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Perception Threshold (perception + threshold)
Kinds of Perception Threshold Selected AbstractsTolterodine causes measurable restoration of urethral sensation in women with urge urinary incontinence,,NEUROUROLOGY AND URODYNAMICS, Issue 4 2010Kimberly Kenton Abstract Introduction & Hypothesis Determine if treatment of urge incontinence with tolterodine results in changes in bladder and/or urethral sensation using Current Perception Threshold (CPT) testing. Methods Women with ,1 incontinence episode on 7-day diary were treated with 4 mg of long-acting tolterodine for 2-months. At baseline and 2-months, participants had CPT testing of the urethral and bladder at 3 frequencies 2000, 250, and 5 Hz. Baseline and post-treatment measures were compared using Wilcoxon Signed Rank Test. Results Seventeen women underwent baseline CPT testing. Four discontinued medication due to side effects and did not have repeated testing. Urethral CPT at 250 Hz was lower after treatment (median 1.3 [Interquartile range .69--2.1] and .75 [.45--1.2], p,=,.003) and at 5 Hz trended toward a significant decrease (1.1 [1--1.9] and .84 [.32--1.1], p,=,.06). Conclusions Urethral sensitivity improves after 2-months of tolterodine, suggesting it may restore urethral sensory nerves in addition to known motor effects. Neurourol. Urodynam. 29:555,557, 2010. © 2009 Wiley-Liss, Inc. [source] The value of the Rydel-Seiffer tuning fork as a predictor of diabetic polyneuropathy compared with a neurothesiometerDIABETIC MEDICINE, Issue 6 2004T. Kästenbauer Abstract Aims The aim of the study was to investigate the predictive value of the Rydel-Seiffer tuning fork for detecting diabetic neuropathy and to compare it with an electronic neurothesiometer. Methods In 2022 consecutive diabetic subjects, peripheral polyneuropathy was diagnosed by vibration perception threshold (VPT) at the tip of both great toes using a 128-Hz tuning fork and a neurothesiometer, by simple bedside tests and by the presence of neuropathic symptoms. These evaluations were further combined to diagnose peripheral nerve dysfunction (abnormal bedside tests) and symptomatic neuropathy. VPT was also measured in 175 non-diabetic control subjects to define normal values. Results VPT was normal in 1917 subjects and abnormal in 105 (5.2%) patients when measured by the tuning fork. Patients with an abnormal vibration test were significantly (P < 0.0001) older than subjects with a normal vibration sense, while diabetes duration and HbA1c of the former were also significantly elevated. The same was true for the percentages of an abnormal 10-g monofilament test (66.7% vs. 7.2%, P < 0.0001) and a missing Achilles' tendon reflex (68.6% vs. 24.8%, P < 0.0001). Finally, the VPT measured by the neurothesiometer was 2.5 times higher in patients with an abnormal tuning fork test (32.0 ± 9.8 vs. 12.5 ± 6.4 V, P < 0.0001). The plot of the difference of both methods against their mean yielded a good agreement of the two VPT measurements, and the tuning fork had a high sensitivity and positive predictive value for the diagnosis of abnormal bedside tests and for symptomatic neuropathy. Conclusion The tuning fork reliably detected peripheral neuropathy in comparison with the neurothesiometer. A tuning fork is a useful screening test for diabetic neuropathy. [source] Intraepidermal nerve fibre density, quantitative sensory testing and nerve conduction studies in a patient material with symptoms and signs of sensory polyneuropathyEUROPEAN JOURNAL OF NEUROLOGY, Issue 2 2006S. Løseth Small diameter nerve fibre (SDNF) neuropathy is an axonal sensory neuropathy affecting unmyelinated (C) and thin myelinated (A-delta) fibres. We have evaluated 75 patients with symptoms and signs suggesting SDNF dysfunction with or without symptoms and signs of co-existing large diameter nerve fibre involvement. The patients were examined clinically and underwent skin biopsy, quantitative sensory testing (QST) and nerve conduction studies (NCS). The purpose of this study was to compare the relationship between the different methods and in particular measurements of thermal thresholds and intraepidermal nerve fibre (IENF) density in the same site of the distal leg. The main subdivision of the patient material was made according to the overall NCS pattern. Patients with normal NCS (38) had 6.4 ± 3.8 and patients with abnormal NCS (37) had 4.4 ± 3.4 IENF per mm (P = 0.02). Limen (difference between warm and cold perception thresholds) was significantly higher (more abnormal) in those with abnormal than in those with normal NCS (22.1 ± 9.1 vs. 13.4 ± 5.6, P < 0.0001). Cold perception threshold was more abnormal (P < 0.0001) than warm perception threshold (P = 0.002). Correlation between IENF and QST was statistically significant only when NCS was abnormal, and thus dependent of a more severe neuropathic process in SDNFs. [source] Lower limb nerve impairment