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From Wikipedia

Hearing test

A hearing test provides an evaluation of the sensitivity of a person's sense of hearing and is most often performed by an audiologist using an audiometer. An audiometer is used to determine a person's hearing sensitivity at different frequencies. There are other hearing tests as well, e.g. Weber test and Rinne test.

Audiometer

An audiometer hearing test is usually administered to a person sitting in a soundproof booth wearing a set of headphones which is connected to an audiometer. Small foam insert earphones placed in the ears may also be used. The audiometer produces tones at specific frequencies and set volume levels to each ear independently. The audiologist or licensed hearing aid specialist plots the loudness, in decibels, on an audiogram. People having their hearing tested will convey that they have heard the tone by either raising a hand or pressing a button. As the test progresses, the audiologist or hearing aid specialist, plots points on a graph where the frequency is on the x-axis and the loudness on the y-axis. Once each frequency of hearing ability is tested and plotted, the points are joined by a line so that one can see at a glance which frequencies are not being heard normally and what degree of hearing loss may be present. Normal hearing at any frequency is a sound pressure of 20dBSPL or quieter; with worsening hearing as the number increases.

Weber and Rinne

A complete hearing evaluation involves several other tests as well. In order to determine what kind of hearing loss is present, a bone conduction hearing test is administered. In this test, a vibrating tuning fork is placed behind the ear, on the mastoid process. When the patient can no longer feel/hear the vibration, the tuning fork is held in front of the ear; the patient should once more be able to hear a ringing sound. If they cannot, there is conductive hearing loss in that ear. Additionally, the tuning fork is placed on the forehead. The patient is then asked if the sound is localised in the centre of the head or whether it is louder in either ear. If there is conductive hearing loss, it is likely to be louder in the affected ear; if there is sensorineural hearing loss, it will be quieter in the affected ear. This test helps the audiologist determine whether the hearing loss is conductive (caused by problems in the outer or middle ear) or sensorineural (caused by problems in the cochlea, the sensory organ of hearing) or neural - caused by a problem in the auditory nerve or auditory pathways/cortex of the brain.

Other

  • The audiologist or hearing aid specialist may also conduct speech tests, wherein the patient repeats the words he or she hears.
  • In addition, a test called a tympanogram is generally done. In this test, a small probe is placed in the ear and the air pressure in the ear canal is varied. This test tells the audiologist how well the eardrum and other structures in the middle ear are working. The ear canal volume indicates whether a perforation in the eardrum (tympanic membrane) may be present. The middle ear pressure indicates whether any fluid is present in the middle ear space (also called "glue ear" or "otitis media with effusion"). Compliance measurement indicates how well the eardrum and ossicles (the three ear bones) are moving.
  • The last test the audiologist may perform is an acoustic reflex test. In this test a probe is placed in the ear and a loud tone, greater than 70 dBSPL, is produced. The test measures the reflexive contraction of the stapedius muscle, which is important in protecting the ear from loud noises, such as a person's own speech which may be 90dBSPL at the eardrum. This test can be used to estimate the hearing thresholds in patients who are unable to perform normal pure tone audiometry and can also give information about the vestibular and facial nerves and indicate if a lesion may be present.


From Yahoo Answers

Question:If a person swallowed a poison like aromatheropy oils, is it possible that if that pioson stimulated the heart for too long, too hard, that it could damage the vagus nerve suppling electrical currents to the heart in such a way that ECGs would never pick up an arrythmias dispite the heart beating fast, irregulary, and hard there-after due to perminant damage? It would appear normal on the ECG because the SA node, AV node and all other nervous tissue in the heart was working fine and producing no short-curciuts in the heart it's self. It would mean that the stomach digesting food and girgling would make the heart rhythm go wrong due to the vagus involvement. What would the treatment be? How do you get a cardiologist to look at this problem? How do you go about sorting that problem out if you have this syndrome? WARNING - Bare in mind that the ECG can occasionally fail to pick up arrythmias for a number of reasons. 1) Because there are no symptoms or triggers of the problem at the time of the tracing. 2) Because it is one of those rare cases that can fail to be detected by ECG. It does happen. NOTE - The stomach does not normally lead to arrythmias, but in this case it is involving the vagus nerve, and may also be because the stomach is causing the heart to move such that faulty connections in the nerves are jossled, leading to even worse miss-firing problems. CREED

