Fibromyalgia Patients Are Not Only Hypersensitive to Painful Stimuli But Also to Acoustic Stimuli

Fibromyalgia is a chronic widespread pain syndrome associated with hypersensitivity to nociceptive stimuli. This increased sensitivity of FM patients has been associated with central sensitization of dorsal horn neurons. Increasing evidence, however, suggests that the mechanisms of FM hypersensitivity not only affect pain but include light, smell, and sound. We hypothesized that supraspinal augmentation of sensory input including sound represent a hallmark of FM. We tested 23 FM patients and 28 healthy controls (HC) for sensory augmentation of nociceptive and non-nociceptive sensations: For assessment of nociceptive augmentation we used sensitivity adjusted mechanical and heat ramp & hold stimuli and for assessment of sound augmentation, we applied wideband noise stimuli using a random-staircase design. Quantitative sensory testing demonstrated increased heat and mechanical pain sensitivity in FM participants (P < .001). The sound pressures needed to report mild, moderate, and intense sound levels were significantly lower in FM compared to HC (P < .001), consistent with auditory augmentation.FM patients are not only augmenting noxious sensations but also sound, suggesting that FM augmentation mechanisms are not only operant in the spinal cord but also in the brain. Whether the central nervous system mechanisms for auditory and nociceptive augmentation are similar, needs to be determined in future studies.PerspectiveThis study presents QST evidence that the hypersensitivity of FM patients is not limited to painful stimuli but also to innocuous stimuli like sound. Our results suggest that abnormal brain mechanisms may be responsible for the increased sensitivity of FM patients.     

Electrophysiological Effects of Monophasic and Biphasic Stimuli in Normal and Infarcted Dogs

Though some biphasic waveforms significantly decrease the energy required for defibrillation, little is known about the effect of biphasic stimulation on the determination of other electrophysiological parameters in normal and infarcted hearts. To evaluate this, nine normal dogs and 12 dogs with myocardial infarction had activation threshold (AT), effective refractory period (ERP), strength-interval curves, and ventricular fibrillation threshold (VFT) determined with constant current stimulation to a pair of right ventricular plunge electrodes, and upper limit of vulnerability (ULV) and defibrillation threshold (DFT) determined with truncated exponential shocks delivered to a pair of wire electrodes coiled to contour the right and left ventricular epicardium. Each electrophysiological parameter was determined with a 5.5 msec monophasic and 5.5-msec biphasic (3.5 msec first phase) waveform. Though AT and VFT were not significantly different for the two waveforms, the ERP was significantly longer, the strength-interval curve shifted rightward, and the threshold for repetitive responses higher for biphasic stimuli. Compared to the monophasic waveform, the ULV and DFT were significantly decreased in a parallel fashion for the biphasic waveform. Neither the presence nor size of myocardial infarction significantly affected any of the measured electrophysiological parameters. In six additional dogs, sigmoid defibrillation probability curves were constructed from biphasic shocks of four energies including that of the DFT and ULV. The ULV energy predicted an effective dose that defibrillated 97% of the time (range 90%-100%). In conclusion, the increased defibrillation efficacy of the biphasic waveform is independent of its ability to activate fully repolarized myocardium and cannot be explained by a greater ability of biphasic waveforms to activate partially depolarized tissue. The parallel decrease in the ULV and DFT for biphasic stimulation and the finding that the ULV energy defibrillates with a high probability of success suggest similar underlying mechanisms for the ULV and defibrillation.     

Emotion Congruent Facilitation of Attention when Processing Anxious Stimuli

Researchers using spatial attention tasks have shown that anxious individuals are quick to orient to threatening information, but have difficulty disengaging attention from that location. We extended this line of research by investigating the influence of anxiety on attention across time rather than space. It was found that anxious words imbedded in a rapidly presented stream of distractors were correctly identified more often than neutral words, regardless of the emotional state of the participant. Having identified the first target in the stream, participants were able to detect a second target sooner when the first target was an anxious word and the participant was experiencing anxiety in comparison to conditions in which the first target was neutral or the participant was not anxious. The rapid recovery of the attentional system when there was emotional congruence between the state of the individual and the attended information, points to the unique influence that anxiety has on attention across time in comparison to its influence on spatial attention.     

Migraine is Associated With Altered Processing of Sensory Stimuli

Migraine is associated with derangements in perception of multiple sensory modalities including vision, hearing, smell, and somatosensation. Compared to people without migraine, migraineurs have lower discomfort thresholds in response to special sensory stimuli as well as to mechanical and thermal noxious stimuli. Likewise, the environmental triggers of migraine attacks, such as odors and flashing lights, highlight basal abnormalities in sensory processing and integration. These alterations in sensory processing and perception in migraineurs have been investigated via physiological studies and functional brain imaging studies. Investigations have demonstrated that migraineurs during and between migraine attacks have atypical stimulus-induced activations of brainstem, subcortical, and cortical regions that participate in sensory processing. A lack of normal habituation to repetitive stimuli during the interictal state and a tendency towards development of sensitization likely contribute to migraine-related alterations in sensory processing.     

