Sensory Thresholds Research Articles

Application of sensory nerve quantitative tests to analyze the subtypes of motor disorders in Parkinson's disease.

This study investigated the sensory nerve function in people with different subtypes of Parkinson's disease (PD), which included the tremor-dominant (TD) group (n = 30), postural instability and gait disorder (PIGD) group (n = 33), and healthy-controls (HC) group (n = 33). Sural nerve's current perception threshold (CPT) and pain tolerance threshold (PTT) in both feet were measured at different frequencies. Results were evaluated using the mini-mental state examination (MMSE), Hoehn Yahr scale (H-Y) , and 3-meter timed-up-and-go-test (TUGT). The MMSE scores of the TD and HC groups were higher than those of the PIGD group (TD < HC). The 3-meter TUGT scores of the PIGD group were higher than theTD and HC groups (TD > HC). The PIGD patients experienced a significantly shorter disease duration and higher H-Y score than the TD patients ( P < 0.05). The values of 2 KHz CPT of left-side (CPTL), 2KHz CPT of right-side (CPTR), and 5 Hz CPTR in the PIGD group were significantly higher compared to the TD and HC groups ( P < 0.05, Bonferroni correction). Additionally, the values of 250 Hz CPTL, 5 Hz CPTL, 250 Hz CPTR, 2 kHz PTT of left-side (PTTL), 250 Hz PTTL, and 5 Hz PTTL in the PIGD group were significantly elevated relative to the TD group ( P < 0.05, Bonferroni correction). Distinctive current threshold perception and PTT of the sural nerve can be observed in patients with varying PD subtypes, and sensory nerve conduction threshold electrical diagnostic testing can detect these discrepancies in sensory nerve function.

Constipated patients with functional defecatory disorder have secondary rectal hyposensitivity due to altered rectal biomechanics.

Rectal hyposensitivity (RH) is common in constipation and often coexists with functional defecatory disorder (FDD). Rectal sensory thresholds are routinely evaluated with the anorectal manometry probe; however, the gold standard for the assessment of rectal sensitivity is with a barostat, use of which is limited by time constraints and availability. A novel rapid barostat bag (RBB) may facilitate measurements of rectal sensitivity. The aim is to evaluate the relationship between RH (measured by the RBB) and FDD (defined as any minor disorder of rectoanal coordination by the London classification) in constipated patients. Consecutive constipated patients referred for anorectal function testing underwent anorectal manometry with the 3D-HDAM probe as well as rectal sensation testing with the RBB pump. RH was defined by volume to first sensation >30%, urge to defecate >80%, or discomfort >100% (normalized to rectal capacity). Fifty-three percent of constipated patients had RH. Patients with FDD had a significantly increased volume to first sensation (134.5mL vs 102.0, P=0.02), urge to defecate (187.0mL vs 149.0, P=0.04), and rectal capacity (253.5mL vs 209.0, P=0.04) compared to constipated patients without FDD. There was no difference in normalized sensory thresholds (percent of rectal capacity) nor the prevalence of hyposensitivity to each sensory threshold nor overall hyposensitivity. Patients with FDD, when measured with the RBB, have increased sensory thresholds on volumetric distension, but RH was not observed when sensory threshold volume were normalized to rectal capacity. This may reflect "secondary" RH due to altered rectal biomechanics.

Definition of sensory and instrumental thresholds of acceptability for selection of cassava genotypes with improved boiling properties.

