Effects of box handle position and carrying range on bi-manual carrying capacity for females

This study utilizes a psychophysical approach to examine the effects on carrying capacity for bi-manual carrying tasks involving different handle positions and carrying ranges. A total of 16 female subjects participated in the experiment in groups of two people, and each group of subjects performed the tasks in a random order with 12 different combinations of carrying task. The independent variables are handle position (upper, middle, lower) and carrying range (F–F: floor height carried to floor height, F–W: floor height carried to waist height, W–W: waist height carried to waist height, W–F: waist height carried to floor height), the dependent variable is the maximum acceptable carried weight (MAWC), heart rate (HR), and the rating of perceived exertion (RPE). The results show that the handle position has a significant effect on MAWC and overall RPE but no significant effect on HR. Carrying range has a significant effect on the MAWC and HR, but no significant effect on overall HR. The handle position and carrying range have a significant interaction on the MAWC and HR. The RPE for different body parts shows significant differences, and the hands feel the most tired. Overall, this study confirms that the lower handle position with the W–W carrying range is the best combination for a two-person carrying task.     

The anatomical locus of T-junction processing

Inhomogeneous surrounds can produce either asymmetrical or symmetrical increment/decrement induction by orienting T-junctions to selectively group a test patch with surrounding regions [Melfi, T., & Schirillo, J. (2000). T-junctions in inhomogeneous surrounds. Vision Research, 40, 3735-3741]. The current experiments aimed to determine where T-junctions are processed by presenting each eye with a different image so that T-junctions exist only in the fused percept. Only minor differences were found between retinal and cortical versus cortical-only conditions, indicating that T-junctions are processed cortically.     

Spatial-frequency-related efficacy of visual stabilisation of posture

The present study investigates the efficacy of visual stabilisation of posture for different spatial frequencies of a visual stimulus. Circular sine wave gratings were used to analyse the correlation between perception of motion in depth and stabilisation of fore-aft sway by the mechanism of detecting changes in target size. Body sway was recorded by a force-measuring platform (series A) and, in addition, by simultaneous tracking of infrared markers fixed to the subject’s body (series B). Mean velocity and amplitude (RMS) of body sway were calculated in both sagittal (a–p) and lateral (l–r) planes. Sagittal sway was of least magnitude when viewing contrast gratings with lowest thresholds, whereas higher thresholds resulted in increasing sway parameters. As intended by the design of the stimuli, sagittal sway was correlated closer with the stabilising effect exerted by the different stimuli than was lateral sway. Sway velocity was reduced more efficiently, however, with a lower correlation with the psychophysical transfer function, than was RMS sway. Since sway velocity measured by the platform is suggested to depend to a greter extent on dynamic muscle forces generated at each individual body site the results indicate that visual information can be used to reduce and thereby optimise dynamic muscle action (sway velocity) even though static body sway is either not or less reduced. A comparable economisation of sway velocity but not of RMS sway was also seen at the end of posture investigations, indicative of positive training effects. Received: 28 February 1997 / Accepted: 2 March 1998     

小儿耳蜗植入后电诱发复合动作电位的阈值及其临床应用

目的　研究应用神经反应遥测 (neuralresponsetelemetry ,NRT)技术 ,测试电诱发复合动作电位 (electrically evokedcompoundactionpotential,ECAP)阈值以指导小儿人工耳蜗映射调图的策略与时机。方法　应用NRT3 0软件对幅值增长函数进行线性拟合 ,确定ECAP阈值。比较 6例儿童植入者在术后 1、2、3个月ECAP阈值的变化 ,同时比较 7例儿童术中、术后ECAP阈值的差异。结果ECAP幅值增长函数在接近阈值或进入饱和时不再呈线性。术后ECAP阈值保持稳定。各导电极的术中ECAP阈值比术后阈值平均高约 15CL ,二者有显著性相关 (R2 =0 915 4)。结论　应选取幅值增长函数的直线段部分进行拟合以确定ECAP阈值。术后应用ECAP阈值指导小儿映射调图时 ,测试一次ECAP阈值即可。术中ECAP阈值可用作开机时映射图的C值     

Does throbbing pain have a brain signature?