in diabetic patients: multiperspective assessmentEUROPEAN JOURNAL OF NEUROLOGY, Issue 1 2002L. Padua To assess the relationship between patient's perception of his own inferior limbs symptom and function and the clinical-neurophysiological assessment in patients affected by insulin-dependent diabetes mellitus (IDDM). We studied 50 consecutive outpatients affected by IDDM (23 men, 27 women). We used validated measurements clinical [Semmes,Weinstein (SW), vibration perception threshold (VPT), muscle strength, osteotendineous reflexes, etc.], neurophysiological (sural, peroneal nerves), metabolic and patient-oriented [North American Spine Society (NASS) questionnaire]. Patient-oriented scores were significantly related with neurophysiological findings of the inferior limbs. Our data suggest that electrodiagnostic tests are useful to assess the severity of the diabetic polyneuropathy not only because they provide a biological measurement of the nerve function but also because they appeared related to the patient's quality of life related to the peripheral nerve involvement. [source] Stimulation threshold comparison of time-varying magnetic pulses with different waveformsJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 1 2009Werner Irnich PhD Abstract Purpose To clarify whether sinusoidal pulses possess lower thresholds than rectangular ones at perception threshold, a statement often made that contradicts the theory of stimulation. Materials and Methods The results of a nerve stimulation study with 65 volunteers and with trapezoidal and sinusoidal gradient pulses were used to apply the combination of the electric field, induced in the tissue of the human body, with the "Fundamental Law of Electrostimulation." This law claims that the waveshape of a pulse is not essential as long as the amplitude of the pulse does not decrease below rheobase (rheobase condition). Results If the rheobase condition is applied to sinusoidal waveforms and the pulse duration and amplitude is corrected accordingly, both trapezoidal and sinusoidal gradient pulses have identical threshold amplitudes as a function of pulse duration. Conclusion The "Fundamental Law of Electrostimulation," including the "rheobase condition," proved to be a good basis for describing magnetic field stimulation (magnetostimulation) and that application of it to magnetostimulation is suitable as the basis for describing magnetic field stimulation with various waveforms. For nonrectangular pulses, pulse durations and pulse amplitudes must be corrected according to the "rheobase condition." The exponential Blair Equation is less suited to be applied in magnetostimulation. J. Magn. Reson. Imaging 2009;29:229,236. © 2008 Wiley-Liss, Inc. [source] Influence of topical capsaicin on facial sensitivity in response to experimental painJOURNAL OF ORAL REHABILITATION, Issue 1 2007Y.-S. LEE summary, Capsaicin, the pungent component of the red pepper, has been used as an analgesic in a variety of pain conditions, but sensory impairment after long-term treatment has been concerned. This study investigated the influence of topical capsaicin on various types of sensations including pain in the facial areas innervated by the mental nerve, and also evaluated whether the measurement of cutaneous current perception threshold (CPT) is reliable for the quantification of sensory change following capsaicin application. Twenty healthy subjects were given topical capsaicin cream (0·075%), which was applied to the mental area unilaterally, four times daily for 2 weeks. Burning sensation after capsaicin application gradually decreased with repeated applications. Repeated topical capsaicin resulted in reduced sensation to mechanical, heat and cold pain without changing non-painful tactile sensation. It also resulted in increased CPTs at 5 Hz and 250 Hz stimuli but no change in the CPTs at 2000 Hz from the first evaluation after capsaicin treatment and throughout the treatment period. This study demonstrated that topical capsaicin treatment for the management of chronic localized pain can be safely applied to the face without affecting non-painful normal sensations, and that CPT testing is a clinically useful tool for the quantification of sensory changes following capsaicin application. [source] Comparison of oral sensory function in complete denture and implant-supported prosthesis wearersJOURNAL OF ORAL REHABILITATION, Issue 3 2001Kyung-Soo Jang In order to compare the differences of part of the oral sensory functions among natural dentition, complete denture wearers and implant-supported prostheses wearers, tactile and pressure awareness was measured. Tactile sense was estimated by the thickness perception threshold between upper and lower dentition. Sensibility of pressure feeling was evaluated by threshold of lateral loading on tooth. Within this limited experiment, it could be concluded that an osseointegrated root form implant helped towards