Recovery of positional nystagmus after benign paroxysmal positional vertigo fatigue.

PURPOSE: In benign paroxysmal positional vertigo (BPPV), positional nystagmus is generally weaker when the Dix-Hallpike test is repeated. This phenomenon is known as BPPV fatigue. The positional nystagmus induced by the Dix-Hallpike test can be observed again when time has passed. There has been no study regarding the length of time required to recover the positional nystagmus. The purpose of this study was to examine whether positional nystagmus recovers within 30 min after the disappearance of the nystagmus by BPPV fatigue. METHODS: This was a prospective observational study. Twenty patients with posterior canal type of BPPV (canalolithiasis of the posterior canal) were included. Dix-Hallpike tests were performed three times for each patient. A second Dix-Hallpike test was performed immediately after the first Dix-Hallpike test. A third Dix-Hallpike test was performed 30 min after the second Dix-Hallpike test. We recorded positional nystagmus induced by the Dix-Hallpike tests and analyzed maximum slow-phase eye velocity (SPEV) of the positional nystagmus. RESULTS: The average maximum SPEV of positional nystagmus induced by the second Dix-Hallpike test (4.8°/s) was statistically lower than that induced by the first Dix-Hallpike test (48.0°/s); this decrease was caused by BPPV fatigue. There was no statistical difference between average maximum SPEV of positional nystagmus induced by the first Dix-Hallpike test and that induced by the third Dix-Hallpike test (41.6°/s); this indicates that the effect of BPPV fatigue disappeared. The effect of BPPV fatigue disappears within 30 min. CONCLUSIONS: A second Dix-Hallpike test should be performed at least 30 min after the first.

Assessment of endolymphatic hydrops and otolith function in patients with Ménière's disease.

Ménière's disease is associated with hydrops of the inner ear endolymphatic space, and histopathologically, the cochlea and vestibule are usually involved. We used gadolinium-enhanced magnetic resonance imaging and measured cervical and ocular vestibular evoked myogenic potentials and the gain in the utricular induced linear vestibulo-ocular reflex to test the hypothesis that vestibular hydrops in Ménière's disease patients is associated with otolith organ dysfunction. We evaluated 21 patients diagnosed with unilateral definitive Ménière's disease using gadolinium magnetic resonance imaging to detect endolymphatic hydrops in the cochlea and vestibule. Cervical and ocular vestibular evoked myogenic potentials and the gain in utricular induced linear vestibulo-ocular reflex during eccentric rotation were measured to assess otolith organ function. For eccentric rotation, patients were rotated while displaced from the axis of rotation, while linear acceleration stimulated the utricle and induced the vestibulo-ocular reflex. Magnetic resonance imaging revealed vestibular hydrops in 14 of 20 patients (70%). Among the 14 patients, ten (71%) had abnormal cervical and three (21%) had abnormal ocular vestibular evoked myogenic potentials. Four patients (4/21, 19%) had abnormal linear vestibulo-ocular reflexes, three of whom also had abnormal ocular vestibular evoked myogenic potentials. Overall, 16 of 17 patients had normal linear vestibulo-ocular reflexes and normal ocular vestibular evoked myogenic potentials. Vestibular endolymphatic hydrops in Ménière's disease patients caused otolith organ dysfunction, mainly in the saccule. The number of Ménière's disease patients with abnormal ocular vestibular evoked myogenic potentials was low (19%), and they also had abnormal utricular induced linear vestibulo-ocular reflexes.

[Endolymphatic hydrops detected with inner ear gd contrast-enhanced MRI; comparison between administration routes or with ECochG or glycerol test].

