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Neuron Aug 2013The somatosensory system decodes a wide range of tactile stimuli and thus endows us with a remarkable capacity for object recognition, texture discrimination,... (Review)
Review
The somatosensory system decodes a wide range of tactile stimuli and thus endows us with a remarkable capacity for object recognition, texture discrimination, sensory-motor feedback and social exchange. The first step leading to perception of innocuous touch is activation of cutaneous sensory neurons called low-threshold mechanoreceptors (LTMRs). Here, we review the properties and functions of LTMRs, emphasizing the unique tuning properties of LTMR subtypes and the organizational logic of their peripheral and central axonal projections. We discuss the spinal cord neurophysiological representation of complex mechanical forces acting upon the skin and current views of how tactile information is processed and conveyed from the spinal cord to the brain. An integrative model in which ensembles of impulses arising from physiologically distinct LTMRs are integrated and processed in somatotopically aligned mechanosensory columns of the spinal cord dorsal horn underlies the nervous system's enormous capacity for perceiving the richness of the tactile world.
Topics: Animals; Mechanoreceptors; Physical Stimulation; Sensory Receptor Cells; Sensory Thresholds; Touch
PubMed: 23972592
DOI: 10.1016/j.neuron.2013.07.051 -
Journal of Vision Jul 2023To investigate the mechanisms underlying elongated spatial summation with a pattern-masking paradigm, we measured the contrast detection thresholds for elongated Gabor...
To investigate the mechanisms underlying elongated spatial summation with a pattern-masking paradigm, we measured the contrast detection thresholds for elongated Gabor targets situated at 3° eccentricity to either the left or right of the fixation and elongated along an arc of the same radius to access homogeneous retinal sensitivity. The mask was a ring with a Gabor envelope of the same 3° center radius containing either a concentric (iso-orientation mask) or a radial (orthogonal mask) modulation. The task of the observer was to indicate whether the target in each trial was on the left or the right of the fixation. With orthogonal or low contrast iso-orientation masks, target thresholds first decreased with size with slope -1 on log-log coordinates until the target length reached 45' (specified as the half-height full-width of the Gabor envelope) and then further decreased according to a slope of -1/2, the latter being the signature of an ideal summation process. When the contrast of the iso-orientation mask was sufficiently high, however, the target thresholds, while still showing a -1 slope up to ∼10', asymptoted up to about 50' length, suggesting that the presence of the mask eliminated the ideal summation regime. Beyond about 50', the data approximated another -1 slope decrease in threshold, suggesting the existence of an extra-long channel that is not revealed by the conventional spatial summation paradigm. The full results could be explained by a divisive inhibition model, in which second-order filters sum responses across local oriented channels, combined with a single extra-long filter at least 300' in extent. In this model, the local filter response is given by the linear excitation of the local channels raised to a power, and scaled by divisive inhibition from all channels in the neighborhood. With the high-contrast iso-orientation masks, such divisive inhibition swamps the response to eliminate the ideal summation regime until the stimulus is long enough to activate the extra-long filter.
Topics: Humans; Contrast Sensitivity; Sensory Thresholds; Perceptual Masking; Inhibition, Psychological
PubMed: 37505916
DOI: 10.1167/jov.23.7.17 -
European Journal of Pain (London,... Sep 2020Orofacial quantitative sensory testing (QST) is an increasingly valuable psychophysical tool for evaluating neurosensory disorders of the orofacial region. Here, we... (Review)
Review
BACKGROUND AND OBJECTIVE
Orofacial quantitative sensory testing (QST) is an increasingly valuable psychophysical tool for evaluating neurosensory disorders of the orofacial region. Here, we aimed to evaluate the current evidence regarding this testing method and to discuss its future clinical potential.
DATA TREATMENT
We conducted a literature search in Medline, Embase and Scopus for English-language articles published between 1990 and 2019. The utilized search terms included QST, quantitative, sensory testing and neurosensory, which were combined using the AND operator with the terms facial, orofacial, trigeminal, intraoral and oral.
