Effects of anesthesia on efferent-mediated adaptation of the DPOAE.

Distortion product otoacoustic emissions (DPOAE) adapt after primary tone onset, with an approximately 100 ms time constant, due to feedback effects of medial olivocochlear (MOC) activity elicited by the primary tones. We tracked DPOAE postonset adaptation as a metric of MOC reflex strength, before during and after induction of anesthesia in guinea pigs. Reflex strength was significantly diminished by the barbiturate/neuroleptic anesthesia most commonly used in this species. The MOC reflex recovered more slowly than toe-pinch or startle reflexes, correlating better with recovery of general mobility. When individual anesthetic agents were assessed, the barbiturate (pentobarbital) significantly diminished MOC reflex strength, whereas fentanyl or droperidol did not. These results suggest that previous studies using anesthetized preparations may have underestimated the magnitude of sound-evoked responses in the OC pathway.

Validation of a patient-graded instrument for facial nerve paralysis: the FaCE scale.

OBJECTIVE: To develop and validate a patient-based instrument to measure both facial impairment and disability, the Facial Clinimetric Evaluation (FaCE) Scale. STUDY DESIGN: Prospective instrument validation. METHODS: Eighty-six patients with a documented history of facial paralysis completed a preliminary, 51-item instrument (alpha FaCE Scale), as well as the previously developed Facial Disability Index (FDI) and the Medical Outcomes Study Short Form 36 Item Questionnaire (SF-36). Two weeks after completing these instruments, 76 patients again completed the alpha FaCE Scale. Forty-one of the patients were also evaluated using the House-Brackmann Grading System (HBGS) and the Facial Grading System (FGS). RESULTS: Exploratory principal component factor analysis grouped 15 FaCE Scale items into 6 impairment and disability categories (domains), forming the beta FaCE Scale. Overall, the test-retest reliability of the FaCE Scale was high (Spearman's correlation coefficient (r) = 0.88, P <.01), as were the reliability coefficients of the individual domains (r = 0.81-0.92, P <.01). The FaCE Scale domains showed appropriate correlation to global visual analogue scale questions posed on the original alpha FaCE Scale (r = 0.65-0.81, P <.01). Overall, the FaCE Scale showed significant correlation with HBGS and FGS scores (r = -0.55 and 0.57, respectively; P <.01). However, not all FaCE Scale domains correlated with the HBGS and FGS scores. CONCLUSIONS: A reliable and valid patient-based system to measure impairment and disability in facial paralysis has been developed. This system appears to be better than traditional, physician-graded scales for evaluating quality-of-life issues affected by facial disability.

Success of the modified Epley maneuver in treating benign paroxysmal positional vertigo.

OBJECTIVE: Benign paroxysmal positional vertigo (BPPV) is a common condition seen by otolaryngologists. The purpose of this study is to determine the ability of the modified Epley maneuver to treat BPPV. STUDY DESIGN: Retrospective review. METHODS: A retrospective chart review of 107 patients diagnosed with BPPV at our institution between March of 1993 and June of 1995. Each patient was diagnosed with isolated BPPV by history and Hallpike-Dix maneuver. There were no other vestibular symptoms or electronystagmogram abnormalities. Patients diagnosed with BPPV received modified Epley maneuvers, were instructed to remain upright for 48 hours, and wore a soft collar for a week. Patients were followed up with repeat Hallpike-Dix maneuvers at 1 to 2 weeks. If symptoms persisted, the maneuver was repeated for up to a maximum of three times, at which point patients were considered to have failed treatment. RESULTS: The average age of patients was 57.8 years old. Thirty percent were male and the right ear was affected in 54%. The posterior semicircular canal was affected in 105 ears. The average patient received 1.23 Epley maneuvers, with a success rate of 93.4%. No successfully treated patients received mastoid vibration. Seven out of 107 patients failed after three Epley maneuvers. Two failure patients had a history of temporal bone fracture. Two failure patients were treated with posterior semicircular canal block surgery. CONCLUSION: The modified Epley maneuver is an excellent treatment for BPPV.