CHICAGO -- June 16, 2008 -- The olfactory bulb in the brain appears to change in size in a way that corresponds to individual alterations in sense of smell, according to a report in the June issue of Archives of Otolaryngology-Head & Neck Surgery.
Antje Haehner, MD, University of Dresden Medical School, Dresden, Germany, and colleagues, studied 20 patients with olfactory loss. Once between 2003 and 2004 and again 13 to 19 months later, patients underwent an assessment that included magnetic resonance imaging (MRI) of the brain and nasal endoscopy. Their olfactory function was tested using a kit that measures individuals' threshold of detecting odours, ability to discriminate between odours, and identification of particular odours.
At the first assessment, 7 of the 20 patients had anosmia and 13 had a reduced hyposmia, while at the second assessment 6 had anosmia and 14 had hyposmia. In patients who initially had hyposmia, the volume of the olfactory bulb increased as olfactory function increased. However, no correlation was found between the volume of the olfactory bulb and the ability to distinguish between or identify specific odours.
"The correlation between olfactory bulb volume and olfactory function may potentially be used in combination with other factors influencing olfaction such as remaining olfactory function, age, and duration of olfactory loss as a means to provide patients with individual information on the prognosis of their disease," the authors wrote.
"Hypothetically, a multifactorial approach could be applied to eventually come up with a formula that would allow a more precise prognosis of olfactory function. Especially since therapeutic options in patients with olfactory loss are limited, at present, this type of information is of high clinical significance."
SOURCE: Journal of the American Medical Association: Archives of Otolaryngology-Head & Neck Surgery
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