Cost-effectiveness analysis of abrocitinib compared with standard of care in adult moderate-to-severe atopic dermatitis in Japan

Atopic dermatitis (AD) is a chronic inflammatory skin disease with a significant clinical, economic, and human burden. The JAK1 Atopic Dermatitis Efficacy and Safety (JADE) program's Phase 3 trials demonstrated that as a treatment for moderate-to-severe AD in adults with previous exposure to immunotherapy, abrocitinib showed superior efficacy and safety compared with standard of care (SoC), consisting of topical corticosteroids. This study assessed the cost-effectiveness of abrocitinib with SoC versus SoC alone for this patient population in Japan from a societal perspective. A hybrid decision tree and Markov model were used to capture the initial treatment and long-term maintenance phases. Clinical inputs at 16 weeks were obtained through a Bayesian network meta-analysis of four pivotal trials from the JADE program. Clinical inputs at 52 weeks were derived from the JADE EXTEND trial. Response-specific utility inputs were obtained from published literature. Resource use, costs, and productivity inputs were gathered from Japanese claims analysis, literature, public documents, and expert opinion. Costs and quality-adjusted life years (QALYs) were discounted at 2.0% per year and incremental cost-effectiveness ratios (ICERs) were calculated. Sensitivity and scenario analyses were performed to validate the base case results and explore a payer perspective. Over a lifetime horizon and with the base-case societal perspective, abrocitinib produced a mean gain of 0.75 QALYs, incremental costs of JPY (¥) 2 270 386 (USD [$] 17 265.6), and a resulting ICER of ¥3 034 514 ($23 076.5) per QALY compared with SoC. From a payer perspective, the incremental costs increased to ¥4 476 777 ($34 044.4), with an ICER of ¥5 983 495 ($45 502.6) per QALY. The results were most sensitive to treatment-specific, response-based utility weights, drug costs, and productivity-related inputs. From a Japanese societal perspective, abrocitinib demonstrated superior QALYs and with a willingness-to-pay threshold of ¥5 000 000 ($38 023.4) per QALY, can be considered cost-effective compared with SoC as a treatment for moderate-to-severe AD in adult patients with previous immunosuppressant exposure.

A Systematic Literature Review of Economic Evaluations and Cost Studies of the Treatment of Psoriasis, Atopic Dermatitis, and Chronic Urticaria

Introduction

Psoriasis (PSO), atopic dermatitis (AD), and chronic urticaria (CU) are common manifestations of immunological skin and subcutaneous conditions and have been shown to have a substantial impact on the quality of life of patients. The cost of treating those conditions can also be high, as the use of biologic treatments has become more common for moderate to severe patients. In this review, we examine characteristics of economic evaluations and cost studies conducted for the three conditions.

Methods

A literature search was conducted using PubMed, Embase, and the Cochrane Library from January 1, 2016 to October 26, 2020 to identify economic evaluations where the cost of one or more drug treatment was evaluated and cost studies covering any intervention type. Each database was searched using keyword and MeSH terms related to treatment costs (e.g., health care cost, drug cost, etc.) and each condition (e.g., PSO, AD, eczema, CU, etc.).

Results

A total of 123 studies were reviewed, including 104 studies (85%) of PSO (including psoriasis, plaque psoriasis, psoriatic arthritis, and psoriasis vulgaris), 14 studies (11%) of AD, and 5 studies (4%) of CU. Seventy-two studies (59%) reviewed reported the inclusion of biologic treatments, 10 studies (8%) did not include biologic treatments, and 41 studies (33%) did not report whether or not a biologic treatment was included. While nearly all studies (98%) included direct costs, only 22 studies (18%) included indirect costs.

Conclusions

Economic evaluations for AD and CU may be needed in order to better understand the value of new treatments. Moreover, a clearer delineation for biologic treatments and indirect costs (i.e., productivity losses and gains) may be required.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13555-022-00774-2.

Systematic Literature Review of the Use of Productivity Losses/Gains in Cost-Effectiveness Analyses of Immune-Mediated Disorders

INTRODUCTION

In light of the lack of an agreed international standard for how to conduct cost-effectiveness analyses (CEAs), including cost-utility analyses (CUAs) from a societal perspective, there is uncertainty regarding to what extent the inclusion of productivity losses/gains in economic evaluations can affect cost-effectiveness results and subsequently decisions on whether to recommend new health technologies. To investigate this, we conducted a systematic review of CEAs and CUAs of drug-based therapies for a set of chronic immune-mediated disorders to understand how cost elements and calculation methods related to productivity losses/gains are used, examine the impact on the incremental cost-effectiveness ratio (ICER) of including productivity costs, and explore factors that affect the inclusion of productivity loss.

METHODS

Databases (MEDLINE^® In-process, MEDLINE, Embase and Cochrane Library) were searched from January 2010 to October 2020 by two independent reviewers for all CEAs and CUAs in adults with any of the following conditions: ankylosing spondylitis, chronic idiopathic urticaria, Crohn's disease, fibromyalgia, juvenile idiopathic arthritis, psoriasis, rheumatoid arthritis, systemic lupus erythematosus and ulcerative colitis. Relevant study data were extracted and evidence was synthesized for both qualitative and quantitative analysis. Productivity cost elements including absenteeism, presenteeism, unemployment/early retirement, premature mortality and informal care were extracted, along with the method used to determine them. A multivariate analysis was performed to identify factors associated with the inclusion of productivity loss.

