Multiple sclerosis. Magnetic resonance imaging, evoked potentials and cerebrospinal fluid analysis

We have studied 27 patients with multiple sclerosis (22 definite, 5 probable) by magnetic resonance imaging (MRI), visual evoked potentials (VEPs), brainstem auditory evoked potentials (BAEPs), and oligoclonal bands (OBs) in cerebrospinal fluid (CSF), MRI was altered in 92.5% of the cases, the presence of OBs in CSF was revealed in 73.1% of the examined patients, the frequency of evoked potentials (EPs) alteration was VEPs = 59.3% and BAEPs = 29.6%, at least one of the two EPs occurred positive in 66.6% of the cases. Our data confirm the more sensitive value of MRI compared with OBs and EPs studies in assessing MS, and stress the utility of the combined use of these tests.     

Correlation between multimodal evoked potentials and magnetic resonance imaging in multiple sclerosis

Summary Sixty multiple sclerosis (MS) patients (33 definite, 13 probale and 14 suspected were investigated by computed tomography (CT), magnetic resonance imaging (MRI), multimodality evoked potentials (EPs) and cerebrospinal fluid (CSF) electrophoresis. MRI abnormalities were found in 50 cases, while at least one abnormal evoked potential was detected in each of 52 cases. Brain-stem auditory evoked potentials were more sensitive than MRI for the detection of brainstem involvement. All the patients with oligoclonal bands had abnormal MRI and none of the patients with normal MRI had oligoclonal bands in the CSF. The number and the extent of MRI lesions were significantly correlated with the duration of disease and with the degree of disability. Our observations stress the importance of the combined use of MRI and EPs in detecting silent CNS lesions in MS patients.     

Acute myelopathy of unknown aetiology: a clinical,neurophysiological and MRI study of short-and long-term prognostic factors

Brain and spinal cord magnetic resonance imaging (MRI), multimodal evoked potentials (EPs) and cerebrospinal fluid (CSF) analysis were performed in 27 patients with acute myelopathy of unknown aetiology (AMUA), to detect the diagnostic and prognostic values of paraclinical tests at presentation. Spinal cord MRI was abnormal in 56% and brain MRI in 33% of the patients. Visual EPs were abnormal in 7%, median somatosensory EPs in 17%, tibial somatosensory EPs in 56% and motor EPs in 35% of the cases examined. Brain-stem acoustic EPs were normal in all the patients. CSF oligoclonal bands (OBs) were detected in 30% of cases. The patients were divided into subgroups according to the short-term clinical outcome (complete, partial or absent recovery). There were no significant differences among the three groups as regards MRI findings. Patients with complete recovery showed a significantly lower frequency of tibial somatosensory EP and motor EP abnormalities. According to the paraclinical findings at onset and on the basis of a long-term clinical follow-up (mean duration 24 months), 6 patients were diagnosed as having clinically definite multiple sclerosis, while 21 did not develop further neurological disturbances. Only the presence of CSF OBs was significantly more frequent in patients with definite multiple sclerosis. Our study indicates that EPs exploring spinal cord function are more powerful than spinal MRI for predicting the short-term outcome of AMUA, while the combined use of brain MRI and CSF OBs has the highest negative predictive value for the subsequent development of clinically definite multiple sclerosis.     

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。     

Exploring brainstem function in multiple sclerosis by combining brainstem reflexes,evoked potentials,clinical and MRI investigations