Consumers of boiled cassava in Africa, Latin America and Asia use specific preference criteria to evaluate its cooking quality, in terms of texture, colour and taste. To improve adoption rates of improved cassava varieties intended for consumption after boiling, these preference criteria need to be determined, quantified and integrated as post-harvest quality traits in the target product profile of boiled cassava, so that breeding programs may screen candidate varieties based on both agronomic traits and consumer preference traits. Surveys of various end-user groups identified seven priority quality attributes of boiled cassava covering root preparation, visual aspect, taste and texture. Three populations of contrasted cassava genotypes, from good-cooking to bad-cooking, in three countries (Uganda, Benin, Colombia) were then characterized according to these quality attributes by sensory quantitative descriptive analysis (QDA) and by standard instrumental methods. Consumers' preferences of the texture attributes mealiness and hardness were also determined. By analysis of correlations, the consumers' preferences scores were translated into thresholds of acceptability in terms of QDA scores, then in terms of instrumental measurements (water absorption during boiling and texture analysis). The thresholds of acceptability were used to identify among the Colombian and Benin populations promising genotypes for boiled cassava quality. This work demonstrates the steps of determining priority quality attributes for boiled cassava and establishing their corresponding quantitative thresholds of acceptability. The information can then be included in boiled cassava target product profiles used by cassava breeders, for better selection and adoption rates of new varieties. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Defecatory disorders are a common cause of chronic constipation in Parkinson disease.

Up to 50% of patients with Parkinson disease have constipation (PD-C), but the prevalence of defecatory disorders caused by rectoanal dyscoordination in PD-C is unknown. We aimed to compare anorectal function of patients with PD-C versus idiopathic chronic constipation (CC). Anorectal pressures, rectal sensation, and rectal balloon expulsion time (BET) were measured with high-resolution anorectal manometry (HR-ARM) in patients with PD-C and control patients with CC, matched for age and sex. We identified 97 patients with PD-C and 173 control patients. Eighty-six patients with PD-C (89%) had early PD, and 39 (40%) had a defecatory disorder, manifest by a prolonged rectal balloon expulsion time (37 patients) or a lower rectoanal pressure difference during evacuation (2 patients). PD-C patients with a prolonged BET had a greater anal resting pressure (p = 0.02), a lower rectal pressure increment (p = 0.005), greater anal pressure (p = 0.047), and a lower rectoanal pressure difference during evacuation (p < 0.001). Rectal sensory thresholds were greater in patients with abnormal BET. In the multivariate model comparing CC and PD-C (AUROC = 0.76), PD-C was associated with a lower anal squeeze increment (odds ratio [OR] for PD-C, 0.93 [95% CI, 0.91-0.95]), longer squeeze duration (OR, 1.05 [95% CI, 1.03-1.08]), lower rectal pressure increment (OR per 10 mm Hg, 0.72 [95% CI, 0.66-0.79]), and negative rectoanal gradient during evacuation (OR per 10 mm Hg, 1.16 [95% CI, 1.08-1.26]). Compared with CC, PD-C was characterized by impaired squeeze pressure, longer squeeze duration, lower increase in rectal pressure, and a more negative rectoanal gradient during evacuation.

The Impact of the Gender on the Pulp Vitality Testing for the Various Types of the Conducting Media: An Original Research

ABSTRACT Introduction: To identify gender-based differences in pulpal sensory thresholds in human teeth utilizing various conducting media. Materials and Methods: The study involved 50 participants of both genders equally distributed. The maxillary central incisors were the teeth selected for the intervention. The three conducting media that were put to the test were Colgate Sensitive Pro-Relief Enamel Repair Toothpaste (CS), Himalaya herbals sensitivity toothpaste (HS), and Lignox 2% gel (LG). Subject’s sensory threshold readings as well as the Visual analogue scale (VAS) scores were noted at the tiniest sensation they experienced. Following an ANOVA, a post hoc analysis was performed to confirm the significance between the three media. Results: Lox 2% Jelly significantly reduced sensory threshold values compared to the other conducting media (P &lt; 0.001). Comparing the sensory threshold values of the sexes showed that men have greater values. Male and female readings differed significantly in the Lox 2% Jelly group (P = 0.021), whereas Colgate Sensitive Pro-Relief Enamel Repair Toothpaste, Himalaya herbals sensitivity toothpaste (P &lt; 0.001) groups showed highly significant variances. All the three conducting media had a highly significant variance for the VAS scores. (P &lt; 0.001). Conclusion: The conducting material used and gender affect the pulpal sensory thresholds to electric impulses produced by EPT.

