Movement-related potential measures of different modes of movement selection in Parkinson's disease

Movement-related potentials were recorded preceding self-paced voluntary movements in patients with Parkinson's disease and in healthy subjects of the same age group. We compared the Readiness Potential preceding joystick movements in a fixed direction and preceding joystick movements in freely selected directions. In normal subjects the Readiness Potential amplitude was higher preceding freely selected movements than preceding movements in a fixed direction. The Readiness Potential in Parkinson patients failed to be modified by the different modes of movement selection. The modulation of the Readiness Potential by different ways of preparing for movement might be due to the supplementary motor area (SMA) being more strongly engaged by tasks requiring internal control of movements than by tasks that are externally structured. The results suggest that this task-dependent variation of SMA activity is reduced in Parkinson's disease. A failing capacity to adapt SMA activity to different task demands has previously been suggested by evidence from positron emission tomography studies using similar tasks.     

脊髓手术中体感诱发电位监测的临床研究

报告３０例脊髓手术中体感诱发电位（ＳＥＰ）连续监测的临床研究结果。ＳＥＰ记录包括脊髓ＳＥＰ（ＳＳＥＰ）和皮层ＳＥＰ（ＳＣＥＰ）。麻醉药物对ＳＥＰ有一定程度影响，ＳＣＥＰ相对较大。认为，至少术中ＳＥＰ潜伏期延长不超过８％和波幅降低不超过５０％，不会引起术后并发症，超过该范围由于病例较少，尚不能肯定与预后的关系，需进一步探讨。     

Sparing of perceptual implicit memory despite suppression of the electrophysiological word repetition effect: a study with general anesthetic isoflurane.

OBJECTIVE: Much effort has been devoted to the search for the neurophysiological correlates of implicit memory. A commonly held view is that the early portion (250-500 ms) of the event-related potential (ERP) word repetition effect reflects processes important for perceptual implicit memory whereas the latter portion reflects processes implicated in explicit memory. It is, however, difficult to disentangle with certainty the relative contributions of each form of memory on ERPs since both forms co-exist in normal subjects. To dissociate ERP effect related to implicit and explicit memory, we used isoflurane sedation in normal subjects to suppress explicit remembering while sparing implicit memory. These ERPs were compared with those of non-medicated control subjects. METHODS: Thirteen subjects performed an incidental encoding task for words presented auditorily during the inhalation of a subanesthetic dose of isoflurane. After termination of isoflurane administration, we assessed free recall and recorded ERPs during a syllable completion task (implicit memory) and during a passive listening task (ERP repetition effect). Eleven non-medicated control subjects were tested in a similar manner. RESULTS: The controls showed robust early and late ERP repetition effect. The isoflurane group had implicit memory without free recall and showed no ERP repetition effect. CONCLUSIONS: These findings failed to show an association between any part of the repetition effect and perceptual implicit memory. The results are consistent with the view that processes linked to explicit memory contribute to the ERP repetition effect since there was a marked difference in free recall between the control and isoflurane groups. SIGNIFICANCE: The present study shows that the reversible alterations of memory by general anesthetics can be used to study the neurophysiological correlates of memory processes.     

Spectral characteristics of early receptor potential in congenital red-green color blindness

The spectral response curve (amplitude versus wavelength) of the R₂ of the early receptor potential (ERP) was studied in normal, protan, and deutan subjects. The R₂ amplitude peaked at 520nm in most normal subjects. The R₂ at long wavelengths was smaller than normal in protans and larger than normal in deutans when the maximum amplitudes were normalized to 100% at the peak. The ratio of the R₂ amplitude at 460 nm to that at 600 nm clearly differed between protans and deutans. The ERP and the rapid off-response, which is mainly due to the cessation of the late receptor potential, were recorded in the same subjects. The ratio of the sensitivity of the rapid off-response at 500 nm to that at 600 nm was correlated with the ratio of the R₂ amplitude at 460 nm to that at 600nm (correlation coefficient, 0.823, p < 0.001). This study, in conjunction with our previous study, indicates that the abnormality is in the outer segments of the cones in protans and deutans.     