RESULTS

Our searches identified 5016 records, culminating in 198 unique studies from 234 publications following screening. Most of the studies investigated rheumatoid arthritis (37.0%) or psoriasis (32.0%). The majority were CUAs, with some including both a CEA and a CUA (73.0%). Most studies used a payer perspective only (28.5%) or a societal perspective only (21.0%). Of the 49 studies incorporating productivity losses/gains, 42 reported the type of cost element used; all of these used patient absenteeism, either alone or in addition with other elements. Only 16 studies reported the method used to value productivity changes, of which eight used a human capital approach, four used a friction cost approach and four used both approaches. Twenty-eight of the 49 studies (57.1%) reported inclusion of productivity losses/gains as contributing to more favourable cost-effectiveness outcomes and ICERs, while 12 (24.5%) reported no substantial impact. On the basis of a multivariate analysis, rheumatoid arthritis as the target disease had a statistically significant association with the inclusion of productivity loss compared with psoriasis and inflammatory bowel disease.

CONCLUSIONS

The results of our review suggest that incorporating productivity cost elements may positively affect cost-effectiveness outcomes in evaluations of therapeutics for immune-mediated disorders. Our work highlights the continued need for clarity when reporting how CEAs and CUAs in this disease area are conducted, in order to better inform healthcare decision-making.

Fuzzy Clustering in Assortative and Disassortative Networks

Despite the significance of assortativity as a property of networks that paves for the emergence of new structural types, surprisingly, there has been little research done on assortativity. Assortative networks are perhaps among the most prominent examples of complex networks believed to be governed by common phenomena, thereby producing structures far from random. Further, certain vertices possess high centrality and can be regarded as significant and influential vertices that can become cluster centers that connect with high membership to many of the surrounding vertices. We propose a fuzzy clustering method to meaningfully characterize assortative, as well as disassortative, networks by adapting the Bonacichi’s power centrality to seek the high degree centrality vertices to become cluster centers. Moreover, we leverage our novel modularity function to determine the optimal number of clusters, as well as the optimal membership among clusters. However, due to the difficulty of finding real-world assortative network datasets that come with ground truths, we evaluated our method using synthetic data but possibly bearing resemblance to real-world network datasets as they were generated by the Lancichinetti–Fortunato–Radicchi benchmark. Our results show our non-hierarchical method outperforms a known hierarchical fuzzy clustering method, and also performs better than a well-known membership-based modularity function. Our method proved to perform beyond satisfactory for both assortative and disassortative networks.

Separated Hierarchical Decomposition of the Choquet Integral

The paper gives a necessary and sufficient condition for a Choquet integral to be decomposable into an equivalent separated hierarchical Choquet-integral system, which is a hierarchical combination of ordinary Choquet integrals with mutually disjoint domains.

Some Characterizations of the Systems Represented by Choquet and Multi-Linear Functionals through the use of Möbius Inversion

The systems represented by the Choquet or the multi-linear fuzzy integral with respect to fuzzy measure is equivalently decomposable into hierarchically sub-systems through the use of Inclusion-Exclusion Covering (IEC) (Theorem 4.1,4.2). Hence, IEC is one of very useful concepts/indexes for structural analysis of the fuzzy integral systems (short for: the systems represented by the Choquet or the multi-linear fuzzy integral) However, it is quite difficult to identify all IEC's. This paper shows a method for identifying it easily, through the use of Möbius inversion (Theorem 5.1).

Canonical Separated Hierarchical Decomposition of the Choquet Integral Over a Finite Set

The paper shows the existence of a canonical separated hierarchical decomposition of the Choquet integral over a finite set. The decomposed system is a hierarchical combination of Choquet integrals with mutually disjoint domains, and equivalent to the original Choquet integral. The paper also gives canonical overlapped hierarchical decompositions of the Choquet integral over a semiatom.

Canonical Hierarchical Decomposition of Choquet Integral Over Finite Set with Respect to Null Additive Fuzzy Measure

In this paper, we provide the necessary and sufficient condition for a Choquet integral model to be decomposable into a canonical hierarchical Choquet integral model constructed by hierarchical combinations of some ordinary Choquet integral models. This condition is characterized by the pre-Znclusion-Exclusion Covering (pre-IEC). Moreover, we show that the pre-IEC is the subdivision of an IEC and that the additive hierarchical structure is the most fundamental one on considering a hierarchical decomposition of the Choquet integral model.

Does migraine-associated vertigo share a common pathophysiology with Meniere's disease? Study with vestibular-evoked myogenic potential

To clarify if migraine-associated vertigo (MAV) and Meniere's disease (MD) share a common pathophysiology, vestibular-evoked myogenic potentials (VEMP) were measured in 11 patients with MAV, 11 with unilateral MD and eight healthy subjects. As acoustic stimuli, tone bursts (TB; 250, 500, 1000 and 2000 Hz) were presented. In healthy subjects, 500-Hz TB evoked the largest amplitude. To quantify this tendency, 500-1000 VEMP slope was calculated, and 500-1000 VEMP slope was the smallest on the affected side of MD patients. Among the 11 MD patients, five had significantly decreased 500-1000 VEMP asymmetry (shift of the tuning to 1000 Hz). Three of the 11 MAV patients also showed a significantly decreased 500-1000 VEMP slope. This finding suggests that MAV might share a common pathophysiology with MD. In addition to this finding, four of the other eight MAV patients showed prolonged p13 latencies. This suggests that MAV could consist of patients with different lesion sites.

Some Characterizations of k-Monotonicity Through the Bipolar Möbius Transform in Bi-Capacities

This paper first proposes the bipolar Möbius transform as an extension of dividends of cooperative games to that of bi-cooperative games (bi-capacities) defined on 3N, which is different from the Möbius transform defined by Grabisch and Labreuche. The k-monotonicity of bi-capacities is characterized through each of the following notions: the bipolar and ordinary Möbius transforms, discrete derivatives, and partial derivatives of the piecewise multilinear extension of the ternary pseudo-Boolean function corresponding to the bi-capacities.