Abstract 30: Pharyngeal Electric Stimulation: The Initial U.S. Experience With a Novel Device for Treatment of Severe Dysphagia After Stroke

Background: Based on over 20 years of international research, FDA recently granted De Novo classification to the Phagenyx® Neurostimulation System for pharyngeal electrical stimulation (PES) for patients with severe dysphagia post stroke. Subjects &amp; Methods: We report on the design and outcomes of the first U.S. post market multi-center experience with the Phagenyx® Neurostimulation System (Phagenesis Limited, Manchester, UK). Eligible patients were determined to have severe dysphagia post-stroke (ischemic or hemorrhagic) by the treating stroke neurologists (MD) and standard assessments by Speech-Language Pathologists (SLPs). Treatment was implemented in addition to standard of care during hospitalization with institutional informed consents obtained prior to treatment. PES stimulation levels were optimized for each patient and each treatment through sensory threshold and tolerance testing by the SLPs. This was followed by a fixed 10 minute treatment session. The treatment regimen was: 1 treatment per day, 10 min/day x 3 days with interim speech therapy reassessment. Treatment could be extended up to 3 additional treatments for a total of 6 treatments if deemed necessary by medical team. SLPs monitored for adverse events during the optimization and treatment. Results: PES was administered to a minimum of 5 patients at each participating institution during the initial implementation. An instrumental assessment was completed at the conclusion of the treatment period as indicated, showing outcomes that ranged from improved secretion management and diet advancement, to swallow restoration. Patient experiences and suggestions were captured and will be presented. Conclusions: A novel FDA-approved PES device for treatment of severe dysphagia shows a potential to be safely tolerated with the magnitude of swallowing improvement and restoration similar to the pivotal trials conducted overseas. Final results of the multi-center study will be presented at the meeting.

Quantifying sensory thresholds along the migraine cycle: An exploratory longitudinal study.

To date, a number of studies on migraine have cross-sectionally evaluated sensory sensitivity with aversion thresholds/scores along the migraine cycle, reporting a decreased tolerance to sensory stimuli in different sensory modalities. Our hypothesis was that patients with migraine would exhibit heightened sensitivity to sound, light, touch and smell on days where they reported greater headache intensity. This is an exploratory, longitudinal study, carried out over the course of 27 days. Aversion thresholds or scores to sound, light, touch and smell were quantified in six patients with migraine (11.33 ± 6.53 headache days/month). Patients reported an increased sensitivity to light (padj = 0.0297), touch (padj = 0.0077), and smell (padj = 0.0201) on days with higher headache intensity. However, a greater sensitivity to sound on days with higher headache intensity was only reported when anxiety levels were high (padj = 1.4e-06). Interestingly, variable levels of tolerance to bothersome light over time can also influence the correlation between light sensitivity and headache intensity (padj = 1.4e-06). Based on the present findings, future longitudinal studies evaluating sensory threshold changes along the migraine cycle in patients with migraine should account for the increased tolerance to bothersome light over time as well as the effect of anxiety on auditory sensitivity.

Distinguishing fibromyalgia syndrome from small fiber neuropathy: a clinical guide.

