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The human body has dedicated receptors for sensing temperature and touch, but not wetness. How then is wetness perceived? To test if wetness perception arises from the sensory integration of touch and temperature, and to quantify its measurement in humans, we designed a wetness perception monitor (WPM) which enabled variation of temperature at the fingertips of participants while measuring the pressure exerted on a test surface in the controlled environment of a moisture-free chamber. Thirty randomly selected adults (18+ years) were tested for their perception of dampness/wetness using the WPM. Our data suggest that humans perceive dampness and wetness at average temperatures of 22 ± 0.4°C and 18 ± 0.5°C, respectively, and these sensations are extinguished at temperatures below 16 ± 1°C. Measurements were obtained at an average tactile pressure of 1.5 ± 0.3 kPa. Young adults (18–35 years) sensed wetness at significantly higher temperatures than middle-aged adults (36–55 years) or mature adults (56+ years), who sensed wetness at similar temperatures. We found a surprising sex difference in wetness perception, with females sensing wetness at higher temperatures than males. When the data were screened for outliers, we found that participants whose readings were outside normal ranges, self-reported sensory deficits suggesting that wetness perception could potentially be used as a noninvasive biomarker.

Contemporary approaches to pressure injury (PI) risk identification rely on the use of risk assessment tools and visual skin assessment. Objective biophysical measures that assess skin hydration, melanin, erythema and lipids have not been traditionally used in PI risk; however, these may prove useful as a risk assessment tool. The relationship between subjective visual assessments of skin condition, biophysical measures and PI risk warrants investigation. This study used a descriptive correlational design to examine the relationship between measures of skin hydration, colour (melanin and erythema) and lipids at PI-prone areas amongst geriatric persons (n = 38), obtained using biophysical skin measures and visual skin assessment. Twice daily measures of epidermal hydration, colour and lipids were assessed using the SD202 Skin Diagnostic (Courage + Khazaka GmBH, Cologne, Germany) over pressure-prone areas of the body of study participants over seven consecutive days. Concurrent visual assessment of skin hydration and colour was performed. Results obtained using the SD202 Skin Diagnostic were compared with results gathered from visual assessment and examined for their association with participants' PI risk based on scores of the Norton Risk Assessment Scale. While epidermal hydration and skin colour reading scores did not vary significantly over the data collection period, lipid readings could not be registered on any occasion. With the exception of skin dryness, skin parameters via both objective and subjective means had significant, positive correlations. Statistically significant correlations emerged between visual assessment of skin wetness at the sacrum (r = -0·441, P < 0·01) and ischia (r = -0·468, P < 0·01) and Norton Risk Assessment Scale scores. It was found that the objective assessment of epidermal hydration (skin wetness) was also significantly associated with PI risk at the sacrum (r = -0·528, P < 0·01), as well as the right ischia (r = -0·410, P < 0·05) and left ischia (r = -0·407, P < 0·05). Erythema, when assessed objectively, was significantly correlated with PI risk at the sacrum (r = -0·322, P < 0·05). Such findings indicating that the finer measures afforded by the SD202 Skin Diagnostic in the assessment of the subtle red hues displayed in erythematous skin may provide an additional advantage over traditional, clinician assessment.

Cold sensations are suggested as the primary inducer of the perception of skin wetness. However, limited data are available on the effects of skin cooling. Hence, we investigated the role of peripheral cold afferents in the perception of wetness. Six cold-dry stimuli (producing skin cooling rates in a range of 0.02 to 0.41°C/s) were applied on the forearm of 9 female participants. Skin temperature and conductance, thermal and wetness perception were recorded. Five out of 9 participants perceived wetness as a result of cold-dry stimuli with cooling rates in a range of 0.14 to 0.41°C/s, while 4 did not perceive skin wetness at all. Although skin cooling and cold sensations play a role in evoking the perception of wetness, these are not always of a primary importance and other sensory modalities (i.e. touch and vision), as well as the inter-individual variability in thermal sensitivity, might be equally determinant in characterising this perception.