“Heart and Mind” Evaluation

Special Interest Group in Evaluation (SIG Eval) of Japan Society for Fuzzy Theory and intelligent informatics was founded by Professor Hisao Shiizuka, Kogakuin University, in 1993 to facilitate the exchange of research information within Japan on evaluation problems. Since 1996, SIG Eval has held an annual workshop, the Workshop on Evaluation of Heart and Mind. In addition to the workshop, SIG Eval has edited this special issue on “Heart and Mind” Evaluation. Contributors include those who often speak at the workshop. The first article, “Feasibility Study on Marketing Research Using Eye Movement: An Investigation of Image Presentation using an Eye Camera and Data Processing,” by Shin'ya Nagasawa, Sora Yim, and Hitoshi Hongo, asserts that, in physiological experiments using an eye camera, the user's interest influences purchasing behavior. The second article, “Statistical Image Analysis of Psychological Projective Drawings,” by Kazuhisa Takemura, Iyuki Takasaki, and Yumi Iwamitsu, discusses the use of statistical image analysis to overcome the difficulty in assessing the reliability of projective drawing techniques. The third article, “Fuzzy Least Squares Regression Analysis for Social Judgment Study,” by Kazuhisa Takemura, proposes fuzzy regression analysis in which a dependent variable, independent variables, and regression parameters are represented by triangular fuzzy numbers. The fourth to sixth articles discuss fuzzy measures, or capacities, which are quite popular for their application in subjective evaluation. The fourth article, “Identification of Fuzzy Measures with Distorted Probability Measures,” by Aoi Honda and Yoshiaki Okazaki, classifies fuzzy measures by introducing the concept of order type, and proposes the method of identifying fuzzy measure μ as a distorted probability of the same, or similar, order type as μ The fifth article, “Semiatoms in Choquet Integral Models of Multiattribute Decision Making,” by Toshiaki Murofushi, characterizes the concept of the semiatom in fuzzy measure theory in the multiattribute preference relation represented by a Choquet integral. The last article, “Some Characterizations of k-Monotonicity through the Bipolar Möbius Transform in Bi-Capacities,” by Katsushige Fujimoto and Toshiaki Murofushi, proposes the bipolar Möbius transform as an extension of the conventional Möbius transform of capacities to that of bi-capacities; the concept of bi-capacity was proposed by Grabisch and Labreuche (2002) for modeling decision making on a bipolar scale. We thank the reviewers and contributers for their time and effort in making this special issue possible, and we wish to thank the JACIII editorial board, especially Professors Kaoru Hirota and Toshio Fukuda, the Editors-in-Chief, and Kenta Uchino, Managing Editor, for their support and advice in putting this special issue together. I have assumed the role of General Chair of the Joint Conference of the Third International Conference on Soft Computing and Intelligent Systems and the Seventh International Symposium on Advanced Intelligent Systems (SCIS & ISIS 2006), to be held at Tokyo Institute of Technology, Japan, on September 20--24, 2006. As is customary, selected papers will be published in special issues of this journal. We invite you to submit your research papers and to participate in SCIS & ISIS 2006. For further information, please visit <u>http://scis2006.cs.dm.u-tokai.ac.jp/</u>.

Semiatoms in Choquet Integral Models of Multiattribute Decision Making

The semiatom is characterized in terms of the multiattribute preference relation represented by a Choquet integral. It is concluded from the characterization that the proper semiatom, the semiatom which is not an atom, is pathological in multiattribute decision making.

Myelin-deficiency in the cochlear nerve of the 'bt' mutant hamster

In a previous report, we showed abnormal auditory evoked potentials in the mutant hamster, 'black tremor (bt)', with significantly prolonged wave latencies of auditory brainstem responses and prolonged N1 latencies of compound action potentials, but normal cochlear microphonics. In this report, we present the results of morphological studies supporting the results of our electrophysiological studies of the auditory pathway in bt. Observation by transmission electron microscopy revealed an abnormal myelin sheath surrounding the spiral ganglion cells, and a thinner compact myelin sheath surrounding the axons in bt than in normal hamsters. The bt hamster has a myelin deficiency not only in the brainstem, but also in the cochlear nerve.

Click- and short tone burst-evoked myogenic potentials in cerebellopontine angle tumors

We report results of vestibular-evoked myogenic potentials (VEMPs) in patients with cerebellopontine angle tumors and compare results obtained using clicks with those obtained using 500 Hz short tone bursts (STB). We reviewed the records of 87 patients with cerebellopontine angle tumors. Clicks (0.1 ms, 95 dB nHL) were presented to all patients and STB (500 Hz, rise/fall time 1 ms, plateau time 2 ms, 95 dB nHL) were presented to 27 patients. Click-evoked VEMPs were abnormal in 69/87 patients (79%; no response in 55 patients, decreased response in 14 patients, normal response in 18 patients). STB-evoked VEMPs were abnormal in 22/27 patients (82%; no response in 18 patients, decreased response in 4 patients, normal response in 5 patients). Click- and STB-evoked VEMPs were identical in 23/27 patients (85%). Two patients showed normal STB-evoked VEMPs and decreased click- evoked VEMPs, and 2 patients showed decreased STB-evoked VEMPs and absent click- evoked VEMPs. These results confirm our previous study in a small number of patients. Vestibular afferents seem to respond better to 500 Hz STBs than to clicks.

The outcome of the canalith repositioning procedure for benign paroxysmal positional vertigo: are there any characteristic features of treatment failure cases?

