The limit of tactile spatial resolution in humans: grating orientation discrimination at the lip, tongue, and finger

The sensory neural pathways serving the lip, tongue, and finger are specialized for spatial information processing; thus, damage to these pathways is likely to be manifested most prominently as a loss of spatial acuity. For that reason, accurate measurement of spatial resolution at these regions is particularly important. The conventional test, the two-point discrimination task, does not measure the limit of spatial resolution and it yields variable results because it does not control nonspatial cues. The aim of this study was to quantify the limits of spatial resolution at the lip, tongue, and finger and to study the repeatability of those measurements using a stimulus that does not introduce nonspatial cues. We employed a grating orientation discrimination test, which has been studied extensively in relation to the underlying neural mechanisms. We obtained psychophysical thresholds for tactile spatial resolution from 15 normal, young adult subjects over seven test sessions. The finest gratings whose orientations were discriminated reliably had groove widths (gratings had equal groove and bar widths) that averaged 0.51 mm at the lip, 0.58 mm at the tongue, and 0.94 mm at the finger. These threshold measurements were highly reproducible between sessions with an overall improvement of 2% per session. These data suggest that the grating orientation discrimination task provides a stable, reliable measure of the human capacity for spatial resolution.     

Decision making in detecting abnormal Semmes-Weinstein monofilament thresholds in carpal tunnel syndrome

Both hands of 39 patients who had symptoms of pain and/or numbness in one or both hands were tested by two hand therapists using the full kit of Semmes-Weinstein monofilaments (SWMFs). The SWMF thresholds were obtained for the thumb, the index finger, and the long and small fingers. These thresholds were classified as normal or abnormal based on four decision rules and two criterion measures. Decision rules were based on whether SWMF 2.83 or 3.22 would be the best limit of normality, and whether the small finger should be used for within-subject comparisons. The criterion measures were the highest threshold of all three radial digits and the highest threshold of the long finger alone. Intertherapist agreement on normality was fair to moderate (kappa = 0.22-0.51), varying according to decision rules and criterion measures. Reliability was higher when the additional comparison with the small finger was omitted. High accuracy in identifying cases of carpal tunnel syndrome (CTS) was possible, but accuracy varied moderately between testers and greatly according to decision rules and criterion measurements. The best overall accuracy (81%-82% sensitivity and 57%-86% specificity) was achieved when SWMF 2.83 was used as the upper limit of normality and the small finger was used for within-subject comparison, and when data from the long finger alone were used for decision making.     

The influence of age on the assessment of motor unit activation in a human hand muscle

Two indices of motor unit recruitment, the ramp-force and repetitive-discharge thresholds, were compared in the first dorsal interosseus muscle of ten young and twelve elderly subjects. The purpose was to determine the effect of age on the relationship between the two recruitment thresholds and the spike-triggered average force of motor units. Each subject performed three tasks requiring isometric abduction of the left index finger: a maximum voluntary contraction (MVC), a ramp-and-hold contraction, and a repetitive-discharge task. The elderly subjects used coactivation of the antagonist muscle (second palmar interosseus) more frequently than the young subjects during the ramp-and-hold contraction. Many elderly subjects expressed difficulty with the controlled ramp-down phase of the ramp-and-hold contraction and preferred a coactivation strategy to a derecruitment strategy for this task. There were no differences due to age or gender in the ramp-force thresholds between the various groups. However, the normalized repetitive-discharge threshold was significantly less for the younger subjects and for the male subjects. Nonetheless, the two recruitment thresholds were able to predict the spike-triggered average force with similar success for both the young and the elderly subjects. These data suggest that the recruitment threshold of a motor unit in first dorsal interosseus was characterized equally well by either the ramp-force or repetitive-discharge measurement for both young and elderly subjects but that coactivation was used more frequently by the elderly subjects during the ramp-and-hold task.     

