听性稳态反应应用于婴幼儿听力评估的现状

刺激速率为70～110 Hz的听性稳态反应(auditory steady-state response, ASSR)(亦称为80 Hz)最近倍受听力学工作者特别是小儿听力学工作者的关注,设备制造商也正在推销其产品.本文回顾了ASSR的技术、应用基础,并总结了其应用于婴幼儿听力评估的现状.文中斜体字为基本原则.详细的ASSR方法学、正常值以及一些ASSR研究结果请参阅Picton(2003)的综述.ASSR并不是一个新发现的听觉反应,1960年Geisler就从人类头颅上记录到了该反应;以后研究者又记录到了短声、正弦调制波以及方波调制波所诱发的反应.Galambos等在1981年发表的有关40 Hz事件相关电位将ASSR引入听力领域.不同刺激速率的ASSR的产生部位是不同的,40 Hz的ASSR产生于皮层和脑干,而80 Hz的ASSR主要来源于脑干,而且很有可能它就是ABR的波Ⅴ,只是与ABR的刺激和记录方法不同而已.ASSR的重要特征之一就是在频域内分析的方法,通过计算位相相关性或刺激速率值处的信噪比,再根据统计学分析来判定反应的引出与否,这种客观性使ASSR显著优于ABR.ASSR的刺激信号最早是象ABR一样的短纯音信号,以后主要用调幅调制声,有时也加入10%～20%的调频调制,目前大多数设备都采用这一信号,最近一种新ASSR设备的缺省设置是5～8 ms的短音.ASSR的另一个重要特征是能够同时记录多个刺激声信号所产生的反应,这种多频刺激的方法能够同时记录双耳八个频率(每耳四个频率)的反应.研究证明只要各个信号的频率相距一个倍频程以上,强度在75 dB SPL以下,多个刺激声之间的干扰就很小或没有.不对称型的听力图、不同频率所产生的反应幅度的不同以及多频刺激方式所导致的各个频率反应幅度整体的下降延长了这种方法的测试时间,使其不如理想中的那么省时,但仍比单一刺激方式快2～3倍.80 Hz ASSR通常采用的是正弦调幅调制纯音,因为其特有的频率特异性而被认为是优于短纯音ABR的一个方面,但是声信号的频率特异性只是其中的一方面,还应考虑到耳蜗基底膜的部位特异性以及神经反应的特异性.研究证明ASSR的频率特异性与短纯音ABR是非常接近的.ASSR技术以飞快的速度发展,十年前还没有商用的设备,五年前只有两家,而目前至少有六种不同的设备.随着设备的增加,各个设备之间标准化的问题突显出来.有些设备有很浑厚的研究背景,而有些则没有,使用者应该根据设备的性能及临床资料而加以选择.关于80 Hz ASSR与行为听力测试相关性的研究很多,多为感音神经性聋成人或较大儿童,结果表明至少在该人群中ASSR的阈值能够很好地预测行为听力阈值.许多ABR与ASSR的比较研究声称ASSR比ABR能够更好地评估残余听力,也就是当受试者听力损失很重、ABR不能引出时,仍能够引出ASSR.尽管这一现象客观存在,但是还有一些其他需要考虑的影响因素,如:①所比较的信号在某一特定频率上的能量是不相等的,众所周知短声的能量分布频率范围很宽,其最大输出强度较ASSR信号小;②ASSR在高强度会有伪迹或非听性反应;③ASSR的长时强声刺激会导致耳蜗损害.因此需慎重对待这一问题.目前还没有关于传导性聋或混合性聋气导ASSR的研究,模拟传导性聋的研究表明气导ASSR阈值远高于行为听阈,而且ASSR骨气导差过大.骨导ASSR的研究显示听力正常婴幼儿各个频率的ASSR的阈值与成人显著不同.正常听力婴幼儿的短纯音ABR阈值以及诊断标准已经确立,而ASSR在这一方面的研究则显得不足,而且不同研究所采用的刺激(单频与多频)及记录(不同信噪比、噪声标准以及记录时间)方法不同,使这一形势更加恶化.综合不同调幅调制纯音ASSR的研究结果,正常听力婴幼儿在500、1 000、2 000及4 000 Hz的平均阈值分别为41、43、35和32 dB HL,如果转换为dB SPL则与短纯音ABR非常相似.如果以均值的90%～95%为可信区间,取二倍标准差,则诊断标准在500 Hz为60 dB HL,1 000、2 000及4 000 Hz为50 dB HL.关于感音神经性聋儿童ASSR的研究有很多,这种研究比较理想的方法应该将婴幼儿的ASSR阈值与行为听阈或短纯音ABR阈值相比较.遗憾的是多数研究都是短声ABR与ASSR的比较.总结以上工作发现,首先样本数量还很少,其次多数有方法学的缺陷,加之不同研究所采用的刺激和记录方法不同,临床资料就更加减少.最后还没有不同类型听力损失的婴幼儿ASSR的研究.总而言之,尽管ASSR在婴幼儿听力评估方面很有前途,但目前单独以此作为听力诊断的电生理方法还为时过早,还必须结合短纯音ABR,因为只有短纯音ABR才具有充足的基础、临床研究和明确的诊断标准,因而也是目前婴幼儿听力诊断电生理方法的金标准.根据上述回顾,ASSR在婴幼儿听力诊断的现状总结如下:①新的刺激及记录方法通常都没有经过同行审阅的临床科研为依据,特别是缺乏听力障碍婴幼儿的数据;②不同设备采用不同的刺激和记录方法,且缺少专业人员的评估;③不同的方法或设备层出不穷,缺乏标准化;④刺激声信号的校准问题以及ASSR与行为听力之间的关系问题还没有解决,各种设备采用不同的刺激和记录方法更加恶化了这一状况;⑤极重度聋者的ABR和ASSR的关系还有待于进一步研究;⑥听力损失儿童的ASSR与行为听力测试的关系的研究还很少,而且现有的大多数研究没有能够将ASSR与听力诊断的金标准--行为听力和/或短纯音ABR进行比较;⑦六个月以下婴幼儿的ASSR 研究还很少;⑧传导性聋或混合性聋成人和婴幼儿的研究还很少;⑨成人的骨导ASSR研究很少,还没有婴幼儿骨导ASSR的研究报道,也没有病理状态下成人或婴幼儿的骨导ASSR研究(极重度聋除外).如果上述问题得不到解决,ASSR技术就不能称为成熟.因为对于一个结果,无法准确地判定该阈值是正常还是升高.短纯音ABR的研究虽然尚需完善,但它已有非常多的研究背景和临床数据,能够提供气导和骨导听阈,是当前婴幼儿(特别是6个月以下儿童)听阈确定的首选方法.因此目前ASSR还需与短纯音ABR或行为听力测试结合使用. 80 Hz ASSR除了用于阈值的评估外,也可以用于阈上功能的评估,如单词识别或助听器效果的预估.结果 表明在正常或异常听力成人以言语调制声为信号,其识别阈与ASSR有显著相关性,它反映了较低水平的听觉处理能力.     