To demonstrate the success rate of the canalith repositioning procedure (CRP) in our clinic and to establish any characteristic features of cases of treatment failure, we reviewed clinical records of 62 patients who were diagnosed with posterior semicircular canal-benign paroxysmal positional vertigo (BPPV) and treated with the CRP. The basic strategy of the CRP was to rotate the involved canal slowly in the plane of gravity so that free-floating materials could migrate into the utricle only once. After the procedure we instructed patients to keep their heads upright for 10 h and not to sleep on the affected ear for 2 weeks. After the initial treatment, successful results were obtained in 51 of the 62 patients (82.2%). After the second treatment, 56 patients (90.3%) experienced success. Six patients (9.7%) did not obtain resolution even after the second treatment. While 46 patients were diagnosed with idiopathic BPPV, in 16 patients a different diagnosis was determined (head injury in 7 patients, Ménière's disease in 2, vestibular neuritis in 2 and unilateral sensorineural hearing loss in 5). We categorized these 16 patients as having secondary BPPV. Patients with idiopathic BPPV showed a significantly higher success rate with CRP than those with secondary BPPV. Patients with secondary BPPV may have quantitatively or qualitatively different lesions than those with idiopathic BPPV.

The effects of plateau time on vestibular-evoked myogenic potentials triggered by tone bursts

Vestibular-evoked myogenic potentials (VEMPs) can be triggered by acoustic, vibratory or galvanic stimuli. However, each method has drawbacks for studying if the vestibulocollic reflex is intact in the patients tested. We used air-conducted VEMPs as a screening test to examine the integrity of the sacculocollic reflex. In a previous study, we defined the optimal rise/fall time of short tone bursts (STBs) to evoke VEMPs. In this paper, we studied the optimal plateau time of tone bursts to evoke VEMPs. Four different plateau times (1, 2, 5 and 10 ms) were used in a random order to test 26 normal ears. VEMP responses (p13/n23) triggered by the tone bursts were clearly observed in all ears. When the plateau time was increased in order from 1 to 10 ms, the latencies (p13, n23) and interval (p13-n23) were also increased in parallel, although significant differences were not observed between some plateau times. Considering the latencies and interval together for the four plateau times, the variances were smallest for the 2 ms plateau time, meaning that it caused the smallest interaural VEMP differences. The amplitude or relative amplitude in individual ears was lowest for the 1 ms plateau time, while it was comparable for the other three plateau times. In conclusion, we recommend that the ideal stimulation pattern for evoking STB VEMPs is as follows: frequency 500 Hz; stimulation repetition rate 5 Hz; rise, fall time 1 ms; and plateau time 2 ms. The waveform morphology of the VEMP responses observed with this stimulation pattern was simultaneously the most constant and marked.

Vestibular evoked myogenic potentials in patients with idiopathic bilateral vestibulopathy. Report of three cases

Idiopathic bilateral vestibulopathy (IBV) is an acquired bilateral peripheral vestibular disorder of unknown cause. Three patients diagnosed as IBV by neuro-otological examination were reported. They underwent vestibular evoked myogenic potential (VEMP) testing which reflects the functionality of the sacculo-collic pathway. As a result, 2 of the 3 patients showed bilateral absence of VEMPs and one showed unilateral absence. The VEMPs of the 3 patients revealed that IBV affects not only the superior but also the inferior vestibular nerve systems. As previously reported in the cases of vestibular neuritis, VEMP could be useful for classifying IBV according to the function of the inferior vestibular nerve.

The effect of rise/fall time on vestibular-evoked myogenic potential triggered by short tone bursts

Vestibular-evoked myogenic potentials (VEMPs) are used more and more frequently as a clinical tool to test if the sacculocollic reflexes are intact in patients. They can be evoked by short tone bursts (STBs) as well as by clicks. Although most previous studies used traditional clicks to generate VEMP responses, our clinical experience showed that STBs were prone to evoke them more clearly, at least in some patients. Four kinds of STB stimulation patterns in a random order were used to test 22 ears using changing rise/fall times (0.3, 1, 3 and 10 ms). VEMP responses (p13/n23) triggered by these patterns were clearly observed in all 22 ears. When the rise/fall time was prolonged from 0.3 to 10 ms, the p13 latency was prolonged in parallel. There was a similar trend for the n23 latency, although a significant difference was not attained between 0.3 ms and 1 ms rise/fall times. Considering the p13 and n23 latencies for the 4 rise/fall times, the variances were smallest for the 1 ms stimulation, meaning that it caused the smallest interaural latency differences. The amplitude or relative amplitude in the individual ears tested was lowest for the 10 ms stimulation, being comparable among the other 3 rise/fall times. In conclusion, the 1 ms rise/fall time was a remarkable stimulation pattern because its VEMP responses were simultaneously more constant and conspicuous.

Diagnostic value of prolonged latencies in the vestibular evoked myogenic potential

BACKGROUND

As a parameter for the evaluation of the vestibular evoked myogenic potential (VEMP), amplitude has been used clinically. However, the significance of latency has not been considered.

OBJECTIVE

To clarify the diagnostic value of latencies of the VEMP.

DESIGN

We reviewed records of the VEMP of patients with various diseases and compared them with records of healthy volunteers.

SETTING

Data were collected from patients in an outpatient clinic of a tertiary care center and healthy volunteers.

SUBJECTS

Clinical records of 134 patients (61 men and 73 women, aged 20-75 years) were reviewed. Diagnoses were Meniere disease in 43 patients, acoustic neuroma in 62 patients, vestibular neuritis in 23 patients, and multiple sclerosis in 6 patients. Also, 18 healthy volunteers (13 men and 5 women, aged 25-38 years) were enrolled.

