Brainstem evaluation in children with primary nocturnal enuresis

We investigated the brainstem integrity in children with primary nocturnal enuresis (PNE) using auditory brainstem responses (ABR), blink reflex and exteroceptive suppression of the masseter muscle. We examined 23 children with PNE (16 male, 7 female; mean age: 10.4 years) and 19 control subjects (11 male, 8 female; mean age: 11.8 years). ABR parameters such as wave latencies, amplitudes and interpeak latencies and blink reflex parameters such as R1 and R2 amplitude and latencies were not significantly different between the 2 groups. Although S2 parameters of the exteroceptive suppression of the masseter muscle were easily and completely obtained from the control subjects, in the PNE group S2 onset latency and duration were not recorded in 26% of the study children (n = 6) (P = 0.01). S2 duration time was significantly lowered in the enuretic group (left side: P = 0.001 and right side: P = 0.003). S2 duration time changes in the enuretic group supports a possible brainstem dysfunction in children with PNE.     

Blink reflex in hyperthyroidism

Although there are studies regarding the effects of thyroid hormones on some neurologic reflexes, literature lacks knowledge of the effects of thyroid hormones on blink reflex circuits. To understand the behaviour of excess thyroid hormone on this circuit that involves synapses in brainstem, we studied electrically elicited blink reflexes of 7 patients with hyperthyroidism, 8 patients with hyperthyroidism who were under therapy and 14 volunteers as control by electroneuromyograph. Mean values of the latencies and amplitudes of the R1 and R2 responses were not statistically different between groups, while the duration of R2 response and controlateral R2 response were found shorter in patients with hyperthyroidism comparing to the patients under therapy and controls. We have thought that these findings might reflect the inhibitor effect of the excess thyroid hormone on polysynaptic reflex arc of the blink response.     

兔水中毒时体感诱发电位

应用水负荷附加抗利尿激素,复制水中毒模型。当水负荷增加兔体重10%后,体感诱发电位(SEP)成份P7、N9、P12和N15峰值潜伏期随体重增加而逐渐延长。体重增加10%及15%时,P12和N15成份振幅均增大,但当增加体重15%以上时,两成份振幅减小或消失。水负荷后SEP峰间潜伏期的延长以P12—N15最显著。各种程度水负荷时,P7和N9的振幅均无显著变化。结果说明,水负荷增加体重10%后,可使神经元的传导发生延缓及皮层神经元兴奋性改变;不同程度的水负荷对神经元兴奋性的影响并不相同,此外水负荷对大脑皮层功能的影响较低位脑干严重。     

Reconsiderations about the abnormalities of somatosensory evoked potentials in motor neuron disease

The frequency of involvement of sensory pathways in motor neuron disease (MND) remains the matter of controversy. For this reason the purpose of the present work was to test how often sensory system involvement might be detected by somatosensory evoked potentials (SEP) studies and then to verify the presence of alteration of the sensory conduction and to detect the frequency of abnormalities of somatosensory peripheral, spinal, subcortical and cortical potentials in MND. SEP were tested after median nerve stimulation at the wrist, recorded from Erb's point, Ce2, Ce7 and scalp. Pearson's correlation coefficients test and Wilcoxon rank-sum test were used for statistical analysis. 74 patients (22 women and 52 men) were examined. Mean age of patients was 54.07 +/- 11.24 years; mean duration of the disease -19.25 +/- 15.87 months. SEP were abnormal in 39 of 74 patients (about 53%) whereas the sensory NCV in median nerve was abnormal in 14 of 74 patients (19%). The most frequent pattern of abnormalities consisted of the absence or delay of cortical responses. The mean values of SEP latencies (N9, N11, N13, N20 and P25) were significantly increased in MND patients (p < 0.05) as compared with controls. The N9 and N11 latencies correlated with the duration of the disease. The results of our study (concerning a large group of MND patients) suggest that the involvement of sensory pathways is not rare in MND.     

