Longitudinal Deep Phenotyping of Central Mechanisms in Dysosmia: A Pilot Study Using Electrobulbogram (EBG), Functional MRI (fMRI), and Diffusion-Weighted Imaging (DWI)

Conditions

• Anosmia
• COVID-19
• Depression
• Hyposomia
• Influenza
• Normosomia
• Parosmia
• Respiratory Tract Infection
• Rhinosinusitis
• Smell Disorder

Eligibility Criteria

Sex

ALL

Age

18 Years - 99 Years

Healthy Volunteers

Accepted

Study Details

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.

Key Dates

First listed

Sep 2, 2025

Start date

Jul 21, 2026

Status verified

Jun 2026

Primary completion

Sep 30, 2029

Completion

Oct 14, 2029

Study Design

Enrollment

80 participants (estimated)

Arms

• Arm: Anosmia
  participants with complete loss of smell
• Arm: Hyposmia
  participants with reduced smell sensitivity
• Arm: Normosmia (Healthy control cohort)
  participants with normal smell function
• Arm: Parosmia
  participants with a distorted smell perception

Primary Outcome Measure

Functional Connectivity Differences in Olfactory Dysfunction [ Time Frame: baseline, 3, 6, 9 and 12 months ]

Locations (1)

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