INTERVENTION

Diagnostic.

MAIN OUTCOME MEASURES

Click-evoked myogenic potentials were recorded with surface electrodes over each sternocleidomastoid muscle. Latencies and amplitudes of responses were measured.

RESULTS

Vestibular evoked myogenic potentials were absent or decreased in 51% of patients with Meniere disease (n = 22), 39% with vestibular neuritis (n = 9), 77% with acoustic neuroma (n = 48), and 25% with multiple sclerosis (3 of 12 sides of 6 patients). Concerning latency, patients with Meniere disease or vestibular neuritis hardly showed any latency prolongation. Four patients with acoustic neuroma showed prolonged p13; all had large tumors. All patients with multiple sclerosis showed prolonged p13.

CONCLUSION

Prolonged latencies of the VEMP suggest lesions in the retrolabyrinthine, especially in the vestibulospinal tract.

Glycerol affects vestibular evoked myogenic potentials in Meniere's disease

OBJECTIVES

to show that abnormal vestibular evoked myogenic potentials on the sternocleidomastoid muscle (SCM) in patients with unilateral Meniere's disease are caused by endolymphatic hydrops.

SUBJECTS

six normal volunteers and 17 patients with unilateral Meniere's disease were examined.

METHODS

click-evoked myogenic potentials were recorded with surface electrodes over each SCM. Responses evoked by clicks recorded after oral administration of glycerol (1.3 g/kg body weight) were compared with those recorded before administration.

RESULTS

the change rate of the p13-n23 amplitude was calculated. The mean+standard deviation (S.D.) of the change rate was 3.52+14.6% in normal subjects. On the unaffected side of patients the change rates were within the normal range (within the mean+/-2S.D.) in 13 patients, and three ears showed significant decrease. Only one ear showed significant increase. On the affected side, five ears showed significant increase of the amplitude while two ears showed significant decrease after oral administration of glycerol. Effects on evoked myogenic potentials were independent of those on pure tone hearing.

CONCLUSION

vestibular evoked myogenic potentials in some patients with unilateral Meniere's disease were improved by oral administration of glycerol. This result suggests that abnormal vestibular evoked myogenic potentials in patients with unilateral Meniere's disease could result from endolymphatic hydrops.

Sensorineural hearing loss as the initial manifestation of polyarteritis nodosa

A 74-year-old male was referred for the sudden onset of bilateral sudden deafness. The patient had no history of any disease or trauma to the head. Pure tone audiometry revealed bilateral moderate, to severe, sensorineural hearing loss. Auditory brain stem responses (ABRs) showed normal peak and interpeak latencies. These audiological findings suggested that his hearing loss could be attributed to inner ear lesions. However, we felt an alternative explanation for this sudden deafness was likely to exist because the patient also had a month-long fever of unknown origin (FUO) and weight loss of 5 kg/month. Using the criteria of The American College of Rheumatology, we made the diagnosis of polyarteritis nodosa (PAN). Serum MPO-ANCA was positive (x 661). For treatment, the patient was begun on prednisolone and cyclophosphamide. Nine months later, fever, hypertension, nephritis, pneumonitis, and arthritis had completely resolved, the MPO-ANCA became negative (MPO-ANCA < x 10). Furthermore, his hearing improved.

Narrow internal auditory meatus: an idiopathic case confirming the origin and pathway of vestibular evoked myogenic potentials in humans

OBJECTIVE

To confirm the origin and pathway of vestibular evoked myogenic potentials (VEMPs) in humans.

DESIGN

Case study.

SETTING

University hospital.

PATIENT

A patient with a narrow internal auditory meatus (IAM).

MAIN OUTCOME MEASURES

Imaging studies and functional studies concerning the seventh and eighth cranial nerves.

RESULTS

Of the 4 nerves in the IAM, all but the cochlear nerve had normal function and normal courses, despite the pronounced narrowing of the IAM. The facial nerve had a normal diameter, but the vestibular nerves were thinner. Imaging revealed that the cochlear nerve was absent or extremely thinned. Both the cochlea and the cochlear nerve showed no function in the affected ear, although the VEMPs were evoked normally.

CONCLUSION

Our results definitively support the vestibular origin of VEMPs in humans.

The effect of sternocleidomastoid electrode location on vestibular evoked myogenic potential

OBJECTIVE

The purpose of this study was to investigate the effect of a sternocleidomastoid (SCM) electrode array on the vestibular evoked myogenic potential (VEMP) and the most optimal recording site for clinical use.

METHODS

Fifteen normal adults (10 men and 5 women, aged 18 to 38 years) were tested. We placed electrodes at four different locations over the SCM muscle: the upper part of the SCM muscle at the level of mandibular angle, the middle part of the muscle, and immediately above sternal and clavicular origins of the SCM muscle. Sound evoked myogenic potentials in response to monoaurally delivered short tone-bursts (500 Hz at 95 dBnHL, rise/fall time=1 ms and plateau=2 ms) were recorded with surface electrodes over the isometrically contracting SCM muscle.

RESULTS

On the clavicle, the upper and middle parts of SCM from all subjects, air-conducted short tone burst evoked biphasic responses (p13-n23). VEMPs recorded at the upper part of the muscle showed the largest amplitude, followed by that at the middle part. However, the latency of the first peaks (p13-n23) was not constant in the upper part. Recording from the middle part of SCM muscle were more consistent.

CONCLUSION

Our findings suggest that the middle part of the SCM muscle is the optimal location for recording vestibular evoked myogenic potential.

