Tactile Thresholds Research Articles

Self-reported Sensory Hypersensitivity Moderates Association Between Tactile Psychophysical Performance and Autism-Related Traits in Neurotypical Adults.

Atypical responses to tactile stimulation have been linked to core domains of dysfunction in individuals with autism spectrum disorder (ASD) and phenotypic traits associated with ASD in neurotypical individuals. We investigated (a) the extent to which two psychophysically derived measures of tactile sensitivity-detection threshold and dynamic range-relate to traits associated with ASD and (b) whether those relations vary according to the presence of self-reported sensory hypersensitivities in neurotypical individuals. A narrow dynamic range was associated with increased autism-related traits in individuals who reported greater sensory hypersensitivity. In contrast, in individuals less prone to sensory hypersensitivity, a narrow dynamic range was associated with reduced autism-related traits. Findings highlight the potential importance of considering dynamic psychophysical metrics in future studies.

Upper extremity disability is associated with pain intensity and grip strength in women with bilateral idiopathic carpal tunnel syndrome.

The upper extremity disability in patients with carpal tunnel syndrome (CTS) is related to dysfunction due to the median nerve damage. However, there is no report on which dysfunctions affect the upper extremity disability. This study aimed to investigate which clinical factors influence upper extremity disability in women with CTS. We analyzed 60 hands of women with bilateral idiopathic CTS. Upper extremity disability was assessed using Hand10, a validated and self-administered tool. Pain intensity was measured using the Japanese version of the Short-Form McGill Pain Questionnaire (SF-MPQ-J). We performed nerve conduction studies, assessed physical and psychological parameters, and collected demographic data. Physical parameters comprised grip strength, pinch strength, tactile threshold, static 2-point discrimination sensation, and severity of numbness. Psychological parameters include depression, pain anxiety, and distress. The bivariate analysis revealed that Hand10 was significantly correlated with age, symptom duration, SF-MPQ-J, grip strength, pain anxiety, and distress. Multiple regression analysis demonstrated that SF-MPQ-J and grip strength were related to Hand10 score. Pain intensity and grip strength were dysfunctions affecting the upper extremity disability in women with bilateral idiopathic CTS. Rehabilitation approaches for CTS should be considered based on the adaptive activities of the neural networks.

Effect of modulating braille dot height on reading regressions.

It is well known that people who read print or braille sometimes make eye or finger movements against the reading direction. The way these regressions are elicited has been studied in detail by manipulating linguistic aspects of the reading material. Actually, it has been shown that reducing the physical intensity or clarity of the visual input signal can also lead to increased regressions during reading. We asked whether the same might be true in the haptic realm while reading braille. We set the height of braille dots at three different levels (high, medium, and low) and asked adult blind, practiced braille readers to read standardized texts without any repetition of content. The results show that setting the braille dot height near the tactile threshold significantly increased the frequency of regressive finger movements. Additionally, at the lowest braille dot height, braille reading speed significantly diminished. These effects did not occur at braille dot heights that were closer to the height of standard braille (medium and high). We tentatively conclude that this effect may be due to a heightened sense of uncertainty elicited by perception near the threshold that seems to be common to the reading process, independent of the sensory input modality. Furthermore, the described effect may be a feature of a brain area that contributes to the reading process mediated by vision as well as touch.

Preliminary exploration for evaluating acuity of oral texture perception.

Despite the important role of oral texture perception in feeding and nutritional homeostasis, its impairment has not been of particular clinical interest, and no clinical protocol is available to evaluate its acuity. This preliminary study aimed to establish a method to evaluate the acuity of oral texture perception. Because texture perception is regarded as reflecting integrity of the sensorimotor system of the jaw and mouth, we hypothesized that the ability to perceive various aspects of food texture would correlate with each other, and tested our hypothesis in 11 healthy adults. First, we prepared three types of test foods with different dominant textures, each of which comprised a series of stimuli with different ingredient concentrations; we used these test foods in discrimination tests involving pairwise comparison. Tests performed using the up-down staircase method revealed significant correlation among the discrimination thresholds for three test foods, suggesting that acuities of texture perception correlated with each other across different textural attributes. Second, we examined the associations between the acuity of texture perception and some aspects of mechanical sensation of the tongue: tactile and two-point discrimination thresholds, as well as the graininess recognition threshold. The acuity of texture perception of the subjects whose sensitivity was low for at least one of these aspects of mechanical sensation (n = 5) was significantly lower than that exhibited by the other subjects (Wilcoxon rank-sum test, p = 0.0417). We concluded that oral texture perception ability can be evaluated by discrimination tests for specific aspects of texture, using appropriate test foods.

