Olfactory and executive dysfunctions following orbito-basal lesions in traumatic brain injury

Guise, Élaine de; Alturki, Abdulrahman Y.; Laguë-Beauvais, Maude; LeBlanc, Joanne; Champoux, Marie-Claude; Couturier, Céline; Anderson, Kirsten; Lamoureux, Julie; Marcoux, Judith; Maleki, Mohammed; Feyz, Mitra; Frasnelli, Johannes

doi:10.3109/02699052.2015.1004748

Cited by 23 publications

(15 citation statements)

References 37 publications

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“…When we focused on the thalamus as a seed, we found that several frontal lobe regions (the OFL and SFG) appeared to have disrupted connectivity with the thalamus in SVCI. The relationship between the OFL and executive dysfunction has been well established and is supported by the fact that the patients with orbito-basal lesions in traumatic brain injury always exhibit executive dysfunction (de Guise et al, 2015 ). Additionally, the OFL is one of the origins of frontal-subcortical circuits and has reciprocal connections with the thalamus, which provides the direct structural basis for functional connectivity (Bonelli and Cummings, 2007 ).…”

Section: Discussionmentioning

confidence: 98%

Aberrant Functional Connectivity and Structural Atrophy in Subcortical Vascular Cognitive Impairment: Relationship with Cognitive Impairments

Zhou

Zhang

et al. 2016

Front. Aging Neurosci.

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Abnormal structures in the cortical and subcortical regions have been identified in subcortical vascular cognition impairment (SVCI). However, little is known about the functional alterations in SVCI, and no study refers to the functional connectivity in the prefrontal and subcortical regions in this context. The medial prefrontal cortex (MPFC) is an important region of the executive network and default mode network, and the subcortical thalamus plays vital roles in mediating or modulating these two networks. To investigate both thalamus- and MPFC-related functional connectivity as well as its relationship with cognition in SVCI, 32 SVCI patients and 23 control individuals were administered neuropsychological assessments. They also underwent structural and functional magnetic resonance imaging scans. Voxel-based morphometry and functional connectivity analysis were performed to detect gray matter (GM) atrophy and to characterize the functional alterations in the thalamus and the MPFC. For structural data, we observed that GM atrophy was distributed in both cortical regions and subcortical areas. For functional data, we observed that the thalamus functional connectivity in SVCI was significantly decreased in several cortical regions [i.e., the orbitofrontal lobe (OFL)], which are mainly involved in executive function and memory function. However, connectivity was increased in several frontal regions (i.e., the inferior frontal gyrus), which may be induced by the compensatory recruitment of the decreased functional connectivity. The MPFC functional connectivity was also decreased in executive- and memory-related regions (i.e., the anterior cingulate cortex) along with a motor region (i.e., the supplementary motor area). In addition, the cognitive performance was closely correlated with functional connectivity between the left thalamus and the left OFL in SVCI. The present study, thus, provides evidence for an association between structural and functional alterations, and sheds light on the underlying neural mechanisms of executive dysfunction in SVCI.

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Section: Discussionmentioning

confidence: 98%

Aberrant Functional Connectivity and Structural Atrophy in Subcortical Vascular Cognitive Impairment: Relationship with Cognitive Impairments

Zhou

Zhang

et al. 2016

Front. Aging Neurosci.

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“…Notably, patients with posttraumatic OD may also be unaware of their olfactory impairment, possibly due to cognitive dysfunction, hence generalizations for different etiologies based on the acuity of OD must be made very cautiously (43,44) . Our results are nevertheless necessary to serve as motivation for pursuing such longitudinal study in the future.…”

Section: Discussionmentioning

confidence: 99%

Individual importance of olfaction decreases with duration of smell loss

Liu¹,

Besser²,

Prem³

et al. 2020

Rhin

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Background: The personal importance of a lost neurologic-motor or sensory-function in several conditions has been shown to decrease as the afflicted patient becomes accustomed to not having that function. It is unknown how the importance of olfaction changes with duration of olfactory dysfunction (OD). The aim of this study was to evaluate the association between duration of smell loss and individual significance of olfaction, and whether this relationship would be modulated by other factors, such as etiology of smell loss. Methods: This is a retrospective study including a total 163 subjects with different degrees of olfactory function. Individual significance of olfaction was measured using the Importance of Olfaction Questionnaire (IOQ). Demographics, olfactory function, duration and etiology of OD were evaluated. Group comparisons, bivariate correlations, analyses of variance and multivariate linear regression were applied to detect differences and associations with the outcome measure of IOQ. Results: A significant negative correlation was found between duration of OD and the IOQ. Other important findings include a significantly higher IOQ in patients with posttraumatic-compared to idiopathic OD and in patients with higher aggravation scores compared to the lower aggravation group. Multivariate regression analysis further confirmed that duration of smell loss was independently associated with IOQ. Conclusions: The duration of smell loss is negatively correlated with the individual importance of olfaction, suggesting that patients develop coping mechanisms for adjusting to OD.

