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1.
Brain Sci ; 14(8)2024 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-39199444

RESUMEN

The purpose of the present study was to examine whether spatial or temporal prediction of the tactile stimulus contributes to tactile sensitivity. To investigate the effect of spatial prediction on tactile sensitivity, electrical stimuli were provided for the digit nerve in one of five fingers, and advanced notice of the stimulating finger was provided before the stimulus in some trials but not in others. There was no significant effect of spatial prediction on the intensity at the perceptual threshold of the digit nerve stimulus. This indicates that spatial prediction of the tactile stimulus does not influence tactile sensitivity. To examine the effect of temporal prediction, an auditory warning cue was provided 0, 1, or 10 s before the electrical stimulus to the digit nerve. The stimulus intensity at the perceptual threshold in the trials with the 1 s warning cue was lower than those with the 0 s warning cue. This indicates that temporal prediction enhances tactile sensitivity. The stimulus intensity at the perceptual threshold in the trials with the 1 s warning cue was lower than those with the 10 s warning cue. This means that the contribution of temporal prediction to the tactile sensitivity is greater as the warning cue is closer to the time of the stimulus. This finding may be explained by a defense mechanism activated when humans predict that a tactile stimulus is coming soon.

2.
Sci Rep ; 14(1): 17836, 2024 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-39090148

RESUMEN

The capacity to perceive tactile input at the fingertips, referred to as tactile sensitivity, is known to diminish with age due to regressive changes to mechanoreceptor density and morphology. Sensitivity is measured as perceptual responses to stimuli of varying intensity. Contrary to traditional sensitivity monitoring instruments, smartphones are uniquely suited for remote assessment and have shown to deliver highly calibrated stimuli along a broad spectrum of intensity, which may improve test reliability. The aim of this study was to evaluate a vibration-emitting smartphone application, the Vibratus App, as a mode of estimating tactile sensory thresholds in the aging adult. The peripheral nerve function of 40 neurologically healthy volunteers (ages 18-71) was measured using monofilaments, a 128-Hz tuning fork, the Vibratus App, and nerve conduction studies (NCS). Between group differences were analyzed to determine each measurement's sensitivity to age. Spearman correlation coefficients depicted the associative strength between hand-held measurements and sensory nerve action potential (SNAP) amplitude. Inter-rater reliability of traditional instruments and the software-operated smartphone were assessed by intraclass correlation coefficient (ICC2,k). Measurements taken with Vibratus App were significantly different between age groups (p < 0.001). The inter-rater reliability of monofilament, smartphone vibration, and tuning fork testing was moderate to good (ICC2,k = 0.65, 0.69, and 0.79, respectively). The findings of this study support further investigation of smartphones as sensitivity monitoring devices for at home monitoring of skin sensitivity.


Asunto(s)
Envejecimiento , Umbral Sensorial , Teléfono Inteligente , Vibración , Humanos , Adulto , Persona de Mediana Edad , Anciano , Masculino , Femenino , Adulto Joven , Adolescente , Umbral Sensorial/fisiología , Envejecimiento/fisiología , Tacto/fisiología , Piel , Aplicaciones Móviles , Reproducibilidad de los Resultados
3.
BMC Psychiatry ; 24(1): 558, 2024 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-39138461

RESUMEN

BACKGROUND: Tactile sensitivity and sensory overload in ADHD are well-documented in clinical-, self-, and parent- reports, but empirical evidence is scarce and ambiguous and focuses primarily on children. Here, we compare both empirical and self-report tactile sensitivity and ADHD symptomatology in adults with ADHD and neurotypical controls. We evaluate whether tactile sensitivity and integration is more prevalent in ADHD and whether it is related to ADHD symptom severity. METHODS: Somatosensory evoked potential (SEP) amplitudes were measured in 27 adults with ADHD and 24 controls during four conditions (rest, stroking of the own arm, stroking of the arm by a researcher, and stroking of an object). Participants also filled out questionnaires on tactile sensitivity and ADHD symptoms and performed a Qb-test as an objective measure of ADHD symptom severity. RESULTS: Participants with ADHD self-reported greater tactile sensitivity and ADHD symptom severity than controls and received higher scores on the Qb-test. These values correlated with one another. ADHD participants showed lower tolerable threshold for electrical radial nerve stimulus, and greater reduction in cortical SEP amplitudes during additional tactile stimuli which was correlated with ADHD symptoms. CONCLUSIONS: We find that ADHD symptomatology and touch sensitivity are directly linked, using both self-reports and experimental measures. We also find evidence of tactile sensory overload in ADHD, and an indication that this is linked to inattention specifically. Tactile sensitivity and sensory overload impact the functioning and life quality of many people with ADHD, and clinicians should consider this when treating their patients.


Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad , Potenciales Evocados Somatosensoriales , Humanos , Trastorno por Déficit de Atención con Hiperactividad/fisiopatología , Masculino , Femenino , Potenciales Evocados Somatosensoriales/fisiología , Adulto , Percepción del Tacto/fisiología , Tacto/fisiología , Autoinforme , Índice de Severidad de la Enfermedad , Adulto Joven
4.
Front Aging Neurosci ; 16: 1387136, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39015473

RESUMEN

Touch sensitivity generally declines with age, contributing to loss of manual dexterity and tactile function. We investigated how touch changes over the lifespan, using different tests and on three body sites. We used a classical test of force detection sensitivity, where calibrated monofilaments were applied passively to the right index finger pad, forearm, and cheek. In addition, at the index, we used an active touch spatial discrimination task, developed by our group. Spatial discrimination was estimated through participants' ability to evaluate the distance between parallel bands printed on acrylic plates. Data were collected from 96 healthy women, aged 20-75 years. Force detection and tactile spatial discrimination on the index deteriorated significantly with age; however, no change was found for tactile detection on the forearm or cheek. Tactile detection on the cheek remained remarkably highly sensitive throughout life. There was a significant positive relationship between force detection and spatial discrimination on the index. Further, force detection on the forearm was significantly associated with detection on the index and cheek. Our results suggest a decrease in touch perception with age on the index finger pad, yet a preservation of tactile sensitivity in hairy skin. This opens discussion about the impact of daily activities upon the glabrous hand skin and on the function of hairs in tactile sensitivity. We highlight the need for new methods in evaluating tactile sensitivity on hairy skin.

5.
Front Vet Sci ; 11: 1401130, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38962701

RESUMEN

Introduction: Surgical glove use may be associated with a decrease in tactile sensitivity, with thicker gloves or double-gloving techniques further altering sensation. This study evaluates digital tactile sensitivity by use of a Grating Orientation Task (GOT) with multiple sterile gloving techniques (no gloves, single standard gloving, double standard gloving, orthopedic gloves, and micro-thickness gloves). Methods: Each participant performed the GOT at increasing grating widths until correctly noting orientation in ≥8 of 10 trials with multiple glove types or double-gloving technique. Glove order was randomly assigned and participants were blinded to the orientation and dome size. Results: All gloves except micro-thickness gloves showed increased threshold sensitivity values (i.e. worse fingertip sensitivity) when compared to control (micro:control, p = 0.105, others:control, p < 0.05). Single-layer gloves showed no significant difference in sensitivity when compared to orthopedic (p = 0.06) or double-layer latex gloves (p = 0.26). Discussion: Standard latex gloves decreased fingertip sensitivity when evaluated with the GOT. Double-layer and orthopedic latex gloves do not decrease sensitivity when compared with single-layer gloving. Micro-thickness gloves may provide similar tactile sensitivity to no surgical glove.

6.
Int J Occup Saf Ergon ; 30(3): 845-857, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38872424

RESUMEN

The hands are the most complex organs of the body for performing various activities. Therefore, it is critical to protect them against dangers. Protective gloves can reduce or prevent injuries, but they can downgrade hand performance in various aspects, including tactile sensitivity, strength, grip force and hand dexterity. In this study, eight protective gloves with different designs and materials were made. The study investigated the influence of the number of layers and several characteristics, e.g., mass per square meter, thickness, bending stiffness and compressibility, on the gloved hand performance regarding protection ability, tactile sensitivity, strength capability and manual dexterity. The results indicated that despite the improving effects of increasing layer thickness, weight, bending energy and compressibility on protection ability, the gloves diminish tactile sensitivity, grip and pinch force, and manual dexterity. Therefore, it is necessary to select an optimum design to ensure a satisfactory trade-off between protection and performance.


