上呼吸道感染后嗅觉障碍患者化学感觉功能评估

目的:观察上呼吸道感染后嗅觉障碍（post-viral olfactory dysfunction,PVOD）患者的嗅觉功能、鼻内三叉神经功能和味觉功能变化,探讨PVOD患者化学感觉功能变化的相关性。方法:回顾性分析2019年1—12月在北京安贞医院耳鼻咽喉头颈外科嗅觉味觉中心就诊的PVOD患者42例,其中男20例,女...     

嗅觉功能障碍患者鼻内三叉神经功能的评估

目的探讨嗅觉障碍患者鼻内三叉神经功能的改变。方法 303例受试者中健康人100名,嗅觉功能障碍患者203例,分别采用T&T嗅觉计定量检查法(T&T)、嗅觉事件相关电位(olfactory event-related potentials,oERPs)和三叉神经事件相关电位(trigeminal event-related potentials,tERPs)进行嗅觉和三叉神经功能检测。结果 T&T识别域结果表明嗅觉功能障碍患者跟健康人比较差异有显著性意义(P<0.05)。oERPs和tERPs结果显示嗅觉功能障碍患者跟健康人比较N1、P2波潜伏期延长,差异有显著性意义(P<0.05)。结论嗅觉功能障碍患者多伴有三叉神经敏感性的下降,青年患者下降尤为显著,其下降程度与性别关系不大。研究证实两种化学感受系统之间存在联系,联合检测可有助于临床的诊断和治疗。     

Are there sex-related differences in responses to repetitive olfactory/trigeminal stimuli?

Sex differences in olfactory sensitivity have been reported since the late 1800’s with women typically outperforming men on tests of odor detection, discrimination or identification. It is not known whether women adapt differently than men to olfactory and trigeminal stimuli. Seventeen healthy volunteers participated (9 female, 8 male, mean age 22 years) in the study. As established by an odor identification test (UPSIT, score ≥38) all subjects had normal olfactory function. Event-related potentials (ERPs) were recorded in response to olfactory (25% v/v phenyl ethyl alcohol) and trigeminal (44% v/v CO₂) stimuli using a computer controlled olfactometer (flow 8 L/min; stimulus duration 200 ms). Stimuli were applied at four intervals (5, 10, 20, and 60 s). Amplitudes and latencies of ERP peaks P1, N1, and P2 were measured. Stimulus intensity also rated using visual analogue scales subjects. When compared to phenyl ethyl alcohol, the slightly more intense CO₂ produced larger amplitudes and shorter latencies. Both, ratings and ERP amplitudes P2 decreased with decreasing interval between stimuli. Responses to the trigeminal and olfactory stimuli changed similarly in relation to repetitive stimulation. Women had larger ERP amplitudes P2. No sex-related difference for ratings and ERP in relation to repeated stimulation amplitudes was observed. Although women exhibit larger ERP amplitudes to chemosensory stimuli compared to men, the present data indicate on both psychophysical and electrophysiological levels that there is no major difference between young, healthy men and women in relation to short-term adaptation to suprathreshold chemosensory stimulation.     

Trigeminal event-related potentials in patients with olfactory dysfunction

OBJECTIVE: There are mutual interactions between the olfactory and trigeminal systems. The purpose of this study was (1) to assess trigeminal sensitivity using chemosensory event-related potentials (CSERPs) in patients with olfactory dysfunction and (2) to evaluate whether trigeminal ERPs were different with regard to the presence or absence of olfactory ERPs. MATERIALS AND METHODS: Prospective study of 60 patients who presented with olfactory dysfunction (postinfectious olfactory loss: n = 19, posttraumatic olfactory loss: n = 28, and olfactory loss due to idiopathic, or toxic causes: n = 13). All patients were extensively evaluated with an orthonasal olfactory test based on the "Sniffin' Sticks". In addition, chemosensory ERPs were recorded in response to olfactory and trigeminal stimulation. RESULTS: Olfactory/trigeminal ERPs were recorded in 25/60 patients, respectively. Patients with no detectable olfactory ERPs, considered as severely affected, demonstrated an altered trigeminal sensitivity as indicated by an increase in P2 latencies and a decrease in both, P2 and N1-P2 amplitudes compared to patients with detectable olfactory ERPs. A regression analysis showed a negative relation between P2 latencies and the "Sniffin' Sticks"score (r = -0.46, p < 0.001). CONCLUSIONS: Patients with severe olfactory dysfunction demonstrated decreased trigeminal sensitivity as indicated by electrophysiological measures. This study supports the idea of interactions between the chemical senses. Whether altered responses to trigeminal stimulation may be used as a prognostic measure related to recovery from olfactory loss remains to be demonstrated.     