Abstract P1-11-15: Chemotherapy-induced peripheral neuropathy in breast cancer survivors: Comparison of objective and subjective measures

Abstract Background: Chemotherapy-induced peripheral neuropathy (CIPN) is a common, potentially debilitating, and dose-limiting side effect experienced by breast cancer survivors. CIPN encompasses symptoms such as pain, numbness, and tingling, which can be measured subjectively by patient-reported outcomes (PRO), or objectively by quantitative sensory testing (QST); however, little is known how QST correlates with symptom profiles measured by PRO. Methods: We conducted a cross-sectional analysis using baseline data of two ongoing clinical trials of breast cancer survivors who experienced moderate to severe CIPN defined by pain, numbness, or tingling ratings of four or greater on a numeric rating scale (NRS) after chemotherapy completion for at least three months. PRO measures of CIPN symptoms included Neuropathic Pain Scale (NPS) and Functional Assessment of Cancer Therapy-Gynecologic Oncology Group/Neurotoxicity subscale (FACT/GOG-Ntx). QST included tactile threshold (TT) measured by Von Frey's filaments, and vibration threshold (VT) measured by biothesiometer. We ran a Spearman correlation to assess the relationship between the subjective measures (NPS and FACT/GOG-Ntx) and objective measures (TT and VT QST). Results: We included 52 sets of baseline data on 50 unique patients; two patients were enrolled in both trials at different times. Mean age was 61 years (SD 10) and 66% were white. The mean NRS pain score was 3.9 (SD 2.8), numbness 5.7 (SD 2.2), and tingling 4.3 (SD 2.8) on a 0-10 scale. The mean NPS total score was 39.2 (SD 23.1) on a 0-100 scale, and FACT/GOG-Ntx was 26.2 (SD 6.8) on a 0-44 scale. High scores on NRS and NPS and low scores on FACT/GOG-Ntx signify more severe CIPN symptoms. See Table 1 for a summary of the correlation between two questions on FACT/GOG-Ntx on tingling/numbness in hands and feet, and NPS total score with QST. A moderate correlation was observed between FACT/GOG-Ntx and QST results, suggesting patient-reported hand and foot numbness or tingling is associated with decreased hand and foot tactile and vibration perception. NPS was positively correlated with tactile perception for the hand and foot, but not with vibration perception. Table 1.Correlation between objective and subjective measures of CIPN Tactile QSTVibration QST HandFeetHandFeetFACT/GOG-Ntx-0.33 (P=0.018)-0.28 (P=0.045)-0.37 (P=0.008)-0.40 (P=0.0034)NPS0.34 (P=0.015)0.32 (P=0.022)0.22 (P=0.12)0.03 (P=0.81) Conclusions: A mild to moderate correlation was observed between subjective and objective measurements of CIPN. As CIPN presents a diverse range of symptoms, better quantifying the subjective and objective measures of CIPN can help incorporate these tools in observational and intervention trials. Understanding the correlation between PRO and QST can help establish QST as a reliable objective measurement of CIPN symptoms, and enable targeted interventions to alleviate CIPN symptoms. Citation Format: Bao T, Kwon A, Piulson L, Chen P, Li Q, Patil S, Seidman A, Blinder V, Vahdat L, Zhi WI, Mao JJ. Chemotherapy-induced peripheral neuropathy in breast cancer survivors: Comparison of objective and subjective measures [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-11-15.

