Improvement of Decreased Critical Flicker Frequency (CFF) in Headache Patients With Drug Abuse After Successful Withdrawal

A considerable proportion of headache patients fulfill the criteria of "drug abuse" (definition according to the International Headache Society [IHS] criteria). These patients exhibit markedly reduced vigilance and continuous performance, as shown by the results of critical flicker frequency (CFF) analysis.
The present study deals with the question whether this impairment of vigilance and continuous performance is reversible. Forty-eight headache patients with drug abuse were investigated three times by means of CFF analysis: immediately before (A), immediately after (B), and 3 weeks after having finished (C) inpatient drug withdrawal.
Immediately after withdrawal, a significant decrease of headache intensity was observed. The CFF values, however, remained unchanged at a depressed level, probably due to withdrawal medication and the initial sedative side effects of thymoleptic agents (given as prophylaxis).
Three weeks after withdrawal, however, the CFF values were significantly improved, and were now within a range not far from the normal values known from a healthy general population. Thus, even after many years of drug abuse, headache patients have a good chance to improve their vigilance and continuous performance and to reach normal or close to normal levels.     

高频超声检测颈动脉内膜-中层厚度及外周血管内皮功能评价动脉粥样硬化

目的 探讨高频超声检测颈动脉内膜-中层厚度与肱动脉内皮依赖性舒张功能在动脉粥样硬化中的诊断价值.方法 冠状动脉造影的老年患者69例及青年志愿者20例,分别行颈动脉超声检查,同时采用充气加压法测定肱动脉血流介导的内径扩张值,超声测值与冠脉造影结果对照分析.结果 ①颈动脉内膜-中层厚度值随粥样硬化斑块的增多、冠脉狭窄程度的加重而增高;②动脉粥样硬化患者在内膜-中层厚度值增高之前即可出现内皮功能损伤,肱动脉内径扩张值降低早于内膜-中层厚度值增高之前出现,内径扩张值随冠脉狭窄程度加重而下降.结论 高频超声检测颈动脉内膜-中层厚度、内径扩张值诊断早期动脉粥样硬化敏感性高,并且有助于对冠脉狭窄程度作出判断.     

Recognition performance and perceived quality of video enhanced for the visually impaired

Subjects with central field loss (CFL) individually selected enhancement parameters to improve visibility of static video images. The effect of enhancement on performance and on perceived quality of motion video was assessed. Performance, e.g. recognition of visual details, was assessed by having subjects answer questions regarding visual information contained in the video motion segments that were enhanced using the individually-selected parameters. Enhancement did not improve subject performance on questions about video content. This result might be due to a ceiling effect limitation of the performance assessment method. In a second procedure, subjects' continuous perceptions of quality (using an adjective-based rating scale) were made while the enhancement parameters were abruptly switched among multiple values; these included the individually-selected enhancements, as well as unenhanced, over-enhanced, and degraded segments. The results indicate that adaptive enhancement (individually-tuned using a static image) adds significantly to perceived image quality when viewing motion video. Subjects who selected stronger contrast enhancement also perceived the enhancement to provide a larger benefit in image quality.     

MRI的选购定位

对MRI若干主要参数进行总结,结合实际应用体会,对我院MRI设备选购进行讨论,以期对MRI设备的选购定位提供参考.     

Causality Between the Amplitude and Frequency of Cardiac Oscillations

Using an information-theoretic approach, causality between the systolic amplitude in blood pressure and the frequency of the heart beat was analyzed. Blood pressure and ECG were noninvasively recorded in young, healthy subjects. Three successive measurements were performed: during spontaneous breathing and during paced respiration—at frequencies both higher and lower than that of spontaneous respiration. We demonstrate that the amplitude and frequency of the cardiac rhythm are synchronized for most of the time. The synchronization is stronger during paced respiration at a frequency lower than that of spontaneous breathing. Episodes where the cardiac frequency was driven by the systolic pressure were also detected during slow, paced respiration.     

Spatial frequency content of the Cardiff and related acuity tests

In the Cardiff acuity test, simple pictures on an otherwise neutral grey card are defined by borders consisting of a relatively broad white band flanked by black bands each half the width of the white band. Higher levels of acuity correspond to the ability to detect figures defined by narrower borders, the figure size remaining constant. It is sometimes implied that the acuity limit corresponding to each card can be equated with different levels of grating resolution, the total width of the border corresponding to the overall grating period. It is shown that although the spatial frequency spectra of the Cardiff figures, like those of other vanishing optotypes, lack very low-frequency components, they have a complex two-dimensional form. The figures have wide spatial bandwidth and no well-defined discrete frequency components. As a result, the relationship between measured Cardiff and grating acuity will vary somewhat, depending upon the particular optical, neural or other deficits of the individual being tested.     