Decreased trigeminal sensitivity in anosmia

The present study aimed to investigate intranasal trigeminal sensitivity in a large sample of patients with anosmia due to different etiologies. We investigated the trigeminal detection threshold for formic acid in healthy controls (n = 96) and patients with anosmia due to head trauma (n = 18) or sinonasal disease (n = 54). Anosmics exhibited higher thresholds compared with normosmics (p < 0.001). In addition, thresholds were found to be higher in patients with posttraumatic anosmia compared to anosmics with sinonasal disease (p < 0.001). The data indicate that (1) loss of olfactory sensitivity in humans may be associated with a decreased sensitivity towards trigeminal stimuli and (2) alteration of intranasal trigeminal function is stronger in patients with posttraumatic anosmia compared to patients with sinonasal disease. This may have implications for the medicolegal investigation of anosmic patients where trigeminal stimuli are frequently used to assess the patient's response bias.     

Gender difference in Chinese adults with post-viral olfactory disorder:a hospital-based study

Conclusions: This hospital-based study found a gender differences in Chinese subjects with post-viral olfactory disorder (PVOD). Women appear to face higher susceptibility to PVOD, a finding that appears to be magnified with age and duration of olfactory loss.

Objectives: PVOD is one of the most common reasons for acquired olfactory dysfunction, but there is little data in Chinese populations. We analyzed Chinese subjects with PVOD in order to determine demographic risk factors and clinical features in this major population group.

Methods: Data from 143 consecutive subjects with PVOD and 117 subjects with other olfactory disorders (controls) were analyzed. This study examined age, duration, and severity of olfactory loss, and compared the differences of subjective and objective olfactory function tests between two groups, using Sniffin’ Sticks, Olfactory Event Related Potential (OERP), and olfactory pathway MRI.

Results: There were more women in the PVOD group compared to controls (p?p?=?0.027), and the proportion of women with PVOD increased with the duration of olfactory loss (p?=?0.032). There were no differences in the prevalence of abnormal OERP between two groups, although the female-to-male ratio was higher in the PVOD group (p?=?0.041). Women with PVOD were less likely to have olfactory pathway abnormalities by MRI compared to controls (p?相似文献   

Intranasal trigeminal sensitivity in subjects with allergic rhinitis

Trigeminal nerve endings of the human nasal mucosa are activated by chemical, physical or thermal stimuli. Activation of these A_delta and C fibers can be quantified through the recording of chemo-somatosensory event-related potentials (ERP). The aim of this study was to investigate whether allergy-related activation of trigeminal nerve endings leads to changes in their responsiveness to intranasal trigeminal stimulation. Gaseous carbon dioxide (CO₂) stimuli were applied in three sessions (baseline, after NaCl solution and after allergen application) to the nasal mucosa of 13 subjects with allergic rhinitis. Chemo-somatosensory ERP were recorded, and subjects rated the intensity of rhinitis symptoms. Administration of allergen produced a significant shortening of chemo-somatosensory ERP peak latencies P1 and N1. Observed changes of latencies were in line with rhinitis symptoms subjects indicated during the session. In addition, there was a negative relation between the general symptom score and ERP peak latencies, obtained both at baseline and after allergen exposure. In conclusion, it is hypothesized that in patients suffering from allergic rhinitis, nasal itching and sneezing after allergen exposure are, at least in part, clinical correlates of the activation of trigeminal nerve endings due to local inflammatory mechanisms. The correlations between ERP latencies and the patients symptoms indicate that ERP latencies may possess a predictive value of the subjects responsiveness to allergens.     