Development of EMPRO: A Tool for the Standardized Assessment of Patient-Reported Outcome Measures

Objective:  This study was aimed to develop a tool for the standardized assessment of patient-reported outcomes (PROs) to assist the choice of instruments.
Methods:  An expert panel adapted the eight attributes proposed by the Medical Outcomes Trust as evaluation review criteria, created items to evaluate them, and included a response scale for each item. A pilot test was designed to test the new tool's feasibility and to obtain preliminary information concerning its psychometric properties. The Spanish versions of five measures were selected for assessment: the SF-36 Health Survey, the Nottingham Health Profile, the COOP-WONCA charts, the EuroQol-5D, and the Quality of Life Questionnaire EORTC-QLQ-C30. We assessed the new tool's reliability (Cronbach's alpha and intraclass correlation coefficient [ICC]) and construct validity.
Results:  The new EMPRO (Evaluating the Measurement of Patient-Reported Outcomes) tool has 39 items covering eight key attributes: conceptual and measurement model, reliability, validity, responsiveness, interpretability, burden, alternative modes of administration, and cross-cultural and linguistic adaptations. Internal consistency was high (α = 0.95) as was interrater concordance (ICC: 0.87–0.94). Positive associations consistent with a priori hypotheses were observed between EMPRO attribute scores and the number of articles identified for the measures, the years elapsed since the publication of the first article, and the number of citations.
Conclusion:  A new tool for the standardized assessment of PRO measures is available. It has shown good preliminary reliability and validity and should be a useful aid to investigators who need to choose between alternative measures. Further assessment of the tool is necessary.     

