Study of cochlear hydrops analysis masking procedure in patients with Meniere's disease and otologically normal adults.

BACKGROUND: The cochlear hydrops analysis masking procedure (CHAMP) is a new diagnostic technique for Meniere's disease (MD). But its value has not been well proven. This study aimed to evaluate the diagnostic value of CHAMP for MD. METHODS: CHAMP test was taken in three populations using the Auditory Evoked Potential system delivered by Bio-logic Systems Corporation: (1) otologically normal subjects; (2) patients clinically diagnosed with definite MD; (3) patients clinically diagnosed with probable and possible MD. RESULTS: According to the comparison between the normal and definite MD group, if the abnormal criterion of CHAMP was defined as latency delay less than 0.3 ms, then the corresponding sensitivity was only 52%. However, if the abnormal criterion was defined as latency delay between 0.6 and 3.8 ms, then a sensitivity of 93% and a specificity of 100% can be achieved. The complex amplitude ratio showed a significant overlap between normal and definite MD group. If the abnormal criterion was defined as a complex amplitude ratio less than 0.95, the corresponding specificity was only 50%. However, if the abnormal criterion was defined as less than 0.80, the corresponding sensitivity was 60%, and the specificity was 97%. If the abnormal criterion of CHAMP was defined as latency delay less than 0.6 ms or the complex amplitude ratio less than 0.80, CHAMP result can be obtained in all subjects with good sensitivity and specificity. CONCLUSIONS: CHAMP can differentiate patients with Meniere's disease from otologically normal subjects with high sensitivity and specificity. The recommended criterion of abnormal CHAMP was a latency delay less than 0.6 ms or a complex amplitude ratio less than 0.80.

[Analysis of clinical characteristics of partial olfactory dysfunction].

OBJECTIVE: To apply different types and concentrations of T&T olfactometer odorants to exam smell function and explore the clinical characteristics of partial olfactory dysfunction. METHODS: From March 2007 to May 2008, a total of 24 patients with olfactory dysfunction were examined by medical and psychiatric history enquiry, physical examination, smell testing and medical imaging. Olfactory function of each nostril was assessed separately by T&T olfactometer. The test contained five kinds of odorants at different concentrations. Recognition threshold (RT) scores for all five odorants and for each individual odorant were measured in all patients. RESULTS: Among them, total RT scores were normal while single odorant testing yielded only significant higher RT scores for one or two odorants. For patients who suffered partial olfactory dysfunction, 51.4% are for pleasant odors, while the rest are for unpleasant odors. CONCLUSION: Normal total RT scores and abnormal single RT scores of T&T olfactometer are present in partial olfactory dysfunction. As a special clinical manifestation of olfactory disorder, it may be easily ignored in smell testing.

[Application of unilateral olfactory testing and clinical analysis of unilateral hyposmia].

OBJECTIVE: To investigate whether patients presenting with self-reported olfactory disorders demonstrates significant side difference in odour recognition by measuring separately for each nostril. METHODS: One hundred and four patients with chief complaint of hyposmia were evaluated by medical history, physical examination, T&T olfactory testing and medical imaging. Smell was tested using T&T olfactometry in each nostril separately. RESULTS: Based on the history and results from the clinical examination, unilateral sinonasal diseases and abnormal nasal structure were excluded. In almost one eighth of all presenting patients (13.46%), a side difference was detected. Especially, six of the patients were identified with lateralized hyposmia. CONCLUSIONS: Olfactory testing could be performed in each nostril separately. The above findings suggested that testing each nostril separately was necessary so as not to miss unilateral hyposmia as a special clinical manifestation of olfactory disorder.

[Study of characteristic of the cochlear hydrops analysis masking procedure in normal adults].