OBJECTIVE: Gadolinium (Gd) contrast-enhanced MRI has recently been introduced to clinical practice to detect endolymphatic hydrops. However, since the image depends on the hardware, pulse sequence or the way of Gd administration, the protocol and the evaluating criteria for hydrops on MRI have not yet been standardized. In this study, we assessed the usefulness of the hydrops detection by MRI following the intratympanic or intravenous Gd administration methods, and compared these findings with the electrocochleography and glycerol test. METHODS: MRI was taken in 27 patients with Meniere's disease or delayed endolymphatic hydrops. All patients had frequent episodes of vertigo attacks which were clinically considered as of unilateral ear origin. Two types of Gd administration were used; injection into the tympanic cavity in 17 patients or intravenous injection in 10 patients. Axial 2D-FLAIR images were obtained with a 3.0T MRI unit, 24 and 4 h after intratympanic or intravenous administration, respectively. The endolymphatic space was detected as a low signal intensity area, while the surrounding perilymphatic space showed high intensity with Gd contrast. Those cases in which low signal areas corresponding to the cochlear duct could be clearly noticed, were classified as cochlear hydrops. When the greater part of the vestibule was occupied by a low signal area in more than half of the images, it was classified as vestibular hydrops. RESULTS: Endolymphatic hydrops was detected in 88% (15/17 cases) by the intratympanic Gd administration method, and 90% (9/10) by the intravenous method. In the contralateral ears, 20% (2/10) showed hydrops, detected by the intravenous method. ECochG and the glycerol test were difficult when the hearing of the patient was severely impaired. Positive results of EcochG and the glycerol test were obtained only in 15 and 6 cases, respectively. However, as far as the waves could be obtained, ECochG showed a high detection rate of 88% (15/17) in the affected ear. In those cases in which both MRI and EcochG could be obtained, including both ears, the results were matched in 78% (21/27ears). CONCLUSION: For the qualitative detection of hydrops, intratympanic and intravenous Gd administration methods were equivalent. Inner ear Gd contrast-enhanced MRI had higher efficacy in the detection of hydrops than the conventional tests.

Genetic variants of cancer­associated genes analyzed using next­generation sequencing in small sporadic vestibular schwannomas.

Vestibular schwannoma (VS) is the most common tumor of the cerebellopontine angle. Despite the increasing diagnosis of sporadic VS over the past decade, the use of traditional microsurgeries to treat VS has decreased. This is likely a result of the adoption of serial imaging as the most common initial evaluation and treatment strategy, especially for small-sized VS. However, the pathobiology of VSs remains unclear, and elucidating the genetic information of tumor tissue may reveal novel insights. The present study performed a comprehensive genomic analysis of all exons in the key tumor suppressor and oncogenes from 10 small (<15 mm) sporadic VS samples. The evaluations identified NF2, SYNE1, IRS2, APC, CIC, SDHC, BRAF, NUMA1, EXT2, HRAS, BCL11B, MAGI1, RNF123, NLRP1, ASXL1, ADAMTS20, TAF1L, XPC, DDB2 and ETS1 as mutated genes. The current study could not draw any new conclusions about the relationship between VS-related hearing loss and gene mutations; however, it did reveal that NF2 was the most frequently mutated gene in small sporadic VS.

Examination of risk factors for postoperative vestibular symptoms in patients with cholesteatoma.

BACKGROUND: In cholesteatoma, the prognosis of tympanoplasty has been well discussed in terms of hearing outcomes and residual or recurrent lesions. Postoperative dizziness and vertigo are major complications of tympanoplasty; however, few reports are available. AIMS/OBJECTIVES: We investigated each condition of cholesteatoma postoperative vestibular risk using the STAM system and staging published by EAONO/JOS, as well as findings on bony destruction. MATERIAL AND METHODS: From April 2010 to March 2021, 156 patients (166 ears) with cholesteatoma who underwent primary microscopic tympanoplasty at our hospital were registered. Subjective vestibular symptoms were recorded the day after surgery. RESULTS: Postoperative vestibular symptoms were observed in 13.9% of subjects. All of them were stage II and had both attic and mastoid lesions. Attic (p < .05) and mastoid (p < .01) lesions were risk factors. Multivariate analysis showed that significant differences were found in past histories of vestibular symptoms (p < .05) and exposure of the dura mater (p < .01). CONCLUSIONS AND SIGNIFICANCE: In the exposed dura group, the length of the prominence of the lateral semicircular canal to the middle cranial fossa dura was significantly shorter than that of the non-exposed group (p < .01). Narrow working space and downward operation may increase vestibular risk.

How long do tympanostomy ventilation tubes last in pediatric patients with otitis media with effusion or adhesion? A study using Kaplan-Meier survival analysis.

