Oligoclonal bands in Devic’s neuromyelitis optica and multiple sclerosis: differences in repeated cerebrospinal fluid examinations

We studied repeated cerebrospinal fluids of patients with Devic’s neuromyelitis optica (NMO) and multiple sclerosis (MS). Variations of oligoclonal bands (OBs) had opposite trends in the two groups. In MS, O Bs were detected in 399 of 411 patients (97%) and never disappeared. In NMO, O Bs were detected in three of 11 patients (27%) and always disappeared. The hypothesis that NMO and MS follow distinct patho genetic pathways is supported by our findings, which can be useful for the differentiatio n of NMO from MS.

ICHD-II Diagnostic Criteria for Tolosa—Hunt Syndrome in Idiopathic Inflammatory Syndromes of the Orbit and/or the Cavernous Sinus

A bibliographical search was conducted for papers published between 1999 and 2007 to verify the validity of International Classification of Headache Disorders (ICHD)-II criteria for the Tolosa-Hunt syndrome (THS) in terms of (i) the role of magnetic resonance imaging (MRI); (ii) which steroid treatment should be considered as adequate; and (iii) the response to treatment. Of 536 articles, 48, reporting on 62 patients, met the inclusion criteria. MRI was positive in 92.1% of the cases and it normalized after clinical resolution. There was no evidence of which steroid schedule should be considered as adequate; high-dose steroids are likely to be more effective both to induce resolution and to avoid recurrences. Pain subsided within the time limit required by the ICHD-II criteria, but signs did not. We conclude that THS diagnostic criteria can be improved on the basis of currently available data. MRI should play a pivotal role both to diagnose and to follow-up THS.

The DYMUS questionnaire for the assessment of dysphagia in multiple sclerosis

Swallowing problems can be relevant, even if underestimated, in Multiple Sclerosis (MS) patients. However, no specific questionnaire for the assessment of dysphagia in MS is available. We built a questionnaire (DYsphagia in MUltiple Sclerosis, DYMUS) that was administered to 226 consecutive MS patients (168 F, 58 M, mean age 40.5 years, mean disease duration 10.1 years, mean EDSS 3.1) during control visits in four Italian MS Centres. DYMUS was abnormal in 80 cases (35%). The patients who claimed to have swallowing problems had a significantly higher mean DYMUS score that the other patients (p<0.0001). Mean DYMUS scores were significantly higher in the progressive forms (p=0.003). DYMUS values were significantly correlated to EDSS (p=0.0007). DYMUS showed a very good internal consistency (Cronbach's alpha 0.877). Factor analysis allowed us to sub-divide DYMUS in two sub-scales, 'dysphagia for solid' and 'dysphagia for liquid', both of them had a very good internal consistency (Cronbach's alpha 0.852 and 0.870 respectively). DYMUS demonstrated to be an easy and consistent tool to detect dysphagia and its main characteristics in MS. It can be used for preliminary selection of patients to submit to more specific instrumental analyses, and to direct toward programs for prevention of aspiration.

Memory guided saccades in mesial temporal lobe epilepsy with hippocampal sclerosis

OBJECTIVE

Mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) may involve extrahippocampal areas of structural and functional damage. The incidence and the features of this damage are still a matter of debate and vary depending on the method applied. Memory guided saccades (MGSs) with a memorization delay longer than 20s can be used reliably to evaluate the parahippocampal cortex.

METHODS

MGSs with 3 and 30s memorization delays were recorded with the search coil technique in six patients affected by right MTLE-HS, and in 13 healthy controls.

RESULTS

The patients were not able to reduce the MGSs residual amplitude error after the first saccade with a 30s memorization delay. This finding was more evident with leftward saccades.

CONCLUSIONS

MGS abnormalities suggested the functional involvement of the right parahippocampal cortex in most of the patients with MTLE-HS, and this supports the clinical and anatomopathological heterogeneity of the disease.

SIGNIFICANCE

MGSs can be used in patients with right MTLE-HS to detect a possible functional involvement of the ipsilateral parahippocampal cortex.

Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is an autoimmune acute peripheral neuropathy. Frequently a flu-like episode or a gastroenteritis precede GBS, and the cross-reactivity between microbial and neural antigens partly explains the pathophysiology of the disease and the possible detection of antiganglioside antibodies. The weakness reaches its nadir in 2-4 weeks: the patients may be chair- or bed-bound, may need artificial ventilation and frequently experience dysautonomic dysfunction; 5-15% of the patients die and more patients are left with a disabling motor deficit and/or fatigue. Electrophysiology and cerebrospinal fluid evaluation support the diagnosis. The treatment of GBS is multidisciplinary, and both plasma exchange and high dose immunoglobulin (IVIg) are effective in reducing both the severity of the disease and the residual deficits. Finally, steroids are not effective in GBS.