Olfactory function assessed with orthonasal and retronasal testing, olfactory bulb volume, and chemosensory event-related potentials

OBJECTIVE: To investigate whether differences in olfactory function between healthy individuals and patients with olfactory loss could be detected by various diagnostic tests. DESIGN: Psychophysical testing of orthonasal and retronasal olfactory functions, magnetic resonance imaging of olfactory bulb (OB) volume, and chemosensory event-related potential (ERP) measurement performed between January 1, 2005, and October 31, 2005. SETTING: Academic tertiary referral medical center. PATIENTS: Eleven healthy individuals with normal olfactory function (NL) and 11 patients with nasal polyposis (NP), 11 with posttraumatic olfactory loss (PT), and 11 with postinfectious olfactory loss (PI) were included in this study. MAIN OUTCOME MEASURES: Orthonasal and retronasal olfactory test results, magnetic resonance imaging-based OB volume, and ERPs to both olfactory and intranasal trigeminal stimulation. RESULTS: Orthonasal and retronasal testing revealed that NL individuals had higher scores than patients with NP, PT, or PI. Retronasal scores were higher in NP patients compared with PT and PI patients. The OB volumes were higher in NL individuals compared with NP, PT, and PI patients. The OB volumes in PT patients were significantly lower than those from NP and PI patients. Olfactory ERPs were different between NL individuals and NP, PT, and PI patients, and trigeminal ERPs were significantly different when comparing NL individuals with NP patients. For the entire cohort, a significant correlation was found between orthonasal testing and OB volume, between retronasal testing and OB volume, and between both orthonasal and retronasal testing and olfactory ERP amplitudes. Olfactory ERPs were recorded in the 11 NL individuals and in 3 NP, 3 PT, and 4 PI patients, defined as responders. Orthonasal and retronasal test scores, OB volume, and olfactory ERPs were significantly larger in responders compared with nonresponders. CONCLUSIONS: Significant differences in various tests that evaluate olfactory function were detectable in a cohort of NL individuals and NP, PT, and PI patients. This finding suggests that these diagnostic tools provide information in terms of the clinical assessment of olfactory function. Future studies will investigate their combined use in terms of the prognosis of olfactory function in patients with olfactory loss.     

Chemosensory event-related potentials to trigeminal stimuli change in relation to the interval between repetitive stimulation of the nasal mucosa

Event-related potentials (ERPs) to olfactory and trigeminal stimuli have been used commonly to evaluate chemosensory dysfunction. The aim of the present study was to investigate how ERPs could be modified by repetitive stimulations of the intranasal trigeminal nerve using 52% v/v CO₂ stimuli for 200 ms periods. Nine subjects were exposed to 6 sessions each during which trains of 16 stimuli were applied. The interval between stimuli was constant for each experiment, but varied between experiments (10, 20, 30, 40, 60, and 90 s). Trigeminal ERPs were obtained from three positions on the skull. Both intensity ratings and ERP amplitudes decreased as the interstimulus interval (ISI) shortened. Specifically, ratings and response amplitudes were most strongly reduced by approximately 30–50% at the shortest ISI used (10 s) and were largest at an ISI of 90 s. The decrease of amplitudes was strongest for the P₄₆ amplitude. Our findings suggest that this may be the result of both habituation and stimulus predictability. We hypothesize that the ISI dependence of chemosensory ERPs may also be a function of an interaction between A_delta and C fibers. Received: 17 April 1998 / Accepted: 29 July 1998     

