Comparison of ocular vestibular myogenic response by acoustic stimulation at 500 and 1000 Hz in healthy subjects.

OBJECTIVE: To compare the amplitude of potentials by acoustic stimulation at 500 Hz versus 1000 Hz in healthy subjects. METHODS: 25 subjects; potentials were performed with acoustic stimuli burst-type at 500 and 1000 Hz with a stimulation rate of 5.1 at 100 dB in both ears. Descriptive statistics tests were performed, confidence intervals were calculated for the mean with 95% reliability, standard error graphs and t-test for related samples. RESULTS: The values obtained in amplitude when performing an acoustic stimulus at 1000 Hz show a faster response compared to that obtained in the frequency of 500 Hz. The t-test showed a significant difference in the amplitude in the 1000 Hz frequency between ears with a significance value of p < 0.025. CONCLUSIONS: It is strengthened the hypothesis that in the amplitude of potentials by aerial acoustic stimulation in the frequency of 1000 Hz a greater amplitude is generated in relation to the one generated in the frequency of 500 Hz.

OBJETIVO: Comparar la amplitud de los potenciales miogénicos vestibulooculares por estimulación acústica a 500 y 1000 Hz en sujetos sanos. MÉTODO: Se estudiaron 25 sujetos y se realizaron potenciales con estímulos acústicos tipo burst a 500 y 1000 Hz con una tasa de estimulación de 5.1 a 100 dB en ambos oídos. Se realizaron pruebas de estadística descriptiva y se calcularon los intervalos de confianza para la media con un 95% de confiabilidad, las gráficas de error estándar y la prueba t para muestras relacionadas. RESULTADOS: Los valores obtenidos en amplitud al realizar estímulo acústico a 1000 Hz muestran una respuesta más rápida en comparación con la obtenida en la frecuencia de 500 Hz. La prueba t mostró una diferencia significativa en la amplitud en la frecuencia 1000 Hz entre oídos, con un valor de significancia p < 0.025. CONCLUSIONES: Se fortalece la hipótesis de que en los potenciales por estimulación acústica aérea en la frecuencia de 1000 Hz se genera una mayor amplitud en relación con la generada en la frecuencia de 500 Hz.

Audiometric evaluation short and medium term in cochlear implants.

OBJECTIVE: Our purpose is report the results of cochlear implant program in this Institute, since our first surgery from November 2007, until December 2012. MATERIAL AND METHODS: A cross-sectional study, observational, descriptive, analyzing the information about thresholds before and after implantation, using patients files (diagnosis, onset of hearing loss, brainstem auditory evoked potential (BAEP), computed tomography (CT), magnetic resonance imaging (MRI), implanted ear, brand and model of cochlear implants (CI) and audiometric studies before and after the CI. RESULTS: We report the evolution of 68 patients, age ranged 1 year 8 months to 39 years 3 months old. 94% patients (n = 64) had pre-lingual hearing loss being hereditary non-syndromic hearing loss the most common etiology (29.4%). 100% patients had auditory brainstem responses showing bilateral profound hearing loss, in the 77.9% type A tympanograms were obtained (Jerger's classification), and 100% had absence of stapedial reflexes and otoacoustic emissions with low reproducibility. CT reported as normal in 85.2% of patients, the findings: 5.8% had chronic mastoiditis changes, other findings reported in 1.4% of patients were: digastric right facial nerve, facial nerve canal dehiscence, enlarged vestibular aqueduct, occupation and poor pneumatization of mastoid air cells, lateral semicircular canals agenesis, incomplete partition of the cochlea with wide vestibular and vestibular aqueduct dilatation. Most frequent MR findings of skull with cerebellopontine angle approach were vascular loops of internal auditory canals unilaterally. In 10.2%, 55.8% of patients (n = 38) were implanted in the right ear, 56 (82.3%) with a CI from Advanced Bionics, HiRes 90K model, the remaining with Cochlear, Freedom and Nucleus 5 models. Developments in CI results by audiometric tests: prior to placement was 106.2 dB averages at frequencies assessed, one month later 62.4 dB, at 6 months 44 dB, and with satisfactory threshold 32.9 dB. 55.8% of patients (n = 38) with P + HiRes Fidelity 120 strategy, the remaining with Hires S + Fidelity 120, Hires S and ACE RE. DISCUSSION: Audiology service proposed to place the CI in the worst ear by threshold in audiometric tests, the otolaryngology service proposed the best ear from anatomical point view. Implanted in the INR more Advanced Bionics CI faq frequently due to the donation by the insurance for a new generation. Hearing thresholds using CI have improved since activation.