Comparison between sensitive and nonsensitive free flaps in reconstruction of the heel and plantar area

In this study, 12 cases of reconstruction of the heel and plantar area since 1982 are reviewed. Six nonsensate muscle free flaps and six sensate fasciocutaneous flaps were used, respectively. Categories assessed were the time interval for return to daily living activities, sensation to light touch, pinprick, Semmes-Weinstein monofilament test of the reconstructed area for sensory evaluation; and results of pedograms (maximal pressure, pressure distribution, and total contact area of the plantar surface). Follow-up periods were between 2 and 14 years, with an average of 6 years. Better sensory results and early return to daily living activities were observed in the sensate flap group, but the defects were smaller in this group. Despite the slightly longer time to return to daily living activities and worse sensory results, long-term follow-up showed that patients with nonsensate flaps had no difficulty in performing living activities if they continued to be careful and to use some kind of protective shoes. The results of the pedogram analyses were similar between the two groups with regard to total contact area of the reconstructed foot in relation to the healthy foot. Pressure values of the reconstructed areas in sensate flaps were found to be close to pressure values in the same weight areas of the normal foot. The differences between pressure values of the sensate and nonsensate flaps were statistically significant (p < 0.001). Therefore, in reconstruction of the weight-bearing surface of the foot, each case should be evaluated individually. The reconstructive method should be chosen according to the location and soft-tissue requirements of the defect.     

Radiofrequency thermocoagulation of Gasserian ganglion and its rootlets for trigeminal neuralgia.

Thirty-nine patients with trigeminal neuralgia, not controlled by medical treatment, were treated by radio-frequency thermocoagulation of the Gasserian ganglion and its posterior rootlets. Thirty-six received satisfactory pain relief. In 30 patients touch sensation in the treated territory was preserved. The corneal reflex was affected in only six patients, two of whom subsequently developed keratitis. There were no other complications apart from a minor unpleasant sensation in eight patients. By selectively destroying pain fibres this technique offers the scope of preserving touch sensation in the treated area. Moreover, the zone of analgesia can be restricted to the affected region by sensory mapping through electrode stimulation before thermocoagulation. Its simplicity, low morbidity, associated short hospital stay, and the increased ability to preserve touch sensation, especially of the cornea, seem to make it preferable to other forms of surgical management for trigeminal neuralgia.     

Generator locations of movement-related potentials with tongue protrusions and vocalizations: subdural recording in human

Movement-related potentials (MRPs) associated with tongue protrusions and vocalizations were recorded from chronically implanted subdural electrodes over the lower perirolandic area in 7 patients being evaluated for epilepsy surgery. In 3 patients, tongue protrusions elicited a clearly defined, well localized slow negative Bereitschaftspotential (BP) at the motor tongue area, and a positive BP at the sensory tongue area. At the motor tongue area the negative BP was followed by a negative slope (NS′) and a motor potential (MP), and at the sensory tongue area the positive BP and a positive reafferent potential (RAP) were seen but no NS′ and MP could be identified. In the other 4 patients, tongue protrusions elicited positive BP, NS′ and MP at the motor and sensory tongue area, and positive RAP at the sensory area. It was concluded that BPs, NS′ and MPs are mainly generated in the motor cortex involving the crown as well as the anterior bank of the central fissure. The sensory cortex (areas 3a and 3b) also participated in the generation of BPs but to a lesser degree. Different degree of involvement of these multiple generators most likely explains the interindividual variability of polarity and distribution of the MRPs. RAPS most likely arise from primary sensory areas 1 and 2. Brain potentials were also recorded at the motor (2 patients) and sensory (2 patients) language areas, but no specific language-related potentials could be identified.Evoked potentials to lip stimulation were investigated in 4 patients. In 3 patients, the responses at the sensory tongue area (P16, N21 and P30) had the same latency but opposite polarity to those at the motor tongue area. In the other patient, the responses (P16, N21 and P30) at the motor and sensory tongue areas were of the same polarity. The MRPs to tongue protrusions in those 4 patients revealed the same polarity relationship between the pre- and postcentral potentials. However, the maximal amplitude of evoked potentials and MRPs was seen at almost the same electrodes, suggesting that the main generators for these MRPs and evoked potentials must be located at contiguous areas in the anterior and posterior bank, respectively, of the central fissure.     

