Johannes Frasnelli

Johannes Frasnelli
Université du Québec à Trois-Rivières · Département d'Anatomie

MD, PD

About

161
Publications
38,912
Reads
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6,270
Citations
Additional affiliations
October 2013 - present
Hôpital du Sacré-Coeur de Montréal
Position
  • Researcher
January 2010 - April 2010
Monell Chemical Senses Center
January 2009 - present
Education
September 2009
Technische Universität Dresden
Field of study
  • medicine
February 2001
University of Vienna
Field of study
  • medicine

Publications

Publications (161)
Article
Full-text available
Objective: This longitudinal study aimed to evaluate olfactory perception in patients with first time mild traumatic brain injury (mTBI) 2-4 weeks (baseline) and 6 months (follow-up) following their trauma. Methods: At baseline, we enrolled 107 participants (54 healthy controls; 53 patients with mTBI). Thirty-nine healthy controls and 32 patient...
Article
It is well documented that early sensory loss typically alters brain morphology in the areas associated with the lost sense. However, much less is known about the impact of early sensory loss on the remainder of the sensory regions. Therefore, we investigated whether congenitally blind (CB) individuals show brain alterations in the olfactory system...
Article
Full-text available
Mice produce ultrasonic vocalizations (USVs) at different ages and social contexts, including maternal-pup separation, social play in juveniles, social interactions, and mating in adults. The USVs' recording can be used as an index of sensory detection, internal state, and social motivation. While sensory deprivation may alter USVs' emission and so...
Article
Full-text available
Brain plasticity is essential for experts to acquire the abilities they need. Sommeliers are olfaction experts who display differences in olfactory regions in the brain that correlate with greater olfactory abilities. While most studies on this topic are cross‐sectional, we used a longitudinal design and invited 17 sommelier students at the start a...
Article
Functional nasal surgery is frequently performed for sinonasal diseases not responding to medical treatment. Although surgery mostly turns out to be successful in such cases, a potential side effect of manipulating the nasal mucous membrane is impairment of intranasal trigeminal function. Not well known by specialists and clinically scarcely explor...
Article
Full-text available
Previous studies have reported that visual impairment can affect the quality of life leading to mental health disorders. This study aimed to investigate associations between vision impairment, depression and anxiety using a mouse model of congenital blindness. We phenotyped 15 anophthalmic and 17 sighted adult mice in a battery of tests for anxiety...
Article
Olfactory and gustatory dysfunctions (OD, GD) are prevalent symptoms following COVID-19 and persist in 6%–44% of individuals post-infection. As only few reports have described their prognosis after 6 months, our main objective was to assess the prevalence of OD and GD 11-month post-COVID-19. We also aimed to determine intraclass correlation coeffic...
Preprint
Full-text available
Background and Objectives: Olfactory and gustatory dysfunctions (OD, GD) are prevalent symptoms following COVID-19 and persist in 6%-44% of individuals in the first months after the infection. As only few reports have described their prognosis more than 6 months later, the main objective of this study was to assess the prevalence of OD and GD 11 mo...
Preprint
Full-text available
Background Idiopathic rapid eye movement sleep behavior disorder (iRBD) is a major risk factor for synucleinopathies, and patients often present with clinical signs and morphological brain changes. However, there is an important heterogeneity in the presentation and progression of these alterations, and the brain regions that are more vulnerable to...
Article
Objective: The emotional response to olfactory stimuli implies the activation of a complex cascade of events triggered by structures lying in the limbic system. However, little is known about how this activation is projected up to cerebral cortex and how different cortical areas dynamically interact each other. Approach: In this study, we acquir...
Article
Task‐based functional MRI neuroimaging for the study of cognitive neuroscience provides insight into how the brain responds to increasing cognitive demands. Theoretical models of neural‐cognitive relationships define neural efficiency and neural capacity as two parameters to describe the rate of gain of brain activity and the upper limits of the in...