OBJECTIVE: The purpose of this study was to evaluate the functional duration and survival rate of tympanostomy ventilation tubes and the complications associated with their use in pediatric patients who underwent tube insertion for otitis media with effusion (OME). Complications were analyzed including recurrence and tympanic membrane perforation after the tube removal or extrusion. METHODS: Altogether, 447 ears from 234 pediatric patients younger than 15 years of age were studied retrospectively. All patients had undergone long-term tympanostomy ventilation tube: the Goode T-tube insertion for OME at the Osaka Women's and Children's Hospital, which is the pediatrics specialty hospital between April 2014 and March 2016. They were typically followed up every 3-4 months or more frequently if necessary due to otorrhea or tube infection. Subsequently, the tube duration, survival rates of the tube especially at 22 months after insertion defined as "full-term placement", and the rates of recurrence and perforation were calculated and statistically evaluated. RESULTS: Of 447 ears, 335 ears from 184 patients underwent their first tube insertion, and 112 ears from 64 patients underwent their second or subsequent tube insertion within the targeted period. Two hundred ears from 106 patients were associated with a cleft palate. The survival rate at full-term placement was 51.7%. The recurrence rate was 56.3%, and the rate of the tympanic perforation was 8.5%. CONCLUSIONS: Approximately half of the tubes survived for 22 months. The perforation rate was relatively low; however, recurrence of OME was seen in more than half the ears.

The effect of cochlear implants on cognitive function in older adults: A prospective, longitudinal 2-year follow-up study.

OBJECTIVES: It is shown that eliminating hearing loss in mid-life may reduce the risk for deterioration in cognitive function. Cochlear implantation (CI) is the only available therapy that can eliminate hearing loss in patients who suffer from profound sensorineural hearing loss. This suggests there may be positive effects of hearing level on cognition in older adults following CI. Therefore, the purpose of this study is to clarify whether cognitive function can be improved or maintained using cochlear implants in older adult patients with hearing impairments. METHODS: Data for patients that underwent CI surgery for profound bilateral sensorineural hearing loss were collected prospectively. Patients aged 65 years and older were recruited at our university hospital from 2013 to 2017. Twenty-one patients (age range: 65-80 years) were included in this study. The primary outcome measurement was the change in cognitive function three points assessed by Mini-Mental State Examination (MMSE): preoperatively, and at 1 and 2 years after surgery. The secondary outcome measurements were the followings; the Nijmegen Cochlear Implant Questionnaire (NCIQ), the Self-Rating Depression Scale (SDS), and hearing and speech recognition threshold assessment before CI, and 1 and 2 years after CI. Differences in MMSE scores were compared for statistical significance using the Friedman test. The Wilcoxon signed-rank test was used as a post hoc test. Possible correlations between MMSE scores and NCIQ subdomain scores 2 years after surgery were evaluated with Spearman's tests. Statistical significance was defined as a p-value <0.05. RESULTS: CI recipients showed significant improvement in MMSE scores. This improvement peaked 1 year after CI surgery. The postoperative MMSE score was correlated with the NCIQ speech production score but not with the other five NCIQ subdomains. There was no correlation between MMSE score and speech recognition. CONCLUSION: Speech production is important to improve cognitive function after CI, and this improvement peaked 1 year after CI. Although severe or profound hearing loss in older adults worsens the natural course of cognitive function decline, CI has positive impacts on cognitive function even if MMSE scores decrease 1 year after the peak (i.e., 2 years after CI). Talking with others based on hearing is crucial to improve cognitive function. We should encourage older adult patients to take many opportunities to talk with others after CI surgery.

Machine Learning Technique Reveals Prognostic Factors of Vibrant Soundbridge for Conductive or Mixed Hearing Loss Patients.

OBJECTIVES: Vibrant Soundbridge (VSB) was developed for treatment of hearing loss, but clinical outcomes vary and prognostic factors predicting the success of the treatment remain unknown. We examined clinical outcomes of VSB for conductive or mixed hearing loss, prognostic factors by analyzing prediction models, and cut-off values to predict the outcomes. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary care hospital. PATIENTS: Thirty patients who underwent VSB surgery from January 2017 to December 2019 at our hospital. INTERVENTION: Audiological tests were performed prior to and 3 months after surgery; patients completed questionnaires 3 months after surgery. MAIN OUTCOME MEASURES: We used a multiregression and the random forest algorithm for predictions. Mean absolute errors and coefficient of determinations were calculated to estimate prediction accuracies. Coefficient values in the multiregression model and the importance of features in the random forest model were calculated to clarify prognostic factors. Receiver operation characteristic curves were plotted. RESULTS: All audiological outcomes improved after surgery. The random forest model (mean absolute error: 0.06) recorded more accuracy than the multiregression model (mean absolute error: 0.12). Speech discrimination score in a silent context in patients with hearing aids was the most influential factor (coefficient value: 0.51, featured value: 0.71). The candidate cut-off value was 36% (sensitivity: 89%, specificity: 75%). CONCLUSIONS: VSB is an effective treatment for conductive or mixed hearing loss. Machine learning demonstrated more precise predictions, and speech discrimination scores in a silent context in patients with hearing aids were the most important factor in predicting clinical outcomes.

