Dynamic Tactile Sensation Research Articles

Effects of Cognitive Exercise Therapy on Tactile Sensations of the Hands and Activities of Daily Living in Stroke Patients

Background/Objectives: The aim of present study was to evaluate the effects of cognitive exercise therapy (CET) on tactile sensations of the hands and activities of daily living in stroke patients.Method/Statistical Analysis: A total of 14 stroke patients with impaired hand sensations were participated and were randomly assigned to the CET group or the traditional occupational therapy (TOT) group. Patients in the CET group performed cognitive tasks using their spatial and tactile senses, whereas those in the TOT group received traditional occupational therapy. The intervention periods of the two groups were 30 min per day, five-times per week for four weeks. All participations were assessed before and after intervention with light touch sensation using the Mono-Filament, two-point discrimination sensation using the Disk-Criminator (static and dynamic tactile sensations), and the modified Barthel index (MBI) for activities of daily living ability.Findings: The CET group appeared significant improvements in static and dynamic two-point discrimination, and the MBI before and after the intervention. Also, the TOT group showed a significant improvement in MBI after intervention. At post-test, the CET group showed significant improvements in two-point discrimination and light touch compared to the TOT group.Improvements/Applications: These findings suggest that CET can induce improvement of the tactile sensations of the hands in stroke patients. Thus, we suggest that CET can be used for tactile-sensory rehabilitation of patients with stroke in clinic.

REVEL

REVEL is an augmented reality (AR) tactile technology that allows for change to the tactile feeling of real objects by augmenting them with virtual tactile textures using a device worn by the user. Unlike previous attempts to enhance AR environments with haptics, we neither physically actuate objects or use any force- or tactile-feedback devices, nor require users to wear tactile gloves or other apparatus on their hands. Instead, we employ the principle of reverse electrovibration where we inject a weak electrical signal anywhere on the user body creating an oscillating electrical field around the user's fingers. When sliding his or her fingers on a surface of the object, the user perceives highly distinctive tactile textures augmenting the physical object. By tracking the objects and location of the touch, we associate dynamic tactile sensations to the interaction context. REVEL is built upon our previous work on designing electrovibration-based tactile feedback for touch surfaces [Bau, et al. 2010]. In this paper we expand tactile interfaces based on electrovibration beyond touch surfaces and bring them into the real world. We demonstrate a broad range of application scenarios where our technology can be used to enhance AR interaction with dynamic and unobtrusive tactile feedback.

REVEL

REVEL is an augmented reality (AR) tactile technology that allows for change to the tactile feeling of real objects by augmenting them with virtual tactile textures using a device worn by the user. Unlike previous attempts to enhance AR environments with haptics, we neither physically actuate objects or use any force- or tactile-feedback devices, nor require users to wear tactile gloves or other apparatus on their hands. Instead, we employ the principle of reverse electrovibration where we inject a weak electrical signal anywhere on the user body creating an oscillating electrical field around the user's fingers. When sliding his or her fingers on a surface of the object, the user perceives highly distinctive tactile textures augmenting the physical object. By tracking the objects and location of the touch, we associate dynamic tactile sensations to the interaction context. REVEL is built upon our previous work on designing electrovibration-based tactile feedback for touch surfaces [Bau, et al. 2010]. In this paper we expand tactile interfaces based on electrovibration beyond touch surfaces and bring them into the real world. We demonstrate a broad range of application scenarios where our technology can be used to enhance AR interaction with dynamic and unobtrusive tactile feedback.

Psychophysical correlates in adults with sensory modulation disorder

Purpose: Individuals with sensory modulation disorder (SMD) demonstrate abnormal responses to naturally occurring stimuli in a manner that interferes with daily life activities. This study is the first study applying quantitative sensory testing to characterize the somatosensory sensitivity of adults with SMD. Method: One hundred and fifty one adults (68 males and 83 females) were tested comparing 91 SMD to 60 SMD-free, control individuals. Group placement (SMD vs. SMD-free) was determined using the Sensory Responsiveness Questionnaire (SRQ). Sensory detection thresholds for skin warming, cooling, punctate dynamic tactile sensation, vibration and thermal pain thresholds for heat and cold stimuli were determined at several body sites. Pinprick pain and prickliness were also assessed, as well as the duration and intensity of the after-sensations of prickliness and pain evoked by the prickly stimuli. Results: Compared to control adults, individuals with SMD showed significantly higher pain intensity to prickle stimuli, marginally higher pain intensity to pinprick and hypoesthesia to punctate dynamic tactile sensation at one of two sites tested. Conclusions: These results are in line with our previous study that investigated children with SMD using the same stimuli, and found similar results. We suggest a CNS involvement as the underlying mechanisms in SMD.

New Magnetic Microactuator Design Based on PDMS Elastomer and MEMS Technologies for Tactile Display.

Highly efficient tactile display devices must fulfill technical requirements for tactile stimulation, all the while preserving the lightness and compactness needed for handheld operation. This paper focuses on the elaboration of highly integrated magnetic microactuators for tactile display devices. FEM simulation, conception, fabrication, and characterization of these microactuators are presented in this paper. The current demonstrator offers a 4 × 4 flexible microactuator array with a resolution of 2 mm. Each actuator is composed of a Poly (Dimethyl-Siloxane) (PDMS) elastomeric membrane, magnetically actuated by coil-magnet interaction. It represents a proof of concept for fully integrated MEMS tactile devices, with fair actuation forces provided for a power consumption up to 100 mW per microactuator. The prototypes are destined to provide both static and dynamic tactile sensations, with an optimized membrane geometry for actuation frequencies between DC and 350 Hz. On the basis of preliminary experiments, this display device can offer skin stimulations for various tactile stimuli for applications in the fields of Virtual Reality or Human-Computer Interaction (HCI). Moreover, the elastomeric material used in this device and its global compactness offer great advantages in matter of comfort of use and capabilities of integration in haptic devices.

Psychophysical correlates in children with sensory modulation disorder (SMD)

Sensory modulation disorder (SMD), affecting ~ 5% of children, is characterized by sensory over or under-responsiveness to a range of stimuli in several modalities. Children with over-responsiveness (SOR) demonstrate increased aversion to certain natural stimuli that manifests as increased distress and avoidance behaviors to common stimuli, accompanied by abnormal electrodermal responses and brain evoked potentials to various stimuli. This study is the first to use quantitative sensory testing to characterize the somatosensory sub-modalities of children with SMD. Seventy eight children aged 6–10 years (44 SMD children and 34 classmate controls) were tested. A diagnosis of SMD and SMD-free using the Short Sensory Profile was ascertained by the Sensory Profile Questionnaire, both completed by participants' mothers. Sensory detection thresholds for skin warming, cooling, punctate dynamic tactile sensation, vibration and thermal pain thresholds for heat and cold were determined at several body sites. Pain and prickle intensities for pinprick and prickly stimuli and the duration and intensity of the after-sensations of prickliness and pain evoked by the prickle stimuli were assessed. Compared to the control children, SMD children showed significant cool hypoesthesia, higher pain intensity to pinprick and to prickly stimuli, and significantly more pain after-sensation to the prickly stimuli. No significant differences between groups were found in most of the sensory and pain thresholds at any tested site. These results indicate, for the first time, that children with SMD perceive more pain, and that their pain lasts longer. Our results demonstrate that SOR does not imply lowered sensory thresholds but abnormal processing suprathreshold noxious stimuli.