Cian Hughes

The Use of Real-Time Image Stabilization and Augmented Reality Eyewear in the Treatment of Oscillopsia

Objectives/Hypothesis. The symptom of oscillopsia in patients with bilateral vestibular loss (BVL) can be reduced as dynamic visual acuity (DVA), the reduction in visual acuity during head movement, is improved by using real-time image stabilization, delivered by augmented reality eyewear. Setting. Tertiary multidisciplinary neurotology clinic. Study Design. Prospective experimental study. Methods. Immersive virtual reality glasses used in combination with a compact digital video camera were used. A software algorithm was developed that used a center-weighted Lucas-Kanade optical flow method to stabilize video in real time. Six patients with BVL were tested for changes in DVA using the eyewear. The ability to read a Snellen chart during a 2-Hz oscillating head rotation DVA test was measured. Results. For combined scores of vertical and horizontal head rotations, the mean number of lines readable at rest was 7.86, which dropped to 2.77 with head movement (a combination of vertical and horizontal perturbations). This increased to a mean of 6.14 lines with the image stabilization software being activated. This difference was statistically significant (P < .001). Conclusion. This is the first successful attempt to improve dynamic visual acuity in patients with bilateral vestibular loss. Recent hardware upgrades are promising in improving these results even further.

The behaviour of residual tumour after the intentional incomplete excision of a vestibular schwannoma: is it such a bad thing to leave some behind?

To evaluate the biological behaviour of tumour remnants intentionally left in the surgical bed following the incomplete excision of vestibular schwannomas (VS) and to review the relation between extent of resection and preservation of facial nerve function.

Providing auditory cues to improve stability in children who are deaf

INTRODUCTION Our ability to balance on two feet requires remarkable integration between multiple sensory systems and can be compromised when the available sensory information is discordant or insufficient. The traditional sensory inputs to balance include vision, proprioception, and vestibular end-organ function. Our recent experience in children with sensorineural hearing loss (SNHL) and cochlear implants (CI) has, however, led us to question the role that hearing, hearing loss, and CI have on balance. We have previously demonstrated that 50% of children with profound SNHL have an associated vestibular deficit and that early concerns about the negative impact of CI on vestibular function have not been substantiated. In general, children with SNHL can see with normal visual systems and feel with normal proprioceptors, but they have clear deficits in the hearing (cochlea) and at times the balance (vestibular) portions of their inner ears. How do these deficits alone or in combination impact balance function, and how can we rehabilitate these children?

Low-Cost Auditory Biofeedback for Bilateral Vestibular Loss

Objective: 1) Develop an auditory biofeedback device based on the Apple iPod Touch. 2) Investigate the efficacy of auditory biofeedback for patients with bilateral vestibular loss (BVL) using posturography. Method: The “Vestio” vestibular prosthesis provides auditory biofeedback via a small head-mounted device that can be housed in a cap. It uses inputs from the iPod’s onboard accelerometer and gyroscope to determine head movement. This generates auditory biofeedback using a combination of pure tone sounds and wide-band pulses. Results: Following a short training period, 5 patients with BVL were tested using the modified Clinical Test of Sensory Interaction on Balance (mCTSIB). Path length and COP were determined for each participant with Vestio turned off then repeated with the Vestio device turned on. These were compared using path length and sway. Both were found to be statistically significantly improved (P = .001). Repeat testing without the device showed a return to pre-test conditions. Patients in our pilot study went from falling on a hard surface with their eyes open to being stable on a compliant surface with their eyes closed. Conclusion: Auditory biofeedback can be successfully applied using this specialized software on a widely available, low-cost device. Further work is being undertaken to exploit real-time gait measurement to incorporate a walking version of the algorithm.

Digital Image Stabilization in the Treatment of Oscillopsia

Objective: 1) Develop real-time image stabilization using immersive augmented reality eyewear to counteract bobbing oscillopsia in patients with bilateral vestibular loss (BVL). 2) Measure change in dynamic visual acuity (DVA) in patients with BVL using the device. Method: Immersive virtual reality glasses used in combination with a compact digital video camera were used. A software algorithm was developed that used a center-weighted Lucas-Kanade optical flow method to stabilize video in real time. Six patients were tested for changes in DVA using the eyewear. Results: The ability to read a Snellen chart during a 2Hz oscillating head rotation DVA test showed a drop in visual acuity during head movement from a mean of 7.9 (SD = 0.8) lines at rest to 3.1 (SD = 2.0) lines during a 2Hz head rotation. This improved to 5.7 (SD = 1.2) lines with image stabilization with the same 2Hz rotation (P < .001). All reported a considerable subjective improvement in vision in addition to the Snellen chart test. Conclusion: This is the first successful attempt to improve dynamic visual acuity in patients with bilateral vestibular loss. Recent hardware upgrades are promising in improving these results even further.