Intranasal trigeminal sensitivity: measurements before and after nasal surgery

Nasal surgeries constitute an extensive manipulation of the nasal mucosa and therefore of structures related to trigeminal and olfactory sensitivity. While olfactory changes due to nasal surgery are relatively well investigated, there are only very few studies regarding trigeminal sensitivity. Aim of the present study was to investigate sensory changes after nasal surgery with special regard to the trigeminal sensitivity. In 38 patients prior to and around 12 weeks after nasal surgery the following psychophysical measures were performed: odor identification, odor discrimination, phenyl ethyl alcohol odor threshold, sensitivity to trigeminal stimuli, trigeminal detection thresholds and trigeminal pain thresholds. These results were compared to those of a control group (43 healthy volunteers). Psychophysical olfactory and trigeminal testing showed no major changes in patients after surgery compared to the control group. Independent from the time of measurement higher trigeminal detection thresholds were found in patients compared to healthy subjects, meaning that trigeminal thresholds were already increased before surgery. The present study revealed a decreased trigeminal sensitivity in patients already before surgery. It may be hypothesized that patients also exhibit a decreased sensitivity for nasal airflow, which may also contribute to the patients’ impression of impaired nasal breathing.     

Test-retest variability of auditory event-related potentials

Auditory event-related potentials (ERP, P3 components) were recorded from normal young adult subjects (17 to 37 yr) during two sessions scheduled 1 to 2 weeks apart. The test-retest intrasubject variability and the intersubject variability of the latency and amplitude values of components N1, P2, and P3 were investigated and analyzed. Between subjects, there was no evidence of systematic age-related changes of component latencies and amplitudes: the latency of P2 came closest to exhibit such an effect. Within subjects, there were no statistically significant changes of component latencies and amplitudes between test and retest, although ERP component latencies tended to be reduced on retest, especially the latency of P3.     

Auditory lexical-semantic processing impairments in aphasic patients reflected in event-related potentials (N400)

Objective: Event-related potentials (ERPs) and response latencies were recorded from aphasic subjects with auditory language processing impairments and age-matched normal controls, while performing a lexical-semantic evaluation task, aiming at clarifying whether ERPs could be a reliable measure for indicating language impairments in aphasic patients. Methods: The stimuli were 50 pairs of spoken words (prime word–target word): 25 pairs, which were semantically and/or associatively related to each other, and 25 pairs which were not. The subjects pressed a switch in response to the presentation of target words semantically related to the prime words. The ERP component analyzed in this study was N400. Results: With the performances, the response latencies were longer in the aphasic subjects than in the normal controls. With the ERPs, onset latencies of N400 were shifted behind in the aphasic patients compared to the normal controls. For the aphasic patients, there were correlations between the size of N400 and performances in auditory comprehension evaluated in the aphasia test. Conclusion: The conclusions drawn from the results are that not only response latencies in the lexical-semantic judgement task, but also N400 effects, may be a reliable clinical measure of the severity of even mild lexical-semantic impairments in aphasic patients.     

Loss of trigeminal sensitivity reduces olfactory function

The trigeminal and olfactory nerves share overlapping innervation areas in the nasal cavity and seem to work in an interactive way. Loss of olfactory function leads to a decreased trigeminal sensitivity, as shown in anosmic subjects. To report the impact of disturbed trigeminal sensitivity on the olfactory function, we present a patient with unilateral loss of trigeminal function resulting from a meningeoma. Thresholds to a selective olfactory stimulus were elevated by a factor of 64 on the affected side. Recordings of event-related potentials in response to olfactory stimuli showed a significantly reduced response on the affected side. This report indicates that loss of trigeminal function may affect the sense of smell.     