Functional intracellular P-glycoprotein

PURPOSE: To report a novel binocular perimetry test to identify monocular functional vision loss. METHODS: In a prospective study, 10 patients with monocular functional vision loss, 10 patients with monocular organic vision loss, and 10 normal subjects were tested using a Humphrey automated perimeter attachment that performs central threshold perimetry of both eyes in a single test. First, patients were tested after being told their "good" (unaffected) eye was being tested; this was followed by a second identical test said to be on the "bad" (affected) eye. Two measurements were calculated for each subject: the functional component (deltaF), defined as the difference (in dB) between the mean threshold of the first and second tests, and the organic component (deltaO), the difference (in dB) between the mean threshold of the unaffected and affected eyes. RESULTS: Patients with monocular functional vision loss produced lower thresholds when they thought their affected eye alone was being tested but little intereye difference (mean deltaF +/- SD = 17.35 +/- 7.50 dB; mean deltaO = 0.01 +/- 1.40 dB). Patients with monocular organic vision loss had little difference between tests and lower thresholds in their affected eye (mean deltaF = 0.84 +/- 1.15 dB; mean deltaO = 9.01 +/- 4.71 dB). Normal subjects demonstrated little intertest or intereye differences (mean deltaF = -0.15 +/- 0.78 dB; mean deltaO = -0.05 +/- 0.51 dB). CONCLUSION: This perimetry method effectively distinguished between normal subjects, patients with monocular functional vision loss, and patients with monocular organic vision loss.     

A relationship between proteinase activity and clinical parameters in the treatment of periodontal disease

The objective of this research was to determine the effectiveness of a biochemical assay which measures proteolytic enzyme activity in gingival crevicular fluid (GCF) and to relate this enzyme activity to clinical parameters traditionally utilized for periodontitis detection. A clinical trial was conducted on 8 periodontitis subjects with > or =4 sites exhibiting a loss of attachment of > or =5 mm and probing depths of > or =5 mm with bleeding on probing. On each subject, a plaque index was performed, followed by GCF sampling at those sites which exhibited a loss of attachment and probing depths. GCF was analyzed for activity against benzoyl-L-arginine-p-nitroanilide in the presence (BAPNA w/gly-gly) and the absence (BAPNA w/o gly-gly) of glycyl-glycine and against MeOSuc-Ala-Ala-Pro-Val-pNA and Suc-Ala-Ala-Pro-Phe-pNA for neutrophil serine proteinases activity (elastase and cathepsin G, respectively). Subsequently, a gingival index was performed, attachment levels and probing depths were recorded using a constant force probe with bleeding on probing being noted. A split-mouth design was employed and half mouths were randomly assigned to the following treatment groups: group A, half of the mouth received scaling/root planing and polishing: group B, half of the mouth received no treatment (control). Subjects were treated, then instructed on toothbrushing and interdental cleaning. After 4 weeks, subjects returned to receive a plaque index; GCF sampling, gingival index, attachment levels, probing depths and bleeding on probing as described above. Using a paired Student t-test, the findings suggest that BAPNA w/gly-gly was significantly less in treatment sites than in non-treated control sites (p=0.05). No such correlation was found for other activities, including neutrophil serine proteinases which were shown to occur in GCF in free, proteolytically active forms. In addition, significant treatment effects were detected for probing depths (p= 0.03) which reduced by 1.3 mm and attachment levels (p=0.02) which gained 0.7 mm. The reduction of P. gingivalis from treated periodontitis sites as detected by a significant decrease in BAPNA w/ gly-gly may prove to be a valuable marker for periodontal disease activity.     

Functional psychomotor deficits associated with carpal tunnel syndrome

A reliable task was developed for investigating functional deficits associated with carpal tunnel syndrome (CTS). A rapid pinch and release psychomotor task utilizing muscles of the hand innervated by the median nerve was administered using a strain gauge dynamometer and providing limited force feedback. The motor performance characteristics studied were speed and force control. An experiment was conducted for studying the effects of force level, hand dominance, test-retest reliability, learning, and inter-subject variability using 13 subjects free from any hand disabilities or symptoms. A companion study was also conducted using 17 normal subjects and ten subjects diagnosed having CTS to investigate differences between CTS and control subjects. Dominant hands performed 4% to 8% better than the non-dominant hands by having a greater pinch rate, a smaller overshoot force, and less time above the upper force level and below the lower force level. Control subjects performed 25% to 82% better than CTS subjects. Age contributed 6% of the total variance for pinch rate and 7% of the total variance for the time below the lower force level. The results suggest that people suffering from CTS may experience similar functional psychomotor deficits in daily living and manual work activities.     