Cervical Vestibular Evoked Myogenic Potentials (cVEMPs) Evoked by Air-Conducted Stimuli in Patients with Functional Neck Dissection

Objective

Cervical vestibular-evoked myogenic potentials (cVEMPs) are short-latency vestibulocollic reflexes. The damage on any point of the vestibulocollic reflex pathway could affect the cVEMPs. Whether neck dissection has an effect on the sacculocollic pathway, and consequently on cVEMPs, remains unexplored. The aim of this study was to evaluate the cVEMP findings in patients with functional neck dissection without vestibular symptoms.

Narcolepsy-cataplexy: deficient prepulse inhibition of blink reflex suggests pedunculopontine involvement

Hypocretin (orexin) deficiency plays a major role in the pathophysiology of narcolepsy–cataplexy. In animal models, hypocretinergic projections to the pedunculopontine nucleus are directly involved in muscle tone regulation mediating muscle atonia – a hallmark of cataplexy. We hypothesized that pedunculopontine nucleus function, tested with prepulse inhibition of the blink reflex, is altered in human narcolepsy–cataplexy. Twenty patients with narcolepsy–cataplexy and 20 healthy controls underwent a neurophysiological study of pedunculopontine nucleus function. Blink reflex, prepulse inhibition of the blink reflex and blink reflex excitability recovery were measured. Blink reflex characteristics (R1 latency and amplitude, and R2 and R2c latency and area under the curve) did not differ between patients and controls (P > 0.05). Prepulse stimulation significantly increased R2 and R2c latencies and reduced R2 and R2c areas in patients and controls. However, the R2 and R2c area suppression was significantly less in patients than in controls (to 69.8 ± 14.4 and 74.9 ± 12.6%, respectively, versus 34.5 ± 28.6 and 43.3 ± 29.5%, respectively; each P < 0.001). Blink reflex excitability recovery, as measured by paired‐pulse stimulation, which is not mediated via the pedunculopontine nucleus, did not differ between patients and controls (P > 0.05). Our data showed that prepulse inhibition is reduced in narcolepsy–cataplexy, whereas unconditioned blink reflex and its excitability recovery are normal. Because the pedunculopontine nucleus is important for prepulse inhibition, these results suggest its functional involvement in narcolepsy–cataplexy.     

痉挛性斜颈体感诱发电位的研究

目的：探讨痉挛性斜颈患者大脑皮层功能的变化。方法：对30例痉挛性斜颈患者刺激正中神经后体感诱发电位（SEP）的P22、N30波潜伏期及P22、N30波幅进行比较分析,30例正常对照组仅在颈部主动向右侧扭转时对双侧P22、N30波幅进行比较分析。结果：病例组SEPP22、N30潜伏期正常,双侧比较差异无统计学意义,头部扭转方向的对侧大脑半球前中央区的P22-N30波幅比明显高于对侧,差异有统计学意义。正常对照组前中央区记录的双侧P22N30波幅比较差异无统计学意义。结论：SEP P22、N30潜伏期正常提示传导通路结构完整,头部扭转方向的对侧大脑半球前中央区的P22-N30波幅比明显高于对侧,提示患者对侧大脑皮层前中央区电活动存在异常的兴奋及抑制,即抑制性减弱,兴奋性增高,N30记录的是刺激正中神经SEP中长潜伏成分,可能来源于运动辅助区,进一步提示患者存在感觉一运动整合功能异常。     

肝硬化失代偿期病人体感诱发电位观察

目的 :探讨肝硬化失代偿期病人的神经功能状态。方法 :对 30例肝硬化失代偿期病人进行体感诱发电位 (SEP)检查 ,刺激部位均为右腕正中神经。结果 :肝硬化失代偿期病人的SEP有着不同程度的改变 ,其中P15、N2 0 、P2 5、N3 5的潜伏期延长和N13 -P15的波间期延长分别占本组异常数的 85 %、40 %、35 %、2 5 %和 2 0 %。这些值与正常人组相比较 ,其两组间差异均有极显著性意义 (P <0 0 1)。结论 :SEP可为研究亚临床肝性脑病提供电生理学的客观依据。     

Auditory evoked potentials as possible predictors of outcome in schizophrenic outpatients

