Search Results (4)

Reliable acoustic coupling in a non-handheld mode and reducing the form factor of electronics are specific challenges in making ultrasound wearable. Applications relying on a large field of view (such as tracking of large muscles) induce a need for a large element count to achieve high image quality. In our work, we developed a 256-element linear array for imaging of abdominal muscles with four integrated custom-developed 8:32 multiplexer Integrated Circuits (ICs), allowing the array to be driven by our compact 32 ch electronics. The system is optimized for flexible use in R&D applications and allows adjustable transmit voltages (up to +/−100 V), arbitrary delay patterns, and 12-bit analog-to-digital conversion (ADC) with up to 50 MSPS and wireless (21.6 MBit/s) or USB link. Image metrics (SLL, FWHM) were very similar to a fully populated array driven with a 256 ch system. The contrast allowed imaging of lesions down to 7 cm in the phantom. In a first in-vivo study, we demonstrated reliable acoustic contact even during exercise and were able to visualize deep abdominal muscles such as the TrA. In combination with a muscle tracking algorithm, the change of thickness of the TrA during SSE could be monitored, demonstrating the potential of the approach as biofeedback for physiotherapy training. Full article

Background: Microperimetric biofeedback training improved visual acuity and fixation stability in patients who previously underwent macular surgery. We aimed to compare the functional results of biofeedback training with the standard of care in patients who underwent successful inverted Internal Limiting Membrane (ILM)-flap technique for high myopic macular holes (hMMH). Methods: This was a retrospective, comparative, cohort study. Patients with hMMH after surgical hole closure underwent microperimetric biofeedback using structured light stimulus plus acoustic tone (n = 12; Biofeedback) or standard of care with scheduled visits (n = 11; Control). Best-corrected visual acuity, retinal sensitivity at central 12° (RS) and 4° (CRS) with a mean deviation at central 12° (MD), and fixation stability as bivariate contour ellipse area (BCEA 68%, 95%, and 99%) were assessed at baseline and month 1, 3, 6, and 12. The Mann–Whitney test was used to test the difference between the groups. Results: Baseline functional parameters were not significantly different among the groups. BCVA significantly improved in each group (Biofeedback, p = 0.002; Control, p ≤ 0.02) at all follow-up visits. CRS significantly improved at 6 (p = 0.03) and 12 (p = 0.01) months in the Biofeedback group and at month 12 (p = 0.01) in the Control group. RS (p = 0.001) and MD (p = 0.005) improved at the last follow-up only in the trained group. After training, BCEA 68% and 95% significantly improved (6 and 12 months, p < 0.05). The Biofeedback group had better results in RS (p ≤ 0.02), CRS (p ≤ 0.02), and BCEA 68%, 95%, and 99% (p ≤ 0.01) compared to the Control at all follow-ups. BCVA and MD were better in the Biofeedback group at month 3 (p = 0.01), and month 3 (p = 0.01) and 12 (p = 0.003), respectively. Conclusions: Microperimetric biofeedback can increase retinal sensitivity and stabilize fixation better than the standard care over months after a successful inverted ILM-flap for hMMH. Full article

Brain plasticity is the capacity of cerebral neurons to change, structurally and functionally, in response to experiences. This is an essential property underlying the maturation of sensory functions, learning and memory processes, and brain repair in response to the occurrence of diseases and trauma. In this field, the visual system emerges as a paradigmatic research model, both for basic research studies and for translational investigations. The auditory system remains capable of reorganizing itself in response to different auditory stimulations or sensory organ modification. Acoustic biofeedback training can be an effective way to train patients with the central scotoma, who have poor fixation stability and poor visual acuity, in order to bring fixation on an eccentrical and healthy area of the retina: a pseudofovea. This review article is focused on the cellular and molecular mechanisms underlying retinal sensitivity changes and visual and auditory system plasticity. Full article

Background: Despite the high closure rate of large macular hole (LMH) after surgery, visual recovery is often worse than expected. Microperimetric biofeedback can improve visual function in macular pathologies. We evaluated the efficacy of biofeedback on macular function after successful inverted flap technique for LMH. Methods: In this prospective comparative study, 26 patients after LMH surgical closure were enrolled. The whole sample was equally divided into two groups. In Group 1 (trained), patients underwent a double cycle of microperimetric biofeedback, using structured light stimulus plus acoustic tone; in Group 2 (control), patients underwent scheduled visits. We analyzed visual acuity, retinal sensitivity at central 12° (macular sensitivity, MS) and 4° (central macular sensitivity, CMS), and fixation stability over twelve months. Results: Visual acuity improved mainly in the trained group, without any significant differences between the groups (p > 0.05). Only after training did MS significantly improve (p = 0.01). CMS more significantly improved in the trained (p < 0.001) than the control group (p < 0.01) (Group 1 vs. 2, p = 0.004). Only in the trained group did fixation significantly improve (3 months, p ≤ 0.03; 12 months, p ≤ 0.01). An equality test on matched data confirmed a greater significant improvement of CMS (p ≤ 0.02) at all follow-up and fixation (p ≤ 0.02) at last follow-up after training. Conclusions: Microperimetric biofeedback consolidates and increases the improvement of retinal sensitivity and fixation gained after successful inverted flap technique. Full article