Optimizing the sensitivity of the head thrust test for identifying vestibular hypofunction

BACKGROUND AND PURPOSE: The head thrust test (HTT) is used to assess the vestibulo-ocular reflex. Sensitivity and specificity for diagnosing unilateral vestibular hypofunction (UVH) in patients following vestibular ablation is excellent (100%), although sensitivity is lower (35%-39%) for patients with nonsurgically induced UVH. The variability of the test results may be from moving the subject's head outside the plane of the lateral semicircular canals as well as using a head thrust of predictable timing and direction. The purpose of this study was to examine sensitivity and specificity of the horizontal HTT in identifying patients with UVH and bilateral vestibular hypofunction (BVH) when the head was flexed 30 degrees in attempt to induce acceleration primarily in the lateral semicircular canal and the head was moved unpredictably. SUBJECTS: The medical records of 176 people with and without vestibular dysfunction (n=79 with UVH, n=32 with BVH, and n=65 with nonvestibular dizziness) were studied. METHODS: Data were retrospectively tabulated from a de-identified database (ie, with health information stripped of all identifiers). RESULTS: Sensitivity of the HTT for identifying vestibular hypofunction was 71% for UVH and 84% for BVH. Specificity was 82%. DISCUSSION AND CONCLUSION: Ensuring the head is pitched 30 degrees down and thrust with an unpredictable timing and direction appears to improve sensitivity of the HTT.     

Review article: The medical treatment of Crohn's perianal fistulas

Perianal fistulas are a frequent manifestation of Crohn's disease. The correct application of the newer diagnostic and therapeutic agents for treating perianal Crohn's disease are beginning to be better defined. In general, a combined medical and surgical approach is preferred. The perianal disease process should first be fully delineated with endoscopy and either MRI or EUS before treatment is begun. Patients are then stratified into one of three groups: simple fistulas and no proctitis; simple fistulas and concomitant proctitis; and complex fistulas. Patients with simple fistulas and no proctitis can be treated medically with a combination of antibiotics and an immunosuppressive agent (azathioprine or mercaptopurine). Patients with simple fistulas and concomitant proctitis should have infliximab added to their treatment plan. Complex fistulas require surgical intervention first prior to medical treatment. A combination of antibiotics, immunosuppressive therapy and infliximab are then initiated to facilitate fistula healing.     

Thresholds determined using the monotic and dichotic multiple auditory steady-state response technique in normal-hearing subjects

Auditory steady-state responses (ASSRs) were elicited by presenting single or multiple, 77-105 Hz amplitude-modulated 0.5, 1, 2, and 4 kHz tones to one or both ears. Objectives of this study were to (i) replicate and extend previous multiple ASSR studies in a quiet double-walled sound booth, and (ii) discover differences (if any) between thresholds assessed in monotic and dichotic conditions, which ranged between 15 and 22dB SPL. The present study's behavioural and ASSR thresholds are 0-10 dB lower (better) than results of previous monotic studies. Further, there are no significant differences in ASSR thresholds between dichotic and monotic stimulus conditions. Therefore, dichotic multiple AM tone stimulation does not produce a change in the ASSR that affects threshold estimation in a clinically significant manner. Thus, at least for detecting normal hearing, the dichotic multiple ASSR technique is a feasible method for estimating hearing thresholds that would substantially reduce recording time compared to conventional single-stimulus techniques.     

Role of central preprogramming in dynamic visual acuity with vestibular loss

OBJECTIVE: To determine the contribution of central preprogramming of eye movements to dynamic visual acuity (DVA) during head movement in patients with vestibular hypofunction. STUDY DESIGN: Prospective, clinical study. SETTING: Tertiary care, academic hospitals. PARTICIPANTS: Twenty-six healthy subjects and 20 patients with unilateral (UVL) and 7 with bilateral vestibular loss (BVL) (age range, 20-86 years). INTERVENTIONS: Diagnostic interventions, including caloric and rotational chair testing. MAIN OUTCOME MEASURE: Measurements of DVA during predictable (DVA-predictable) and unpredictable (DVA-unpredictable) head movements using a computerized test. RESULTS: There was a difference between DVA-predictable and DVA-unpredictable scores in all groups (P<.02). The difference between DVA-predictable and DVA-unpredictable scores for the BVL group was significantly greater than that for the other groups (P<.005). Age was a significant factor in DVA-unpredictable scores for the healthy subjects (P<.001) and UVL group (P<.02). Comparisons of DVA between groups were significant (P<.03), with the following exceptions: UVL group for head movements toward the unaffected side for DVA-predictable and DVA-unpredictable scores, compared with healthy subjects, and UVL group for head movements toward the affected side for DVA-predictable scores, compared with the BVL group. CONCLUSIONS: Unpredictable head movements cause a greater decrement in visual acuity than do predictable head movements. This suggests that central programming of eye movements and/or efference copy contributes to gaze stability during predictable head movements in healthy subjects and patients with vestibular hypofunction. Patients with BVL use central programming of eye movements to maintain gaze stability more than do healthy subjects or patients with UVL.     

