Results
All patients were classified as anosmic on the olfactory function test (Figure 2). Chemical and electro-gustatory test results indicated normogeusia.
MRI revealed no gross abnormalities in the brain parenchyma and a normal appearance of the pituitary gland, but the olfactory bulb could not be visualized bilaterally in 5 patients. Shallow olfactory sulci were observed in 4 patients and this suggested congenital agenesis of the olfactory bulb (Figure 3A). Relatively deep olfactory sulci were observed in 1 patient and it suggested early traumatic olfactory disorder (Figure 3B).
On functional MRI, 5 male patients showed no significant activation in primary olfactory cortex in both CIT and BME session. And no OERPs were recorded during their exam (Figure 4A). The one female patient showed mild activation in CIT session, but OERPs were not recorded (Figure 4B).
Follicle-stimulating hormone levels were within normal limits in 6 patients, as were luteinizing hormone levels, and testosterone levels. We therefore concluded that the patients’ anosmia was not associated with other structural and hormonal abnormalities such as Kallmann syndrome.
Four patients were confirmed as isolated congenital anosmia. And the olfactory sulci were relatively deep in MRI scan, so one male patient could not absolutely rule out early traumatic anosmia. One female patient seemed to be acquired anosmia.