Response characteristics of vestibular evoked myogenic potentials recorded over splenius capitis in young adults and adolescents.

BACKGROUND AND OBJECTIVES: Examine vestibular evoked myogenic potential (VEMP) responses recorded from surface electrodes over Splenius Capitis (SPC) in a seated position. SPECIFIC AIMS: (1) validate response characteristics of VEMP recordings from surface electrodes over Sternocleidomastoid (SCM) and over SCP and (2) assess age effects on responses in adolescents and young adults. MATERIALS AND METHODS: Simultaneous surface VEMP was recorded bilaterally from electrodes placed over the dorsal neck musculature at a location known from previous work to record from SPC in 15 healthy participants during trials with head rotation toward and away from the stimulated ear. VEMP was also recorded from electrodes over SCM, ipsilateral to the stimulus ear, in the same participants in a supine, head lift/turn position. RESULTS: Response amplitudes significantly increased with contraction strength and decreased with age. Participants were able to maintain sufficient contraction strength (amplitude) with head rotation to reliably measure over SPC. Normalized response amplitudes measured from electrodes over contralateral SPC were largest with head rotation contralateral to the stimulus ear. Normalized amplitudes and peak latencies were comparable to the same measures from SCM obtained in supine, head lift/turn position. CONCLUSIONS: Otolith generated myogenic responses can be recorded seated from electrodes over the dorsal neck with head rotation contralateral to the stimulus ear. In this position, contralateral recordings are consistent with responses known from previous work to arise from SPC; ipsilateral recordings may include crosstalk from activated muscles nearby, including ipsilateral SCM. Overall, techniques targeting contralateral SPC during contralateral head turn may provide additional methods of recording VEMPs.

Response characteristics of vestibular evoked myogenic potentials recorded over splenius capitis in young adults and adolescents

Background and objectives: Examine vestibular evoked myogenic potential (VEMP) responses recorded from surface electrodes over Splenius Capitis (SPC) in a seated position. Specific aims: (1) validate response characteristics of VEMP recordings from surface electrodes over Sternocleidomastoid (SCM) and over SCP and (2) assess age effects on responses in adolescents and young adults. Materials and methods: Simultaneous surface VEMP was recorded bilaterally from electrodes placed over the dorsal neck musculature at a location known from previous work to record from SPC in 15 healthy participants during trials with head rotation toward and away from the stimulated ear. VEMP was also recorded from electrodes over SCM, ipsilateral to the stimulus ear, in the same participants in a supine, head lift/turn position. Results: Response amplitudes significantly increased with contraction strength and decreased with age. Participants were able to maintain sufficient contraction strength (amplitude) with head rotation to reliably measure over SPC. Normalized response amplitudes measured from electrodes over contralateral SPC were largest with head rotation contralateral to the stimulus ear. Normalized amplitudes and peak latencies were comparable to the same measures from SCM obtained in supine, head lift/turn position. Conclusions: Otolith generated myogenic responses can be recorded seated from electrodes over the dorsal neck with head rotation contralateral to the stimulus ear. In this position, contralateral recordings are consistent with responses known from previous work to arise from SPC; ipsilateral recordings may include crosstalk from activated muscles nearby, including ipsilateral SCM. Overall, techniques targeting contralateral SPC during contralateral head turn may provide additional methods of recording VEMPs.(AU)

