Comparing Ocular Responses to Caloric Irrigation and Electrical Vestibular Stimulation in Vestibular Schwannoma.

Electrical Vestibular Stimulation (EVS) is a non-invasive technique for activating the vestibular-ocular reflex, evoking mainly a torsional eye movement response. We have previously demonstrated that this response can be used to detect vestibular asymmetry in patients with vestibular schwannoma (VS). Here we perform a direct comparison of EVS with caloric irrigation in this patient group. We studied 30 patients with unilateral VS, alongside an equal number of aged-matched healthy control subjects. EVS current was delivered to the mastoid process in a monaural configuration using a sinusoidal stimulus (2 Hz; ± 2 mA; 10 s), with an electrode placed over the spinous C7 process. Evoked eye movements were recorded from the right eye in darkness using an infra-red sensitive camera while the subject sat relaxed with their head on a chinrest. Ocular torsion was subsequently tracked off-line using iris striations. Each subject separately underwent water caloric irrigation, in accordance with the British Society of Audiology guidelines. For the caloric test, eye movement was recorded in the yaw axis using electro-oculography. For both EVS and calorics, inter-aural response asymmetry was calculated to determine the extent of canal paresis. Both tests revealed impaired vestibular function in the ipsilesional ear of VS patients, with a mean asymmetry ratio of 15 ± 17% and 18 ± 16% for EVS and calorics, respectively. Overall, the caloric test results discriminated controls from patients slightly more effectively than EVS (Cohen's D effect size = 1.44 vs. 1.19). Importantly, there was a significant moderate correlation between the AR values produced by EVS and calorics (r = 0.53, p < 0.01), and no significant difference between mean AR estimates. When questioned, ≥85% of participants subjectively preferred the EVS experience, in terms of comfort. Moreover, it took ~15 min to complete, vs. ~1 h for caloric. These results confirm that the results of the EVS test broadly agree with those of caloric irrigation, in terms of detecting vestibular asymmetry. Furthermore, they suggest a higher degree of convenience and patient comfort.

Ocular torsion responses to electrical vestibular stimulation in vestibular schwannoma.

OBJECTIVES: We determined if eye movements evoked by Electrical Vestibular Stimulation (EVS) can be used to detect vestibular dysfunction in patients with unilateral vestibular schwannoma (VS). METHODS: Ocular torsion responses to monaural sinusoidal EVS currents (±2 mA, 2 Hz) were measured in 25 patients with tumours ranging in size from Koos grade 1-3. For comparative purposes we also measured postural sway response to EVS, and additionally assessed vestibular function with the lateral Head Impulse Test (HIT). Patient responses were compared to age-matched healthy control subjects. RESULTS: Patients exhibited smaller ocular responses to ipsilesional versus contralesional EVS, and showed a larger asymmetry ratio (AR) than control subjects (19.4 vs. 3.3%, p < 0.05). EVS-evoked sway responses were also smaller in ipsilesional ear, but exhibited slightly more variability than the eye movement response, along with marginally lower discriminatory power (patients vs. controls: AR = 16.6 vs 2.6%, p < 0.05). The HIT test exhibited no significant difference between groups. CONCLUSIONS: These results demonstrate significant deficits in the ocular torsion response to EVS in VS patients. SIGNIFICANCE: The fast, convenient and non-invasive nature of the test are well suited to clinical use.

Pinna abscesses: can we manage them better? A case series and review of the literature.

Suppurative perichondritis of the pinna is a serious condition with potentially long-term cosmetic sequelae. Literature regarding the optimal treatment of these abscesses is scarce with most case series containing low numbers. This work reports the largest series from the UK to date; along with a review of recent literature. A 10-year retrospective review of case notes was undertaken. Demographic data, interventions and microbiology results were recorded along with outpatient descriptions of cosmetic outcomes. 20 patients were identified with male:female ratio of 4:1. Average patient age was 25.3 years (range 8-65). Average duration of symptoms prior to being seen by the ENT department was 9.95 days with an average length of stay in hospital of 2.5 days. 80% of patients had a surgical intervention performed. The commonest organism grown on microbiological culture was pseudomonas (33%). Of patients who attended follow-up, 28.6% had residual deformity. All of these had undergone surgical drainage of the abscess. Residual deformity was associated with longer time before presentation, piercing of the cartilage and a growth of pseudomonas. Prompt surgical management and appropriate antibiotic regimens to cover pseudomonas are the cornerstones of treatment in the event of pinna abscess formation.

Bilateral cochlear implantation after ethylene glycol intoxication: a case report.

OBJECTIVE: To report a case of deafness and blindness caused by ethylene glycol poisoning and treated by bilateral simultaneous cochlear implantation. STUDY DESIGN: Case report. SETTING: University teaching hospital, tertiary referral center. PATIENT: 37 years old man poisoned with ethylene glycol. INTERVENTION: Bilateral simultaneous Medel Sonata cochlear implants. OUTCOME MEASURE: BKB sentences (Bamford-Kowal-Bench sentence tests); AB words (Arthur Boothroyd monosyllabic words). RESULTS: Successful rehabilitation of hearing in a case of deafness and blindness of acute onset. CONCLUSION: Bilateral CI is an effective method of hearing rehabilitation in presence of additional disability (blindness).

Vestibular schwannoma management: current practice amongst UK otolaryngologists--time for a national prospective audit.

INTRODUCTION: It is generally agreed that the successful management of a vestibular schwannoma (VS) usually involves close collaboration between a neuro-otologist and neurosurgeon. In addition, it is accepted that the experience of the team managing such tumours is one of the key determinants of outcome after surgical intervention. The aim of this study was to identify current practice in the management of such tumours amongst otolaryngologists in the UK and to observe whether such collaborative working practices exist. MATERIALS AND METHODS: A cross sectional postal questionnaire survey of consultant members of the British Association of Otorhinolaryngologists-Head and Neck Surgeons (n = 542). RESULTS: A total of 336 replies were received (62%). Of respondents, 299 consultants referred their patients to another surgeon for further management; 242 referred to another ENT surgeon (80.9%), 29 to a neurosurgeon (9.7%) and 28 to a combined team (9.4%). Twenty-eight of the responding otolaryngologists (8.6%) managed the tumours themselves, of whom 22 worked with a neurosurgeon. Of these 28 neuro-otologists, nearly two-thirds (64%) had been undertaking VS surgery for more than 10 years. The total number of patients with a VS referred to these 28 consultants during 2001 was 775, with a mean caseload of 29.8, median 23 and a range of 4 to 102 per surgeon. Seven of the 28 otolaryngologists chose their surgical approach entirely based on the size of the tumour. Eight consultants preferred the sub-occipital (SO) approach, 10 the translabyrinthine (TL) approach, three chose between SO and TL approaches. The majority of surgeons had a prospective, computer-based data collection and were willing to give further information about their outcomes and complications. CONCLUSIONS: Amongst the otolaryngologists surveyed in the UK, we have identified 28 neuro-otologists who undertake VS surgery. The majority work with neurosurgical colleagues, confirming collaborative practice. The wide range in caseload raises the issue of training and maintaining standards and in the first instance we recommend a prospective national audit of VS management and outcomes with our neurosurgical colleagues. This would also be of value in manpower planning particularly if a minimum caseload could be identified below which results were seen to be less good.