Fibromyalgia syndrome (FMS) and small fiber neuropathy (SFN) are distinct pain conditions that share commonalities and may be challenging as for differential diagnosis. To comprehensively investigate clinical characteristics of women with FMS and SFN to determine clinically applicable parameters for differentiation. We retrospectively analyzed medical records of 158 women with FMS and 53 with SFN focusing on pain-specific medical and family history, accompanying symptoms, additional diseases, and treatment. We investigated data obtained using standardized pain, depression, and anxiety questionnaires. We further analyzed test results and findings obtained in standardized small fiber tests. FMS patients were on average ten years younger at symptom onset, described higher pain intensities requiring frequent change of pharmaceutics, and reported generalized pain compared to SFN. Pain in FMS was accompanied by irritable bowel or sleep disturbances, and in SFN by paresthesias, numbness, and impaired glucose metabolism (P < 0.01 each). Family history was informative for chronic pain and affective disorders in FMS (P < 0.001) and for neurological disorders in SFN patients (P < 0.001). Small fiber pathology in terms of skin denervation and/or thermal sensory threshold elevation was present in 110/158 (69.7 %) FMS patients and 39/53 (73.6 %) SFN patients. FMS patients mainly showed proximally reduced skin innervation and higher corneal nerve branch densities (p<0.001) whereas SFN patients were characterized by reduced cold detection and prolonged electrical A-delta conduction latencies (P < 0.05). Our data show that FMS and SFN differ substantially. Detailed pain, drug and family history, investigating blood glucose metabolism, and applying differential small fiber tests may help to improve diagnostic differentiation and targeted therapy.

Characteristics of bone metabolism in the male patients with diabetic neuropathy.

This study aimed to evaluate the characteristics of bone metabolism and fracture risk in the type 2 diabetes mellitus (T2DM) patients with distal symmetric polyneuropathy (DSPN). A total of 198 T2DM individuals were recruited from January 2017 to December 2020. Patients with DSPN were evaluated by strict clinical and sensory thresholds. Biochemical parameters and bone mineral density (BMD) were measured. The BMD, bone turnover markers, and probability of fracture were compared between two groups, and the factors related to BMD and probability of hip fracture in 10 years were further explored. Compared with type 2 diabetes mellitus without distal symmetric polyneuropathy (T2DN-) patients, type 2 diabetes mellitus with distal symmetric polyneuropathy (T2DN+) patients had lower level of cross-linked C-telopeptide (CTX) (0.32 ± 0.19 vs 0.38 ± 0.21 ng/mL, p = 0.038) and higher level of bone-specific alkaline phosphatase (BALP) (15.28 ± 5.56 vs 12.58 ± 4.41 μg/mL, p = 0.003). T2DN+ patients had higher BMD of lumbar L1-L4 (1.05 ± 0.19 vs 0.95 ± 0.37, p = 0.027) and higher probability of hip fracture (0.98 ± 0.88 vs 0.68 ± 0.63, p = 0.009) as compared to T2DN- individuals. Univariate correlation analysis showed that BALP level (coefficient (coef) = -0.054, p = 0.038), CTX level (coef = -2.28, p = 0.001), and hip fracture risk (coef = -1.02, p < 0.001) were negatively related to the BMD of L1-L4. As for the risk of hip fracture evaluated by WHO Fracture Risk Assessment Tool (FRAX), age (coef = 0.035, p < 0.001), use of insulin (coef = 0.31, p =0.015), and levels of BALP (coef = 0.031, p = 0.017) and CTX (coef = 0.7, p = 0.047) were positively related to the risk of hip fracture. Multivariate regression analysis showed that CTX level (coef = -1.41, p = 0.043) was still negatively related to BMD at the lumbar spine. This study indicates that T2DM patients with DSPN have special bone metabolism represented by higher BALP level and lower CTX level which may increase BMD at the lumbar spine.

Exposure limits for indoor volatile substances concerning the general population: The role of population-based differences in sensory irritation of the eyes and airways for assessment factors.

