13.10 CN I: Olfactory Nerves
The olfactory nerves (CN I) are tested in cases when the client has indicated a problem smelling things.
Steps for evaluating the functioning of the CN I include:
- Before assessing the nerve, test patency of the nasal passages. Have the client occlude one naris at a time while placing their index finger over the outside of the nose/nasal wing, then ask them to take a deep and quick inhalation in through the nose (like a sniff in which they draw air inwards as if trying to smell something). Note the client’s capacity to breathe inwards, demonstrating patent nasal passage. The client should be able to breathe inwards with no obstructions. Note: if the client is unable to occlude their own naris, you can press on the nasal wing to occlude the naris.
- Then, ask the client to occlude one naris at a time while placing their index finger over the outside of the nose/nasal wing.
- Ask the client to close their eyes.
- Place a familiar-smelling stimulant under the open naris and ask the client to identify the smell.
- Then, repeat steps 2 to 4 on the other nostril with a different stimulant.
- Normally, the client can identify the smell of the stimulant.
- Note unilateral (one side) or bilateral (both sides) loss of smell.
- Note the findings.
- Normal findings might be documented as: “CN I exam: smell intact bilaterally.”
- Abnormal findings might be documented as: “CN I exam: unilateral decrease of smell, left side.”
Contextualizing Inclusivity
It is important to use a familiar-smelling stimulant (e.g., toothpaste, mouthwash, coffee, vanilla extract). What is considered “familiar” is sometimes culturally dependent, so be aware of this when choosing stimulants and interpreting findings. Alongside of this, it is more important that the client perceives an odor than being able to identify the actual smell.