RESULTS
Our findings highlighted many methods for conducting QST-including method of levels, method of limits and mapping. Potential stimuli also vary, and can include mechanical or thermal stimulation, vibration or pinprick stimuli. Orofacial QST may be helpful in revealing disease pathways and can be used for patient stratification to validate the use of neurosensory profile-specific treatment options. QST is reportedly reliable in longitudinal studies and is thus a candidate for measuring changes over time. One disadvantage of QST is the substantial time required; however, further methodological refinements and the combination of partial aspects of the full QST battery with other tests and imaging methods should result in improvement.
CONCLUSIONS
Overall, orofacial QST is a reliable testing method for diagnosing pathological neurosensory conditions and assessing normal neurosensory function. Despite the remaining challenges that hinder the use of QST for everyday clinical decisions and clinical trials, we expect that future improvements will allow its implementation in routine practice.
Topics: Humans; Pain Threshold; Sensory Thresholds; Vibration
PubMed: 32557971
DOI: 10.1002/ejp.1611 -
Vision Research Sep 2013Contrast sensitivity defines the threshold between the visible and invisible, which has obvious significance for basic and clinical vision science. Fechner's 1860 review...
Contrast sensitivity defines the threshold between the visible and invisible, which has obvious significance for basic and clinical vision science. Fechner's 1860 review reported that threshold contrast is 1% for a remarkably wide range of targets and conditions. While printed charts are still in use, computer testing is becoming more popular because it offers efficient adaptive measurement of threshold for a wide range of stimuli. Both basic and clinical studies usually want to know fundamental visual capability, regardless of the observer's subjective criterion. Criterion effects are minimized by the use of an objective task: multiple-alternative forced-choice detection or identification. Having many alternatives reduces the guessing rate, which makes each trial more informative, so fewer trials are needed. Finally, populations who may experience crowding or target confusion should be tested with one target at a time.
Topics: Contrast Sensitivity; Humans; Psychometrics; Sensory Thresholds; Vision Tests; Vision, Low
PubMed: 23643905
DOI: 10.1016/j.visres.2013.04.015 -
PloS One 2014The effect of acupuncture on sensory perception has never been systematically reviewed; although, studies on acupuncture mechanisms are frequently based on the idea that... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
The effect of acupuncture on sensory perception has never been systematically reviewed; although, studies on acupuncture mechanisms are frequently based on the idea that changes in sensory thresholds reflect its effect on the nervous system.
METHODS
Pubmed, EMBASE and Scopus were screened for studies investigating the effect of acupuncture on thermal or mechanical detection or pain thresholds in humans published in English or German. A meta-analysis of high quality studies was performed.
RESULTS
Out of 3007 identified articles 85 were included. Sixty five studies showed that acupuncture affects at least one sensory threshold. Most studies assessed the pressure pain threshold of which 80% reported an increase after acupuncture. Significant short- and long-term effects on the pressure pain threshold in pain patients were revealed by two meta-analyses including four and two high quality studies, respectively. In over 60% of studies, acupuncture reduced sensitivity to noxious thermal stimuli, but measuring methods might influence results. Few but consistent data indicate that acupuncture reduces pin-prick like pain but not mechanical detection. Results on thermal detection are heterogeneous. Sensory threshold changes were equally frequent reported after manual acupuncture as after electroacupuncture. Among 48 sham-controlled studies, 25 showed stronger effects on sensory thresholds through verum than through sham acupuncture, but in 9 studies significant threshold changes were also observed after sham acupuncture. Overall, there is a lack of high quality acupuncture studies applying comprehensive assessments of sensory perception.
CONCLUSIONS
Our findings indicate that acupuncture affects sensory perception. Results are most compelling for the pressure pain threshold, especially in pain conditions associated with tenderness. Sham acupuncture can also cause such effects. Future studies should incorporate comprehensive, standardized assessments of sensory profiles in order to fully characterize its effect on sensory perception and to explore the predictive value of sensory profiles for the effectiveness of acupuncture.
Topics: Acupuncture Therapy; Databases, Bibliographic; Humans; Pain Threshold
PubMed: 25502787
DOI: 10.1371/journal.pone.0113731 -
Veterinary Journal (London, England :... Apr 2019It is assumed that Cavalier King Charles spaniels with Chiari-like malformation and syringomyelia experience central neuropathic pain. An association between spinal cord...
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.