Vestibular function in auditory neuropathy

Auditory neuropathy is characterized by mild-to-moderate pure-tone hearing loss, poor speech discrimination out of proportion with this loss, absent or abnormal auditory brainstem responses and normal outer hair cell function as measured by otoacoustic emissions and cochlear microphonics. We followed three patients in our clinic whom we classified as auditory neuropathy patients. These patients also complained of balance disorders and we report our auditory and vestibular system analyses of these patients. The data presented herein include results of audiometric tests (serial pure-tone audiometry and speech discrimination tests), otoacoustic emissions, auditory-evoked brainstem responses and vestibular function tests (clinical tests of balance, electronystagmography, damped rotation tests and vestibular-evoked myogenic potentials). In all patients, pure-tone audiometry revealed mild-to-moderate sensorineural hearing loss, markedly poor speech discrimination scores and absent auditory-evoked brainstem responses, all in the presence of normal otoacoustic emissions. Balance tests (caloric tests and damped rotation test) were abnormal. Saccades, smooth pursuit eye movements and optokinetic nystagmus were normal in all patients. Neurological and motor system evaluations were normal in all patients. These three auditory neuropathy patients manifest a disorder of cochlear nerve function in the presence of normal outer hair cell activity. They additionally manifest a disorder of the vestibular nerve and its end organs. We conclude that, in patients with isolated auditory neuropathy, the vestibular branch of the VIIIth cranial nerve and its innervated structures may also be affected. We suggest the use of the term "cochlear neuropathy" to characterize those patients with involvement of only the auditory branch of the VIIIth cranial nerve and its innervation.

Vestibular evoked myogenic potentials in patients with spinocerebellar degeneration

To estimate vestibulo-collic reflexes in patients with spinocerebellar degeneration (SCD), vestibular evoked myogenic potentials (VEMPs) were recorded in 16 patients with SCD and in 9 normal subjects. The patients with SCD were classified into three groups: those with olivo-ponto-cerebellar ataxia (OPCA; n = 10); those with cortical cerebellar atrophy (CCA; n = 3); and those with Machado-Joseph disease (MJD; n = 3). While all of the patients with OPCA and CCA showed biphasic responses (p13-n23), 2 of the 3 patients with MJD showed abnormal VEMPs bilaterally. Three sides in these 2 patients showed an absence of VEMPs, and one side showed a remarkably delayed p13. These two patients showed little response in caloric tests. These results suggest that the vestibulo-collic reflex as well as the vestibulo-ocular reflex could be damaged in MJD patients but preserved in OPCA and CCA patients.

Bone-conducted evoked myogenic potentials from the sternocleidomastoid muscle

The aim of this study was to show that bone-conducted clicks and short tone bursts (STBs) can evoke myogenic potentials from the sternocleidomastoid muscle (SCM) and that these responses are of vestibular origin. Evoked potential responses to bone-conducted auditory stimuli were recorded from the SCMs of 20 normal volunteers and from 12 patients with well-defined lesions of the middle or inner ear or the VIIIth cranial nerve. The subjects, who had various labyrinthine and retro-labyrinthine pathologies, included five patients with bilateral profound conductive hearing loss, two with bilateral acoustic neuroma post-total neurectomy and five with bilateral sensorineural hearing loss. Air- and bone-conducted evoked myogenic potentials in response to clicks and STBs were recorded with surface electrodes over each SCM of each subject. In normal subjects, bone- and air-conducted clicks and STBs evoked biphasic responses from the SCM ipsilateral to the stimulated ear. The bone-conducted clicks evoked short-latency vestibular-evoked myogenic potential (VEMP) responses only in young subjects or in subjects with conductive hearing loss. STBs evoked VEMPs with higher amplitude and better waveform morphology than clicks with the same acoustic intensity. Patients with total VIIIth cranial nerve neurectomy showed no responses to air- or bone-conducted click or STB stimuli. Clear VEMP responses were evoked from patients with conductive or sensorineural hearing loss. It is concluded that loud auditory stimuli delivered by bone- as well as air conduction can evoke myogenic potentials from the SCM. These responses seem to be of vestibular origin.

Isolated directional preponderance of caloric nystagmus: I. Clinical significance

OBJECTIVES

To determine the clinical significance of an isolated directional preponderance (DP) on bithermal caloric testing. An isolated caloric DP was defined as a DP, calculated according to the standard Jongkees formula, of > or = 40%, with a spontaneous nystagmus (SN) in darkness of < or = 2 degrees/s and a canal paresis (unilateral weakness) of < or = 25%.

STUDY DESIGN

A retrospective analysis of all 15,542 bithermal caloric tests performed in the authors' department in the previous 10 years to identify all tests with an isolated DP of > or = 40%. This was followed by a review of the clinical data on the 144 patients identified with such a result and then by a telephone or postal follow-up study of these patients. The study group eventually comprised 114 patients; these were patients in whom a clinical diagnosis could be made at the time the caloric test was done, or who responded to requests for follow-up information. The 34 patients in whom a clinical diagnosis could not be made at the time of the caloric test, and who did not respond to requests for follow-up information, were excluded.

STUDY SETTING

A balance disorders clinic in a tertiary referral hospital.

INTERVENTION

All patients underwent standard bithermal caloric testing. Some of the patients also underwent rotational testing.

OUTCOME MEASURES

A clinical diagnosis for the cause of the isolated DP, made either at the time of the caloric test or on the basis of information supplied at follow-up by the patient or by the referring physician.

RESULTS

Of 114 patients, 39 had benign paroxysmal positioning vertigo, 14 had Ménière's disease, and 5 had migrainous vertigo. Five patients had central nervous system (CNS) disorders, and this was clinically apparent at the time of the caloric test in 4, so that only 1 patient with an isolated DP developed evidence of a CNS disorder after the caloric test was done. In the other 54 patients, no definite diagnosis could be made, but 41 of these 54 were either completely well or much better at follow-up.

