35 research outputs found
Rasch-Built Measure of Pleasant Touch through Active Fingertip Exploration
Background: Evidence suggests that somatic sensation has a modality for pleasant touch. Objective: To investigate pleasant touch at the fingertip level (i.e., glabrous skin site) through the elaboration of a linear unidimensional scale that measures (i) various materials according to the level of pleasantness they elicit through active fingertip explorations and (ii) subjects according to their pleasantness leniency levels. Subjects: We enrolled 198 healthy subjects without any neurological disease. Methods: Blindfolded subjects actively explored 48 materials with their index fingertips and reported the perceived pleasantness of each on a 4-level scale. The fingertip moisture levels on each subject were measured before the experimental session. Data were analyzed using the Rasch model. Results: We elaborated unidimensional linear scale that included 37 materials according to their pleasantness of touch. The pleasantness level of 21 materials was perceived differently, depending on the fingertip moisture levels of the subjects. Conclusion: Based on our findings, we formulated a Pleasant Touch Scale. Fingertip moisture levels appeared to be a major factor for (un)pleasant feelings during active exploration
Sensory and Emotional Perception of Wooden Surfaces through Fingertip Touch
Previous studies on tactile experiences have investigated a wide range of material surfaces across various skin sites of the human body in self-touch or other touch modes. Here, we investigate whether the sensory and emotional aspects of touch are related when evaluating wooden surfaces using fingertips in the absence of other sensory modalities. Twenty participants evaluated eight different pine and oak wood surfaces, using sensory and emotional touch descriptors, through the lateral motion of active fingertip exploration. The data showed that natural and smooth wood surfaces were perceived more positively in emotional touch than coated surfaces. We highlight the importance of preserving the naturalness of the surface texture in the process of wood-surface treatment so as to improve positive touch experiences, as well as avoid negative ones. We argue that the results may offer possibilities in the design of wood-based interior products with a view to improving consumer touch experiences.Peer reviewe
Haptics: Science, Technology, Applications
This open access book constitutes the proceedings of the 12th International Conference on Human Haptic Sensing and Touch Enabled Computer Applications, EuroHaptics 2020, held in Leiden, The Netherlands, in September 2020. The 60 papers presented in this volume were carefully reviewed and selected from 111 submissions. The were organized in topical sections on haptic science, haptic technology, and haptic applications. This year's focus is on accessibility
Haptics: Science, Technology, Applications
This open access book constitutes the proceedings of the 12th International Conference on Human Haptic Sensing and Touch Enabled Computer Applications, EuroHaptics 2020, held in Leiden, The Netherlands, in September 2020. The 60 papers presented in this volume were carefully reviewed and selected from 111 submissions. The were organized in topical sections on haptic science, haptic technology, and haptic applications. This year's focus is on accessibility
Electroencephalographic Responses to Frictional Stimuli: Measurement Setup and Processing Pipeline
Tactility is a key sense in the human interaction with the environment. The understanding of
tactile perception has become an exciting area in industrial, medical and scienti c research with an
emphasis on the development of new haptic technologies. Surprisingly, the quanti cation of tactile
perception has, compared to other senses, only recently become a eld of scienti c investigation.
The overall goal of this emerging scienti c discipline is an understanding of the causal chain
from the contact of the skin with materials to the brain dynamics representing recognition of
and emotional reaction to the materials. Each link in this chain depends on individual and
environmental factors ranging from the in uence of humidity on contact formation to the role of
attention for the perception of touch.
This thesis reports on the research of neural correlates to the frictional stimulation of the human
ngertip. Event-related electroencephalographic potentials (ERPs) upon the change in ngertip
friction are measured and studied, when pins of a programmable Braille-display were brought into
skin contact. In order to contribute to the understanding of the causal chain mentioned above,
this work combines two research areas which are usually not connected to each other, namely
tribology and neuroscience. The goal of the study is to evaluate contributions of friction to the
process of haptic perception. Key contributions of this thesis are:
1) Development of a setup to simultaneously record physical forces and ERPs upon tactile
stimulation.
2) Implementation of a dedicated signal processing pipeline for the statistical analysis of ERP
-amplitudes, -latencies and -instantaneous phases.