Platform posturography of patients with peripheral vestibular dysfunction in the non-acute phase of vertigo.

OBJECTIVE: Posturography (PG) shows various patterns corresponding to a patient's equilibrium condition; however, PG is not useful for the differential diagnosis of peripheral vestibular diseases (PVDs). The aim of this study was to identify parameters of PG that can distinguish between PVDs. METHODS: The differences in PG parameters between PVDs were evaluated retrospectively. Two hundred and two patients with Ménière's disease (MD), 154 patients with benign paroxysmal positional vertigo (BPPV), 20 patients with sudden sensorineural hearing loss with vertigo (SSNHLwV), and 31 patients with vestibular neuritis (VN) underwent PG during the non-acute phase of vertigo, from January 2010 to March 2017. RESULTS: The velocity of body oscillation of BPPV patients with eyes open and closed were significantly faster than those of MD patients with eyes open (p < 0.001) and closed (p = 0.033). The velocity of body oscillation of VN patients with eyes open was significantly faster than that of MD patients with eyes open (p = 0.0083). There were no significant differences among the other PG parameters between PVDs. Although there were significant differences among the velocity with eyes open and closed between males and females (eye open: p = 0.0009, eye close: p < 0.0001), there was no significant difference in the ratio of males to females among PVDs (p = 0.1834). Therefore, the ratio did not influence the difference in velocity among PVDs. Patient age correlated with the velocity with eyes open (p < 0.001) and with eyes closed (p < 0.001). Post-hoc analysis revealed significant differences in patient age, and comparisons of MD and BPPV, MD and SSNHLwV, BPPV and VN, and VN and SSNHLwV. Therefore, we performed multiple regression analysis to determine whether the significant differences in the velocity of body oscillation among PVDs were caused by the difference in age distribution between PVD groups, rather than by differences in the PVDs themselves. There were correlations between age and the velocity of body oscillation with eyes open (p < 0.001) and with eyes closed (p < 0.001). There also were correlations between MD or VN and the velocity of body oscillation with eyes open (p = 0.0194). CONCLUSION: There were significant differences in the velocity of body oscillation with eyes open between MD and VN patients. The difference between MD and VN was significant regardless of the age distribution. To distinguish between MD and VN, the velocity of body oscillation with eyes open is a useful PG index.

Modulation of neuronal activity after spinal cord stimulation for neuropathic pain; H(2)15O PET study.

Spinal cord stimulation (SCS) is an effective therapy for chronic neuropathic pain. However, the detailed mechanisms underlying its effects are not well understood. Positron emission tomography (PET) with H(2)(15)O was applied to clarify these mechanisms. Nine patients with intractable neuropathic pain in the lower limbs were included in the study. All patients underwent SCS therapy for intractable pain, which was due to failed back surgery syndrome in three patients, complex regional pain syndrome in two, cerebral hemorrhage in two, spinal infarction in one, and spinal cord injury in one. Regional cerebral blood flow (rCBF) was measured by H(2)(15)O PET before and after SCS. The images were analyzed with statistical parametric mapping software (SPM2). SCS reduced pain; visual analog scale values for pain decreased from 76.1+/-25.2 before SCS to 40.6+/-4.5 after SCS (mean+/-SE). Significant rCBF increases were identified after SCS in the thalamus contralateral to the painful limb and in the bilateral parietal association area. The anterior cingulate cortex (ACC) and prefrontal areas were also activated after SCS. These results suggest that SCS modulates supraspinal neuronal activities. The contralateral thalamus and parietal association area would regulate the pain threshold. The ACC and prefrontal areas would control the emotional aspects of intractable pain, resulting in the reduction of neuropathic pain after SCS.

Frequency-velocity mismatch: a fundamental abnormality in parkinsonian gait.