CONCLUSIONS

An isolated DP on caloric testing is usually a transient, benign disorder. About half the patients with an isolated DP have either Ménière's disease or benign paroxysmal positioning vertigo; in most of the other half, no definite diagnosis is made but most of these patients will do well. Only approximately 5% have a CNS lesion and in almost all this is apparent at the time the caloric test is done. In a relapsing-remitting peripheral vestibular disorder such as benign paroxysmal positioning vertigo or Ménière's disease, the mechanism of an isolated DP could be enhanced dynamic gain of ipsilesional medial vestibular nucleus neurons, perhaps as a result of intermittent hyperfunction of primary semicircular canal vestibular afferents. The authors postulate that an isolated DP reflects a gain asymmetry between neurons in the medial vestibular nucleus on either side, caused either by increased sensitivity on one side or by reduced sensitivity on the other, perhaps as an adaptive change in response to abnormal input. In an accompanying article, the authors implement a realistic neural network model in which it is possible to simulate an isolated DP by adjusting the dynamic sensitivity of type 1 medial vestibular nucleus neurons on one side or of type 2 medial vestibular nucleus neurons on the other.

Tone burst-evoked myogenic potentials in human neck flexor and extensor

Vestibular evoked myogenic potential (VEMP) has been proposed to be a manifestation of sacculocollic reflex. In a recent study using intracellular recording from neck flexor and extensor motoneurons, the neuronal connections and pathways underlying sacculocollic reflexes were determined in cats. The results showed that sacculocollic reflex displayed inhibitory connection to bilateral neck flexors and excitatory connection to bilateral neck extensors. A total of 16 normal young adults were tested with bilateral recordings of sternocleidomastoid (SCM) and splenius capitis (SC) muscles by acoustic stimulus of 500 Hz short tone burst. The results revealed that polarity of the wave I/II of VEMP on SC was the reverse of that on SCM. This implied that VEMP from ipsilateral SCM showed inhibitory neural activity; whereas VEMP from ipsilateral SC was an excitatory response. Using this non-invasive technique, the sacculocollic reflexes in human neck flexor and extensor were studied. The results in humans were consistent with the previous findings in cats.

Periodic alternating nystagmus and congenital nystagmus: similarities in possibly inherited cases

In this paper, 2 patients, a daughter with periodic alternating nystagmus and a mother with congenital fixation nystagmus, are presented, and the similarities of the two disorders are discussed, not only in the eye movements, but also in their underlying abnormalities. The literature was reviewed, and the link between periodic alternating and congenital fixation nystagmus, which had been suggested based on circumstantial evidence, may be confirmed by our cases. The possible evidence of inheritance suggests that the two disorders share common abnormalities in visual processing.

Auditory brainstem responses, electrocochleograms, and cochlear microphonics in the myelin deficient mutant hamster 'bt'

Electrophysiological studies of the auditory pathway were performed on the mutant hamster 'bt' which is known to have myelin deficiencies in the central nervous system. Auditory brainstem responses (ABRs), electrocochleograms (EcochGs), and cochlear microphonics (CMs) were recorded. ABRs in 'bt' demonstrated markedly transformed waveforms with significantly prolonged latencies. EcochG in 'bt' showed significantly prolonged N1 latencies of the compound action potentials (CAPs) while 'bt' showed normal CMs. The myelin deficient mutant hamster 'bt' may have myelin deficiencies not only in the brainstem auditory pathway but also in the cochlear nerve.

Short tone burst-evoked myogenic potentials on the sternocleidomastoid muscle: are these potentials also of vestibular origin?

OBJECTIVES

To show that short tone bursts (STBs) evoke myogenic potentials from the sternocleidomastoid muscle (SCM) that are of vestibular origin.

DESIGN

Evoked potential activity was recorded from the SCMs of normal volunteers and from patients with vestibulocochlear disorders.

SETTING

This outpatient study was conducted at the Department of Otolaryngology, University of Tokyo, Tokyo, Japan.

SUBJECTS

Nine normal volunteers and 30 patients (34 affected ears) with vestibulocochlear disorders were examined.

INTERVENTION

Diagnostic.

OUTCOME MEASURES

Sound-evoked myogenic potentials in response to STBs were recorded with surface electrodes over each SCM. Responses evoked by STBs in patients were compared with responses evoked by clicks.

RESULTS

In all normal subjects, STBs (0.5, 1, and 2 kHz) evoked biphasic responses on the SCM ipsilateral to the stimulated ear; the same was true for clicks. Short tone bursts of 0.5 kHz evoked the largest responses, while STBs of 2 kHz evoked the smallest. In patients with vestibulocochlear disorders, responses to STBs of 0.5 kHz were similar to responses evoked by clicks. Thirty (88%) of the 34 affected ears demonstrated the same results with 0.5-kHz STBs and with clicks. Responses were present in patients with total or near-total hearing loss and intact vestibular function. Conversely, patients with preserved hearing but with absent or severely decreased vestibular function had absent or significantly decreased myogenic potentials evoked by STBs.

CONCLUSIONS

Short tone bursts as well as clicks can evoke myogenic potentials from the SCM. Myogenic potentials evoked by STBs are also probably of vestibular origin.