Relevance of local skin wettedness (w (local)) to general thermal comfort while wearing clothing was investigated in eight males. In the experiments, skin wettedness of the whole body (w (body)) was controlled to be around the thermal comfort limit, while w (local) in different target locations of equal area (anterior and dorsal torso, arms, and thighs) was pushed beyond the comfort limit using special test garments. Subjects walked on a treadmill at 4.5 km h(-1) under 22 degrees C 50% RH. Arms and thighs were thermally in discomfort when their w (local) exceeded 0.32. On the other hand, discomfort in the anterior and dorsal torso was initiated when their w (local) arrived at 0.42 and 0.45. That is, the relation of the local comfort limit with w (local) differed depending upon the location. It was observed; however, that general discomfort was not induced when w (body) remained below 0.36 even if w (local) was higher than its local comfort limit.

Little work has been done in the past on how clothing thermal and moisture transport properties affect human comfort sensations during different periods of an exercise. In this work, by correlating the thermal and moisture transport properties of T-shirt fabrics and garments with the comfort sensations during different stages of exercises, we found that thickness, thermal insulation and warm/cool feeling of the T-shirt fabrics are important to warmth sensation, skin wetness sensation and overall comfort throughout the entire period of exercise and immediately after the exercise. Water vapor transmission properties of T-shirt fabrics or garments are not important to comfort sensations at the start of the exercise, but become an important factor to comfort sensations in the middle of the exercise up to the resting period after the running exercise, probably due to the fact that sweating occurs during these periods. Fabric water absorption and air permeability are not significant factors at the start and during the exercise, but are important after exercise, probably because these properties determine how quickly the skin can be dried after sweating.

Background/purpose: Excessive skin hydration from occlusive coverings such as absorbent articles, bandages, etc. has been known to compromise the skin's barrier properties. Damage to the stratum corneum occurs from prolonged exposure to wetness and limited product breathability, which reduces evaporation. Protection from wetness may be imparted by barrier materials, such as lotions and ointments on the skin. Barrier materials are traditionally applied by hand from bulk containers (bottle or tube). In recent years, diapers have been made that contain barrier ointments designed to transfer to the skin during wear. The purpose of this research was to develop a reliable in vivo method for evaluating skin wetness protection when using personal products. Method: The means for evaluating wetness protection in vivo is dye exclusion evaluation on human skin. Dye exclusion involves application of a barrier material, followed by dye application and skin staining evaluation. The dye exclusion method may be conducted on adult forearms with direct application of the barrier material or on infant or adult torsos after wearing a diaper or incontinence product (or other personal products) that contains the barrier material. Dye exclusion on infants used cosmetic dyes (safe for use in the eye area). Results: Dye exclusion demonstrated skin protection on both adult forearms and on infant buttocks. Ointments in diapers protected the skin from the dye when diapers were worn from a few hours to several days (with appropriate changes of product). Conclusion: The dye exclusion method was able to demonstrate the advantage of barrier ointments for wetness protection and also to discriminate between ointment formulations.

Although the ability to sense skin wetness and humidity is critical for behavioural and autonomic adaptations, humans are not provided with specific skin receptors for sensing wetness [1]. We have recently demonstrated that humans perceive the wetness experienced when the skin is in contact with a wet surface through a multisensory integration of thermal and tactile inputs generated by the interaction between skin and moisture [2]. To further the understanding on the neurophysiology of human skin wetness perception, here we tested the hypothesis that the perception of sweat-induced skin wetness can be significantly manipulated, independently from the level of physical skin wetness.

