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Investigation of cranial nerves. I pair: olfactory nerve (n. Olfactorius)
Last reviewed: 23.04.2024
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The function of the olfactory nerve: (perception of odors) provides several neurons from the nasal mucosa to the hippocampus.
The sense of smell is also checked in the presence of complaints of a violation of perception of odors, and without such, as often the patient himself does not realize that he has a sense of smell, but complains of a violation of taste (full taste sensations are possible only if the perception of food aromas is preserved) suspicion of a pathological process in the area of the anterior cranial fossa.
How is the olfactory examination performed?
To test the sense of smell, it is determined whether the patient distinguishes known smells - coffee, tobacco, soup, vanilla: ask him to close his eyes and determine the smell of the substance that is carried alternately to the right and left nostril (the second nostril should be clamped with the index finger of the hand). Do not use substances with a pungent odor (for example, ammonia), because they cause irritation of the receptors, not so much olfactory as the trigeminal nerve. The ability to distinguish odors in healthy individuals varies greatly, so when testing is more important, it is not whether the patient has been able to identify a particular substance by smell, or whether he noticed the presence of a smell in general.
Evaluation of results
Of particular clinical importance is the one-sided loss of smell, if it can not be explained by the pathology of the nasal cavity. Unilateral anosmia is more typical of neurological diseases than bilateral one. Unilateral or bilateral anosmia is a classic symptom of the olfactory fossa of the olfactory fossa. It is also characteristic for other tumors located in the list of cranial fossa. Anosmia may be a consequence of a traumatic brain injury. Bilateral anosmia often occurs in the cold, especially this is typical for the elderly.
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