Asunto(s)
Guantes Protectores , Fuerza de la Mano , Mano , Humanos , Fuerza de la Mano/fisiología , Mano/fisiología , Ensayo de Materiales , Diseño de Equipo , Tacto/fisiología , Masculino , Adulto
7.
J Neurochem ; 2024 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-38837765

RESUMEN

Altered sensory processing is a common feature in autism spectrum disorder (ASD), as recognized in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). Although altered responses to tactile stimuli are observed in over 60% of individuals with ASD, the neurobiological basis of this phenomenon is poorly understood. ASD has a strong genetic component and genetic mouse models can provide valuable insights into the mechanisms underlying tactile abnormalities in ASD. This review critically addresses recent findings regarding tactile processing deficits found in mouse models of ASD, with a focus on behavioral, anatomical, and functional alterations. Particular attention was given to cellular and circuit-level functional alterations, both in the peripheral and central nervous systems, with the objective of highlighting possible convergence mechanisms across models. By elucidating the impact of mutations in ASD candidate genes on somatosensory circuits and correlating them with behavioral phenotypes, this review significantly advances our understanding of tactile deficits in ASD. Such insights not only broaden our comprehension but also pave the way for future therapeutic interventions.

8.
Chem Senses ; 492024 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-38526180

RESUMEN

Oral tactile sensitivity underpins food texture perception, but few studies have investigated mechanoreception in oral tissues. During food consumption, oral tissues are exposed to a wide range of temperatures and chemical entities. The objective of the present study was to assess the influence of thermal sensations on lingual roughness sensitivity. Just-noticeable difference thresholds (JNDs) were determined using the staircase method for surface roughness from stainless steel coupons (Ra; 0.177-0.465 µm). Thresholds were assessed when cooling or heating the metal stimuli (n = 32 subjects). Compared to the JND threshold obtained at an ambient stimulus temperature (21 °C: 0.055 ±â€…0.010 µm), a cold (8 °C) temperature significantly (P = 0.019) reduced tongue sensitivity (i.e. increased JND) to surface roughness (0.109 ±â€…0.016 µm, respectively) whereas warm and hot temperatures had no significant effect (35 °C: 0.084 ±â€…0.012 µm; 45 °C: 0.081 ±â€…0.011 µm). To assess whether the effect of cooling on roughness thresholds is TRPM8-dependent, we collected roughness thresholds in a second cohort of subjects (n = 27) following the lingual application of the cooling compound Evercool 190 (24.3 µM). Interestingly, when Evercool 190 was used to elicit the cold sensation, lingual roughness JNDs were unaffected compared to the control application of water (EC: 0.112 ±â€…0.016 µm; water: 0.102 ±â€…0.017 µm; P = 0.604). That lingual roughness sensitivity is decreased by cold temperature, but not chemicals evoking cold sensations, suggests the mechanism underpinning thermal modulation is not TRPM8 dependent.


Asunto(s)
Frío , Calor , Humanos , Temperatura , Tacto , Agua
9.
J Cosmet Dermatol ; 23(1): 296-307, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37522513

RESUMEN

BACKGROUND: Tactile sensation plays a crucial role in object manipulation, communication, and even emotional well-being. It has been reported that the deformability of skin (also described as skin compliance) that shows a large mechanical response to stimuli is associated with high tactile sensitivity. However, although the compliance of the stratum corneum, the outermost layer of skin, can change daily due to skin care and environmental factors, few studies have quantified the effect of the stratum corneum on tactile sensation. AIMS: We investigated the changes in tactile sensitivity resulting from skin hydration and identified corresponding alterations in the compliance of the stratum corneum. METHODS: A randomized controlled trial was conducted. Participants were randomly assigned to an intervention group (n = 20) that had a moisturizing cream applied to their cheeks or a control group (n = 19) that had Milli-Q water applied to their cheeks. Tactile discrimination performance was assessed using psychophysical techniques before and after application. The water content, mechanical response characteristics, and penetration of PEG/PPG-17/4 dimethyl ether from the cream in the stratum corneum were evaluated to identify hydration effects. Skin deformations occurring during tactile sensation were measured concurrently using a suction device employed for tactile stimulation. RESULTS: Tactile sensitivity was increased in participants who had cream applied to the skin surface, while no significant change was observed in participants who received Milli-Q water. The improved discrimination of tactile stimulus intensity was directly related to the magnitude of skin displacement. The higher water content of the stratum corneum due to cream application decreased the dynamic modulus of elasticity of the stratum corneum and increased the skin's extensibility in response to tactile stimuli. CONCLUSIONS: Hydrating the stratum corneum significantly enhances tactile sensitivity and is accompanied by an increase in skin extensibility, a factor in tactile intensity perception. The compliance of the thin stratum corneum layer plays a crucial role in tactile experiences that involve skin stretching.