Humans sense the wetness of a wet surface through the somatosensory integration of thermal and tactile inputs generated by the interaction between skin and moisture. However, little is known on how wetness is sensed when moisture is produced via sweating. We tested the hypothesis that, in the absence of skin cooling, intermittent tactile cues, as coded by low-threshold skin mechanoreceptors, modulate the perception of sweat-induced skin wetness, independently of the level of physical wetness. Ten males (22 yr old) performed an incremental exercise protocol during two trials designed to induce the same physical skin wetness but to induce lower (TIGHT-FIT) and higher (LOOSE-FIT) wetness perception. In the TIGHT-FIT, a tight-fitting clothing ensemble limited intermittent skin-sweat-clothing tactile interactions. In the LOOSE-FIT, a loose-fitting ensemble allowed free skin-sweat-clothing interactions. Heart rate, core and skin temperature, galvanic skin conductance (GSC), and physical ( wbody) and perceived skin wetness were recorded. Exercise-induced sweat production and physical wetness increased significantly [GSC: 3.1 μS, SD 0.3 to 18.8 μS, SD 1.3, P < 0.01; wbody: 0.26 no-dimension units (nd), SD 0.02, to 0.92 nd, SD 0.01, P < 0.01], with no differences between TIGHT-FIT and LOOSE-FIT ( P > 0.05). However, the limited intermittent tactile inputs generated by the TIGHT-FIT ensemble reduced significantly whole-body and regional wetness perception ( P < 0.01). This reduction was more pronounced when between 40 and 80% of the body was covered in sweat. We conclude that the central integration of intermittent mechanical interactions between skin, sweat, and clothing, as coded by low-threshold skin mechanoreceptors, significantly contributes to the ability to sense sweat-induced skin wetness.

■ Most infants experience nappy rash between 7 and 9 months ■ Skin wetness, increase in skin pH and the presence of faecal enzymes are the primary factors associated with skin breakdown ■ Nappy rash is preventable ■ Treatment of nappy rash is often based on trial and error ■ Useful preparations include barrier creams, antibacterials, antifungals and steroids depending on the severity and extent of rash

Background/aims: Excessive skin hydration resulting from wet undergarments is a major cause of diaper rash in children and contributes to severe dermatitis in incontinent adults. Advancements in absorbent technology have led to diapers and incontinent garments that not only absorb urine, but also transfer it to different regions, and lock it away from the skin. The purpose of the present study was to develop a reliable method to assess the effectiveness of absorbent articles in mitigating skin hydration. Methods: Disposable diapers with different absorbent structures were wrapped around the forearms of adult volunteers, loaded with urine substitute, and held in place for 1 h. Hydration of the volar region was measured by evaporimetry and compared with that of skin in the diaper region of children who had worn control loaded diapers in the usual way. The amount of fluid retained in various diaper layers and in the superabsorbent polymer core was measured. Conclusions: Evaporative water loss measurement on adult forearms was shown to be a reliable test for comparing the effectiveness of absorbent articles in preventing excessive skin hydration provided that 1) the complete garment was used and 2) fluid was loaded in a manner that simulated normal urination. Skin on adult forearms and skin in the diaper region of children were concordant in their response to wet diapers. Skin wetness was directly related to the amount of liquid retained in absorbent layers close to the skin.

Human skin is innervated with a variety of receptors serving somatosensation and includes the sensory sub-modalities of touch, temperature, pain and itch. The density and type of receptors differ across the body surface, and there are various body-map representations in the brain. The perceptions of skin sensations outside of the specified sub-modalities, e.g. wetness or greasiness, are described as 'touch blends' and are learned. The perception of wetness is generated from the coincident activation of tactile and thermal receptors. The present study aims to quantify threshold levels of wetness perception and find out if this differs across body sites. A rotary tactile stimulator was used to apply a moving, wetted stimulus over selected body sites at a precise force and velocity. Four wetness levels were tested over eight body sites. After each stimulus, the participant rated how wet the stimulus was perceived to be using a visual analogue scale. The results indicated that participants discriminated between levels of wetness as distinct percepts. Significant differences were found between all levels of wetness, apart from the lowest levels of comparison (20 μl and 40 μl). The perception of wetness did not, however, differ significantly across body sites and there were no significant interactions between wetness level and body site. The present study emphasizes the importance of understanding how bottom-up and top-down processes interact to generate complex perceptions.

Skin wetness is proportional to diaper wetness, and with increased skin wetness, the potential for diaper dermatitis is increased. This study evaluated a wide range of infant diaper products. Eighty healthy volunteers wore 2-inch wetted diaper patches on their volar forearm for two hours. An evaporimeter was used to measure excess skin wetness attributed to the patches. The amount of moisture retained in the patch was also calculated. We found that superabsorbent (SA) disposable diapers kept the skin drier and retained more synthetic urine than cloth reusable and conventional disposable brands, and thus have the greatest potential for helping prevent diaper dermatitis. The SA brands evaluated did an equally adequate job in keeping the skin dry and in retaining moisture. Conventional disposable diapers were less able to keep the skin dry than SA diapers and were not superior to cloth products in most instances. Cloth diapers” performance depended on their composition. Those with several layers of the same fabric were less successful in keeping the skin dry than ones that contained middle layers of different nonwoven components.