Bayesian mapping of multiple sclerosis prevalence in the province of Pavia, northern Italy

The geographical analysis of a disease risk is particularly difficult when the disease is non-frequent and the area units are small. The practical use of the Bayesian modelling, instead of the classical frequentist one, is applied to study the geographical variation of multiple sclerosis (MS) across the province of Pavia, Northern Italy. 464 MS-affected individuals resident in the province of Pavia were identified on December 31st 2000. The overall prevalence was 94 per 100,000 inhabitants. This estimate indicates an increasing MS prevalence in the province, in accordance with the vast majority of the Italian areas where prevalence studies have been repeated. We mapped the geographical variation of MS prevalence across the 190 communes of the province both with a classical approach and a Bayesian approach. The frequentist approach produced an extremely dishomogeneous map, while the Bayesian map was much smoother and more interpretable. Our study underlines the usefulness of Bayesian methods to obtain reliable maps of disease prevalence and to identify possible clusters of disease where to carry out further epidemiological investigations.

Analysis of Chlamydia pneumoniae-specific oligoclonal bands in multiple sclerosis and other neurologic diseases

OBJECTIVE

Paired serum and cerebrospinal fluid (CSF) specimens were investigated for Chlamydia pneumoniae-specific oligoclonal bands (OCBs) to determine band specificity in multiple sclerosis (MS).

MATERIAL AND METHODS

Serum and CSF samples were collected from patients with relapsing-remitting MS (n = 56), other inflammatory (n = 18) or non-inflammatory (n = 15) neurologic diseases, and from 10 healthy controls. OCBs were determined with affinity immunoblotting of C. pneumoniae-specific IgG onto antigen-coated nitrocellulose paper after protein separation with agarose isoelectric focusing.

RESULTS

Chlamydia pneumoniae-specific OCBs were present in 5 of 56 patients with MS, and in 3 of 18 patients with other inflammatory neurologic diseases.

CONCLUSIONS

The intrathecal production of C. pneumoniae-specific oligoclonal IgG occurs in a minority of patients with MS. This intrathecal anti-C. pneumoniae reactivity is likely part of a polyspecific humoral immune response in MS.

Interferon gamma and interleukin 4 producing T cells in peripheral blood of multiple sclerosis patients undergoing immunomodulatory treatment

Intracellular cytokine flow cytometry was used to analyse the percentages of interferon (IFN) gamma and interleukin (IL)-4 producing T cells in the peripheral blood of multiple sclerosis patients, before and after immunomodulatory treatment, and of healthy controls. After six months of treatment, different doses of IFN beta1a (Avonex or Rebif) decreased CD4+ (Th1, Th2) and CD8+ (Tc1) cells to a similar extent, without affecting the Th1/Th2 ratio. These T cell subsets were unmodified after nine months of glatiramer acetate (Copaxone) treatment, and after six day courses of high dose 6-methylprednisolone. The data suggest that IFN beta1a produces sustained downmodulation of IFN gamma and IL-4 producing T cells in vivo, which may contribute to its therapeutic efficacy; that glatiramer acetate possibly acts without altering non-specific cellular immunity; and that glucocorticoid induced lymphocytopenia does not affect the percentages of Th1, Th2, and Tc1 cells; at least in the periphery, none of the treatments caused a Th1 to Th2 shift that could account for their respective therapeutic effects.

Ocular motor myotonic phenomenon in myotonic dystrophy

OBJECTIVE

To detect disconjugate ocular motor abnormalities and a possible extraocular muscle myotonic phenomenon in patients with myotonic dystrophy (MyD).

METHODS

The magnetic scleral search coil technique was used to record monocularly the small (25 degrees ) and large (50 degrees ) saccades, which were paced to two interstimulus intervals (ISIs), one short (1 s), the other long (5 s). The case study comprised 20 patients with MyD, 10 patients with multiple sclerosis (MS), and 10 controls. The amplitude, duration, peak velocity, and skewness of the velocity profile (ratio between the acceleration and the deceleration periods) of each saccade were measured. The disconjugate parameters (difference between the two eyes of the same measure), and the myotonic parameter (the maximal (as absolute value) short-long ISI difference between the same measures) were considered.

RESULTS

The disconjugate parameters were the same in all three groups. The mean values of myotonic parameters found in patients with MyD for duration (for both small and large target displacements) and skewness (for small target displacements only) differed from those found for both the MS and the control groups. Additionally, the occurrence of individual patients presenting with abnormal duration and skewness parameters was higher in the MyD than in the MS group. In patients with MyD, the saccade duration was longer for long than for short ISI; the effect derived from a prolongation of the acceleration period, which manifested as an increase in skewness.

CONCLUSION

The results can be explained by a combination of the myotonic and the warm up phenomena. A delay in the relaxation (myotonia) of the extraocular muscle may be more evident after a long fixation period (long ISI) and it may improve by increasing saccade pacing (short ISI-warm up). This phenomenon is slight, and is unlikely to affect saccade performance significantly, but it may provide some insight into the nature of the disorder affecting extraocular and skeletal muscles in myotonic dystrophy.