Antecedentes y objetivos: Examinamos las respuestas de los potenciales evocados miogénicos vestibulares (PEMV) recogidas de los electrodos de superficie sobre el músculo esplenio (ME) en posición sentada. Objetivos específicos: 1) validar las características de los registros de la respuesta de los PEMV recogidos de los electrodos de superficie sobre el músculo esternocleidomastoideo (SCM) y el ME, y 2) evaluar los efectos de la edad en adolescentes y adultos jóvenes. Materiales y métodos: Se registraron simultáneamente los PEMV bilaterales de los electrodos situados en la musculatura dorsal del cuello, en un sitio conocido de un estudio anterior para obtener registros del ME en 15 participantes sanos durante los ensayos, con rotación de cabeza hacia y fuera del oído estimulado. También se registraron los PEMV de los electrodos situados sobre el SCM, en posición ipsilateral al oído estimulado, en los mismos participantes, en posición supina y con elevación/giro de cabeza. Resultados: Las amplitudes de la respuesta se incrementaron significativamente con la fuerza de la contracción y disminuyeron con la edad. Los participantes fueron capaces de mantener suficiente fuerza de contracción (amplitud) con la rotación de cabeza, para realizar mediciones fiables sobre el ME. Las amplitudes de la respuesta normalizada medidas en los electrodos sobre el ME contralateral fueron mayores con la rotación de cabeza contralateral al oído estimulado. Las amplitudes normalizadas y las latencias máximas fueron comparables a las mismas medidas del SCM obtenidas en posición supina, y elevación/giro de cabeza. Conclusiones: Las respuestas miogénicas generadas por otolitos pueden registrarse en posición sentada a partir de los electrodos situados en la parte dorsal del cuello, contralateral al oído estimulado. En esta posición, los registros contralaterales son coherentes con las respuestas conocidas de un estudio previo, derivadas del ME; los registros ipsilaterales pueden incluir interferencias de los músculos activados cercanos, incluyendo el SCM ipsilateral. En general, las técnicas centradas en el ME contralateral durante el giro de cabeza contralateral pueden aportar métodos adicionales de registro de los PEMV.(AU)

Response characteristics of vestibular evoked myogenic potentials recorded over splenius capitis in young adults and adolescents.

BACKGROUND AND OBJECTIVES: Examine vestibular evoked myogenic potential (VEMP) responses recorded from surface electrodes over Splenius Capitis (SPC) in a seated position. SPECIFIC AIMS: (1) validate response characteristics of VEMP recordings from surface electrodes over Sternocleidomastoid (SCM) and over SCP and (2) assess age effects on responses in adolescents and young adults. MATERIALS AND METHODS: Simultaneous surface VEMP was recorded bilaterally from electrodes placed over the dorsal neck musculature at a location known from previous work to record from SPC in 15 healthy participants during trials with head rotation toward and away from the stimulated ear. VEMP was also recorded from electrodes over SCM, ipsilateral to the stimulus ear, in the same participants in a supine, head lift/turn position. RESULTS: Response amplitudes significantly increased with contraction strength and decreased with age. Participants were able to maintain sufficient contraction strength (amplitude) with head rotation to reliably measure over SPC. Normalized response amplitudes measured from electrodes over contralateral SPC were largest with head rotation contralateral to the stimulus ear. Normalized amplitudes and peak latencies were comparable to the same measures from SCM obtained in supine, head lift/turn position. CONCLUSIONS: Otolith generated myogenic responses can be recorded seated from electrodes over the dorsal neck with head rotation contralateral to the stimulus ear. In this position, contralateral recordings are consistent with responses known from previous work to arise from SPC; ipsilateral recordings may include crosstalk from activated muscles nearby, including ipsilateral SCM. Overall, techniques targeting contralateral SPC during contralateral head turn may provide additional methods of recording VEMPs.

Vestibular evoked myogenic potential testing as an objective measure of vestibular stimulation with cochlear implants.