Identification of viruses in patients with postviral olfactory dysfunction

OBJECTIVE: Causative viruses of postviral olfactory dysfunction (PVOD) have not yet been identified. The aim of this study was to investigate causative viruses in patients with PVOD. STUDY DESIGN AND METHODS: Nasal discharge was collected from 24 patients with PVOD. We investigated the presence of 10 viruses in nasal discharge and examined the time course, with regard to changes in olfactory dysfunction and nasal obstruction in patients with PVOD, using questionnaires, acoustic rhinometry, and olfactory tests. RESULTS: Rhinoviruses were detected in 10 patients by electrophoresis. Rhinoviruses were also confirmed in four patients by nucleotide sequences. Viral serotypes were identified to be human rhinovirus (HRV)-40, HRV-75, HRV-78, and HRV-80. One of the four patients complained of anosmia, whereas another complained of dysosmia. Olfactory testing did not show significant improvement at 4, 8, 11, and 24 weeks after the first visit in the four patients, although results of acoustic rhinometry significantly improved. Two of the four patients complained of olfactory dysfunction even 6 months after the first visit. Coronavirus and parainfluenza virus were detected in one patient each, and Epstein-Barr viruses were detected in three patients. CONCLUSIONS: This study for the first time detected rhinovirus, coronavirus, parainfluenza virus, and Epstein-Barr virus in nasal discharge of patients with PVOD. Furthermore, the present study suggests that rhinoviruses can cause olfactory dysfunction through mechanisms other than nasal obstruction and that rhinoviruses can induce various severities and different time courses of olfactory dysfunction.     

Effects of sensorineural hearing loss and personal hearing AIDS on cortical event-related potential and behavioral measures of speech-sound processing

OBJECTIVE: To systematically investigate the combined effects of sensorineural hearing loss and prescribed personal hearing aid(s) on cortical event-related potentials (ERPs) (waves N1, MMN, N2b, and P3b) and their related behavioral measures of discrimination (d-prime sensitivity and reaction time) to the speech sounds /ba/ and /da/ presented at 65 and 80 dB peak-to-peak equivalent SPL. DESIGN: Cortical ERPs were recorded to /ba/ and /da/ speech stimuli presented at 65 and 80 dB peak-to-peak equivalent SPL from 20 normal-hearing adults and 14 adults with sensorineural hearing losses. The degree of sensorineural impairment at 1000 to 2000 Hz ranged from moderate losses (50 to 74 dB HL) to severe-profound losses (75 to 120 dB HL). The speech stimuli were presented in an oddball paradigm and cortical ERPs were recorded in both active and passive listening conditions at both stimulus intensities. The adults with hearing impairments were tested in the unaided and aided conditions at each stimulus intensity. Electroacoustic and real-ear testing was performed on each subject's hearing aid(s) before electrophysiology testing to ensure that the hearing aids were functioning at the time of testing. RESULTS: The use of personal hearing aids substantially improved the detectability of all the cortical ERPs and behavioral d-prime performance scores at both stimulus intensities. This was especially true for individuals with severe-profound hearing losses. At 65 dB SPL, mean ERP amplitudes and d-prime sensitivity scores were all significantly higher or better in the aided versus unaided condition. At 80 dB SPL, only the N1 amplitudes and d-prime sensitivity scores were significantly better in the aided condition. Even though the majority of the hearing-impaired subjects showed increased amplitudes, decreased latencies, and better waveform morphology in the aided condition, the amount of response change (improvements) seen in these measures showed considerable variability across subjects. When compared with the responses obtained from the normal-hearing subjects, both hearing-impaired groups had significantly prolonged aided RT latencies at both stimulus intensities and N2b latencies at the higher stimulus intensities. CONCLUSIONS: These results suggest that hearing-impaired individuals' brains process speech stimuli with greater accuracy and in a more effective manner when these individuals use their personal hearing aids. This is especially true at the lower stimulus intensity. The effects of sensorineural hearing loss and personal hearing aids on cortical ERPs and behavioral measures of discrimination are dependent on the degree of sensorineural loss, the intensity of the stimuli, and the level of cortical auditory processing that the response measure is assessing. The possible clinical significance of these cortical ERP and behavioral findings is discussed.     