Investigation into the possible cause of subjective decreased sensory perception in the nipple-areola complex of women with macromastia

Patients with macromastia often comment on a lack of sensation in their nipple-areola complex. A study was designed to investigate the cause of this decreased sensation. Two hypotheses were proposed. First, the decreased sensation could result from neuropraxia of the sensory nerve fibers secondary to traction caused by the heavy breast parenchyma. The second hypothesis proposed that tissue expansion of the nipple and areola by the voluminous breast parenchyma caused a decrease in nerve fibers per surface area and hence decreased sensory perception. Sixty-one patients were assessed in the study. All patients underwent surgery in which histological biopsy of either the areola alone (31 reduction mammaplasty patients) or the nipple and areola (30 mastectomy patients) was possible. Before surgery, each nipple-areola complex was tested with Weinstein Enhanced Sensory Test monofilaments as a quantitative test of tactile sensation. Breast cup size, ptosis, and weight of tissue excised were recorded to allow general assessment of the breast size. The nipple and areola biopsy specimens were assessed using immunohistochemistry (S-100 polyclonal antibody, Dako Z311) to measure nerve fiber count per unit area. Statistical analysis was undertaken to find any association among sensitivity, breast cup size, ptosis, weight of tissue resected, and nerve fiber density in the nipple and areola biopsy specimens. Sensitivity at the areola decreased with increasing breast cup size (r = 0.47, p < 0.001) and ptosis (r = 0.42, p = 0.002 for increasing distance between inframammary crease and nipple; r = 0.49, p < 0.001 for increasing manubrium to nipple distance). There was a weak correlation between nerve fiber density at the areola and breast cup size (r = -0.22, p = 0.1). Sensitivity at the nipple was higher than at the areola. Nerve fiber density count at the nipple was higher than at the areola, but there was no statistically significant correlation between nipple sensitivity and breast cup size, ptosis, or weight of tissue resected. The results suggest that the areola and nipple are different in their neuroanatomy. The areola is a thin, pliable structure that is predisposed to stretch as the breast enlarges and therefore experience a decrease in nerve fiber density. The nipple is a compact structure that is less likely to stretch with breast enlargement. In the nipple, neither sensory perception nor nerve fiber density varied with size or breast ptosis. The perceived lack of sensation in the nipple-areola complex is multifactorial. This study shows that neither traction injury to the sensory nerves nor decreased nerve density alone can explain the subjective numbness reported by patients with macromastia. Psychological factors, such as dissatisfaction with body form or interpretation of lack of sensation in the areola as also affecting the nipple, may influence the patient's assessment of the nipple-areola sensitivity.     

Brain morphology in large pelagic fishes: a comparison between sharks and teleosts

A quantitative comparison was made of both relative brain size (encephalization) and the relative development of five brain area of pelagic sharks and teleosts. Two integration areas (the telencephalon and the corpus cerebellum) and three sensory brain areas (the olfactory bulbs, optic tectum and octavolateralis area, which receive primary projections from the olfactory epithelium, eye and octavolateralis senses, respectively), in four species of pelagic shark and six species of pelagic teleost were investigated. The relative proportions of the three sensory brain areas were assessed as a proportion of the total 'sensory brain', while the two integration areas were assessed relative to the sensory brain. The allometric analysis of relative brain size revealed that pelagic sharks had larger brains than pelagic teleosts. The volume of the telencephalon was significantly larger in the sharks, while the corpus cerebellum was also larger and more heavily foliated in these animals. There were also significant differences in the relative development of the sensory brain areas between the two groups, with the sharks having larger olfactory bulbs and octavolateralis areas, whilst the teleosts had larger optic tecta. Cluster analysis performed on the sensory brain areas data confirmed the differences in the composition of the sensory brain in sharks and teleosts and indicated that these two groups of pelagic fishes had evolved different sensory strategies to cope with the demands of life in the open ocean.     

Long term effects of cryosurgery on cutaneous sensation.

In a study of the time course and nature of the sensory loss after cryosurgery the forearms of nine normal subjects were treated with liquid nitrogen using freeze times currently employed in clinical practice in Britain. Ability to appreciate touch, pinprick, and cold in the treated areas was tested at regular intervals and biopsy samples taken to investigate the pathogenesis. Appreciation of all three modalities of sensation was initially reduced in all nine subjects for all freeze times, yet complete recovery occurred in the seven patients completing follow up. This recovery, however, took up to one and a half years for the longest freeze, with even a 10 second freeze taking up to 10 months. Patients may be reassured that sensory loss after cryosurgery for up to two periods of 30 seconds will almost certainly recover, though it may take up to 18 months to do so.     