Mechanical sensory threshold in Cavalier King Charles spaniels with syringomyelia-associated scratching and control dogs

It is assumed that Cavalier King Charles spaniels with Chiari-like malformation and syringomyelia experience central neuropathic pain. An association between spinal cord parenchymal lesions and specific clinical signs (e.g. spontaneous and evoked scratching, withdrawal, and paroxysmal pain manifestations with vocalisation) has been suggested. This led to the hypothesis that mechanical sensory threshold is altered in clinical cases. The aim of this study was to quantify the cervical mechanical sensory threshold using Semmes-Weinstein monofilaments in nine Cavalier King Charles spaniels with Chiari-like malformation and assumed syringomyelia-associated central neuropathic pain compared to eight control dogs. Clinical and neurological examination including magnetic resonance imaging was undertaken.Mean mechanical sensory threshold was not significantly different between case and control dogs (t-test on log10 transformed data; P=0.25). Substantial variation within and between dogs was seen, with individual thresholds ranging from 0.04 to 26g in case dogs and from 0.02 to 10g in control dogs. Based on these results, it is unlikely that Cavalier King Charles spaniels with Chiari-like malformation and syringomyelia have increased mechanical sensation characterised by lower mechanical sensory threshold when quantified with Semmes-Weinstein monofilaments. Whether clinical cases experience central neuropathic pain remains unknown. The assessment of sensory function in dogs with assumed central neuropathic pain should be multimodal and include not only mechanical but also tactile and thermal threshold quantification. The use of threshold quantification in a clinical setting is challenging due to an insufficient signal relative to the biological background noise within and between dogs.

Polyester Nanoparticle Encapsulation Mitigates Paclitaxel-Induced Peripheral Neuropathy.

Chemotherapy utilizing cytotoxic drugs, such as paclitaxel (PTX), is still a commonly used therapeutic approach to treat both localized and metastasized cancers. Unlike traditional regimens in which PTX is administered at the maximum tolerated dose, alternative regimens like metronomic dosing are beneficial by administering PTX more frequently and in much lower doses exploiting antiangiogenic and immunomodulatory effects. However, PTX-induced peripheral neuropathy and lack of patient compliant dosage forms of PTX are major roadblocks for the successful implementation of metronomic regimens. Because of the success of polyester nanoparticle drug delivery, we explored the potential of nanoparticle-encapsulated paclitaxel (nPTX) in alleviating peripheral neuropathy using a rat model. Rats were injected intraperitoneally with 2 mg/kg body weight of PTX or nPTX on four alternate days, and neuropathic pain and neuronal damage were characterized using behavioral assessments, histology, and immunohistochemistry. The reduction in tactile and nociceptive pressure thresholds was significantly less in nPTX-treated rats than in PTX-treated rats over a 16-day study period. Histological analysis showed that the degree of dorsal root ganglion (DRG) degeneration and reduction in motor neurons in the spinal cord was significantly lower in the nPTX group than the PTX group. Further, immunofluorescence data reveals that nPTX-treated rats had an increased density of a neuronal marker, β-tubulin-III, reduced TUNEL positive cells, and increased high molecular weight neurofilament in the spinal cord, DRG, and sciatic nerves compared with PTX-treated rats. Therefore, this work has important implications in improving risk-benefit profile of PTX, paving the way for metronomic regimens.

Efficacy of a dissolvable strip with calcium sodium phosphosilicate (NovaMin®) in providing rapid dentine hypersensitivity relief

