The Neurological Exam: Evaluating the Master Organ

Written by Gary Cordingley

How does a mind contemplate itself? That's a philosophical question I'll leave to minds smarter than mine, but what I can tell you is how to examinerepparttar brain and other parts ofrepparttar 148660 nervous system.

Most people are familiar with how doctors examine a heart or set of lungs. The physical exam of these organs consists mainly of using a stethoscope to listen to them in action. But when it comes to examining components ofrepparttar 148661 nervous system—consisting ofrepparttar 148662 brain, spinal cord, peripheral nerves and muscles—a stethoscope is pretty useless. The nervous system doesn't make sounds thatrepparttar 148663 doctor can listen to (thoughrepparttar 148664 arteries inrepparttar 148665 neck that deliver blood torepparttar 148666 brain can be usefully listened to). But because people can have medical disorders that damagerepparttar 148667 nervous system, it is every bit as important to have a method for evaluating this organ as for any other.

The method is calledrepparttar 148668 neurological exam. Because different parts ofrepparttar 148669 nervous system do different things,repparttar 148670 basic idea ofrepparttar 148671 neurological exam is to putrepparttar 148672 patient through a number of mini-exams, each evaluatingrepparttar 148673 function of a different component. And what a variety of functions there are! In fact, apart from exposure to an inspiring teacher, this is what drew me intorepparttar 148674 study of neurology inrepparttar 148675 first place—the sheer diversity ofrepparttar 148676 neurological exam.

This is an organ responsible for jobs as diverse as thinking, remembering, smelling, tasting, seeing, hearing, speaking, moving, walking, balancing, feeling and, yes, even contemplating itself—though I confess that my neurological exam doesn't include an assessment of self-contemplation. Moreover,repparttar 148677 nervous system handles many infrastructure tasks like controlling body-temperature, pulse, blood-pressure, breathing and enabling a person to urinate at a time and place of their choosing. What's not to admire about an organ system that can do so many things!

The many mini-tests ofrepparttar 148678 neurological exam are bundled together inrepparttar 148679 following sub-groupings: mental status exam, cranial nerve exam, motor exam, sensory exam and evaluation of stance and walking. I'll provide a brief overview of each.

The mental status exam focuses onrepparttar 148680 cerebrum which has a wrinkly, gray, outer surface usually shown in pictures ofrepparttar 148681 brain. The cerebrum is divided into eight lobes which includes pairs of frontal lobes, parietal lobes, temporal lobes and—bringing uprepparttar 148682 rear—the occipital lobes. Each handles different mental tasks. In fact, even within a lobe, many different jobs are handled. Sorepparttar 148683 usual mental status exam consists of observingrepparttar 148684 patient's behavior inrepparttar 148685 exam room and using a variety of standard tests to checkrepparttar 148686 patient's orientation to time and place, attention, memory, speech, comprehension of language, memory, calculation and ability to trackrepparttar 148687 relative positions of objects in space.

The next grouping of mini-tests,repparttar 148688 cranial nerve exam, also assessesrepparttar 148689 functioning of parts ofrepparttar 148690 cerebrum, but additionally focuses onrepparttar 148691 brainstem. The brainstem is located atrepparttar 148692 base ofrepparttar 148693 brain and connectsrepparttar 148694 cerebrum above torepparttar 148695 spinal cord below. The cranial nerve exam includes tests of smelling, vision, constriction ofrepparttar 148696 pupils, eye-movement, facial sensation, facial movement, hearing, and action of certain muscles inrepparttar 148697 throat, tongue, neck and shoulders.

Medical Tests: What Does a "Normal Range" Mean?

Written by Gary Cordingley

We have a marvelous array of medical tests available to us. Many of them—typically blood-tests—even come with results expressed in numbers signifyingrepparttar exact quantity of something that was measured. On laboratory reports these measured quantities are often accompanied by a "normal range" for whatrepparttar 148659 laboratory apparently thinksrepparttar 148660 value should have been, showing a lower number and a higher number. So if you had a laboratory test, what does it mean when your measurement falls inside or outside this range?

It all depends onrepparttar 148661 particulars. First of all, it matters what is being measured and why it was measured inrepparttar 148662 first place. In theory, a laboratory test is ordered whenrepparttar 148663 doctor poses a question for whichrepparttar 148664 laboratory test is supposed to provide an answer. (If there was no question, how couldrepparttar 148665 lab-test be an answer?) For example, suppose a doctor is wondering if your hand tremors are due to too much thyroid-hormone in your bloodstream. Sorepparttar 148666 doctor's question is: Does this person have too much thyroid-hormone inrepparttar 148667 bloodstream? A test measuringrepparttar 148668 thyroid-hormone would provide a clean answer if it was either too high (yes) or withinrepparttar 148669 normal range (no). Because thyroid-hormone levels that are too low do not produce tremors, a measurement that was too low would be irrelevant torepparttar 148670 question posed. It might still warrant consideration in its own right as an "incidental finding," but is no different than a within-range outcome in answeringrepparttar 148671 original question.

How aboutrepparttar 148672 same blood-test, but with a different question? Supposerepparttar 148673 doctor is trying to figure out why you gained weight. The doctor knows that some people gain weight when their thyroid glands produce too little thyroid-hormone. Sorepparttar 148674 doctor's question is: Does this person have too little thyroid-hormone inrepparttar 148675 bloodstream? This time, measuringrepparttar 148676 thyroid-hormone would provide a clean answer torepparttar 148677 question if it was lower thanrepparttar 148678 normal range (yes) or withinrepparttar 148679 normal range (no). Because elevated thyroid-hormone levels do not usually cause weight-gain, a number higher thanrepparttar 148680 normal range would produce an answer torepparttar 148681 original question no different than one that was within-range. (But even if this outcome was unexpected, it might still be followed up.)

For some blood-testsrepparttar 148682 only meaningful result is in one direction. For example, a blood urea nitrogen (BUN) measurement assesses kidney function. Ifrepparttar 148683 BUN measurement is too high, it could signify thatrepparttar 148684 kidney is impaired. But what does it mean if your BUN measurement is lower thanrepparttar 148685 normal range? It means absolutely nothing. It's a non-event. So then it's curious that a normal range for BUN even includes a lower number. How did it get there?

These examples lead up torepparttar 148686 question of howrepparttar 148687 normal ranges are created inrepparttar 148688 first place. They are produced by statistics generated by measurements obtained in healthy volunteers. Inrepparttar 148689 case ofrepparttar 148690 BUN measurement, for example, this substance might get measured inrepparttar 148691 blood of, say, 100 people without kidney disease. An average number would be calculated by addingrepparttar 148692 numbers produced by all 100 people, and then dividing by 100. This average would berepparttar 148693 center ofrepparttar 148694 normal range. Butrepparttar 148695 upper and lower numbers are produced by another method looking at how widely spread apartrepparttar 148696 BUN measurements are in these 100 people. After all, it would be highly unlikely that all 100 people would producerepparttar 148697 exact same number-value. So how far fromrepparttar 148698 average is still okay? The 100 measurements are plugged into a mathematical formula to compute a "standard deviation," a widely-used statistic related to how widelyrepparttar 148699 numbers are spread apart. Numbers that are farther apart produce a larger standard deviation, while numbers that are closer together produce a smaller standard deviation.

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