OBJECTIVES/HYPOTHESIS: To determine if vestibular potentials could be elicited with electrical stimulation from cochlear implants. STUDY DESIGN: Prospective cohort study. METHODS: Vestibular responsiveness to electrical stimulation from cochlear implants was assessed via vestibular evoked myogenic potential (VEMP) testing in 53 pediatric and young adult patients. RESULTS: Thirty-one participants (58%) showed at least one vestibular potential in response to acoustic stimulation; 33 (62%) had an electrically evoked vestibular response. A cervical VEMP (cVEMP) was present in 45 of the 96 tested ears (47%) in response to acoustic stimulation, and in 34 ears (35%) with electrical stimulation. An ocular VEMP (oVEMP) was elicited acoustically in 25 ears (26%) and electrically in 34 (35%) ears. In the ears with absent responses to acoustic stimuli, electrically evoked cVEMPs and oVEMPs were present in 14 (27%) and 18 (25%) ears, respectively. Electric VEMPs demonstrated shorter latencies than acoustic VEMPs (P < .01). Whereas an increased prevalence of VEMPs was seen at high stimulation levels (P < .01), there was no difference between prevalence proportions with basal (electrode 3) or apical (electrode 20) stimulation (P > .05). CONCLUSIONS: VEMPs can be elicited with electrical stimulation in a proportion of children with cochlear implants, demonstrating current spread from the cochlea to the vestibular system. The presence of electric VEMPs in acoustically nonresponsive ears, along with the shorter latencies of electrically driven VEMPs, suggests that electrical current can bypass the otoliths and directly stimulate vestibular neural elements. LEVEL OF EVIDENCE: 4. Laryngoscope, 2016 127:E75-E81, 2017.

Stimulation from Cochlear Implant Electrodes Assists with Recovery from Asymmetric Perceptual Tilt: Evidence from the Subjective Visual Vertical Test.

Vestibular end organ impairment is highly prevalent in children who have sensorineural hearing loss (SNHL) rehabilitated with cochlear implants (CIs). As a result, spatial perception is likely to be impacted in this population. Of particular interest is the perception of visual vertical because it reflects a perceptual tilt in the roll axis and is sensitive to an imbalance in otolith function. The objectives of the present study were thus to identify abnormalities in perception of the vertical plane in children with SNHL and determine whether such abnormalities could be resolved with stimulation from the CI. Participants included 53 children (15.2 ± 4.0 years of age) with SNHL and vestibular loss, confirmed with vestibular evoked myogenic potential (VEMP) testing. Testing protocol was validated in a sample of nine young adults with normal hearing (28.8 ± 7.7 years). Perception of visual vertical was assessed using the static Subjective Visual Vertical (SVV) test performed with and without stimulation in the participants with cochleovestibular loss. Trains of electrical pulses were delivered by an electrode in the left and/or right ear. Asymmetric spatial orientation deficits were found in nearly half of the participants with CIs (24/53 [45%]). The abnormal perception in this cohort was exacerbated by visual tilts in the direction of their deficit. Electric pulse trains delivered using the CI shifted this abnormal perception towards center (i.e., normal; p = 0.007). Importantly, this benefit was realized regardless of which ear was stimulated. These results suggest a role for CI stimulation beyond the auditory system, in particular, for improving vestibular/balance function.

Exploring the psychological morbidity of waiting for sinus surgery using a mixed methods approach.

BACKGROUND: Patients with chronic rhinosinusitis (CRS) often have to endure significant wait times for endoscopic sinus surgery (ESS). The pyschiatric impact of placement on a waitlist for ESS has not been explored. METHODS: Questionnaires measuring CRS symptom severity and health-related anxiety and stress (SNOT-22, HADS, WPAI-GH) were sent to patients diagnosed with CRS and currently on a waitlist for ESS. Fifteen representative waitlisted patients participated in one-on-one semi-structured interviews discussing their experience with their wait for ESS. A deductive thematic analysis was used to interpret the interview data using a quantitative driven mixed methods analysis. RESULTS: Participants waiting for ESS reported worsening clinical symptomatology during their waiting period. Participants reported waitlist and CRS impact on both work and social aspects of their lives. The HADS scale showed no overall significant level of depression or anxiety in the HADS screening questionnaire. The qualitative data describe the effects of the symptom burden of CRS. CONCLUSIONS: Patients waitlisted for ESS did not demonstrate any significant level of psychiatric distress, however variability exists. The qualitative arm of this study elucidates how patients cope with their wait.