Vestibular evoked myogenic potentials: test-retest reliability

Vestibular evoked myogenic potentials (VEMPs) are myogenic responses induced by stimulation of the saccular macula by intense sound stimuli. The responses are recordable from the sternocleidomastoid (SCM) muscles. We recorded VEMPs from normal subjects (up to three times in each subject) to identify: i) the best recording procedures, ii) the reliability, and iii) the normal limits for both individual point and test-retest evaluation. We adopted a recording setting in which the subjects were asked to simultaneously activate both SCM muscles by pushing their forehead against a load cell during a bilateral acoustic stimulation. This system enabled subjects to monitor their intensity of SCM activation and to keep intensity constant; us to record VEMPs from both sides simultaneously, and thus to minimize the duration of the recording session. For each subject we considered the mean and the difference (divided by the mean) of the values derived from the two SCM muscles of the latency of the P13 and N23 components and of the P13-N23 peak-to-peak amplitude. Reliability was evaluated by estimate of the intraclass correlation coefficient, and was good or excellent for all parameters, with the exception of the P13-N23 amplitude side-difference. To take advantage of all the data available, we computed the normal limits for both individual point and test-retest evaluation by means of the variability indices used for the evaluation of reliability. In this system, VEMP recording is simple, inexpensive and rapid. It is well tolerated by subjects, and easily implemented in laboratories equipped for evoked potential recording.

Polymorphic markers in MHC class II/III region: a study on Italian patients with myasthenia gravis

With an Italian case series of 81 Italian patients and 130 controls, we analysed associations between myasthenia gravis (MG) and genetic polymorphisms in the MHC class II/III region. Increases in the frequency of the TNF-B*1, C4A*Q0, C4B*1, DRB1*03 supratype, which is likely part of the 8.1 ancestral haplotype, were maximal in females with early onset (EO) MG vs. controls [p<0.05, relative risk (RR)=9.9]. These patients showed neither a significantly high frequency of thymic hyperplasia, nor high levels of serum anti-acethylcholine receptor antibodies. The DRB1*03 allele was absent in patients with thymoma; however, in comparison with controls, occurrence of this marker was frequent in MG patients (p<0.005; RR=6.2), more frequent in females (p<0.005; RR=7.8) and most frequent in EOMG female patients (p<0.005; RR=15.1). Analysis of the TNF-B*1, C4A*Q0, C4B*1, DRB1*03 supratype and its recombinants showed that the MHC region between C4 and TNF might contain genes that influence susceptibility to MG in females. Polymorphic markers within the supratype, e.g. TNF-B*1 and C4A*Q0, might contribute to pathogenetically significant abnormalities in immune responses in a subset of female MG patients. The combined effect of other intervening genes cannot be excluded.

Predicting secondary progression in relapsing-remitting multiple sclerosis: a Bayesian analysis

With the aid of a Bayesian statistical model of the natural course of relapsing remitting Multiple Sclerosis (MS), we identify short-term clinical predictors of long-term evolution of the disease, with particular focus on predicting onset of secondary progressive course (failure event) on the basis of patient information available at an early stage of disease. The model specifies the full joint probability distribution for a set of variables including early indicator variables (observed during the early stage of disease), intermediate indicator variables (observed throughout the course of disease, prefailure) and the time to failure. Our model treats the intermediate indicators as a surrogate response event, so that in right-censored patients, these indicators provide supplementary information pointing towards the unobserved failure times. Moreover, the full probability modelling approach allows the considerable uncertainty which affects certain early indicators, such as the early relapse rates, to be incorporated in the analysis. With such a model, the ability of early indicators to predict failure can be assessed more accurately and reliably, and explained in terms of the relationship between early and intermediate indicators. Moreover, a model with the aforementioned features allows us to characterize the pattern of disease course in high-risk patients, and to identify short-term manifestations which are strongly related to long-term evolution of disease, as potential surrogate responses in clinical trials. Our analysis is based on longitudinal data from 186 MS patients with a relapsing-remitting initial course. The following important early predictors of the time to progression emerged: age; number of neurological functional systems (FSs) involved; sphincter, or motor, or motor-sensory symptoms; presence of sequelae after onset. During the first 3 years of follow up, to reach EDSS> or =4 outside relapse, to have sphincter or motor relapses and to reach moderate pyramidal involvement were also found to be unfavourable prognostic factors.