Valuation of EuroQol Five-Dimensional Questionnaire,Youth Version (EQ-5D-Y) and EuroQol Five-Dimensional Questionnaire,Three-Level Version (EQ-5D-3L) Health States: The Impact of Wording and Perspective

Background

Valuations of health states were affected by the wording of the two instruments (EQ-5D-3L and EQ-5D-Y) and by the perspective taken (child or adult).

Assessing Outcomes in Liver Disease Patients: Reliability and Validity of the Spanish Version of the Liver Disease Quality of Life Questionnaire (LDQOL 1.0)

ObjectiveTo assess the reliability and validity of a Spanish version of the LDQOL 1.0 (Liver Disease Quality of Life questionnaire).MethodsObservational, cross-sectional study in Spanish patients awaiting liver transplantation (LT). Feasibility was assessed by analyzing administration times and missing responses. Ceiling and floor effects were calculated and reliability was tested by examining internal consistency (Cronbach's alpha). Convergent validity was tested by examining correlations between LDQOL disease-specific and Short Form health survey with 36 questions (SF-36) dimensions. Known groups' validity was tested by examining the LDQOL's capacity to discriminate between groups defined by etiology and Child–Turcotte–Pugh (CTP) scores.ResultsA total of 200 patients were included for analysis. Mean age (SD) was 52.6 (9.8) years and 73% of the sample were male. The most common indication for LT was liver cancer (34%). Mean (SD) time to complete the questionnaire was 35.8 minutes (21.2 minutes). Missing responses were highest on the dimensions of sexual functioning and symptoms of liver disease. Ceiling effects were over 20% on 7 of the LDQOL's 12 disease-specific scales. Cronbach's alpha coefficients were over 0.70 on all but 2 dimensions. Correlations between SF-36 and LDQOL disease-specific dimensions generally fulfilled the hypotheses, with 35 of the 40 highest and lowest correlations (87.5%) being in the expected direction. The LDQOL discriminated well between patients in CTP class A and C, and as hypothesized, hepatocarcinoma and alcoholic cirrhosis patients scored better on most dimensions than patients with hepatitis C virus or other etiologies.ConclusionsThe Spanish version of the LDQOL 1.0 has shown satisfactory reliability and validity.     

Using EQ-5D-3L and OAB-5D to assess changes in the health-related quality of life of men with lower urinary tract symptoms associated with benign prostatic hyperplasia

Objectives

To assess changes in the health status of men with lower urinary tract symptoms associated with benign prostatic hyperplasia (LUTS/BPH) using the EQ-5D-3L and OAB-5D instruments and to evaluate the sensitivity of the instruments.

Methods

Data were available from a large randomised phase III trial of men with moderate-to-severe storage and voiding LUTS/BPH (NEPTUNE). Men received a fixed-dose combination of solifenacin 6 mg plus oral controlled absorption system (OCAS?) formulation of tamsulosin (TOCAS, 0.4 mg), TOCAS monotherapy or placebo and completed the EQ-5D-3L and OAB-5D at baseline and weeks 4, 8 and 12. Analysis of covariance was used to estimate changes in EQ-5D-3L Index, EQ-VAS and OAB-5D. Changes in dimension level were summarised using the Paretian Classification of Health Change (PCHC).

Results

Improved health-related quality of life from baseline was seen in all treatment arms on EQ-5D-3L and OAB-5D at week 12, although only OAB-5D showed statistically significant differences between active treatment and placebo, both on the index score and using the PCHC approach. Effect sizes in the active treatment groups were large (>0.8) on OAB-5D but small (≈0.2) on EQ-5D-3L. EQ-5D-3L showed a very high ceiling effect (45% of men reported full health at baseline) and a substantial proportion of these men reported improvements at week 12 in several dimensions of OAB-5D.

Conclusions

A large ceiling effect on EQ-5D-3L substantially limited its sensitivity in this population. OAB-5D proved more sensitive to changes in health status and could be considered a complement to ED-5D-3L as a source of utilities for health economic modelling.