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“…[1][2][3][4] A single mTBI is associated with impaired olfaction that may involve contortion of the olfactory nerve and/or direct injury to the olfactory system (e.g., olfactory bulb in the ventral part of the frontal lobe or olfactory cortex structures, such as the frontal lobe base or MTL). 17,[19][20][21][22][23]26,27,29,79,80 In particular, in TBI (including mild), traumatic lesions in the frontal lobe in general, and the basal frontal lobe in particular, result in lower odor identification test scores relative to lesions anywhere else in the brain. 21,[79][80][81] The longitudinal effects of a single mTBI/concussion on olfaction are unclear because of the lack of prospective studies.…”

Section: Discussionmentioning

confidence: 99%

“…17,[19][20][21][22][23]26,27,29,79,80 In particular, in TBI (including mild), traumatic lesions in the frontal lobe in general, and the basal frontal lobe in particular, result in lower odor identification test scores relative to lesions anywhere else in the brain. 21,[79][80][81] The longitudinal effects of a single mTBI/concussion on olfaction are unclear because of the lack of prospective studies. However, it is noted that most head impacts in football occur at the front of the head 82 and RHI can lead to long-term structural and functional brain changes to olfactory structures, including the OFC, anterior corpus callosum, and MTL, and former NFL players have been shown to exhibit fMRI activation impairment of the frontal lobe, as well as hippocampal atrophy.…”

Section: Discussionmentioning

confidence: 99%

“…[14][15][16][17][18] Olfactory impairments in TBI are believed to involve tensile and shearing effects to the olfactory nerve at the cribriform plate, and/or direct injury to the olfactory system, including the olfactory bulb in the ventral aspect of the frontal lobe, and the olfactory cortex and processing regions (e.g., frontal lobe base, orbitofrontal cortex [OFC], and medial temporal lobes [MTLs]). [19][20][21][22][23][24][25][26][27] Like TBI, RHI has also been shown to impact olfactory function. One study found that active boxers (without nasal cavity pathology) exhibited worse olfactory function relative to controls, including decreased olfactory threshold and odor identification.…”

Section: Introductionmentioning

confidence: 99%

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Olfactory Function and Associated Clinical Correlates in Former National Football League Players

Alosco

Jarnagin

Tripodis

et al. 2017

Journal of Neurotrauma

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Professional American football players incur thousands of repetitive head impacts (RHIs) throughout their lifetime. The long-term consequences of RHI are not well characterized, but may include olfactory dysfunction. RHI has been associated with changes to brain regions involved in olfaction, and olfactory impairment is common after traumatic brain injury. Olfactory dysfunction is a frequent early sequelae of neurodegenerative diseases (e.g., Alzheimer's disease), and RHI is associated with the neurodegenerative disease, chronic traumatic encephalopathy (CTE). We examined olfaction, and its association with clinical measures, in former National Football League (NFL) players. Ninety-five former NFL players (ages 40-69) and 28 same-age controls completed a neuropsychological and neuropsychiatric evaluation as part of a National Institutes of Health-funded study. The Brief Smell Identification Test (B-SIT) assessed olfaction. Principal component analysis generated a four-factor structure of the clinical measures: behavioral/mood, psychomotor speed/executive function, and verbal and visual memory. Former NFL players had worse B-SIT scores relative to controls (p = 0.0096). A B-SIT cutoff of 11 had the greatest accuracy (c-statistic = 0.61) and specificity (79%) for discriminating former NFL players from controls. In the former NFL players, lower B-SIT scores correlated with greater behavioral/mood impairment (p = 0.0254) and worse psychomotor speed/executive functioning (p = 0.0464) after controlling for age and education. Former NFL players exhibited lower olfactory test scores relative to controls, and poorer olfactory test performance was associated with worse neuropsychological and neuropsychiatric functioning. Future work that uses more-comprehensive tests of olfaction and structural and functioning neuroimaging may improve understanding on the association between RHI and olfaction.

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Olfactory and executive dysfunctions following orbito-basal lesions in traumatic brain injury

Abstract: These findings add information regarding acute olfactory status following TBI and provide evidence on the importance of assessing olfaction very early post-TBI in order to plan intervention and determine what accident prevention advice will be required for home or work re-integration.

Cited by 23 publications

References 37 publications

Aberrant Functional Connectivity and Structural Atrophy in Subcortical Vascular Cognitive Impairment: Relationship with Cognitive Impairments

Aberrant Functional Connectivity and Structural Atrophy in Subcortical Vascular Cognitive Impairment: Relationship with Cognitive Impairments

Individual importance of olfaction decreases with duration of smell loss

Olfactory Function and Associated Clinical Correlates in Former National Football League Players

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