Asunto(s)
Epidermis , Piel , Humanos , Agua/farmacología , Elasticidad , Cuidados de la Piel , Ensayos Clínicos Controlados Aleatorios como Asunto
10.
EBioMedicine ; 99: 104896, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38041920

RESUMEN

BACKGROUND: Sensory impairment has been related to age-associated cognitive decline. While these associations were investigated primarily in the auditory and visual domain, other senses such as touch have rarely been studied. Thus, it remains open whether these results are specific for particular sensory domains, or rather point to a fundamental role of sensory deficits in cognitive decline. METHODS: Data from 31 participants with mild cognitive impairment (MCI), 46 participants with frailty, and 23 non-clinical control participants (NCCs) were included. We assessed sensory function using visual acuity and contrast sensitivity, hearing threshold, and mechanical detection threshold. Cognitive function in participants with MCI was assessed using associative memory performance. Group differences on sensory thresholds were tested using analyses of covariance with age, sex, and years of education as covariates. Associations between measures within participants with MCI were evaluated using Spearman correlations. FINDINGS: We found a significant difference in mechanical detection threshold between the groups (p < 0.001, η2 = 0.18). Participants with MCI showed significantly reduced tactile sensitivity compared to participants with frailty and NCCs. In participants with MCI, lower associative memory performance was significantly related to reduced tactile sensitivity (rs = 0.39, p = 0.031) and auditory acuity (rs = 0.41, p = 0.022). INTERPRETATION: Our results indicate that reduced tactile sensitivity is related to cognitive decline. Prospective studies should investigate the age-related alterations of multimodal sensory processes and their contribution to dementia-related processes. FUNDING: Deutsche Forschungsgemeinschaft (FL 156/41-1) and a grant of the Hector-Stiftung II, Weinheim, Germany.


Asunto(s)
Disfunción Cognitiva , Fragilidad , Humanos , Tacto , Estudios Prospectivos , Disfunción Cognitiva/complicaciones , Cognición , Pruebas Neuropsicológicas
11.
Support Care Cancer ; 31(12): 627, 2023 Oct 13.
Artículo en Inglés | MEDLINE | ID: mdl-37828382

RESUMEN

PURPOSE: Patients with head and neck cancer (HNC) are at high risk of malnutrition due to eating difficulties partly mediated by sensory alterations and salivary dysfunction. Clinical studies have mostly focused on taste and smell alterations, while changes in oral somatosensory perception are largely understudied. The study aimed to investigate oral somatosensory (tactile, texture, chemesthetic, and thermal) responses and salivary functions of HNC patients in comparison to healthy controls. METHODS: A cross-sectional study was conducted using psychophysical tests in HNC patients (n = 30) and in age- and gender-matched control subjects (n = 30). The tests included measurements of point-pressure tactile sensitivity, whole-mouth chemesthetic stimulation, food texture discrimination, and temperature discrimination. Salivary functions, including hydration, saliva consistency, pH, volume, and buffering capacity, were also evaluated. RESULTS: HNC patients demonstrated significantly lower chemesthetic sensitivity (for medium and high concentrations, p < 0.05), thermal sensitivity (p = 0.038), and salivary functions (p = 0.001). There were indications of lower tactile sensitivity in the patient group (p = 0.101). Patients were also less sensitive to differences in food roughness (p = 0.003) and firmness (p = 0.025). CONCLUSION: This study provided evidence that sensory alterations in HNC patients extend beyond their taste and smell. The measurements demonstrated lower somatosensory responses, in part associated with their reduced salivary function. Oral somatosensory alterations and salivary dysfunction may consequently impart the eating experience of HNC patients. Thus, further investigations on food adjustments for this patient group seem warranted.