精神分裂症患者事件相关电位P300改变对语词记忆能力的影响

目的探讨精神分裂症患者的语词记忆能力与认知电位之间的相互关系。方法对102例精神分裂症患者首先进行了听觉诱发电位P300测定，然后按有无P300潜伏期延长或/和波幅降低分为P300正常与异常组，再采用选择性提醒测验方法对其进行语词记忆测验。结果P300正常组30例在10次语词记忆测验中通过总例数28例，占93.3%，前6次通过的比例为56.7%；而P300异常组72例在10次语词记忆测验中通过的总例数只有43例，占59.7%，前6次通过的比例只有25%；两组之间的差异非常显著（P〈0.001）。P300异常组回忆总数、保持数、长时再现数及恒定长时再现数减少，而不恒定长时再现数、提醒总数及插入数显著增多，两组比较有显著性差异（P〈0.01）。结论P300异常的精神分裂症患者较P300正常的精神分裂症患者存在更严重的语词记忆障碍。     

2型糖尿病患者的智能障碍

目的：调查没有临床神经损害体征的2型糖尿病患者早期的高级神经功能改变，方法：分别对52例2型糖尿病患者和32名健康对照者进行了韦氏智力量表的相似、数字广度、数字符号、木块图等4项分测验测定，采用二合一(相似、木块图)的方法计算简式智商，同时进行事件相关电位检查，结果：糖尿病患者组的相似、木块图分测验成绩和简式智商明显较健康对照组低下，ERP检查发现病人组N2、P3潜伏期较对照组明显延长，结论：2型糖尿病可导致高级神经功能损害。并且这种损害可能要早于周围神经损害。     

Repetitive magnetic stimulation of cortical motor areas in Parkinson's disease: implications for the pathophysiology of cortical function.

We investigated the neurophysiological and clinical effects of repetitive magnetic stimulation (rTMS) delivered to the cortical motor areas in healthy subjects and patients with Parkinson's disease. rTMS was delivered with a high speed magnetic stimulator (Cadwell, Kennewick, WA) through a figure-eight coil centred on the primary motor area at a stimulus intensity of 120% motor threshold. Trains of 10 stimuli were delivered at frequencies of 5 Hz while subjects were at rest and during a voluntary contraction of the contralateral first dorsal interosseous muscle. In normal subjects at rest, the muscle evoked responses (MEPs) to each stimulus in a train of magnetic stimuli progressively increased in size during the train. rTMS left the MEPs unchanged in patients off therapy and had a small facilitatory effect in those on therapy. In normal subjects and patients, 5-Hz rTMS trains delivered during a voluntary contraction of the target muscle left the MEP unchanged in size. MEPs were followed by a silent period that increased in duration during the course of the train. The silent period duration increased to a similar extent in patients and controls. The reduced rTMS-induced facilitation of MEPs in patients with Parkinson's disease reflects a decreased facilitation of the excitatory cells in the cortical motor areas.     

尺骨鹰嘴骨折皮质骨加压螺钉固定的实验研究及临床应用

比较尺骨鹰嘴骨折加压螺钉与常用的4种内固定的强度,为临床选择内固定方法提供实验依据。用22具新鲜尸体肘关节做成横型、斜形和粉碎形鹰嘴骨折模型。用5种内固定后置于MD—10E万能电子力学试验机上,测定骨折处的位移与压力的关系;结果:钢丝内固定强度最小,钩钢板最大。髓内加压螺钉固定欠可靠。横形骨折皮质骨加压螺钉与张力带钢丝比较,统计学上无显著差异(P〉0.05),斜形骨折皮质骨加压螺丝钉强于张力带钢丝(P〈0.01)。粉碎形骨折使用钩钢板尤佳(P〈0.01)。临床应用24例中,22例平均随访14个月。骨折全部愈合,优良率达90.91％;认为皮质骨加压螺丝钉治疗横、斜形尺骨鹰嘴骨折,创伤小,操作简便,固定确切,是一种安全可靠的方法。