Background:
Loss of the sense of smell can seriously affect a person's quality of life. The ability to smell can be damaged by many factors, including illnesses, injuries, and exposure to toxic chemicals. The effects can vary, including complete loss of smell, partial loss, and parosomia, which is when things smell differently than they should.
Objective:
To study how brain function changes in people with different types of smell disorders. Also, to look at how smell loss affects quality of life over time.
Eligibility:
People aged 18 years or older with a disorder that affects their sense of smell. Healthy volunteers are also needed.
Design:
Participants will have 5 study visits over 1 year. They will have various tests and procedures:
Smell tests. They will have several tests that involve smelling different items and answering questions.
Questionnaires. They will answer questions about their health, mood, sense of smell, and daily habits.
Magnetic resonance imaging (MRI) scans. They will lie on a bed that slides into a tube. Padding will hold their head still. They will smell different odors while in the scanner.
Electrobulbogram (EBG). They will wear a soft cap with sensors that measure brain activity. They will smell different odors while wearing the cap.
Nasal endoscopy. A flexible tube will be inserted into a nostril to view the inside of the nose.
Biopsy. A numbing substance will be sprayed into the nose. Then a scissor-like tool will be used to collect a sample of tissue from one or both nasal passages.
Samples of blood, urine, and nasal fluid will be taken.
Adult subjects, any sex, aged 18 or older.
Ability to understand and willingness to sign a written informed consent document.
Willingness and ability to comply with and participate in all study procedures and availability for the duration of the study.
Due to the extensive questionnaires (administered in English language only) that participants must complete independently, fluency in the English language is needed. Hence, participants must be able to read and understand English.
Compromised cognitive ability: Including dementia, intellectual disability, or severe learning disorders, traumatic brain injury,
Major psychotic and neurological condition: Examples include schizophrenia, bipolar disorder, Parkinson's disease, and multiple sclerosis, epilepsy.
Acute or chronic olfactory disorders.
Diagnosis of depression or anxiety.
The study will enroll adults aged 18 and older who are fluent in English and able to provide informed consent and comply with study procedures. Participants will include both healthy volunteers with normal smell and individuals with olfactory dysfunction of varying causes, such as post viral (including COVID-19), sinonasal disease, chemical exposure, or chemotherapy-related smell loss. To maintain consistency, preference will be given to participants who have experienced smell loss within the past year, through those with longer durations of dysfunction may be included.
Cohort
Prospective
Not listed
Functional Connectivity Differences in Olfactory Dysfunction
differences in functional brain connectivity between parosmia, anosmia and hyposmia groups, assessed longitudinally.
Structural Brain Changes in Olfactory Dysfunction
Structural brain architecture differences in olfactory-related regions, measured with neuroimaging.
Cognitive, Mood and Dietary Impact of Olfactory Dysfunction
Associations between olfactory function and changes in cognition, depressive symptoms and dietary habits, evaluated through surveys and behavioral measures.
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