Gait dysfunction and falling are major sources of disability for patients with advanced Parkinson's disease (PD). It is presently thought that the fundamental defect is an inability to generate normal stride length. Our data suggest, however, that the basic problem in PD gait is an impaired ability to match step frequency to walking velocity. In this study, foot movements of PD and normal subjects were monitored with an OPTOTRAK motion-detection system while they walked on a treadmill at different velocities. PD subjects were also paced with auditory stimuli at different frequencies. PD gait was characterized by step frequencies that were faster and stride lengths that were shorter than those of normal controls. At low walking velocities, PD stepping had a reduced or absent terminal toe lift, which truncated swing phases, producing shortened steps. Auditory pacing was not able to normalize step frequency at these lower velocities. Peak forward toe velocities increased with walking velocity and PD subjects could initiate appropriate foot dynamics during initial phases of the swing. They could not control the foot appropriately in terminal phases, however. Increased treadmill velocity, which matched the natural PD step frequency, generated a second toe lift, normalizing step size. Levodopa increased the bandwidth of step frequencies, but was not as effective as increases in walking velocity in normalizing gait. We postulate that the inability to control step frequency and adjust swing phase dynamics to slower walking velocities are major causes for the gait impairment in PD.

Comparison of furosemide-loading cervical vestibular-evoked myogenic potentials with magnetic resonance imaging for the evaluation of endolymphatic hydrops.

BACKGROUND: Furosemide-loading cervical vestibular-evoked myogenic potential (FVEMP), in which vestibular function is improved via diuretics-induced dehydration, can be used to estimate the presence of endolymphatic hydrops, one characteristic of Menière's disease. Inner ear magnetic resonance imaging (MRI) can also reveal endolymphatic hydrops.Aims/Objective: This study aimed to compare and confirm the usefulness of these two examination methods for the diagnosis of Menière's disease. METHODS: Twenty patients with definite unilateral Menière's disease were included. All subjects underwent both, FVEMP and inner ear MRI examinations. The results were then compared statistically between the affected and contralateral ears and among the methods. RESULTS: FVEMP and inner ear MRI of the cochlea, saccules, and utricles yielded positive results indicative of endolymphatic hydrops in 55.0%, 60.0%, 45.0%, and 45.0% of cases, respectively. The results of FVEMP were more consistent with those of the cochlea (κ = 0.8) than with those of the saccules or utricles by inner ear MRI (κ = 0.6). CONCLUSIONS: FVEMP appears to be a good and minimally invasive option for evaluating endolymphatic hydrops. However, the combination of FVEMP and inner ear MRI may yield even more accurate evaluations of endolymphatic hydrops.

Prevalence of potential candidates for electric-acoustic stimulation implant in a hearing-impaired population.

OBJECTIVE: To estimate the prevalence of potential electric-acoustic stimulation (EAS) implant candidates in a hearing-impaired population through a review of auditory examinations. METHODS: In total, 7356 patients underwent audiometric examination in our department between 2011 and 2014. The prevalence of patients meeting the audiometric criteria for EAS and standard cochlear implant (CI) was assessed. RESULTS: The percentage of EAS implant candidates meeting the pure-tone audiometric criteria was 0.71% (n=34) among the hearing-impaired individuals (n=4758) examined in our department, whereas 2.52% (n=120) met the criteria for standard CI. Among the 34 EAS implant candidates, 2 individuals (5.83%) received EAS implant surgery after approval of the EAS device in Japan. CONCLUSIONS: There was a lower prevalence of EAS implant candidates than standard CI candidates. Nevertheless, healthcare professionals should carefully examine the audiograms of patients with high frequency hearing loss with regard to meeting the indication criteria for EAS implant. This will enable patients to gain access to adequate information relating to further examinations and treatment options.

Three-dimensional analysis of the vestibulo-ocular reflex and the ability to distinguish the direction of centripetal acceleration in humans during eccentric rotation with the right ear facing downwards.

This study was conducted to evaluate the linear vestibulo-ocular reflex (lVOR) mediated by the saccule, and to investigate the relationship between the lVOR and the ability to distinguish the direction of centripetal acceleration during centric and eccentric rotation. Participants sat on a chair in darkness, with the right ear facing downwards, either directly above the center of rotation, or with their nose out, nose in, right shoulder out, or left shoulder out against the center of rotation (eccentric rotation). Participants were given no information about the chair position, and were rotated sinusoidally at 0.1-0.7 Hz. Three-dimensional eye movements during rotation were analyzed. Participants were asked to describe the position of the chair after rotation. Correctly reporting the five possible chair positions requires recognition of the direction of centripetal acceleration. We analyzed the rate of correct answers to assess participants' ability to identify the direction of centripetal acceleration. lVOR mediated by the saccule was observed only at high rotational frequencies. The rate of correct answers was higher at high rotational frequencies than that at low rotational frequencies. These results indicate that high rotational frequency is important for both lVOR mediated by the saccule and distinguishing the direction of centripetal acceleration.