Article
Full-text available
Several studies have revealed either self-reported chemosensory alterations in large groups or objective quantified chemosensory impairments in smaller populations of patients diagnosed with COVID-19. However, due to the great variability in published results regarding COVID-19-induced chemosensory impairments and their follow-up, prognosis for che...
Article
Full-text available
Olfactory decline is an early symptom of Alzheimer’s disease (AD) and is a predictor of conversion from mild cognitive impairment (MCI) to AD. Olfactory decline could reflect AD-related atrophy of structures related to the sense of smell. The aim of this study was to verify whether the presence of a clinical diagnosis of AD or MCI is associated wit...
Article
Full-text available
Background: The mechanisms by which any upper respiratory virus, including SARS-CoV-2, impairs chemosensory function are not known. COVID-19 is frequently associated with olfactory dysfunction after viral infection, which provides a research opportunity to evaluate the natural course of this neurological finding. Clinical trials and prospective an...
Preprint
Full-text available
Several studies have revealed either self-reported chemosensory alterations in large groups or objective quantified chemosensory impairments in smaller populations of patients diagnosed with COVID-19. However, due to the great variability in published results regarding COVID-19-induced chemosensory impairments and their follow-up, prognosis for che...
Article
Full-text available
Diagnosis of Parkinson's disease (PD) is commonly based on medical observations and assessment of clinical signs, including the characterization of a variety of motor symptoms. However, traditional diagnostic approaches may suffer from subjectivity as they rely on the evaluation of movements that are sometimes subtle to human eyes and therefore dif...
Article
Olfactory dysfunction (OD) is a highly frequent early non-motor symptom of Parkinson’s disease (PD). An important step to potentially use OD for the development of early diagnostic tools of PD is to differentiate PD-related OD from other forms of non-parkinsonian OD (NPOD: post-viral, sinunasal, post-traumatic and idiopathic OD). Measuring non-olfa...
Article
Full-text available
IntroductionThe trigeminal system is a chemosensory system, next to smell and taste, allowing intranasal sensations such as freshness, spiciness, etc. The lateralization task is used to measure trigeminal sensitivity and consists in identifying the nostril stimulated by an odorous substance in a two-alternative forced-choice procedure. However, whe...
Article
Background: Patients with anatomically unexplained, chronic nasal obstruction (CNO) that is refractory to medical treatment pose a challenge for clinicians. A surgical solution, addressing mechanical obstacles, is unsuited for these patients. CNO may result from disrupted airflow perception due to activation of the intranasal trigeminal system; th...
Conference Paper
Introduction: Olfactory dysfunction (OD) is a wellestablished consequence of traumatic brain injury (TBI). Most of the studies reported OD in patients with moderate and severe TBI in the acute phase. However, inconsistent results have been found on OD in patients with mild traumatic brain injury (mTBI). This study aims to investigate olfactory perc...
Conference Paper
Alzheimer’s disease (AD) is associated with olfactory deficits. The cerebral atrophy of structures related to olfaction has been found to lead to olfactory deficits in Alzheimer’s disease (AD). Interestingly, research has shown that conversion from mild cognitive impairment (MCI) to AD is better predicted with the addition of an olfactory identific...
Article
Episodic memory deficit is a symptom frequently observed after a mild traumatic brain injury (mTBI). However, few studies have investigated the impact of a single and acute mTBI on episodic memory and structural cerebral changes. To do so, we conducted two experiments. In the first, we evaluated verbal episodic memory by using a word recall test, i...
Article
The frequent association between coronavirus disease 2019 (COVID‐19) and olfactory dysfunction is creating an unprecedented demand for a treatment of the olfactory loss. Systemic corticosteroids have been considered as a therapeutic option. However, based on current literature, we call for caution using these treatments in early COVID‐19–related ol...
Article
Full-text available
(1) Background: It is well established that the insula is involved in olfaction, though its specific role in olfactory processing remains uncertain. In this paper, we first review the current literature on the insula and olfaction. Then, we describe the case of a 56-year-old man with a left insular cavernoma that caused olfactory disturbances. (2)...
