Clinical observation of isolated congenital anosmia / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To introduce 8 patients with isolated congenital anosmia and to discuss the clinical manifestations, imaging characteristics and family characteristics of this rarely seen disorder.</p><p><b>METHODS</b>Eight patients with isolated congenital anosmia treated between April 2007 and April 2012 were reviewed retrospectively. There were 4 males and 4 females. A detailed medical history collection, physical examination, nasal endoscopy, T&T and Sniffin'Sticks subjective olfactory function tests, olfactory event-related potentials sinonasal computed tomography scan and sex hormones level monitoring were performed in all patients. Seven cases underwent magnetic resonance image of olfactory pathway examination.</p><p><b>RESULTS</b>All patients were anosmia without evidence of other defects. ENT physical examination, nasal endoscopy and computed tomography scan were normal except 4 cases with obvious nasal septum deviation, 2 cases with concha bullosa. Subjective olfactory test indicated all of them were anosmia. Olfactory event-related potentials were obtained in only 1 patient. Magnetic resonance imaging revealed the smaller or atrophy olfactory bulb and olfactory tract in five cases, the absence of olfactory bulbs and tracts in two case. A female patient did not have MRI examination because of wearing IUDs. Detection of 8 patients of sex hormones were normal. Family characteristics: 3 patients showed family inheritance pattern.</p><p><b>CONCLUSIONS</b>The diagnosis of isolated congenital anosmia should be based on chief complaint, medical history, physical examination, olfactory test, nasal endoscopy, olfactory testing, olfactory imaging and olfactory event-related potentials. Magnetic resonance image of olfactory pathway and olfactory event-related potentials have important value for the diagnosis. More attention should be paid to the genetic susceptibility of the family.</p>

Functional magnetic resonance imaging of brain activation in early period after olfactory adaptation / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To explore the brain activation before and in early period after olfactory adaptation using functional magnetic resonance imaging, and discuss the mechanisms of olfactory adaptation.</p><p><b>METHODS</b>Ten right-handed, normosmic subjects underwent 2 times of olfactory stimulation tasks with the interval of 20 minutes. The odorant used was isovaleric acid. The fMRI data was processed by the SPM5 software. Rating odor intensity and valence using visual analogue scale (VAS), and the results of 2 tasks were statistically analyzed.</p><p><b>RESULTS</b>There was no significant difference between 2 tasks on both intensity and hedonicity scores. In task 1, the brain activation in bilateral cerebellum, frontal (including orbitofrontal gyrus), insula, thalamus, cingulate gyrus, putamen, amygdala, piriform cortex, the left inferior parietal lobule, precentral gyrus, right hippocampus, pallidum, middle temporal gyrus, supramarginal gyrus. In task 2, only the right middle frontal gyrus activated, and the voxels decreased significantly. Paired t-test results showed that: (task1-task2) activated regions in left precentral gyrus, frontal lobe (including the orbitofrontal gyrus), insula, right superior temporal gyrus, cerebellum; (task2-task1) activation in the left inferior parietal lobule and right lingual gyrus.</p><p><b>CONCLUSIONS</b>The sensitivity of brain activation is still at a low level, when subjects had recovered from adaptation in subjective olfactory perception. Underwent repeated olfactory stimulation, second olfactory cortex plays less role on olfactory perception and advanced processing.</p>