ObjectiveTo investigate vestibulo-masseteric (VMR), acoustic-masseteric (AMR), vestibulo-collic (VCR) and trigemino-collic (TCR) reflexes in patients with multiple sclerosis (MS); to relate abnormalities of brainstem reflexes (BSRs) to multimodal evoked potentials (EPs), clinical and Magnetic Resonance Imaging (MRI) findings.MethodsClick-evoked VMR, AMR and VCR were recorded from active masseter and sternocleidomastoid muscles, respectively; TCR was recorded from active sternocleidomastoid muscles, following electrical stimulation of the infraorbital nerve. EPs and MRI were performed with standard techniques.ResultsFrequencies of abnormal BSRs were: VMR 62.1%, AMR 55.1%, VCR 25.9%, TCR 58.6%. Brainstem dysfunction was identified by these tests, combined into a four-reflex battery, in 86.9% of cases, by EPs in 82.7%, MRI in 71.7% and clinical examination in 37.7% of cases. The sensitivity of paired BSRs/EPs (93.3%) was significantly higher than combined MRI/clinical testing (70%) in patients with disease duration ⩽6.4 years. BSR alterations significantly correlated with clinical, EP and MRI findings.ConclusionsThe four-BSR battery effectively increases the performance of standard EPs in early detection of brainstem impairment, otherwise undetected by clinical examination and neuroimaging.SignificanceMultiple BSR assessment usefully supplements conventional testing and monitoring of brainstem function in MS, especially in newly diagnosed patients.     

Comparative impact of paraclinical studies in establishing the diagnosis of multiple sclerosis

We prospectively examined 58 patients with suspected or confirmed multiple sclerosis (MS) to evaluate the impact of paraclinical studies (evoked potentials (EPs) and magnetic resonance imaging (MRI] in the diagnostic evaluation of these patients. All patients had cranial MRI studies, brain-stem auditory (BAEP), visual (VEP), posterior tibial (PTN-SSEP) and median somatosensory (MN-SSEP) EPs. Patients were categorized according to criteria of Poser et al. initially without knowledge of paraclinical studies. On the basis of clinical history, neurological examination and CSF chemical analysis, there were 18 (31%) clinically definite (CD). 10 (17%) laboratory supported definite (LSD), 13 (22%) clinically probable (CP) MS cases; 17 (29%) cases could not be classified. By providing electrophysiological and/or anatomical evidence for a 'second lesion,' paraclinical studies permitted 25 patients to move from one diagnostic category to another, reflecting an increased certitude of the diagnosis. Twelve moved to CDMS by either MRI or one EP study. Four moved to CDMS on the basis of MRI only, and four moved to CDMS by VEP only. Five moved from an unclassified status to either LSDMS or CPMS by PTN-SSEP (2), by PTN-SSEP or MRI (1), by MRI or VEP (1) and by VEP only (1). Thus, the diagnosis of MS was refined in 28% of the patients (7/25) by incorporation of EPs alone whereas cranial MRI by itself increased the diagnostic certainty in only 16% (4/25). In the remaining 56%, the diagnosis was refined by use of either EPs or MRI. Overall, EP provided evidence for a 'second lesion' in 36% of the patients (21/58) and MRI 31% (18/58). While MRI may ultimately prove the single most useful paraclinical study in the diagnosis of MS. VEPs, and PTN-SSEPs by assessing areas currently not imaged by MRI, remain essential in patient evaluation. Changes in EPs and MRI technology will undoubtedly redefine the role of these diagnostic techniques.     

Influence of antipsychotic and antidepressant drugs on evoked potential correlates of psychosis

This study aimed to (i) determine the changes in evoked potentials (EPs) associated with hospital treatment involving either antipsychotic (AP) drugs, tricyclic (TTR) drugs, or no medication (NM); (ii) determine which EP changes may be direct drug effects; (iii) evaluate effects of testing patients receiving AP and TR drugs on psychiatric correlates of EPs. Somatosensory (SEP) to left and right median nerve stimuli, visual (VEP), and auditory (AEP) EPs were recorded from one eye and 14 scalp leads. Patients were tested before and during AP (N = 28), TR (N = 10), or NM (N = 15) treatments; results of 35 age- and sex-matched nonpatients were compared with predrug and drug test results of 35 patients. Main findings included (i) with AP and TR drugs, SEP peak P30 amplitude tended to decrease and SEP N130 to increase; (ii) with AP drugs and NM, VEP amplitudes decreased; (iii) AEP amplitudes increased with AP drugs; (iv) changes in amplitude measures did not differ significantly between AP, TR, and NM treatments; (v) marked later SEP amplitude differences between patients and nonpatients were about the same for pretreatment and drug tests; (vi) patient-control differences were greater with drugs for VEPs and less with drugs for AEPs. It was concluded that later SEP amplitude correlates of psychopathology are little influenced by AP and TR drugs, but that VEP and AEP results are modified.     