Asunto(s)
Neoplasias de Cabeza y Cuello , Humanos , Estudios Transversales , Neoplasias de Cabeza y Cuello/complicaciones , Boca , Saliva , Percepción del Gusto
12.
J Affect Disord ; 341: 185-193, 2023 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-37657618

RESUMEN

Borderline Personality Disorder (BPD) is often characterized by self-injurious behaviors, with one-half to two-third of these patients reporting hypalgesic or analgesic phenomena during self-harming. Research on pain perception in BPD suggested abnormal processing of nociception either within the sensory-discriminative and/or motivational-affective systems of pain. Nevertheless, it is still unclear whether pain insensitivity could be generalized to other somatosensory submodalities. To investigate this question, 30 BPD patients and 30 matched healthy controls were enrolled in the current study and underwent a somatosensory battery composed of well-established psychophysical test assessing all the principal submodalities of somatosensation, namely pain perception (i.e., warm, cold and mechanical), discriminative touch (i.e., tactile acuity and tactile sensitivity) as well as affective touch. Results showed abnormal warm detection threshold, warm pain threshold, mechanical pain perception, and tactile sensitivity in BPD patients, but no differences emerged neither for tactile acuity nor for cold pain thresholds, cold tolerance, or for affective touch perception. Findings point to a deficit in nociception, as well as in tactile sensitivity in BPD individuals, and were discussed in relation to BPD clinical features including self-injurious behaviors.


Asunto(s)
Trastorno de Personalidad Limítrofe , Percepción del Tacto , Humanos , Tacto , Dolor , Umbral del Dolor
13.
J Dent Educ ; 87(3): 374-384, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36326571

RESUMEN

BACKGROUND: Participating in recreational activities from a young age may have the potential enhance psychomotor skills early on, and conversely, low levels of participation in these activities may predict slower development of preclinical hand skills. PURPOSE: This study aims to evaluate the eye-hand coordination benefits of leisure and reflex-based activities to those of typical instructional techniques among dental students. DATA SOURCES: The databases used were PubMed, EBSCOhost, and Scopus. STUDY SELECTION: Ten articles were selected from a total of 1135 articles found across three databases. DATA EXTRACTION: The articles were screened by four investigators through a series of steps in accordance to inclusion and exclusion criteria and rid of any duplicates. DATA SYNTHESIS: The majority of the 10 featured articles were conducted in the United States. All of the research included was cohort observational studies. This systematic review includes a total of 1975 participants from the publications selected for this purpose. RESULTS: Manual dexterity may be taught and improved by practice, and tests designed to measure it should be used primarily to pinpoint which students would benefit most from individualized, close supervision during their education. CONCLUSION: Researchers found that reflex-based activities helped students develop better hand-eye coordination in a classroom setting. However, more precise dental-related tests and questionnaires can always be developed through further study; doing so would yield a wealth of information that would be immensely useful to the dental sector.


Asunto(s)
Educación en Odontología , Evaluación Educacional , Humanos , Educación en Odontología/métodos , Reflejo , Estudiantes , Escolaridad
14.
Sensors (Basel) ; 21(24)2021 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-34960340

RESUMEN

Tactile hallucinations frequently occur after mental illnesses and neurodegenerative diseases like Alzheimer's and Parkinson's disease. Despite their common occurrence, there are several complicating factors that make it difficult to elucidate the tactile hallucinations. The forehead tactile hallucination, evoked by the physical object approaching to the forehead, can be easily and consistently evoked in healthy-bodied subjects, and therefore it would help with investigating the mechanism of tactile hallucinations. In this pilot study, we investigated the principles of the forehead tactile hallucination with eight healthy subjects. We designed the experimental setup to test the effect of sharpness and speed of objects approaching towards the forehead on the forehead tactile hallucination, in both a physical and virtual experimental setting. The forehead tactile hallucination was successfully evoked by virtual object as well as physical object, approaching the forehead. The forehead tactile hallucination was increased by the increase of sharpness and speed of the approaching object. The forehead tactile hallucination also increased the tactile sensitivity on the forehead. The forehead tactile hallucination can be solely evoked by visual feedback and augmented by the increased perceived risk. The forehead tactile hallucination also increases tactile sensitivity. These experimental results may enhance the understanding of the foundational mechanisms of tactile hallucinations.


