Search results for "thresholds"
showing 10 items of 75 documents
Elektrophysiologische Untersuchung zum Einsatz von Streptolysin O und Natrium-Hyaluronat zur Permeabilitätsmodulation der Membran des runden Fensters…
2003
Background: The round window membrane (RWM) acts like a barrier for topically applied substances into the middle ear preventing diffusion into the perilymphatic fluid compartment. Material and Method: In an animal model, modulation of the permeability of the RWM was attempted using Streptolysin-O (SLO) in various concentrations and sodium hyaluronate. Thereafter, the effect of intratympanically applied Lidocain 2% on hearing threshold measured by auditory brainstem response was tested for Lidocain 2 % and Lidocain 2 % in combination with SLO or sodium hyaluronate. Results: The results show that both, SLO and sodium hyaluronate, influence the effect of Lidocain 2 % on hearing thresholds as a…
Correlates of vibrotactile thresholds in men of different ages
1986
— As a part of a larger gerontological research project vibrotactile thresholds on the inner malleolus of the ankle were studied in 355 men aged 31–35, 51–55 and 71–75 years. The groups studied were random samples of men living in the town of Jyvaskyla in Finland in the year 1981. The thresholds were assessed at three frequencies: 50 Hz, 100 Hz and 250 Hz. The thresholds were associated with age at all frequencies, the means of the threshold values being significantly higher in the older age groups. Within the age groups the thresholds correlated positively with height. In addition, reaction and movement time, leg extension velocity, and postural sway were associated with the thresholds. Ne…
Nasal tactile sensitivity in allergic rhinitis
2011
These preliminary data show a decrease in nasal tactile sensitivity and point out interesting aspects of the nasal chronic inflammatory condition in allergic rhinitis.The aim of this study was to evaluate the effects of allergic rhinitis on nasal tactile sensitivity during the intercritical period.A total of 70 patients aged between 18 and 67 years (average 42 years), with a positive history of allergy caused by seasonal outdoor allergens, were included (group A). Patient outcome was assessed by the nasal monofilament test: a set of 20 Semmes-Weinstein monofilaments was used to detect nasal sensitivity for both nasal cavities. The sensitivity threshold was recorded as the minimum monofilame…
Pulpal ischemia in man: effects on detection threshold, A-delta neural response and sharp dental pain
1999
— Preferential blocks of peripheral nerves have shown that myelinated nerves are more susceptible to local compression and less resistent to asphyxia than unmyelinated fibers. Since two groups of functionally different nociceptors exist in the dental pulp, it is of theoretical and clinical interest to determine the influence of ischemia on the sensitivity of human dental pulp, using standard means for testing tooth vitality and at the same time investigating the intensity coding in one pathway of the afferent trigeminal system. Adrenaline was used to study the differential effect of adrenaline-induced ischemia on intradental A-delta nerve activity (INA) and the concomitant sharp pain, as we…
Characterization of blink reflex interneurons by activation of diffuse noxious inhibitory controls in man.
1998
The blink reflex consists of an early, pontine R1-component and a late, medullary R2-component. R1 and R2 can be evoked by innocuous stimuli, but only the R2 also by painful heat, suggesting that the R2 is mediated by wide dynamic range neurons (WDR) of the spinal trigeminal nucleus. Remote noxious stimuli suppress the activity in WDR neurons via activation of diffuse noxious inhibitory controls (DNIC), whereas low-threshold mechanoreceptive neurons (LTM) are unaffected. In order to characterize the trigeminal interneurons of R1 and R2 we investigated the modulation of the blink reflex by remote painful heat. The blink reflex was elicited in 11 healthy subjects by innocuous electrical pulse…
Color and lightness constancy in different perceptual tasks
1998
Color and lightness constancy with respect to changing illumination was studied with three different perceptual tasks: ranking of colored papers according (1) to their lightness and (2) to their chromatic similarity in photopic, mesopic, and scotopic states of adaptation, and (3) recognition of remembered colored papers after changes of illumination in photopic vision. Constancy was found in the second task, only. Excitations of light receptors and luminance channels were computed to simulate the empirical rank orders. Results of the first task can be predicted with the hypothesis that luminance channels are activated, if lightness is asked for. Sequences arranged with respect to chromatic …
Lateralized and Bilateral Olfactory Function in Patients With Chronic Sinusitis Compared With Healthy Control Subjects
1998
Results of this study demonstrated that a new olfactory test, the "Sniffin' Sticks," can be used to distinguish hyposmic patients with chronic sinusitis (n = 63) from control subjects. Dirhinic testing yielded improved olfactory sensitivity compared with monorhinic testing. However, dirhinic results were not significantly different from results obtained for the best nostril.
Image quality and visual performance in the peripheral visual field following photorefractive keratectomy.
2002
ABSTRACT PURPOSE: A theoretical and experimental study was performed to assess the possible effects of photorefractive keratectomy (PRK) on retinal image quality and thresholds in the peripheral visual field. METHODS: Simple optical calculations suggest that although the quality of the retinal image at the fovea of the postoperative PRK eye may be comparable to that in an emmetropic eye, images in the peripheral field may be markedly worse, since peripheral ray bundles may pass partly through ablated and partly through unablated cornea, giving a simultaneous-vision bifocal effect. This would be expected to create an annular zone of confusion, so that light from two different directions in o…
Basal opioid receptor binding is associated with differences in sensory perception in healthy human subjects: a [18F]diprenorphine PET study.
2009
The endogenous opioid system is involved in many body functions including pain processing and analgesia. To determine the role of basal opioid receptor availability in the brain in pain perception, twenty-three healthy subjects underwent positron emission tomography (PET) utilizing the subtype-nonselective opioid antagonist [(18)F]diprenorphine, quantitative sensory testing (QST) and the cold pressor test. Binding potentials (BPs) were calculated using a non-invasive reference tissue model and statistical parametric mapping was applied for t-statistical analysis on a voxelwise basis. We found that cold pain-sensitive subjects present a significantly lower BP in regions including the bilater…
Olfactory Dysfunction After Head Injury
2008
Objective: To determine the incidence of olfactory dysfunction after head trauma using clinical and radiologic findings, quantitative assessment, and electro-physiologic methods. Participants: A total of 190 patients with head trauma of different severity (n = 32 with mild traumatic brain injury (TBI), n = 94 with signs of moderate TBI, and n = 64 with severe TBI) 6 to 32 months prior to the study. Design: Patients were selected retrospectively, surveyed by telephone (n = 190), and screened for olfactory function with Brief Smell Identification Test (n = 82). Those with olfactory dysfunction were assessed as outpatients using the Sniffin' Sticks (n = 19) and olfactory-evoked potential recor…