ObjectiveTo evaluate the efficacy of a dissolvable strip containing 15% w/w calcium sodium phosphosilicate (CSPS) (Novamin®) in providing rapid relief from dentine hypersensitivity (DH). MethodsIn this examiner-blind, proof-of-principle study, 120 healthy adults with DH were randomized 1:1 to the Test strip, professionally applied to facial surfaces of two selected teeth, or to No treatment. Sensitivity was assessed at baseline and 10min, 2h and 4h post-application in response to evaporative (air) and tactile stimuli (measured by Schiff sensitivity scale/a numeric rating scale and tactile threshold, respectively). Change from baseline was analyzed by ANCOVA. ResultsAt 10min post-application, mean Schiff score change from baseline (primary endpoint) was statistically significant with the Test strip (−0.46; 95% confidence intervals [CI]: −0.563, −0.356; p<0.0001) but not with No treatment (−0.02; 95% CI: −0.119, 0.088; p=0.7664). The between-treatment group difference favored the Test strip (difference: −0.44; 95% CI: −0.591, −0.297; p<0.0001). Similar improvements with the Test strip were reported for all other evaporative (air) and tactile sensitivity endpoints (p<0.0001 vs no-treatment) at all timepoints (10min, 2h, 4h). Test strips were considered by most staff and participants slightly/moderately easy to apply (98%). Many participants rated the overall usage experience as “like moderately” (40%) or “like extremely” (20%). There were no treatment-related adverse events. ConclusionThis new CSPS-based technology may provide a novel treatment option for rapid relief from DH (Clinicaltrials.gov NCT02937623). Clinical significanceA dissolvable strip containing 15% w/w calcium sodium phosphosilicate (CSPS) demonstrated significantly greater dentine hypersensitivity reductions following a single application compared with no treatment. Strips were well-liked by participants and generally well tolerated. A strip containing CSPS, which dissolves within 10min, may provide rapid relief from dentine hypersensitivity.

Effects of attachment type and palatal coverage on oral perception and patient satisfaction in maxillary implant-supported complete denture patients.

The effect of oral rehabilitation on the oral perception of implant-supported overdenture patients is a concern. This study evaluated the effects of the attachment type and palatal coverage on oral perception and patient satisfaction in maxillary implant-supported complete denture patients. The correlation between oral perceptual ability (OPA) and patient satisfaction in three groups was investigated. Group I consisted of dentate individuals (n = 40), Group II consisted of maxillary implant-supported complete denture patients with bar attachments and palatal coverage (n = 12), and Group III of maxillary implant-supported complete denture patients with magnetic attachments and palatal coverage (n = 14). In addition, implant-supported maxillary overdentures with bar attachments, with (Group II; n = 12) and without (Group IV; n = 18) palatal coverage, were examined in terms of patient satisfaction and OPA. The relationship between OPA and patient satisfaction was assessed with the Turkish version of the Oral Health Impact Profile-14 (OHIP-TR-14) satisfaction survey. To compare oral sensory function among the groups, tactile awareness and pressure awareness were assessed. There was no significant difference in OHIP-TR-14 scores between Groups II and III. In addition, there was no correlation between oral tactile function and patient satisfaction in Groups II and III. For patients with maxillary bar-retained implant-supported overdentures, palatal coverage did not affect the correlation between OPA and patient satisfaction, lateral pressure threshold, or tactile thickness threshold. According to the results of the study, whether maxillary implant-supported overdentures were made with a bar- or magnetic-type retainer, and whether bar-retained implant-supported overdentures had an open or closed palate did not affect the correlation between patient satisfaction and oral perception.

A method development randomised clinical study investigating efficacy of an experimental oral rinse in providing long-term relief from dentinal hypersensitivity

