Novel Tactile Stimulation Using A Vibratory Foot Orthosis: A Preliminary Study

Tactile loss caused by diabetic peripheral neuropathy (DPN) might result in foot ulceration and lower extremity amputation. Neurorehabilitation with a vibrating insole is one of the novel therapies for improving tactile sensibility. In this preliminary study, a vibratory foot orthosis (VFO) in conjunction with a random square wave pulse stimulus and pseudorandom white noise (PRWN) via a stochastic resonance (SR) method was newly designed for tactile stimulation. Effectiveness of using the VFO to stimulate tactile sensation was investigated in ten DPN patients. The pretest and posttest outcomes were determined by the vibration perception threshold (VPT) values at the 1st metatarsophalangeal joint (MTP) and 5th MTP. The results demonstrated that novel tactile stimulation by the VFO could reduce the VPT values by 11.33%, P<.001, 1st MTP (left foot); 10.44%, P=.002, 5th MTP (left foot); 8.96%, P=.001, 1st MTP (right foot); and 8.92%, P=.003, 5th MTP (right foot). In conclusion, a new design for tactile stimulation using the VFO can improve tactile sensation in DPN. The prototype of this developed VFO can offer excellent vibratory stimulation while being non-invasive and safe to use. An orthotic design for diabetic foot and a total contact design of the VFO can alleviate the challenges of a previous vibrating insole. The VFO might contribute to avoid foot ulcers, recurrent foot ulcers, and lower limb impairments. Significantly, the VFO may aid in the prevention of lower limb disabilities and be beneficial for neurorehabilitation.