Article
Background Respiratory tract viruses are the second most common cause for olfactory dysfunction. As we learn more about the effects of the severe acute respiratory syndrome coronavirus (SARS-CoV-2), with the recognition that olfactory dysfunction is a key symptom of this disease process, there is now a greater need for evidence-based management for...
Article
Background: Recently, subjective cognitive decline (SCD) has been considered to be one of the first signs of Alzheimer’s disease (AD). Since this potential early marker is sensitive but not specific to AD, combining it with other markers could ensure higher accuracy when predicting which persons with SCD will convert to AD. Since olfactory dysfunct...
Article
Full-text available
p>This is a correction notice for article bjaa041 (DOI: https:// doi.org/10.1093/chemse/bjaa041), published 20 June 2020. An incorrect version of the caption to Figure 5 was mistakenly included in the published paper. An updated version is given below. Neither the data nor the paper's conclusions were affected by this correction. The authors sincer...
Article
Full-text available
In a preregistered, cross-sectional study we investigated whether olfactory loss is a reliable predictor of COVID-19 using a crowdsourced questionnaire in 23 languages to assess symptoms in individuals self-reporting recent respiratory illness. We quantified changes in chemosensory abilities during the course of the respiratory illness using 0-100...
Conference Paper
A lesser known early symptom of Alzheimer’s disease is the olfactory decline. The ability to identify an odour may even be a predictor of conversion from mild cognitive impairment (MCI) to AD. This sensory decline could reflect AD‐related brain damage, including cerebral atrophy of structures related to the sense of smell. The aim of this systemati...
Article
Full-text available
Web search tools are widely used by the general public to obtain health-related information, and analysis of search data is often suggested for public health monitoring. We analyzed popularity of searches related to smell loss and taste loss, recently listed as symptoms of COVID-19. Searches on sight loss and hearing loss, which are not considered...
Article
Although often considered a non-dominant sense for spatial perception, chemosensory perception can be used to localize the source of an event and potentially help us navigate through our environment. Would blind people who lack the dominant spatial sense -vision- develop enhanced spatial chemosensation or, alternatively, suffer from the lack of vis...
Preprint
Full-text available
Diagnosis of Parkinson's disease (PD) is commonly based on medical observations and assessment of clinical signs, including the characterization of a variety of motor symptoms. However, traditional diagnostic approaches may suffer from subjectivity as they rely on the evaluation of movements that are sometimes subtle to human eyes and therefore dif...
Article
Full-text available
Background The olfactory bulb is one of the first regions of insult in Parkinson’s disease (PD), consistent with the early onset of olfactory dysfunction. Investigations of the olfactory bulb may, therefore, help early pre-motor diagnosis. We aimed to investigate olfactory bulb and its surrounding regions in PD-related olfactory dysfunction when sp...
Preprint
Full-text available
Now published in Chemical Senses doi: 10.1093/chemse/bjaa081. Background: COVID-19 has heterogeneous manifestations, though one of the most common symptoms is a sudden loss of smell (anosmia or hyposmia). We investigated whether olfactory loss is a reliable predictor of COVID-19. Methods: This preregistered, cross-sectional study used a crowdsou...
Article
Background: Olfactory dysfunction (OD) is a frequent symptom of Parkinson's disease (PD) that appears years prior to diagnosis. Previous studies suggest that PD-related OD is different from non-parkinsonian forms of olfactory dysfunction (NPOD) as PD patients maintain trigeminal sensitivity as opposed to patients with NPOD who typically exhibit re...
Article
Full-text available
Recent anecdotal and scientific reports have provided evidence of a link between COVID-19 and chemosensory impairments such as anosmia. However, these reports have downplayed or failed to distinguish potential effects on taste, ignored chemesthesis, and generally lacked quantitative measurements. Here, we report the development, implementation and...
