Search results for "Sensory System"
showing 10 items of 1266 documents
Spatial discrimination thresholds for pain and touch in human hairy skin
2001
The traditional concept that pain is poorly localized has been challenged by recent studies, where subjects were able to point to the stimulated spot on the skin with an accuracy of 10-20 mm. Pointing movements themselves, however, have errors of about 15 mm. To determine the limits of sensory performance of the nociceptive system independent of motor performance, point localization of heat pain (540 mJ punctate laser stimuli, 5 mm diameter), mechanical pain (256 mN punctate probe, 200 microm diameter), and touch (16 mN von Frey probe, 1.1 mm diameter) were tested in a two-alternative forced-choice paradigm in 12 healthy subjects. Stimuli were applied in randomized order to two parallel lin…
Clinical evaluation criteria for the assessment of impaired pain sensitivity by thulium-laser evoked potentials
2000
Abstract Objectives : Cortical potentials evoked by carbon dioxide laser pulses have been applied in clinical practice to study nociceptive pathways for several years. In this study, we evaluate the properties of an infrared laser (thulium-YAG) with a penetration depth in the skin that matches the intracutaneous depth of nociceptors. Methods : Temperature measurements and modelling showed that the thulium laser generates painful intracutaneous temperatures with less surface heating than the carbon dioxide laser and with no side effects (up to 600 mJ pulse energy). To develop clinical evaluation criteria, laser-evoked potentials (LEPs) were recorded from 3 midline positions (Fz, Cz, Pz) vers…
Hand-arm vibration syndrome: clinical characteristics, conventional electrophysiology and quantitative sensory testing.
2013
Abstract Objective Workers exposed to vibrating tools may develop hand-arm vibration syndrome (HAVS). We assessed the somatosensory phenotype using quantitative sensory testing (QST) in comparison to electrophysiology to characterize (1) the most sensitive QST parameter for detecting sensory loss, (2) the correlation of QST and electrophysiology, and (3) the frequency of a carpal tunnel syndrome (CTS) in HAVS. Methods QST, cold provocation tests, fine motor skills, and median nerve neurography were used. QST included thermal and mechanical detection and pain thresholds. Results Thirty-two patients were examined (54 ± 11 years, 91% men) at the more affected hand compared to 16 matched contro…
The pattern and time course of somatosensory changes in the human UVB sunburn model reveal the presence of peripheral and central sensitization.
2013
The ultraviolet B (UVB) sunburn model was characterized with a comprehensive battery of quantitative sensory testing (QST). Primary hyperalgesia in UVB-irradiated skin and secondary hyperalgesia in adjacent nonirradiated skin were studied in 22 healthy subjects 24h after irradiation with UVB at 3-fold minimal erythema dose of a skin area 5 cm in diameter at the thigh and compared to mirror-image contralateral control areas. The time course of hyperalgesia over 96 h was studied in a subgroup of 12 subjects. Within the sunburn area, cold hyperesthesia (P=.01), profound generalized hyperalgesia to heat (P.001), cold (P.05), pinprick and pressure (P.001), and mild dynamic mechanical allodynia (…
Effects of transcranial direct current stimulation of the primary sensory cortex on somatosensory perception.
2011
Background: Transcranial direct current stimulation (tDCS) is able to modify cortical excitability and activity in humans. Objective: The aim of the present study was to analyze the effects of tDCS of the primary sensory cortex (SI) on thermal and mechanical perception, assessed by quantitative sensory testing (QST). Methods: The comprehensive QST protocol encompassing thermal and mechanical detection and pain thresholds as devised by the German Research Network on Neuropathic Pain (DFNS) was applied to skin areas innervated by the radial and median nerve of 12 healthy subjects, who were examined before and after each tDCS stimulation type. Anodal, cathodal, and sham tDCS was applied at a 1…
Clinical patterns and electrophysiological findings in retinal pigment epithelium diseases. Does a correlation exist?
1986
At present it is difficult to distinguish those human chorioretinal diseases in which the retinal pigment epithelium (RPE) is the primary site of dysfunction. This difficulty is caused by several factors such as scarcity of biochemical and histological information and a lack of correlation of basic science information available with the clinical body of knowledge. In the present study we examined 134 eyes at early or late stages of hereditary diseases involving the RPE. We tried to distinguish primary RPE involvement by using standard ERG (a- and b-wave) and EOG testing. We conclude that in general primary RPE damage can be better assessed by current electrophysiology in those diseases whic…
PREGO (presentation of Graves' orbitopathy) study: changes in referral patterns to European Group On Graves' Orbitopathy (EUGOGO) centres over the pe…
2015
BACKGROUND/AIMS: The epidemiology of Graves' orbitopathy (GO) may be changing. The aim of the study was to identify trends in presentation of GO to tertiary centres and initial management over time.METHODS: Prospective observational study of European Group On Graves' Orbitopathy (EUGOGO) centres. All new referrals with a diagnosis of GO over a 4-month period in 2012 were included. Clinical and demographic characteristics, referral timelines and initial decisions about management were recorded. The data were compared with a similar EUGOGO survey performed in 2000.RESULTS: The demographic characteristics of 269 patients studied in 2012 were similar to those collected in the year 2000, includi…
Prevalence and causes of blindness and low vision in the Casteldaccia Eye Study.
1994
In a population-based survey performed on the middle-aged and elderly population of Casteldaccia, Sicily, we found that the prevalence of blindness was 0.47% and the prevalence of low vision 1.22%. Unilateral blindness affected 2.81% of the population and unilateral low vision 4.12%. Visual impairment was much more frequently seen in subjects aged 70 years or more than in younger persons. The main cause of visual impairment was cataract, followed by amblyopia, which was responsible for many cases of unilateral low vision.
Persistent antinociception through repeated self-injury in patients with borderline personality disorder.
2012
Abstract Patients with borderline personality disorder, mostly female, exhibit severe autoaggressive behavior, namely an intentionally performed, nonsuicidal self-injury and severe blunting of pain perception, the mechanism of which is hitherto not understood. Because the nociceptive system displays a high degree of plasticity, the aim of this study was to analyze the relationship of pain perception to self-injurious behavior. Pain perception of mechanical and chemical noxious stimuli was studied by quantitative sensory testing in 22 patients (15 female, 7 male) with borderline personality disorder (BPD) according to DSM-IV and 22 age- and gender-matched controls. BPD patients exhibited a s…
Five-year functional outcomes and vault of -20 diopter myopic phakic intraocular lens implantation.
2015
Purpose To evaluate refractive and visual outcomes and complications associated with phakic intraocular lens (pIOL) implantation to correct high myopia. Settings Fernandez-Vega Ophthalmological Institute, Oviedo, Spain. Design Retrospective observational case series. Methods Uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), refraction, vault, and adverse effects were evaluated after 5 years with Visian ICMV4 pIOL. Results Mean spherical equivalent (SE) dropped from −18.32 ± 2.37 diopters (D) preoperatively to −0.88 ± 0.52D 5 years postoperatively; 61% of eyes were within ±0.75 D of the target. The mean Snellen decimal CDVA and UDVA were 0.73 ± 0.23 and 0…