Vestibular evoked myogenic potentials in acoustic tumor patients with normal auditory brainstem responses

In order to clarify the utility of the vestibular evoked myogenic potential (VEMP) in detecting acoustic tumors, we report two patients who were found to have normal auditory brainstem responses (ABRs) and abnormal VEMPs. To record VEMPs, electromyographic responses to brief loud clicks (0.1 ms at 95 dBnHL) were amplified and averaged on the sternocleidomastoid muscle ipsilateral to the stimulated side. The stimulation rate was 5 Hz and the analysis time 50 ms. The first case was a 54-year-old woman in whom VEMPs were absent on the affected side while caloric tests and ABRs were normal. The second case was a 58-year-old woman whose VEMPs were absent on the affected side while caloric tests revealed a 22% canal paresis and normal ABRs. These results and previous studies suggested that the VEMP could reflect a function different from those evaluated by the ABR or the caloric test. We concluded that the VEMP can provide useful information in diagnosing acoustic tumors.

Vestibular evoked myogenic potentials in patients with bilateral profound hearing loss

We report vestibular evoked myogenic potentials (VEMPs) in 3 patients with bilateral profound hearing loss in order to confirm that they are not of cochlear origin. All of the 3 patients (31-year-old man, 67-year-old man and 47-year-old woman) had bilateral profound hearing loss. They were diagnosed as having congenital hearing loss, bilateral Ménière's disease and inner ear syphilis. Their pure-tone hearing ranged from 81 dB HL to nearly total hearing loss. Stimulation by click (95 dB nHL) evoked biphasic myogenic responses (p13-n23) on the sternocleidomastoid muscle ipsilateral to the stimulated ear. The ear in which the stimulation did not evoke biphasic myogenic responses did not have a caloric response either. These results suggested that VEMPs are not likely of cochlear origin but of vestibular origin.

The effect of click repetition rate on vestibular evoked myogenic potential

Vestibular evoked myogenic potentials (VEMPs) generated by click stimulation and recorded on the sternocleidomastoid muscle have been used as a test of vestibular reflexes. Various parameters of the stimulus and recording setting have been studied. However, the influence of stimulation repetition rate of VEMPs and the most optimal stimulation rate for clinical use have not yet been defined. Each ear of 12 normal adults was tested at five different click stimulation rates (1 Hz, 5 Hz, 10 Hz, 15 Hz and 20 Hz) in random order. VEMP responses were evident in all 24 ears stimulated with 1 Hz, 5 Hz and 10 Hz. One ear was void of response at 15 Hz stimulation and nine ears at 20 Hz stimulation. The relative amplitude or the rank of amplitude in individual ears was higher at 1 Hz and 5 Hz stimulation, progressively decreasing as the stimulation rate increased. Comparisons of p13 and n23 latencies showed no difference among five stimulation rates, but variance was greatest at 20 Hz stimulation and smallest at 1 Hz. VEMPs generated at lower stimulation repetition rate seemed to be more marked and constant. However, with regard to examination time and patient compliance, a 5 Hz stimulus is advisable if both short examination time and higher signal/noise ratio are required.

Vestibular evoked myogenic potentials in patients with acoustic neuromas

BACKGROUND

To diagnose acoustic neuromas (ANs), the auditory brainstem response test and the caloric test have been used in addition to magnetic resonance imaging. The auditory brainstem response and the caloric tests mainly reflect functions of the auditory pathway, ie, the cochlear nerve and the superior vestibular nerve, respectively. Because the vestibular evoked myogenic potential (VEMP) has been thought to originate in the inferior vestibular nerve, we hypothesized that the VEMP could provide different information from the auditory brainstem response and the caloric test and that it could be helpful in diagnosing ANs. In other words, we hypothesized that the VEMP could provide information concerning inferior vestibular nerve involvement in patients with ANs.

OBJECTIVE

To find out if the VEMP could be useful in classifying ANs according to the involved nerves.

DESIGN

We reviewed preoperative clinical tests, including VEMPs, in 21 patients (8 men, 13 women) with ANs confirmed surgically and histopathologically, comparing them with VEMPs in 8 normal subjects (5 men, 3 women).

RESULTS

Whereas the first positive-negative peak of the VEMP, P13-N23, was ipsilaterally present on stimulation of the unaffected side in all patients with ANs and both sides in all normal subjects, it was absent on the affected side in 15 patients (71%) and significantly decreased in amplitude in 2 patients (9%). Thus, 17 (80%) of the 21 patients showed abnormal VEMPs. Three patients had abnormal VEMPs although they had normal caloric responses. Three patients had abnormal caloric responses although they had normal VEMPs.

CONCLUSION

These results suggest that the VEMP could be useful for the diagnosis of AN, especially for classifying ANs according to the involved nerves.

Bilateral pseudo-internuclear ophthalmoplegia in myasthenia gravis

A 38-year-old male with bilateral pseudo-internuclear ophthalmoplegia (-INO) in myasthenia that could have been misdiagnosed as INO in multiple sclerosis is reported. He experienced fluctuating symptoms including double vision, imbalance, and tinnitus. His eye movements simulated bilateral INO, with a downshoot in abduction. After thymectomy, his eye movements became normal. From our case and a review of the literature, we propose that ptosis, downshoot, and fatigability are likely to be signs of pseudo-INO in myasthenia, whereas an impaired vertical smooth pursuit is unlikely. Dissociated nystagmus and monocular overshoot might be the results of central compensation.

Perineural Spread of Facial Squamous Cell Carcinoma to the Vestibulocochlear Nerve

Perineural spread of facial squamous cell carcinoma (SCC) is a well-recognized cause of trigeminal and of facial nerve palsies. 1 Vestibulocochlear nerve involvement by perineural spread has not been convincingly demonstrated. Here we report a patient with perineural spread of facial SCC not only to the trigeminal and facial nerves but also to the ipsilateral vestibulocochlear nerve. The anatomic and pathophysiologic basis of this spread is discussed.