restoration of oral sensory functions. [source] Human Perception of Dental Porcelain Translucency Correlated to Spectrophotometric MeasurementsJOURNAL OF PROSTHODONTICS, Issue 3 2010Min-Chieh Liu DDS Abstract Purpose: This study evaluated the relationship between instrumental measurements and subjective visual assessment of differences in dental porcelain translucency. Materials and Methods: Unshaded feldspathic porcelain was used with controlled amounts of tin oxide to create two groups of 12-mm diameter disks with incremental changes in opacity. Contrast ratio (CR = Yb/Yw) was determined with a spectrophotometer, and used as a measure of porcelain translucency (Group A = 0.20 to 0.40; Group B = 0.6,0.8). Within each group, there were 14 specimens with 11 CRs. Three observer groups (first year dental students, residents, faculty with >10 years of shade matching experience) were recruited to assess the translucency between porcelain disks under two lighting conditions (reflected light, transmitted light). Each subject's ability to distinguish between specimens of differing translucency was determined. Descriptive statistics and three-way ANOVA followed by a post-hoc Tukey-Kramer test were used to evaluate the translucency perception threshold (TPT) of subjects (,= 0.05). Results: The overall mean TPT (,C) was 0.07, while 50% of the subjects could perceive a 0.06 CR difference between porcelain specimens. Three-way ANOVA revealed a significant difference in translucency perception among the observer groups (p < 0.0001), whereas the main effects for porcelain opacity (p= 0.3038) and lighting condition (p= 0.0645) were not significant, and no significant interactions were found. Post-hoc Tukey-Kramer test indicated that the mean TPT observed in the faculty group (,C = 0.04) was significantly lower than those observed in student (,C = 0.09) and resident groups (,C = 0.08), while there was no significant difference between students and residents. Conclusions: The overall mean TPT of all subjects was 0.07, and 50% of the study population perceived a 0.06 CR difference in translucency. Increased shade matching experience (,10 years) significantly improved the ability to perceive differences in translucency; however, neither the viewing condition nor porcelain opacity affected the perceived translucency threshold. [source] Electrosensibility and electromagnetic hypersensitivityBIOELECTROMAGNETICS, Issue 6 2003Norbert Leitgeb Abstract Electromagnetic sensibility, the ability to perceive electric and electromagnetic exposure, and electromagnetic hypersensitivity (EHS), developing health symptoms due to exposure to environmental electromagnetic fields, need to be distinguished. Increased electrosensibility is a necessary, however, not a sufficient condition for electromagnetic hypersensitivity. At an extended sample of the general population of 708 adults, including 349 men and 359 women aged between 17 and 60 years, electrosensibility was investigated and characterized by perception threshold and its standard deviation. By analyzing the probability distributions of the perception threshold of electric 50 Hz currents, evidence could be found for the existence of a subgroup of people with significantly increased electrosensibility (hypersensibility) who as a group could be differentiated from the general population. The presented data show that the variation of the electrosensibility among the general population is significantly larger than has yet been estimated by nonionizing radiation protection bodies, but much smaller than claimed by hypersensitivity self-aid groups. These quantitative results should contribute to a less emotional discussion of this problem. The investigation method presented, is capable of exclusion diagnostics for persons suffering from the hypersensitivity syndrome. Bioelectromagnetics 24:387,394, 2003. © 2003 Wiley-Liss, Inc. [source] Comparison of skin barrier function and sensory nerve electric current perception threshold between IgE-high extrinsic and IgE-normal intrinsic types of atopic dermatitisBRITISH JOURNAL OF DERMATOLOGY, Issue 1 2010T. Mori Summary Background, Two types of atopic dermatitis (AD) have been proposed, with different pathophysiological mechanisms underlying this seemingly heterogeneous disorder. The extrinsic type shows high IgE levels presumably as a consequence of skin barrier damage and feasible allergen permeation, whereas the intrinsic type exhibits normal IgE levels and is not mediated by allergen-specific IgE. Objectives, To investigate the relationship between pruritus perception threshold and skin barrier function of patients with AD in a comparison between the extrinsic and intrinsic types. Methods, Enrolled in this study were 32 patients with extrinsic AD, 17 with intrinsic AD and 24 healthy individuals. The barrier function of the stratum corneum was assessed by skin surface hydration and transepidermal water loss (TEWL), and pruritus