Decreased pain threshold and tolerance in patients with chronic tension headache

Nociceptive processing was studied in 40 patients with chronic tension-type headache and in 40 healthy controls. We found that pericranial tenderness recorded by manual palpation was considerably higher in patients than in controls (p < or = 0.0002). Pressure pain detection and tolerance thresholds recorded in the finger, by means of a pressure algometer, were significantly lower in patients than in controls (p < or = 0.0009), and a non-significant similar trend was observed in the temple (p < or = 0.12). Detection and tolerance thresholds were decreased to a similar degree in patients compared with controls, and pain thresholds recorded in the finger and in the temple were highly correlated (r = 0.84, p < 0.0001). The electrical pain threshold at the labial commissure, by means of an electrical stimulator, was significantly decreased in patients compared with controls (p = 0.03). All of the examined pain thresholds were significantly correlated to the pericranial tenderness recorded by palpation (r = -0.35 to -0.53, p < or = 0.03). We conclude that the present finding of a general hypersensitivity to pain stimuli in chronic tension-type headache indicates that central factors play an important role in the pathogenesis of this disorder.     

Mutation analysis of S182 (presenilin-I) in patients with familial Alzheimer''s disease and its biological function

OBJECTIVE: We studied the long-latency response of the orbicularis oris muscle elicited with transcranial magnetic stimulation in patients with hemifacial spasm (HFS) and evaluated the excitability of the facial nucleus. METHODS: We compared the thresholds on both sides in 8 normal volunteers and 7 patients with hemifacial spasm. The thresholds were determined as the lowest intensity required to produce motor evoked potentials with an amplitude of at least 50 microV in the orbicularis oris muscle. Average values were given as means +/- standard deviation. Wilcoxon's rank sum test was used for comparisons between the sides of normal subjects and of patients with HFS with respect to the threshold stimulus. RESULTS: There was no significant difference between the thresholds on the two sides of the normal subjects (mean 1.88+/-5.30%, P > 0.05). In patients with HFS, there was a significant difference between the thresholds on the spasm side and the normal side (mean 20.7+/-13.0%, P < 0.05) In one patient studied after MVD, the difference between both sides disappeared. CONCLUSION: The difference between the thresholds in patients with HFS and the normalization in threshold after MVD suggested that the mechanism of HFS was hyperexcitability of the facial nucleus.     

The rate of periodontal attachment loss in subjects with established periodontitis

A stepwise approach to determine attachment level changes was utilized to assess the nature of progression of periodontal disease. Following initial screening, 51 subjects with established periodontitis were monitored quarterly for 9 more months. Probing depth (PD) and relative attachment level (RAL) were recorded using an automated, pressure sensitive probe system. To establish intra-examiner error, repeated measurements were performed for all sites at the final visit. An overall standard deviation (SD) for RAL repeated measurements was initially calculated (0.76 mm) using all 6,935 double measurements. Sites were sorted by factors which contribute to the error of attachment level measurements; i.e., pocket depth (shallow, moderate, deep), tooth type (molar, non-molar) and location (buccal, lingual). Data were sorted by the above 12 groups, and SD for repeated measurements was calculated separately for them. The ratio between these SD and the overall SD served as the corrective factor. Each patient's initial threshold (2 SD) was multiplied by these corrective factors thus resulting in 12 thresholds for each subject. Next, linear, exponential and logarithmic regression models were tested for each site, and the regression model showing the highest R value was chosen for that site. AL changes were tested against the patient's threshold for that site. Sites with attachment loss exceeding the threshold were deemed active. Five hundred eighty-one sites (8.3%) exhibited attachment loss exceeding the various thresholds. Of these, linear progression occurred in 195, logarithmic in 224, and exponential in 162 sites. Individual patient's attachment loss ranged from 0.6 to 19.4% of all sites.(ABSTRACT TRUNCATED AT 250 WORDS)     

Punctate pressure sensitivity: effects of skin temperature

The dependence on skin temperature of tactile sensitivity to punctiform (hair) stimulation of the finger tip came under study in five subjects. Their data show that punctate sensitivity is relatively stable over a wide range of thermal environments. On the average, some elevation of touch threshold occurred at a skin temperature of 20 degrees C (i.e., about 10 degree below normal), but severe loss of sensitivity first occurred at 10 degrees C. A small but possibly insignificant loss appeared at skin temperatures of 40 and 43 degrees C. The relatively stable behavior of the punctate threshold between about 20 and 40 degrees C contrasts with that of the vibrotactile threshold, which, at least for high frequencies, depends strongly on the skin temperature.     

