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.

A white cane is conventionally used by visually impaired persons to assist their mobility. To learn its proper operation, training by an orientation & mobility specialist is necessary. However, because the number of specialists is limited, visually impaired persons often do not receive sufficient training. To rectify this issue, a training environment in which the visually impaired can train independently is required. This paper proposes a training system that enables the visually impaired to learn white cane techniques using illusory pulling cues. Specifically, in the white cane touch technique, which is a basic white cane technique, a system that targets the swing width of the white cane is presented by illusory pulling cues. To verify the efficacy of the system, a prototype was implemented and evaluated via user tests. The results confirmed that the error of the swing width of the white cane decreased following use of the proposed system. The proposed system will contribute to the development of the mobility of the visually impaired by enabling them to train with the white cane independently and spontaneously, thereby reducing the workload of specialists.

To understand basic tactile perception using white canes, we compared tapping (two times) and pushing (two times) methods using the index finger and using a white cane, with and without accompanying auditory information. Participants were six visually impaired individuals who used a white cane to walk independently in their daily lives. For each of the tapping and pushing and sound or no sound conditions, participants gave magnitude estimates for the hardness of rubber panels. Results indicated that using a white cane produces sensitivity levels equal to using a finger when accompanied by auditory information, and suggested that when using a white cane to estimate the hardness of a target, it is most effective to have two different modalities of tactile and auditory information derived from tapping.

The purpose of this study is to develop smart equipment to quantify plantar tactile sensibility for the early diagnosis and tracking of peripheral neuropathy caused by diabetes mellitus. In this paper, we offer a new testing system that is composed of a plantar tactile stimulation platform with a small moving contactor to stretch the skin tangentially, a response switch for each tactile stimulus, a motor control box, and a personal computer (PC) for psychophysical data processing. This quantitative sensory testing system has detailed measurements available and is easy to use compared with the conventional testing devices, such as von Frey monofilaments, pin-prick testing devices, and current perception threshold testers. When using our testing system in a weight-bearing position, we observed that the plantar tactile thresholds for the tangential stretching stimulus on the plantar surface of the foot ranged from approximately 10 um to 30 um for healthy subjects. However, the threshold for a subject with diabetes was nearly three times higher than that for healthy subjects. The significant difference between these values suggests that the plantar sensory evaluation system using the lateral skin stretch stimulation can be used for early diagnosis, for the accurate staging of diabetic neuropathy, and for evaluating its progression noninvasively in a clinic and at home.

The white cane plays a vital role in the independent mobility support of the visually impaired. Allowing the recognition of target attributes through the contact of a white cane is an important function. We have conducted research to obtain fundamental knowledge concerning the exploration methods used to perceive the hardness of an object through contact with a white cane. This research has allowed us to examine methods that enhance accuracy in the perception of objects as well as the materials and structures of a white cane. Previous research suggest considering the roles of both auditory and tactile information from the white cane in determining objects' hardness is necessary. This experimental study examined the ability of people to perceive the hardness of an object solely through the tapping sounds of a white cane (i.e., auditory information) using a method of magnitude estimation. Two types of sounds were used to estimate hardness: 1) the playback of recorded tapping sounds and 2) the sounds produced on-site by tapping. Three types of handgrips were used to create different sounds of tapping on an object with a cane. The participants of this experiment were five sighted university students wearing eye masks and two totally blind students who walk independently with a white cane. The results showed that both sighted university students and totally blind participants were able to accurately judge the hardness of an object solely by using auditory information from a white cane. For the blind participants, different handgrips significantly influenced the accuracy of their estimation of an object's hardness.