OBJECTIVE: To study the characteristic of the cochlear hydrops analysis masking procedure (CHAMP) in normal adults, and to evaluate the diagnostic values of its parameters for membranous labyrinth hydrops. METHODS: Twenty otologically normal adults were recruited (male:female = 10:10), and their auditory brainstem responses (ABR) were obtained to six stimulus conditions using Bio-logic auditory evoked potential system: clicks presented alone (unmasked condition) and clicks presented with ipsilateral pink noise high-pass filtered at 8, 4, 2, 1, and 0.5 kHz respectively. RESULTS: The wave V latency of ABR to the high-pass masking pink noise clicks were longer than ABR to clicks alone. The latency delays of wave V for clicks presented with ipsilateral pink noise high-pass filtered at 8, 4, 2, 1, and 0.5 kHz compared to clicks alone were (0.30 ± 0.18), (0.97 ± 0.43), (1.65 ± 0.64), (3.21 ± 0.56), (4.66 ± 0.37) ms respectively. The complex amplitude ratio between ABR to click + 0.5 kHz high-pass noise and click alone was 0.95 ± 0.11. CONCLUSIONS: CHAMP is a promising diagnostic method for membranous labyrinth hydrops, and the latency delay of wave V might be used as the normal criterion. The specificity of the complex amplitude ratio need further evaluation in clinical work.

[Comparison of tone burst evoked auditory brainstem responses with different filter settings for referral infants after hearing screening].

OBJECTIVE: Auditory brainstem responses (ABR) evoked by tone burst is an important method of hearing assessment in referral infants after hearing screening. The present study was to compare the thresholds of tone burst ABR with filter settings of 30 - 1500 Hz and 30 - 3000 Hz at each frequency, figure out the characteristics of ABR thresholds with the two filter settings and the effect of the waveform judgement, so as to select a more optimal frequency specific ABR test parameter. METHODS: Thresholds with filter settings of 30 - 1500 Hz and 30 - 3000 Hz in children aged 2 - 33 months were recorded by click, tone burst ABR. A total of 18 patients (8 male/10 female), 22 ears were included. RESULTS: The thresholds of tone burst ABR with filter settings of 30 - 3000 Hz were higher than that with filter settings of 30 - 1500 Hz. Significant difference was detected for that at 0.5 kHz and 2.0 kHz (t values were 2.238 and 2.217, P < 0.05), no significant difference between the two filter settings was detected at the rest frequencies tone evoked ABR thresholds. The waveform of ABR with filter settings of 30 - 1500 Hz was smoother than that with filter settings of 30 - 3000 Hz at the same stimulus intensity. Response curve of the latter appeared jagged small interfering wave. CONCLUSIONS: The filter setting of 30 - 1500 Hz may be a more optimal parameter of frequency specific ABR to improve the accuracy of frequency specificity ABR for infants' hearing assessment.

[Clinical and magnetic resonance imaging characteristics of isolated congenital anosmia].

OBJECTIVE: To report a series of patients with isolated congenital anosmia and summarize their clinical and magnetic resonance imaging (MRI) characteristics. METHODS: Twenty patients with isolated congenital anosmia were reviewed retrospectively. A thorough medical and chemosensory history, physical examination, nasal endoscopy, T&T olfactory testing, olfactory event-related potentials, sinonasal computed tomography scan and magnetic resonance image of olfactory pathway were performed in all patients. RESULTS: Neither ENT physical examination nor nasal endoscopy was remarkable. Subjective olfactory testing indicated all of them were of anosmia. No olfactory event-related potentials to maximal stimulus were obtained. Computed tomography scan was normal. MRI revealed the absence of olfactory bulbs and tracts in all cases. And hypoplasia or aplasia of olfactory sulcus was found in all cases. All the patients had normal sex hormone level. CONCLUSION: The diagnosis of isolated congenital anosmia is established on chief complaints, physical examination, olfactory testing and olfactory imaging. MRI of olfactory pathway is indispensable.

Discordance between olfactory psychophysical measurements and olfactory event related potentials in five patients with olfactory dysfunction following upper respiratory infection.

BACKGROUND: Subjective olfactory tests are easy to perform and popularly applied in the clinic, but using only these, it is difficult to diagnose all disorders of the olfactory system. The olfactory event related potentials technique offers further insight into the olfactory system and is an ideal objective test. This analysis was of subjective and objective data on the olfactory function of twelve patients with loss of smell associated with an upper respiratory infection (URI). METHODS: We tested the twelve patients with URI induced olfactory loss by medical history, physical examination of the head and neck, olfactory tests and medical imaging. Olfactory function was assessed by Toyota and Takagi olfactometry including olfactory detection and recognition thresholds and olfactory event-related potentials (OERPs) recorded with OEP-98C Olfactometer. RESULTS: An unusual phenomenon was observed in five patients in whom the subjective detection and recognition thresholds were normal, while the expected OERPs were not detectable. CONCLUSIONS: We suggest that the discordance between olfactory psychophysical measurements and OERPs might be the results of abnormal electrophysiology related with olfactory neuropathy caused by viral URI. In addition, the measurement of OERPs might play a significant role in evaluating olfactory dysfunction.