3) Interpretation of skin friction data and extraction of neural correlates with respect to varying
friction intensities.
The tactile stimulation of the ngertip upon raising and lowering of di erent lines of Braille-pins
(one, three and ve) caused pronounced N50 and P100 components in the event-related ERPsequences,
which is in line with the current literature. Friction between the ngertip and the
Braille-system exhibited a characteristic temporal development which is attributed to viscoelastic
skin relaxation. Although the force stimuli varied by a factor of two between the di erent Braillepatterns,
no signi cant di erences were observed between the amplitudes and latencies of ERPs
after standard across-trial averaging. Thus, for the rst time a phase measure for estimating singletrial
interactions of somatosensory potentials is proposed. Results show that instantaneous phase
coherency is evoked by friction, and that higher friction induces stronger and more time-localized
phase coherencyDie TaktilitÀt ist ein zentraler Sinn in der Interaktion mit unserer Umwelt. Das Bestreben,
fundierte Erkenntnisse hinsichtlich der taktilenWahrnehmung zu gewinnen erhÀlt groÿen Zuspruch
in der industriellen, medizinischen und wissenschaftlichen Forschung, meist mit einem Fokus auf
der Entwicklung von haptischen Technologien. Erstaunlicherweise ist jedoch die wissenschaftliche
Quanti zierung der taktilen Wahrnehmung, verglichen mit anderen SinnesmodalitÀten, erst seit
kurzem ein sich entwickelnder Forschungsbereich. Fokus dieser Disziplin ist es, die kognitive und
emotionale Reaktion nach physischem Kontakt mit Materialien zu beschreiben, und die kausale
Wirkungskette von der BerĂŒhrung bis zur Reaktion zu verstehen. Dabei unterliegen die einzelnen
Faktoren dieser Kette sowohl individuellen als auch externen Ein ĂŒssen, welche von der Luftfeuchtigkeit
wĂ€hrend des Kontaktes bis hin zur Rolle der Aufmerksamkeit fĂŒr die Wahrnehmung
reichen.
Die vorliegende Arbeit beschÀftigt sich mit der Untersuchung von neuronalen Korrelaten nach
Reibungsstimulation des menschlichen Fingers. Dazu wurden ReibungsÀnderungen, welche durch
den Kontakt der menschlichen Fingerspitze mit schaltbaren Stiften eines Braille-Display erzeugt
wurden, untersucht und die entsprechenden neuronalen Korrelate aufgezeichnet. Um zu dem Verst
Ă€ndnis der oben erwĂ€hnten Wirkungskette beizutragen, werden AnsĂ€tze aus zwei fĂŒr gewöhnlich
nicht zusammenhÀngenden Forschungsbereichen, nÀmlich der Tribologie und der Neurowissenschaft,
kombiniert. Folgende BeitrÀge sind Hauptbestandteile dieser Arbeit:
1) Realisierung einer Messumgebung zur simultanen Ableitung von KrÀften und ereigniskorrelierten
Potentialen nach taktiler Stimulation der Fingerspitze.
2) Aufbau einer speziellen Signalverarbeitungskette zur statistischen Analyse von stimulationsabh
Ă€ngigen EEG -Amplituden, -Latenzen und -instantanen Phasen.
3) Interpretation der erhobenen Reibungsdaten und Extraktion neuronaler Korrelate hinsichtlich
variierender StimulationsintensitÀten.