Visual evoked potential abnormalities in dyslexic children

Developmental reading disability (dyslexia) has traditionally been attributed to impaired linguistic skills. Recent psychophysical data suggest that dyslexia may be related to a visual perceptual deficit. A few visual evoked potential (VEP) studies have addressed this hypothesis, but their results are far from consistent. We submitted 9 dyslexic subjects and 9 age- and sex-matched normal controls to checkerboard pattern reversal VEPs. The main experimental variables were: large (0.5 cycles per degree; cpd) and small (2 cpd) checks and two reversal frequencies (2.1 Hz and 8 Hz); mean luminance and contrast (60 cd/m2 and 50%, respectively) were kept constant in all four conditions. Transient VEP (2.1 Hz) parameters did not differ between controls and dyslexics at 2 cpd. At 0.5 cpd, N70 amplitude was significantly smaller and N70 latency significantly shorter in dyslexics. Amplitudes for the fundamental frequency (8 Hz), as well as for the second and third harmonics of the steady-state VEPs were smaller in dyslexics for both stimulus sizes. A discriminant analysis correctly classified each subject. Our data confirm the hypothesis of a perceptual deficit in dyslexic subjects. The abnormalities are related to spatial and temporal stimulus frequencies: they appear when large stimuli are presented, or when the stimulation frequency is high. These data support the hypothesis of selective magnocellular dysfunction in dyslexia.

Usefulness of Bayesian graphical models for early prediction of disease progression in multiple sclerosis

Previous studies of possible prognostic indicators for multiple sclerosis have been based on "classic" Cox's proportional hazards regression model, as well as on equivalent or simpler approaches, restricting their attention to variables measured either at disease onset or at a few points during follow-up. The aim of our study was to analyse the risk of reaching secondary progression in MS patients with a relapsing-remitting initial course, using two different statistical approaches: a Cox's proportional-hazards model and a Bayesian latent-variable model with Markov chain Monte Carlo methods of computation. In comparison with a standard statistical approach, our model is advantageous because, exploiting all the information gleaned from the patient as it is gradually made available, it is capable to detect even small prognostic effects.

Serum and CSF levels of MCP-1 and IP-10 in multiple sclerosis patients with acute and stable disease and undergoing immunomodulatory therapies

The two chemokines, monocyte chemoattractant protein (MCP)-1 and gamma-interferon inducible protein (IP)-10, are thought to be involved in the pathogenesis of multiple sclerosis (MS). We measured MCP-1 and IP-10 levels in serum and CSF samples from 38 acute and 25 stable MS patients and from 40 controls. The latter consisted in patients with other inflammatory neurological diseases (OIND) or with non-inflammatory neurological diseases, and healthy controls. CSF MCP-1 levels exceeded those found in serum in all the patients studied as well as in healthy controls. CSF MCP-1 levels were significantly lower in acute MS [468+/-(S.E.M.) 18 pg/ml] than in stable MS (857+/-104 pg/ml). When detectable, serum and CSF IP-10 levels were significantly higher in acute MS (serum 331+/-66 pg/ml; CSF 118+/-16 pg/ml) than in stable MS (serum 69+/-7 pg/ml; CSF 25+/-2 pg/ml). Among OIND patients, those with HIV-1-associated dementia showed high serum and CSF levels of both MCP-1 and IP-10. Those with encephalitis showed high serum and CSF levels of IP-10 and CSF mononuclear pleiocytosis. We also evaluated the effects of 6-methylprednisolone or IFN-beta1a therapy on circulating MCP-1 and IP-10 levels. Neither MCP-1 nor IP-10 post-therapy levels varied significantly from baseline values. Our findings suggest that (a) MCP-1 could be constitutively produced within the brain; (b) MCP-1 and IP-10 CSF levels in acute MS vary significantly from those in stable MS, and these variations are inverse; and (c) current MS therapies do not modify circulating levels of MCP-1 and IP-10.

Interferon-gamma and interleukin-4-producing T cells in peripheral blood of multiple sclerosis patients

Pro- and anti-inflammatory cytokines are thought to participate in the development and regulation of autoimmunity in multiple sclerosis (MS), a demyelinating disease of the central nervous system (CNS). We analysed the percentage of interferon (IFN)-gamma and interleukin (IL)-4-producing cells in the peripheral blood of both active and stable MS patients, and of healthy controls. After short-term stimulation, cytokine-producing cells were intracellularly stained and sorted. Significantly lower percentages of IFN-gamma and IL-4-producing T cells were found in stable MS patients than in controls, and in active than in stable patients. The diminution affected CD4(+) (Th1, Th2) and CD8(+) (Tc1) phenotypes. Tc2 cells were not detected. The Th1/Th2 ratio did not differ in active and stable MS, nor in controls. The fact that Th2 and Tc1 cell percentages were higher in stable than in active MS possibly indicates that these cells play a downmodulating role in the immune response. In contrast, a role in exacerbating the immune response is not attributable to Th1 cells, given their reduction in acute MS. Our data do not support the hypothesis that MS is a Th1/Th2 paradigmatic disease; rather, they suggest that sequestration in the CNS, or activation-induced apoptosis (whether in vivo or in vitro) may explain reduced levels of IFN-gamma and IL-4-producing subsets in the peripheral blood of clinically acute patients.

