Static Touch Research Articles

Pupil dilation responds to the intrinsic social characteristics of affective touch

Affective Touch is characterized by both emotional and arousing dimensions that rely on specific features of a gentle human caress. In this study, we investigated whether and how both the nature of the touching effector (Human hand vs. Artificial hand) and touch type (Dynamic vs. Static) influenced the participants’ pupil dilation and their subjective experience during tactile stimulation. We observed that when participants received a dynamic touch, their pupil dilation increased more when the touch was produced by a human compared to an artificial hand. This discrimination was not present for static touch. Also, dynamic touch given by a human hand invoked a supralinear enhancement of pupil dilation indicating that the combination of these two features induced a stronger autonomic activation than the summed effects of each separately. Moreover, this specific type of touch was perceived as the most pleasant compared to all other tactile stimulations. Overall, our results suggest that pupil dilation could reflect the pleasant experience of human-to-human tactile interactions, supporting the notion that the autonomic nervous system is responsive to the emotional and hedonic aspects associated with Affective Touch as a part of a complex and holistic social experience, rather than solely reacting to its low-level sensory properties.

Pelvic Palpatory Tests in Manual Therapy and Osteopathy: A Critical Review of the Literature and Suggestions for New Research.

Manual therapists apply physical interventions to the entire structure of the body to promote healing, prevent pathologies, and improve patient health. In osteopathic practice, palpatory evaluation is considered a fundamental clinical practice requirement for identifying somatic dysfunction. Most of the articles published in this area have failed to demonstrate a level of reproducibility that supports palpation in evidence-based clinical practice. When considering the poor reliability of the palpatory tests highlighted in the literature, a discrepancy is noted with what is known about the tactile sensitivity of human hands. For static touch, the minimum size that can be detected, in the absence of applied movement or vibration, is approximately 0.2 mm. Yet, it seems that this high level of precision is insufficient to ensure reliability in the tests used to evaluate osteopathic somatic dysfunction. The purpose that underscores this article is to determine how these two contradictory elements, high sensitivity and low reliability, can be present in palpatory tests. The article reports the literature findings regarding palpatory tests of pelvic, which is an important structure for clinical purposes. Additionally, a critical review of how these studies were conducted is provided to identify any elements that may justify the obtained results. Following recent accredited guidelines present in the literature, we propose suggestions on vision training methods, manual perception refinement training, the search for anatomical markers, and the position of the examiner in relation to the examineethat may be useful for future studies on the topic covered by the article.

Effectiveness of craniosacral therapy, Bowen therapy, static touch and standard exercise program on sleep quality in fibromyalgia syndrome: A randomized controlled trial

BackgroundSleep disturbance is commonly seen in fibromyalgia syndrome (FMS); however, high quality studies involving manual therapies that target FMS-linked poor sleep quality are lacking for the Indian population. ObjectiveCraniosacral therapy (CST), Bowen therapy and exercises have been found to influence the autonomic nervous system, which plays a crucial role in sleep physiology. Given the paucity of evidence concerning these effects in individuals with FMS, our study tests the effectiveness of CST, Bowen therapy and a standard exercise program against static touch (the manual placebo group) on sleep quality in FMS. Design, setting, participants and interventionA placebo-controlled randomized trial was conducted on 132 FMS participants with poor sleep at a hospital in Bangalore. The participants were randomly allocated to one of the four study groups, including CST, Bowen therapy, standard exercise program, and a manual placebo control group that received static touch. CST, Bowen therapy and static touch treatments were administered in once-weekly 45-minute sessions for 12 weeks; the standard exercise group received weekly supervised exercises for 6 weeks with home exercises until 12 weeks. After 12 weeks, all study participants performed the standard exercises at home for another 12 weeks. Main outcome measuresSleep quality, pressure pain threshold (PPT), quality of life and fibromyalgia impact, physical function, fatigue, pain catastrophizing, kinesiophobia, and positive–negative affect were recorded at baseline, and at weeks 12 and 24 of the intervention. ResultsAt the end of 12 weeks, the sleep quality improved significantly in the CST group (P = 0.037) and Bowen therapy group (P = 0.023), and the PPT improved significantly in the Bowen therapy group (P = 0.002) and the standard exercise group (P < 0.001), compared to the static touch group. These improvements were maintained at 24 weeks. No between-group differences were observed for other secondary outcomes. ConclusionCST and Bowen therapy improved sleep quality, and Bowen therapy and standard exercises improved pain threshold in the short term. These improvements were retained within the groups in the long term by adding exercises. CST and Bowen therapy are treatment options to improve sleep and reduce pain in FMS. Trial registration numberRegistered at Clinical Trials Registry of India with the number of CTRI/2020/04/024551.Please cite this article as: Ughreja RA, Venkatesan P, Gopalakrishna DB, Singh YP, Lakshmi VR. Effectiveness of craniosacral therapy, Bowen therapy, static touch and standard exercise program on sleep quality in fibromyalgia syndrome: a randomized controlled trial. J Integr Med. 2024; 22(4): 474–484.

