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)

Age-related changes to vestibular heave and pitch perception and associations with postural control.

Falls are a common cause of injury in older adults (OAs), and age-related declines across the sensory systems are associated with increased falls risk. The vestibular system is particularly important for maintaining balance and supporting safe mobility, and aging has been associated with declines in vestibular end-organ functioning. However, few studies have examined potential age-related differences in vestibular perceptual sensitivities or their association with postural stability. Here we used an adaptive-staircase procedure to measure detection and discrimination thresholds in 19 healthy OAs and 18 healthy younger adults (YAs), by presenting participants with passive heave (linear up-and-down translations) and pitch (forward-backward tilt rotations) movements on a motion-platform in the dark. We also examined participants' postural stability under various standing-balance conditions. Associations among these postural measures and vestibular perceptual thresholds were further examined. Ultimately, OAs showed larger heave and pitch detection thresholds compared to YAs, and larger perceptual thresholds were associated with greater postural sway, but only in OAs. Overall, these results suggest that vestibular perceptual sensitivity declines with older age and that such declines are associated with poorer postural stability. Future studies could consider the potential applicability of these results in the development of screening tools for falls prevention in OAs.

Vestibular Perceptual Thresholds in Older Adults With and Without Age-related Hearing Loss.

OBJECTIVES: Older adults with age-related hearing loss (ARHL) are at greater risk of falling and have greater mobility problems than older adults with normal hearing (NH). The underlying cause of these associations remains unclear. One possible reason is that age-related declines in the vestibular system could parallel those observed in the auditory system within the same individuals. Here, we compare the sensitivity of vestibular perceptual abilities (psychophysics), vestibular end-organ functioning (vestibular evoked myogenic potentials and video head impulse tests), and standing balance (posturography) in healthy older adults with and without ARHL. DESIGN: A total of 46 community-dwelling older adults, 23 with ARHL and 23 with NH, were passively translated in heave (up and down) and rotated in pitch (tilted forward and backward) in the dark using a motion platform. Using an adaptive staircase psychophysical procedure, participants' heave and pitch detection and discrimination thresholds were determined. In a posturography task, participants' center of pressure (COP) path length was measured as they stood on a forceplate with eyes open and closed, on firm and compliant surfaces, with and without sound suppression. Baseline motor, cognitive, and sensory functioning, including vestibular end-organ function, were measured. RESULTS: Individuals with ARHL were less sensitive at discriminating pitch movements compared to older adults with NH. Poorer self-reported hearing abilities were also associated with poorer pitch discrimination. In addition to pitch discrimination thresholds, lower pitch detection thresholds were significantly associated with hearing loss in the low-frequency range. Less stable standing balance was significantly associated with poorer vestibular perceptual sensitivity. DISCUSSION: These findings provide evidence for an association between ARHL and reduced vestibular perceptual sensitivity.

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.

Evaluating the effectiveness of learning ear anatomy using holographic models.

BACKGROUND: Computer-assisted learning has been shown to be an effective means of teaching anatomy, with 3-D visualization technology more successfully improving participants' factual and spatial knowledge in comparison to traditional methods. To date, however, the effectiveness of teaching ear anatomy using 3-D holographic technology has not been studied. The present study aimed to evaluate the feasibility and effectiveness of learning ear anatomy using a holographic (HG) anatomic model in comparison to didactic lecture (DL) and a computer module (CM). METHODS: A 3-D anatomic model of the middle and inner ear was created and displayed using presentation slides in a lecture, computer module, or via the Microsoft HoloLens. Twenty-nine medical students were randomized to one of the three interventions. All participants underwent assessment of baseline knowledge of ear anatomy. Immediately following each intervention, testing was repeated along with completion of a satisfaction survey. RESULTS: Baseline test scores did not differ across intervention groups. All groups showed an improvement in anatomic knowledge post-intervention (p < 0.001); the improvement was equal across all interventions (p = 0.06). Participants rated the interventions equally for delivery of factual content (p = 0.96), but rated the HG higher than the DL and CM for overall effectiveness, ability to convey spatial relationships, and for learner engagement and motivation (p < 0.001). CONCLUSIONS: These results suggest that 3-D holographic technology is an effective method of teaching ear anatomy as compared to DLs and CMs. Furthermore, it is better at engaging and motivating learners compared to traditional methods, meriting its inclusion as a tool in undergraduate medical education curriculum.

Preliminary experience using a cochlear implant with a novel linear pedestal design.

OBJECTIVE: To assess the safety and efficiency of cochlear implantation using a novel device with a linear silastic pedestal (2 mm wide, 2 mm deep, 10 mm long) on the flat undersurface. METHODS: Operative times required to drill a linear groove (LG) for the new linear pedestal design were prospectively accrued for 46 implantations in 30 children (median age 3). Intra-operative safety was assessed during each case. Instances of dural exposure in the base of the LG were noted. Length of stay was also recorded as a secondary measure of efficiency. RESULTS: Across all surgeons, the mean time needed to create the LG was 1.9 ± 1.5 min (±SD) with a median time of 1.5 min (95% Cl: 1-2 min). The range in time was 1-10 min. No intraoperative complications occurred. Intended device positioning was confirmed with on-table post-operative x-rays in all cases. 43% of patients were discharged on the day of surgery. CONCLUSIONS: The novel linear pedestal design allows for deliberate device placement while adding little additional operative time and complexity, an improvement on our current standard of care.

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.

Perioperative nonselective non-steroidal anti-inflammatory drugs are not associated with anastomotic leakage after colorectal surgery.

INTRODUCTION: Recent evidence raises concern about the use of perioperative non-steroidal anti-inflammatory drug (NSAID) use after colorectal resection. The purpose of this retrospective cohort study was to investigate the relationship between perioperative ketorolac use and anastomotic leakage after colorectal surgery. METHODS: A retrospective review (2004-2011) was performed on patients who underwent elective colorectal surgery. Univariate analysis and multivariate logistic regression were used to evaluate the association between patients who did not receive any NSAIDs and those who received ketorolac within the first 5 days perioperatively and leak rate. RESULTS: A total of 731 patients were identified as having resection with primary anastomosis: 376 (51.4 %) received no NSAIDs and 355 (48.6 %) received ketorolac perioperatively within 5 days after their surgery. There were 24 (3.3 %) leaks, with 12 in both the no NSAIDs (3.2 %) and ketorolac (3.4 %) groups, odds ratio (OR) 1.06 (0.43, 2.62; p = 0.886). Adjusting for smoking, steroid use, and age, there remained no significant difference between ketorolac use and leakage, OR 1.21 (0.52, 2.84; p = 0.660). In our multivariate model, only smoking was a significant predictor of postoperative leak, OR 3.34 (1.30, 8.62; p = 0.021). CONCLUSIONS: There does not appear to be a significant association between perioperative ketorolac use and anastomotic leakage after colorectal surgery. However, further prospective studies are needed to confirm our findings before definitive guidelines on NSAID use perioperatively can be recommended.