ObjectivesTo evaluate and compare clinical efficacy of a 1.5% dipotassium oxalate monohydrate (KOX)-containing oral rinse (‘Test’) for the relief of dentinal hypersensitivity (DH) against Negative Control and Placebo oral rinses, adjunctive to twice-daily brushing with a standard fluoride dentifrice, after 8 weeks. MethodsThis was a randomised, examiner blind, parallel-group, method development study in participants with DH, assessed at baseline and after 4 and 8 weeks by response to an evaporative (air) stimulus (evaluated by Schiff sensitivity score and a 10-point visual rating scale [VRS]) and a tactile stimulus (Yeaple probe). To boost compliance, study features included recruiting only regular oral rinse users, use of an oral rinse during acclimatisation, weekly supervised rinsing and twice-daily text reminders. ResultsAfter 8 weeks, adjusted mean change from baseline in Schiff sensitivity score was significantly lower in the Test rinse group (n=43) versus the Negative Control group (n=23) (difference: −1.22; 95% CI −1.657, −0.782); tactile threshold score was significantly higher in the Test rinse group compared to the Negative Control rinse (difference: 37.46g; 95% CI: 22.916, 51.995). Similar significant differences in Schiff/tactile scores were also demonstrated after 4 weeks use, after 4 and 8 weeks use as assessed by VRS and as compared to the Placebo rinse (n=23) in all instances. Study products were generally well tolerated. ConclusionsThe Test rinse showed statistically significant improvements in DH compared to the Negative Control and Placebo rinses after 8 weeks twice daily use. Compliance with the rinsing regimen and study visits was excellent. Clinical significanceAdditional compliance features incorporated into this dentinal hypersensitivity study – recruitment of regular oral rinse users only, acclimatisation rinse, weekly supervised rinsing at the study site, twice-daily text reminders – appear to have been of benefit to the overall study design as compliance was high, and primary and secondary objectives were met.

Effects of intranasal oxytocin on tactile perception

In addition to its role in childbirth labor and lactation, oxytocin is a well-known neurohormone, having several prosocial effects. Moreover, oxytocin seems to play a significant modulatory role in painful experiences, due to its participation in central and peripheral processing of nociceptive somatosensory information. Despite studies on oxytocin in pain modulation, there is a scarce literature investigating the role of oxytocin in tactile perception. Here we investigate the effects of 24 and 40 IU intranasal administration of oxytocin in the non-harmful mechanical tactile detection threshold in men. The data showed a significant increase in tactile perception in an experimental 40 IU oxytocin group. We suggest that this effect could be the basis for the oxytocin-bonding effect via touch.

Therapeutic Effect of the Substrate-Selective COX-2 Inhibitor IMMA in the Animal Model of Chronic Constriction Injury.

Enhancement of endocannabinoid signaling has emerged as an attractive strategy for the treatment of pain. In addition to the well-characterized hydrolytic pathways, cyclooxygenase-2 (COX-2) mediated oxygenation is thought to be an alternative route for endocannabinoid metabolism and therefore provides a new avenue for drug intervention. In this study, we examined the therapeutic effect of indomethacin morpholinamide (IMMA), a novel substrate-selective COX-2 inhibitor, in the chronic constriction injury (CCI) mouse model. Treatment with IMMA significantly alleviated hyperalgesia and mechanical allodynia demonstrated by increased thermal withdrawal latency in Hargreaves test and tactile thresholds in Von Frey test. Accumulation of astrocytes and microglia in spinal cord dorsal horn and infiltration of macrophages into the dorsal root ganglion and sciatic nerve were reduced by drug treatment. Co-administration of the CB2 receptor antagonist, but not the CB1 receptor antagonist partially reversed the inhibitory effect of IMMA on pain sensitivity and inflammatory infiltrates. IMMA downregulated the mRNA expression of TNF-α and IL-1β and the production of IL-6 and MCP-1 proteins in the ipsilateral sciatic nerve. The enhanced NF-κB DNA binding activity in the CCI mouse dorsal spinal cord was also significantly reduced, suggesting that inactivation of NF-κB contributes to the anti-inflammatory property of IMMA. However, different from the previous reports showing that IMMA can increase endocannabinoids without interfering with arachidonic acid metabolism, treatment with IMMA failed to elevate the endogenous levels of AEA and 2-AG, but significantly reduced the production of prostaglandin E2 (PGE2). Furthermore, the mRNA expression of enzymes involved in PGE2 production, COX-2 and prostaglandin E synthase 2 in the ipsilateral sciatic nerve was also suppressed by IMMA treatment. Taken together, these results suggested that IMMA might exert anti-nociceptive effects through multiple mechanisms which include, but are not limited to, CB2 receptor activation and reduced PGE2 production.

