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Updated: Jun 26, 2026
10:42
A Free-breathing fMRI Method to Study Human Olfactory Function
Published on: July 30, 2017
Olfactory function in corticobasal syndrome and frontotemporal dementia
Matteo Pardini1, Edward D Huey, Alyson L Cavanagh
1Cognitive Neuroscience Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-1440, USA.
Archives of Neurology
|January 14, 2009
Summary
Olfactory recognition deficits are more severe in corticobasal syndrome (CBS) than previously thought. Formal olfactory testing, combined with cognitive assessments, can help differentiate CBS and frontal variant frontotemporal dementia (FTD-FV) from other neurodegenerative conditions.
Area of Science:
- Neuroscience
- Neurology
- Cognitive Science
Background:
- Formal olfactory testing can aid in differentiating neurological conditions like atypical parkinsonism, dementia, and psychiatric disorders at the bedside.
- The neural underpinnings of olfactory dysfunction, the impact of cognitive deficits on olfactory test outcomes, and the prevalence of olfactory deficits in corticobasal syndrome (CBS) and frontal variant frontotemporal dementia (FTD-FV) remain incompletely understood.
Purpose of the Study:
- To determine the prevalence of olfactory recognition deficits in patients clinically diagnosed with CBS or FTD-FV.
- To investigate the neural basis associated with olfactory recognition impairments in these patient groups.
Main Methods:
- A retrospective analysis was conducted using clinical, neuropsychological, and neuroimaging data.
- Participants included 25 patients with CBS, 22 with FTD-FV, and 12 age-matched healthy controls.
- Assessments comprised neuropsychological evaluations, formal olfactory recognition testing (University of Pennsylvania Smell Identification Test [UPSIT]), and voxel-based morphometry (VBM) of structural MRI scans.
Main Results:
- Mean UPSIT scores were significantly lower in the FTD-FV group (9.5%) compared to the CBS group (31.6%).
- VBM analysis revealed correlations between gray matter volume and UPSIT scores in specific brain regions, including the right insula and right/bilateral inferior frontal gyrus for CBS, and the right midfrontal gyrus for FTD-FV.
- Linear regression identified general memory scores (Wechsler Memory Scale) and naming test scores (Boston Naming Test) as significant predictors of UPSIT scores in FTD-FV patients, while the Mattis Dementia Rating Scale score was a predictor for CBS patients.
Conclusions:
- The study reveals a more pronounced olfactory impairment in CBS patients than previously documented.
- A significant association was found between olfactory recognition test performance and specific cognitive domains.
- These findings suggest that olfactory testing, when integrated with cognitive assessments, may offer a valuable tool for differentiating FTD-FV and CBS from other neurodegenerative and movement disorders.
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