Circadian and hypothermia-induced effects on visual and auditory evoked potentials in multiple sclerosis

OBJECTIVES

Body cooling has been proposed as a symptomatic treatment for multiple sclerosis. This study aimed to assess the effects of body cooling and of circadian variations on clinical parameters and on visual and auditory evoked potential measures in multiple sclerosis patients.

METHODS

Clinical status was assessed and VEPs, BAEPs and MLAEPs (all with two stimulus frequencies) were recorded a total of 4 times on two separate days (two times per day at 08:30 and 15:00 h each day) in 10 multiple sclerosis patients and 10 controls. On one of these days, the subjects were submitted to body cooling before the afternoon session.

RESULTS

Tympanic temperature was significantly higher in the afternoon. Cooling lowered the temperature by 1.4 degrees C. No clinical effects were observed. Circadian effects were detected on VEP amplitude, which increased both in controls and in patients at low stimulus frequency (P<0.01), and increased in controls and decreased in patients at high stimulus frequency (interaction: P<0.01). Cooling determined an increase in BAEP I-V peak-to-peak time in controls, and a reduction in patients at high stimulus frequency (interaction: P<0.01). In patients, cooling also determined a great increase in MLAEP amplitude (interaction: P<0.001). We did not find cooling effects on VEP measures.

CONCLUSIONS

Visual and auditory evoked potentials showed differences in circadian and cooling effects between controls and multiple sclerosis patients. These differences are consistent with the hypothesis of temperature-dependent conduction blocks in demyelinated fibers. Cooling may have a clinical effect in selected patients only.

Periodic alternating nystagmus and vestibulo-spinal system facilitating activity

OBJECTIVE

Periodic alternating nystagmus has been associated with the instability of the velocity storage mechanism, which is known to play an important role in both the vestibulo-oculomotor and the optokinetic systems. In the present study we looked for a possible spinal equivalent to PAN.

METHODS AND RESULTS

In 3 PAN patients, the H-reflex amplitude proved to be slightly but significantly influenced by nystagmus direction, in that it was greater when the nystagmus was beating toward the stimulation side.

CONCLUSIONS

This finding suggests that projections from velocity storage may play a role not only in the ocular motor but also in assisting postural stability through the vestibulo-spinal system.

Auditory saccade impairment after central thalamus lesions

Visual and auditory saccades were studied in three patients with an isolated lesion located in the central thalamus. Visual saccades proved to be normal, whereas for auditory stimuli, the amplitude of the first saccade was asymmetric: saccades ipsilateral to the lesion were significantly smaller than those directed to the contralateral side. The patients were able to make a corrective saccade and hence to improve gain and to decrease gain asymmetry. It is suggested that patients were able to localise auditory targets correctly, but did not correctly take into account eye position during the saccade, probably as a consequence of an inaccurate efference copy (corollary discharge) signal. The findings are in keeping with the hypothesis that the central thalamus deals with saccades that are based on extraretinal signals.

Opsoclonus in a patient with cerebellar dysfunction

After two days of malaise, headache, nausea, and vomiting, a 26-year-old man suddenly developed opsoclonus and stance and gait ataxia, without myoclonus. Having excluded a paraneoplastic etiology, we assumed that the disorder was probably related to a viral infection. Spontaneous resolution occurred in about two months. Opsoclonus became flutter dysmetria and then resolved. Saccadic eye movement recording disclosed the occurrence of hypermetria, increased velocity, and delayed latency, which also resolved. In this patient, the correspondence between clinical and ocular motor abnormality courses suggests a transient cerebellar dysfunction as the possible pathophysiologic mechanism for opsoclonus.

Tumor necrosis factor-alpha and its soluble receptors in plasma and cerebrospinal fluid of multiple sclerosis patients treated with methylprednisolone

Demyelination is the main pathological feature of multiple sclerosis (MS), a chronic inflammatory disease of the central nervous system. Tumor necrosis factor-alpha (TNF-alpha) can cause myelin damage and contribute to MS pathogenesis. We measured plasma and cerebrospinal fluid (CSF) levels of TNF-alpha and its soluble receptors, TNF-sRp55 and TNF-sRp75, in 18 patients with active MS, and in neurological and healthy controls. The same determinations were repeated on plasma and on CSF samples that were collected after the MS patients had ended a six-day treatment with high-dose methylprednisolone (MP). Pre- and post-treatment plasma and CSF TNF-alpha levels, when detectable, and those of TNF-sRp75, did not vary, and were similar to those of controls. CSF TNF-sRp55 levels were higher in acute MS patients than in controls. Post-treatment CSF TNF-sRp55 levels were higher than in the active phase of the disease. The MS patients, who clinically improved, tended to have the highest CSF TNF-sRp55 levels. The increase was due to intrathecal TNF-sRp55 synthesis. Although it is involved in MS pathogenesis, TNF-alpha is not detectable in plasma or in CSF samples from MS patients in various phases of the disease. A better marker of disease activity seems to be CSF TNF-sRp55 levels. The increased CSF levels of TNF-sRp55 in response to MP circumstantially suggest that this receptor could partially account for the beneficial effects of MP in acute MS.