Topics: Animals; Behavior, Animal; Case-Control Studies; Dog Diseases; Dogs; Female; Magnetic Resonance Imaging; Male; Mechanotransduction, Cellular; Pain; Prospective Studies; Sensory Thresholds; Spinal Cord; Syringomyelia
PubMed: 30902196
DOI: 10.1016/j.tvjl.2019.01.011 -
Acta Paediatrica (Oslo, Norway : 1992) Sep 2019Early-life atypical sensory functioning and behavioural profiles are often associated with long-term developmental problems, especially in former preterm infants. We...
AIM
Early-life atypical sensory functioning and behavioural profiles are often associated with long-term developmental problems, especially in former preterm infants. We tested whether parenting style is associated with atypical sensory threshold or behavioural outcomes in preterm and term infants assessed during early childhood.
METHODS
We prospectively evaluated parenting style for a cohort of term and preterm infants who had previous assessments of sensory development and behaviour. We used standardised tools to evaluate parenting style, sensory neurological threshold at one year, and internalising and externalising behavioural tendencies at two years. Covariates included gestational age, sex and maternal education.
RESULTS
For the entire cohort (n = 82), children of more permissive parents were 2.7 times more likely to demonstrate abnormal sensory neurological thresholds compared to children of parents with less permissive styles (CI: 1.4-4.9). More permissive parenting scores were also associated with 2.4 times increased internalising (CI: 1.3-4.2) and 3.0 times increased externalising (CI: 1.6-5.6) tendencies. In the preterm group only, higher authoritative parenting scores were associated with fewer behavioural problems.
CONCLUSION
Permissive parenting is associated with worse infant sensory and behavioural outcomes. Authoritative parenting is associated with fewer behavioural problems in preterm children. Modification of parenting style may improve sensory development and behavioural outcomes.
Topics: Authoritarianism; Female; Humans; Infant, Newborn; Infant, Premature; Male; Parenting; Permissiveness; Prospective Studies; Sensory Thresholds
PubMed: 30790352
DOI: 10.1111/apa.14761 -
Pediatric Rheumatology Online Journal Aug 2022Juvenile Idiopathic Arthritis (JIA) is a childhood-rheumatic disease with pain as a major early complaint, and in 10-17% pain remains a major symptom. Very few data...
OBJECTIVE
Juvenile Idiopathic Arthritis (JIA) is a childhood-rheumatic disease with pain as a major early complaint, and in 10-17% pain remains a major symptom. Very few data exist on sensory threshold changes at the knee in JIA, a location in which inflammation often manifests. We determined whether JIA is associated with sensory threshold changes at the knee by using Quantitative Sensory Testing (QST) and established reference values at the knee of children.
METHODS
Sixteen patients with JIA aged 9-18 years with one affected knee and a patient-reported pain by Visual Analog Scale (VAS) > 10 on a 0-100 scale, and 16 healthy controls completed the study and were included for the analysis. QST was assessed in compliance with the German Research Network on Neuropathic Pain (DFNS) standard. Disease severity was determined using Juvenile Disease Activity Score (JADAS. Perceived pain was assessed with a visual analogue scale(0-100). Feasibility of QST was tested in patients aged 6-9.
RESULTS
Under the age of 9, QST testing showed not to be feasible in 3 out of 5 JIA patients. Patients with JIA aged 9 and older reported an average VAS pain score of 54.3. QST identified a significant reduction in pressure pain threshold (PPT) and increase in cold detection threshold (CDT) compared to healthy controls. PPT is reduced in both the affected and the unaffected knee, CDT is reduced in the unaffected knee, not the affected knee.
CONCLUSION
In a Dutch cohort of Patients with JIA, QST is only feasible from 9 years and up. Also, sensory threshold changes at the knee are restricted to pressure pain and cold detection thresholds in Patients with JIA.
PERSPECTIVE
This article shows that in a Dutch population, the extensive QST protocol is only feasible in the age group from 9 years and older, and a reduced set of QST tests containing at least pressure pain thresholds and cold detection thresholds could prove to be better suited to the pediatric setting with arthritis.
Topics: Arthritis, Juvenile; Child; Feasibility Studies; Humans; Neuralgia; Pain Measurement; Pain Threshold; Sensory Thresholds
PubMed: 35945540
DOI: 10.1186/s12969-022-00715-5 -
Equine Veterinary Journal Jan 2021Quantitative sensory testing methods are now standard in the evaluation of sensory function in man, while few normal equine values have been reported.
