Tactile Function Research Articles

Cognitive-Motor Impairment in Manual Tasks in Adults With Type 2 Diabetes.

Adults with type 2 diabetes (T2D) experience decline in cognitive function compared with controls. Cognitive function is a major component in the performance of daily activities that involve motor components. The aim of this project was to evaluate working memory cognitive deficits and sensorimotor deficits in adults with T2D versus healthy participants. Ten community-dwelling persons with T2D and 10 age- and sex-matched healthy controls were recruited. Cognitive function, tactile function, motor function, and health state measures were evaluated. Reduced cognitive function, tactile function, and motor function were exhibited in the T2D group. Cognitive and motor functions remained impaired versus controls during tasks with both cognitive and motor components (dual tasks). Health state measures were found to covary with measures of interest. The conclusions of this article are as follows: (a) systemic deficits beyond tactile dysfunction contribute to reduced hand/finger function in T2D, and (b) participants with T2D demonstrate impairments in working memory, tactile function, and motor function.

Defining pleasant touch stimuli: a systematic review and meta-analysis.

Pleasantness is generally overlooked when investigating tactile functions. Addition of a pleasant stimulus could allow for a more complete characterisation of somatosensory function. The aims of this review were to systematically assess the methodologies used to elicit a pleasant sensation, measured via psychophysical techniques, and to perform a meta-analysis to measure the effect of brush stroking velocity on touch pleasantness. Eighteen studies were included in the systematic review, with five studies included in the meta-analysis. The review found that factors such as texture, velocity, force, and the duration of continuous stroking influence tactile evoked pleasantness. Specifically, using a soft material and stroking at a velocity of 3cm/s with light force is generally considered as particularly pleasant. The meta-analysis showed that a brush stroking velocity of 30cm/s was rated as less pleasant than 3cm/s, on the forearm. The present study collates the factors that are most likely to provide a stimulus to elicit a pleasant sensation. The results should be important for studies requiring a well-defined pleasant stimulus including neurosensory assessment protocols, allowing for a more complete multimodality assessment of somatosensory function.

Structural features and lamellar mechanoreceptors of the collared peccary’s tongue (Pecari tajacu, Linnaeus 1758)

Collared peccaries are omnivorous mammalians well known for presenting a prominent skin gland, known as scent gland. We’ve previously described the histological organization of the palate and lip of this peccary and found several small and large lamellar corpuscles (Vater-Pacini corpuscle) mostly grouped in small aggregates distributed along its lamina propria-submucosa. Here, we described the anatomic structure and histological organization of the tongue of the collared peccary by means of light microscopy. The main features were the presence of a prominent rostral anterior salivary gland and the widespread presence of lamellar corpuscles that could contribute to the tactile function of the tongue.

DIFFERENCES IN THE DEVELOPMENT OF TACTILE FUNCTIONS IN PARTIALLY SIGHTED CHILDREN IN RELATION TO CATEGORY AND TYPE OF VISUAL IMPAIRMENT

The aim of this study was to examine the differences in the development of tactile functions in visually impaired (amblyopic) children in relation to the category and type of visual impairment. In the study, 30 respondents with visual impairment, aged 7-13 and of both genders were examined. Tactile functions assessment was performed using the LuriaNebraska Tactile Functions Assessment Scale ('C3'). A t-test was used to examine the significance of arithmetic mean differences. With respect to the category of visual impairment, it was found that there were statistically significant differences in arithmetic means on three variables of tactile perception. Respondents have equally developed tactile functions in relation to the type of visual impairment

Design of Piezoelectric Actuator for Braille Module by Finite Element Method.

Piezoelectric actuators, exhibiting large displacement and torque, are attractive for use in a broad range of actuator applications. One of the important applications is a tactile device, e.g., refreshable Braille display. Piezoelectric actuation in the Braille module requires large torque and large displacement for the tactile sensing of the human finger. In this study, we design piezoelectric actuators for the tactile interface including a Braille cell by finite element method (FEM) simulations. FEM simulations allow us to capture the entire device physics and solve the coupled piezoelectricity/solid mechanics problem. We investigated the effect of the structure, geometric variation, and physical properties of the materials used on the displacement and torque force. The studied structure includes a trilayer bimorph consisting of piezoelectric and supporting layers, and a multilayer with multiple bimorphs. The simulation result provides a useful guide toward piezoelectric actuators of tactile function.

High-Speed High-Precision Proximity Sensor Subsuming Tactile Function

High-Speed High-Precision Proximity Sensor Subsuming Tactile Function

Effects of attachment type and palatal coverage on oral perception and patient satisfaction in maxillary implant-supported complete denture patients.