As part of a follow-up study on long-term neuroleptic treatment, 36 schizophrenic out-patients under neuroleptic treatment were studied in an 'auditory oddball' event-related potential paradigm after a 3-month stabilization phase following clinical discharge. In the first cross-sectional analysis, we evaluated the influences of age and gender and tried to find auditory evoked potential (AEP) variables, which might be promising as potential predictors of the course of illness. Compared with healthy age-matched controls, the patients showed smaller N1/P3-amplitudes. Males and females showed only minor AEP-differences, the amplitude N1/P2 being slightly higher in females. Age correlated positively with the latency P3 and negatively with the latency P2R. The interpeak latency P3-P2R showed the highest correlation with age. Test/re-test reliability was measured and variables with r less than 0.60 were rejected. The amplitudes N1/P2 and N1/P3 showed the highest test/re-test correlations. The more severely disturbed patients (global assessment scale [GAS]-score less than 65) had shorter interpeak latencies P2F-N1F than the less disturbed patients (GAS greater than or equal to 65). Patients with a high rate of relapse tended to have shorter interpeak latencies P2F-N1F than patients with low rates of relapse. Our results indicate that the interpeak latency P2F-N1F has an acceptable test/re-test reliability (C3: r = 0.72; C4: r = 0.80) and is related to clinical variables characterizing the course and outcome of illness. This leads to the hypothesis that a short interpeak latency, P2F-N1F, might be a predictor of poor prognosis.     

改良的下肢SLSEP检测方法对糖尿病近端神经病的诊断意义

目的：探讨改良的短潜伏期体感诱发电位（SLSEP）（改变记录点）的检测方法对糖尿病性近端神经病的诊断意义。方法：排除脑卒中、腰颈椎病及其它疾病引起的神经肌肉疾病,肌电图检查排除有神经病变体征同时常规神经传导检测异常的糖尿病（DM）患者,将符合标准的61例2型DM患者分为3组：有神经病体征而常规神经传导检测正常（Ⅰ组）20例,无神经病体征且常规神经传导检测正常（Ⅱ组）21例和无神经病体征而常规神经传导检测异常（Ⅲ组）20例,与30例正常人均行改良的SLSEP测定。结果：改良的胫神经SLSEP反映下肢感觉神经近端功能的参数总异常率以DM有神经病变症状肢体亚组（Ⅰ组）（n=27）所占的比例最高（85％,23／27）,SLSEP反映神经近端功能的N13、N24峰的感觉神经传导速度（SCV）和N13N24、N9-N24峰间SCV,与对照组比较差异均有显著意义（P〈0．01）;DMⅡ组虽然无神经病变体征并且神经传导测定无异常,但与对照组比较,N13-N24峰间SCV异常肢体率却有显著差异（P〈0．01）。DMⅢ组SLSEP各参数异常率普遍较高（20％～72．5％）,但以反映神经远端功能的N9峰SCV异常率最高。结论：改良的SLSEP检测是对常规SCV检测的一种补充,可以提供感觉纤维近端信息,对有周围神经损害症状而常规SCV测定正常的DM患者其诊断意义尤为显著。SLSEP还有利于发现DM患者亚临床症状。     

Nerve conduction study, electromyography and somatosensory evoked potentials in non-Friedreich early onset cerebellar ataxia. A comparative study with Friedreich's ataxia and late onset cerebellar ataxia.

Electrophysiological findings in 14 patients with non-Friedreich early onset cerebellar ataxia are reported. Nerve conduction studies showed reduction of sensory action potential amplitudes in 7 cases associated in 3 with a decrease of sensory conduction velocities. Six subjects also exhibited a chronic neurogenic pattern to standard needle electromyography. Motor conduction velocities were normal in all cases; only two cases showed an increase in distal motor latencies. Short-latency somatosensory evoked potentials following median nerve stimulation revealed a prolonged central conduction time (N13-N20 interpeak latency) in 7 cases, compatible with supraspinal damage of the somatosensory pathways. These electrophysiological data are compared with those obtained in two reference groups of patients, respectively affected by Friedreich's ataxia and olivo-ponto-cerebellar atrophy.     

