The purpose of this study is to examine the variability in sensory test of tactile results using Semmes-Weinstein monofilament (SWM). At present, several methods for measuring the tactile sensitivity are clinically used in diabetic peripheral neuropathy screening. One of these methods is a touch test that uses a device with nylon SWMs, i.e., SWMs embedded in a plastic handle. A small pushing force is applied at the handle to bow the filaments. Because of its ease and simplicity, the SWM test is conducted at the patient's bedside in a hospital. However, previous studies have reported some problems with this test. Studies have shown variations in the measured data, and it is uncertain whether these variations are caused by mechanical properties of the nylon fiber or by the motion of the operator's hands. We carried out two experiments to examine the effect of (1) the variability caused by the human operator conducting the SWM test on the test results and (2) the number of compressions of the SWM on the test results. In experiment 1, we measured the velocity of the operator's hand motion and the buckling force of the SWMs. The results showed variability in the hand motion of the operator conducting the SWM tests. In experiment 2, we measured the buckling force of the SWMs under a controlled velocity. We compared the buckling force of the SWMs through a number of trials. These results showed that the buckling force gradually decreases as the number of test cycles increase. In conclusion, we find that the accuracy of the SWM tests is a factor of the number of test cycles. Additionally, manual training for standardizing skills of medical staff members needs to be developed. Furthermore, the characteristics of the SWMs deteriorated over time. In future work, we aimto find a solution to minimize the variability in the SWM test results and develop a new testing system that uses tactile sensibility for diabetic peripheral neuropathy screening.

(1) Objective: This study was conducted with the objective of characterizing the variability of a force on a simulated skin surface using the Semmes–Weinstein monofilament test (SWMT). (2) Research Design and Methods: Two distinct experiments were performed to determine the effects of human hand motion variability on the monofilament buckling force, and to determine the monofilament’s mechanical properties using a positioning stage. (3) Results: In manual operation (by human hand motion), the buckling force over the ten compressions decreased by over 10%, and the human hand motion variations during the SWMT may have impacted the buckling force. When the SWMT was performed under manual control, the buckling force was closely correlated with the number of compressions. In automated operation (by positioning stage), the buckling force was affected not only by the number of compressions but also by both the velocity and the contact angle between the monofilament and the skin surface. (4) Conclusions: The buckling force decreased in ten successive compressions, independent of the hand motion. Hence, medical staff need to consider not only the operator’s hand motion but also the effect of repeated trials.

Maxillectomy for oral tumours often results in debilitating oral hypofunction, which markedly decreases quality of life. Dysphagia, in particular, is one of the most serious problems following maxillectomy. This study used swallowing sounds as a simple evaluation method to evaluate swallowing ability in maxillectomy patients with and without their obturator prosthesis placed. Twenty-seven maxillectomy patients (15 men, 12 women; mean age 66.0 ± 12.1 years) and 30 healthy controls (14 men, 16 women; mean age 44.9 ± 21.3 years) were recruited for this study. Participants were asked to swallow 4 mL of water, and swallowing sounds were recorded using a throat microphone. Duration of the acoustic signal and duration of peak intensity (DPI) were measured. Duration of peak intensity was significantly longer in maxillectomy patients without their obturator than with it (P < .05) and was significantly longer in maxillectomy patients without their obturator than in healthy controls (P < .025 after Bonferroni correction). With the obturator placed, DPI was significantly longer in maxillectomy patients who had undergone soft palate resection than in those who had not (P < .05). These results suggest swallowing ability in maxillectomy patients could be improved by wearing an obturator prosthesis, particularly during the oral stage. However, it is difficult to improve the oral stage of swallowing in patients who have undergone soft palate resection even with obturator placement.

An increase in the population of dysphagia patients due to an aging population has led to increased attention on examination methods based on swallowing sound as simple methods of screening aspiration. However, an issue with the conventional method of cervical auscultation is that its accuracy varies based on the examiner. Previous studies examined the use of throat microphones and acceleration sensors to examine the acoustic characteristics of swallowing sound. Nevertheless, extant studies to date did not reach a level of clinical application. This study focused on using a throat microphone that is conventionally used to measure swallowing sound and an AE sensor to measurement a high-frequency range equal to and exceeding 20 kHz (upper limit 2 MHz). The study involved measuring the sounds of swallowing water of healthy subjects and patients wearing palatal augmentation prosthesis who had done surgical operation to treat head and neck cancer with the objective of using swallowing sound for screening aspiration. Acoustic characteristics of measured swallowing sound were analyzed using probability distributions using Quantile-Quantile (Q-Q) plots and spectral analysis based on wavelet transform. The findings indicated that with respect to patients with PAP, the duration time of the swallowing sound and the Q-Q plot departure rate were both significantly higher when compared with those in healthy subjects. The analysis based on wavelet transform indicated that the AE sensor allowed measurements of waveforms at a higher frequency range when compared to those in the case of the throat microphone. Additionally, an increased frequency of higher-frequency signals was associated with patients with PAP when compared to healthy subjects. The results revealed that it is possible to measure waveforms in the high-frequency range by using the AE sensor. The findings suggested the validity of analysis of the swallowing sound based on probability distributions using the Q-Q plot to evaluate the swallowing sound.

Metal hydride (MH) actuators have a simple structure and a number of features that make them attractive for use in rehabilitation engineering and assistive technology. The MH actuator provides a high power-to-weight ratio, high-strain actuation, human-compatible softness, and noiseless operation, while being environmentally benign. On the other hand, there remain technical challenges to be overcome to improve the MH actuator regarding its speed of operation and energy efficiency, given the low heat conductivity of the MH powder that is used as the pressure generator for soft actuation. To overcome the issues of low heat conductivity and the handling of MH powder, we developed an MH paper, which is a special paper incorporating MH powder and carbon fiber, for use as a new pressure-generating element for a soft MH actuator system. In addition, the basic properties and structure of the proposed MH paper were investigated through scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and several thermodynamic experiments. The results of these experiments showed that the hydrogen absorption and desorption rates of the MH paper were significantly higher than those of the MH powder around room temperature.