The effect of oral rehabilitation on the oral perception of implant-supported overdenture patients is a concern. This study evaluated the effects of the attachment type and palatal coverage on oral perception and patient satisfaction in maxillary implant-supported complete denture patients. The correlation between oral perceptual ability (OPA) and patient satisfaction in three groups was investigated. Group I consisted of dentate individuals (n = 40), Group II consisted of maxillary implant-supported complete denture patients with bar attachments and palatal coverage (n = 12), and Group III of maxillary implant-supported complete denture patients with magnetic attachments and palatal coverage (n = 14). In addition, implant-supported maxillary overdentures with bar attachments, with (Group II; n = 12) and without (Group IV; n = 18) palatal coverage, were examined in terms of patient satisfaction and OPA. The relationship between OPA and patient satisfaction was assessed with the Turkish version of the Oral Health Impact Profile-14 (OHIP-TR-14) satisfaction survey. To compare oral sensory function among the groups, tactile awareness and pressure awareness were assessed. There was no significant difference in OHIP-TR-14 scores between Groups II and III. In addition, there was no correlation between oral tactile function and patient satisfaction in Groups II and III. For patients with maxillary bar-retained implant-supported overdentures, palatal coverage did not affect the correlation between OPA and patient satisfaction, lateral pressure threshold, or tactile thickness threshold. According to the results of the study, whether maxillary implant-supported overdentures were made with a bar- or magnetic-type retainer, and whether bar-retained implant-supported overdentures had an open or closed palate did not affect the correlation between patient satisfaction and oral perception.

Psychophysics Behavior of Human Tactile Mechanism to Discriminate Extremely Thin Copper Foils.

In this study, our objective is to analyze human tactile mechanism behavior in recognizing extremely thin foils using the psychophysics method. Seven pairs of copper foils ranging in thickness from 20 ~ 150 μm were used in the experiment. We applied the method of constant stimuli to define the difference threshold between the materials. In order to increase the detection rate, contact between human tactile function and the metal foils was maintained. As a result, the Weber fraction c consistently reduces as thickness increases. However, the slope decrement is steep compared to previous experimentation (using stainless steel as base). We also validated the behavior of the undetected regions up to 150-μm thicknesses. This achievement was quite significant considering the higher thickness test ratio. In future, further comparison shall be made using different material type.

Potentials of Ultrahigh-Field MRI for the Study of Somatosensory Reorganization in Congenital Hemiplegia.

Reorganization of somatosensory function influences the clinical recovery of subjects with congenital unilateral brain lesions. Ultrahigh-field (UHF) functional MRI (fMRI) with the use of a 7 T magnet has the potential to contribute fundamentally to the current knowledge of such plasticity mechanisms. The purpose of this study was to obtain preliminary information on the possible advantages of the study of somatosensory reorganization at UHF fMRI. We enrolled 6 young adults (mean age 25 ± 6 years) with congenital unilateral brain lesions (4 in the left hemisphere and 2 in the right hemisphere; 4 with perilesional motor reorganization and 2 with contralesional motor reorganization) and 7 healthy age-matched controls. Nondominant hand sensory assessment included stereognosis and 2-point discrimination. Task-dependent fMRI was performed to elicit a somatosensory activation by using a safe and quantitative device developed ad hoc to deliver a reproducible gentle tactile stimulus to the distal phalanx of thumb and index fingers. Group analysis was performed in the control group. Individual analyses in the native space were performed with data of hemiplegic subjects. The gentle tactile stimulus showed great accuracy in determining somatosensory cortex activation. Single-subject gentle tactile stimulus showed an S1 activation in the postcentral gyrus and an S2 activation in the inferior parietal insular cortex. A correlation emerged between an index of S1 reorganization (distance between expected and reorganized S1) and sensory deficit (p < 0.05) in subjects with hemiplegia, with higher distance related to a more severe sensory deficit. Increase in spatial resolution at 7 T allows a better localization of reorganized tactile function validated by its correlation with clinical measures. Our results support the S1 early-determination hypothesis and support the central role of topography of reorganized S1 compared to a less relevant S1-M1 integration.

Somatosensory Plasticity in Pediatric Cerebral Palsy following Constraint-Induced Movement Therapy.