Functional reconstruction using a depressor anguli oris musculocutaneous flap for large lower lip defects, especially for elderly patients

Described here is a new technique to reconstruct large lower lip defects using one or two musculocutaneous island flaps, which includes an innervated depressor anguli oris muscle and has a facial artery in its pedicle. Vermilion is simultaneously reconstructed using a mucosal transposition flap. Three patients who had a total lower lip defect and five patients who had a defect larger than one-half of the lower lip were treated by our procedure. All the flaps survived completely without any signs of vascular stasis. In six patients, sphincter function and sensation appeared within 3 months after surgery. In one patient who needed a total lower lip reconstruction, the depressor anguli oris muscle was atrophic and the motor nerve could not be found. This patient could not regain motion. One other patient complained of a sialorrhea accompanied by sensory loss; however, his sensation improved within 6 months after surgery. All of the reconstructed lower lips were large enough to enable the patient to wear dentures and were of a cosmetically acceptable appearance 1 year after surgery.     

颅内电极在感觉运动区皮质发育不良癫痫手术中的应用

目的：探讨长程颅内电极监测及电刺激方法,在感觉运动区皮质发育不良的难治性癫痫外科手术评估中的意义。方法：筛选MRI提示的皮质发育不良区域与重要功能区-感觉运动区位置关系密切的11例难治性癫痫患者,且头皮长程视频脑电监测及PET检查也初步提示癫痫发作与皮质发育不良所在脑区有关,在可疑脑区放置颅内电极,然后进行颅内电极长程视频脑电监测及电刺激检测,对癫痫起源位置及功能区定位,明确癫痫发作起源区域与感觉运动功能区的解剖学关系,在定位结果指导下进行切除术。结果：11例中3例位于左侧半球,8例位于右侧半球,11例感觉运动功能区皮质分布均存在不同程度变异,7例癫痫发作起源区域与感觉运动功能区一定范围重叠,其中5例与感觉区重叠,该5例切除了起源区域与发作有关的部分感觉区,2例部分致痫灶与运动区重叠,该2例仅切除了除与发作有关的运动区以外的癫痫起源区域,4例癫痫发作起源区域与感觉运动功能区相对独立,该4例完全切除癫痫发作起源区域;手术后6例患者发作消失,2例患者发作频率减少90%以上,1例癫痫发作控制无效,2例患者发生部分感觉缺失,但对生活无明显影响。结论：在皮质发育不良的癫痫患者中,有较高比例的病人伴有功能区皮层分布的变异,长程颅内电极监测及电刺激能够实现癫痫起源区域及功能区精确定位,明确功能区变异情况,对于指导病灶切除,避免损伤功能区皮质,减少术后并发症具有重要意义。     

颅内电极在感觉运动区皮质发育不良癫痫手术中的应用

目的:探讨长程颅内电极监测及电刺激方法,在感觉运动区皮质发育不良的难治性癫痫外科手术评估中的意义。方法:筛选MRI提示的皮质发育不良区域与重要功能区-感觉运动区位置关系密切的11例难治性癫痫患者,且头皮长程视频脑电监测及PET检查也初步提示癫痫发作与皮质发育不良所在脑区有关,在可疑脑区放置颅内电极,然后进行颅内电极长程视频脑电监测及电刺激检测,对癫痫起源位置及功能区定位,明确癫痫发作起源区域与感觉运动功能区的解剖学关系,在定位结果指导下进行切除术。结果:11例中3例位于左侧半球,8例位于右侧半球,11例感觉运动功能区皮质分布均存在不同程度变异,7例癫痫发作起源区域与感觉运动功能区一定范围重叠,其中5例与感觉区重叠,该5例切除了起源区域与发作有关的部分感觉区,2例部分致痫灶与运动区重叠,该2例仅切除了除与发作有关的运动区以外的癫痫起源区域,4例癫痫发作起源区域与感觉运动功能区相对独立,该4例完全切除癫痫发作起源区域;手术后6例患者发作消失,2例患者发作频率减少90%以上,1例癫痫发作控制无效,2例患者发生部分感觉缺失,但对生活无明显影响。结论:在皮质发育不良的癫痫患者中,有较高比例的病人伴有功能区皮层分布的变异,长程颅内电极监测及电刺激能够实现癫痫起源区域及功能区精确定位,明确功能区变异情况,对于指导病灶切除,避免损伤功能区皮质,减少术后并发症具有重要意义。     