Assessment factors (AFs) are essential in the derivation of occupational exposure limits (OELs) and indoor air quality guidelines. The factors shall accommodate differences in sensitivity between subgroups, i.e., workers, healthy and sick people, and occupational exposure versus life-long exposure for the general population. Derivation of AFs itself is based on empirical knowledge from human and animal exposure studies with immanent uncertainty in the empirical evidence due to knowledge gaps and experimental reliability. Sensory irritation in the eyes and airways constitute about 30-40% of OELs and is an abundant symptom in non-industrial buildings characterizing the indoor air quality and general health. Intraspecies differences between subgroups of the general population should be quantified for the proposal of more 'empirical' based AFs. In this review, we focus on sensitivity differences in sensory irritation about gender, age, health status, and vulnerability in people, based solely on human exposure studies. Females are more sensitive to sensory irritation than males for few volatile substances. Older people appear less sensitive than younger ones. However, impaired defense mechanisms may increase vulnerability in the long term. Empirical evidence of sensory irritation in children is rare and limited to children down to the age of six years. Studies of the nervous system in children compared to adults suggest a higher sensitivity in children; however, some defense mechanisms are more efficient in children than in adults. Usually, exposure studies are performed with healthy subjects. Exposure studies with sick people are not representative due to the deselection of subjects with moderate or severe eye or airway diseases, which likely underestimates the sensitivity of the group of people with diseases. Psychological characterization like personality factors shows that concentrations of volatile substances far below their sensory irritation thresholds may influence the sensitivity, in part biased by odor perception. Thus, the protection of people with extreme personality traits is not feasible by an AF and other mitigation strategies are required. The available empirical evidence comprising age, lifestyle, and health supports an AF of not greater than up to 2 for sensory irritation. Further, general AFs are discouraged for derivation, rather substance-specific derivation of AFs is recommended based on the risk assessment of empirical data, deposition in the airways depending on the substance's water solubility and compensating for knowledge and experimental gaps. Modeling of sensory irritation would be a better 'empirical' starting point for derivation of AFs for children, older, and sick people, as human exposure studies are not possible (due to ethical reasons) or not generalizable (due to self-selection). Dedicated AFs may be derived for environments where dry air, high room temperature, and visually demanding tasks aggravate the eyes or airways than for places in which the workload is balanced, while indoor playgrounds might need other AFs due to physical workload and affected groups of the general population.

How to make calibration less painful-A proposition for an automatic, reliable and time-efficient procedure.

In behavioral and neurophysiological pain studies, multiple types of calibration methods are used to quantify the individual pain sensation stimuli. Often, studies lack a detailed calibration procedure description, data linearity, and quality quantification and omit required control for sex pain differences. This hampers study repetition and interexperimental comparisons. Moreover, typical calibration procedures require a high number of stimulations, which may cause discomfort and stimuli habituation among participants. To overcome those shortcomings, we present an automatic calibration procedure with a novel stimuli estimation method for intraepidermal stimulation. We provide an in-depth data analysis of the collected self-reports from 70 healthy volunteers (37 males) and propose a method based on a dynamic truncated linear regression model (tLRM). We compare its estimates for the sensation (t) and pain (T) thresholds and mid-pain stimulation (MP), with those calculated using traditional estimation methods and standard linear regression models. Compared to the other methods, tLRM exhibits higher R2 and requires 36% fewer stimuli applications and has significantly higher t intensity and lower T and MP intensities. Regarding sex differences, t and T were found to be lower for females compared to males, regardless of the estimation method. The proposed tLRM method quantifies the calibration procedure quality, minimizes its duration and invasiveness, and provides validation of linearity between stimuli intensity and subjective scores, making it an enabling technique for further studies. Moreover, our results highlight the importance of control for sex in pain studies.

Repeated boat noise exposure damages inner ear sensory hair cells and decreases hearing sensitivity in Atlantic croaker (Micropogonias undulatus).

