视神经脊髓炎AQP-4抗体与磁共振病灶及诱发电位的关系研究

目的研究视神经脊髓炎患者血清水通道蛋白抗体与头、脊髓磁共振病灶及诱发电位的关系。方法选取确诊的视神经脊髓炎患者56例,回顾性分析其血清水通道蛋白抗体、头及脊髓磁共振病灶、诱发电位的特点,分为AQP-4抗体阳性组及AQP-4抗体阴性组,分析水通道蛋白抗体与头、脊髓磁共振病灶及诱发电位的相关性。结果 AQP-4抗体阳性组及AQP-4抗体阴性组在头、脊髓磁共振及诱发电位方面差异有统计学意义(P0.05)。结论视神经脊髓炎患者血清AQP-4抗体与头、脊髓磁共振病灶及诱发电位具有相关性。     

视神经脊髓炎诊断进展

视神经脊髓炎是主要累及视神经和脊髓的中枢神经系统自身免疫性疾病,既往被认为是多发性硬化的一种亚型.自发现NMO-IgG以来,越来越多的证据提示视神经脊髓炎为一独立疾病.脊髓MRI所显示的长节段横贯性脊髓炎是其最具特征性的影像学改变,Wingerchuk诊断标准和美国国立多发性硬化协会推荐的诊断标准为目前常用标准.随着对视神经脊髓炎认识的加深,对视神经炎、脊髓炎及其脑部表现等临床症状的鉴别诊断水平也有所提高.     

视神经脊髓炎MRI诊断

视神经脊髓炎为一种自身免疫性炎性疾病,主要累及视神经和脊髓,脑组织也可出现病灶,但其MRI表现与经典的多发性硬化有所不同.常规MRI可以发现视神经炎和脊髓炎病灶.MRI新技术中以扩散张量成像、磁共振波谱分析及磁化传递成像的研究较多.     

视神经脊髓炎MRI诊断

视神经脊髓炎为一种自身免疫性炎性疾病,主要累及视神经和脊髓,脑组织也可出现病灶,但其MRI表现与经典的多发性硬化有所不同.常规MRI可以发现视神经炎和脊髓炎病灶.MRI新技术中以扩散张量成像、磁共振波谱分析及磁化传递成像的研究较多.     

视神经脊髓炎一家系二例

例1女,56岁,于1998年出现左眼视力下降,诊断为球后视神经炎,激素治疗后好转。随后3年内两眼交替出现3次球后视神经炎,视力逐渐下降,双眼遗有指动视力。曾行视觉诱发电位检查示:双眼P100潜伏期延长。2001年反复出现左下肢麻木,后出现双下肢截瘫,大小便失禁,行颈、胸、腰椎磁共振成像(MRI)示髓内脱髓鞘病变累及脊髓全段,头颅MRI未见明显异常,诊断为视神经脊髓炎。2005年7月突然出现左眼视物不清入我院。查体:右眼视力眼前指动。左眼光感,眼底为原发性视神经萎缩改变,双上肢肌力Ⅳ级,腱反射(+++),双上肢Hoffmann征(+),双下肢肌力0级,右侧Chaddock征(±),胸5以下浅痛觉减退。给予激素、环磷酰胺、保护神经等治疗后,左眼视力改善。     

视神经脊髓炎与急性横贯性脊髓炎的临床比较

视神经脊髓炎(neuromyelitis optica，NMO)是视神经与脊髓同时或相继受累的急性或亚急性脱髓鞘疾病；急性横贯性脊髓炎(acute transverse myelitis，ATM)是一种病因不明的脊髓炎性疾病。我们就NMO与ATM的临床、实验室及影像学检查结果进行回顾性对比研究，现报道如下。     

磁刺激运动诱发电位及磁共振对脊髓炎定位诊断的对比分析

目的比较磁刺激运动诱发电位(MEP)和脊髓磁共振(MRI)检查对急性横贯性脊髓炎(ATM)和视神经脊髓炎(NMO)病人进行定位诊断的价值。方法对临床确诊为ATM 40例和25例NMO的住院患者的MEP和MRI检查结果进行分析,比较两种检查定位符合率。结果MRI显示ATM患者以胸脊髓损害为主,NMO组患者以颈胸段联合损害为主。MEP显示ATM组患者主要表现为上肢锥体束传导正常、下肢锥体束传导异常,而NMO组患者在表现为上下肢锥体束传导均异常。当病变位于颈髓时,ATM组患者定位符合率为92.8%,NMO组患者定位符合率为95.2%;当病变位于胸髓时,ATM符合率100%,NMO符合率80%。结论在ATM和NMO患者中,MEP提示的锥体束异常部位与MRI所证实的病变部位相吻合。     