Cerebral palsy (CP) is predominantly a disorder of movement, with evidence of sensory-motor dysfunction. CIMT1 is a widely used treatment for hemiplegic CP. However, effects of CIMT on somatosensory processing remain unclear. To examine potential CIMT-induced changes in cortical tactile processing, we designed a prospective study, during which 10 children with hemiplegic CP (5 to 8 years old) underwent an intensive one-week-long nonremovable hard-constraint CIMT. Before and directly after the treatment, we recorded their cortical event-related potential (ERP) responses to calibrated light touch (versus a control stimulus) at the more and less affected hand. To provide insights into the core neurophysiological deficits in light touch processing in CP as well as into the plasticity of this function following CIMT, we analyzed the ERPs within an electrical neuroimaging framework. After CIMT, brain areas governing the more affected hand responded to touch in configurations similar to those activated by the hemisphere controlling the less affected hand before CIMT. This was in contrast to the affected hand where configurations resembled those of the more affected hand before CIMT. Furthermore, dysfunctional patterns of brain activity, identified using hierarchical ERP cluster analyses, appeared reduced after CIMT in proportion with changes in sensory-motor measures (grip or pinch movements). These novel results suggest recovery of functional sensory activation as one possible mechanism underlying the effectiveness of intensive constraint-based therapy on motor functions in the more affected upper extremity in CP. However, maladaptive effects on the less affected constrained extremity may also have occurred. Our findings also highlight the use of electrical neuroimaging as feasible methodology to measure changes in tactile function after treatment even in young children, as it does not require active participation.

Response characteristics of the cat somatosensory cortex following the mechanical stimulation to endodontically treated teeth with overextension

The overextension of filling materials may take place accidentally during an endodontic root canal treatment. Previous studies to understand the correlation between overfilling and paresthesia of teeth were inconsistent. In this study, an intrinsic signal optical imaging technique was employed as the objective tool to compare the response characteristics of the cat somatosensory cortex following mechanical stimulation applied to endodontically treated teeth with overextension (ETTWO) and natural teeth. Based on the evoked cortical response, the signal strength of the ETTWO was found to be significantly higher than that of the natural teeth. However, the tactile threshold of the ETTWO was significantly lower than that of the natural teeth. It was concluded that the tactile function of ETTWO is more sensitive than that of natural teeth, and that the overextension of filling materials can cause hyperesthesia of teeth after root canal treatment.

A Highly Sensitive Force Sensor with Fast Response Based on Interlocked Arrays of Indium Tin Oxide Nanosprings toward Human Tactile Perception

AbstractDevelopment of a sensor for recognizing tactile feeling is essential for realizing artificial systems that can perform human tactile functions for various applications. For achieving the capability of human tactile sensation, highly sensitive responses are required not only to static pressures but also to dynamic high‐frequency vibrations. Here, a highly sensitive force sensor based on interlocked arrays of vertically aligned indium tin oxide (ITO) nanospring structures fabricated on a flexible polyethylene naphthalate substrate is presented. The combination of rigid ITO on the flexible substrate, its unique nanoscale spring‐like geometry, and the interlocking configuration results in sensitive responses to both static and dynamic pressures with a sub‐millisecond response time over wide pressure and frequency ranges appropriate for human tactile perception. Consequently, the sensor is capable of classifying eight fabrics possessing complex patterns with 99.8% accuracy. In addition, a flexible 14 × 14 force sensor matrix array is demonstrated, thus demonstrating the integration capability.

Fast-Response and Low-Hysteresis Flexible Pressure Sensor Based on Silicon Nanowires

Flexible pressure sensors are the cornerstone of electronic skins with tactile function. However, flexible pressure sensors tend to have disadvantages of slow response speed and large hysteresis, which are caused mainly by the viscoelasticity and interfacial adhesion of flexible materials. In this letter, we adopted silicon nanowire (SiNW) arrays to fabricate a pressure sensor with a piezo-capacitance when the SiNWs are bending under pressure, which avoided the viscoelasticity and interfacial adhesion accompanying with common flexible materials. The sensor recorded unprecedented low hysteresis (~2.26%) and an extremely short response time (~3 ms). With high sensitivity (up to ~8.2 kPa <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> ), large response capacitance, ultralow detection limit (0.1 Pa), and good repeatability and stability, the sensor holds potential applications in advanced electronic skins, especially when high-precision and high-speed sensing are required.

Semiótica da arte para deficientes visuais

Este artigo tem como objetivo analisar o recurso de acessibilidade visual disponível no Museo Nacional de Artes Visuales (MNAV) de Montevidéu, Uruguai. Para tal, fez-se uma pesquisa de campo no espaço expositivo, onde foram identificados e delimitados em seu conjunto semiótico, os expositores, as pinturas e os painéis táteis. Especificamente os painéis táteis funcionam como dispositivos de interação sensível para os visitantes com deficiência visual. Tendo como recorte três obras pertencentes ao patrimônio artístico do país, de Juan Manuel Blanes, Carlos Federico Sáez e Joaquín Torres García, propõem-se um comparativo entre as placas de acessibilidade e as pinturas em si, levando em consideração preliminarmente, a abordagem peirciana sobre primeiridade, secundidade, terceiridade e ícone, índice e símbolo.

Changes in Tactile Function During Intensive Bimanual Training in Children With Unilateral Spastic Cerebral Palsy.