Anthropogenic noise is becoming a major underwater pollutant because of rapidly increasing boat traffic worldwide. But its impact on aquatic organisms remains largely unknown. Previous studies have focused mainly on high-frequency and impulsive noises (i.e. sonar); however, boat noise is more pervasive, continuous, and its highest intensity and component frequencies overlap the auditory bandwidth of most fishes. We assessed the impacts of boat noise on saccular sensory hair cell density and hearing thresholds of a soniferous species, Atlantic croaker (Micropogonias undulatus). In two laboratory experiments, individuals were subjected to simulated boat noise: a single 15-min exposure and 3days of intermittent noise (simulating passing vessels). Immediately after both experiments, fish were either (1) tested for hearing sensitivity with auditory evoked potential (AEP) tests or (2) euthanized for fluorescent phalloidin and TUNEL labeling for hair cell density counts. Relative to controls, no differences were observed in auditory thresholds nor hair cell density between individuals subjected to a single 15-min noise exposure. However, fish from the 3-day experiment showed decreased sensory hair cell density, increased apoptotic cells, and higher hearing thresholds than control fish at 300, 800 and 1000 Hz. Our results demonstrate that impacts from boat noise depend upon the duration and frequency of exposure. For a species reliant on vocalization for communication, these impacts may hinder spawning success, increase predation risks and significantly alter the ecosystem.

Changes in sensitivity and hedonic rating to transcutaneous electrical nerve stimulation following COVID-19

COVID-19 affects not only the respiratory system but also other biological systems such as the nervous system. Usually, these changes are reported based on the patient's subjective description. The aim of our study, therefore, was to objectively determine the effect that the SARS-CoV-2 virus and COVID-19 disease has on sensory threshold and the hedonic and subjective perception of an electrical stimulus. The sensory threshold was tested on the inner forearm by applying non-invasive transcutaneous electrical nerve stimulation (TENS) with 100 Hz and 100 µs parameters and a biphasic current waveform. The study involved 211 participants, aged 22–79 years, with a mean age of 56.9 ± 12.1 years. There were 131 subjects in the COVID group, while the NON-COVID group, the control group, was matched to the COVID group in terms of gender, age, body mass index and presence of chronic diseases. The research was carried out in 2022. Sensory sensitivity was highest in the group that had suffered with COVID-19. The median sensory sensitivity was 11 mA in the COVID group and 14 mA (p < 0.001) in the NON-COVID group, however, the current sensitivity threshold decreased over time (R = 0.52, p < 0.001). Post COVID-19, the electrical stimulus was more often perceived as unpleasant: COVID versus NON-COVID (23% vs. 3%, p < 0.001) and as a different sensation to tingling (27% vs. 2%, p < 0.001). Post-COVID-19 patients have a lower sensory threshold, the electrical stimulus is more often described as unpleasant and in subjective feelings it is more often described as pinching. The differences between COVID and NON-COVID decrease with time since the onset of COVID symptoms.

MEASURE THE LEVEL OF SENSORY PROCESSING PROBLEM IN CHILDREN WITH AND WITH OUT AUTISM IN CLASSROOM ENVIRONMENT

Background of the Study: Sensory processing is the process in which all sensory stimuli integrate and enable person to respond according to the situation. There are number of sensory issues that either parents or teacher do not identify on early stages and various times it also cause behavioral issues or academic issues with in typical children too. The study aims to assess the sensory vulnerability of children with and without autism in the school environment and to identify the sensory issues. Methodology: This was a cross-sectional study conducted in Karachi, Pakistan. Total 86 children recruited and divided into two groups included typical and atypical children. Using a standardized questionnaire-SPM (sensory processing measure) distributed in schools and completed by teachers. Result: Autism affects both mainstream children and children with autism, with sensory process subscales showing significant differences p value (&lt; .005) for t- test. Autism children have higher sensory process vulnerability, particularly in social participation and praxis variables, compared to mainstream children’s. Conclusion: The study reveals that school initiates sensory stimuli, affecting children's vulnerability, even in special schools, despite providing structured environments for atypical children. Keyword: Perception, SPM, sensory responses, sensory threshold, autism, autistic disorder.