甲状腺机能障碍患者的体感诱发电位

应用电子计算机迭加平均技术,记录了24名甲状腺机能亢进症(甲亢)、4名甲状腺机能减退症(甲减)患者和32名正常受试者的正中神经体感诱发电位(SEPs)。在24名甲亢患者中F_(?)峰值潜伏期延长者12例,N_(13)-N_(20)传导时间缩短者2例;4例甲减患者中,Ep峰值潜伏期延长者3例,N_(20)峰值潜伏期延长者1例,N_(13)-N_(20)传导时间延长者1例。结果表明,甲状腺机能异常者不仅可出现外周神经传导功能障碍,而且也可能出现中枢传导功能的异常。     

High frequency vibration induced gating of subcortical and cortical median nerve somatosensory evoked potentials: different effects on the cervical N13 and on the P13 and P14 far-field SEP components.

Subcortical and cortical somatosensory evoked potentials (SEP) to median nerve stimulation were recorded before, during and after high frequency (270 Hz) vibration of the fingers 1-3 in 8 healthy subjects. A marked decrease of the amplitude of all potentials was observed. The attenuation of the sensory nerve action potential (SNAP) of the median nerve and the attenuation of SEP components N9, N11 and N13 showed no differences, while the attenuation of the subcortical P14 component was significantly higher. This is in accordance with a generator of the cervical N13 in the interneurons beside the lemniscal pathway. The cortical N20 (post-rolandic) was significantly more decreased in amplitude than P14 while P22 (pre-rolandic) remained reduced in amplitude like P14. An increased latency of the far-field subcortical P14 was observed, while P13 recorded in the same montage remained unchanged in latency. These findings suggest different generators of these peaks. A generator of P14 above the nucleus cuneatus is confirmed. A presynaptic generator of P13 is suspected.     

Acoustic startle response in patients with orthostatic tremor

Background and aim

Orthostatic tremor is a high frequency tremor predominantly on calf muscles during standing. Brainstem is the most probable generator in the pathogenesis since it comprises bilaterally projecting centers regulating stance or tone. We aimed to investigate the functional role of brainstem through the evaluation of acoustic startle response in primary orthostatic tremor patients.

Patients and method

We included 7 (2 males) consecutive patients and 13 (5 males) healthy volunteers. Diagnosis was confirmed by polymyographic surface electromyography. All subjects underwent acoustic startle response and blink reflex investigations.

Results

Presence rate (71.4% vs. 100%, p = 0.042) and response rate (27.5% vs. 40.5%, p = 0.047) of total acoustic startle response were lower in patient group. Similarly, probability over orbicularis oculi was lower among patients (p = 0.003). However, blink reflex was observed in all patients and healthy volunteers and latencies of startle and blink reflexes were similar between groups.

Conclusions

In our patient group, normal response rate and latencies of R1 and R2 show structural integrity of at least blink reflex circuit at brainstem. On the other hand, suppressed response rates probably reflect decreased excitability of auditory startle reflex pathway.     

Methods for Studying the Blink Reflex and Its Normative Parameters

Investigation of the blink reflex represents a contemporary and highly informative method in electroneurophysiological diagnosis. Contradictory data from clinical studies of the blink reflex show the relevance of the problem and dictate the need for forming universal approaches to methods of studying and interpreting the results obtained. The characteristics of the formation of the reflex electromyographic (EMG) components of the blink reflex of the orbicularis oculi muscle were studied during electrical stimulation of the supraorbital nerve in 31 healthy subjects. The latencies of the R1 and R2 components, the amplitude of the R1 component, and the area of the total power spectrum of the EMG discharges constituting the R2 component, the duration of the R2 component, and the latency of the R3 component were studied during the blink reflex.     

Somatosensory evoked potentials from median nerve; normative data

The somatosensory evoked potentials from median nerve were studied in a group of 127 normal adults aged from 19 to 79. The latencies of elbow, Erb's, cervical N11 and N13 as well as cortical N20 and P25 potentials were analyzed as a function of height and age. Two central conduction times, N20-N11 and N20-N13, were equally studied. The corresponding regression formulae were calculated and can be used to predict normative values of these parameters over a wide range of height and age. Standard error estimates are given for all parameters.     