perception was evaluated by the electric current perception threshold (CPT) of sensory nerves upon neuroselective transcutaneous electric stimulation. Results, Skin surface hydration was significantly lower and TEWL was significantly higher in extrinsic AD than intrinsic AD or normal controls. Although there was no statistically significant difference in CPT among extrinsic AD, intrinsic AD and normal controls, CPT was significantly correlated with skin surface hydration and inversely with TEWL in intrinsic AD and normal controls, but not extrinsic AD. Finally, CPT was correlated with the visual analogue scale of itch in the nonlesional skin of patients with extrinsic but not intrinsic AD. Conclusions, Patients with extrinsic AD have an impaired barrier, which increases the pre-existing pruritus but rather decreases sensitivity to external stimuli. In contrast, patients with intrinsic AD retain a normal barrier function and sensory reactivity to external pruritic stimuli. [source] Intraepidermal nerve fibre density, quantitative sensory testing and nerve conduction studies in a patient material with symptoms and signs of sensory polyneuropathyEUROPEAN JOURNAL OF NEUROLOGY, Issue 2 2006S. Løseth Small diameter nerve fibre (SDNF) neuropathy is an axonal sensory neuropathy affecting unmyelinated (C) and thin myelinated (A-delta) fibres. We have evaluated 75 patients with symptoms and signs suggesting SDNF dysfunction with or without symptoms and signs of co-existing large diameter nerve fibre involvement. The patients were examined clinically and underwent skin biopsy, quantitative sensory testing (QST) and nerve conduction studies (NCS). The purpose of this study was to compare the relationship between the different methods and in particular measurements of thermal thresholds and intraepidermal nerve fibre (IENF) density in the same site of the distal leg. The main subdivision of the patient material was made according to the overall NCS pattern. Patients with normal NCS (38) had 6.4 ± 3.8 and patients with abnormal NCS (37) had 4.4 ± 3.4 IENF per mm (P = 0.02). Limen (difference between warm and cold perception thresholds) was significantly higher (more abnormal) in those with abnormal than in those with normal NCS (22.1 ± 9.1 vs. 13.4 ± 5.6, P < 0.0001). Cold perception threshold was more abnormal (P < 0.0001) than warm perception threshold (P = 0.002). Correlation between IENF and QST was statistically significant only when NCS was abnormal, and thus dependent of a more severe neuropathic process in SDNFs. [source] Study on functional constipation and constipation-predominant irritable bowel syndrome by using the colonic transit test and anorectal manometryJOURNAL OF DIGESTIVE DISEASES, Issue 4 2002Li Xing ZHAN OBJECTIVE: To investigate the visceral perception, anorectal pressure and colonic transit time (CTT) in patients with functional constipation and constipation-predominant irritable bowel syndrome (C-IBS), and to study the manometric abnormalities of these two conditions. METHODS: The CTT in patients with functional constipation and C-IBS was studied by using radiopaque markers. Rectal visceral perception thresholds, rectal compliance and anorectal pressure were examined by electric barostat. RESULTS: The CTT in both groups of constipated patients was abnormal. A lot of radiopaque markers remained in the right colon in C-IBS patients, whereas in patients with functional constipation, the radiopaque markers remained in each segment of the colon. The anorectal resting pressure, squeezing pressure and relaxation pressure were normal in both groups. Rectal compliance and defecation thresholds were much higher compared with controls, and the rectal visceral perception of functional constipation was also abnormal. CONCLUSIONS: The motility abnormalities of functional constipation and C-IBS occurred in different colonic segments. Results suggest that CTT measurement and anorectal manometry could be helpful in the differential diagnosis of these two conditions. [source] Visceral perception thresholds after rectal thermal and pressure stimuli in irritable bowel syndrome patientsJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 2 2004YANQING LI Abstract Background and Aim:, Visceral hypersensitivity has been shown to be present in irritable bowel syndrome (IBS). The current study sought to compare the characteristics of visceral perception thresholds after rectal thermal and pressure stimuli between IBS patients and healthy subjects. Methods:, A total of 46 patients with IBS were diagnosed using Rome II criteria. Thirteen healthy individuals participated in the study. Rectal visceral perception thresholds were examined in patients with IBS and in normal controls after thermal and pressure stimuli. Subjects were asked to report the sensation type, location, and spread. Results:, Compared with healthy subjects, IBS patients demonstrated significantly initially lower perception