Vestibular evoked myogenic potentials in multiple sclerosis patients.

OBJECTIVES: Vestibular evoked myogenic potentials (VEMPs) are saccular responses to loud acoustic stimuli and are recordable from the sterno-cleido-mastoid muscle ipsilaterally to the stimulated ear. This study aimed to investigate VEMPs in patients suffering from multiple sclerosis (MS), and to compare these findings with both clinical and instrumental data. METHODS: We recorded VEMPs from 70 MS patients, whose clinical data were retrospectively evaluated for the possible occurrence of: past and current (with respect to VEMP recording) brainstem and/or cerebellar symptoms; current brainstem and/or cerebellar signs. Sixty-five patients underwent brainstem auditory evoked potentials (BAEPs) recording; 63 of the same patients underwent saccadic eye movement recording and subjective visual vertical (SVV) evaluation. RESULTS: VEMPs were abnormal in 31%, BAEPs in 38% and SVV in 21% of the patients. Saccadic eye movements showed a possible brainstem dysfunction in 44.4% of the patients. There was no correlation between the occurrence of abnormalities and the technical means of detection. The same held true for correlations with clinical data, with the exception of the BAEPs; these proved to be more frequently abnormal in patients presenting at neurological examination with brainstem and/or cerebellar signs that were possibly related to the complaint of dizziness. CONCLUSIONS: VEMPs should be considered a useful complementary neurophysiological tool for the evaluation of brainstem dysfunction.     

Pattern visual evoked potential luminance and multiple sclerosis.

Pattern visual evoked potentials (PVEPs) were recorded from 111 patients classified as having possible, probable or definite multiple sclerosis. Patients were stimulated with a checkerboard pattern using high and low luminances in order to test the hypothesis that an attenuated pattern luminance increases the detection rate of PVEP abnormalities. With increasing certainty of diagnosis, there was a concomitant increase in the incidence of PVEP abnormalities. However, there was no evidence that stimulating with a lower luminance pattern enhanced the sensitivity of the test. The same findings were also apparent when the patient data was analyzed according to the presence or absence of a history of optic neuritis or other visual symptoms. It is concluded that, within the luminance limits used in this study, the role of varied luminance in detecting demyelinating lesions in the optic nerves using the PVEP is minimal, although there was some limited evidence that a high level of luminance may be more appropriate than a low level.     

多发性硬化的诱发电位特点

目的分析多发性硬化(multiple sclerosis,MS)模式翻转视觉诱发电位(pattern reversal evoked po-tential,PRVEP)、脑干听觉诱发电位(brainstem auditory evoked potential,BAEP)和体感诱发电位(somatosenso-ry evoked potential,SEP)等三种诱发电位(evoked potential,EP)的临床特点。方法对83例确诊MS患者进行回顾性分析,根据有无相应临床症状、病程及功能残障程度对EP进行分层研究,探讨其变化规律。结果三种EP的异常率在有临床症状组〔PRVEP、BAEP及下肢短潜伏期体感诱发电位(SLSEP)异常率分别为88.00%、66.67%、100%〕与无临床症状组(PRVEP、BAEP及下肢SLSEP异常率分别为60.61%、31.71%、79.63%)间比较均存在统计学差异(均P<0.05)。PRVEP的峰潜伏期(PL)延长及侧间峰潜伏期差值(ILD)增加的异常率之和与病程呈正相关(r=1.0,P<0.05);病程在20年以内时BAEP异常率与病程呈正相关(r=1.0,P<0.05);SLSEP下肢未引出率与病程呈正相关(r=1.0,P<0.05)。PRVEP异常率与EDSS分值呈正相关(r=1.7,P<0.01);SLSEP上肢异常率及下肢未引出率也与EDSS分值呈正相关(分别r=1.8,P<0.01;r=1.6,P<0.01)。结论三种EP的异常率与有无相应临床症状相关,且与病程及功能残障程度在一定范围内呈正相关。     

多发性硬化伴可能周围神经病变的神经传导速度观察

自1904年Denkler首次报道1例多发性硬化(MS)尸检中发现有周围神经脱髓鞘病损[1]以来,MS伴随周围神经病变越来越引起研究者的注意。近年有学者提出,自身免疫病的各种临床表现可能是由免疫调节障碍引起多个靶器官受累导致,并不一定是合并多种疾病[2],周围神经系统(peripheral nervous system,PNS)与中枢神经系统(central     

Sensitivity of laser-evoked potentials versus somatosensory evoked potentials in patients with multiple sclerosis.