Perception of vibration threshold potential with tuning fork and pure tone audiometry assessment for early detection of diabetic polyneuropathy

Background: Diabetes mellitus (DM), a multisystem disorder, is a known etiological entity, leading to several neurological disorders. Among them, nervous system is more commonly affected. In most of the diabetic polyneuropathy cases, sensory symptoms involving both general and special senses predominate. Due to gradual and non-homogenous manifestations, it is not easy to detect its onset. Till now no accepted gold standard has been available for its assessment and diagnosis. In this study, changes in vibration perception threshold (VPT) at different frequencies and auditory perception threshold have been investigated in diabetes patients and healthy controls. Aims and objectives: Determination of perception threshold of a general sense-vibration sense and a special sense-hearing in normal human subjects and patients of DM and evaluation of perception threshold of the human sensory system by VPT test and pure tone audiometry (PTA) as a diagnostic, prognostic and research tool for diabetic neuropathy. Materials and Methods: A case–control study, conducted in the department of physiology at medical college, Kolkata, after obtaining approval by the institutional research and ethics committee on 100 cases and 40 control subjects. Testing of vibration sensitivity was performed with the help of tuning forks of frequencies of 128 Hz, 256 Hz, and 512 Hz. Assessment of auditory perception threshold was done by Siemens SD 28 diagnostic audiometer. Results: All data obtained by the methods described here are tabulated. Graphs and charts are drawn and analyzed by standard statistical methods using Statistical Packages for the Social Sciences (version-16) and MATLAB (version-9). A P &lt; 0.05 was considered as significant. A partial negative correlation was observed between the vibration sensitivity and fasting blood sugar and postprandial blood sugar level of the patient population of DM cases, with a “r” value (Pearson’s correlation coefficient was around −0.5. By PTA, it was found the percentage of rise in auditory threshold is around 92–93% in 8000 Hz frequency, and the results of the t-test yield a very highly significant difference (P &lt; 0.0001) between cases and controls. It was found that 128 Hz and 256 Hz vibration stimuli applied over maxillary prominence are highly sensitive and efficient tools for perception analysis. Pure tone auditory threshold evaluation showed preservation of the right-sided advantage of auditory sensitivity and frequency-dependent loss of hearing in the diabetic study population. Conclusion: Determination of perception threshold of vibration sense by tuning fork and auditory perception by PTA may be used as an effective, easily performed, and low-cost bedside and also outpatient department-based diagnostic tool in patients with DM.

The trilogy of human musk receptors: linking receptor activation, genotype, and sensory perception.

The scent of musk plays a unique role in the history of perfumery. Musk odorants comprise 6 diverse chemical classes and perception differences in strength and quality among human panelists have long puzzled the field of olfaction research. Three odorant receptors (OR) had recently been described for musk odorants: OR5AN1, OR1N2, and OR5A2. High functional expression of the difficult-to-express human OR5A2 was achieved by a modification of the C-terminal domain and the link between sensory perception and receptor activation for the trilogy of these receptors and their key genetic variants was investigated: All 3 receptors detect only musky smelling compounds among 440 commercial fragrance compounds. OR5A2 is the key receptor for the classes of polycyclic and linear musks and for most macrocylic lactones. A single P172L substitution reduces the sensitivity of OR5A2 by around 50-fold. In parallel, human panelists homozygous for this mutation have around 40-60-fold higher sensory detection threshold for selective OR5A2 ligands. For macrocyclic lactones, OR5A2 could further be proven as the key OR by a strong correlation between in vitro activation and the sensory detection threshold in vivo. OR5AN1 is the dominant receptor for the perception of macrocyclic ketones such as muscone and some nitromusks, as panelists with a mutant OR5A2 are still equally sensitive to these ligands. Finally, OR1N2 appears to be an additional receptor involved in the perception of the natural (E)-ambrettolide. This study for the first time links OR activation to sensory perception and genetic polymorphisms for this unique class of odorants.

