Magnetic resonance imaging results in patients with central electronystagmography findings.

The objective of this study was to determine the findings on magnetic resonance imaging (MRI) in patients identified as having central vestibular abnormalities on electronystagmography (ENG) testing, to discuss the issue of 'gold standard' in the investigation of central oculo-vestibular system diseases and to present a model for understanding this area. A retrospective review of the case notes of patients (n = 23) found to have central ENG findings at vestibular assessment and for whom MRI scanning data was available was undertaken. Each patient underwent a full ENG evaluation, including gaze, ocular-motor and caloric testing, and MRI. Only seven of the patients with central ENG findings had abnormal MRI scans. Thus, the incidence of the identification of structural abnormality on MRI in patients with central ENG findings is low. These investigations are complementary in the investigation of balance disorder patients.

Positional vertigo as a first symptom of a cerebellopontine angle cholesteatoma: case report.

We report a case of a cerebellopontine angle cholesteatoma whose initial sign was benign paroxysmal positional vertigo (BPPV). Positional vertigo caused by a central pathology is extremely rare and is usually accompanied by other suspicious features. In this case, there were no additional neurotologic symptoms or signs. The only abnormalities were seen on Dix-Hallpike testing, but because they were not consistent with a diagnosis of BPPV, the decision was made to proceed to imaging. Diagnostic rigor is required when evaluating positional vertigo, as with all symptoms of imbalance, if such cases are not to be overlooked.

Recurrence of symptoms following treatment of posterior semicircular canal benign positional paroxysmal vertigo with a particle repositioning manoeuvre.

A consecutive series of 51 patients (34 females and 17 males) with posterior semicircular canal benign positional paroxysmal vertigo (BPPV) were treated with the modified Epley particle positioning manoeuvre (PRM). Follow-up data were available on all 51 patients. After one manoeuvre, 42 patients had a negative Dix-Hallpike test, and after a second manoeuvre, 8 of the remaining 9 patients had a negative Dix-Hallpike test (testing was conducted 1 to 2 weeks after the PRM was performed). Therefore, the overall short-term success rate after two manoeuvres was 50 of 51 patients (98%), which is similar to other series. A follow-up questionnaire to determine the incidence of recurrence of symptoms was administered after a minimum period of 30 weeks. Twenty-three patients reported a recurrence (or, in the case of the one treatment failure, persistence) of their symptoms (45%). Therefore, although virtually all patients can be treated successfully with the PRM, almost half of these patients can be expected to experience a further recurrence of symptoms. This long-term recurrence rate is higher than has previously been reported and is a significant factor clinicians must be aware of in their treatment of this condition. In particular, this finding emphasizes the need for patient counselling with regard to the likelihood of recurrence and access to follow-up treatment if recurrence occurs.

Hearing preservation in solitary vestibular schwannoma surgery using the retrosigmoid approach.

The results of 50 cases of vestibular schwannoma surgery with hearing preservation performed by the retrosigmoid approach at Addenbrooke's Hospital, Cambridge, during a 10-year period are presented. The hearing-preservation rate, using audiometric criteria set by others as "serviceable hearing" (Wade PJ, House W. Otolaryngol Head Neck Surg 1984;92:1184-93; Silverstein H, et al. Otolaryngol Head Neck Surg 1986;95:285-91; Cohen NL, et al. Am J Otol 1993;14:423-33) was 8% (4 of 50 cases). When the more stringent selection criteria of near-normal hearing and reporting criteria of socially useful hearing preservation (pure-tone average < 30 dB/speech discrimination score > 70%) is used, the hearing-preservation rate is 4.8% (1 of 21 cases). The only preoperative factor that may predict a favorable hearing-preservation outcome is normal auditory brain stem response morphology (Fisher's exact 2-tailed test, P < 0.001). The number of suitable candidates for hearing-preservation surgery are few. Reasonable indications for attempted vestibular schwannoma surgery with hearing preservation are discussed.

Does choice of hearing selection criterion and reporting criteria affect the hearing preservation rate in vestibular schwannoma surgery?

