Impairment of movement initiation and execution but not preparation in idiopathic dystonia

Imaging studies have reported impaired activation of the striatum and their frontal projection sites in dsytonia, areas which are considered to play a role in motor preparation, movement initiation and execution. The aim of this study was to investigate the processes of motor preparation, response initiation and execution in patients with idiopathic torsion dystonia (ITD). We assessed 12 patients with ITD and 12 age-matched controls on a number of reaction time (RT) tasks that differed in degree of motor preparation possible. Subjects performed a visual simple RT (SRT) task, an uncued four-choice reaction time (CRT) task and a fully precued four-choice RT task. A stimulus 1-stimulus 2 (S1-S2) paradigm was used. The warning signal/precue (S1) preceded the imperative stimulus (S2) by either 0 ms (no warning signal or precue) 200 ms, 800 ms, 1,600 ms or 3,200 ms. The patients with ITD had significantly slower RTs and movement times than normals across all RT tasks. The unwarned SRT trials were significantly faster than the uncued CRT trials for both groups. For both groups, precued CRTs were significantly faster than the uncued CRTs. The results show that while response initiation and execution are significantly slower in patients with ITD than normals, movement preparation is not quantitatively or qualitatively different. The results are discussed in relation to previous imaging, behavioural and electrophysiological studies and models of fronto-striatal dysfunction in ITD.     

2010年我院178例药品不良反应报告分析

目的:通过对我院药物应用过程中不良反应的发生情况进行分析,为临床安全合理用药提供参考。方法:将我院2010年药品ADR上报表评价审核后,采用回顾性调查的统计分析方法,对患者的一般资料、给药途径、药品类别、剂型、药品不良反应临床表现等进行统计分析。结果:178例ADR报告中,约60%通过静脉滴注给药,涉及药物以抗感染药居首位,临床表现以皮肤及其附件最多共70例(39%),发生于用药30min以内共计71例(40%),严重不良反应报告15例(8.4%)。结论:不良反应的发生与药品种类、给药途径、患者年龄等因素相关,临床应加强开展药物的不良反应监测,警示严重不良反应,科学规避用药风险,促进临床安全、合理用药。     

肿瘤患者中不同中心静脉导管的临床应用及比较

目的对比两种不同中心静脉导管在肿瘤患者中的临床应用效果。方法145例肿瘤患者分为两组,使用中心静脉导管62例为A组,使用一次性无菌中心静脉导管穿刺包83例为B组,观察记录两组导管留置时间、导管相关性感染的感染率和不良反应的发生率及置管部位、操作技术、导管维护等情况。结果导管平均留置时间A组35d,B组39d,差异无显著性（P〉0．05）。导管相关性感染率A组14．52％,B组2．41％,差异有显著性（P〈0．05）。不良反应发生率A组11．29％,B组1．21％,差异显著（P〈0．05）,置管部位、操作技术、导管维护组间相比无显著区别。结论肿瘤科深静脉置管患者使用一次性无菌中心静脉导管穿刺包发生置管后导管相关性感染的感染率和不良反应的发生率低,在临床上值得推广使用。     

Covert attention in touch: behavioral and ERP evidence for costs and benefits

To investigate the mechanism underlying tactile spatial attention, reaction times (RTs) and event-related potentials (ERPs) were recorded in response to mechanical stimuli delivered to the hands. At the start of each trial cues indicated either the correct (valid) or incorrect (invalid) tactile stimulus location or were uninformative (neutral). RT costs (suppression of invalid compared to neutral trials) were found to be larger than benefits (enhancement of valid compared to neutral trials). ERPs showed that costs and benefits contribute equally to attentional modulations of the somatosensory N140 component, whereas these were largely due to costs at longer latencies. These results differ from the pattern of attentional ERP modulations previously found for vision and audition, where costs precede benefits, and therefore suggest that the mechanisms of attentional selectivity in touch might be different from attentional processes in other modalities.     

Sensory biases produce alternation advantage found in sequential saccadic eye movement tasks

In two-choice reaction time tasks, participants respond faster when the correct decision switches across consecutive trials. This alternation advantage has been interpreted as the guessing strategies of participants. Because the participants expect that the correct decision will switch across consecutive trials, they respond faster when this expectation is confirmed and they respond more slowly when it is disconfirmed. In this study, we evaluated the veracity of this expectancy interpretation. After replicating a long-lasting alternation advantage in saccadic reaction times (Experiment 1), we show that reducing the participants ability to guess with a challenging mental rotation task does not change the alternation advantage, which suggests that expectancy is not responsible for the effect (Experiment 2). Next, we used prosaccade and antisaccade responses to dissociate between the sensory and motor contributions of the alternation advantage (Experiment 3) and we found that the alternation advantage originates from sensory processing. The implications of these findings are discussed with regard to guessing strategies, sensory processing, and how these findings may relate to inhibition of return.Jillian H. Fecteau and Crystal Au contributed equally to this work     

