Olfactory function and dysfunction in humans
Compared to other sensory modalities, the physiology and pathophysiology of olfaction remains poorly explored in humans. Yet, olfactory disorders are common in the general population, affecting up to 20% of the population. Over the recent years, the recording of ERPs triggered by the transient presentation of odorants has been receiving strong and increasing interest. The approach is not only of interest for basic researchers aiming to characterize the cortical representation of odors in humans. Indeed, it is also of great interest for clinicians currently needing objective and robust tools to diagnose disorders of olfaction. In addition, the recording of chemosensory ERPs could contribute to the early diagnosis of neurodegenerative disorders in which olfactory dysfunction is thought to constitute an early and specific sign, in particular, Alzheimer’s disease. Unfortunately, olfactory chemosensory ERPs exhibit a very low signal-to-noise ratio. Hence, although the technique is recognized as having great potential, its current usefulness remains very limited, particularly in the context of clinical diagnosis.
In a first project, we hypothesize that the low signal-to-noise ratio of chemosensory ERPs could at least in part be due to an important amount of temporal jitter affecting the brain responses to chemosensory stimulation, itself due to the number of steps required for transduction of the chemosensory stimulus into a neural impulse. For this reason, we develop an approach to reveal olfactory EEG responses that are not strictly phase-locked to the onset of the stimulus, using a method based on the continuous wavelet transform. We found that this approach significantly enhances the signal-to-noise ratio of the elicited responses, and discloses an important fraction of the cortical activity to chemosensory stimulation that is lost by conventional time-domain averaging. By providing a more complete view of how odors are represented in the human brain, we believe that our approach could constitute the basis for a robust clinical tool to assess olfaction in humans.

Researchers involved
Publications
2020
Adaptation of the Sniffin Sticks Test in South-Kivu
European Annals of Oto-rhino-laryngology, Head and Neck diseases
Balungwe P, Huart C, Matanda R, Bisimwa G, Mouraux A, Rombaux P.
S1879-7296(20)30032-6
2020
Mechanisms linking olfactory impairment and risk of mortality
Frontiers in Neuroscience
Van Regemorter V , Hummel T, Rosenzweig F, Mouraux A, Rombaux P, Huart C.
0.680555556
2019
Development of a new psychophysical method to assess intranasal trigeminal chemosensory function
Rhinology
Huart C, Hummel T, Kaehling C, Konstantinidis I, Hox V, Mouraux A, Rombaux P.
57(5): 375-384
2019
Neural plasticity in developing and adult olfactory pathways - focus on the human olfactory bulb
Journal of Bioenergetics and Biomembranes
Huart C, Rombaux P, Hummel T.
51(1):77-87
2018
Parkinson disease in eldery patients: lessons from odour detection thresholds on olfacto-trigeminal interaction
Rhinology
Foguem C, Lemdani M, Huart C.
56(2):127-132
2016
Brain lesion-pattern analysis in patients with olfactory dysfunctions following head trauma
Neuroimage Clinical
Lötsch J, Ultsch A, Eckhardt M, Huart C, Rombaux P, Hummel T.
11:99-105
2016
Post-injury smell disorders
B-ENT
Rombaux P, Huart C, Balungwe P, de Toeuf C, Collet S, Duprez T.
Suppl 26(2):39-46
2016
Olfaction in Chronic Rhinosinusitis
Current Allergy and Asthma Reports
Rombaux P, Huart C, Levie P, Cingi C, Hummel T.
16(5):41
2015
Unirhinal olfactory testing for the diagnostic workup of mild cognitive impairment
Journal of Alzheimer's Disease
Huart C, Rombaux P, Gérard T, Hanseeuw B, Lhommel R, Quenon L, Ivanoiu A, Mouraux A.
47(1): 253-270
2015
Volume of olfactory bulb and depth of olfactory sulcus in 378 consecutive patients with olfactory loss
Journal of Neurology
Hummel T, Urbig A, Huart C, Duprez T, Rombaux P.
262(4):1046-51
2014
Olfactory event-related potentials in infants
The Journal of Pediatrics
Schriever VA, Gois-Eanes M, Schuster B, Huart C, Hummel T.
165(2): 372-375
2013
Plasticity of the human olfactory system : the olfactory bulb
Molecules
Huart C, Rombaux P, Hummel T.
18(9): 11586-600