Effect of sleep restriction on somatosensory sensitivity including occlusal sensation in the orofacial area

PurposeTo investigate the effect of sleep restriction on somatosensory sensitivity related to occlusion. MethodsTwelve healthy participants participated in an experimental voluntary total sleep restriction (SR) study. In a study design, they were invited to sleep as usual, normal sleep (NS) or to restrict their sleep for four nights. Following the SR night, participants were followed for 3 consecutive days including the 2 sleep nights. In NS experiment, all participants were instructed to maintain NS both nights. During all nights, actigraphy data were collected and total sleep time was estimated. On days before and after sleep conditions, all participants underwent measurements of tactile detection threshold (TDT), interocclusal detection threshold (IDT), perception of unpleasantness (POU), and the Epworth sleepiness scale (ESS). ResultsAs expected, total sleep time on the first night in SR experiment was significantly shorter than on the second night in SR experiment and on the first night in NS experiment (P<0.05). ESS values on Day-2 following SR experiment were significantly higher than on Day-1 and Day-3 in SR experiment and Day-2 in NS experiment (P<0.05). There were no significant differences in TDT and IDT between each day at each measurement point in both experiments. POU was significantly lower on Day-2 in SR experiment than on Day-1 and Day-3 in SR experiment and on Day-2 in NS experiment (P<0.05). ConclusionsThe present results suggest that SR affects to occlusal sensation related to POU.

Modulation of tactile perception by Virtual Reality distraction: The role of individual and VR-related factors.

BackgroundVirtual reality (VR) has shown to be an effective distraction method in health care. However, questions remain regarding individual and VR-related factors that may modulate the effect of VR.PurposeTo explore the effect of VR distraction on tactile perception thresholds in healthy volunteers, in relation to personal characteristics and interactivity of VR applications.MethodsA randomized three way cross-over study was conducted to investigate the effects of active and passive VR applications in 50 healthy participants. Main outcome measures were monofilament detection thresholds (MDT) and electrical detection thresholds (EDT). Personal characteristics (e.g. age, gender, susceptibility for immersion) and immersion in the VR conditions were analyzed for their effect on VR induced threshold differences.ResultsThe use of VR caused a significant increase in both MDT and EDT compared to the control condition (MDT: F (2, 76) = 20.174, p < 0.001; EDT F (2, 76) = 6.907, p = 0.002). Furthermore, a significant difference in favour of active VR compared to passive VR was found in MDT (p = 0.012), but not in EDT. No significant gender effect was found. There was a significant positive correlation between age and active VR distraction (r = 0.333, p = 0.018). Immersion in the VR world was positively correlated with the effect of VR, whereas visualization and daydreaming were negatively correlated with VR effects.ConclusionVR increased tactile perception thresholds, with active VR having the largest effect. Results indicate that the efficacy of VR may increase with increasing age. Gender did not affect VR susceptibility.

Sensory function in cluster headache: an observational study comparing the symptomatic and asymptomatic sides.

BackgroundBased on inconsistent sensory alterations demonstrated in cluster headache (CH), the aim of this study was to determine whether patients with CH develop sensory changes in the symptomatic side compared to the asymptomatic side.MethodsQuantitative sensory testing (QST), including pressure pain threshold (PPT), tactile detection threshold (TDT), prick detection threshold (PDT), and two-point detection threshold (2PDT), was evaluated in 16 patients (seven women; age 41.9±6.8 years) with CH. Test sites included the first, second, and third divisions of the trigeminal nerve, cervical spine, and thenar eminence in the symptomatic and asymptomatic sides.ResultsThe symptomatic side, compared to the asymptomatic side, presented significantly decreased PPT in the first (P=0.011; 423.81±174.05 kPa vs 480.13±214.99 kPa) and second (P=0.023; 288.88±140.80 kPa vs 326.38±137.33 kPa) divisions of the trigeminal nerve, significantly increased TDT in the first (P=0.002; 2.44±0.40 vs 1.74±0.24) and second (P=0.016; 1.92±0.34 vs 1.67±0.09) divisions, and increased 2PDT in the first division (P=0.004; 18.13±4.70 mm vs 15.0±4.92 mm) and neck (P=0.007; 45.31±20.65 mm vs 38.44±16.10 mm).ConclusionThese results support the prior evidence suggesting a specific pattern of alteration of sensory function with alterations in the symptomatic side compared to the asymptomatic side.