视神经损伤经颅视神经管减压与视觉诱发电位的临床研究

目的探讨视神经损伤患者经颅视神经管减压治疗的临床疗效。方法回顾性分析经颅视神经管减压治疗的视神经损伤患者35例临床资料,3个月后复查视力及视觉诱发电位(VEP)检查。结果经颅神经管减压术后患者视力大部分改善;术前无光感患者术后视力恢复差;术后患者VEP的P100潜伏期延长、波幅降低,无光感患者波幅下降最明显。结论经颅神经管减压治疗有效,术前无光感患者手术效果差,术后VEP异常明显,VEP评价客观有效,与临床一致。     

视神经脊髓炎的护理体会

视神经脊髓炎（NMO）是视神经和脊髓同时或相继受累的急性或亚急性脱鞘性病变^[1]。病因和发病机制上不清楚,多认为是MS的一种亚型。黄种人则NMO具有易感性,以视神经和脊髓损害最常见。我科于2000-2008年共收治视神经脊髓炎3例,死亡1例,恢复2例,护理体会如下。     

Maturation of visual evoked potentials across adolescence

Adolescence represents the period of transition from childhood to adulthood and is characterized by significant changes in brain structure and function. We studied changes in the functional visual processing in the brain across adolescence. Visual evoked potentials (VEPs) to three types of pattern reversal checkerboard stimuli were measured in 90 adolescents (10-18 years) and 10 adults. Across adolescence, the N75 and P100 VEP peaks decreased in size while the N135 peak increased slightly in size. The latency of VEP peaks showed no reliable change across adolescence. The results suggest that even very basic visual sensory function continues to develop throughout adolescence. The results indicate significant changes in visual parvocellular and magnocellular pathways across adolescence.     

Pattern reversal visual evoked potentials in awake rats

A method for recording pattern reversal evoked potentials (PREPs) from awake restrained rats has been developed. The procedure of Onofrj et al. [26] was modified to eliminate the need for anesthetic, thereby avoiding possible interactions of the anesthetic with other manipulations of interest. Rats were restrained in a harness and placed in front of a pattern generating TV screen displaying a black and white alternating square wave grating. Using various stimulation and recording parameters, normative data are presented from 141 adult male Long-Evans hooded and 11 adult male Sprague-Dawley albino rats. Reliable waveforms were recorded with five identifiable peaks. The labels and mean latencies of these peaks in hooded rats were: N1, 47.3 msec; P1, 65.7 msec; N2, 83.3 msec; P2, 94.4 msec: and N3, 129.8 msec. Spatial acuity functions generated with PREPs gave acuity estimates which corresponded closely to values determined behaviorally for hooded and albino rats [4,11].     

Objective visual field evaluation using multifocal visual evoked potentials in patients with intracranial disease complicated by mental disorders

OBJECTIVES: We investigated whether visual field defects can be objectively evaluated using multifocal visual evoked potentials (mfVEPs) in patients with intracranial disease complicated by mental disorders. PATIENTS AND METHODS: First, to determine the normal pattern of mfVEPs, recordings were performed using a VERIS Junior Science recording apparatus (Mayo, Aichi, Japan) in 40 healthy subjects. Responses from 8 sites in each subject were divided into 4 quadrants (superior and inferior temporal quadrants and superior and inferior nasal quadrants). In each quadrant, two response waves were grouped and averaged, and the peak latency and amplitude were used for assessment. mfVEP recordings were also performed in 3 patients with intracranial disease complicated by mental disorders, in whom dynamic or static perimetry was impossible, or in whom reliable data could not be obtained, and quadrants showing abnormalities were compared with the sites of intracranial lesions observed by imaging techniques. RESULTS: In the 40 normal subjects, no significant differences were observed in the peak latency among the 4 quadrants, but the amplitude was significantly higher in the inferior than in the superior semi-field. mfVEPs in the 3 patients revealed abnormal waves, which corresponded to the lesions observed by imaging techniques. CONCLUSION: The objective evaluation of visual field defects using mfVEPs may be useful in patients with intracranial disease complicated by mental disorders, in whom kinetic/static perimetry as a subjective examination is difficult.     