OBJECTIVE: Somatosensory evoked potentials (SEPs) play a less important role in the diagnosis of multiple sclerosis (MS) than visually evoked potentials. Since standard SEPs only reflect the dorsal column function, we now investigated spinothalamic tract function in patients with MS using laser-evoked potentials (LEPs). METHODS: LEPs to thulium laser stimuli (3ms, 540 mJ, 5mm diameter) were recorded from 3 midline positions (Fz, Cz, Pz) in 20 patients with MS, and 6 patients with possible but unconfirmed MS. Peak latencies and peak-to-peak amplitude of the vertex potential negativity (N2) and positivity (P2) were evaluated and compared with normative values from 22 healthy control subjects. Median and tibial nerve SEPs were recorded with standard methods. Depending on the results of sensory testing, two skin areas (both hands, both feet, or one hand and foot of the same body side) were assessed in each patient. RESULTS: In group comparisons, LEPs in patients with MS were significantly delayed and reduced in amplitude compared with healthy subjects (P<0.001) or patients with suspected but unconfirmed MS (P<0.05). In intraindividual comparisons within the patients with MS, LEP amplitude was significantly lower (P<0.01) and latencies were significantly longer (N2: P<0.01; P2: P<0.05) for a clinically hypoalgesic skin area than an unaffected control area. On a single case basis, LEPs were abnormal in 12 (60%) and SEPs in 8 (40%) of the patients with MS; combined analysis of LEPs and SEPs raised sensitivity to 75% (15 patients). LEPs were also abnormal for 7 skin areas with clinically normal nociception and thermal sensitivity, indicating subclinical lesions. Standard SEPs detected subclinical lesions in 5 areas with normal tactile sensitivity. CONCLUSIONS: In patients with multiple sclerosis, spinothalamic tract function and LEPs were impaired more often than dorsal column function and SEPs. LEPs also detected subclinical lesions. Combined assessment of LEPs and SEPs can help to document dissemination of demyelinating CNS lesions and thus contribute to the diagnosis of multiple sclerosis.     

Lumbosacral spinal evoked potentials in patients with multiple sclerosis

Lumbosacral spinal evoked potentials were recorded percutaneously in 22 MS patients with spinal symptoms and in 24 age-matched normal volunteers. Latencies, durations, and areas of waves R and A (level S1) as well as S and P2 (level Th12) were analyzed. The most significant result observed in the MS group was a reduction of the ratio between the areas of P2 and S. The reduction was strongly correlated with intensity of spasticity, but not with other clinical features. The P2/S ratio can thus be proposed as an electrophysiologic measure of spasticity.     

Cerebral evoked potentials in multiple sclerosis

Multimodal evoked potentials were analyzed from 58 possible, 62 probable and 100 definite (total 220) multiple sclerosis (MS) patients. Visual evoked potentials (VEP) were most frequently abnormal yielding 39%, 69%, 84% in the three diagnostic groups respectively. Median nerve sensory evoked potentials (SEP) yielded abnormalities in 26%, 65%, 79% respectively. Brainstem auditory evoked responses (BAER) were abnormal in 17%, 39%, 66% respectively. We measured the combined amplitude (CA) of waves III, IV, V in the BAER of these patients as an objective measure of amplitude asymmetry. The CA was considered abnormal if it was 1SD below the lowest CA value in the control group. The CA was abnormal in 9.2% of BAER with normal central conduction time. The BAER diagnostic yield in MS patients increased 11% by using CA analysis.     

Fever and evoked potentials in multiple sclerosis

Summary The somatosensory evoked potentials (SEPs) and visual evoked potentials (VEPs) were studied in 19 patients with multiple sclerosis; 17 controls were studied during fever (38.0°–39.7°C) and 2–3 days following return to normal temperature. The latencies of components N₂₀ and P₁₁₄ were measured and specified as abnormal when their value exceeded the standard deviation of the controls by 2.5 times. The corresponding criterion for the evaluation of the amplitude of components N₂₀ and P₁₁₄ was a reduction in amplitude of more than 50%. In the controls fever did not cause significant changes in evoked potentials. On the other hand, patients with multiple sclerosis showed abnormalities in evoked potentials during fever in a greater number of recordings (26 of SEPs and 33 of VEBs) than after return to normal temperature (19 and 27 respectively). In addition, the average latency of components N₂₀ and P₁₁₄ was clearly greater in the patients during fever (N₂₀=29.5±5.2 ms and P₁₁₄=143±18.1 ms) than after return to normal temperature (N₂₀=6.6±3.5 ms and P₁₁₄=134±16 ms). The amplitude of components N₂₀ and P₁₁₄ in patients during fever was clearly smaller than after return to normal temperature. These differences were statistically significant. Finally, in two patients, a decrease was found, during fever, in the conduction velocity of the peripheral somatosensory pathway from the median nerve to the wrist at Erb's point.