Effectiveness of Craniosacral therapy, Bowen therapy, static touch, and standard exercise program on sleep quality in fibromyalgia syndrome: A protocol for a randomized controlled trial

Effectiveness of Craniosacral therapy, Bowen therapy, static touch, and standard exercise program on sleep quality in fibromyalgia syndrome: A protocol for a randomized controlled trial

Hold me or stroke me? Individual differences in static and dynamic affective touch.

Low-threshold mechanosensory C-fibres, C-tactile afferents (CTs), respond optimally to sensations associated with a human caress. Additionally, CT-stimulation activates brain regions associated with processing affective states. This evidence has led to the social touch hypothesis, that CTs have a key role in encoding the affective properties of social touch. Thus, to date, the affective touch literature has focussed on gentle stroking touch. However, social touch interactions involve many touch types, including static, higher force touch such as hugging and holding. This study aimed to broaden our understanding of the social touch hypothesis by investigating relative preference for static vs dynamic touch and the influence of force on these preferences. Additionally, as recent literature has highlighted individual differences in CT-touch sensitivity, this study investigated the influence of affective touch experiences and attitudes, autistic traits, depressive symptomology and perceived stress on CT-touch sensitivity. Directly experienced, robotic touch responses were obtained through a lab-based study and vicarious touch responses through an online study where participants rated affective touch videos. Individual differences were determined by self-report questionnaire measures. In general, static touch was preferred over CT-non-optimal stroking touch, however, consistent with previous reports, CT-optimal stroking (velocity 1-10 cm/s) was rated most pleasant. However, static and CT-optimal vicarious touch were rated comparably for dorsal hand touch. For all velocities, 0.4N was preferred over 0.05N and 1.5N robotic touch. Participant dynamic touch quadratic terms were calculated for robotic and vicarious touch as a proxy CT-sensitivity measure. Attitudes to intimate touch significantly predict robotic and vicarious quadratic terms, as well as vicarious static dorsal hand touch ratings. Perceived stress negatively predicted robotic static touch ratings. This study has identified individual difference predictors of CT-touch sensitivity. Additionally, it has highlighted the context dependence of affective touch responses and the need to consider static, as well as dynamic affective touch.

Effects of temperature and water content on wet perception during the static touch of moist paper