Altered Neurocognitive Processing of Tactile Stimuli in Patients with Complex Regional Pain Syndrome

Chronic pain in complex regional pain syndrome (CRPS) has been linked to tactile misperceptions and deficits in somatotopic representation of the affected limb. In this study, we identify altered cognitive processing of tactile stimuli in CRPS patients that we propose marks heterogeneity in tactile decision-making mechanisms. In a case-control design, we compared middle- and late-latency somatosensory evoked potentials in response to pseudorandomized mechanical stimulation of the digits of both hands (including CRPS-affected and nonaffected sides) between 13 CRPS patients and 13 matched healthy controls. During a task to discriminate the digit simulated, patients (compared with controls) had significantly lower accuracy and slowed response times but with high between-subject variability. At middle latencies (124–132?ms), tactile processing in patients relative to controls showed decrements in superior parietal lobe and precuneus (that were independent of task demands) but enhanced activity in superior frontal lobe (that were task-dependent). At late latencies, patients showed an augmented P300-like response under task demands that localized to the supplementary motor area. Source activity in the supplementary motor area correlated with slowed response times, although its scalp representation intriguingly correlated with better functioning of the affected limb, suggesting a compensatory mechanism. Future research should investigate the clinical utility of these putative markers of tactile decision-making mechanisms in CRPS.

声学定量技术检测左冠分支急性闭塞再通后左心室功能的实验研究

目的应用声学定量技术探讨实验犬左冠分支闭塞再通后的左心室整体功能改变。方法对7只实验犬使用冠状动脉球囊扩张技术制作左冠分支急性闭塞及再通动物模型;应用超声声学定量技术检测急性闭塞30min再通、90min再通、300min再通的左心室收缩、舒张功能。结果左冠分支急性闭塞30min再通后与闭塞前相比,射血分数0.50±0.11vs0.48±0.10、左室峰值射血率(6.95±0.73)EDV/svs(5.93±0.67)EDV/s,P>0.05,无显著差异,左室峰值充盈率(4.55±2.85)EDV/svs(6.06±2.69)EDV/s,P<0.05;左冠分支急性闭塞90min再通后与闭塞前相比,射血分数0.44±0.18vs0.48±0.10、左室峰值射血率(4.88±1.32)EDV/svs(5.93±0.67)EDV/s,P均<0.05;左室峰值充盈率(3.86±3.15)EDV/svs(6.06±2.69)EDV/s,P<0.01;但与300min再通相比,以上测值均明显恢复。结论(1)成功制作了冠状动脉急性闭塞再通的动物模型;(2)左冠分支急性闭塞30min再通后仅有舒张功能轻度损害;而闭塞90min再通后左室收缩功能、舒张功能均有损害,但较300min再通有明显改善。     

多普勒不同频率探头测定心输出量的实验研究

本文报道在9只开胸犬动物模型上观察不同频率探头(2.5MHz、3.5MHz、5.0MHz)测得的主动脉流量与有创电磁流量计法测值的关系。结果显示:三种频率探头测得的流量与电磁流量计测值密切相关(γ=0.90～0.96),但2.5MHz探头测值与电磁流量计测值相比较有显著高估(P<0.05)。提示:1.用多普勒方法无创测定心输出量是可行和可靠的;2.用多普勒法做血流定量分析时。探头频率的选择影响所测结果的准确性。探头频率选择原则为fo=30MHz/最大取样深度(cm)。     

去骨瓣减压术治疗急性大面积脑梗死临床观察

目的总结去骨瓣减压术治疗急性大面积脑梗死的手术时机、疗效，确定手术意义。方法回顾性分析6例急性大面积脑梗死患者因病情进行性加重，早期行去骨瓣减压术的临床资料。结果5例存活，其中4例经过康复，Barthel指数在60分以上。1例高龄患者死于肺部感染。结论去骨瓣减压是抢救进行性加重大面积脑梗死患者的有效手段，并有益于患者神经功能的恢复。     

Effects of Different Pacing Modes on Left Ventricular Relaxation in Closed-Chest Dogs

Ventricular relaxation is an important determinant of ventricular filling; impaired relaxation may decrease cardiac output and stroke volume. Relaxation hos been shown to occur more quickly following beats with an increased extent of systolic fiber shortening. Since cardiac output and stroke volume are greater during atrioventricular (AV) sequential pacing than during ventricular pacing at identical heart rates, we reasoned that AV sequential pacing would improve relaxation. To assess this hypothesis we studied 11 dogs with chronic (1-3 months) complete heart block (CHB) induced by radiofrequency catheter ablation of the His bundle. Right and left heart pressures, thermodilution cardiac output, und single plane ventriculography were recorded during baseline rhythm (CHB), and VVI, and AV sequential pacing at a heart rate greater than the sinus rate. None had ventriculoatrial conduction. During AV sequential pacing, the AV interval was set at 150 msec. Cardiac output and stroke volume were significantly increased in the AV sequential compared to the VVI pacing mode. Left ventricular pressures, maximal positive and negative dP/dt, and the time constant (T) of isovolumic pressure decay were not different in the two modes. We conclude that despite increased stroke volume in the AV sequential pacing mode, relaxation is unchanged. We believe the lack of change in relaxation is due to nonuniform ventricular activation when depolarization is initiated at the right ventricular apex.     

