Effect of conductive hearing loss on the vestibulo-collic reflex

The vestibulo-collic reflex represents a promising test for evaluating the integrity of otolith function. We have investigated the threshold of this response in a group of normal subjects, and the effect of a conductive hearing loss. A positive response was recorded in 31 of 32 normal subjects. The threshold of the vestibulo-collic reflex varied from 80 to 97 dBHL in these subjects with a 95% response rate at a threshold at96 dBHL. A total of 23 ears with a conductive hearing loss in 17 patients were also investigated. The average conductive hearing loss (at 0.5, 1, 2 and 4 kHz) ranged from 8.75 to 40 dBHL (average24.46 dBHL). A positive response was recorded in only two ears. Therefore, the vestibulo-collic reflex has a high stimulus threshold which is dependant on reliable transmission of the click stimulus to the inner ear thus limiting is clinical use.     

Effect of stimulation repetition rate on galvanic-evoked vestibulo-collic reflexes

Conclusion Taking examination time and patient compliance into consideration, we propose that 5 Hz is the optimal stimulation rate of galvanic vestibular-evoked myogenic potentials for clinical use.

Objectives To evaluate the influence of stimulation repetition rate on galvanic-evoked vestibulo-collic reflexes and to propose the optimal stimulation rate for clinical use.

Material and methods Both ears of 30 healthy adults were tested at 5 different galvanic stimulation rates (1, 3, 5, 7 and 9 Hz) in a random order.

Results Responses were evident in all 60 ears only at 5 Hz; some ears showed no response at the other frequencies. The relative amplitudes in individual ears were higher at 1, 3 and 5 Hz than at 7 and 9 Hz. Comparison of the latencies of p13g and n23g showed no significant difference among the five stimulation rates.     

Caloric response and postural control in patients with nasopharyngeal carcinoma after radiotherapy

Since radiotherapy is the treatment of choice for nasopharyngeal carcinoma, the influence of irradiation on the temporal bone is of great concern for these patients. In this study, the caloric test and posturography were used to investigate vestibular function in 41 irradiated patients with nasopharyngeal carcinoma. Caloric testing showed a high incidence of canal paresis; five unilateral and 10 bilateral. Factors such as middle ear effusion had no significant effect on the occurrence of canal paresis. Posturography showed no difference from the control group. The authors conclude that the influence of irradiation on the vestibular apparatus of patients with nasopharyngeal carcinoma might result in a canal paresis, while postural control is preserved. Central compensation may play an important role in the postural control of these patients.     

Feasibility and effectiveness of providing vestibular rehabilitation for dizzy patients in the community

Since the majority of people with dizziness in the community are never referred for specialist testing and treatment, the purpose of this study was to investigate whether it was desirable and feasible to provide vestibular rehabilitation for this patient population. Demand for therapy was assessed by a survey of 9198 working age people randomly sampled from six general practices. One in 10 respondents reported current, handicapping dizziness, but fewer than 2% of those with dizziness severe enough to merit treatment proved suitable and willing to attend hospital for testing and rehabilitation. Nevertheless, vestibular rehabilitation was clearly beneficial for the 16 patients who completed the therapy programme, as their scores on measures of symptoms, disability, handicap and postural stability improved significantly post-therapy to near-normal levels. We conclude that there is a need for provision of vestibular rehabilitation in primary care for patients with dizziness in the community.     

Matrix metalloproteinase-2 and Matrix metalloproteinase-9 in cholesteatoma and deep meatal skin

A qualitative and quantitative study of the presence of Matrix metalloproteinase-2 (MMP-2) and Matrix metalloproteinase-9 (MMP-9) in cholesteatoma was performed. Ten cholesteatoma and four deep meatal skin specimens were analysed for gelatinase activity at molecular weights corresponding to MMP-2 and MMP-9 using Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS PAGE) Zymography. Gelatinase activity at 72 kDa and 92 kDa was investigated. Western blotting was employed using primary monoclonal antibodies to provide a qualitative assessment of MMP-2 and MMP-9. Non-parametric data analysis using the Mann–Whitney U test did not show a significant difference in expression of MMP-2 (P = 0.51) or MMP-9 (P = 0.14) between the two tissue types. Western blotting showed the presence of both MMP-2 and MMP-9 in the majority of specimens, both cholesteatoma and deep meatal skin.     