Long-term follow-up of isolated optic neuritis: the risk of developing multiple sclerosis, its outcome, and the prognostic role of paraclinical tests

We evaluated the risk of developing clinically definite multiple sclerosis (CDMS) after an acute attack of isolated optic neuritis (ON) in 112 patients, in relation to demographic and paraclinical findings. Patients were examined by brain MRI, CSF analysis, and multiple evoked potentials (EPs); 10 were lost to follow-up, and the other 102 were enrolled in a prospective study (follow-up duration 6.3 ± 2.2 years). Of these, 37 (36.3%) developed CDMS after a mean interval of 2.3 ± 1.6 years. The risk of developing CDMS was 13% after 2 years, 30% after 4, 37% after 6, and 42% after 8 and 10 years. Gender, age, and season of ON onset did not affect the risk. MS occurred in 37 of 71 patients (52.1%) with one MRI lesion or more; no patient with a normal MRI developed the disease. MS developed more frequently in patients with intrathecal IgG synthesis than in those without (43% vs. 28%), but the difference was not statistically significant. Multiple EPs showed a slight predictive value only including somatosensory EPs of the lower limb. Multiple sclerosis was mild in most cases (EDSS 2.2 ± 1.9). The EDSS was less than 4 in 32 cases (86%), between 4 and 6 in 2 (5%), higher than 6.5 in 3 (8%). Received: 27 July 1998 Received in revised form: 3 February 1999 Accepted: 7 February 1999     

Correlations between clinical and magnetic resonance imaging findings in multiple sclerosis

40 patients with multiple sclerosis were investigated by magnetic resonance imaging (MRI) and computer tomography (CT). Additionally, cerebrospinal fluid (CSF) findings and evoked potentials (EPs; visual, brainstem) were evaluated. MRI findings were abnormal in 85% of the patients, whilst CT scan showed pathological changes in only 23%. The sensitivity for detecting lesions was significantly higher for MRI than CT. 86% of 23 patients with a duration of disease of more than 1 year had pathological MRI findings, and MRI was abnormal in 82% of 17 patients with a duration of symptoms up to 1 year. All patients with abnormal MRI had at least one other pathological laboratory finding. CT revealed only large lesions, and in patients with abnormal CT MRI visualized lesions more extensively. Additionally, brainstem lesions could be verified in 6 patients and spinal cord lesions in 3 cases. CSF was abnormal in 86%, and positive MRI findings occurred in 26 of 31 patients with abnormal CSF. Abnormalities of EPs were found in 76%, and MRI was positive in 24 of 33 patients with abnormal EPs.     

Conversion to multiple sclerosis after a clinically isolated syndrome of the brainstem: cranial magnetic resonance imaging,cerebrospinal fluid and neurophysiological findings

BACKGROUND AND AIM: Conversion to multiple sclerosis (MS) after optic neuritis and myelitis has been thoroughly studied; however, limited data are available regarding conversion to MS after a clinically isolated syndrome of the brainstem (CISB). The aim of this study was to investigate conversion to MS in patients with CISB. METHODS: Fifty-one patients with CISB were prospectively studied. Cranial magnetic resonance imaging (MRI), determination of oligoclonal bands (OBs) in the cerebrospinal fluid (CSF) and evoked potentials (EPs) were performed. Based on conversion to MS at follow-up, the sensitivity, specificity, accuracy and positive and negative predictive values of these tests were calculated. RESULTS: Clinically definite MS developed in 18 (35%) patients after a mean follow-up of 37 months. Paty's MRI criteria showed a sensitivity of 89%, a specificity of 52% and an accuracy of 65%; Fazekas' criteria showed a sensitivity of 89%, a specificity of 48% and an accuracy of 63%; Barkhof's criteria showed a sensitivity of 78%, a specificity of 61% and an accuracy of 67%. The presence of OBs in the CSF showed a sensitivity of 100%, a specificity of 42% and an accuracy of 63%. No differences for neurophysiological parameters were found between patients who did and those who did not convert to MS. CONCLUSION: Fulfilling Paty's, Fazekas' or Barkhof's MRI criteria and the presence of OBs in the CSF are associated with a higher risk of conversion to MS in patients with CISB. Determination of OBs in the CSF has the greatest sensitivity of all tests. Barkhof's MRI criteria have greater specificity (although less than previously published for mixed cohorts of clinically isolated syndromes) in predicting conversion to MS for CISB than either Paty's or Fazekas' criteria.     