Recently, an intensive bimanual intervention using sensory enriched materials resulted in improved tactile function in children with unilateral spastic cerebral palsy (USCP), raising the question of whether the observed tactile function improvement was due to the sensory enriched environment or the bimanual intervention per se. The present study investigates whether a bimanual intensive intervention improves tactile function. Nineteen children with USCP received 90 hours of bimanual training without enriched environment. Primary outcomes: Manual Form Perception Test/MFPT, Grating Orientation Task/GOT. Children were assessed before, after the training, and at the 4-month follow-up. Significant improvements were observed in MFPT for the more affected hand ( P = .015). Larger stereognosis/MFPT improvements correlated with poorer baseline motor function. Intensive bimanual training alone was sufficient to improve stereognosis, though no improvement in GOT was observed. Present and previously published findings suggest that environmental tactile enrichment incorporated into a bimanual motor training may be needed to improve spatial discrimination/GOT in children with USCP.

A location- and sharpness-specific tactile electronic skin based on staircase-like nanowire patches.

Human skin can sense an external object in a location-specific manner, simultaneously recognizing whether it is sharp or blunt. Such tactile capability can be achieved in both natural and stretched states. It is impractical to mimic this tactile function of human skin by designing pixelated sensor arrays across our whole curvilinear human body. Here, we report a new tactile electronic skin sensor based on staircase-like vertically aligned gold nanowires (V-AuNWs). With a back-to-back linear or spiral assembly of two staircase structures into a single sensor, we are able to recognize pressure in a highly location-specific manner for both non-stretched and stretched states (up to 50% strain); with a concentric design on the fingertip, we can identify the sharpness of an external object. We believe that our strategy opens up a new route to highly specific second-skin-like tactile sensors for electronic skin (E-skin) applications.

High-Speed High-Precision Proximity Sensor Subsuming Tactile Function

High-Speed High-Precision Proximity Sensor Subsuming Tactile Function

A Case-Controlled Investigation of Tactile Reactivity in Young Children With and Without Global Developmental Delay.

Assessing tactile function among children with intellectual, motor, and communication impairments remains a clinical challenge. A case control design was used to test whether children with global developmental delays (GDD; n = 20) would be more/less reactive to a modified quantitative sensory test (mQST) compared to controls (n = 20). Reactivity was indexed by blinded behavioral coding across vocal, facial, and gross motor responses during the mQST. On average the children with GDD were significantly more reactive than controls to most tactile sensory modalities including light touch (p = .034), pin prick (p = .008), cool (p = .039), pressure (p = .037), and repeated von Frey (p = .003). The results suggest the mQST approach was feasible and highlights the GDD sample was more reactive than controls to a range of stimuli.

Response characteristics of the cat somatosensory cortex following the mechanical stimulation to non-vital and vital canine

Patients sometimes complain that non-vital teeth after root canal treatment (RCT) are paresthesia compared with vital teeth, and previous psychological studies on the tactile sensibility of non-vital teeth remained controversial. In the present study, intrinsic signal optical imaging, which served as an objective tool, was employed to compare the cortex response characteristics following forces applied to the cat non-vital and vital canines. Based on the evoked cortical responses, the response threshold, signal strength, spatial pattern, temporal dynamics and the preference of force direction, they were not significantly different between vital and non-vital canines. It seemed that the tactile sensibility of vital and non-vital teeth was comparable at the cortical response level, and pulpal receptors were not concerned in tactile function.

Complex neuroanatomy in the rostrum of the Isle of Wight theropod Neovenator salerii

The discovery of large, complex, internal canals within the rostra of fossil reptiles has been linked with an enhanced tactile function utilised in an aquatic context, so far in pliosaurids, the Cretaceous theropod Spinosaurus, and the related spinosaurid Baryonyx. Here, we report the presence of a complex network of large, laterally situated, anastomosing channels, discovered via micro-focus computed tomography (μCT), in the premaxilla and maxilla of Neovenator, a mid-sized allosauroid theropod from the Early Cretaceous of the UK. We identify these channels as neurovascular canals, that include parts of the trigeminal nerve; many branches of this complex terminate on the external surfaces of the premaxilla and maxilla where they are associated with foramina. Neovenator is universally regarded as a ‘typical’ terrestrial, predatory theropod, and there are no indications that it was aquatic, amphibious, or unusual with respect to the ecology or behaviour predicted for allosauroids. Accordingly, we propose that enlarged neurovascular facial canals shouldn’t be used to exclusively support a model of aquatic foraging in theropods and argue instead that an enhanced degree of facial sensitivity may have been linked with any number of alternative behavioural adaptations, among them defleshing behaviour, nest selection/maintenance or social interaction.