Joint Contributions of Auditory, Proprioceptive and Visual Cues on Human Balance.

One's ability to maintain their center of mass within their base of support (i.e., balance) is believed to be the result of multisensory integration. Much of the research in this literature has focused on integration of visual, vestibular, and proprioceptive cues. However, several recent studies have found evidence that auditory cues can impact balance control metrics. In the present study, we sought to better characterize the impact of auditory cues on narrow stance balance task performance with different combinations of visual stimuli (virtual and real world) and support surfaces (firm and compliant). In line with past results, we found that reducing the reliability of proprioceptive cues and visual cues yielded consistent increases in center-of-pressure (CoP) sway metrics, indicating more imbalance. Masking ambient auditory cues with broadband noise led to less consistent findings; however, when effects were observed they were substantially smaller for auditory cues than for proprioceptive and visual cues - and in the opposite direction (i.e., masking ambient auditory cues with broadband noise reduced sway in some situations). Additionally, trials that used virtual and real-world visual stimuli did not differ unless participants were standing on a surface that disrupted proprioceptive cues; disruption of proprioception led to increased CoP sway metrics in the virtual visual condition. This is the first manuscript to report the effect size of different perturbations in this context, and the first to study the impact of acoustically complex environments on balance in comparison to visual and proprioceptive contributions. Future research is needed to better characterize the impact of different acoustic environments on balance.

Mechanical stimulation of a bioactive, functionalized PVDF-TrFE scaffold provides electrical signaling for nerve repair applications.

Traumatic nerve injuries have limited success in achieving full functional recovery, with current clinical solutions often including implementation of nerve grafts or the use of nerve conduits to guide damaged axons across injury gaps. In search of alternative, and complimentary solutions, piezoelectric biomaterials demonstrate immense potential for tissue engineering applications. Piezoelectric poly(vinylidene fluoride-triflouroethylene) (PVFD-TrFE) scaffolds can be harnessed to non-invasively stimulate and direct function of key peripheral nervous system (PNS) cells in regeneration strategies. In this study, electrospun PVDF-TrFE was characterized, fabricated into a 3D scaffold, and finally rendered bioactive with the incorporation of a cell-secreted, decellularized extracellular matrix (dECM). PVDF-TrFE scaffolds were characterized extensively for piezoelectric capacity, mechanical properties, and cell-material interactions with fibroblasts and Schwann cells. Through functionalization of PVDF-TrFE scaffolds with a native, cell-assembled dECM, the ability to promote cell adhesion and enhanced viability was also demonstrated. Additionally, incorporation of bioactive functionalization improved the assembly of key regenerative ECM proteins and regenerative growth factors. PVDF-TrFE scaffolds were then fabricated into a conduit design that retained key physical, chemical, and piezoelectric properties necessary for PNS repair. This work shows great promise for multi-cue, electrospun biomaterials for regeneration of the PNS in traumatic injury.