Isolated optic neuritis and its prognosis for multiple sclerosis: a clinical and paraclinical study with evoked potentials. CSF examination and brain MRI

Our study evaluated the frequency of developing multiple sclerosis (MS) after acute isolated optic neuritis (ON), the possible association with risk factors (gender, age), and the diagnostic and prognostic role of paraclinical tests. We studied 100 ON patients (mean age 28.9 years: SD 8.9): 85 patients were regularly followed up. Sixty-six patients underwent multimodality evoked potential (EP) test, CSF examination and brain MRI within six months of the onset of ON.Over a mean follow-up of 5.2 years, MS occurred in 28/85 cases. The risk of developing MS after four years was 0.35 at life-table analysis, regardless of gender or age at the onset of ON. Visual EPs in unaffected eyes were abnormal in 25.4%, brainstem auditory EPs in 6.5%, somatosensory EPs in 8.1%, upper limb motor EPs in 6.8% of the tested patients; intrathecal IgG synthesis was revealed in 51.7% and MRI lesions in 73.8%. Fifty-one of the patients who underwent paraclinical tests were followed up for more than one year, and MS occurred in 13 cases. All of these presented MRI lesions, nine intrathecal IgG synthesis, and two abnormal extraocular EPs. The risk of developing MS after four years was 0.33 in patients with MRI lesions; the simultaneous presence of intrathecal IgG synthesis increased the risk to 0.46.This study was partially supported by Associazione Amici Centro Studi Sclerosi Multipla, Gallarate, Italy.     

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。     

Multiple sclerosis: magnetic resonance imaging, evoked responses, and spinal fluid electrophoresis

Magnetic resonance images (MRI), evoked responses (ER), and CSF findings were compared in 39 patients with possible, probable, or definite MS. MRI disclosed multiple lesions (72%) more often than ERs (55%) in the total group of patients. In possible MS, MRI showed multiple lesions in 71%, and ER abnormalities were found in 41%. MRI is the preferred test for patients with suspected MS, but ERs are useful when MRI is normal and in the evaluation of optic nerve or spinal cord lesions.     

Neurological stamp. Humulus lupulus (hop).

The yield of paraclinical tests was evaluated in a prospective study of 189 consecutive patients referred for suspected multiple sclerosis (142 patients with multiple sclerosis, 47 non-multiple sclerosis patients on discharge). Patients were first classified according to the Poser criteria by the clinical findings. Subsequently, the results of paraclinical tests (cranial MRI, visually evoked potentials (VEPs), somatosensory evoked potentials by tibial nerve stimulation (SSEPs), motor evoked potentials (MEPs), and analysis of CSF for oligoclonal banding and IgG-index (CSF)) were taken into account. The percentage of reclassified patients (reclassification sensitivity, RS) was always lower than the percentage of abnormal results (diagnostic sensitivity, DS), and the divergence of RS v DS differed between the tests (60% v 84% in MRI, 31% v 77% in CSF, 29% v 37% in VEPs, 20% v 68% in MEPs, and 12% v 46% in SSEPs respectively). False reclassifications of non-multiple sclerosis patients to multiple sclerosis would have occurred with all tests (MRI: six of 47 patients, (reclassification specificity 88%); CSF: one (98%); VEPs: two (96%); MEPs: two (96%); SSEPs: four (91%); P < 0.05). Although MRI had superior diagnostic capacity, 57 of the 142 patients with multiple sclerosis were not reclassified by the MRI result, 12 of whom were reclassified by CSF and 18 by one of the evoked potential (EP) studies. Of the 98 patients not reclassified by CSF, 53 were reclassified by MRI and 39 by EPs. The results suggest that for the evaluation of paraclinical tests in suspected multiple sclerosis, comparison of diagnostic sensitivities is inappropriate. In general, a cranial MRI contributes most to the diagnosis; however, due to its comparatively low specificity and its considerable number of negative results, EP or CSF studies are often useful to establish the diagnosis of multiple sclerosis.     