A prospective study of speech and voice rehabilitation after total laryngectomy with the low-resistance Groningen,Nijdam and Provox voice prostheses

In a prospective study the Groningen, Nijdam, and Provox voice prostheses were evaluated with respect to speech and voice rehabilitation. At ≈ 1, 4, and 10 months after operation, patients were submitted to a standardized speaking task to evaluate phonatory skills (phrase length, phonation duration, dynamics on tone, dynamics on sentence, speech rate and availability of sound), speech quality (fluency and overall intelligibility), voice quality and stoma technique (stoma noise). Tracheoesophageal speech rehabilitation proved to be successful in 94–100% of patients, as measured at ≈ 10 months after operation. Furthermore, no significant overall differences were found between the three prostheses. There was a significant improvement in time for speech rate and stoma noise. As for the time effects (e.g. improvement in performance over time) no differences between the three prostheses were found.     

Software for subjective visual vertical assessment: an observational cross-sectional study

Spatial orientation in relation to the gravitational axis is significantly important for the maintenance of the posture, gait and for most of the human's motor activities. The subjective visual vertical exam evaluates the individual's perception of vertical orientation.ObjectivesThe aims of this study were (1) to develop a virtual system to evaluate the subjective visual vertical exam, (2) to provide a simple tool to clinical practice and (3) to assess the subjective visual vertical values of h ealthy subjects using the new software. Study Design: observational cross-sectional study.MethodsThirty healthy volunteers performed the subjective visual vertical exam in both static and dynamic conditions. The exam consisted in adjusting a virtual line in the vertical position using the computer mouse. For the static condition, the virtual line was projected in a white background. For the dynamic condition, black circles rotated in clockwise or counterclockwise directions. Six measurements were taken and the mean deviations in relation to the real vertical calculated.ResultsThe mean values of subjective visual vertical measurements were: static ?0.372°; ± 1.21; dynamic clockwise 1.53° ± 1.80 and dynamic counterclockwise ?1.11° ± 2.46.ConclusionThis software showed to be practical and accurate to be used in clinical routines.     

Assessment of basal sound identification skills and communication abilities in profoundly deaf children fitted with hearing aids or a cochlear implant

Basal auditory functions and early verbal communication skills were examined in young, profoundly deaf children with hearing aids or a cochlear implant. The hearing aid users (n = 23) were subdivided on the basis of their (unaided) hearing thresholds into: group A (pure tone average (PTA) at 0.5, 1 and 2 kHz: 90–100 dB HL); group B (PTA: 100–110 dB HL); and group C (PTA > 110 dB HL). All the children with a cochlear implant (n = 20) had a profound sensorineural hearing loss with a PTA that exceeded 120 dB HL. Functional hearing was evaluated by means of basal sound identification. The child’s communication abilities with hearing aids or a cochlear implant were assessed using structured observations on the Scales of Early Communication Skills for Hearing Impaired Children. The basal auditory functions on a sound identification level improved over time in the cochlear implant users and groups A and B. Hardly any improvement was seen in group C. The performance of all the groups (either hearing aid or cochlear implant) on the Scales of Early Communication Skills for Hearing Impaired Children at 6 months after fitting the device and at later evaluations, was close to the average level for their age.     

Can event-related potentials be evoked by extra-cochlear stimulation and used for selection purposes in cochlear implantation?

To investigate whether electrically evoked event-related responses (P300) could be elicited by extra-cochlear stimulation, measurements were performed on a group of adults fitted with the single-channel extra-cochlear implant. To optimize measurement conditions, and because of the low number of subjects still using an extra-cochlear device in our cochlear implant programme, measurements were also performed on a group of experienced users fitted with the intra-cochlear Nucleus multichannel device. For reference purposes, subjects with normal hearing (control group) were also included in the study. Reproducible late latency responses (N1 and P2 peaks) were found in the five extra-cochlear implant users, while P300s were present in four out of these five subjects. The latencies were longer than those of the control group, but were similar to those obtained in the intra-cochlear implant group. Significant correlations were found for most N1, P2 and P300 measurements evoked by the tonal stimuli and by speech stimuli. The P300 amplitudes, evoked by either tonal or speech stimuli, appeared to be related to speech perception ability. This led to the conclusion that N1, P2 and P300 measurements may have potential as a clinical tool for preoperative prediction and postoperative evaluation of sound processing on a cortical level.     