Gene expression profiles in the olfactory bulb from a rat model of Alzheimer's disease.

Abnormalities and impaired functions of the olfactory system have been reported in Alzheimer's disease (AD), and these changes may appear much earlier than other clinical symptoms of AD. However, little is known about these abnormalities at the level of gene expression. In this study, we investigated alterations of expression of 22,012 genes in the olfactory bulbs of a rat model of AD by using a microarray approach. The rat model was produced by intracerebroventricular injection of amyloid-beta(25-35), which demonstrated pathological changes in olfactory bulbs and memory impairment in the Morris water maze test. We found that expression of 811 genes among the 22,012 genes was altered by more than 1.5-fold in the amyloid-beta-injected rats as compared with control injected rats. We analyzed the distribution of the 811 altered genes according to the Affymetrix criteria and found that the majority of these genes were related to cellular processes, binding, and enzyme activities. The alterations of three of these genes, i.e., calcineurin, olfactory receptor, and protein kinase C, were also confirmed by RT-PCR and Western blots. These studies provide new insight into the abnormalities of the olfactory system in AD and might help to further the understanding of the molecular mechanisms of AD.

[Olfactory functional magnetic resonance imaging with modified OEP-98C olfactometer and event-related design].

OBJECTIVE: To explore the feasibility of functional magnetic resonance imaging (fMRI) in analysis of olfaction function with modified OEP-98C olfactometer and event-related design. METHODS: Six young right-handed men underwent olfactory fMRI with event-related design. OEP-98C olfactometer was modified to accommodate MR environment. There were 2 types of tasks in the experiment. In one task, only isoamyl acetate was used as odorant. In the other task, to avoid possible decreased olfactory attention, vanillin was given before each presentation of isoamyl acetate. RESULTS: In both tasks, uniform activation in piriform cortex and secondary olfactory cortexes was determined. The activation of piriform cortex was not significantly different between the two tasks (P > 0.01). CONCLUSIONS: With isoamyl acetate as odorant, modified OEP-98C olfactometer, and event-related design, olfaction fMRI can depict cortex activation at primary and secondary olfactory cortex. Applying other odorant with similar quality to avoid olfactory attention decrease can not promote depiction of activation in primary olfactory cortex.

[MRI features of olfactory bulb volume in healthy middle and old-aged persons.].

OBJECTIVE: To investigate the differences of olfactory bulb (OB) volumes between younger and older, male and female, left-side and right-side in healthy middle and old-aged persons by MRI. METHODS: Ninety five healthy middle and old-aged volunteers (male:female = 45:50) were divided into 2 groups, group one included persons aged from 50 to 69, group two included persons elder than 70. The left-side, right-side and both-side volumes of OB, the volumes of brain and the ratio of OB/brain were measured by MRI. RESULTS: (1) The left-side and both-side volumes of OB (x(-) +/- s), the volumes of brain [(39.89 +/- 8.7) mm(3), (81.70 +/- 16.8) mm(3) and (1281.86 +/- 140.2) cm(3)] in 50 - 69 years old group were respectively larger than those in >/= 70 years old group [(34.45 +/- 10.4) mm(3), (72.10 +/- 19.3) mm(3) and (1165.77 +/- 165.3) cm(3)], and the differences reached statistical significance (t were respectively 2.649, 2.449, 3.516, all P < 0.05). There were no significant differences of right-side OB volumes and the ratio of OB/brain between 50 - 69 years old group and >/= 70 years old group (t were respectively 1.904, 0.616, each P > 0.05). (2) The male's OB volumes of left-side, right-side and both-side, the brain volumes and the ratio of OB/brain were respectively larger than females', and the differences reached statistical significance (t were respectively 4.461, 3.630, 4.399, 3.800, 2.400, all P < 0.05). (3) The right-side OB volumes were larger than left-side's and significant differences were found in female group, 50 - 60 years old group and >/= 70 years old group (t were respectively 2.732, 2.117, 3.516, all P < 0.05). There were no significant differences of OB volumes between left-side and right-side in female (t = 2.649, P = 0.110). The ratio of right-side OB/brain were larger than the ratio of left-side's and the differences reached statistical significance (t = 3.183, P = 0.002). CONCLUSIONS: MRI could be used to measure the volume of OB. The older the people, the smaller the OB volumes. There was no influence of age on the ratio OB/brain. The OB volumes of right-side were larger than those of left-side. The OB volumes of male were larger than those of female.