Brainstem auditory and somatosensory evoked potentials in neuro-Beh?et's syndrome

Brainstem auditory evoked potentials (BAEPs) and somatosensory evoked potentials after median nerve stimulation (MN-SEPs) and after posterior tibial nerve stimulation (PTN-SEPs) were studied in 17 patients with neuro-Beh?et's syndrome (NB). Eleven patients (64.7%) showed an absence of wave I, III or V or a prolongation of the interpeak latency I-III, or III-V in BAEPs. Six patients (37.4%) showed a prolongation in the latency of cortical P37 of PTN-SEPs and/or the interpeak latency EP-N13 or N13-N18 of MN-SEPs. The BAEP and SEP abnormalities indicated a conduction failure of the acoustic lateral lemniscus pathway and the medial lemniscus pathway in the brainstem of the patients with NB. Abnormal EPs can provide sensitive information which shows the presence of subclinical lesions in the central nervous system.     

Magnetic resonance imaging of the head in the diagnosis of multiple sclerosis: a prospective 2-year follow-up with comparison of clinical evaluation, evoked potentials, oligoclonal banding, and CT

We previously compared the diagnostic capabilities of MRI of the head with CT, evoked potentials, and CSF oligoclonal banding (OB) analysis in a prospective evaluation of 200 patients with suspected multiple sclerosis (MS). To examine the ability of MRI and other paraclinical tests to predict the diagnosis of clinically definite MS (CDMS), we did a systematic clinical follow-up of 200 patients who were previously reported. In that study, 85 of 200 could be diagnosed as having laboratory-supported definite MS (LSDMS). In follow-up, we excluded one patient diagnosed as LSDMS who in retrospect was considered to have had CDMS at entry and 15 patients who were eventually diagnosed as having other diseases. After a mean follow-up of 2.1 years, 55 of the remaining 184 patients (30%) had developed CDMS. Thirty-eight of 84 patients with an original diagnosis of LSDMS (45%) and 17 of the remaining 100 patients with suspected MS (17%) had become CDMS. Forty-six of the 55 patients who developed CDMS in follow-up (84%) had an initial MRI that was strongly suggestive of MS. Fifty-two of those 55 CDMS patients (95%) had at least one MS-like abnormality on MRI when originally studied. In contrast, 38 of 55 (69%) had CSF OB, 38 of 55 (69%) had an abnormal VEP, 35 of 55 (64%) had an abnormal SEP, and 21 of 55 (38%) had an abnormal CT when first studied. MRI was the most sensitive single paraclinical test for predicting CDMS. CDMS developed during follow-up in 46 of the 94 patients (49%) whose initial MRI was strongly suggestive of MS.(ABSTRACT TRUNCATED AT 250 WORDS)     

Neurophysiological evaluation of the central nervous impulse propagation in patients with sensorimotor disturbances