BACKGROUND
Quantitative sensory testing methods are now standard in the evaluation of sensory function in man, while few normal equine values have been reported.
OBJECTIVES
The aim of this experimental study was (a) to define the tactile sensory, mechanical nociceptive and thermal nociceptive thresholds of the equine face; (b) to assess the effect of age, sex, stimulation site and shaving; (c) to evaluate the reliability of the methods and (d) to provide reference facial quantitative sensory testing values.
STUDY DESIGN
Method description.
METHODS
Thirty-four healthy Warmblood horses were used in the study. Six (tactile sensory threshold) and five (mechanical nociceptive and thermal nociceptive thresholds) areas of the left side of the face with clear anatomical landmarks were evaluated. Ten horses had two (mechanical nociceptive threshold) or three (tactile sensory and thermal nociceptive thresholds) of these areas shaved for another study. A linear Mixed model was used for data analysis.
RESULTS
All thresholds increased with age (tactile sensory threshold: by 0.90 g/y (CI = [0.12 g; 0.36 g]) P = .001; mechanical nociceptive threshold: by 0.25 N/y (CI = [0.13-0.36 N]) P = .000; thermal nociceptive threshold: by 0.2°C/y (CI = [0.055-0.361]) P = .008). Sex had no effect on thresholds (tactile sensory threshold: P = .1; mechanical nociceptive threshold: P = .09; thermal nociceptive threshold: P = .2). Stimulation site affected tactile sensory and mechanical nociceptive thresholds (P = .001 and P = .008), but not thermal nociceptive threshold (P = .9). Shaving had no significant effect on any of the thresholds (tactile sensory threshold: P = .06; mechanical nociceptive threshold: P = .08; thermal nociceptive threshold: P = .09).
MAIN LIMITATIONS
Only the left side was investigated and measurements were obtained on a single occasion.
CONCLUSIONS
Handheld quantitative sensory testing does not require shaving or clipping to provide reliable measurements. Stimulation over the nostril (tactile sensory threshold), temporomandibular joint (mechanical nociceptive threshold) and supraorbital foramen (thermal nociceptive threshold) resulted in the most consistent thresholds.
Topics: Animals; Horse Diseases; Horses; Hot Temperature; Pain; Reference Values; Reproducibility of Results; Sensory Thresholds
PubMed: 32306423
DOI: 10.1111/evj.13270 -
Biological Research For Nursing Jan 2018Chronic pain is a significant problem for patients with lower extremity injuries. While pain hypersensitivity has been identified in many chronic pain conditions, it is... (Comparative Study)
Comparative Study
BACKGROUND
Chronic pain is a significant problem for patients with lower extremity injuries. While pain hypersensitivity has been identified in many chronic pain conditions, it is not known whether patients with chronic pain following lower extremity fracture report pain hypersensitivity in the injured leg.
PURPOSE
To quantify and compare peripheral somatosensory function and sensory nerve activation thresholds in persons with chronic pain following lower extremity fractures with a cohort of persons with no history of lower extremity fractures.
METHOD
This was a cross-sectional study where quantitative sensory testing and current perception threshold testing were conducted on the injured and noninjured legs of cases and both legs of controls.
RESULTS
A total of 14 cases and 28 controls participated in the study. Mean time since injury at the time of testing for cases was 22.3 (standard deviation = 12.1) months. The warmth detection threshold ( p = .024) and nerve activation thresholds at 2,000 Hz ( p < .001) and 250 Hz ( p = .002), respectively, were significantly higher in cases compared to controls.
CONCLUSION
This study suggests that patients with chronic pain following lower extremity fractures may experience hypoesthesia in the injured leg, which contrasts with the finding of hyperesthesia previously observed in other chronic pain conditions but is in accord with patients with nerve injuries and surgeries. This is the first study to examine peripheral sensory nerve function at the site of injury in patients with chronic pain following lower extremity fractures using quantitative sensory testing and current perception threshold testing.
Topics: Adult; Chronic Pain; Cohort Studies; Cross-Sectional Studies; Female; Humans; Lower Extremity; Male; Middle Aged; Pain Measurement; Pain Threshold; Sensory Thresholds
PubMed: 28735556
DOI: 10.1177/1099800417720725