Quantitative changes in periplasmic proteins of the macronucleus-specific bacterium Holospora obtusa in the infection process of the ciliate Paramecium caudatum

PURPOSE: This study was conducted to test the hypothesis that clonidine produces a dose-dependent increase in the sweating threshold and dose-dependent decreases in vasoconstriction and shivering thresholds. METHODS: Six healthy subjects (two female) were studied on four days after taking clonidine in oral doses of either 0 (control), 3, 6 or 9 micrograms.kg-1. The order followed a balanced design in a double-blind fashion. Oesophageal temperature and mean skin temperature (from 12 sites) were measured. Subjects were seated in 37 degrees C water which was gradually warmed until sweating occurred (sweat rate increased above 50 g.m-2.h-1). The water was then cooled gradually until thresholds for vasoconstriction (onset of sustained decrease in fingertip blood flow) and shivering (sustained elevation in metabolism) were determined. Thresholds were then referred to as the core temperature, adjusted to a designated mean skin temperature of 33 degrees C. RESULTS: High dose clonidine similarly decreased the adjusted core temperature thresholds for vasoconstriction by 1.16 +/- 0.30 degrees C and for shivering by 1.63 +/- 0.23 degrees C (P < 0.01). The dose response effects were linear for both cold responses with vasoconstriction and shivering thresholds decreasing by 0.13 +/- 0.05 and 0.19 +/- 0.09 degree C.microgram-1 respectively (P < 0.0001). The sweating threshold was unaffected by clonidine, however the interthreshold range between sweating and vasoconstriction thresholds increased from control (0.19 +/- 0.48 degree C) to high dose clonidine (1.31 +/- 0.54 degrees C). CONCLUSION: The decreases in core temperature thresholds for cold responses and increased interthreshold range are consistent with the effects of several anaesthetic agents and opioids and is indicative of central thermoregulatory inhibition.     

Modulation detection interference in cochlear implant subjects

The aim of this study was to determine whether detection thresholds for amplitude modulated signals on a single electrode were influenced by a masking modulation on a second electrode in cochlear implant users. Data were collected from four post-linguistically deafened subjects using the Cochlear Limited prosthesis. Investigated were the effects of the spatial separation between test and masker electrodes, 0 to 5 electrodes (0 to 3.75 mm), and the amount of masking modulation: 24%, 48%, 72%, and 96% above detection thresholds. Initially, modulation detection thresholds for stimulation on a single electrode without masking modulation were obtained for a set of six electrodes in the middle of the array. Modulation detection thresholds on a fixed test electrode were then obtained with unmodulated and modulated masking on a second electrode, which was one of the six electrodes in the initial study. In both studies, thresholds were measured for modulated pulse duration at the modulation frequencies of 10-200 Hz. In the first study, the shape of the detection thresholds as a function of modulation frequency, the temporal modulation transfer function, generally resembled a low-pass filter for two subjects. For the other two subjects, the functions were relatively flat across modulation frequencies. In the second study, unmodulated masking resulted in a small elevation in detection thresholds across electrodes. Modulation detection interference (MDI), the difference between thresholds for the modulated maskers and the unmodulated masker, was greater for larger amounts of masking modulation than for smaller amounts of masking modulation. For three of the four subjects, MDI was higher for smaller spatial separations between the two electrodes than for larger spatial separations suggesting that a portion of MDI may be due to overlap of neural excitation distributions produced by stimulation on two electrodes in close proximity on the array.     