Sensory reinnervation in microsurgical reconstruction of the heel

Six sensory reinnervation techniques were carried out in 10 patients who underwent reconstruction of the weight-bearing surface of the heel by microsurgical free-tissue transfer. The techniques include the use of neurovascular island flaps, neurosensory flaps, sensory nerve grafts to skin flaps, coaptation of the sensory nerve to the motor nerve of the muscle flaps, direct sensory nerve transfer, and sensory nerve graft transfer. In all patients, some sensation developed, characterized by sensation to light touch, to dull objects, to pinprick, to pain, and to tickling. Three patients developed the ability to distinguish sharp from dull objects and the sensation of pain. The remaining seven had the sensation of touch to various mechanical stimuli. In nine patients, the sensation is located in the weight-bearing surface of the reconstructed heel. Five patients bear weight on the reconstructed surface at least 6 hours per day. Three participate actively in sports. Split-thickness skin graft-muscle flaps were more prone to breakdown than skin flaps. Full-thickness skin flaps appear necessary for the production of pain sensation and the more discriminating sensations. Preliminary results suggest a functional benefit after sensory reinnervation.     

Oral chemical irritation: psychophysical properties

Concentration series of four oral chemical irritants derivedfrom spices (capsicum oleoresin, vanillyl nonamide, piperineand ginger oleoresin) were evaluated for perceived intensityand perceived areas of sensation over time. Growth of sensationwith concentration was described by power function relationshipsand decrements in sensation over time were described by exponentialdecay. Peak sensation intensity was correlated with stimulatedsalivary flow rate. The number of oral areas reported as irritatedincreased with concentration and decreased over time. Whilesome differences were observed among compounds in the areasof stimulation, the dorsal tongue surface and tongue edges werehighly responsive to all compounds. A sequential desensitizationwas observed, in which stimuli were perceived as less strongwhen following a stronger irritant than when following a weakerone.     

Sheep: a model for testing spinal and epidural anesthetic agents.

The sheep was utilized as a model to study local anesthetic agents used for subarachnoid and epidural anesthesia in human beings. Employing injection and evaluation technics similar to those used in human anesthesiology, the onset of anesthesia, development of maximum sensory anesthesia, regression of sensory anesthesia, and complete return of sensation and motor function were measured. Subarachnoid injection with 0.25% tetracaine and epidural injection with 0.25% bupivacaine produced regional anesthesia similar to that observed in humans.     

Evaluation of abdominal sensibility after TRAM flap breast reconstruction

One commonly expressed concern regarding transverse rectus abdominis myocutaneous (TRAM) flap breast reconstruction surgery is the return of sensation to the abdomen. Although many studies have focused on abdominal wall muscle incompetence or herniation, there is limited literature discussing postoperative abdominal sensation. The purpose of this study was to assess abdominal sensation a minimum of 1 year after pedicled TRAM flap surgery for breast reconstruction. Twenty-five female patients who underwent TRAM flap breast reconstruction a minimum of 1 year before the study were compared with 10 female volunteer controls. Subject and control abdomens were specifically divided into 12 zones, then assessed for superficial touch, superficial pain, temperature, and vibration using various techniques. Fischer's exact test was used for analysis with the p value set at p = 0.05. The degree to which superficial touch was affected was then tested using Semmes-Weinstein monofilaments. Student's t test was used for analysis with the p value set at p = 0.05. For all four sensory modalities, subjects were found to have decreased sensation in zones 5 and 8, the supraumbilical and infraumbilical regions. This was statistically significant. When assessed with Semmes-Weinstein monofilaments, the sensation of the subjects' abdomens was significantly decreased compared with controls. Significance was found in all zones. This study clearly demonstrates that there is a significant and persistent reduction in abdominal sensibility following TRAM flap surgery. The distribution of the deficits is consistent and involves the midline supraumbilical and infraumbilical regions. The TRAM flap has become the procedure of choice for postmastectomy autogenous breast reconstruction. It provides the plastic surgeon with a relatively safe, reliable, and aesthetically pleasing method of breast reconstruction. Since its inception, the TRAM flap and its abdominal closure have undergone numerous modifications designed to minimize donor-site morbidity and create a natural-looking breast. In addition to creating an aesthetically pleasing breast, the TRAM flap has the potential advantage of postoperative improvement in abdominal contour.     