Sensibilité de l’hémipulpe radiale de l’index — étude des tests de Semmes-Weinstein versus Cochet-Bonnet chez 25 sujets sains

In the presence of a wound to the palm, several methods of evaluation of the cutaneous sensitivity were proposed to search for sensory deficits. Some authors have shown that the sensitivity and specificity of any other test do not reach 100%. Most authors consider that any hand wound in the vicinity of a nerve path must be surgically explored. The purpose of this work was to verify whether the Cochet-Bonnet corneal sensitivity test had a lower cutaneous pulp sensitivity threshold than the Semmes-Weinstein monofilament test. The series included 25 healthy adult subjects. The average age was 30 years old. All were right-handed except one left-handed. None had a history of a medical or surgical pathology of upper limbs. The protocol consisted of evaluating the tactile cutaneous sensitivity threshold of the radial collateral hemi-pulp of the index finger by an independent observer using two tests, the Semmes-Weinstein esthesiometer and the Cochet-Bonnet. The Semmes-Weinstein test consisted of determining the finest monofilament perceived from a kit of 20 calibrated monofilaments from 0.0045 to 447.0 g. The monofilaments were applied one after the other perpendicularly to the hemi-pulp so that the wire bends slightly for 1.5 seconds. The Cochet-Bonnet test consisted of determining the longest perceived monofilament from a 12-length calibrated pen from 0.006 to 0.618 g. The monofilament was applied perpendicularly to the hemi-pulp so that the thread bent slightly for 1.5 seconds. The sensitivity threshold of the radial hemi-pulp of the index was lower with the CB test than with the SW test. The average cutaneous sensitivity threshold of the hemi-pulps of our series was 0.0388 g, which corresponds to the threshold of 0.035 g before 35 years found in the literature. Our results show that in healthy subjects, the threshold of sensitivity of the radial hemi-pulp of the index is lower with the Cochet-Bonnet monofilament test than with the Semmes-Weinstein monofilament test. The material needed to carry out the Cochet-Bonnet monofilament test is cheaper (424 €) and less cumbersome (1 monofilament) than that required for the Semmes-Weinstein monofilament test, which costs more (901 €) and is bulkier (20 monofilaments). It remains to test the sensitivity and specificity of the CB test on wounds of the palm to check the absence of nerve damage.

Pain assessment in hospitalized spinal cord injured patients - a controlled cross-sectional study.

Background and aims Following spinal cord injury (SCI), a majority of individuals may develop neuropathic pain, which further reduces quality of life. Pain is difficult to treat by medication; in fact, medication overuse may aggravate neuropathic pain in SCI by causing central sensitization (CS): a mechanism of hyper-reactivity of the dorsal horn neurons in the spinal cord with amplified cerebral pain response. The purpose of this study was to examine the presence of neuropathic pain and CS above the spinal lesion in SCI, and to investigate whether injury characteristics or medication influenced pain response. Methods Twenty-four SCI patients with various injury characteristics (eight subacute, traumatic injuries, eight chronic, traumatic injuries, eight non-traumatic injuries) and 12 able-bodied controls underwent sensory testing:pressure algometry, Von Frey filaments (sensitivity), and repetitive pinprick stimulation (pain windup). SCI participants also fulfilled a modified version of the McGill Pain Questionnaire. Data were analyzed regarding (i) SCI patients compared with controlgroup and (ii) SCI subgroup comparison (grouped by a) injury characteristics and (b) intake of analgesics, where low-medicated subgroup were prescribed only non-opioids and high-medicated potent opioids). Results Neuropathic pain was present in 21 of 24 SCI patients. Chronic and non-traumatic SCI patients reported considerably higher present pain intensity than sub-acute traumatic SCI patients on a five-point scale (3.13±0.99, 1.75±1.75 and 0.13±0.35, respectively, p<0.005). Reduced pressure pain detection thresholds (PPDT) were found in SCI patients at several supra-lesional anatomical points compared to controls. Contrarily, tactile detection thresholds were higher in SCI. SCI subgroup analyses showed that i) the low-medicated SCI subgroup displayed significantly lower PPDT compared to the high-medicated subgroup, ii) pain-windup was present in all subgroups although the sub-acute and non-traumatic subgroups displayed lesser pain windup than controls, and the chronic SCI subgroup mainly displayed higher pain windup. Conclusions The reduced PPDT found above lesion suggests the presence of CS in SCI. However, findings regarding SCI subgroup comparison did not support our hypothesis that more medication leads to increased CS. Implications The development of CS may complicate diagnosis and pain treatment following SCI. Prospective studies of SCI with a healthy control group are needed.

