Anosmia is a condition characterized by an inability to smell. While some may be
ID: 82275 • Letter: A
Question
Anosmia is a condition characterized by an inability to smell. While some may be unable to perceive a particular odorant, most suffering from this condition are unable to perceive multiple odorants. Based on your knowledge of the olfactory sense, propose several scenarios that would lead to a patient's diagnosis of anosmia. Patients suffering from hearing loss or impairment may be eligible for a cochlear implant, a device that mimics the action of the cochlea. Specifically, the cochlear implant contains external components that detect, process, and transmit sounds to an internal receiver. The internal components simulate the vestibulocochlear nerve directly. Based on your knowledge of hearing, describe how the cochlear implant allows for the perception of sound.Explanation / Answer
Answer 35:-
Anosmia is a condition in which sense of smell is completely lost. Person with anosmia may have perception of salty, sweet, sour, and bitter substances but lacks flavour discrimination, which largely depends on olfaction. With the loss of sense of smell there can also be a loss of taste. Distortion of function-foods or odours that normally are pleasant may taste or smell odd or distorted, perhaps with an unpleasant smell.
A simple test of olfaction can help in diagnosing anosmia (olfactory dysfunction). The test is performed to check olfaction by one nostril at a time. One nostril is pressed shut, and a pungent odour such as vial containing coffee, cinnamon, or tobacco is placed under the open nostril. The person, not able to recognise the substance, fails the test. Similarly other nostril is also checked for olfaction function. Though the test is crude, it gives idea about person’s ability to smell.
A more detailed test in which odor and taste identification and threshold detection is done can be performed by using commercially available testing kit. Some kits contain series of odours, whereas some kits involve sequential dilutions of an odorous chemical.
These tests are carried out for confirming diagnosis of anosmia. The underlying cause (tumor, polyp, infection, sinus etc) can be then detected by conducting appropriate medical/pathological tests (such as blood tests, CT scan etc).
Answer 36:-
Damage in the inner ear (cochlea) or auditory nerve is one of the causes of loss of hearing. Hearing aids amplify sounds so they may be detected by damaged ears. However, if ear damage is too severe, amplifying sound by hearing aids will have no effect.
A cochlear implant is an electronic medical device that replaces the function of the damaged inner ear. Cochlear implants bypass damaged portions of the ear and directly stimulate the auditory nerve. Signals generated by the implant are sent by way of the auditory nerve to the brain, which recognizes the signals as sound.
A cochlear implant consists of 2 main parts
The external part, that is, sound processor, which is mounted behind the ear sound processor is connected to battery via the lead. The antenna is magnetically attached to the skin directly over the internal part.
The internal part, that is, an implant, is surgically placed underneath the skin on the temporal bone. The receiver (implant) has an electrode array that is placed in the cochlea.
The sound processor captures and digitizes sound. The antenna transmits the digitized sound from the sound processor to the implant receiver. The magnetic implant receiver transforms the digital information into an electronic signal sent to the cochlea. The electrode array in the cochlea corresponds to a signal frequency. When the encoded signal is transmitted to the corresponding electrode, the auditory nerve is stimulated. The brain receives the sound transmitted via the auditory nerve.
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