Suwicha Isaradisaikul

Reliability of Vestibular Evoked Myogenic Potentials in Healthy Subjects

Objective: To analyze test-retest reliability of vestibular evoked myogenic potential (VEMP) responses with and without the use of electromyography (EMG) monitoring in people with normal audiovestibular function. Patients: Twenty adult volunteers with no history of ear disease, normal otoscopic examination, normal pure-tone audiometry thresholds, and normal tympanograms. Interventions: Prospective evaluation of VEMP responses with and without the use of EMG monitoring in 2 separate sessions 1 to 4 weeks apart. Main Outcome Measures: Threshold repeatability, p13 and n23 latency, p13-n23 interlatency, and interamplitude and interaural amplitude difference from the first and the second sessions were assessed via the intraclass correlation coefficient. Results: Test-retest reliability of p13-n23 interamplitude was found to be excellent, and the reliability of threshold and latency was found to be fair to good (with the exception of poor reliability for p13 latency in the EMG monitoring condition). Conclusion: Overall, VEMP response parameters were found to have fair to good test-retest reliability. The intraclass correlation coefficient value for amplitude was found to be more reliable than latency, with the latency of n23 more reliable than the latency of p13. Clinicians should consider these findings when interpreting VEMP responses. Maintenance of symmetric head rotation with and without EMG monitoring produced reliably reproducible results, the VEMP amplitude being the best criteria.

Cervical Vestibular-Evoked Myogenic Potentials: Norms and Protocols

Vestibular-evoked myogenic potential (VEMP) testing is a vestibular function test used for evaluating saccular and inferior vestibular nerve function. Parameters of VEMP testing include VEMP threshold, latencies of p1 and n1, and p1-n1 interamplitude. Less commonly used parameters were p1-n1 interlatency, interaural difference of p1 and n1 latency, and interaural amplitude difference (IAD) ratio. This paper recommends using air-conducted 500 Hz tone burst auditory stimulation presented monoaurally via an inserted ear phone while the subject is turning his head to the contralateral side in the sitting position and recording the responses from the ipsilateral sternocleidomastoid muscle. Normative values of VEMP responses in 50 normal audiovestibular volunteers were presented. VEMP testing protocols and normative values in other literature were reviewed and compared. The study is beneficial to clinicians as a reference guide to set up VEMP testing and interpretation of the VEMP responses.

Surgical Site Infections in Ear Surgery Hair Removal Effect; a Preliminary, Randomized Trial Study

Objective (1) To compare the rate of surgical site infections in ear surgery between groups with and without hair removal and (2) to study factors associated with surgical site infections. Study Design A preliminary, randomized, controlled trial. Setting University hospital. Subjects and Methods The study was conducted in a group of 136 patients who underwent surgery for external or middle ear disease via the post-auricular approach at Chiang Mai University Hospital from May 2010 to May 2011. Demographic data, surgical site infection within 30 days postoperatively, and associated factors were recorded. Results Fifty-eight cases were men and 78 cases women. Demographic data between the 2 groups were compared. Age, gender, the side of operated ear, types of anesthesia, emergency or elective setting, body mass index, history of alcohol and/or tobacco use, underlying diseases, operative time, and the length of hospital stay revealed no significant differences. A postoperative surgical site infection developed in 5 patients: 3 in the group with hair removal (4.5%) and 2 in the group without hair removal (2.8%) (P value = 0.674, Fisher’s exact test). All infected cases had undergone mastoidectomy. Conclusions Surgical site infection rates between the 2 groups (with and without hair removal) demonstrated no difference. Hair removal prior to ear surgery via post-auricular incision had no effect on the rate of surgical site infection.

Role of cervical vestibular evoked myogenic potential response in identifying vestibular dysfunction.

OBJECTIVES To analyse cervical vestibular evoked myogenic potential response parameters in normal volunteers and vertiginous patients. SUBJECTS AND METHODS A prospective study of 50 normal subjects and 50 patients with vertigo was conducted at Chiang Mai University Hospital, Thailand. Cervical vestibular evoked myogenic potential responses were measured using air-conducted, 500-Hz, tone-burst stimuli with subjects in a sitting position with their head turned toward the contralateral shoulder. RESULTS The mean ± standard deviation age and male:female ratio in the normal (44.0 ± 9.3 years; 12:38) and vertigo groups (44.7 ± 9.8 years; 17:33) were not significantly different. The prevalence of absent responses in the normal (14 per cent) and vertigo ears (46 per cent) differed significantly (p < 0.0001). Other cervical vestibular evoked myogenic potential parameters (i.e. response threshold, P1 and N1 latency, P1–N1 interlatency and interamplitude, inter-ear difference in P1 threshold, and asymmetry ratio) showed no inter-group differences. CONCLUSION The absence of a cervical vestibular evoked myogenic potential response is useful in the identification of vestibular dysfunction. However, patients should undergo a comprehensive battery of other vestibular tests to supplement their cervical vestibular evoked myogenic potential response findings.

Cervical VEMP: Its Sensitivity and Specificity

Objective: 1) Analyze the sensitivity and specificity of cervical vestibular evoked myogenic potential (VEMP) in evaluation vestibular function. 2) Compare the cervical VEMP response in normal volunteers and vertiginous patients. Method: A prospective study in 50 normal subjects and 50 vertigo patients was conducted at Chiang Mai University Hospital from February to December 2009. Cervical VEMP responses using air-conducted 500-Hz tone-burst stimuli with the subjects in a sitting position and head turned to contralateral shoulder were analyzed. Results: Average age and men-to-women ratio in the normal group (44.0 ± 9.3 years; 12:38) and in the vertigo group (44.7 ± 9.8 years; 17:33) were not different. The rate of absent response between normal ears (15%) and disease ears (47.4%) showed a significant difference (p value < 0.0001). Conclusion: To identify vestibular dysfunction using cervical VEMP, the absence of response was the most diagnostic parameter. Other vestibular test batteries should be added to confirm the cervical VEMP responses.

R081: VEMP Absence, Caloric Weakness, and Hearing Loss

based on the major and minor critera described by the 1997 Task Force in Rhinology (TFR). This study attempts to discriminate among the various criteria to identify individual symptom predictors of CRS as well as to evaluate the predictive accuracy of the TFR criteria in aggregate. METHODS: A retrospective chart review of 187 patients referred to a tertiary care rhinology clinic for evaluation of suspected chronic rhinosinusitis. Data reviewed included each patient’s symptoms, as recorded in a standarized survey that included all of the major and minor criteria and each patient’s diagnosis (CRS or other). RESULTS: Of 187 patients who met inclusion criteria, 112 (60%) were diagnosed with CRS and 75 (40%) were diagnosed with conditions other than CRS. Chronic purulent rhinorrhea and hyposmia individually and in combination were significant predictors of CRS [odds ratio (OR) 2.2, 2.3, and 3.8, respectively]. The major criteria (facial pain, congestion, nasal obstruction, nasal discharge, and hyposmia) also predicted CRS (OR 1.9) but the minor criteria (headache, fever, halitosis, fatigue, dental pain, cough, ear pain) did not predict CRS (OR 0.3). CONCLUSION: The major criteria of the 1997 TFR predict CRS but the minor criteria do not. Refinement of the symptomatic criteria for the diagnosis of suspected CRS may improve the accuracy of a clinical diagnosis of CRS. SIGNIFICANCE: This study identifies hyposmia and purulent rhinorrhea as independent predictors of CRS and confirms the predictive value of the major criteria. However, it also suggests that symptoms considered minor factors by the AAO-HNS TFR are not predictive of CRS.