Pattern shift visual evoked potentials in Charcot-Narie-Tooth disease,HMSN type I

Summary Pattern shift visual evoked potentials were investigated in 9 subjects with Charcot-Marie-Tooth disease, who were classified as HMSN I on clinical, genetic and electromyographic criteria. The latency of the second positive peak was increased in 7 eyes of 5 subjects. These results suggest that patients with HMSN I the optic nerves may be affected more frequently than suspected on clinical examinations.

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Zusammenfassung Visuelle, durch Schachbrettmusterumkehr evozierte Potentiale wurden bei 9 Patienten mit einer neuralen Muskelatrophie untersucht. Die Patienten wurden entsprechend genetischer, klinischer und elektromyographischer Befunde als Typ HMSN I klassifiziert. Die Latenzen des zweiten positiven Gipfels der visuell evozierten Potentiale waren in 7 Augen von 5 Patienten eindeutig pathologisch verlängert. Aufgrund dieser Ergebnisse ist es wahrscheinlich, daß der N. opticus in einem höheren Prozentsatz bei Patienten mit einer neuralen Muskelatrophie, Typ HMSN I, betroffen ist als klinisch vermutet werden kann.

     

The significance of luminance on visual evoked potentials in diagnosis of MS

Summary In view of the fact that with psychophysical methods monocular luminance changes may increase the detection rate of pathological interocularlatency differences in MS patients, we studied the influence of stimulus luminance on the detection rate of MS using checkerboard visual evoked potentials. Decrements of stimulus luminance covering a range of three log units were unable to increase the detection rate of VEP. Regression coefficients of the luminance-latency functions did not differ in MS patients and normals. Contrary to the hypothesis tested, the diagnostic significance of VEP decreases with decreasing stimulus intensity.

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Zusammenfassung Nachdem psychophysische Experimente nahelegen, daß schon nach geringen Leuchtdichteänderungen die interokulären Latenzdifferenzen bei MS-Patienten beträchtlich zunehmen, untersuchten wir den Einfluß von Leuchtdichteänderungen auf die diagnostische Trefferrate der VEP bei der Multiplen Sklerose. Über einen Bereich von drei logarithmischen Einheiten brachten Leuchtdichteänderungen keine Zunahme der diagnostischen Ausbeute. Auch die Regressionskoeffizienten der Funktion VEP-Latenz gegen Leuchtdichte unterschieden sich bei MS-Kranken nicht von denen bei Gesunden. Da bei abnehmender Leuchtdichte die Trefferquote der VEP sogar deutlich abnimmt, muß diese Variable in der Klinik beachtet werden.

     

Potentiation instead of habituation characterizes visual evoked potentials in migraine patients between attacks

We have studied habituation of the pattern-reversal visual evoked potential (VEP) in healthy volunteers (n = 16) and in patients suffering from migraine without (n = 27) or with aura (n = 9). Five blocks of 50 responses at a stimulation rate of 3.1 Hz were sequentially averaged and analyzed separately for latencies, peak-to-peak amplitudes of N1-P1 and P1-N2, and the area under the N2 component Latencies of N1, P1, or N2 components were not significantly different between the sequential trial blocks, or between groups. Mean amplitudes of N1-P1 and P1-N2 in the first and subsequent blocks of SO responses were not statistically different among groups. In healthy subjects, there was a decrement of N1-P1 and P1-N2 amplitudes and N2 area on successive averagings. This habituation was maximal in the third and fourth blocks, but tended to disappear in the fifth block. In marked contrast to healthy subjects, migraine patients were characterized by a transient amplitude increment (i.e. potentiation) of VEP components which reached its maximum in the second to fourth blocks. Amplitude changes in sequential blocks were not dependent on attention and differed significantly between healthy subjects and migraineurs, but not between migraine with and without aura. Taken together with previous studies showing deficient habituation of contingent negative variation in migraine, these results indicate a dysfunction of central information processing which might have behavioral and pathogenic correlates.     

Changes in subcortical visual and auditory evoked potentials following amygdaloid kindling in cats

In this study we dealt with the changes in visual and auditory evoked potentials following kindling, to reveal the distant effects of epileptic activity. The experiments were performed using cats. Visual and auditory evoked potentials were obtained initially. Daily stimulation of 60 Hz (rectangular wave, 1 ms in duration, 500 microA in peak current, 2-s train) was given to the right amygdala, for kindling. After the completion of kindling, evoked responses were recorded again. In the auditory system the changes of responses in the cortex, medial geniculate nucleus, and cochlear nucleus were distinguished. The changes of potentials in the subcortex were larger than those at the cortical level. For visual evoked potentials there was a discrepancy between stimulation with light and electrical stimulation of the optic chiasm. There was no significant change in amplitude of visual evoked potentials by flash. In the case of optic chiasm stimulation, an enlargement of evoked responses was obtained. These results indicate modality-specific change of the auditory system and widespread subcortical change. These results might be caused by some vulnerability of the auditory system in the case of amygdaloid kindling, as a result of the epileptogenic process.     