Osteoclasts Modulate Bone Erosion in Cholesteatoma via RANKL Signaling.

Cholesteatoma starts as a retraction of the tympanic membrane and expands into the middle ear, eroding the surrounding bone and causing hearing loss and other serious complications such as brain abscess and meningitis. Currently, the only effective treatment is complete surgical removal, but the recurrence rate is relatively high. In rheumatoid arthritis (RA), osteoclasts are known to be responsible for bone erosion and undergo differentiation and activation by receptor activator of NF-κB ligand (RANKL), which is secreted by synovial fibroblasts, T cells, and B cells. On the other hand, the mechanism of bone erosion in cholesteatoma is still controversial. In this study, we found that a significantly larger number of osteoclasts were observed on the eroded bone adjacent to cholesteatomas than in unaffected areas, and that fibroblasts in the cholesteatoma perimatrix expressed RANKL. We also investigated upstream transcription factors of RANKL using RNA sequencing results obtained via Ingenuity Pathways Analysis, a tool that identifies relevant targets in molecular biology systems. The concentrations of four candidate factors, namely interleukin-1ß, interleukin-6, tumor necrosis factor α, and prostaglandin E2, were increased in cholesteatomas compared with normal skin. Furthermore, interleukin-1ß was expressed in infiltrating inflammatory cells in the cholesteatoma perimatrix. This is the first report demonstrating that a larger-than-normal number of osteoclasts are present in cholesteatoma, and that the disease involves upregulation of factors related to osteoclast activation. Our study elucidates the molecular basis underlying bone erosion in cholesteatoma.

Change in endolymphatic hydrops 2 years after endolymphatic sac surgery evaluated by MRI.

OBJECTIVE: This study was performed to determine whether endolymphatic sac surgery improves vestibular and cochlear endolymphatic hydrops 2 years after sac surgery and to elucidate the relationship between the degree of improvement of endolymphatic hydrops and the changes in vertigo symptoms, the hearing level, and the summating potential/action potential ratio (-SP/AP ratio) by electrocochleography (ECochG) in patients with Ménière's disease (MD). METHODS: Twenty-one patients with unilateral MD who underwent sac surgery were included in this study. All patients underwent gadolinium-enhanced magnetic resonance imaging (Gd-MRI) before and 2 years after sac surgery. We evaluated the difference in vestibular and cochlear endolymphatic hydrops between before and after surgery in both ears and compared these findings with the frequency of vertigo attacks, hearing level, and ECochG findings. RESULTS: In affected ears, the presence of vestibular endolymphatic hydrops and the frequency of vertigo attacks significantly decreased after surgery. However, affected ears showed no significant improvement in the presence of cochlear endolymphatic hydrops or the -SP/AP ratio by ECochG; there was also no significant improvement or deterioration in the hearing level. CONCLUSION: The present findings suggest that sac surgery reduces vestibular endolymphatic hydrops and prevents aggravation of cochlear endolymphatic hydrops, and these changes lead to a reduction of vertigo attacks and suppress the progression of hearing impairment associated with vertigo attacks.

Relative contribution of walking velocity and stepping frequency to the neural control of locomotion.

Stepping frequency is tightly coupled to walking velocity during natural locomotion. In a recent model, we demonstrated that walking velocity determines stride frequency, governs the active feedback control of the swing and determines the swing phase dynamics that governs foot movement. Here, we questioned whether the swing phase dynamics reflect independent effects of stride frequency and walking velocity. Foot movements were measured with a motion detection system (Optotrak) while subjects walked at 0.6-2.1 m/s on a treadmill. Stepping frequencies of 1.3-2.8 Hz were generated with pacing cues at each walking velocity. In the 'iso-velocity' condition, peak forward toe velocity during the swing phases was related to walking velocity and did not vary with alterations in stride frequency. In the 'iso-frequency' condition, in contrast, stepping frequency altered the relationship between toe acceleration and toe position in the fore-aft direction. The cycle frequency, main sequence (peak velocity vs. amplitude) relationships, and the shape of the phase-plane trajectories of the swing phases also reflected this relationship. The data were modeled by decoupling stepping frequency from walking velocity, while maintaining active feedback control dependent on frequency. The latter predicted both the dominant shape of the phase plane trajectories and the main sequence relationships. Thus, according to the model, walking velocity and stride frequency are independent central variables that control the dynamics of the swing phases and stepping. The ability to decouple stride frequency from walking velocity may help in navigating over uneven terrain or when executing curved trajectories while maintaining a constant velocity.