Asunto(s)
Trastornos Mentales , Enfermedad de Parkinson , Frente , Alucinaciones , Humanos , Proyectos Piloto
15.
Braz J Phys Ther ; 25(6): 846-853, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34535410

RESUMEN

BACKGROUND: Foot deformities are highly prevalent in older adults and negatively impact their mobility and quality of life. However, the association between foot problems and physical function is still unclear. OBJECTIVE: To investigate whether structural foot deformities and plantar tactile sensitivity are associated with lower extremity physical function impairment in community-dwelling older adults. METHODS: We included 200 men and women aged 60 years and older from a community-based program. The foot assessment included toe deformities and calluses inspection and evaluation of plantar tactile sensitivity using monofilaments. The Short Physical Performance Battery (SPPB) was used to assess lower extremity physical function. We conducted a multivariate logistic regression analysis to investigate the association between foot problems and lower extremity physical function. RESULTS: Hallux valgus was the most prevalent deformity among older adults. Those participants with reduced plantar tactile sensitivity (OR= 2.77; 95% CI: 1.38, 5.55) and a hallux valgus (OR= 2.23; 95% CI: 1.10, 4.52) were more likely to present poor lower extremity physical function. CONCLUSION: Hallux valgus and impaired plantar sensitivity were associated with reduced lower extremity physical function in older adults. Further studies are necessary to identify this causality and to what extent management of these foot problems can improve general mobility and quality of life of older adults.


Asunto(s)
Deformidades del Pie , Vida Independiente , Anciano , Femenino , Pie , Humanos , Masculino , Persona de Mediana Edad , Calidad de Vida
16.
Motor Control ; 25(4): 616-630, 2021 Sep 16.
Artículo en Inglés | MEDLINE | ID: mdl-34530402

RESUMEN

The team developed the newly compiled eight methods and five steps of Tai Chi (EMFSTC), which includes introductory routines to Tai Chi characterized by simple structures. This study examined the effectiveness of EMFSTC practice on balance control. A total of 31 participants were randomly assigned to EMFSTC (n = 15, age = 66.4 ± 1.7 years, received 16-week EMFSTC practice) or control (n = 16, age = 66.7 ± 1.8 years, received no practice) groups. Significant group by training interactions were observed. After EMFSTC practice, balance control improved, as indicated by decreased root mean square and mean velocity of center of pressure, proprioception threshold during knee extension, and plantar tactile sensitivity threshold at the arch. EMFSCT can be an effective rehabilitation modality to improve balance control among older adults.


Asunto(s)
Taichi Chuan , Anciano , Pie , Humanos , Persona de Mediana Edad , Equilibrio Postural , Propiocepción
17.
J Contemp Dent Pract ; 22(3): 268-272, 2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-34210927

RESUMEN

AIM: To evaluate the active tactile sensitivity in individuals with complete natural dentition, determining the smallest thickness detected by the participants, and clarifying if there is a difference between the thicknesses analyzed. MATERIALS AND METHODS: Active tactile sensitivity was evaluated in 40 research participants. Inclusion criteria included participants with complete natural dentition, without active or history of periodontal disease, absence of temporomandibular disorders, bruxism, and restorations in the evaluated area. Exclusion criteria included age below 18 years. The active tactile perception threshold was evaluated by using carbon sheets of different thicknesses (0, 12, 24, 40, 80, 100, and 200 µm), which were inserted in the participants' premolars, bilaterally. The carbon sheet was inserted so as not to come into contact with the oral soft tissues. Subsequently, the participant occluded and was asked about the perception of the intraocclusal object 20 times in each occlusal contact. The collected data were tabulated considering the amount of positive and negative responses for each carbon thickness. Values of p < 0.05 were considered significant. RESULTS: The results showed that there was linearity in perception, on both sides, besides, the natural dentition was able to perceive difference in thickness from 12 µm. CONCLUSION: We conclude that the 12 µm thickness is noticeable in occlusion and can be differentiated from other thicknesses in natural dentition and that there is no difference between the tactile sensitivity of the right and left sides. CLINICAL SIGNIFICANCE: A better understanding of active oral tactile sensitivity will contribute to numerous clinical applications in dentistry, including occlusal adjustment in dental rehabilitation, dental implants prosthesis design, and survival of prosthetic rehabilitation.


Asunto(s)
Bruxismo , Boca Edéntula , Adolescente , Oclusión Dental , Dentición , Humanos , Tacto
18.
Appetite ; 161: 105088, 2021 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-33385476

RESUMEN

Over two studies we investigated the effect of various written interventions (passages) on the disgust response towards a food (falafels) which supposedly contained mealworm (insect) flour. Actually, participants (Study 1 N = 80, Study 2 N = 78) were given the same non-mealworm containing food in all conditions. Disgust was measured using: tactile sensitivity, food intake, liking and desire to eat. Results of Study 1 showed that a sustainability passage (sustainability advantages of entomophagy), but not a delicacy passage (oro-sensory qualities of insects), was effective in reducing disgust. In Study 2, contrary to prediction, a passage describing the sustainability and nutritional advantages entomophagy failed to reduce disgust - falafel intake, liking and desire to eat were decreased. However, a passage which described how mealworm flour is produced, did significantly reduce disgust. Taken together, these studies demonstrate that written passages can alter the disgust response, notably resulting in a maintenance of food intake. Interventions that increase the perception of familiarity of a novel food, but not logic-based arguments, may be a key driver of the amelioration of disgust. These results also support the suggestion that altering the ideational component of disgust can result in changes of distaste perception.