Motor evoked potentials (MEPs) to transcranial stimulation (TCS) and somatosensory evoked potentials to median nerve stimulation (MN-SEPs) were examined in 74 patients affected by multiple sclerosis (MS = 49 cases), amyotrophic lateral sclerosis (ALS = 9 cases), cervical cord lesions (7 cases), Parkinson's disease (PD = 5 cases), Huntington's chorea (HC = 2 cases), Wilson's disease (WD = 1 case), subacute combined degeneration (SCD = 1 case). MN-SEPs were altered in 38% of arms in MS with a higher incidence in clinically affected than in clinically 'silent' arms (= 77.8% vs. 27.5%). MEP alterations were found in 54% of examined arms, mostly because of a prolongation of the motor CCT. This index was invariably altered in the affected arms, whilst it was involved in 40% of the 'silent' ones. Twelve out of 18 arms displayed abnormal MEPs in ALS. These were mainly due to an absent response, even if moderate motor CCT prolongation and 'giant' MEPs were also encountered. MN-SEPs were altered in 3/18 arms. By recording MEPs from proximal and distal upper limb muscles, cues on the level of abnormal propagation were obtained in patients suffering from 'focal' lesions of the spinal cord. Combining SEP records enhanced the diagnostic yield in this field. Both MEPs and SEPs were normal in patients with PD and HC, whilst abnormally prolonged CCTs were found in the case with WD. MEP and SEP recording revealed central propagation abnormalities coupled to a severe clinical picture of the peripheral nerve involvement (as in the case of SCD).     

Acute- and insidious-onset myelopathy of undetermined aetiology: contribution of paraclinical tests to the diagnosis of multiple sclerosis

Summary Brain magnetic resonance imaging (MRI), multimodality evoked potentials (EPs) and cerebrospinal fluid examination were performed in 42 patients with myelopathy of undetermined aetiology in order to detect abnormalities usually related to multiple sclerosis (MS). Patients were divided into three groups: insidious-onset myelopathy with only motor signs (group A; 11 patients), with both motor and sensory signs (group B; 18 patients) and acute-onset myelopathy (group C; 13 patients). Multiple brain MRI lesions were found in 18 patients (2 of group A, 13 of group B and 3 of group C). Another 7 patients had a single white-matter lesion. Visual EPs were abnormal in 21 and brain-stem auditory EPs in 12 patients. Paraclinical tests supported the diagnosis of MS in 25 patients (60%) by showing subclinical brain abnormalities. Oligoclonal bands were found in 16 of these 25 patients. The findings strongly suggest a diagnosis of MS in the patients of group B.     

The diagnostic significance of long-latency reflexes in multiple sclerosis

Reflexes of thenar muscles after median or radial superficial nerve stimulation have been investigated in both hands of 47 patients with probable or definite multiple sclerosis (MS) and compared with somatosensory evoked potentials (SEPs) to median nerve stimulation. A delay or absence of long-latency reflexes (LLRs) was found as pathological patterns. The results after median or radial superficial nerve stimulation were usually both pathologic or both normal except in cases with latencies at the upper limit of normal values. Pathological results of reflex testing were obtained in 61% of the patients with probable MS and in 79% of those with definite MS. Abnormal SEPs were found in 44% of the patients with probable MS compared to 62% with definite MS. All cases which had pathologic SEPs also had pathologic LLR. Hence, LLR testing detected more abnormalities than the routine median nerve SEP testing that has been used.     

Evoked potentials in suspected multiple sclerosis: diagnostic value and prediction of clinical course

Pattern visual, somatosensory and brainstem auditory evoked potentials (EPs) of 14 patients with definite multiple sclerosis, 222 patients suspected of having multiple sclerosis, 26 patients with isolated optic neuritis and 40 patients with a chronic not diagnosed neurologic disorder, were compared with their clinical diagnoses on 2 1/2-year follow-up. In the MS suspects, an EP abnormality demonstrating a clinically silent lesion in any modality (65 patients) was associated with a 71% chance of clinical deterioration (48% chance of definite MS within the follow-up period). Normal EPs (121 patients) were associated with a 16% chance of deterioration (4% chance of definite MS). EPs in patients in whom the only abnormalities confirmed known lesions (36 patients) did not predict follow-up status. Visual EPs demonstrated clinically silent lesions more frequently than somatosensory and auditory EPs (22%, 12% and 5% of patients). Only one of the patients with optic neuritis and 3 of the chronic not diagnosed group had EPs demonstrating clinically silent lesions. CSF and NMR studies also correlated with follow-up in subseries of the patients.