Article
This longitudinal study aimed to evaluate qualitative (parosmia) and quantitative (hyposmia/anosmia) olfaction 2-4 weeks (baseline) and six months (follow-up) after a mild traumatic brain injury (mTBI). We further evaluated the predictive value of baseline depression, anxiety and olfaction scores on depression and anxiety at follow-up. At baseline,...
Preprint
Full-text available
Now published in Chemical Senses doi: 10.1093/chemse/bjaa041. Recent anecdotal and scientific reports have provided evidence of a link between COVID-19 and chemosensory impairments such as anosmia. However, these reports have downplayed or failed to distinguish potential effects on taste, ignored chemesthesis, generally lacked quantitative measure...
Article
Objective : The role of the clinical neuropsychologist in tertiary trauma center hospitals is to quickly assess the global cognitive functioning of patients who have sustained a traumatic brain injury (TBI) in order to determine their orientation at the time of discharge. However, the few global cognitive instruments available for this clinical pur...
Preprint
Full-text available
Evidence of smell loss in COVID-19 is growing. Researchers and analysts have suggested to use Google searches on smell loss as indicators of COVID-19 cases. However, such searches may be due to interest elicited by media coverage of the COVID-19-related smell loss, rather than attempts to understand self-symptoms. We analyzed searches related to 4...
Article
Olfactory dysfunction (OD) in Parkinson's disease (PD) appears several years before the presence of motor disturbance. Olfactory testing has the potential to serve as a tool for early detection of PD, but OD is not specific to PD as it affects up to 20% of the general population. Olfaction includes an orthonasal and a retronasal components; in some...
Article
Full-text available
The aim of this study is to investigate the effect of olfactory dysfunction (OD) on the two other chemical senses, namely gustation and the intranasal trigeminal system. Taste and trigeminal function were analyzed in a retrospective cross-sectional study of 178 participants with OD (n = 78 posttraumatic, n = 42 idiopathic, n = 27 post-infectious an...
Article
Full-text available
Recent anecdotal and scientific reports have provided evidence of a link between COVID-19 and chemosensory impairments such as anosmia. However, these reports have downplayed or failed to distinguish potential effects on taste, ignored chemesthesis, and generally lacked quantitative measurements. Here, we report the development, implementation and...
Article
Full-text available
Olfactory dysfunction is a frequent early non-motor symptom of Parkinson’s disease (PD). There is evidence that with regard to trigeminal perception, PD-related olfactory dysfunction is different from other olfactory disorders. More specifically, trigeminal sensitivity, when measured behaviorally, was unimpaired in PD patients as opposed to patient...
Article
Full-text available
Introduction Experts acquire superior abilities in their specific domains by training. Sommelier students, who are future olfaction experts, could be an excellent model to study the effects of olfactory training. Methods We tested whether sommelier students display superior olfactory abilities early in their education: within the first 2 months of...
Article
Vulnerability to obesity includes eating in response to food cues, which acquire incentive value through conditioning. The conditioning process is largely subserved by dopamine, theorized to encode the discrepancy between expected and actual rewards known as the reward prediction error (RPE). Ghrelin is a gut-derived homeostatic hormone that trigge...
Article
Full-text available
Objective: This cross-sectional study aimed to evaluate olfaction 24 h (baseline) and 1 year (follow-up) after a mild traumatic brain injury (TBI). We further evaluated the influence of the cognition and affective state on olfactory function. Method: At baseline, olfactory function, neuropsychological, and affective states were assessed in 42 patie...
Chapter
With every breath we take, we sample the chemical composition of our environment. Minute amounts of odor sources reach the olfactory epithelium and trigger a cascade of events in the brain. This leads to the perception of odors, although in many circumstances we are not aware of our odorous environment. Next to detection and identification of smell...
Article
Training and repeated exposure to odorants leads to enhanced olfactory sensitivity. So far, the efficacy of intensive olfactory training on olfactory function in a healthy population and its underlying neurobiological basis remain poorly known. This study investigated the effects of a 6-week intensive and well-controlled olfactory training on olfac...