Bipolar scissor tonsillectomy

We describe a new technique for tonsillectomy using dual-function scissors that cut and bipolar coagulate at the same time. The technique shortens operating time and decreases intra-operative blood loss. Forty patients had their tonsillectomy performed using this technique. The mean operating time was 5.5 min ( sd 2.1) and mean blood loss was 1.3 ml ( sd 3.6). All patients were able to eat and drink on the same postoperative day and all were discharged the following morning. None of the patients had primary haemorrhages and two patients (5%) had minor secondary haemorrhages. We found bipolar scissor tonsillectomy to be a safe technique that shortens surgery and minimises blood loss without causing increased postoperative morbidity.     

Does bismuth subgallate have haemostatic effects in tonsillectomy?

Previous studies have shown that bismuth subgallate added to gauze swabs in tonsillectomy reduces the time to achieve haemostasis and probably reduces the risk of postoperative haemorrhage. All these studies have used bismuth subgallate in combination with adrenaline. In this randomised clinical study we investigated the effect of bismuth subgallate alone. A total of 204 patients were randomised into two groups. One hundred and six patients had swabs with bismuth subgallate. In the control group (n = 98), plain swabs were used. Operating time, time to achieve haemostasis, peroperative blood loss, and incidence of postoperative haemorrhages were recorded. There were no significant differences between the two groups. We conclude that the evidence for using bismuth subgallate as a haemostatic agent in tonsillectomy is weak. The effect observed in previous studies can probably be ascribed to the effect of adrenaline.     

The epidermoid formation and its affinity to congenital cholesteatoma

The epidermoid formation was reinvestigated in stained step sections of foetal and neonatal temporal bones to assess its relationship to congenital cholesteatoma. Epidermoid formations were found in 88 of 211 temporal bones (42%) at from 12 weeks gestation to 6 months post-partum. The site was usually near the roof of the anterolateral epitympanum at an average of 389 μm anterior to the anterior edge of the tympanic membrane. Seven epidermoid formations however, were sited on the medial anterosuperior tympanic membrane surface. The mean surface diameter of epidermoid formations was 242 μm. Some were greater than 1500 μm, which approaches the size of small congenital cholesteatomas. They are often in proximity to a developmental epithelial fold which could close off to produce a cyst. These features support the concept that the epidermoid formation is a precursor of the small anterosuperior congenital cholesteatoma.     

Horizontal vestibulo-ocular reflex dynamics in acute vestibular neuritis and viral labyrinthitis: evidence of otolith-canal interaction

Objective To evaluate the dynamic properties of the horizontal vestibulo-ocular reflex (h-VOR) in the acute stage of two common labyrinthine diseases that provoke severe attacks of vertigo with spontaneous nystagmus: vestibular neuritis (vestibular loss alone) and viral labyrinthitis (cochleovestibular loss).

Material and Methods Sixty-three patients were investigated: 42 were diagnosed with vestibular neuritis and 21 with viral labyrinthitis. The h-VOR function was evaluated by conventional caloric and impulsive testing. A simplified model of vestibular function was used to analyze the vestibulo-ocular response to rotational stimulation.

Results The results showed a significant difference in h-VOR characteristics between the two pathologies. Patients with vestibular neuritis exhibited a strong horizontal semicircular canal deficit, but no h-VOR asymmetry between the two rotational directions. In contrast, patients with viral labyrinthitis demonstrated moderate canal paresis and a marked h-VOR deficit in rotation toward the affected ear.

Conclusions These findings support the hypothesis that the h-VOR dynamic asymmetry that occurs after an acute unilateral inner ear lesion is not due to canal dysfunction alone, but involves complex adaptive changes in the central VOR that may implicate the otolith system. Based on histopathologic and clinical differences in the two pathologies reported in the literature, we postulate that this otolith-canal interaction is mainly linked to the loss of saccular function.     

Streptomycin perfusion of the labyrinth in the treatment of Menière’s disease: a modified technique

The ideal surgical procedure for Menière’s disease would combine the high rate of vertigo control and the good hearing preservation of vestibular nerve section with the low morbidity of labyrinthectomy. Shea’s technique of streptomycin perfusion of the labyrinth has been modified by making an additional opening into the posterior semicircular canal in an effort to limit the amount of streptomycin going into the cochlea. Seventeen patients with definite Menière’s with poor hearing have had this procedure. Vertigo was controlled in 94% and the hearing preserved in 55%. Vestibular rehabilitation was not a problem. It is speculated that hearing preservation would be better if the procedure were not restricted to those with poor hearing. This method of destruction of the vestibular system carries the possibility of hearing preservation and maintains the possibility of cochlear implantation should this ever be required.     