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Zusammenfassung Wir studierten die somatosensorisch evozierten Potentiale (SSEP) sowie die visuell evozierten Potentiale (VEP) bei 19 Patienten mit Multipler Sklerose und 17 Kontrollpersonen. Die somatosensorisch und visuell evozierten Potentiale wurden in beiden Gruppen unter dem Einfluß von Fieber als auch zwei bis drei Tage nach dem Abklingen des Fiebers untersucht.Die Latenzzeit der Komponenten N₂₀ und P₁₁₄ wurde als pathologisch bewertet, wenn ihre Werte 2,5 Standardabweichungen über dem Mittelwert von Normalpersonen lagen.Der entsprechende Maßstab für die Bewertung der Höhe der Komponenten N₂₀ und P₁₁₄ war eine Höheminderung über 50%.Wir fanden, daß Fieber bei den Kontrollpersonen keinen wesentlichen Einfluß auf SSEP und VEP hatte. Bei den MS-Patienten haben wir wesentlich mehr Abnormitäten der SSEP und VEP während des Fiebers (26 SSEP und 33 VEP) als nach dem Abklingen des Fiebers (19 SSEP und 27 VEP).Darüber hinaus war der Mittelwert der Latenzzeit der Komponenten N₂₀ und P₁₁₄ bei den MS-Patienten während des Fiebers höher (N₂₀=29,5±5,2 ms; P₁₁₄=143±18,1 ms) als nach dessen Abklingen (N₂₀=26,6±3,5 ms; P₁₁₄=134±16,8 ms).Abgesehen davon war die Höhe der Komponenten N₂₀ und P₁₁₄ während des Fiebers wesentlich kleiner als nach dem Abklingen des Fiebers.Diese Unterschiede sind statistisch signifikant.Ferner fanden wir während des Fiebers bei zwei Patienten eine Verminderung der Erregungsleitungsgeschwindigkeit im N. medianus zwischen Handgelenk und Erbschen Punkt.

     

Pattern reversal visual evoked potentials in Japanese patients with multiple sclerosis.

Forty-seven Japanese patients with multiple sclerosis, 29 probable (clinically definite) and 18 possible, were studied by black-and-white checkerboard pattern reversal visual evoked potential and were compared with a control group of 20 healthy young adults. The major positive peak (P100) was found to be abnormal in 70% of all cases, 90% of probable cases and 39% of possible cases. P100 was delayed in 38% of all cases and was absent in 23% of all cases. None of the eyes showing a flat pattern response was in the acute stage of optic neuritis. The percentage of cases with no response (23% of all cases) was greater than any of the previously reported series from Western countries, substantiating the previously reported clinical features of oriental multiple sclerosis. The pattern response was absent only when testing eyes with severe visual impairment, whereas delayed latency of P100 was seen regardless of the severity of visual impairment, suggesting the usefulness of P100 latency for detecting subclinical optic nerve lesions.     

Pattern-onset visual evoked potentials in suspected multiple sclerosis.

Visual evoked potentials (VEPs) were obtained by monocular stimulation using a checkerboard pattern-reversal and pattern-onset technique. In 11 normal subjects, pattern-onset VEPs were generally larger, better defined, and less ambiguous than those elicited by pattern-reversal, because of the biphasic waveform characteristically obtained with pattern-onset stimulation. In 68 of 105 patients with possible multiple sclerosis, VEPs were normal in latency by both methods, and in nine adequate comparison was not possible. The incidence of normal VEPs to pattern-reversal was similar to that found in several other studies of patients with possible multiple sclerosis. Among the remaining 28 patients in whom VEP abnormalities were found, an increased latency was detected in 75% with the pattern-reversal technique, and in 96% by pattern-onset. In these patients, VEP abnormalities were obtained by monocular stimulation of each of 46 eyes, and among these the pattern-reversal technique yielded abnormalities in 59% and the pattern-onset method in 98%. These results indicate that VEPs elicited by pattern-onset are useful in investigating patients with suspected multiple sclerosis, and the diagnostic yield may be greater than with conventional pattern-reversal techniques.     