Bone conduction speech audiometry in normal subjects

The present study was designed to investigate: (1) the relationship among bone conduction (BC) pure tone averages, BC speech reception thresholds (SRTs), and BC speech detection thresholds for normal subjects; (2) short term reliability of BC SRTs; and (3) characteristics of the articulation functions for spondees obtained by bone conduction. Twenty-five normal-hearing young adults participated. The data revealed that BC SRT-pure tone average and SRT-speech detection threshold relationships are essentially the same as for air conduction. A comparison of the articulation functions for air conduction and BC revealed no practical difference between the two modes of stimulus presentation.     

Detection of silent intervals between noises activating different perceptual channels: some properties of "central" auditory gap detection

This article describes four experiments on gap detection by normal listeners, with the general goal being to examine the consequences of using noises in different perceptual channels to delimit a silent temporal gap to be detected. In experiment 1, subjects were presented with pairs of narrow-band noise sequences. The leading element in each pair had a center frequency of 2 kHz and the trailing element's center frequency was parametrically varied. Gap detection thresholds became increasingly poor, sometimes by up to an order of magnitude, as the spectral disparity was increased between the noise bursts that marked the gap. These data suggested that gap-detection performance is impoverished when the underlying perceptual timing operation requires a comparison of activity in different perceptual channels rather than a discontinuity detection within a given channel. In experiment 2, we assessed the effect of leading-element duration in within-channel and between-channel gap detection tasks. Gap detection thresholds rose when the duration of the leading element was less than about 30 ms, but only in the between-channel case. In experiment 3, the gap-detection stimulus was redesigned so that we could probe the perceptual mechanisms that might be involved in stop consonant discrimination. The leading element was a wideband noise burst, and the trailing element was a 300-ms bandpassed noise centered on 1.0 kHz. The independent variable was the duration of the leading element, and the dependent variable was the smallest detectable gap between the elements. When the leading element was short in duration (5-10 ms), gap thresholds were close to 30 ms, which is close to the voice onset time that parses some voiced from unvoiced stop consonants. In experiment 4, the generality of the leading-element duration effect in between-channel gap detection was examined. Spectrally identical noises defining the leading and trailing edges of the gap were presented to the same or to different ears. There was a leading-element duration effect only for the between channel case. The mean gap threshold was again close to 30 ms for short leading-element durations. Taken together, the data suggest that gap detection requiring a temporal correlation of activity in different perceptual channels is a fundamentally different task to the discontinuity detection used to execute gap detection performance in the traditional, within-channel paradigm.     

Effect of uncoupling NO/cGMP pathways on carbachol- and CCK-stimulated Ca2+ entry and amylase secretion from the rat pancreas

The aims of this cross-sectional comparative study was to compare the results of Semmes-Weinstein monofilament testing (SWM) and moving 2-point discrimination (M2PD) with four tests of functional sensibility: recognition of objects, discrimination of size and texture and detection of dots. Ninety-eight leprosy in- and outpatients at Green Pastures Hospital in Pokhara, Nepal were tested with each of the above tests and the results were compared to see how well they agreed. Using the tests of functional sensibility as reference points, we examined the validity of the SWM and M2PD as predictors of functional sensibility. There was definite, but only moderate correlation between thresholds of monofilaments and M2PD and functional sensibility of the hand. A normal result with the SWM and/or M2PD had a good predictive value for normal functional sensibility. Sensitivity was reasonable against recognition of objects and discrimination of textures as reference tests (80-90% and 88-93%), but poor against discrimination of size and detection of dots (50-75% and 43-65%). Specificity was high for most combinations of SWM or M2PD with any of the tests of functional sensibility (85-99%). Above a monofilament threshold of 2 g, the predictive value of an abnormal test was 100% for dot detection and 83-92% for textural discrimination. This indicates that impairment of touch sensibility at this level correlates well with loss of dot detection and textural discrimination in patients with leprous neuropathy. For M2PD the pattern was very similar. Above a threshold of 5 mm, 95-100% of affected hands had loss of dot detection and 73-80% had loss of textural discrimination. Monofilament testing and M2PD did not seem suitable as proxy measures of functional sensibility of the hand in leprosy patients. However, a normal threshold with monofilaments and/or M2PD had a good predictive value for normal functional sensibility. Above a monofilament threshold of 2 g and/or a M2PD threshold of 5 mm, textural discrimination was abnormal in most hands.     