Function of semicircular canals,utricles and saccules in deaf children

Objective To study vestibular function in deaf children.

Material and Methods In 36 deaf children the function of the semicircular canals, saccules and utricles was measured by means of caloric testing, recordings of vestibular-evoked myogenic potentials (VEMPs) and measurements of the subjective visual horizontal (SVH) at different body tilts, respectively.

Results In total, 30% of subjects had caloric hypo- or areflexia and 24% had a caloric asymmetry. VEMPs were weak or absent bilaterally in 22% of cases, and asymmetric in 19%. Regarding the utricle, 17% of subjects had a pathologically reduced perception of roll tilt to both sides and 25% had an asymmetry. In total, 30% of subjects were pathologic in all 3 tests and 30% were completely normal. Semicircular canal function correlated best with the function of the saccule. If hearing was better than 90 dB (pure-tone average of 0.5, 1.0 and 2.0 kHz) vestibular function was often normal. For hearing levels of 100–120 dB, otolith function declined significantly.

Conclusions Vestibular function tends to be preserved up to a point where hearing is nearly extinct. Hearing level correlates more closely with otolith function, especially that of the utricle, than with semicircular canal function.     

The impact of stimulation rates in vestibular evoked myogenic potential testing

Vestibular evoked myogenic potentials (VEMP) have been used in complementary otoneurological assessment, but the use of VEMP in clinical settings is limited. VEMPs can be used to assess vestibular function, particularly of the saccule, the inferior vestibular nerve, and/or the vestibular nucleus.ObjectiveTo verify the highest possible - and reliable - stimulation rate to obtain VEMPs.MethodThe VEMPs of 18 subjects were acquired using stimulation rates ranging between 5.1 and 40.8 stimuli per second. Study design: cross-sectional contemporary cohort study.ResultsLatencies were kept unaltered and amplitudes were progressively reduced as stimulation rates were increased. However, ANOVA and the Kruskal-Wallis test failed to find statistically significant differences between the tested parameters. The study further indicated that when stimulation rates of 5.1 and 10.2 stimuli per second were compared, no statistically significant differences were observed in latency.ConclusionThe highest reliable stimulation rate observed in the group of young adults with normal hearing included in this study was 10.2 stimuli per second.     

The vestibular system in the elderly: Clinical implications

Cell loss, changes in synapse morphology, electrophysiologic alterations, and changes in the supporting microenvironment have all been noted in portions of the vestibular systems of aged animals and humans. Increased variability with age is also a prominent finding in many studies. Quantitative vestibular testing in humans has shown alterations with age as well, but decline with aging is not a prominent feature of all measures, and many reported studies are methodogically flawed. The connection between these observed aging changes and the increased incidence of dizziness and falls in the elderly is unproven, however, and clinicians should search carefully for specific disease processes in their elderly patients who present with vestibular symptoms.     

The diagnosis of central vestibular disorders based on the complementary examination of the vestibulospinal reflex

Objectives:Stance and gait unsteadiness along with vertigo contribute to a central vestibular disorder.For objective analysis ultrasound-computer-craniocorpography(US-COMP-CCG)can be used.Aim of the study was to characterize the unsteadiness in central vestibular disorders and discuss the possible diagnostic usage of US-COMP-CCG.Methods and results:Hundred-and-ninety patients(70 male and 120 female,mean age±SD,58.94±15.27)suffering from central vestibular disorder and 230 healthy control patients(78 male and 152 female,mean age±SD,50.94±15.27)were enrolled.Stance and gait analysis was according to vestibulospinal tests of US-COMPCCG.IBM SPSS V24 software was used for statistical analysis.Mann-Whitney U test and Chi-square test were used,along with sensitivity and specificity categorization.The significance level was p<0.05.According to schematic and statistical analysis instability and postural sway were increased in the vertigo population and statistically significant difference was shown.Upon categorical analysis significant correlation was detected[standing test:longitudinal sway(p<0.00001),lateral sway(p<0.00001),forehead covering area parameters(p=0.0001);stepping test:longitudinal deviation(p=0.05),lateral sway(p=0.011)parameters].Conclusions:Clinicians should consider that postural instability is prominently present in this population and might be of a diagnostic importance.