With increasing refinement in the surgery of vestibular schwannoma the aims of complete tumor removal and facial nerve preservation have been largely fulfilled. However, the reputation of and place for hearing-preservation surgery still remain uncertain. A major part of this uncertainty is the result of difficulties in interpretation of the various reported results of hearing-preservation surgery. Meaningful comparison between series is difficult because of the varied number of postoperative reporting criteria commonly in use today. Although it is acknowledged that the postoperative reporting criteria affect the hearing-preservation rates, what is not readily appreciated is that preoperative selection criteria for hearing-preservation cases can also significantly affect the success rate of hearing-preservation acoustic neuroma surgery. This article models the many possible outcomes of hearing-preservation schwannoma surgery by use of the previously reported Cambridge series as an illustrative example. With these models some understanding can be gained of the effect of choosing various preoperative and postoperative hearing criteria on the overall hearing-preservation success rate.

An investigation of the effect of structured teaching on a group of tinnitus patients after vestibular schwannoma removal.

OBJECTIVE: This study aimed to determine the effect of a structured lecture and discussion on the tinnitus handicap and tinnitus intensity experienced by a group of patients who had undergone surgical removal of a unilateral vestibular schwannoma. STUDY DESIGN: The study design was a prospective repeated measures trial. SETTING: The study was conducted on a support group for patients with vestibular schwannoma based on a University Hospital Department of Neuro-Otology. PATIENTS: Twenty-one members of a vestibular schwannoma support group who attended a meeting entitled, "Living with Tinnitus" participated. All patients had undergone a surgical removal of a unilateral sporadic vestibular schwannoma. INTERVENTION: A structured lecture and a discussion on the nature of tinnitus and how to live with it by an audiological scientist was performed. MAIN OUTCOME MEASURES: Score on the tinnitus handicap inventory (THI) and associated functional, emotional, and catastrophic subscales and a visual analog scale (VAS) rating of tinnitus intensity were measured. Both measures were taken before intervention and 6 months after intervention. All measures were self-administered. RESULTS: Of 21 patients attending the lecture, 19 completed both preintervention and postintervention measures. Mean age was 58 years (range, 35-74 years). No significant difference was seen between pre-THI and post-THI total score, subscale scores, or VAS score. No correlation between THI score, VAS score, age, and length of postoperative period was seen. Although preintervention THI and VAS scores were not significantly correlated, there was a significant correlation between THI total and VAS score after intervention and THI functional subscale and VAS score after intervention. The study group was compared with the validation group for THI: significant differences were seen between sample postintervention emotional score and validation emotional score and between sample catastrophic scores and validation catastrophic score. In each case, the sample scores were lower (less handicap) than the validation scores. CONCLUSIONS: This intervention did not make a significant difference to the THI score of the sample group. The fact that the sample group had significantly different tinnitus handicap than the validation group is of note and indicative that postoperative tinnitus in patients with vestibular schwannoma does not lead to as great an emotional and catastrophic handicap as in a general tinnitus group.

Effective anaesthesia for transtympanic electrocochleography.

The objective of this study was to quantify the anaesthetic effect of EMLA cream during transtympanic electrocochleography (TTECochG) and thereby to determine if the application of EMLA should be recommended in routine practice of electrocochleography (ECochG). ECochG provides useful information in patients with inner ear fluid disorders. A major concern regarding transtympanic positioning of the electrode in ECochG is patient discomfort. Previous work has suggested that EMLA cream may make this technique more tolerable to patients. A prospective randomized study was performed evaluating the discomfort associated with unilateral TTECochG in a group where EMLA cream was used to anaesthesize the tympanic membrane (n = 24), and in a group where no anaesthesia was used (n = 22). A statistically significant difference was evident between the discomfort ratings of the groups (P < 0.0001, Mann-Whitney U test), the discomfort being greater in the no anaesthesia group. EMLA cream has thus been shown to alleviate the level of discomfort associated with TTECochG and so to be an acceptable modification of this technique.

A clinical evaluation of head impulse testing.

The head impulse test is a simple clinical test comprising high acceleration head rotation. In the presence of a severe unilateral vestibular weakness the normal vestibulo-ocular reflex is replaced by a misalignment of the eye followed by a series of corrective saccades which are evident to the examiner. Previous reports have shown the high sensitivity of the head impulse test in detecting complete unilateral weakness, but indicate poor sensitivity for mild weaknesses. This prospective, blinded study examined the head impulse test in a general clinical population of balance disorder patients to examine the sensitivity and specificity of the test, and to determine the degree of vestibular weakness that is required before the test becomes positive. One hundred and fifty patients were examined and the head impulse test results were compared to results from bithermal caloric testing. Results show that the overall sensitivity of the head impulse test is 34% with a specificity of 100%. The test does not detect mild or moderate vestibular weaknesses but is very sensitive to the presence of a severe paresis (87.5%). Head impulse testing will not replace caloric testing but is a very useful adjunct to it.