Ocular and cervical vestibular evoked myogenic potentials in multiple sclerosis patients

ObjectiveVestibular evoked myogenic potentials (VEMPs) are thought to provide useful information about brainstem functions, as the neural pathways of both ocular and cervical VEMPs pass through the brainstem. The aim of this study was to investigate the clinical value of ocular and cervical VEMP tests in the evaluation of brainstem involvement in multiple sclerosis (MS) patients and to assess their relation with clinical and cranial MRI findings.MethodsOcular and cervical VEMPs were recorded in 62 MS patients and 35 age and sex matched healthy volunteers. The latencies, amplitude asymmetry ratios of both VEMP responses and abnormality ratios (prolonged latencies and absent responses) were compared between the MS patients and the control group and among the groups of MS patients.ResultsoVEMP mean n1 and p1 latencies and cVEMP mean p13 latency were significantly prolonged in MS patients. Although the abnormality ratios of both VEMPs were higher in patients with brainstem clinical or MRI lesions, the correlation was not statistically significant. Both ocular and cervical VEMP latencies were significantly correlated with expanded disability status scale.ConclusionsAlthough there is no significant correlation with clinical or MRI findings, MS patients show high frequency of abnormality in VEMP tests, especially in oVEMP tests.SignificanceVEMP tests may be useful as an adjunct test in the evaluation of brainstem dysfunction in MS patients.     

Visual evoked potentials and the visuogram in multiple sclerosis.

Visual evoked potential (VEP) latency to a sinusoidal grating pattern was measured in each eye of 103 patients with multiple sclerosis (MS) and compared with results in a control group of 56 patients hospitalized for other neurological conditions. Of the 50 patients classified as having definite MS, 90% showed prolonged latency (over 131 msec) in one or both eyes. In each eye of 24 of the MS patients, psychophysical measurement of the detectability of grating patterns was obtained. This test was abnormal in 11 of 13 patients with definite MS, 3 of 4 with probable MS, and 5 of 7 with possible MS. There was no concordance between prolonged VEP latency and visual impairment as revealed by the psychophysical test. Apparently pathways determining VEP latency and spatial contrast detection may be unequally affected in MS.     

Visual and somatosensory evoked cortical potentials in multiple sclerosis.

The diagnostic value of the pattern reversal evoked cortical potential (VEP) and the somatosensory evoked cortical potential (SEP) has been compared in 50 patients with established or suspected multiple sclerosis. A prolonged latency of VEP was found in 96% of definite cases of multiple sclerosis, 58% of probable cases, and 20% of possible cases. A prolonged latency of SEP by stimulation of median or peroneal nerves or both was found in 86% of definite cases of multiple sclerosis, 83% of probable cases, and 50% of possibe cases. When combining the results of all three tests the diagnostic yield increased to 100%, 92%, and 50%, respectively.     

Visual evoked potentials in normal subjects and patients with multiple sclerosis

Visual evoked potentials (VEPs) by checkerboard pattern-reversal stimulation were recorded in 70 subjects aged 10–69 years and in 100 patients with definite, probable or possible multiple sclerosis (MS). Longer latencies and smaller amplitudes of the major positive component were found in male subjects, in old subjects and when the amplifier's band-pass was narrowed. Subjects 10–14 years old had longer latencies and higher amplitudes than mature adults. Based on findings in the normal material, the following three criteria were used in evaluating the recordings from patients: the latency, the side difference in latencies and the ratio of amplitudes between the two sides of the major positive component with various limits for the two sexes and different age groups.
The incidence of abnormal recordings was 85% for all the patients, 100% in 50 patients with definite, 70% in 50 patients with probable or possible MS, 73% in patients who had a history of spinal symptoms only, 98% if they had and 74% if they had not experienced optic neuritis. The incidence of abnormal findings increased with increasing duration of symptoms. All patients with visual acuity below 0.67 had abnormal VEPs.
The high incidence of abnormal recordings confirmed the value of the test in establishing the diagnosis, and suggested that the use of different normative values for sex and age may increase the diagnostic yield without increasing the number of false positive findings.     

Effects of grating spatial orientation on visual evoked potentials and contrast sensitivity in multiple sclerosis

Previous studies suggest a delay of pattern visual evoked potentials (PVEPs) in multiple sclerosis (MS) depending on grating orientation. We examined a group of 14 patients with definite MS recording PVEPs to vertical and horizontal grating and analysing latency and amplitude of P60, N70 and P100 waves. We evaluated contrast sensitivity (CS) to dark and bright bars of several spatial frequencies (SF). The aim was to evaluate the diagnostic value of evoked responses and CS in revealing involvement of cortical structures. PVEPs to 1 degrees cycle/degree (c/d) vertical bars were abnormal in 25% for P60, in 32% for N70 and in 36%, for P100; in 25%, 36% and 42% respectively at 4 c/d; as regards horizontal bars at 1 c/d we found alterations of P60, N70 and P100 in 11%, 19% and 27% respectively; at 4 c/d in 19%, 27%) and 35%. CS resulted more abnormal for vertical grating, with a maximum impairment for 3.7 c/d SF. We may conclude that the use of vertical grating in clinical routine is more reliable both for PVEPs and CS testing; in addition CS can be abnormal even with normal PVEPs: this could mean an early impairment of CS and provide useful indications about a subclinical involvement of visual cortex.     