The Prevalence and Magnitude of Impaired Cutaneous Sensation across the Hand in the Chronic Period Post-Stroke

Sensation is commonly impaired immediately post-stroke but little is known about the long-term changes in cutaneous sensation that have the capacity to adversely impact independence and motor-function. We investigated cutaneous sensory thresholds across the hand in the chronic post-stroke period. Cutaneous sensation was assessed in 42 community-dwelling stroke patients and compared to 36 healthy subjects. Sensation was tested with calibrated monofilaments at 6 sites on the hand that covered the median, ulnar and radial innervation territories and included both glabrous (hairless) and hairy skin. The motor-function of stroke patients was assessed with the Wolf Motor Function Test and the upper-limb motor Fugl-Meyer Assessment. Impaired cutaneous sensation was defined as monofilament thresholds >3 SD above the mean of healthy subjects and good sensation was ≤3 SD. Cutaneous sensation was impaired for 33% of patients and was 40–84% worse on the more-affected side compared to healthy subjects depending on the site (p<0.05). When the stroke patient data were pooled cutaneous sensation fell within the healthy range, although ∼1/3 of patients were classified with impaired sensation. Classification by motor-function revealed low levels of impaired sensation. The magnitude of sensory loss was only apparent when the sensory-function of stroke patients was classified as good or impaired. Sensation was most impaired on the dorsum of the hand where age-related changes in monofilament thresholds are minimal in healthy subjects. Although patients with both high and low motor-function had poor cutaneous sensation, overall patients with low motor-function had poorer cutaneous sensation than those with higher motor-function, and relationships were found between motor impairments and sensation at the fingertip and palm. These results emphasize the importance of identifying the presence and magnitude of cutaneous sensory impairments in the chronic period after stroke.     

Carbon dioxide laser resurfacing and thin skin grafting in the treatment of "stable and recalcitrant" vitiligo

Various surgical methods have been used in the treatment of small stable vitiliginous areas, but there is no established surgical approach for larger vitiligo areas and therapy-resistant anatomic sites, such as the hands. Two years ago, we successfully treated large burn scar depigmentation areas at different anatomic sites using carbon dioxide laser resurfacing and thin (0.2 to 0.3 mm) skin grafting. The purpose of this study was to investigate the effectiveness of our method in treating large, stable, and recalcitrant vitiligo areas. Thirteen anatomic sites of seven male patients, whose ages ranged from 20 to 22 years, were treated. The locations of the treated areas were as follows: seven areas on the dorsum of the hands, two areas on the forearms, two areas in the pretibial region, one area on the lateral thigh, and one area in the presternal region. The surface area of treated vitiligo sites ranged from 0.5 to 6 percent of total body surface area (mean, 2.5 percent). Skin graft take was excellent in all patients except for one. The follow-up period for these patients ranged from 6 to 18 months, with an average follow-up period of 14 months. Early and complete repigmentation was achieved and the color match was good or excellent in all patients. No depigmentation occurred again in the treated areas or graft donor sites. In conclusion, with careful patient selection and delicate surgical technique, our method was effective in treating large areas of vitiligo over the extremities and dorsum of hands, which were refractory to other therapies and could not be hidden.     

Laser-evoked brain potentials in patients with dissociated loss of pain and temperature sensibility

Brief heat stimuli, elicited by a CO₂ laser (10.6 μm wave length), activate the most superficial cutaneous nerve terminals of the thin myelinated Aδ and unmyelinated C fibres which mediate heat and pain sensations. This paper investigates late cerebral potentials (SEPs) in response to laser pulses in comparison with those to conventional electrical stimulation in 18 patients with a dissociated sensory deficit (intact mechanosensibility and disturbed temperature and pain sensation). Patients were stimulated in the most disturbed limb (affected area) and in a corresponding control area.In all 18 patients the SEPs elicited by laser stimuli were able to identify the body site with heaviest disturbances in pain and thermosensibility: the SEPs from the affected area were reduced or delayed, compared to the control area. In contrast, no alterations in SEPs could be observed after conventional electrical nerve stimulation, in agreement with the normal mechanosensibility. However, the degree of SEP modulation in response to cutaneous heat stimuli did not correspond to the severity of the subjectively reported sensory deficit. Highest correlations between sensory deficits and abnormal SEPs were found in all those patients in whom computer tomography or MR imaging documented a localized destructive process in the CNS. All patients with the smallest SEP modulations despite a considerable sensory deficit had an inflammatory aetiology. Preliminary criteria to define a laser-evoked SEP as pathological are discussed.     

