Related Experiment Video

Updated: Sep 26, 2025

A Free-breathing fMRI Method to Study Human Olfactory Function
10:42

A Free-breathing fMRI Method to Study Human Olfactory Function

Published on: July 30, 2017

9.7K

Olfactory dysfunction in patients with multiple sclerosis; A systematic review and meta-analysis

Omid Mirmosayyeb1,2, Narges Ebrahimi2, Mahdi Barzegar1,2

  • 1Department of Neurology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.

Plos One
|April 19, 2022
PubMed
Abstract

Insights

Olfactory dysfunction, or impaired sense of smell, affects 27.2% of multiple sclerosis (MS) patients. This systematic review highlights the high prevalence of smell dysfunction in MS, urging greater clinical attention.

Area of Science:

  • Neurology
  • Ophthalmology
  • Otorhinolaryngology

Background:

  • Olfactory dysfunction is increasingly recognized in multiple sclerosis (MS) patients.
  • Prevalence rates vary, necessitating a comprehensive analysis.
  • This is the first systematic review and meta-analysis on this topic.

Purpose of the Study:

  • To estimate the pooled prevalence of olfactory dysfunction in MS patients.
  • To analyze smell function (TDI scores) in MS patients compared to controls.

Main Methods:

  • Systematic review and meta-analysis of studies up to January 2021.
  • Searched multiple databases (PubMed, Scopus, EMBASE, Web of Science, ProQuest) and gray literature.
  • Calculated pooled prevalence using a random-effects model; assessed publication bias.

Main Results:

  • Included 1099 MS cases from 897 articles and 2 conference abstracts.
  • Pooled prevalence of olfactory dysfunction in MS patients was 27.2%.
  • MS patients exhibited lower overall TDI scores, including Threshold, Discrimination, and Identification, compared to controls.

Conclusions:

  • Olfactory dysfunction is highly prevalent in multiple sclerosis patients.
  • This finding warrants increased clinical attention to olfactory issues in MS management.
  • Further research may elucidate the mechanisms and implications of smell loss in MS.

More Related Videos

Olfactory Assays for Mouse Models of Neurodegenerative Disease07:27

Olfactory Assays for Mouse Models of Neurodegenerative Disease

Published on: August 25, 2014

22.2K
Author Spotlight: Exploring Olfactory Influences on Corticospinal Excitability - Insights and Innovations in Neurological Research06:13

Author Spotlight: Exploring Olfactory Influences on Corticospinal Excitability - Insights and Innovations in Neurological Research

Published on: January 19, 2024

1.2K

Related Concept Videos

Olfactory Receptors: Location and Structure01:03

Olfactory Receptors: Location and Structure

The process of olfaction, also known as the sense of smell, is a sophisticated chemical response system. The specialized sensory neurons that facilitate this process, known as olfactory receptor neurons, are situated in an upper segment of the nasal cavity, known as the olfactory epithelium. Olfactory sensory neurons are bipolar, with their dendrites extending from the epithelium's apex into the mucus that lines the nasal cavity. Airborne molecules, when inhaled, traverse the olfactory...
9.7K
Olfaction01:25

Olfaction

The sense of smell is achieved through the activities of the olfactory system. It starts when an airborne odorant enters the nasal cavity and reaches olfactory epithelium (OE). The OE is protected by a thin layer of mucus, which also serves the purpose of dissolving more complex compounds into simpler chemical odorants. The size of the OE and the density of sensory neurons varies among species; in humans, the OE is only about 9-10 cm2.
The olfactory receptors are embedded in the cilia of the...
45.3K
Physiology of Smell and Olfactory Pathway01:20

Physiology of Smell and Olfactory Pathway

Humans detect odors with the help of specialized cells located in the upper part of the nasal cavity, called olfactory receptor neurons (ORNs). ORNs possess hair-like structures called cilia, which are receptive to sensations from the inhaled air. When an odorant molecule binds to a specific receptor on the cell of the cilia, it leads to a series of events that ultimately cause the ORN to send electrical signals to the olfactory bulb in the brain through the olfactory nerves.
The olfactory...
9.8K