Objective Assessment of Lingual Nerve Microsurgical Reconstruction.

Lingual nerve (LN) injury is one of the most serious consequences of oral surgery. Prompt microsurgical reconstruction of the nerve can alleviate most of those symptoms leading to satisfactory functional recovery.Thirty-five patients with partial to complete LN injury underwent surgery in the period between January 2006 and May 2015. All patients underwent a preoperative clinical and neurological evaluation with the assessment of lingual tactile and pain sensory thresholds and masseteric inhibitory reflex.All patients underwent explorative surgery and direct microneurorrhaphy of distal and proximal stumps in case of complete lesion, while the removal of traumatic neuroma and the following microneurorrhaphy of distal and proximal stumps of the injured nerve was performed in case of incomplete lesion. Nerve grafting has always been avoided because of distal stump mobilization obtained by severing the submandibular branch of the LN.All patients but 1 exhibited good recovery of tongue sensation, never complete, both clinically and electrophysiologically: recovery of the excitability of masseteric inhibitory reflex suppression components SP1 and SP2 was observed, often with increased latencies but consistent with a functional recovery.All patients feeling pain preoperatively experienced complete relief of algic symptoms.The early microsurgical approach is the most suitable choice for the treatment of LN injuries.

Quantitative sensory testing in elderly: longitudinal study.

To evaluate elderly patients in a geriatric service, along with their sensory characteristics and their association with clinical aspects. This was a descriptive longitudinal study. We enrolled 36 healthy participants of both sexes in this study. The following instruments were used and evaluations performed: clinical evaluation, Mini-Mental State Exam, and quantitative sensory testing. During the follow-up, there was reduction of mean corpuscular volume at each evaluation (p < 0.001) and significant increase in mean corpuscular hemoglobin concentration (p < 0.001). There was an increase of the olfactory (p < 0.001), salty (p = 0.024), sour (p = 0.020), bitter (p = 0.001), facial cold (p = 0.019), hand cold (p = 0.004), facial tactile (p < 0.001), hand tactile (p = 0.012) and facial vibration (p = 0.018) thresholds. Previous existing morbidities were associated with sensitivity changes in the individuals in this sample. This longitudinal study suggests that the loss of sensitivity with aging may be associated with the presence of morbidities in elders.

Cathodal tDCS on the motor area decreases the tactile threshold of the distal pulp of the hallux

Transcranial direct current stimulation (tDCS) has been reported to modulate cortical excitability. Most studies on this topic addressed the modulation effects of tDCS on the upper extremities. Foot-sole tactile sensation is essential to gait, but little is known about the effect of tDCS on sensory function in the foot area. Here we administered tDCS to 10 healthy adults, and we observed that the modulation effects of cathodal tDCS on the left motor area led to a decrease in the tactile threshold of the left center of the distal pulp of the hallux. This effect was not observed in the sham condition. In addition, the subjects' vigilance levels were not changed between before and after the tDCS. These results suggest that sensation on the sole of the left foot could be modulated by cathodal tDCS on the left motor area.