During the 1990s, emphasis on the health and safety of people who exercise in hot, humid conditions increased and many organizations became aware of the need for protection against heat-related disorders. A practical, pre-cooling strategy applicable to several sporting codes, which is low cost, easy to use, light-weight and which enhances cooling of the human body prior to and following exercise, was developed and tested. Eight males and eight females participated in a maximal oxygen consumption (VO2max) test and four trials: a control (without cooling) and wearing each of three different cooling vests (A, B, C). Vests were worn during the rest, stretch, warm-up (50% VO2max) and recovery stages of the protocol, but not during the 30 min run (70% VO2max). Core and skin temperatures during exercise were reduced (by approximately 0.5 degrees C, rectal; 0.1-1.4 degrees C, abdominal skin temperature) and sweat rates were lower (by approximately 10-23%). Endurance times for running at 95% of VO2max were increased by up to 49 s. Perceptions of the thermal state and skin wetness showed changes to greater levels of satisfaction. Physiological and sensory responses were related to design features of the vests.

The strength of the association between diaper dermatitis and measurements of skin wetness and skin pH was evaluated by statistical analysis of four diaper trials involving 1601 infants. Although the strength of the association between skin wetness and diaper dermatitis was greater than that between skin pH and diaper dermatitis, increases in wetness and pH were both significantly associated with elevated mean grades for diaper dermatitis. The skin environment least likely to be associated with diaper dermatitis is one In which Increases In both skin wetness and skin pH are minimized.

In a skilled nursing facility, 36 patients (chiefly elderly) with persistent urinary incontinence were the subjects of this study. In their management, the usual disposable pads were compared with a new launderable bed sheet (Kylie) which absorbs urine in the second layer while maintaining a dry surface next to the patient's skin. There was a 42 percent reduction in the frequency of bedding changes with the new bed sheets. The patients experienced increased comfort due to decreased skin wetness and decreased creasing of the sheets. The reduced frequency of bed linen changes permitted longer undisturbed periods for the patient. Management costs were reduced by 40 percent with the launderable bed sheets. There were no adverse effects on the condition of the patients or in the quality of care.

Wearing dry and wet cloth and disposable diaper materials has certain effects on the degree of skin wetness. These, in turn, affect the coefficient of skin friction, the skin's susceptibility to abrasion damage, its permeability, and its support of microbial growth. These effects were explored using an adult model wearing forearm patches. The adult model was validated by comparisons of skin wetness and friction values for infants and adults determined under similar conditions. Skin wetness was proportional to diaper wetness. With increased skin wetness, there were increased coefficients of friction and increased abrasion damage, skin permeability, and microbial growth. Cloth diaper material produced wetter skin than did disposable diaper material at equivalent loadings.

Diaper dermatitis results from the action of a number of physical and chemical factors on the skin. While its etiology is complex, there is agreement that prolonged contact between wet diapers and the skin leading to excessive hydration of the stratum corneum and reduced barrier function is a primary factor. Recent research also indicates that pH elevation resulting from ammonia production increases the probability of skin damage due to fecal enzyme activity. New diapers containing absorbent polymers blended with cellulose fluff in the absorbent core have been developed. The absorbent polymer binds fluids and controls pH in the diaper environment. To assess the effectiveness of these diapers, a clinical study was conducted with approximately 150 infants over 15 weeks, using fluff diapers and absorbent polymer diapers. The results clearly showed that the diapers with absorbent polymer provide a better skin environment than those with fluff only with respect to lower skin wetness and pH control (instrumental measurements). In addition, the clinicians' grades indicated a directional reduction in diaper rash severity.

A new, highly absorbent bed sheet (Kylie sheet) was evaluated against cotton drawsheets in the management of incontinence of urine in a crossover study of 19 male and female geriatric patients. When the new Kylie sheets were in use, there was a significant decrease in skin wetness, in disturbance of patients, in nursing workload, and in laundry costs. There were no adverse effects.