Pain sometimes has a throbbing, pulsating quality, particularly when it is severe and disabling. We recently challenged the presumption that this throbbing quality is a sensory experience of arterial pulsations, but were unable to offer an alternative explanation for its rhythmic character. Here we report a case study of a woman with a history of daily headache consistent with the diagnosis of chronic migraine, but whose throbbing quality persisted long after the resolution of the headache. This chronic, daily, and persistent throbbing sensation, in the absence of headache pain, prompted closer examination for its neurophysiological correlate. By simultaneously recording the subjective report of the throbbing rhythm, arterial pulse, and high-density electroencephalogram, we found that the subjective throbbing rate (48 ± 1.7 beats per minute) and heart rate (68 ± 2 beats per minute) were distinct, in accord with our previous observations that the 2 are unrelated. On spectral analysis of the electroencephalogram, we found that the overall amount of activity in the alpha range (8 to 12 Hz), or alpha power, increased in association with greater throbbing intensity. In addition, we also found that the rhythmic oscillations of overall alpha power, the so-called modulations of alpha power, coincided with the timing of the throbbing rhythm, and that this synchrony, or coherence, was proportional to the subjective intensity of the throbbing quality. This index case will motivate further studies whose aim is to determine whether modulations of alpha power could more generally represent a neurophysiological correlate of the throbbing quality of pain.     

Visual information throughout a reach determines endpoint precision

People make rapid, goal-directed movements to interact with their environment. Because these movements have consequences, it is important to be able to control them with a high level of precision and accuracy. Our hypothesis is that vision guides rapid hand movements, thereby enhancing their accuracy and precision. To test this idea, we asked observers to point to a briefly presented target (110 ms). We measured the impact of visual information on endpoint precision by using a shutter to close off view of the hand 50, 110 and 250 ms into the reach. We found that precision was degraded if the view of the hand was restricted at any time during the reach, despite the fact that the target disappeared long before the reach was completed. We therefore conclude that vision keeps the hand on the planned trajectory. We then investigated the effects of a perturbation of target position during the reach. For these experiments, the target remained visible until the reach was completed. The target position was shifted at 110, 180 or 250 ms into the reach. Early shifts in target position were easily compensated for, but late shifts led to a shift in the mean position of the endpoints; observers pointed to the center of the two locations, as a kind of best bet on the position of the target. Visual information is used to guide the hand throughout a reach and has a significant impact on endpoint precision.     

Adaptation of the Sniffin’ Sticks Test in South-Kivu

AimThe “Sniffin’ Sticks” test is widely used in Europe as a standard test to assess olfaction. Several culturally-adapted versions have been developed. However, no version adapted to Sub-Saharan African populations exists. The aims of the present study were (1) to assess the applicability of the Sniffin’ Sticks test in the population of South Kivu (DR Congo), and (2) to develop a culturally adapted version with normative values.Materials and methodsIn a first study, 157 volunteers were tested with the original Sniffin’ Sticks test. Based on these results, we selected odors that were poorly recognized in the identification test and replaced them by culturally adapted odors. In a second study, we assessed the modified version of the Sniffin’ Sticks test in 150 volunteers and defined normative values.ResultsIn the first study, we found that olfactory function (threshold-discrimination-identification: TDI score) significantly decreased with age and was better in females. Five odors were poorly recognized and were replaced by culturally adapted odors. In the second study, we found that this adapted version led to a higher rate of correctly identified odors. We defined normative values for the South-Kivu population (TDI score: 18–35 years: 30.4 ± 6.0; 36–55 years: 26.2 ± 5.3; > 55 years: 25.6 ± 5.0).ConclusionThis culturally adapted version of the Sniffin’ Sticks test is culturally adapted to the South Kivu population. The normative values will provide the basis for clinical evaluation of pathologic subjects.     