Chapter
Many odors activate the intranasal chemosensory trigeminal system where they produce cooling and other somatic sensations such as tingling, burning, or stinging. Specific trigeminal receptors are involved in the mediation of these sensations. Importantly, the trigeminal system also mediates sensitivity to airflow. The intranasal trigeminal and the...
Article
Full-text available
Vulnerability to obesity includes eating in response to food cues, which acquire incentive value through conditioning. The conditioning process is largely subserved by dopamine, theorized to encode the discrepancy between expected and actual rewards known as the reward prediction error (RPE). Ghrelin is a gut-derived homeostatic hormone that trigge...
Article
Full-text available
Identifying odors within mixtures is a difficult task: humans are able to recognize only up to 4 odors within a mixture. We wanted to test the effects of olfactory training on this ability. We used 7 odorants to create 35 olfactory stimuli of 1, 2, 3, 4, or 5 odorants. The task consisted of identifying the odorants present within the mixture. We tr...
Article
Blind individuals display superior sensory abilities in other modalities, yet results remain contradictory regarding their performance on olfactory tasks. Using complex ecological olfactory tasks, we evaluated the impact of blindness on olfactory performance. We tested 12 early-blind individuals (M = 49,SD = 13.09) and 12 sighted controls (M = 49,S...
Article
The olfactory and trigeminal systems are intimately connected as most odorants stimulate both sensory systems. They interact by mutually suppressing and enhancing each other. However, the location and the degree of their interaction remain unclear. One method to test sensitivity in the trigeminal system is the odor localization task: when an odoran...
Preprint
Full-text available
Vulnerability to obesity includes eating in response to food cues, which acquire incentive value through conditioning. The conditioning process is largely subserved by dopamine, theorized to encode the discrepancy between expected and actual rewards, known as the reward prediction error (RPE). Ghrelin is a gut-derived homeostatic hormone that trigg...
Article
In the past few decades, several olfactory tests have been developed to assess olfactory performance and detect disorders. Contrary to other sensory systems, both nostrils are usually tested together; we hypothesized that monorhinal testing may reveal side differences in sensitivity which may be useful for the diagnosis of olfactory dysfunction. Us...
Article
Full-text available
Background: Olfactory dysfunction is an increasingly recognised condition, associated with reduced quality of life and major health outcomes such as neurodegeneration and death. However, translational research in this field is limited by heterogeneity in methodological approach, including definitions of impairment, improvement and appropriate asse...
Conference Paper
Sommeliers, who are experts in wine, have superior olfactory abilities compared to the average wine drinker. However, it is unclear whether this difference is the result of extensive training, or whether sommeliers exhibit superior abilities before the training (implying that individuals with superior olfactory abilities are more likely to become s...
Article
Full-text available
Background: Olfactory dysfunction is an increasingly recognised condition, associated with reduced quality of life and major health outcomes such as neurodegeneration and death. However, translational research in this field is limited by heterogeneity in methodological approach, including definitions of impairment, improvement and appropriate asse...
Article
The trigeminal system is a chemosensory system participating in the perception of most odorants, which allows for the perception of diverse sensations including the freshness of eucalyptus or the spiciness of pepper. The lateralization task, that is, the identification of the stimulated nostril in a monorhinal stimulation paradigm is only possible...
Chapter
The intranasal trigeminal system is a third chemical sense next to smell and taste. The trigeminal nerve's free endings innervate the facial mucosa and the skin and convey sensory information arising from contact of a stimulus with the facial skin or the face's mucosa. The activation of polymodal nociceptors via a ligand-receptor interaction induce...
Chapter
The trigeminal nerve is the fifth and thickest cranial nerve and not only it is responsible for facial sensation and motor functioning, but it is also responsible for chemosensory perception. On top of innervating the skin of the face, the trigeminal nerve also innervates the mucosa of the nose and mouth. Here, chemosensory perception starts with t...