多发性硬化患者前庭诱发肌源性电位的临床意义

目的研究多发性硬化(multiple sclerosis,MS)患者前庭诱发肌源性电位(vestibularevoked myogenic potentials,VEMPs)各参量的变化及临床意义,比较VEMPs与核磁共振、脑干听觉诱发电位对MS病变的检测能力。方法采用双耳短声刺激记录37例MS患者(有脑干症状21例、无脑干症状16例)和20名健康对照的VEMPs的潜伏期和振幅值,计算双侧在13ms左右出现的正波(p13)波幅潜伏期差值(Δp13)和振幅比(SR)。37例MS患者均做核磁共振成像,其中33例记录脑干听觉诱发电位。结果有脑干症状组和对照组相比,p13潜伏期显著延长[左侧为(13.84±2.57)ms和(12.20±1.10)ms,P<0.05;右侧为(14.69±2.96)ms和(12.10±2.60)ms,P<0.01],Δp13显著增大(1.63±1.82和1.00±1.44,P<0.01),而无脑干症状组差异无统计学意义。两组MS患者的p13-n23(在23ms左右出现的负波)振幅值与对照组相比均降低[左侧分别为(149.98±52.2)、(175.51±49.22)、(272.80±165.81)μV;右侧分别为(156.88±97.04)、(167.74±57.32)、(257.50±138.49)μV,P均<0.05],扩展的残疾功能量表评分与振幅有相关性(左侧r=0.45,右侧r=0.46,P均<0.05)。VEMPs与核磁共振相比,对病灶的检出率低(分别为33%与100%,P<0.05),与脑干听觉诱发电位相比差异无统计学意义。结论p13潜伏期及Δp13可作为判定MS前庭脊髓通路脱髓鞘的参考指标。VEMPs作为辅助诊断MS的一项新的诱发电位,对脑干病灶的诊断有一定临床参考意义。     

多发性硬化患者的MRI及多种诱发电位研究

目的探讨磁共振成像(MRI)和诱发电位(EPs)在诊断多发性硬化中的价值。方法对68例多发性硬化患者的头颅MRI、脑干听觉诱发电位、视觉诱发电位以及体感诱发电位等指标进行回顾性分析和比较。结果多发性硬化患者的头颅MRI、脑干听觉诱发电位、视觉诱发电位以及体感诱发电位的异常率分别为91.2%(62/68)、80.9%(55/68)、82.4%(56/68)和77.9%(53/68),且均发现多发性硬化的亚临床病灶;两项或多项联合检查的异常率较单项检查的异常率增高,差异有统计学意义(P<0.01)。结论头颅MRI和诱发电位检查有助于临床早期确诊多发性硬化,联合应用可使其敏感性提高。     

Effects of luminance on the pattern visual evoked potential in multiple sclerosis.

Pattern visual evoked potentials (PVEPs) were recorded at 5 levels of luminance from 26 patients with multiple sclerosis and from age-matched normal subjects. In normal subjects, the latency of both the major positive peak (P100) and the early positive peak (P60) was an inverse logarithmic function of pattern luminance. The increase in latency per unit log decrease in luminance was 12.1 msec for P100 and 5.7 msec for P60. Only 2 patients had entirely normal results. In 9 patients, the increase in latency of P100 per unit log decrease in luminance was abnormal. Of the 18 luminance-latency functions obtained from testing both eyes, 10 were abnormal, 6 showing a greater than normal increase in latency with decreasing luminance and 4 a less than normal increase. The 6 luminance-latency functions with a greater than normal increase in latency with decreasing luminance were all from patients without other evidence of optic nerve involvement. Pattern luminance, therefore, as well as patient selection, can significantly affect the proportion of abnormal PVEP latencies in any group of patients with possible, probable or definite multiple sclerosis. The abnormal response of the PVEP to changes in luminance and the different effects upon P100 and P60 indicate that the delayed PVEPs in patients with multiple sclerosis cannot be attributed solely to slowing of conduction in the optic nerve.