[Background] Wet perception plays an essential role in behavioral thermoregulation. It has been suggested that mechanical and thermal stimuli affect wet perception; however, the mechanism remains unclear. This study aimed to clarify the effects of water content and temperature on the wet perception of moist papers. [Methods] Twenty-seven healthy volunteers (14 males and 13 females, age 25 ± 5 years) participated in this study, which comprised two experimental trials. In Experiment 1, participants placed the index finger on 2 x 2 cm filter paper of 6 different water content (0.00, 3.75, 7.50, 11.25, 15.00, or 18.75 μg/cm 2 ) for 15 s, of which temperature was controlled at 30ºC with Peltier apparatus. During the last 5 s of the stimulation period, participants were asked to report if they had wet perception or not. Each water content was presented five times, and the percentage rate of wet perception was calculated. In Experiment 2, participants placed the index finger on 2 x 2 cm filter paper of water content of 18.75 μg/cm 2 for 15 s, of which temperature was controlled at either 20, 25, 30, 35, or 40°C with Peltier apparatus. During the last 5 s of the stimulation period, participants were asked to report the intensity of their thermal and wet sensations with a visual analog scale. Each temperature was presented five times. [Results] Experiment 1: The percentage rates of wet perception of 3.75, 7.50, 11.25, 15.00, and 18.75 μg/cm 2 were significantly higher than that of 0.00 μg/cm 2 ( p &lt; 0.05). The percentage rates of wet perception of 11.25, 15.00, and 18.75 μg/cm 2 were significantly greater than those of 3.75 μg/cm 2 ( p &lt; 0.01) and 7.5 μg/cm 2 ( p &lt; 0.005). Experiment 2: Thermal sensation of the stimuli of 25, 30, 35, and 40ºC was greater than that of the 20ºC stimulus ( p &lt; 0.001). Wet perception of the stimulus of 20ºC was greater than that of 25, 30, 35, and 40ºC. Wet perception of the stimulus of 25ºC was higher than those of 30, 35, and 40ºC ( p &lt; 0.05). [Discussion and Conclusions] The percentage rate of wet perception increased with the water content of the paper. Thus, participants could discriminate such small differences in the water content. The wet perception was augmented by stimulus temperature lower than 30ºC, while stimulus temperature above 30ºC did not show a clear relationship with the intensity of wet perception. The cold sensation may play an important role in modulating wet perception. Research Fellow of Japan Society for the Promotion of Science and Japan Society for the Promotion of Science KAKENHI Grant-in-Aid for Scientific Research A 19H01128. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Dynamic touch induces autonomic changes in preterm infants as measured by changes in heart rate variability

Preterm birth significantly increases the risk of developing various long-term health problems and developmental disabilities. While touch is a crucial component of many perinatal care strategies, the neurobiological underpinnings are rarely considered. C-tactile fibers (CTs) are unmyelinated nerve fibers that are activated by low-force, dynamic touch. Touch directed specifically at CTs activates the posterior insular cortex, consistent with an interoceptive function, and has been shown to reduce heart rate and increase oxygen saturation. The current research compared the effect of five minutes of CT optimal velocity stroking touch versus five minutes of static touch on autonomic markers of preterm infants between 28 and 37 weeks gestational age. CT touch induces a higher increase in heart rate variability metrics related to the parasympathetic system, which persisted for a 5-minute post-touch period. Conversely, there was no such increase in infants receiving static touch. The present findings confirmed that CTs signal the affective quality of nurturing touch, thereby arguing an additional neurobiological substrate for the evident valuable impacts of neonatal tactile interventions and improving the effectiveness of such interventions.

Characteristics of wet perception during the static touch of moist paper by the index fingertip alongside thermal stimulus application

Several factors have been reported to affect the perception of wetness. In the present study, we aimed to examine how wet perception changes when the factors related to thermal and/or wetness stimuli are modulated. First, the percentage of participants experiencing wet perception among filter papers with different water contents (0.00, 3.75, 7.50, 11.25, 15.00, and 18.75 µg/cm2, corresponding to 0.00, 0.18, 0.37, 0.55,0.73 and 0.91 µg/mm3) was evaluated during static touch by the right index finger pad. The stimulus temperature was maintained at 30 °C. Second, the wet perception of paper with a water content of 18.75 µg/cm2 was evaluated at stimulus temperature of 20 °C, 25 °C, 30 °C, 35 °C, and 40 °C. In the first experiment, the percentage of participants experiencing wet perception elevated with the increasing water content; however, the percentage plateaued at 11.25 µg/cm2 of water (68.1 ± 25.5%). In the second experiment, when the stimulus temperature was < 30 °C, the wet perception increased as the stimulation temperature decreased. However, the wet perception reached a plateau at a stimulation temperature ≥30 °C. Participants experienced wet perception more consistently as the water content increased when the stimulus temperature was 30 ˚C. The effect of temperature on wet perception was limited to the stimulus temperature of <30 °C at which cold sensation was induced. However, no clear relationship between stimulus temperature and wet perception was observed when the stimulus temperature was ≥30 ˚C at which warm/hot sensation was induced.