Heart rate response to breathing: dependency upon breathing pattern

Summary. Heart rate responses to stepwise and periodic changes in lung volume were studied in seven young healthy males. Stepwise inspiration and expiration both resulted in an increase in heart rate followed by a rapid decrease in heart rate. The fastest heart rate was reached in 1·6 ± 0·5 s and in 3·6 ± 1·4 s in response to inspiration and expiration, respectively (P < 0·01). The slowest heart rate was reached in 4·8± 1·0 s and in 7·6± 1·9 s in response to inspiration and expiration, respectively (P < 0·01). Following this biphasic change the heart rate returned to a steady level. The difference between the fastest and the slowest heart rates was significantly larger in response to inspiration (21·7 ± 7·3 beats per minute) than in response to expiration (12·0±7·3 beats per minute; P < 0·01). Periodic changes in lung volume were performed with frequencies from 3·0 to 12·0 respirations per minute (r.p.m.). The changes in heart rate showed a constant amplitude in the frequency range below 5·5 r.p.m. Maximal heart rate changes were found at frequencies of 5·5 to 7·0 r.p.m. Changes in heart rate decreased in a linear manner on a log-log scale in the frequency range above 7·0 r.p.m. The relation between frequency and changes in heart rate is explained by interference between the transient changes in heart rate induced both by inspiration and by expiration. It is concluded that if heart rate changes in response to periodic changes in lung volume are to be used as a measure of vagal function a number of factors have to be taken into consideration and to simplify the analysis of heart rate responses to breathing we recommend, instead, the use of the transient changes in heart rate induced by stepwise changes in lung volume.     

北京自然人群载脂蛋白E基因多态性频率分布研究

应用聚合酶链反应 限制性片段长度多态性技术 (PCR RFLP) ,以北京自然人群为基础 ,采用分层随机抽样的方法进行横断面研究 ,对 1 0 46人进行apoE基因分型 ,并分析不同特点人群apoE基因频率分布特点。结果表明 :1 )本组人群ε2、ε3、ε4基因频率分别为 9.1 %、81 .2 %和 9.7% ,男女和各年龄组间基因频率无显著差异 ;2 )与欧美国家相比 ,本组人群ε2基因频率增高 ,ε4频率减低 ,与日本人群相比也有相同趋势 ;3 )在空腹血糖受损及糖尿病人群中ε2频率明显增高 ;4)在高胆固醇血症人群中ε2频率减低、ε4基因频率增高     

Identifying the affected hemisphere by 1H-MR spectroscopy in patients with temporal lobe epilepsy and no pathological findings in high resolution MRI

Up to 30% of patients with temporal lobe epilepsy (TLE) remain without remarkable changes in MRI. In this study we investigated the role of (1)H-MR spectroscopy ((1)H-MRS) in lateralizing the affected hemisphere in the mentioned patient group. Twenty-two consecutive patients diagnosed with TLE were investigated by high resolution MRI and (1)H-MRS. We examined the incidence and diagnostic accuracy of temporal metabolite alterations determined by Linear Combination of Model Spectra (L C Model) via water reference. Metabolite values of each hemisphere of TLE patients were compared with healthy controls. Results of metabolite alterations were related to intensive video EEG focus localization. Reduction of N-acetylaspartate + N-acetylaspartyl-glutamate (tNAA) in the affected hemisphere revealed identification in six of nine patients (66%) with unilateral TLE. Group comparison revealed a significant reduction of tNAA (6.1+/-0.8*) in the involved temporal lobe compared with controls (6.67+/-0.4*, P=0.026). Choline levels were significantly increased in the affected hemisphere (1.42+/-0.17*) compared with healthy controls (1.22+/-0.17*, P=0.035). The results of our study show that (1)H-MRS is able to identify the affected hemisphere of MRI negative TLE patients and can be used as an additive tool in multimodal focus localization.     

X线录相对无喉人食管发音机理的初步探讨

本文对19名无喉人食管发音患者,利用X线电影、X线录相及录音技术,对食管发声的机理进行了图、声同步的动态观察与分析。认为食管发声须经过:科学训练;代声门形成;贮气、送气、发音三个时相过程及口腔、鼻腔、舌唇、齿等构字器官的协调配合加工而成。文中还对此项检查设备、方法、检查前准备及步骤进行了详尽论述。