Deficiency in endogenous modulation of prolonged heat pain in patients with Irritable Bowel Syndrome and Temporomandibular Disorder

Females with Irritable Bowel Syndrome (IBS) and Temporomandibular Disorder (TMD) are characterized by enhanced sensitivity to experimental pain. One possible explanation for this observation is deficiencies in pain modulation systems such as Diffuse Noxious Inhibitory Control (DNIC). In a few studies that used brief stimuli, chronic pain patients demonstrate reduced DNIC. The purpose of this study was to compare sensitivity to prolonged heat pain and the efficacy of DNIC in controls to IBS and TMD patients. Heat pain (experimental stimulus; 44.0–49.0 °C), which was applied to left palm, was continuously rated during three 30-s trials across three separate testing sessions under the following conditions: without a conditioning stimulus; during concurrent immersion of the right foot in a 23.0 °C (control); and during noxious cold immersion in a (DNIC; 8.0–16.0 °C) water bath. Compared to controls, IBS and TMD patients reported an increased sensitivity to heat pain and failed to demonstrate pain inhibition due to DNIC. Controls showed a significant reduction in pain during the DNIC session. These findings support the idea that chronic pain patients are not only more pain sensitive but also demonstrate reduced pain inhibition by pain, possibly because of dysfunction of endogenous pain inhibition systems.     

Internal validity of inter‐digital web pinching as a model for perceptual diffuse noxious inhibitory controls‐induced hypoalgesia in healthy humans

Hot and ice‐water immersions are commonly used for heterotopic noxious counter‐stimulation (HNCS) in investigations on endogenous pain modulation. However, coincident sympathetic thermoregulatory activity does not allow to differentiate between perceptual hypoalgesia related to baroreflex sensitivity (BRS) or diffuse noxious inhibitory controls (DNIC). The present study analysed the internal validity of another supposedly less confounded tonic pain model (inter‐digital web pinching; IWP) regarding its potential as DNIC trigger. We performed a randomized controlled study in 24 healthy gender‐matched drug‐free volunteers aged 21–54 (median 25) years. The study protocol comprised the assessment of mechanical and thermal perceptual wind‐up before and after an IWP (15N) or hot water immersion trial (HIT; 47.5°C) of 2min duration. Wind‐up was induced either by 10 repetitive (1Hz) contact heat (max. 49°C; 5×5mm thermode) or ballistic impact stimuli (0.5g at 9m/s) on the phalanges of the non‐dominant hand. Cardiovascular activity, pain experience and corrugator muscle activity were continuously monitored. Although both HNCS forms produced a similar pain experience (45% of scale), a more pronounced cardiovascular activity was observable for the HIT (P<0.01). This indicates a higher baroreceptor activity and stronger contamination of painful water immersion by BRS‐related hypoalgesia. Regardless of pain modality, wind‐up was significantly reduced by HNCS, although this was stronger for painful water immersion than for noxious pinching (P<0.01). The HNCS types allow a differentiation between BRS‐related and DNIC‐like hypoalgesia. IWP proved its validity for DNIC induction, being practically non‐confounded by BRS.     

Features and the ‘primal sketch’

This review is concerned primarily with psychophysical and physiological evidence relevant to the question of the existence of spatial features or spatial primitives in human vision. The review will be almost exclusively confined to features defined in the luminance domain. The emphasis will be on the experimental and computational methods that have been used for revealing features, rather than on a detailed comparison between different models of feature extraction. Color and texture fall largely outside the scope of the review, though the principles may be similar. Stereo matching and motion matching are also largely excluded because they are covered in other contributions to this volume, although both have addressed the question of the spatial primitives involved in matching. Similarities between different psychophysically-based model will be emphasized rather than minor differences. All the models considered in the review are based on the extraction of directional spatial derivatives of the luminance profile, typically the first and second, but in one case the third order, and all have some form of non-linearity, be it rectification or thresholding.