Electromechanical model for object roughness perception during finger sliding

Touch allows us to gather abundant information in the world around us. However, how sensory cells embedded in the fingers convey texture information into their firing patterns is still poorly understood. Here, we develop an electromechanical model for roughness perception by incorporating main ingredients such as voltage-gated ion channels, active ion pumps, mechanosensitive channels, and cell deformation. The model reveals that sensory cells can convey texture wavelengths into the period of their firing patterns as the finger slides across object surfaces, but they can only convey a limited range of texture wavelengths. We also show that an increase in sliding speed broadens the decoding wavelength range at the cost of reduction of lower perception limits. Thus, a smaller sliding speed and a bigger contact force may be needed to successfully discern a smooth surface, consistent with previous psychophysical observations. Moreover, we show that cells with slowly adapting mechanosensitive channels can still fire action potentials under static loadings, indicating that slowly adapting mechanosensitive channels may contribute to the perception of coarse textures under static touch. Our work thus provides a new theoretical framework to study roughness perception and may have important implications for the design of electronic skin, artificial touch, and haptic interfaces.

Newborns' clinical conditions are correlated with the neonatal assessment manual scorE (NAME).

ObjectiveTo investigate the relationship between the Neonatal Assessment Manual scorE (NAME) and newborns' clinical condition on a large number of infants. The NAME model was developed as an instrument to assess the infant's general conditions, especially in NICUs, by evaluating how the infant's body responds to an external stressor such as static touch. Previous studies, employing experienced assessors, showed good validity indices as well as high inter-rater reliability.Study designNewborns were recruited at the “Vittore Buzzi” Pediatric Hospital NICU ward in Milan and their clinical conditions were collected through a standardized form—the complexity index. Two manual practitioners assessed all eligible newborns using the NAME scores. Data was analyzed using Kendall's τ correlation and odds ratio (OR) to assess the relationship between the NAME scores and the complexity index.ResultsTwo hundred two newborns (46% female; 34.1 w ± 4.3; birth weight of 2,093.4 gr ± 879.8) entered the study. The Kendall's correlation between the clinical conditions (complexity index) and the NAME score was −0.206 [95% CI: (−0.292, −0.116), p-value < 0.001], corresponding to an OR of 0.838 [95% CI: (0.757, 0.924), p-value < 0.001]. Further exploratory analyses showed significant correlation between gestational age, birth weight and NAME scores.ConclusionThe present paper adds evidence to the NAME model validity by demonstrating its applicability in the clinical neonatological context.

Meis1 Regulates Nociceptor Development and Behavioral Response to Tactile Stimuli.

Nociceptors in the dorsal root ganglia (DRG) and trigeminal ganglia (TG) are necessary for transmitting pain and itch signals. However, the molecular mechanism regulating nociceptor development remains largely unknown. This study identifies that the transcription factor Meis1 is generally expressed in two groups of sensory neurons in the developing DRG. During prenatal and neonatal stages, approximately 2/3 of Meis1+ neurons are Runx1+ nociceptors, while 1/3 of Meis1+ neurons are NF200+ myelinated neurons. At postnatal stages, Meis1 expression in nociceptors is gradually reduced. Here, we constructed a Meis1 conditional knockout mouse line to selectively delete Meis1 in Nav1.8 lineage nociceptors. Microarray analyses showed that differentially expressed genes in the Meis1 mutant DRG were enriched in pathways related to sensory perception of pain and nervous system development. In addition, Meis1 regulates the expression of some marker genes of Nppb+ neurons and C-LTMRs. Furthermore, Meis1 mutant mice exhibit behavioral deficits in response to light mechanical pain, static touch and chemical itch. Therefore, this study reveals that Meis1 is required to regulate the development of nociceptors.