TE671 cell-based ELISA for anti-acetylcholine receptor antibody determination in myasthenia gravis

BACKGROUND

Acetylcholine receptor (AChR) from human muscles is the antigen used currently in radioimmunoprecipitation assays (RIPAs) for the determination of anti-AChR antibodies in the diagnosis of myasthenia gravis (MG). Our aim was to develop and validate an ELISA using TE671 cells as the source of AChR.

METHODS

After TE671 cell homogenization, the crude AChR extract was used for plate coating. Anti-AChR antibodies were determined in 207 MG patients and in 77 controls.

RESULTS

The mean intra- and interassay CVs (for two samples with different anti-AChR antibody concentrations) were 9.7% and 15.7%, respectively. Test sensitivity and specificity, for generalized MG, were 79.5% (95% confidence interval, 72.8-85.0%) and 96.1% (89.0-99.1%). The detection limit was 2 nmol/L. Anti-AChR antibody concentrations from 53 MG patients, as tested with our ELISA, showed good agreement with an RIPA with a mean difference (SD) of 1.0 (5.6) nmol/L.

CONCLUSION

Our ELISA is a simple screening test for the diagnosis of MG and enables rapid and inexpensive patient follow-up.

Edge detection and surface 'filling in' as shown by texture visual evoked potentials

OBJECTIVES

We designed a stimulation paradigm that was designed to ascertain whether specific components of the texture visual evoked potentials were attributable to edge detection or to surface 'filling-in' processes.

METHODS

The stimuli were textures of parallel line elements, which were either uniform (all horizontal or vertical lines) or segregated (checkerboards in which texture line elements of neighbor checks were oriented orthogonally). A sequence of 4 stimuli, two uniform followed by two segregated stimuli, was repeated cyclically. Accordingly, segregation could appear from a uniform display; it could also be maintained, with the checkerboard illusory margin location unchanged but with alteration in the orientation of all line elements. Each stimulus was presented for 487 ms and instantly replaced by the following one.

RESULTS

Segregation-related components for segregation-appearance (Sa) and for segregation-maintenance (Sm) conditions were obtained separately by subtraction. In both conditions, a negative component was obtained with a peak latency of about 140-150 ms. However, the onset of Sa was earlier than that of Sm, whereas the respective offsets were almost identical.

CONCLUSIONS

We hypothesize that the segregation component in VEPs is composed of two subcomponents: an early part, which is related to the segregation of edges, and a final part, which is related to the 'filling-in' of the homogeneous texture surface within the boundary defined by these edges.

Amodal completion in texture visual evoked potentials

Amodal completion refers to the phenomenological finding of perceiving partly occluded objects as continuing uninterrupted behind an occluder. The outlying problem is how the visual system processes such non-local stimuli because the known processes of early vision are spatially restricted operations which segregate local differences in the visual image, and little is known about their interactions in producing the segmentation of the image into functionally coherent, or global, objects. We recorded human visual evoked potentials (VEPs) to texture stimuli and addressed local/non-local relationships in comparing a condition in which local edges were present, due to texture segregation, with a condition in which, in addition to local edges, textures appeared to continue as surfaces behind gray stripes due to non-local amodal completion. Subtraction of offset from onset responses showed: (1) a difference component due to texture segregation characterized by a negativity with onset at about 95 ms and lasting up to about 280 ms; (2) a further negativity, specifically elicited by amodal completion, with onset at about 142 ms, peaking at 175 ms, and lasting up to about 188 ms. Therefore, amodal completion occurs at an early processing stage of image analysis and the difference component in VEPs can be related to figure-ground perception.

Epidemiological study of myasthenia gravis in the province of Reggio Emilia, Italy

