Magnetic Resonance Imaging of Human Olfactory Dysfunction

Han, Pengfei; Zang, Yunpeng; Joshi, Akshita; Hummel, Thomas

doi:10.1007/s10548-019-00729-5

Cited by 61 publications

(66 citation statements)

References 129 publications

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“…(1,30) . Although the exact mechanism behind olfactory recovery in health and disease is not entirely clear, previous electrophysiological imaging-based studies suggested that OT not only improves responsiveness of the olfactory epithelium (32) and the central processing of olfactory sensory information, but also increases olfactory related brain areas (such as the olfactory bulb or the grey matter volume) on a structural level (33) . Interestingly, longitudinal investigations on structural and functional changes in patients with posttraumatic OD receiving OT provided further evidence that recovery of olfactory function may be more pertained to top-down rather than bottom-up (peripheral-central) mechanisms (25) .…”

Section: O R R E C T E D P R O O Fmentioning

confidence: 99%

Factors associated with relevant olfactory recovery after olfactory training: a retrospective study including 601 participants

Liu¹,

Pellegrino²,

Sabha³

et al. 2020

Rhin

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Background: Olfactory training (OT) represents a therapeutic option for multiple etiologies of olfactory dysfunction (OD) that also benefits normosmic subjects. In this retrospective study, we report the effectiveness of OT and factors associated with relevant changes in olfactory function (OF) in large groups of normosmic participants and patients with OD, including a control group that performed no training. Methods: This was a retrospective pooled analysis including 2 treatment cohorts of 8 previously published studies. Adult participants that either presented with the major complaint of quantitative OD or normosmic volunteers were recruited at various ENT clinics and received OT or no training. The outcome was based on changes in objective olfactory test scores after OT. Results: A total of 601 patients with OD or normosmic subjects were included. OT was more effective compared to no training. No interaction was found between OT and OF. In multivariate analysis, higher baseline OF (adjusted odds ratio, aOR, 0.93) and posttraumatic (aOR, 0.29) or idiopathic OD (aOR, 0.18) compared to postinfectious causes were significantly associated with lower odds of relevant improvements in patients with OD receiving OT. Subgroup analysis of normosmic participants receiving OT further revealed a significant association of age and baseline olfactory function with improvements of overall OF. Conclusions: This study demonstrated that OT was more effective than no training in patients with various causes of OD. Additionally, baseline olfactory performance and etiology of OD were identified as important factors associated with relevant improvements after OT.

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Section: O R R E C T E D P R O O Fmentioning

confidence: 99%

Factors associated with relevant olfactory recovery after olfactory training: a retrospective study including 601 participants

Liu¹,

Pellegrino²,

Sabha³

et al. 2020

Rhin

View full text Add to dashboard Cite

show abstract

“…The architecture of the olfactory system and architecture of the gustatory system are well described [ 42 , 43 , 123 , 124 ]. The anatomy of both sensory systems is briefly reviewed.…”

Section: Involvement Of the Basal Ganglia Cerebellum And Sensorimentioning

confidence: 99%

“…There is no established drug treatment for subjects with impairment of the chemical senses due to a central nervous system disease [ 47 , 200 , 201 ]. Olfactory training improved olfaction in subjects with Parkinson’s disease [ 124 , 202 , 203 ]. For olfactory training, subjects sniff on cotton balls impregnated with different odors.…”

Section: Olfaction As a Potential Marker For Dystonia: Further Dirmentioning

confidence: 99%

Olfaction as a Marker for Dystonia: Background, Current State and Directions

et al. 2020

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Dystonia is a heterogeneous group of hyperkinetic movement disorders. The unifying descriptor of dystonia is the motor manifestation, characterized by continuous or intermittent contractions of muscles that cause abnormal movements and postures. Additionally, there are psychiatric, cognitive, and sensory alterations that are possible or putative non-motor manifestations of dystonia. The pathophysiology of dystonia is incompletely understood. A better understanding of dystonia pathophysiology is highly relevant in the amelioration of significant disability associated with motor and non-motor manifestations of dystonia. Recently, diminished olfaction was found to be a potential non-motor manifestation that may worsen the situation of subjects with dystonia. Yet, this finding may also shed light into dystonia pathophysiology and yield novel treatment options. This article aims to provide background information on dystonia and the current understanding of its pathophysiology, including the key structures involved, namely, the basal ganglia, cerebellum, and sensorimotor cortex. Additionally, involvement of these structures in the chemical senses are reviewed to provide an overview on how olfactory (and gustatory) deficits may occur in dystonia. Finally, we describe the present findings on altered chemical senses in dystonia and discuss directions of research on olfactory dysfunction as a marker in dystonia.

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“…Non-invasive neuroimaging modalities such as magnetic resonance imaging (MRI) have expanded the knowledge of olfactory dysfunction in humans ( Han et al, 2019 ). Anatomically, dysfunction in areas often implicated in ASD, such as the orbitofrontal and medial temporal areas including the amygdala, may be responsible for olfactory deficits ( Amaral et al, 2008 ; Stanfield et al, 2008 ; Tonacci et al, 2017 ).…”

Section: Introductionmentioning

confidence: 99%

Prefrontal Responses to Odors in Individuals With Autism Spectrum Disorders: Functional NIRS Measurement Combined With a Fragrance Pulse Ejection System

Minagawa

Kumazaki

et al. 2020

Front. Hum. Neurosci.

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Individuals with autism spectrum disorders (ASD) are impaired not only in social competencies but also in sensory perception, particularly olfaction. The olfactory ability of individuals with ASD has been examined in several psychophysical studies, but the results have been highly variable, which might be primarily due to methodological difficulties in the control of odor stimuli (e.g., the problem of lingering scents). In addition, the neural correlates of olfactory specificities in individuals with ASD remain largely unknown. To date, only one study has investigated this issue using functional magnetic resonance imaging (fMRI). The present study utilized a sophisticated method−a pulse ejection system−to present well-controlled odor stimuli to participants with ASD using an ASD-friendly application. With this advantageous system, we examined their odor detection, identification, and evaluation abilities and measured their brain activity evoked by odors using functional near-infrared spectroscopy (fNIRS). As the odor detection threshold (DT) of participants with ASD was highly variable, these participants were divided into two groups according to their DT: an ASD-Low DT group and an ASD-High DT group. Behavioral results showed that the ASD-High DT group had a significantly higher DT than the typically developing (control) group and the ASD-Low DT group, indicating their insensitivity to the tested odors. In addition, while there was no significant difference in the odor identification ability between groups, there was some discrepancy between the groups’ evaluations of odor pleasantness. The brain data identified, for the first time, that neural activity in the right dorsolateral prefrontal cortex (DLPFC) was significantly weaker in the ASD-High DT group than in the control group. Moreover, the strength of activity in the right DLPFC was negatively correlated with the DT. These findings suggest that participants with ASD have impairments in the higher-order function of olfactory processing, such as olfactory working memory and/or attention.

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Magnetic Resonance Imaging of Human Olfactory Dysfunction

Cited by 61 publications

References 129 publications

Factors associated with relevant olfactory recovery after olfactory training: a retrospective study including 601 participants

Factors associated with relevant olfactory recovery after olfactory training: a retrospective study including 601 participants

Olfaction as a Marker for Dystonia: Background, Current State and Directions

Prefrontal Responses to Odors in Individuals With Autism Spectrum Disorders: Functional NIRS Measurement Combined With a Fragrance Pulse Ejection System

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