Proprioception acts as the main source of input in human S-I activation experiments: a functional MRI study

During tactile exploration cells in human somatosensory cortex S-I receive input from skin receptors and from proprioceptive feedback. To study the extent to which these sources contribute to cell activation we used functional magnetic resonance imaging (fMRI) in order to visualize the spatial extent and amplitude of activation in S-I during active finger movement and passive stimulation of finger tips. In all subjects (n = 6) we measured activation elicited by unilateral single finger tapping (active task) and mechanical stimulation of the palm of the index finger (passive task). In the finger tapping condition all subjects showed a strict contralateral activation of somatosensory cortex S-I and motor cortex M-I. In the passive stimulation experiment we found activation of the contralateral somatosensory cortex S-I only. Although subjects were trained to perform the finger movement with the same frequency and pressure in comparison to the passive stimulation, the activation within S-I induced by finger movements was always significantly larger than that induced by passive stimulation. This result implies that activation of somatosensory cortex originates to a large extent from proprioception while tactile input plays a minor role in S-I excitation.     

Citric acid-induced cough thresholds in normal subjects, patients with bronchial asthma, and smokers

Several challenge procedures have been developed to characterize the cough reflex in patients with airway diseases. This study was performed to compare the interindividual range of cough sensitivity in asthmatic and normal subjects as well as smokers using an identical method. Sixteen normal subjects, 20 patients with mild bronchial asthma, 6 patients with moderate to severe bronchial asthma, 9 current smokers, and 7 occasional smokers were included. In all subjects, methacholine challenges and standardized citric acid challenges were performed. Sensitivity of the cough reflex was expressed as cough threshold, i.e., as concentration at which coughing occurred. Reproducibility was assessed in 23 subjects. Within a concentration range of 0.625-320.0 mg/ml, inhaled citric acid caused cough in all subjects. Geometric mean (range) cough threshold was 13 (2.5-160) in normal subjects, 14 (5-40) in patients with mild, and 32 (20-40) mg/ml in patients with moderate to severe asthma, 40 (20-80) in current smokers, and 119 (80-160) in occasional smokers. Cough thresholds were reproducible within one doubling concentration. In normal subjects and patients with mild bronchial asthma, thresholds were not significantly different from each other but lower than those of the other groups (p<0.05 each). Cough thresholds in smokers and patients with moderate to severe asthma did also not differ significantly and were lower than in occasional smokers (p<0.05). There was no significant correlation between cough threshold, baseline FEV subset1 , and methacholine responsiveness. Our data indicate that (1) subjects with mild asthma showed on average similar cough thresholds as normal subjects, (2) there was a large variation in cough thresholds within groups, (3) the reproducibility of cough thresholds was within one doubling concentration, (4) cough thresholds did not correlate with methacholine responsiveness or baseline airway tone. In view of the prevalence of cough as a symptom of bronchial asthma, it appears that the determination of citric acid-induced cough thresholds does not yield additional diagnostic information in these subjects.     

Nasal lavage as tool for health effect assessment of photochemical air pollution

In order to achieve esthetically more satisfying results, it has been proposed to place ITI implants with their border between the rough and smooth surfaces below the level of the alveolar crest, thereby obtaining a submucosally located implant shoulder following healing. The aim of the present experimental study was to clinically and radiographically evaluate the tissue response to the placement of one-stage transmucosal implants with the border between the rough and the smooth surfaces sunk by 1 mm into a subcrestal location. 11 patients underwent comprehensive dental care including the placement of 2 implants of the ITI Dental Implant System in the same quadrant (test and control). Randomly assigned control implants were placed according to the manufacturer's instructions, i.e. the border between the rough titanium plasma-sprayed and the smooth polished surfaces precisely at the alveolar crest. At the test implant the apical border of the polished surface was placed approximately 1 mm below the alveolar crest. Probing bone levels were assessed at implant placement (baseline), 4 and 12 months later. Modified plaque and modified gingival indices were recorded at 1, 2, 3, 4 and 12 months. Clinical probing depth and "attachment" levels were measured at 4 and 12 months. All parameters were assessed at 6 sites around each implant. The mean for each implant was calculated and used for analysis. The Wilcoxon matched pairs signed rank test and the Student t-test were applied to detect differences over time and between the test and control implants. At baseline, a mean difference in probing bone level of -0.86 mm (SD 0.43 mm, p < 0.05) was found between test and control implants with the test implants being placed more deeply. Both test and control implants lost a significant amount of clinical bone height during the first 4 months (test 1.16 mm, p < 0.05; control 0.58 mm, p < 0.05). However, only the test implants significantly lost clinical bone height from 4-12 months (test 1.04 mm, p < 0.05; control 0.45 mm, p = 0.08). Overall, the test implants lost 2.26 mm and the control implants 1.02 mm of bone height during the first year of service. On the average, the test implants demonstrated a bone level of 0.38 mm lower than the controls at 12 months. Except for the modified gingival index at 4 months (mean difference 0.21, SD 0.19, p < 0.05), no clinical parameters yielded significant differences between test and control implants at any time. It is concluded that in addition to the crestal bone resorption occurring at implants placed under standard conditions, the bone adjacent to the polished surface of more deeply placed ITI implants is also lost over time. From a biological point of view, the placement of the border between the rough and the smooth surfaces into a subcrestal location should not be recommended.     