We carried out a retrospective incidence, prevalence and mortality survey of myasthenia gravis in the province of Reggio Emilia in Northern Italy. Based on 49 patients, the mean incidence per year for the period 1980 through 1994 was 7.8 per 1,000,000. On 31 December 1994 the prevalence rate was 117.5 per 1,000,000 for all patients, either active or recovered (50 cases in a population of 427,493) and 103.4 per 1,000,000 for the active disease. In the 15-year period 1980-1994 the average mortality rate was 1.0 per 1,000,000 per year. The average age at onset was 44.6 +/- 21.0, and the average age at the time of prevalence determination was 51.1 +/- 19.6 for the active disease. At the time of diagnosis, 21 patients (36.8%) were classed in group I according to Osserman's criteria, 31 in group II (54.4%), (19 in group II-A and 12 in group II-B), and the other 5 (8.8%) in group III. Of all the prevalence cases, 6 (12%) were in remission without therapy and 6 with therapy, while most of the others 16 (32%) were classed in group I, 15 (30%) in group II, and 1 (2%) in group III. Thymectomy was performed in 20 patients (35.1%), 12 (21%) had thymoma (malignant in 4 cases), 6 had thymic hyperplasia while in two patients thymic histology was normal. The relation the grade of Osserman's scale at the time of incidence and the presence of thymoma were significant. Higher grades of Osserman's scale were associated were malignant thymoma. Furthermore the relationship between thymectomy and the grade of Osserman's scale at the date of prevalence was significant for the presence of lower grades of Osserman's scale in the patients submitted to thymectomy.

Eye movement abnormalities in myotonic dystrophy

We studied saccade and smooth pursuit eye movements in 31 patients suffering from myotonic dystrophy (MD). On the basis of mean value comparisons, saccades were slower and hypometric and smooth pursuit eye movements performed worse in MD patients than in controls. On an individual basis, saccade duration was prolonged in 67.7%, saccades were hypometric in 19.4%, saccade latency was delayed in 9.7%, and the smooth pursuit performance index was decreased in 9.7% of patients. Eye movement abnormalities did not correlate with those detectable by visual, brain-stem auditory and somatosensory evoked potentials. We attempted to classify eye movement abnormalities as myogenic or neurogenic on the basis of differences in combination of eye movement abnormalities and the occurrence of D5/D35 dissociation; the latter consists of a prolonged duration for large (35 degrees) but not for small (5 degrees) saccades. Since D5/D35 dissociation occurred in 26/33 multiple sclerosis patients with increased saccade duration, we considered it to be a neurogenic pattern attributable to a central nervous system (CNS) dysfunction. A prolonged duration without dissociation especially in combination with saccade hypometria, is interpreted as a myogenic pattern, although the lack of dissociation may also occur with CNS impairment in case of a marked increase in saccade duration. Accordingly we classified the oculomotor abnormalities detected as neurogenic in 11 MD patients and as myogenic in another 10, but in some subjects belonging to the second group concomitant CNS impairment is not to be excluded.

Clinical aspects of fatigue in multiple sclerosis

We studied 100 multiple sclerosis outpatients in order to assess the frequency of fatigue and to detect its relationships with other clinical findings. Fatigue was quantified by fatigue severity scale (FSS; range 1-7); current clinical neurological status and disability level were respectively scored by Kurtzke's functional systems and expanded disability status scale (EDSS). FSS mean score was 4.12; fatigue was totally absent in 3% of the patients. Fatigue started before onset of the disease in 7 patients, at onset in 12 and within the first year in 7. Fatigue intensity and frequency were related to each other. FSS mean scores were significantly higher in the patients with fatigue worsened by heat (p < 0.01), with chronic progressive disease (p < 0.0001), with motor symptoms (p < 0.0001) and with EDSS > or = 3.5 (p < 0.0001). Multiple regression analysis showed a significant effect of EDSS on fatigue (p < 0.0001), not attributable to differences in duration of the disease.

Prognosis of myasthenia gravis: a retrospective study of 380 patients

The 9139 follow-up records of 438 myasthenia gravis (MG) patients were reviewed. Excluding those patients who were diagnosed 5 or more years after symptom onset (n = 37) and those who experienced only oculomotor symptoms throughout follow-up (n = 21), there were 380 patients. A survival analysis approach was used to assess the influence of prognostic factors on the following endpoints: (a) stable complete remission, (b) complete remission of at least 6 months and (c) pharmacological remission of at least 6 months. Early diagnosis was associated with a better prognosis with respect to all endpoints. Thymectomy also improved the prognosis but only for those patients without thymoma. Later MG onset was associated with a higher tendency to achieve pharmacological remission.

Soluble CD8 and ICAM-1 in serum and CSF of MS patients treated with 6-methylprednisolone

OBJECTIVE

We studied the effects of large doses of 6-methylprednisolone (6-MP) on serum and cerebrospinal fluid (CSF) soluble CD8 (sCD8) and intercellular adhesion molecule-1 (sICAM-1) levels in clinically active multiple sclerosis (MS) patients.

MATERIAL AND METHODS

Paired serum and CSF samples were from 16 patients with definite MS, treated with 6-MP (1 g daily for 6 d) during an active phase of the disease. sCD8 and sICAM-1 levels were determined with ELISA before and after the therapy.