Clinical acumen and vestibular schwannoma.

OBJECTIVE: This study aimed to quantify the atypical presentations of patients with vestibular schwannoma by applying the audiologic criteria for the treatment of patients to the Cambridge series of such tumors to show that clinical acumen is necessary for the effective screening of these tumors. STUDY DESIGN: This study was a retrospective case review of 473 patients with vestibular schwannoma. SETTING: The surgery was conducted at the Department of Otoneurological and Skull Base Surgery, University Hospital, Cambridge, a tertiary referral center. PATIENTS: A total of 473 patients with a unilateral sporadic vestibular schwannoma were studied. MAIN OUTCOME MEASURES: Measured were the principal presenting symptoms and the criteria for audiologic management. RESULTS: Of this series of patients, 89.3% had a principal presenting symptom that was typical of vestibular schwannoma (hearing loss: progressive or sudden, imbalance or tinnitus) and 10.7% had an atypical principal presenting symptom. This group of patients had significantly larger tumors (Mann-Whitney U test; tied p value = 0.0002), shorter length of history (tied p value < 0.0001), and better preserved hearing (tied p value < 0.001) than the typical otologic presentation group. These clinical correlates are related to tumor morphology, and it is hypothesized that the site of the neurilemmal-glial junction (medial or lateral) has an effect here. If the U.S. criteria for the treatment of a patient by an audiologist are applied to this series of patients, then 7 patients (1.5%) would not have had the diagnosis of vestibular schwannoma. If the U.K. criteria are applied, this number of missed tumors is 17 (3.6%). The addition of unilateral tinnitus as an indicator of the need for otologic investigation reduced the number of patients who might be missed to 2 (0.42%) for the U.S. cases and 5 (1.1%) for the U.K. cases. CONCLUSIONS: Of patients with vestibular schwannoma, 10.7% have an atypical principal presenting symptom, and this group of patients has significantly larger tumors than those patients who present typically. This finding is of particular relevance to the entry point of such cases to the healthcare system. A number of patients with vestibular schwannoma appear to pass the criteria for treatment by an audiologist without reference to an otologic opinion. These patients may not be investigated from an early stage with potential implications for increased morbidity.

An analysis of referral patterns for dizziness in the primary care setting.

BACKGROUND: The majority of balance disorders are non life-threatening and symptoms will resolve spontaneously. However, some patients require further investigation and many disorders may benefit from specialist treatment it is unclear whether appropriate identification and referral of this group of patients presently occurs. AIM: To review the management of patients with symptoms of dizziness within primary care. METHOD: A retrospective review of the management of 503 patients who visited their general practitioner (GP) complaining of dizziness between August 1993 and July 1995. Management was then compared with local criteria. RESULTS: On average, 2.2% of patients per year at the practices studied consulted their GP about dizziness, amounting to 0.7% of all consultations. The most common GP diagnosis was of an ear, nose, and throat (ENT) disorder (33.8%). Similarly, many of the 16% referred were directed to ENT (36%) specialists. The proportion of patients referred was significantly higher in those seeing their GP at least twice, those with symptoms lasting a year or more, or where there were additional symptoms associated with the dizziness, indicative of a cardiac, ENT, or neurological disorder. Compared with the local criteria, 17% of management decisions were deemed inappropriate. The major failing was not referring appropriate patients. This group comprised patients with chronic, non-urgent symptoms, and were significantly older than those appropriately referred. CONCLUSION: Patients with chronic symptoms of dizziness, particularly the elderly, are under-referred for specialist consultation and, therefore, do not have access to appropriate treatment regimes. This suggests a need for further training of GPs and evaluation of therapeutic needs of elderly dizzy patients.

A consideration of the effect of ear canal resonance and hearing loss upon white noise generators for tinnitus retraining therapy.