Brain responses during the first desire to void: a positron emission tomography study.

OBJECTIVES: First desire to void (FDV) is defined as the first feeling that would lead the patient to pass urine. The aim of the present study is to identify the brain regions activated during FDV. METHODS: Six healthy right-handed male volunteers, aged 31-40 years, agreed to participate in this study. Rather than inserting a urethral catheter, we used a urinary volume monitoring unit and a self-adhesive external condom catheter for this study. Positron emission tomography (PET) scans obtained in the FDV and post-voiding (absence of urge to void) (REST) states were analyzed and compared. RESULTS: First desire to void state was associated with increased blood flow in the right and left cerebellum, right parahippocampal gyrus (Brodmann area [BA] 30), left superior frontal gyrus (BA9), and left cingulate gyrus (BA32). Rest state was associated with decreased blood flow in the right superior temporal gyrus (BA22), right uncus (BA28), right cingulate gyrus (BA32), left middle temporal gyrus (BA21), and left medial frontal gyrus (BA25). According to region of interest analysis, regional cerebral blood flow of the periaqueductal grey and pons was significantly increased at FDV as opposed to REST. CONCLUSIONS: We located possible brain activity associated with the FDV sensation. Combined activation of the right and left cerebellum, parahippocampal gyrus, superior frontal gyrus, and left cingulate gyrus could be associated with FDV.

[Implantation of a vibratory mass transducer on the round window: a report of two cases].

The Vibrant Soundbridge (VSB, Med-El, Austria) is a semiimplantable hearing aid usually attached to the long process of the incus to vibrate the ossicular chain in patients with moderate to severe mixed hearing loss. We implanted a VSB vibratory transducer on the round window membrane of the left ear in two cases not treated effectively by tympanoplastic surgeries. Pure tone audiography did not differ significantly in the two cases pre- or postoperatively, indicating that the small mass transducer does not adversely affect middle-ear vibration. Postoperative hearing thresholds with VSBs were similar to those when patient 1 wore an air-conductive hearing aid and patient 2 wore a bone-anchored hearing aid (BAHA). VSB implantation on the round window could thus potentially benefit many patients with mixed hearing loss.

Serum Fibrinogen as a Prognostic Factor in Sudden Sensorineural Hearing Loss: A Meta-analysis.

OBJECTIVE: High blood viscosity has been proposed as a mechanism for sudden sensorineural hearing loss (SSNHL); however, the relationship between blood markers of fibrinolysis or coagulation and severity or prognosis of SSNHL is still unclear. The aim of this study is to investigate the relationship between serum fibrinogen and SSNHL. DATA SOURCES: PubMed and Scopus were searched for English language articles using the following keywords: SSNHL, sudden hearing loss, sudden deafness, idiopathic hearing loss or idiopathic sensorineural hearing loss, and fibrinogen. STUDY SELECTION: The articles in the study related to SSNHL and provided data about the serum fibrinogen level. DATA EXTRACTION: The data included patient profiles, fibrinogen level, recovery, and treatment modality. DATA SYNTHESIS: Nineteen articles were selected. The aggregated data were analyzed using the random effect model. Two articles that included the fibrinogen level with recovery rates were analyzed for the relationship between the fibrinogen level and recovery. CONCLUSIONS: The average fibrinogen level was 318 ±â€Š8.5 mg/dl (mean ±â€Šstandard error, within normal range). There was no difference in the fibrinogen level between SSNHL patients and the control group. The fibrinogen level of the recovery group was lower than that of the no recovery group. This showed that a high fibrinogen level was associated with poor prognosis, and it could be related to the severity of the pathological change rather than being the cause of the SSNHL. SSNHL includes various pathologies; therefore, the appropriate therapy should be selected based on each condition.