Hemispheric asymmetries in eye-hand coordination

Manual asymmetries in limb kinematics and eye-hand coordination have usually been attributed to differences in online processing capabilities between the left and the right cerebral hemisphere. In the present fMRI experiment, we examined in right handers the brain areas involved in eye-hand coordination with either the left or the right hand. Although temporal and spatial accuracy was equal for left- and right-hand movements, manual asymmetries were found in behavioral and neurophysiologic data, suggesting an asymmetric mode of control for left vs. right eye-hand coordination. For left eye-hand coordination, peak velocity and saccade completion occurred earlier than for the contralateral movements, suggesting that there was more time needed for homing-in on the target. When using the right hand, there was more activation in occipital areas. This might indicate a more intense visual processing or visualization of the target locations. When using the left hand, there was more activation in sensorimotor areas, frontal areas and cerebellum. This might point toward more processing effort. Left-hand movements may be considered as more difficult than right-hand movements by right-handed participants. Alternatively and more likely, these findings might reflect a difference in attention or resources attributed to different aspects of the tasks because of the different functional specializations of both hand/hemisphere systems.     

Relationship between Sympathetic Skin Responses and Auditory Hypersensitivity to Different Auditory Stimuli

[Purpose] Auditory hypersensitivity has been widely reported in patients with autism spectrum disorders. However, the neurological background of auditory hypersensitivity is currently not clear. The present study examined the relationship between sympathetic nervous system responses and auditory hypersensitivity induced by different types of auditory stimuli. [Methods] We exposed 20 healthy young adults to six different types of auditory stimuli. The amounts of palmar sweating resulting from the auditory stimuli were compared between groups with (hypersensitive) and without (non-hypersensitive) auditory hypersensitivity. [Results] Although no group × type of stimulus × first stimulus interaction was observed for the extent of reaction, significant type of stimulus × first stimulus interaction was noted for the extent of reaction. For an 80 dB-6,000 Hz stimulus, the trends for palmar sweating differed between the groups. For the first stimulus, the variance became larger in the hypersensitive group than in the non-hypersensitive group. [Conclusion] Subjects who regularly felt excessive reactions to auditory stimuli tended to have excessive sympathetic responses to repeated loud noises compared with subjects who did not feel excessive reactions. People with auditory hypersensitivity may be classified into several subtypes depending on their reaction patterns to auditory stimuli.Key words: Auditory hypersensitivity, Sympathetic nervous system, Auditory stimuli     

Specialization for written words over objects in the visual cortex

The Visual Word Form Area (VWFA) is part of the left ventral visual stream that underlies the invariant identification of visual words. It remains debated whether this region is truly selective for words relative to common objects; why this particular part of the visual system is reproducibly engaged in reading; and whether reading expertise also relies on perceptual learning within earlier visual areas. In this fMRI study we matched written words and line-drawings of objects in luminance, contour length and number of features. We then compared them to control images made by scrambling procedures that kept local features intact. Greater responses to written words than to objects were found not only in the VWFA, but also in areas V1/V2 and V3v/V4. Furthermore, by contrasting stimuli reduced either to line junctions (vertices) or to line midsegments, we showed that the VWFA partially overlaps with regions of ventral visual cortex particularly sensitive to the presence of line junctions that are useful for object recognition. Our results indicate that preferential processing of written words can be observed at multiple levels of the visual system. It is possible that responses in early visual areas might be due to some remaining differences between words and controls not eliminated in the present stimuli. However, our results concur with recent comparisons of literates and illiterates and suggest that these early visual activations reflect the effects of perceptual learning under pressure for fast, parallel processing that is more prominent in reading than other visual cognitive processes.     

Heart Pacing in Dogs

My television experience began on an ordinary weekday when I was introduced to two very pleasant women from the BBC interested in making a programme about an animal hospital. At the time they had not decided on a definite location, but had a shortlist of three. It is no secret that their final choice was the Harmsworth Animal Hospital in Holloway, north London.     

Cataract Surgery in Dogs

Owners commonly present to the veterinary clinic with a complaint that their dog’s vision has reduced, or their dog’s eye(s) appear cloudy and subsequently our veterinary surgeons may diagnose them with having cataracts. Cataracts can form due to a number of reasons including heritage, diabetes mellitus, trauma or ocular disease. This article discusses what a cataract is, patient considerations and surgical removal. I will also discuss the post-operative care following phacoemulsification and what we can do to help with our client’s compliance in providing the best care for their pet in the immediate recovery period.