Study of visual evoked potentials in the assessment of the central optic pathways in leprosy patients

Abstract. We evaluated the possible involvement of central optic pathways (COP) in leprosy patients with visual evoked potentials, an easy, sensitive and reliable noninvasive method for evaluation of COP. In 37 patients with lepromatous leprosy and in 37 age-matched controls, we measured reversal pattern visual evoked potentials (RP-VEP) and nerve conduction parameters. The mean latency value of positive peak P100 in leprosy patients was significantly delayed compared to that of controls (patients, 108.02±9.61 ms in left eye and 108.23±8.51 ms in right eye; controls, 96.22±4.20 ms in left eye and 95.75±4.03 ms in right eye; p<0.05). Abnormally delayed P100 latency was recorded in 5 of 37 leprosy patients (13.5%). The mean amplitude of P100 latency in leprosy patients was smaller than that of controls (patients, 8.7±5.6 µV in left eye and 9.5±4.8 µV in right eye; controls, 10.7±4.6 µV in left eye and 10.5±5.1 µV in right eye), but this difference was not significant. No correlation was observed between abnormalities of RP-VEP and sensorimotor nerve conduction parameters. This study suggests that involvement of COP may develop in patients with lepromatous leprosy. RP-VEP measurement, which can be easily and rapidly performed in an EMG laboratory using standard equipment, can show these alterations.     

Intraoperative subcortico-cortical evoked potentials of the visual pathway under general anesthesia

ObjectiveTo assess whether intraoperative subcortical mapping of the visual pathways during brain surgeries was feasible.MethodsSubcortico-cortical evoked potentials (SCEPs: 30 stimulations/site, biphasic single pulse, 1.3 Hz, 0.2 ms/phase, maximum 10 mA; bipolar probe) were measured in 12 patients for stimulation of the optic radiation, Meyer’s loop or optic nerve. Recorded sites were bilateral central, parietal, parieto-occipital, occipital (subdermal scalp electrodes, 5–4000 Hz). The minimum distances from the stimulation locations, i.e. the closest border of the resection cavity to the diffusion tensor imaging based visual pathways, were evaluated postoperatively (smallest distance across coronal, sagittal and axial planes).ResultsStimulation elicited SCEPs when the visual tracts were close (≤4.5 mm). The responses consisted of a short (P1, 3.0–5.6 ms; 8/8 patients) and of a middle (P2, 15–21.6 ms; 3/8 patients) latency waveforms. In agreement with the neuroanatomy, ipsilateral occipital responses were obtained for temporal or parietal stimulations, and bi-occipital responses for optic nerve stimulations.ConclusionsFor the first time to our knowledge, intraoperative SCEPs were observed for stimulations of the optic radiation and of Meyer’s loop. Short latency responses were found in agreement with fast conduction of the visual pathway’s connecting myelinated fibers.SignificanceThe mapping of the visual pathways was found feasible for neurosurgeries under general anesthesia.     

Effect of noradrenergic denervation on task-related visual evoked potentials in rats

The present study examines whether destruction of the noradrenergic innervation of the forebrain interferes with the processing of sensory information in a manner that results in impaired selective attention. Electro-cortical responses to task-relevant and irrelevant stimuli were found to be sensitive indicators of the rat's attention to the stimuli. The amplitude of the response to the task-relevant stimulus increased as the rat's performance improved. The response to irrelevant flashes of light depended on the predictability of the flashes and on the rat's level of arousal. Noradrenergic denervation (with the selective neurotoxin DSP4) did not affect either the behavioural response to a visual stimulus which the rat had been trained to respond to for a food reward, or the late positive potential evoked by this stimulus. Neither did it affect the response to continuous (temporally predictable) flashes of light that were irrelevant to the task. Although the response to unpredictable flashes was also largely unaffected, we did find an additional late component in this response after DSP4 treatment. These results show that the noradrenergic innervation of the occipital cortex does not always regulate the extent to which visual stimuli are processed, but that noradrenergic neurotransmission may be activated in order to diminish excessive processing of unexpected stimuli.