Tinnitus retraining therapy has been heralded as a major advance in the alleviation of tinnitus perception. A cornerstone of this technique is to use white noise produced by a white noise generator (WNG) over a period of several months in order to assist the patient to habituate to their tinnitus. There are three factors which influence the frequency spectrum of the perceived noise such that the perception of white noise from a WNG is unlikely. These factors are the actual spectrum of the emitted noise, the ear canal resonance of the patient and the hearing sensitivity of the patient. Advocates of tinnitus retraining therapy state that white noise is the optimal stimulation to assist habituation of tinnitus. This paper demonstrates that this optimal situation is unlikely to be achieved and that this may account for the long periods needed for patients to achieve benefit from the technique. The development of devices that allow for the above factors to be countered is suggested.

A randomized, controlled trial of the efficacy of a communication course for first time hearing aid users.

Many centres include a communication course as part of their auditory rehabilitation. These usually take the form of a small group and include discussion of the effects of hearing loss, use of the hearing aid, hearing tactics and lip reading. To investigate the efficacy of such a rehabilitation programme a randomized, controlled trial of a communication course was undertaken. All subjects were first time hearing aid users; handicap was measured using the Quantified Denver Scale of Communication Function (QDS) at the time of hearing aid fitting, and then 13 weeks later. All subjects had a hearing aid follow-up appointment, but the treatment group (n = 22) also underwent a four-week communication course, while the control group (n = 25) had no further rehabilitation. The reduction in handicap measured by the change in QDS was significantly greater for the treatment group than for the control group (Mann Whitney U test, tied p value = 0.014). This indicates that such a communication course is efficacious in reducing handicap. Further research is required to identify the populations that will benefit most from such a course.

A review of management of benign paroxysmal positional vertigo by exercise therapy and by repositioning manoeuvres.

Benign paroxysmal positional vertigo (BPPV) is a common condition that often resolves spontaneously, but can cause significant distress to a patient. Management of this condition includes no intervention, medication, surgery, physical exercises and more recently 'particle repositioning' manoeuvres. Repositioning manoeuvres aim to relocate free-floating particles from the posterior semicircular canal into the utricle where they will no longer cause vertiginous symptoms. This article describes the different exercises and repositioning manoeuvres in use and examines their efficacy. In the light of this review a management strategy for BPPV is suggested.

Audio-vestibular findings in meningioma of the cerebello-pontine angle: a retrospective review.

The aim of this study was the determination of the incidence of symptoms of audio-vestibular dysfunction and of abnormalities on audio-vestibular testing in patients found to have a unilateral meningioma of the cerebello-pontine angle (CPA). The case notes of 25 patients diagnosed with unilateral, sporadic and histologically proven CPA meningioma were retrospectively reviewed. The age range of this series was 31-71 years, with a mean age of 50 years. Two patients were male (eight per cent) and 23 were female (92 per cent). The mean length of history was 44.7 months. The distribution of tumour size was skewed toward larger tumours, with 15 cases (60 per cent) having tumours with a maximum diameter greater than 3.5 cm on imaging. Pure tone audiometry was normal in five cases (20 per cent), and no patients exhibited the high frequency sensorineural hearing loss that is characteristic of vestibular schwannoma. Speech audiometry was normal in 50 per cent of cases. Caloric testing was abnormal in 77 per cent of the 18 cases tested, whilst auditory brainstem responses (ABR) were abnormal in 100 per cent of the 18 cases who had sufficient hearing for this test to be possible. The presence of normal audiometry in patients with a proven CPA lesion indicates that, if in a protocol for investigation, asymmetry of hearing is mandatory then some pathology will be missed. Any suspicion of a CPA lesion warrants investigation even in the absence of hearing loss. The investigation of choice for the identification of CPA lesions has become magnetic resonance imaging (MRI). If this technique is not available then this study indicates that ABR is a suitable and sensitive investigation. It should be borne in mind however that the data in this study has been derived from a series of predominantly large tumours, and the sensitivity of ABR to smaller CPA meningiomata may fall, as is the case for vestibular schwannoma.

Audiovestibular results after surgery for cerebellopontine angle meningiomas.

