There are numerous studies indicating thatanosmia, or the loss of the sense of smell, is associated with dementia andneurodegenerative diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), and Lewy body disease (LBD). Even though the scientific community seems to be in agreement that there is a relationship between olfactory impairments and neurodegenerative diseases, the nature of this relationship has not been fully established. For example, some research indicates that the loss of smell can be a predictive factor for developing AD, PD, or LBD, but other studies report that this symptom is not pronounced enough to be of diagnostic value. Additionally, it does not appear that an impaired sense of smell can be used in the absence of other symptoms or diagnostic tests to differentiate between the different neurodegenerative conditions.