[Olfactory event-related functional magnetic resonance imaging in young adults with normal sense of smell and anosmia patients].

OBJECTIVE: To explore the brain activation mapping following odor presentation with event -related functional magnetic resonance imaging. METHODS: Ten healthy young volunteers with normal sense of smell and 5 anosmia patients, all right-handed, underwent routine otorhinolaryngological examination and T&T subjective smelling test. Odorant isoamyl acetate was delivered by olfactometer synchronously with inspiration birhinally for 10 times with the interstimulus interval of 60 seconds. Functional magnetic resonance imaging (fMRI) based on the blood-oxygen-level dependent effect was carried out on a 3.0 T scanner, using gradient-recalled echo and echo-planar imaging technique, and the image data were analyzed with SPM2 software. RESULTS: Functional activations were found in the volunteers with normal sense of smell, but not in the patients with anosmia. The activation regions were present in the orbitofrontal gyrus, anterior cingulate gyrus, piriform cortex, insular gyrus, amygdala, thalamus, basal nuclei, temporal gyrus, and frontal gyrus. There were more active regions in the right hemisphere than in the left hemisphere, and there were 314 and 57 active voxels in the right and left hemispheres respectively. CONCLUSION: Olfactory event-related fMRI is an objective measurement of olfaction, and has potential clinical application value.

[Posttraumatic anosmia: olfactory event related potentials and MRI evaluation].

OBJECTIVE: Using olfactory event related potentials (OERP) and magnetic resonance to evaluate olfactory function in patients with posttraumatic anosmia. METHODS: Twenty four patients with posttraumatic anosmia were reviewed retrospectively. A thorough medical history, physical examination, nasal endoscopy, T&T olfactory testing, olfactory event-related potentials, brain computed tomography scan and magnetic resonance image of olfactory pathway were performed in all patients. RESULTS: Subjective olfactory testing indicated 20 of 24 patients were birhinal anosmia, 2 with right nostril anosmia and left impairment, 2 with left anosmia and right normal. No OERP were obtained in 24 (20 were birhinal, 4 was monorhinal), except 4 cases with single nostril. Magnetic resonance imaging revealed the injures to the olfactory bulbs (100%), rectus gyrus (91.7%), orbital gyrus (67%), olfactory tracts (8%) and temporal lobes (8%). CONCLUSIONS: OERP can objectively evaluate posttraumatic olfactory function, and magnetic resonance of olfactory pathway can precisely identify the location and extent of injures.

[Clinical analysis of primary facial nerve neuroma].

OBJECTIVE: To analyze the clinical features of facial nerve neuroma about its diagnosis and management. METHODS: Ten patients with facial nerve neuroma were analyzed retrospectively from February 1993 to August 2005. The period of follow-up varied from 1.5 years to 10 years (mean 5 years). Facial nerve function was evaluated with House-Brackmann grading system. RESULTS: The patients complained of facial paralysis in 7 cases, otitis media in 1 case, a mass in parotid gland in 1 case and a mass on the side of the orbital on face in 1 case. Seven patients were undergone either CT scan or MRI or both. Image studies revealed mass located along the facial nerve course from the nerve endings to the intracranial parts. All the patients accepted the surgery. Intraoperative findings showed that the tumor location matched the image findings. Postoperative pathological diagnosis demonstrated 8 Schwannoma, 2 neurofibroma. There was partial tumor resection in 1 patient accepted and his nerve function was unchanged. Four patients were undergone facial nerve graft but 1 case failed while facial nerve function was improved in 3 other patients. Two patients underwent tumor resection while the continuity of facial nerve was preserved as result their facial nerve function improved respectively. No facial nerve reconstruction was done on other 2 patients. CONCLUSIONS: Multiple origins of facial nerve neuroma were noted and the most common system was facial nerve palsy. The decision on how to treat these patients should be individualized and based on initial facial function, growth rate, surgical experience and informed patient consent. The more effective methods need being seeked for the management of facial nerve neuroma.