Olfactory Disturbances (4 Types):
Quantitative Abnormalities
- Loss or reduction of sense of smell (anosmia or hyposmia)
- Can be from the nasal, neuroepithelial, or central level
- if bilateral, patient usually complains of ageusia (loss of taste)
- Increased olfactory acuity (hyperosmia)
- very rare, if exists
Qualitative Abnormalities
- distortions or illusions of smell (dysosmia or parosmia)
- May be associated with depressive illness
Olfactory Hallucinations/Delusions
- Always of central origin
- Most often due to temporal lobe seizures (uncinate fits)
Higher-order loss of discrimination (Olfactory Agnosia)
- Perceptual aspects intact, but deficits in recognition