Meningiomas are the second most common cerebellopontine angle (CPA) tumor. The reported rates of hearing preservation following surgical removal vary between 32% and 100%. There is only one recent report discussing vestibular function after CPA meningioma removal. In this series of 31 patients with CPA meningiomas, 16 patients had their tumors removed via the retrosigmoid approach. All 16 had audiovestibular assessment pre- and postsurgery and were the subjects of this study. Class A hearing is socially useful hearing and is defined as a pure tone average (PTA; average of 500 Hz and 1, 2 and 4 kHz) of < 30 dB and speech discrimination scores (SDS) of > 70%. Class B hearing is serviceable hearing, defined as PTA of < 50 dB and SDS of > 50%. Nine patients had class A hearing, and two had class B hearing presurgery. Socially useful hearing was preserved in six of nine (67%) patients in whom it was present before surgery, and serviceable or better hearing was preserved in eight of 11 (73%). Vestibular symptomatology and examination findings improved despite a decrease in the number of patients with intact caloric function postsurgery. Patients who retained vestibular function on caloric testing were symptomatically better than those who lost caloric function. These results confirm that excellent audiovestibular function is possible after CPA meningioma surgery.

Measurement of variability in sound field audiometry due to subject movement.

Sound field audiometry is used primarily for hearing assessment in young children and for functional hearing aid evaluation. It is important that measurements are accurate and reliable as they affect the management of patients. Most clinics use a substitution method for calibration and, as a result, if the subject moves from the calibrated test point, the sound pressure level (SPL) at the ears will vary as the sound field is very rarely uniform. This variation can result in inaccurate threshold estimation and increased test-retest variability. A commonly used method for evaluating the potential errors due to subject movement involves measuring the variation in SPL, with respect to the test point, at six points around the test point. This method makes assumptions about the sound field which may not be valid and could lead to an underestimation of the variation present. The aim of this investigation was to assess the accuracy of this method. Measurements of variation were taken with a microphone and repeated with a head and torso simulator (HATS) which was used to represent a test subject. The total degree of variation indicated by these two methods was compared. The microphone measurements indicated less variation than the HATS measurements. The differences were statistically significant but small in clinical terms. Assuming that the HATS is properly representative of the normal population, then this result indicates that simple microphone measurements are acceptable for normal clinical practice but that higher quality measurements are desirable for critical work.

The patient's perspective after vestibular schwannoma removal: quality of life and implications for management.

A postal survey was conducted, using a standardized quality of life questionnaire, of patients who had undergone surgery for removal of vestibular schwannoma between 1981 and 1992. Of 257 questionnaires, 227 (88%) were returned completed. The questionnaire was based on the European Organisation for Research into the Treatment of Cancer (EORTC) core questionnaire. A series of five functional gradings were used to assess the quality of life, and specific questions were also asked. The results were numerically scored and have been correlated with patient and tumor characteristics. There was a significant difference (p = .0001) between the subjective functional outcome for small and intracanalicular tumors when compared with tumors larger than 1.5 cm maximum diameter. However, there was no significant difference when tumors 1.5 to 2.5 cm in diameter were compared to larger tumors. Poor functional outcome did not correlate with the age of the patient, position in the series, or postoperative facial nerve motor function. There also was no significant difference when younger patients (age < 65 yr) were compared with older patients (age 65 - 76 yr). In general, the quality of life following vestibular schwannoma surgery was excellent. Patients with a poor functional outcome were evenly distributed over the medium and large tumor size groups, and patients with small tumors ( < or = 1.5 cm) had a significantly better outcome.

Referral patterns in vestibular schwannomas.

The investigation and treatment of vestibular schwannomas is an increasingly specialized area in which major advances have been seen over recent years. The effect of these advances on the referral patterns to a centre specializing in such surgery is reviewed. The proportion of referrals with a known diagnosis has increased substantially, allowing the specialist centre to focus on appropriate management rather than diagnosis. The vast majority of vestibular schwannomas are referred by otolaryngologists. The caseload referred by neurologists or neurosurgeons have different presenting symptoms. The incidence of vestibular schwannoma in the Cambridge district is found to be 1 per 50,000 population per year. This is a higher incidence than that recorded in other studies. This may be due to a tight diagnostic strategy and the high level of clinical awareness of the local general practitioners.

Patient comfort in audiological testing.

A questionnaire survey was conducted to investigate the relative comfort of a comprehensive range of diagnostic procedures. The mean comfort ranking and variability in comfort were examined. Pure tone audiometry and speech audiometry are the most comfortable tests, while caloric testing and transtympanic electrocochleography are the least comfortable. However, caloric testing and glycerol dehydration are not significantly different in comfort to magnetic resonance imaging (MRI), and brainstem evoked response testing is more comfortable than other diagnostic tests, including MRI. The reasons for these differences and the implications for diagnostic management are discussed.