Comparing Survival and Movements of Non-Urban and Urban Translocated Mule Deer

In many parts of North America, deer (Odocoileus spp.) have adapted to live in urban areas and are a source of negative human-wildlife interactions. Management strategies such as culling, immunocontraceptives, sterilization, and translocation have been implemented to manage urban deer populations. In the East Kootenay region of southern British Columbia, urban mule deer (Odocoileus hemionus) populations have been increasing, whereas non-urban mule deer populations have decreased. In 2014 a non-urban mule deer research project began in the area and in 2016 an urban deer translocation trial was approved in the same region. We fit 121 non-urban deer with global positioning system (GPS)-collars and translocated 135 urban mule deer to non-urban areas, of which 57 were fit with GPS-collars. We tested if annual survival between urban translocated (i.e., translocated) and non-urban deer differed, and if translocated deer survival increased in subsequent years after translocation. We also determined if age, body condition, release site, capture area and distance between capture and release sites affected translocated deer survival. We evaluated if translocated deer exhibited different movement behaviors than non-urban deer by comparing probability of migration, maximum net displacement, home range size, and probability of crossing a paved road. Finally, during our study we observed some translocated deer return to a municipal area after translocation and assessed if any covariates such as age, release site, or capture city could help predict this behavior. Annual survival of translocated deer was 0.48 and was significantly lower than survival of non-urban deer, which was 0.77. We observed 20 of 57 collared translocated deer return to a town after translocation. Translocated deer had larger net displacements and larger seasonal home range sizes than non-urban deer. Non-urban deer were more likely to migrate than translocated deer and crossed fewer paved roads than translocated deer. The management effectiveness of translocation to reduce urban deer densities is mixed because annual survival of translocated deer may be lower than may be acceptable to some stakeholders. Additionally, some translocated deer returned to an urban area, and the large distances traveled by deer after translocation may unintentionally spread disease. © 2020 The Wildlife Society.     

See me, hear me, touch me: multisensory integration in lateral occipital-temporal cortex

Our understanding of multisensory integration has advanced because of recent functional neuroimaging studies of three areas in human lateral occipito-temporal cortex: superior temporal sulcus, area LO and area MT (V5). Superior temporal sulcus is activated strongly in response to meaningful auditory and visual stimuli, but responses to tactile stimuli have not been well studied. Area LO shows strong activation in response to both visual and tactile shape information, but not to auditory representations of objects. Area MT, an important region for processing visual motion, also shows weak activation in response to tactile motion, and a signal that drops below resting baseline in response to auditory motion. Within superior temporal sulcus, a patchy organization of regions is activated in response to auditory, visual and multisensory stimuli. This organization appears similar to that observed in polysensory areas in macaque superior temporal sulcus, suggesting that it is an anatomical substrate for multisensory integration. A patchy organization might also be a neural mechanism for integrating disparate representations within individual sensory modalities, such as representations of visual form and visual motion.     

Mach band type lateral inhibition in different sense organs

Experiments were done on the skin with shearing forces, vibrations, and heat stimuli and on the tongue with taste stimuli to show that the well known Mach bands are not exclusively a visual phenomenon. On the contrary, it is not difficult to produce areas of a decreased sensation magnitude corresponding to the dark Mach bands in vision. It is shown on a geometrical model of nervous interaction that the appearance of Mach bands for certain patterns of stimulus distribution is correlated with nervous inhibition surrounding the area of sensation. This corroborates the earlier finding that surrounding every area transmitting sensation there is an area simultaneously transmitting inhibition.     

Comparing sensibility for touch,cold, and warmth in different skin areas

The primary objective of this pilot study was to assess if the magnitude estimation of suprathreshold brushing, warmth (40?°C), and cold (25?°C) stimuli of the skin over the dorsum of the hand and the dorsum of the foot are comparable to the perceived intensity for the same stimuli applied to the skin over any of the following areas: forehead, m. trapezius, m. deltoideus, thoracic back, and lumbar back, respectively. Thirty-two subjects aged 18–64 years were included. Participants were examined by two physicians on two different occasions, 1–58 days apart. Participants rated the magnitude of the perceived sensation of each stimulus on an 11-point numerical rating scale (NRS) 0–10, where 0 was anchored to “no sensation at all for touch/cold/warmth” and 10 anchored to “the most intense imaginable non-painful sensation of touch/cold/warmth”. The criterion for sensory equivalence for one modality was arbitrarily considered satisfactory if two regions had the same numerical rating ±1 point in at least 85% of the individuals. Based on the pre-study criteria for sensory equivalence applied in this study only one area was found to be equivalent to the foot skin for the percept of brushing, that is, the skin over the deltoid muscle and one area for the hand, that is, the skin over the forehead. We failed to find any area with equivalent sensitivity to the hand or the foot for the cold or warm stimuli.