Osteopathic Manipulative Treatment Regulates Autonomic Markers in Preterm Infants: A Randomized Clinical Trial.

Osteopathic manipulative treatment (OMT) has been found to be effective in the context of premature infants. Nonetheless, no studies have investigated the immediate effects of OMT on heart rate variability (HRV). As altered HRV reflects poor or worsening newborn’s clinical conditions and neurodevelopment, should OMT improve HRV fluctuations, it could become a relevant intervention for improving the care of preterm newborns. Therefore, this study aimed to evaluate whether OMT could affect HRV. The study was carried out at the Buzzi Hospital in Milan. From the neonatal intensive care unit, ninety-six preterm infants (41 males) were enrolled and were randomly assigned to one of two treatment groups: OMT or Static Touch. The infants were born at 33.5 weeks (±4.3) and had a mean birth weight of 2067 g (±929). The study had as primary outcome the change in the beat-to-beat variance in heart rate measured through root mean square of consecutive RR interval differences (RMSSD); other metrics were used as secondary and exploratory analyses. Despite the lack of statistically significant results regarding the primary outcomeand some study limitations, compared to static touch, OMT seemed to favor a parasympathetic modulation and improved HRV, which could reflect improvement in newborn’s clinical conditions and development.

The role of maternal touch in the association between SLC6A4 methylation and stress response in very preterm infants.

Very preterm (VPT) infants requiring hospitalization in the Neonatal Intensive Care Unit (NICU) are exposed to several stressful procedural experiences. One consequence of NICU-related stress is a birth-to-discharge increased serotonin transporter gene (SLC6A4) methylation that has been associated with poorer stress regulation at 3 months of age. Maternal touch is thought to support infants' stress response, but its role in moderating the effects of SLC6A4 methylation changes is unknown. The aim of this study was to assess the role of maternal touch in moderating the association between increased SLC6A4 methylation and stress response in 3-month-old VPT infants. Twenty-nine dyads were enrolled and at 3 months (age corrected for prematurity), participated in the Face-to-Face Still-Face paradigm to measure infants' stress response (i.e., negative emotionality) and the amount of maternal touch (i.e., dynamic and static). Results showed that low level of maternal touch is associated with high level of negative emotionality during social stress. Furthermore, during NICU stay SLC6A4 methylation in VPT exposed to low level of maternal touch at 3 months was associated with increased negative emotionality. Thus, low levels of maternal static touch can intensify the negative effects of SLC6A4 epigenetic changes on stress response in 3-month-old VPT infants.

Impact of seabed slope on steel catenary riser touchdown zone response

Several factors can affect the response of steel catenary risers (SCR) around its touch down zone (TDZ). These include the stiffness of the soil, the soil suction force on the riser TDZ, the soil degradation with cyclic TDZ loading, etc. Riser strength and fatigue response computation are usually performed considering flat seabed and with the use of rigid or linear (spring) riser soil interaction model. However, bathymetric information obtained for the SCR lay path on the seabed reveal complex seabed profile variation, indicating that the seabed is far from being flat around the SCR TDZ. This paper presents findings from an investigation conducted on the influence of seabed slopes on the strength and fatigue response of SCRs, using a non-linear (NL) riser soil interaction model. The responses of SCRs on positively and negatively sloped seabed (rotated about the static touch down point on flat seabed) are compared with responses of SCRs on flat seabed. From the results, it can be deduced that the SCR dynamic and fatigue responses may be overpredicted or underpredicted in magnitudes dependent on the slope deviation of actual seabed from a flat seabed.