Absorbable Steroid-Impregnated Spacer After Endoscopic Sinus Surgery to Reduce Synechiae Formation.

OBJECTIVE: Middle meatal synechiae formation after endoscopic sinus surgery (ESS) for chronic rhinosinusitis (CRS) leads to higher rates of revision surgery. We aimed to determine if there are different rates of postoperative synechiae following ESS for CRS between patients who received a nonabsorbable spacer (NAS) placed in the ethmoid cavity versus patients who had a steroid-impregnated absorbable spacer (AS) placed at the middle meatal entry. METHODS: We conducted a retrospective cohort study of patients who underwent ESS for CRS at a single tertiary referral center from October 2009 to October 2013. We collected data on synechiae formation between the middle turbinate and lateral nasal wall within 1 month of surgery and postoperative epistaxis. RESULTS: One hundred forty-six patients with 252 nasal cavities (52.0%) received steroid-impregnated AS, and 128 patients with 233 nasal cavities (48.0%) received NAS. Synechiae formation occurred in 2.0% of cavities with AS and 5.6% of cavities with NAS, but this difference was not statistically significant (OR = 0.34, P = .052). One patient in each cohort had significant postoperative epistaxis requiring additional nasal packing (P > .99). CONCLUSION: Steroid-impregnated absorbable spacers had statistically insignificant reduction in postoperative synechiae formation when compared to nonabsorbable spacers. Low rates of postoperative epistaxis were observed regardless of the type of spacer used.

Nasal nitric oxide as a marker of sinus mucosal health in patients with nasal polyposis.

BACKGROUND: Reduced nasal nitric oxide (nNO) has been shown in patients with chronic rhinosinusitis (CRS) but its clinical significance remains uncertain. The objective of this study was to measure nNO changes in patients undergoing endoscopic sinus surgery (ESS) for CRS and to explore its relationship to clinical measures of sinus mucosal health postoperatively. METHODS: This was a prospective study of CRS patients undergoing ESS. Patients had the following measurements at baseline and at 1 and 6 months post-ESS: nNO levels, Lund-Kennedy Endoscopy Score (LKES), and 22-item Sino-Nasal Outcome Test (SNOT-22) score. Statistical analysis was performed using GraphPad Prism 6. RESULTS: Thirty-nine patients were enrolled, of these 84.6% had CRS with nasal polyps. Baseline Lund-Mackay computed tomography (CT) score was 16.9 ± 5.1. There was a statistically significant increase in nNO levels from baseline to 1 month and 6 months postoperatively (p < 0.0001). The SNOT-22 and LKES followed a similar trend with a significant and sustained improvement at 1 month and 6 months post-ESS (p < 0.0001). Subgroup analysis revealed that changes in nNO were driven by the polyp cohort because nonpolyp patients had no significant changes in their nNO postoperatively. No correlation was found between nNO levels and SNOT-22. However, a significant negative correlation was found between nNO and LKES (p < 0.0001), suggesting healthier sinus mucosa was associated with higher nNO levels. CONCLUSION: This is the first study to show that nNO levels may be a marker of sinus mucosal health following ESS in patients with polyps. This has important implications for nNO in its potential etiologic role in mediating ongoing sinus inflammation.

Direct measurement of the wavelength of sound waves in the human skull.

The results of a study of the three-dimensional vibration of two dry human skulls in response to harmonic excitation are presented. The vibratory response exhibits three distinct types of motion across the range of audible frequencies. At low frequencies below 1000 Hz, whole-head quasi-rigid motion is seen. At the middle frequencies between 1000 and 6000 Hz, the motion exhibits a series of increasingly complex modal patterns. Above 6000 Hz, the response is wavelike and clear wavefronts can be distinguished in the vibration data. In this regime the relationship between wavelength and frequency is calculated and compared to a number of theories of skull vibration that have been proposed.