Unsere Resultate zeigen, dass die taktile Stimulation der Fingerspitze nach Anheben und Senken
von Braille-Stiften zu signi kanten N50 und P100 Komponenten in den ereigniskorrelierten Potentialen
fĂŒhrt, im Einklang mit der aktuellen Literatur. Die Reibung zwischen der Fingerspitze
und dem Braille-System zeigte einen charakteristischen Signalverlauf, welcher auf viskoelastische
Hautrelaxation zurĂŒckzufĂŒhren ist. Trotz der um einen Faktor zwei verschiedenen Intensit
Ă€tsunterschiede zwischen den Stimulationsmustern zeigten sich keine signi kanten Unterschiede
zwischen den einfach gemittelten Amplituden der evozierten Potentialen. Erstmalig wurde ein
Phasen-MaĂż zur Identi zierung von Unterschieden zwischen somatosensorischen "single-trial" Interaktionen
angewandt. Diese Phasenanalyse zeigte, im Gegensatz zur Amplituden- und Latenzanalyse,
deutlichere und signi kantere Unterschiede zwischen den Stimulationsparadigmen. Es
wird gefolgert, dass KohÀrenz zwischen den Momentanphasen durch Reibungsereignisse herbeigef
ĂŒhrt wird und dass durch stĂ€rkere Reibung diese KohĂ€renz, im zeitlichen Verlauf, stĂ€rker und
lokalisierter wird
Enhancing the E-Commerce Experience through Haptic Feedback Interaction
The sense of touch is important in our everyday lives and its absence makes it difficult to explore and manipulate everyday objects. Existing online shopping practice lacks the opportunity for physical evaluation, that people often use and value when making product choices. However, with recent advances in haptic research and technology, it is possible to simulate various physical properties such as heaviness, softness, deformation, and temperature. The research described here investigates the use of haptic feedback interaction to enhance e-commerce product evaluation, particularly haptic weight and texture evaluation. While other properties are equally important, besides being fundamental to the shopping experience of many online products, weight and texture can be simulated using cost-effective devices.
Two initial psychophysical experiments were conducted using free motion haptic exploration in order to more closely resemble conventional shopping. One experiment was to measure weight force thresholds and another to measure texture force thresholds. The measurements can provide better understanding of haptic device limitation for online shopping in terms of the availability of different stimuli to represent physical products. The outcomes of the initial psychophysical experimental studies were then used to produce various absolute stimuli that were used in a comparative experimental study to evaluate user experience of haptic product evaluation.
Although free haptic exploration was exercised on both psychophysical experiments, results were relatively consistent with previous work on haptic discrimination. The threshold for weight force discrimination represented as downward forces was 10 percent. The threshold for texture force discrimination represented as friction forces was 14.1 percent, when using dynamic coefficient of friction at any level of static coefficient of friction. On the other hand, the comparative experimental study to evaluate user experience of haptic product information indicated that haptic product evaluation does not change user performance significantly. However, although there was an increase in the time taken to complete the task, the number of button click actions tended to decrease. The results showed that haptic product evaluation could significantly increase the confidence of shopping decision. Nevertheless, the availability of haptic product evaluation does not necessarily impose different product choices but it complements other selection criteria such as price and appearance.
The research findings from this work are a first step towards exploring haptic-based environments in e-commerce environments. The findings not only lay the foundation for designing online haptic shopping but also provide empirical support to research in this direction
Spatio-Temporal and Multisensory Integration: the relationship between sleep and the cerebellum
Does the cerebellum sleep? If so, does sleep contribute to cerebellar cognition? In this thesis, the sleep contribution to the consolidation process of spatial-temporal and multisensory integration was investigated in relation to the human cerebellum. Multiple experimental approaches were used to answer research questions addressed in the various chapters. Summarizing the evidence of the electrophysiology and neuroimaging studies, in Chapter1 we present intriguing evidence that the cerebellum is involved in sleep physiology, and that cerebellar-dependent memory formation can be consolidated during sleep. In Chapter 2, using functional neuroimaging in healthy participants during various forms of the Serial interception sequential learning (SISL) task, i.e., predictive timing, motor coordination, and motor imagination, we assessed the cerebellar involvement in spatio-temporal predictive timing; and possible cerebellar interactions with other regions, most notably the hippocampus. In Chapter 3, we add to the findings of Chapter 2 that indicate the cerebellum and hippocampus are involved in the task, by showing that more than simply activated, the cerebellum is a necessary and responsible region for the establishment of the spatio-temporal prediction. This follows from the deficits in behavioral properties of the predictive and reactive timing in the cerebellar ataxia type 6 patients, using the modified version of the SISL task. In Chapter 4, we assessed the subsequent post-interval behavioral performances on the learning of the fixed and random timing sequences in the SISL task, comparing a sleep group and wake group in healthy participants. Our findings show that sleep consolidates the process of cerebellar-dependent spatio-temporal integration. In Chapter 5, we investigated the establishment of visual-tactile integration during sleep through the examination of tactile motion stimulation during sleep and showed that, subsequent to sleep, directional visual motion discrimination i