EFETIVIDADE DO TRATAMENTO MANIPULATIVO OSTEOPÁTICO NOS SINAIS VITAIS, EM NEONATOS COM DISFUNÇÃO DE SUTURA CRANIANA

O Tratamento Manipulativo Osteopático (TMO) foi testado com sucesso no contexto de neonatos a termo saudáveis. No presente estudo foram monitorados os efeitos da TMO sobre a Frequência Cardíaca (FC), Saturação de Oxigênio (SpO2) e Frequência Respiratória (FR); imediatamente após o tratamento e após 10 minutos e 24 horas. O objetivo do presente estudo foi avaliar a efetividade do tratamento manipulativo osteopático nos valores da FC, SpO2 e FR e comparar com o efeito do toque estático. Materiais e Métodos: a pesquisa trata-se de um ensaio clínico aleatório de acordo com as regras do Consort-Statement, a amostra foi composta por 46 neonatos, recrutados no Hospital Universitário do Oeste do Paraná no ano de 2020; os participantes do estudo foram alocados aleatoriamente em dois grupos: Toque estático (G1) e Tratamento Manipulativo Osteopática (G2); a intervenção foi realizada em um único procedimento. Resultados: houve significância estatística no pós intervenção imediata, para a redução da FC para os dois grupos e para o G2 também foram identificados aumento da SpO2 e redução da FR na avaliação de 10 minutos e 24 horas pós intervenção. Portanto, conclui-se que para neonatos, uma única intervenção osteopática pode induzir a alterações benéficas sobre os sinas vitais.

No need to touch this: Bimanual haptic slant adaptation does not require touch.

In our daily life, we often interact with objects using both hands raising the question the question to what extent information between the hands is shared. It has, for instance, been shown that curvature adaptation aftereffects can transfer from the adapted hand to the non-adapted hand. However, this transfer only occurred for dynamic exploration, e.g. by moving a single finger over a surface, but not for static exploration when keeping static contact with the surface and combining the information from different parts of the hand. This raises the question to what extent adaptation to object shape is shared between the hands when both hands are used in static fashion simultaneously and the object shape estimates require information from both hands. Here we addressed this question in three experiments using a slant adaptation paradigm. In Experiment 1 we investigated whether an aftereffect of static bimanual adaptation occurs at all and whether it transfers to conditions in which one hand was moving. In Experiment 2 participants adapted either to a felt slanted surface or simply be holding their hands in mid-air at similar positions, to investigate to what extent the effects of static bimanual adaptation are posture-based rather than object based. Experiment 3 further explored the idea that bimanual adaptation is largely posture based. We found that bimanual adaptation using static touch did lead to aftereffects when using the same static exploration mode for testing. However, the aftereffect did not transfer to any exploration mode that included a dynamic component. Moreover, we found similar aftereffects both with and without a haptic surface. Thus, we conclude that static bimanual adaptation is of proprioceptive nature and does not occur at the level at which the object is represented.

Effects of osteopathic treatment versus static touch on heart rate and oxygen saturation in premature babies: A randomized controlled trial

BackgroundOsteopathic manipulative treatment (OMT) has been successfully tested in the context of preterm infants. No studies, however, have been conducted to investigate the OMT immediate effects on physiological measurements, such as partial oxygen saturation (SpO2) and heart rate (HR). The purpose of the present study was to assess the effect of osteopathic treatment on SpO2 and HR values and to compare it with 10 min of static touch. Materials and methodsNinety-six preterm infants (41 male), aged 33.5 weeks (±4.3) with mean weight at birth of 2067gr (±929) were recruited from the neonatal intensive care unit (NICU) of the Buzzi Hospital in Milan, and randomly allocated to two groups: OMT and Static Touch. Each protocol session consisted of: a) 5-min Pre-touch baseline recording, b) 10-min touch procedure, c) 5-min post-touch recording. Primary and secondary outcomes were, respectively, the baseline changes of HR and SpO2. ResultsThe 2 × 2 repeated measure ANOVA for HR showed a statistically significant effect (F (1,94) = 5.34; p < 0.02), revealing that the OMT group decreases the HR value at T2 (p = 0.006). In contrast, SpO2 analysis showed an increase of SpO2 value where the OMT group demonstrated higher values at T2 (p = 0.04). ConclusionResults from the present study suggest that a single osteopathic intervention may induce beneficial effects on preterm physiological parameters. Trial registrationClinicalTrials.gov identifier: NCT03833635 – Date: February 7, 2019.