thresholds and defecation thresholds to rectal thermal and pressure stimuli, particularly in patients with diarrhea-predominant IBS. Ice stimuli on the abdominal wall had varied effects on symptoms in patients with IBS and did not affect perception thresholds. Conclusions:, Visceral perception thresholds were decreased significantly after rectal thermal and pressure stimuli in patients with IBS. Visceral hypersensitivity may be one of the important pathogenic mechanisms in IBS. [source] Quantitative Sensory Testing in Patients With Chronic Unilateral Radicular Neuropathic Pain and Active Spinal Cord StimulationNEUROMODULATION, Issue 3 2006Dirk Rasche MD Abstract Objectives., Spinal cord stimulation (SCS) is an effective treatment option for chronic radicular neuropathic pain syndromes. This prospective study was performed to examine the peripheral effects of SCS on sensation using quantitative sensory testing (QST). Materials and Methods., We measured two consecutive QST measurements for thermal, tactile-static, tactile-dynamic, vibratory, and pain sensation of the lower limbs in seven patients with chronic unilateral radicular neuropathic pain who underwent SCS implantation for their pain. Measurements were performed when SCS was turned off and once again during SCS and subsequent reduced pain levels. Results., Baseline QST demonstrated significantly increased thresholds for tactile and warm and cold detection in the pain area. With SCS active, a significant reduction of the cold and warm perception and mechanical detection thresholds was found on the painful side (p < 0.01). Although not significant (p > 0.01), altered sensory thresholds with active SCS also were found at the healthy side where no paresthesias were felt. Conclusion., SCS leads to bilateral subclinical effects even if the evoked paresthesias are only unilateral. Pain perception thresholds are not altered with therapeutic SCS. [source] Comparison of conventional and non-invasive techniques for the early identification of diabetic neuropathy in children and adolescents with type 1 diabetesPEDIATRIC DIABETES, Issue 6 2006Danielle Nelson Background:, Neuropathy is an important complication and contributes to the morbidity of diabetes mellitus. The availability of simple and non-invasive tests for screening of early diabetic neuropathy (DN) in children with diabetes may prevent further progression of this complication. The purpose of this study was to compare conventional nerve conduction studies (NCS) with non-invasive techniques, including vibration perception thresholds (VPT) and tactile perception thresholds (TPT) for the detection of DN in children and adolescents with type 1 diabetes. Methods:, Children from the Alberta Children's Hospital Diabetes Clinic with at least 5 yr duration of type 1 diabetes underwent detailed evaluations, including neurologic exam, NCS, VPT, and TPT testing. Information on duration of diabetes, height, and mean glycosylated hemoglobin (A1C) were also collected. Descriptive statistics, including Student's t -test and chi-squared test, were used for analysis. Results:, Seventy-three children (mean age of 13.7 ± 2.6 yr) completed the study. The mean duration of diabetes was 8.1 ± 2.6 yr, and the mean A1C was 9.0 ± 1.0%. Forty-two (57%) children had DN based on NCS. Using NCS as a gold standard, the sensitivity and specificity of VPT were 62 and 65%, while the sensitivity and specificity of TPT were 19 and 64%, respectively. Conclusions:, Subclinical DN is common among children and adolescents with type 1 diabetes, and there is a need for better metabolic control in this population. VPT and TPT may not be adequate screening tools for the detection of DN in children. [source] Sural nerve biopsy may predict future nerve dysfunctionACTA NEUROLOGICA SCANDINAVICA, Issue 1 2009S. Thrainsdottir Objective,,, Sural nerve pathology in peripheral neuropathy shows correlation with clinical findings and neurophysiological tests. The aim was to investigate progression of nerve dysfunction over time in relation to a baseline nerve biopsy. Methods,,, Baseline myelinated nerve fiber density (MNFD) was assessed in sural nerve biopsies from 10 men with type 2 diabetes, 10 with impaired and 10 with normal glucose tolerance. Nerve conduction and quantitative perception thresholds were estimated at baseline and follow-up (7,10 years later). Results,,, Subjects with low MNFD (,,4700 fibers/mm2) showed decline of peroneal amplitude (P < 0.02) and conduction velocity (P < 0.04), as well as median nerve sensory amplitude (P < 0.05) and motor conduction velocity (P < 0.04) from baseline to follow-up. In linear regression analyses, diabetes influenced decline of nerve conduction. MNFD correlated negatively with body mass index (r = ,0.469; P < 0.02). Conclusion,,, Low MNFD may predict progression of neurophysiological dysfunction and links obesity to myelinated nerve fiber loss. [source] | ||||||||||||||||||||||