不同年龄抑郁症患者瞬目反射的研究

目的:探讨抑郁症与瞬目反射(BR)的关系。方法:对90例抑郁症(青年和老年各45例)患者及60例正常对照组(青年和老年各30例)进行BR检测。结果:与青年对照组和老年对照组比较,青年抑郁症患者和老年抑郁症患者BR的R2、R2′潜伏期分别显著延长(P<0.001),老年抑郁症患者的波幅与老年对照组、青年抑郁症患者的波幅相比显著升高,差异存在极显著意义(P<0.001)。结论:抑郁症患者存在BR的异常,提示抑郁症患者可能存在脑干功能障碍。     

Somatosensory evoked potentials in X-linked recessive bulbospinal neuronopathy: a case demonstration.

Clinicopathological findings in X-linked recessive bulbospinal neuronopathy were characterized by loss of myelinated fibers in the fasciculus gracilis and depletion of neurons in the ventral horn throughout the same segments. Clinical profile of this rare motor neuron disease include sign and symptom of lower motor neuron involving bulbar and spinal level with minimal or no sensory deficit. Previous electrodiagnostic findings consist of electrophysiological evidence of anterior horn cell disease and decreased or absent sensory action potentials in the peripheral nerve. The role of somatosensory evoked potential which can uncover the involvement of posterior column has never been probed. We report a 22-year-old man who had a clinical syndrome of X-linked bulbospinal neuronopathy. The peripheral electrodiagnostic studies supported the evidence of prolonged anterior horn cell disease and decreased sensory response. The median SEPs revealed delayed N11-N13 and N13-N20 interpeak latencies representing demyelination in fasciculus gracilis of upper cervical cord. Therefore, the median SEPs, an uninvasive procedure, can be used as a supportive method to identify sensory neuronopathy with posterior column lesion in this syndrome, especially when the patient has no obvious sensory and endocrine symptom.     

Event related potentials in hypothyroidism

Central nervous system (CNS) dysfunction is an important consequence of thyroid hormone deficiency Several studies using objective behavioral measures reported that cognition is impaired in patients with hypothyroidism. The aim of the present study is to evaluate objectively the functional changes in the nervous system and possible cognitive effects of hypothyroidism by using event related potentials (ERP) in order to determine the frequencies of these changes in patients with hypothyroidism. Forty-two patients (3 males, 39 females) (mean age: 40 +/- 11) with newly diagnosed primary hypothyroidism were included in the study. In all patients the cause of hypothyroidism were chronic autoimmune thyroiditis. None of them had received thyroid hormone as a replacement therapy. In hypothyroid group both N2 and P300 latencies from FZ, CZ, PZ electrode positions were prolonged relative to controls and the differences were statistically significant; respectively (N200: P < 0.003, 0.003, 0.002--P300: P < 0.008, 0.02, 0.001) N100 and P200latencies from FZ, CZ, PZ electrode positions did not differed significantly from those of normal controls; respectively. (p < 0.140, 0.195, 0.153--p < 0.400, 0.185, 0.766) Latency and amplitudes of P300 did not correlated with FT3, FT4 or neither with TSH values in the patient group. We believe like other's that with the aid of this technique we are able to detect early effect on central information processing compatible with a reduction of processing resources and increased effort necessary for a given task in hypothyroid individuals.     

Corneal reflex and blink reflex changes in thalamic hemorrhage

We studied the corneal reflex (CR) with air-puff and direct touch by using a standardized method in patients with thalamic hemorrhage (TH) (n: 15) and in normal control subjects (n: 21). The conventional blink reflex (BR) was also studied. In the TH group: 1--When the cornea on the clinically nonaffected side was stimulated the corneal reflex responses were elicited bilaterally, with normal latency on the clinically normal side and delayed on the affected side. 2--When the cornea on the clinically affected side was stimulated, the corneal responses on both sides were either abnormal or could not be elicited. 3--The ipsilateral R1 and R2 responses recorded by stimulation of the supraorbital nerve on the clinically affected side were abnormal where the contralateral R2 responses were in the normal range. In the normal control and TH groups: 1--No statistical difference could be detected between the responses elicited by air-puff or direct touch to cornea (p > 0.05). 2--CR responses were statistically different from the R2 response of the BR (p < 0.005).