There is no standard clinically adaptable criterion for assessing plantar sensation for pre- and post-intervention comparisons. Studies using Semmes–Weinstein monofilaments (SWMs) to investigate intervention effects on plantar sensation vary in procedure and do not consider measurement errors. This study aimed to develop a simple criterion using SWMs to assess plantar sensation, determine the measurement error range, and identify areas of low error. Six examiners assessed 87 healthy young adults in Experiment 1, while two examiners assessed 10 participants in Experiment 2. Filaments were graded from 1 to 20 based on increasing diameter. The smallest grade that could be perceived for three sequential stimuli was used as the criterion (smallest perceivable grade, SPG). The SPG was significantly smaller at the hallux and larger at the heel than at other sites. There were no significant differences between the SPG of the repeated tests performed by the same versus different examiners. The interquartile range of the differences was <±3 at all sites. Thus, our criteria were reliable in evaluating the effects of plantar sensation interventions, especially at the heel and the middle of the metatarsal heads and could contribute to the development of more effective treatments for plantar sensations.

Virtual reality (VR)-guided exercise therapy using mediVR KAGURA has been reported to improve gait function by extending the arm to spatial targets while sitting. We aimed to investigate toe and trunk–pelvic function and plantar sensation during gait in a postoperative patient with hallux valgus. A 60-year-old woman, whose foot deformities had improved 6 months earlier, participated in the study. The exercise therapy interventions were performed twice weekly for 15 min. This study used an A-B-A design: 1-week pre-phase, 3-week intervention phase, and 2-week post-phase. The plantar pressure distribution and thoracic and pelvic displacements during gait were recorded at the end of each phase. The tactile pressure thresholds of the foot were determined before and after each exercise. The maximum force and impulse under the hallux increased after the intervention. The sensory threshold of the hallux was reduced. The amplitude of the thoracic and pelvic displacement was shortened in lateral and extended in the vertical and progressional directions after the intervention. We found that a 3-week VR-guided exercise improved toe function, plantar sensation, and postural adjustment of the trunk and pelvis during gait in a patient who had undergone surgery for hallux valgus, and the effects continued for 2 weeks.

[Purpose] Virtual reality (VR) rehabilitation has become popular in the medical field. VR-guided exercises (VR-ge) have demonstrated positive effects on gait and trunk control. Trunk muscle activation, particularly that of the transversus abdominis (TrA), is responsible for these improvements. However, the difference in muscle activation between VR and real space remains unclear. Therefore, this study aimed to clarify the differences in trunk muscle activation during exercise therapy performed in VR and real space. [Participants and Methods] A total of 22 healthy male volunteers were divided into two equal groups: VR-ge and Control exercise (C-e) groups. Both groups performed reaching exercises in a seated position. Ultrasound imaging was used to measure the thicknesses of the right external oblique, internal oblique, and TrA muscles, both at rest and during the reaching exercises performed in six different directions. [Results] No significant differences were observed in TrA muscle thickness changes between the groups before the intervention. However, after the intervention, the VR-ge group showed significantly greater TrA muscle thickness changes during reaching compared to that of the C-e group. [Conclusion] VR-ge increased TrA activation during reaching compared to exercising in real space.