Eye position and target amplitude effects on human visual saccadic latencies

Gaze shifts vary in the extent of eye and head contribution; a large amplitude and/or an eccentric ocular orbital starting position alter the participation of head movement in the shift. The interval between eye onset and head onset determines compensatory counterrolling before and after the shift and the extent of vestibular ocular reflex reduction during the shift. The latency of eye saccades in the head-fixed condition was measured with respect to target amplitude and orbital position in order to establish base-line operations of these two variables as they apply to the headfree condition. Eye movements were measured during single-step saccades in nine young adult humans. The target step, hereafter called a jump, started from three possible fixation lights; e.g., rightward saccades started from the midline (0°) or from -20 or -40° left of the midline, with a maximum amplitude of 80°. The latency of saccades starting from the primary position increased with jump amplitude (amplitude-latency relation). When the eye started eccentrically, the latency was decreased (orbital position-latency relation), with the largest jump amplitudes most affected. These changes can be related to active eye-head coordination. Thus, with a leftward maximal orbital eccentricity, compensatory eye rotation would be impossible with a rightward head movement; however, incorporating the orbital position-latency relation, the forward ocular saccade is expedited by 90 ms. Conversely, with a primary starting position, the ocular component of an 80° gaze saccade could be slowed 125 ms by incorporating the amplitude-latency relation, thus facilitating a head contribution to the gaze shift. The orbital position and amplitude-latency relations were prominent in those subjects with habitually large head contributions to the gaze shift and minimal in individuals with typically small head contributions.     

At what stage of manual visual reaction time does interhemispheric transmission occur: controlled or ballistic?

Interhemispheric transfer (IT) time through the corpus callosum can be measured with a manual reaction time (RT) to lateralized visual stimuli (the so-called Poffenberger paradigm) by subtracting mean RT of faster uncrossed hemifield-hand combinations (not requiring an IT) from slower crossed combinations (requiring an IT). That the corpus callosum is involved in IT has been demonstrated by its dramatic lengthening in patients with a section of the corpus callosum. However, it is still unclear whether the signal transmitted by the corpus callosum concerns perceptual or motor stages of RT. To try and cast light on this question, in a first experiment we tested normal subjects on a partially modified Poffenberger paradigm with stop trials intermingled with go trials. In the former, subjects are supposed to refrain from responding following a stop signal (stop-signal paradigm). This paradigm can tease apart the contribution of the controlled and ballistic stages to overall RT and, used together with the Poffenberger task, enables one to assess the stage at which IT occurs. The controlled stage lies before the point of no return, i.e. the point beyond which the response cannot be inhibited, and concerns perceptual and pre-motor processes, while the ballistic stage occurs after the point of no return and concerns the motoric aspect of the response. We found that the slower responses typically obtained in the crossed conditions were more likely to be inhibited than the faster uncrossed responses and this suggests that IT occurs prior to the point of no return. Since the precise locus of the point of no return is uncertain, in a second experiment we used response force as a dependent variable reflecting the activation of the motor cortex. We found that none of the force parameters studied differed between crossed and uncrossed conditions while the temporal parameters confirmed the presence of an advantage of the uncrossed combinations. Altogether these results suggest that callosal IT of visuomotor information occurs at the stage of controlled (perceptual and pre-motor) processes and rule out the possibility of an IT at the motoric stage.     

Detection rates of bacteria in chronic otitis media with effusion in children

This study was performed to investigate polymerase chain reaction-based detection of bacterial DNA in middle ear fluid and assess the correlation between the PCR-positive rate with several factors associated with middle ear effusion. The purpose was to gain a further understanding of bacterial infection as a major cause of otitis media with effusion. Of the 278 specimens of middle ear fluid, 39 (14%) tested positive by ordinary culture. The overall detection rate of bacterial DNA using the PCR method was 36.7% for middle ear effusion, and bacterial DNA detection rates of Hemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis in the middle ear effusion were 29.1%, 4.7% and 10.8%, respectively. The bacterial DNA detection rate was higher in ears with a history of acute otitis media than those without the history. High detection rates were observed in patients younger than 48 months who have had a higher tendency to present with acute otitis media. We concluded that PCR is a more sensitive method for the detection of bacteria in middle ear effusion than ordinary culture, and acute otitis media is a major contributor to the pathogenesis of otitis media with effusion.     

珠心算训练对儿童听心算过程的影响

目的探讨数字和纯音听觉刺激对珠心算训练儿童加法心算效率的影响。方法采用事件相关电位（ERP）方法,记录儿童加法听心算时的反应时和行为数据的正确率。结果经过珠心算训练的儿童加法听心算的潜伏期缩短、反应时加快、运算的正确率提高（P〈0．01）。结论珠心算训练儿童加法听心算过程加快,珠心算训练有利于提高儿童的数字认知和心算反应速度。