) , (64)

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