Influence of pain prognosis and electrical stimulation modality on the amplitude of current elicited at sensory threshold in chronic lumbar pain sufferers

Influence of pain prognosis and electrical stimulation modality on the amplitude of current elicited at sensory threshold in chronic lumbar pain sufferers

Macleaya Extract versus Pregabalin Therapeutic Effectiveness for Neuropathic Pain in Dogs.

Dogs suffer from neuropathic pain due to several neurological disorders, particularly intervertebral disc disease. We aimed to identify alternative therapeutics for neuropathic pain relief in dogs by comparing the treatment efficacy of pregabalin and Macleaya extract against neuropathic pain from cervical spinal hyperesthesia caused by intervertebral disc disease in dogs. We evaluated 10 dogs suffering from cervical intervertebral disc disease for neuropathic pain using the filament von Frey aesthesiometer (VFA). The dogs were randomly divided into two groups, G1 (n = 5) was treated with 4 mg/kg of pregabalin/12 hours orally for 14 days, and G2 (n = 5) was treated with 15 mg/kg Macleaya extract once daily orally for 14 days. To detect neuropathic pain, the VFA was used to measure the sensory threshold (ST) on days 0, 7, and 14. The results revealed decreases in all ST outcomes with no significant differences between the groups on day 14 posttreatment, as well as a decrease in the severity of neurological disease in both groups on day 7 posttreatment. No significant differences were detected in hematological and biochemical profiles (alanine aminotransferase (ALT), alkaline phosphatase (ALP), serum creatinine (SCR), urea nitrogen (BUN), and total protein (TP)) in both groups between pre- and posttreatment were not significantly different. The Macleaya extract can reduce neuropathic pain in a similar pattern to pregabalin. Macleaya extract may be effective for the treatment of neuropathic pain in dogs with spinal hyperesthesia.

Experiments on the peculiar region and threshold of oppressive or vibratory sensation caused by low-frequency pure tones

Experiments on the peculiar region and threshold of oppressive or vibratory sensation caused by low-frequency pure tones

The thermal sensation threshold and its reliability induced by the exposure to 28 GHz millimeter-wave.

The application of 28 GHz millimeter-wave is prevalent owing to the global spread of fifth-generation wireless communication systems. Its thermal effect is a dominant factor which potentially causes pain and tissue damage to the body parts exposed to the millimeter waves. However, the threshold of this thermal sensation, that is, the degree of change in skin temperature from the baseline at which the first subjective response to the thermal effects of the millimeter waves occurs, remains unclear. Here, we investigated the thermal sensation threshold and assessed its reliability when exposed to millimeter waves. Twenty healthy adults were exposed to 28 GHz millimeter-wave on their left middle fingertip at five levels of antenna input power: 0.2, 1.1, 1.6, 2.1, and 3.4 W (incident power density: 27-399 mW/cm2). This measurement session was repeated twice on the same day to evaluate the threshold reliability. The intraclass correlation coefficient (ICC) and Bland-Altman analysis were used as proxies for the relative and absolute reliability, respectively. The number of participants who perceived a sensation during the two sessions at each exposure level was also counted as the perception rate. Mean thermal sensation thresholds were within 0.9°C-1.0°C for the 126-399 mW/cm2 conditions, while that was 0.2°C for the 27 mW/cm2 condition. The ICCs for the threshold at 27 and 126 mW/cm2 were interpreted as poor and fair, respectively, while those at higher exposure levels were moderate to substantial. Apart from a proportional bias in the 191 mW/cm2 condition, there was no fixed bias. All participants perceived a thermal sensation at 399 mW/cm2 in both sessions, and the perception rate gradually decreased with lower exposure levels. Importantly, two-thirds of the participants answered that they felt a thermal sensation in both or one of the sessions at 27 mW/cm2, despite the low-temperature increase. These results suggest that the thermal sensation threshold is around 1.0°C, consistent across exposure levels, while its reliability increases with higher exposure levels. Furthermore, the perception of thermal sensation may be inherently ambiguous owing to the nature of human perception.