Haptic discrimination of 3D-printed patterns based on natural visual textures

We perceive spatial textures mainly through eyes and hands. In contrast to visual texture perception, computational mechanisms of haptic texture perception remain poorly understood. Here we measured haptic texture discrimination ability of 3D printed surfaces transcribed by visual images of five natural textures (stones, leaves etc.). For each texture image, the intensity map was converted into the 3D surface height modulation of a 40×40mm plate. The textures look sufficiently different and the maximum modulation depth (2mm) was well above the haptic detection threshold. Nevertheless, observers (n=10) could not accurately discriminate some texture pairs. In the main experiment, the observer passively touched the plate swept on their stabilized index finger (passive scan mode), but even when we tested other touching modes, the performance was improved only slightly (active scan), or not at all (static touch, vibration only). Since the amplitude spectra of natural visual textures are similar to each other (fall by a factor of f-a), we hypothesized that haptic texture discrimination may rely solely on the difference in amplitude spectra, or on the spatial-frequency/orientation subband histograms. In agreement with this, the discrimination performance we obtained could be explained by a multivariate linear regression based on the amplitude difference between the paired textures. In an additional experiment, we directly tested this hypothesis by matching the subband histogram of each texture using a texture synthesis algorithm (Heeger & Bergen, 1995). Haptic discrimination of these textures was found to be nearly impossible, although visual discrimination remains feasible due to differences in higher-order statistics (joint subband statistics to which V2 neurons are sensitive, or more complex phase information detectable by attentive foveal vision). These findings suggest that haptic texture processing may be qualitatively different from visual texture processing in that it simply relies on lower-order image statistics.

Dynamic touch reduces physiological arousal in preterm infants: A role for c-tactile afferents?

Preterm birth is a significant risk factor for a range of long-term health problems and developmental disabilities. Though touch plays a central role in many perinatal care strategies, the neurobiological basis of these approaches is seldom considered. C-Tactile afferents (CTs) are a class of unmyelinated nerve fibre activated by low force, dynamic touch. Consistent with an interoceptive function, touch specifically targeted to activate CTs activates posterior insular cortex and has been reported to reduce autonomic arousal. The present study compared the effect of 5 min of CT optimal velocity stroking touch to 5 min of static touch on the heart-rate and oxygen saturation levels of preterm infants between 28- & 37-weeks gestational age. CT touch produced a significant decrease in infants’ heart-rates and increase in their blood oxygenation levels, which sustained throughout a 5-min post-touch period. In contrast, there was no significant change in heart-rate or blood oxygenation levels of infants receiving static touch. These findings provide support for the hypothesis that CTs signal the affective quality of nurturing touch, providing a neurobiological substrate for the apparent beneficial effects of neonatal tactile interventions and offering insight for their optimisation.

Long Term Cosmetic Application Improves Tactile Discrimination in the Elderly; a New Psychophysical Approach.

Introduction: Tactile sensitivity is impaired in older adults, which contributes to the loss of manual dexterity and mobility function. The reliability of classical psychophysical tests, such as two-point gap discrimination, has been questioned. Here we tested a new method to determine tactile acuity during dynamic touch, which is more functional than static touch. The aim was to validate a method providing a high level of discrimination of tactile acuity in the elderly.Methods: We tested the ability of subjects to evaluate the distance between bands printed on poly-methyl-methacrylate (PMMA) sheets. Pairs of sheets were compared in two groups of participants aged from 60 to 74 years; the test group was required to apply a cosmetic foam with an active ingredient on both their hands twice a day for 1 month, the control group had an identical task but used the same cosmetic foam without any active ingredient. The tests were run in a double-blind, placebo-controlled study.Results: The tactile discrimination threshold decreased by 83 μm after 1 month of cosmetic application in the group using the active ingredient, while it was unchanged in the control group.Discussion: The test presented here provided highly accurate results and should be useful to determine tactile performance. It allows the monitoring of tactile rehabilitation and/or skin treatments used to restore tactile acuity in the elderly.