Chemosensory function assessed with psychophysical testing and event-related potentials in patients with atrophic rhinitis

Atrophic rhinitis (AR) is a chronic inflammation of the nose characterized by an atrophy of the nasal mucosa. This is typically associated with an impaired sense of smell and a subjective sensation of poor nasal breathing. The aim of this study is to assess chemosensory function in patients suffering from AR using psychophysical testings and event-related potentials (ERP) responses. A cohort of nine patients was extensively studied. Eight out of nine had secondary AR sequela of a bilateral total inferior turbinectomy whereas one patient had a primary AR. All the patients had a clinical evaluation using Sniffin’ Sticks test and a retro-olfaction test and an electrophysiological evaluation based upon ERPs obtained after both olfactory and trigeminal stimuli. All the patients complained of a poor nasal breathing and presented a distortion of the chemosensory function. Actually, the orthonasal psychophysical testing showed that four patients out of nine had anosmia, three out of nine had hyposmia and two out of nine were normosmic. All the patients demonstrated retro-olfaction scores inferior to the normal values. The chemosensory ERP showed that seven patients had no olfactory response whereas six had no trigeminal response. Four patients had neither olfactory nor trigeminal ERP response. In conclusion, this study demonstrates that most patients with AR secondary to a total bilateral inferior turbinectomy have a reduction of the chemosensory function measured objectively by psychophysical testings and ERP. Moreover, the trigeminal responses were absent in all the cases.     

Subjective changes in nasal patency after chewing a menthol-containing gum in patients with olfactory loss

Conclusion: The subjective increase in nasal patency after oral menthol application depends on olfactory function. In patients with relatively low olfactory sensitivity, this effect is small or absent. It was hypothesized that this may also modulate the sensation of nasal blockage. Objective: Menthol stimulates the nasal trigeminal nerve, resulting in a subjectively increased nasal airflow and patency without objectively measurable changes. Patients suffering from olfactory impairment also express a reduced nasal trigeminal sensitivity. The aim of this investigation was to examine the effect of menthol on nasal patency ratings in a group of patients suffering from olfactory dysfunction. Methods: A group of 92 patients with olfactory impairment was included in this study. Olfactory function was assessed using the ‘Sniffin’ Sticks.’ Patients were instructed to chew a menthol-containing gum for 30 s, after which they rated the change in nasal patency on a categorical scale. Results: Patients who rated the change in nasal patency as pronounced scored higher on the Sniffin’ Sticks olfactory test compared to patients who experienced little or no change in nasal patency after chewing the menthol-containing gum. On average, similar changes could be observed for all etiologies of olfactory impairment included in this study.     

Olfactory and intranasal trigeminal event-related potentials in anosmic patients

The aim of this study was to investigate the usefulness of chemosensory event–related potentials (CSERPs) in response to both olfactory and intranasal trigeminal stimulation in the diagnosis of anosmia. Forty-four patients participated. Gaseous CO₂ was used for trigeminal stimulation, vanillin and H₂S were used as olfactory stimulants. Event-related potentials to olfactory stimuli could not be obtained in any of the anosmic patients, indicating the complete loss of the sense of smell. However, all patients responded to stimulation of the trigeminal nerve with CO₂. These data clearly demonstrate the clinical significance of CSERPs in the assessment of anosmia.     

Differences in anosmic and normosmic group in bimodal odorant perception: a functional- MRI study

So-called bimodal odorants are able to stimulate the intranasal trigeminal system at relatively low concentrations. Using them as stimuli, the current study focused on the interaction between the olfactory and trigeminal systems at a cerebral level. In the experiment, menthol was used at two concentrations, low and high, and these were delivered to two groups of subjects, a healthy control group and an anosmic group who were unable to perceive smells. A computer-controlled olfactometer based on principles of air-dilution was used to deliver the stimuli, while the brain functions were assessed by a functional magnetic resonance imaging (fMRI) technique. SPM5 was used for data analysis. The results showed that normosmic subjects exhibited activation in the anterior cingulate cortex (ACC) and posterior cingulate cortex (PCC), prefrontal cortex (PFC), and cerebellum. Whilst anosmic subjects activated the same area inside the anterior cingulate; moreover a cluster of activation was found in the left parahippocampal gyrus. In controls, an effect of stimulus intensity was localized between the anterior cingulated, the medial frontal gyrus and the cerebellum; such areas could not be found in anosmic subjects. These results suggest that the olfactory system modifies trigeminally mediated information causing an evident effect in the differentiation between stimulus intensities.