Answers:This question has a lot of confusion in it, and it sounds like maybe you're worried about your heart because of something you may have accidently taken internally that you think you shouldn't have. If you have worries about your physical condition, you should bring them to the attention of a doctor and be completely honest with them about what your worry is and why you're worried about it. They will be able to give you much better advice than anyone over the intenet can! That being said, I can help you understand a few things about the topics you brought up in your question, and it may make you feel a little bit better. Let's start with ECG. ECG is a measurement of electrical activity in the region of the heart. It's sensitive enough to pick up the "firing" of electrical impulses that cause heart muscle contraction. Although it is possible to have muscular movement changes that aren't well detected by ECG, it's not going to miss a RHYTHM disturbance unless the arrhythmia is transient and fails to occur during the study. For this type of subtle problem, a 24 hour monitor is used called a "Holter monitor". The ECG is actually quite a sensitive and informative study. A completely normal ECG is extremely reassuring as there are specific ECG findings that occur if any of the heart muscle or its conduction system is "permanently damaged". Permanent damage in this sense would mean that some tissue in the heart organ has died and has been replaced by scar. The absence of those findings RULES OUT the presence of this type of damage. Any rhythm disturbances that come and go are related to problems of heart tissue that is still alive. The vagus nerve is a system of fibers that control automatic functions in the organs of the chest and abdomen. In the heart muscle, vagus nerve stimulation causes slowing. This is not a major part of the mechanism by which rhythm is determined within the heart. It functions more to globally affect the behavior of the heart with respect to how much work output the body needs the heart to perform. The mechanism with which the vagus nerve interacts with the heart involves a chemical release. This chemical is called acetylcholine, and is an extremely common chemical throughout the body, used as a neurotransmitter. There are a number of ways that it functions in different parts of the body and there are two basic classes of cell surface receptor for it (muscarinic and nicotinic). Medical problems related to acetylcholine derrangements are well understood. There are a number of ways that this can happen and they classically relate to toxic substances. However, one thing about toxic exposures is that they affect the WHOLE BODY. Chemicals don't go to just one place in the body unless they are delivered in very precise ways. Taking something by mouth is extremely imprecise!! I know nothing about the toxicology of aromatherapy agents. However, I can say that it would be essentially impossible for a toxic agent which has action against acetylcholine-related physiology, taken orally, to affect just one organ. It would affect LOTS OF THINGS and the problems it would create would be GLARING and OBVIOUS, not subtle at all!!!! Acetylcholine DOES interact with the gut. Vagal stimulation of the gut increases activity. So do quite a lot of other things. Gut motility is a COMPLICATED phenomenon. Interestingly, the vagus nerves to the gut can affect the heart. Typically, with enough stimulation to those gut-related vagus nerve branches, there will be some reflexive slowing of the heart rate. However, there will not be frank rhythm disturbance. My biggest concern is this: There is a tendency for people to not want to talk to doctors, and this can be for any number of reasons from mistrust and embarassment, to fear of what they might actually find out. This tendency is completely antithetical to the treatment process and it only hurts the patient. One thing I've seen many times is that people will ask better questions to a doctor that isn't "their doctor", and I see that all the time, here on Yahoo Questions. If people asked questions to their own doctors as clearly as they do here, they'd get great answers... but instead, when they get to the doctor's office, they freeze up. The key is to be honest... brutally and disarmingly honest. If your concern is that you may have taken something by mouth and you're concerned about it's possible toxic effects, then see a doctor of internal medicine and tell them, "I took something by mouth (by accident or whatever) and I'm concerned that it may have toxic effects." Then specify what you ingested, how much, and when. Having a sample or the empty bottle would be very helpful. If the doctor is not aware of this particular chemical, there are registered lists of ingredients and their toxic effects that are instantly available by phone or by fax, 24 hours a day. If your concern is about your heart, tell the doctor, "I'm concerned about my heart." The doctor will then ask you why. Answer this question with a description of what you actually experience, for example, "sometimes I feel like my heart is racing for no reason and I feel thumping palpitating feelings in my chest... and then it goes away..." or, "I get chest pains when I exert myself and feel short of breath." If a routine ECG is normal, then there is no evidence of "permanent damage". If there are transient episodes of concern, then the doctor will probably want to get the result of a 24 hour monitor that you wear home and go about your daily business with. My strong recommendation is that if you have concerns about a possible medical condition, you seek the input of a doctor who is right there with you, face to face. This doctor can examine you and work with your concerns in a way that I cannot here over the internet. I can only read what you write and attempt to read between the lines a little bit. A doctor that you are physically examined by can do much much better. I hope that helps. I hope that you are not too distressed.

Question:

Answers:On old olympus towering tops, a finn and german viewed some hops. Each letter of the first word of above sentence represents one of the nerves... I remember this from college, but don't ask me to name all of them ! Had to google them: Olfactory I ON Optic II OLD Oculomotor III OLYMPUS Trochlear IV TOWERING Trigeminal V TOPS Abducens VI A Facial VII FIN Auditory (vestibulocochlear) VIII AND Glossopharyngeal IX GERMAN Vagus x VIEWED Spinal Accessory XI SOME Hypoglossal XII HOPS

Question:Also, what is the zapping part?

Answers:Although the test is sometimes described as an "EMG" for short, typical electrodiagnostic studies involve two parts: nerve conduction studies (NCS) and electromyography (EMG). In nerve conduction studies, the doctor stimulates the nerve with an electrical impulse (which feels like a mildly unpleasant static shock) and records the conduction of the electrical impulse at another location. This allows the doctor to figure out how well the nerve is transmitting information and whether there is something wrong with the nerve's conduction of impulses. In the needle EMG portion of the test, the doctor places small needles into the muscles to measure the electrical activity of the muscles, which helps to tell if the muscle has lost its nerve supply or if the muscle is damaged by some other problem.

Question:hello, could someone tell me what cranial nerves we are testing in the gag reflex (neurological examination), i guess its 9 and 10 right? and can you tell me whether we are testing motor or sensory fibres

Answers:It's the vagus nerve (CNX). Testing the gag reflex gives you information on both sensory and motor fibers - - sensation of the stimulus that triggers the reflex and then the movement of the soft palate in response.

From Youtube

Air Testing for Nerve Agents 1963 :In the 1950s, the US began developing detection and warning systems for chemical warfare agents (CWAs). The early detection kits significantly improved a soldiers ability to detect the presence of CWAs. However, it soon became apparent that they were difficult to use under battlefield conditions. Each kit contained breakable components and the procedures required to conduct the various tests were difficult to accomplish while wearing protective gear. In 1968, the US military developed the M8 Portable Automatic Chemical Agent Alarm, the first mass-produced field detector for nerve agents. This was a significant accomplishment in chemical defense and this new fielded technology corrected a major deficiency that had made US soldiers vulnerable to a surprise nerve agent attack. This is clipped from the 1963 film, Nerve Agents, available at the US National Archives. The film is from the US Army Training Film series on the features and tactical use of GA (tabun), GB (sarin), and V-class nerve agents as munitions for chemical warfare. Explains how the nerve gas agents enter the human body and the symptoms of poisoning, and shows the protective and first-aid measures that may be taken against them.