Asunto(s)
Asco , Animales , Preferencias Alimentarias , Humanos , Insectos , Reconocimiento en Psicología , Verduras
19.
Front Syst Neurosci ; 15: 802148, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-35126063

RESUMEN

The sense of body ownership, the feeling that one's own body belongs to oneself, is generated from the integration of visual, tactile, and proprioceptive information. However, long-term non-use of parts of the body due to physical dysfunction caused by trauma or illness may disturb multisensory integration, resulting in a decreased sense of body ownership. The rubber hand illusion (RHI) is an experimental method of manipulating the sense of ownership (SoO). In this illusion, subjects feel as if the rubber hand in front of them were their own hand. The RHI elicits the disownership phenomenon; not only does the rubber hand feels like one's own hand, but one's own hand does not feel like one's own hand. The decrease of ownership of one's own body induced by the bodily illusion is accompanied by neurophysiological changes, such as attenuation of somatosensory evoked potential and decreases in skin temperature. If the loss of the SoO is associated with decreased neurophysiological function, the dysfunction of patients complaining of the loss of ownership can be exacerbated; appropriate rehabilitation prescriptions are urgently required. The present study attempted to induce a sense of disownership of subjects' own hands using the RHI and investigated whether the tactile sensitivity threshold was altered by disownership. Via questionnaire, subjects reported a decrease of ownership after the RHI manipulation; at the same time, tactile sensitivity thresholds were shown to increase in tactile evaluation using the Semmes-Weinstein monofilaments test. The tactile detection rate changes before and after the RHI were negatively correlated with the disownership-score changes. These results show that subjects' sense of disownership, that their own hands did not belong to them, led to decreases in tactile sensitivity. The study findings also suggest that manipulating of illusory ownership can be a tool for estimating the degree of exacerbation of sensory impairment in patients. Consideration of new interventions that optimize the sense of body ownership may contribute to new rehabilitation strategies for post-stroke sensory impairment.

20.
Front Bioeng Biotechnol ; 9: 744307, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-35096786

RESUMEN

Understanding the processing of tactile information is crucial for the development of biofeedback interventions that target cutaneous mechanoreceptors. Mechanics of the skin have been shown to influence cutaneous tactile sensitivity. It has been established that foot skin mechanics are altered due to foot posture, but whether these changes affect cutaneous sensitivity are unknown. The purpose of this study was to investigate the potential effect of posture-mediated skin deformation about the ankle joint on perceptual measures of foot skin sensitivity. Participants (N = 20) underwent perceptual skin sensitivity testing on either the foot sole (N = 10) or dorsum (N = 10) with the foot positioned in maximal dorsiflexion/toe extension, maximal plantarflexion/toe flexion, and a neutral foot posture. Perceptual tests included touch sensitivity, stretch sensitivity, and spatial acuity. Regional differences in touch sensitivity were found across the foot sole (p < 0.001) and dorsum (p < 0.001). Touch sensitivity also significantly increased in postures where the skin was compressed (p = 0.001). Regional differences in spatial acuity were found on the foot sole (p = 0.002) but not dorsum (p = 0.666). Spatial acuity was not significantly altered by posture across the foot sole and dorsum, other than an increase in sensitivity at the medial arch in the dorsiflexion posture (p = 0.006). Posture*site interactions were found for stretch sensitivity on the foot sole and dorsum in both the transverse and longitudinal directions (p < 0.005). Stretch sensitivity increased in postures where the skin was pre-stretched on both the foot sole and dorsum. Changes in sensitivity across locations and postures were believed to occur due to concurrent changes in skin mechanics, such as skin hardness and thickness, which follows our previous findings. Future cutaneous biofeedback interventions should be applied with an awareness of these changes in skin sensitivity, to maximize their effectiveness for foot sole and dorsum input.

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