The "callus-thenics" of touching.

Studied 8 undergraduates to provide an experimental test of the skin deformation model of tactile roughness and to examine the relative effectiveness of various tactile exploration strategies. Ss made magnitude estimates of the roughness of grooved aluminum plates presented at 2 different forces, using the 3 middle fingers of their writing hand, 1 at a time. Perceived roughness increased as a function of increasing groove width, increasing force, and finger (in the order index, middle, and ring). The effect of finger was predicted on the basis of differential callus thickness on the fingertip, and provided support for the skin deformation model proposed by M. M. Taylor and S. J. Lederman (see record 1975-10788-001). Discrimination with the index finger was better than when either the middle or ring finger was used, although there were no differences in the reliability of the judgments. The finding that the index finger was the most discriminating and likely to be the most highly calloused argues against a simple reduced sensitivity explanation of the effect of increased callus on perceived roughness. The merits of both perceptual learning and sensory explanations for the finger discrimination differences are discussed. Implications for procedures used to improve texture discrimination in young blind children are considered. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of systemic versus topical nonsteroidal anti-inflammatory drugs on postexercise jaw-muscle soreness: a placebo-controlled study

Certain types of jaw-muscle pain may be managed with pharmacologic treatment. This study evaluated the effect of topical and systemic nonsteroidal anti-inflammatory drugs on acute postexercise jaw-muscle soreness. Ten men without temporomandibular disorders performed six 5-minute bouts of submaximal eccentric jaw exercise. The outcome variables were pressure pain thresholds and pain tolerance thresholds at the masseter muscles, and maximum voluntary occlusal force. Surface electromyography from the masseter muscles was used to assess the development of muscle fatigue during the exercise period. Three treatment modalities were tested in a placebo-controlled, double-blind approach: (A) placebo gel and placebo tablets; (B) nonsteroidal anti-inflammatory drug gel (2 g, 5% ibuprofen) and placebo tablets; and (C) placebo gel and nonsteroidal anti-inflammatory drug tablets (400 mg ibuprofen). The subjects used their medication 3 times a day for 3 days in the postexercise period. In the exercise period, the mean power frequency of the electromyography signal, pressure pain threshold, pain tolerance threshold, and maximum voluntary occlusal force decreased significantly (analysis of variance, P < .01). In the postexercise period, the effect of treatment on pressure pain thresholds was significant (F[2,9] = 4.41, P = .02). On day 3, treatment with topical nonsteroidal anti-inflammatory drugs was associated with significantly higher pressure pain thresholds as compared to treatment with systemic nonsteroidal anti-inflammatory drugs (P < .05) and placebo (P < .05). Treatment effects on pain tolerance thresholds and on maximum voluntary occlusal force were nonsignificant. The results demonstrated that repeated eccentric jaw exercise caused muscle fatigue and low levels of postexercise pain and soreness. Topical nonsteroidal anti-inflammatory drugs seem to have some advantages over systemic nonsteroidal anti-inflammatory drugs for management of exercise-induced jaw-muscle pain.