RESULTS

Before 6-MP treatment, sCD8 levels in CSF were higher in MS patients than in patients with noninflammatory neurological disease and in healthy controls; sICAM-1 levels in serum and in CSF were higher in MS patients than in the two control groups. Ten of the 16 patients showed clinical improvement at the end of the treatment. After the therapy, serum and CSF sCD8 levels increased, whereas serum and CSF sICAM-1 levels decreased. There was no correlation between clinical improvement and laboratory parameters. We evaluated sCD8 and sICAM-1 in serum samples from 10 patients 6 months after the 6-MP treatment, when the disease was clinically silent. Neither sCD8 nor sICAM-1 levels differed from those of the control groups.

CONCLUSIONS

Our results suggest that high doses of 6-MP can influence serum and CSF sCD8 and sICAM-1 levels in active MS. At least part of the efficacy of corticosteroid treatment in MS might be ascribed to its effect both on the suppressive circuits of immune response, and on the expression of an adhesion molecule that favours lymphocyte trafficking across the blood-brain barrier.

MRI and brainstem auditory evoked potential evidence of eighth cranial nerve involvement in multiple sclerosis

An MS patient experienced sudden hearing loss. Brainstem auditory evoked potentials, previously normal, showed substantial abnormalities that suggested the impairment of the distal part of the acoustic nerve. MRI detected a small hyperintense lesion along the acoustic nerve; the lesion decreased in size and then disappeared after steroid treatment. This demonstrates that a demyelinating lesion in the distal tract of the eighth cranial nerve may cause an acute hearing loss in MS.

Antigen-specific oligoclonal IgG in AIDS-related cytomegalovirus and toxoplasma encephalitis

We retrospectively studied serum and cerebrospinal fluid (CSF) specimens from AIDS patients with either Cytomegalovirus (2 cases) or Toxoplasma gondii (5 cases) encephalitis. The samples, which had previously proved to be negative for total IgG oligoclonal bands (OCBs), were investigated for antigen-specific OCBs directed to the disease-related opportunistic agent.

MATERIAL & METHODS

Paired serum and CSF samples from the given AIDS patients were considered. We undertook affinity immunoblotting of either virus- or protozoan-specific IgG onto antigen-coated nitrocellulose paper after protein separation by agarose isoelectric focusing (IEF).

RESULTS

Antigen-specific OCBs to the disease-related opportunistic agent were detected in serum and in CSF samples from all the patients.

CONCLUSIONS

During overt AIDS, routine IEF methods may fail to detect OCBs, probably because nonspecific polyclonal hypergammaglobulinemia, which is typical of this disease, reduces their visibility. Our IEF/immunoblotting profiles are characterized by identical serum and CSF bands. The detection of antigen-specific OCBs may support the diagnosis of some opportunistic infections of the central nervous system in AIDS.

Neurological findings in the normal elderly: prevalence and relationships with memory performance

Data on the presence of neurological signs in the normal elderly are scanty, and data on their possible relationships to memory performances are not available. Three-hundred and ninety-six subjects born in 1925 and living in Pavia, who were recruited for a larger study on memory impairment in the elderly, underwent a standardized neurological examination (SNE) consisting of 22 items, an anamnestic interview and a memory test battery. A high number of signs was found, particularly for regressive reflexes (snout in 50% of cases). There was a tendency for several alterations to be found in the same subject. Accordingly, four clusters of signs were identified. Diabetes mellitus, hypertension, heart disease or past head trauma were not consistently associated with SNE scores. While memory impairment was also not consistently associated with SNE scores, there was a higher tendency for memory-impaired subjects to show at least one abnormal SNE score.

Estimating reliability of evoked potential measures from residual scores: an example using tibial SSEPs

A normative study of tibial SSEPs was performed in 74 healthy subjects, and the effects of the variables sex, age and height on SSEP parameters were assessed. In a subgroup of 20 subjects a test-retest study was also performed, which allowed us to estimate the reliability of the different parameters by means of the intraclass correlation coefficient. We demonstrated that the intraclass correlation coefficient may be biased by predictable effects of subject-related variables (such as age, height and sex), if it is computed from raw original values. This bias can be eliminated by estimating reliability indices on residual scores calculated as the differences between observed values and those predicted by subject's age, height and sex.

Saccadic and smooth pursuit eye movements in memory-impaired elderly people

The aim of the study was to compare eye movements recorded in 14 non-demented memory impaired elderly subjects with those of 36 sex- and education-matched controls. Eye movements were recorded with the bitemporal electrooculographic technique, and analyzed with a personal computer. Saccades were elicited in accordance with reflexive, predictive and antisaccade paradigms. Smooth pursuit eye movements were elicited with a triangular ramp paradigm. The memory-impaired subjects showed a higher prevalence of increased reflexive saccade latency and a lower smooth pursuit performance index. In addition, we detected a correlation between antisaccade and reflexive saccade latencies. Our results showed very slight differences in eye movement parameters. However, our findings are in keeping with the hypothesis of a subtle involvement of differing cortical areas in memory impaired subjects.

Recovery functions of early cortical median nerve SSEP components: normative data

The recovery functions of parietal P14-N20, N20-P27 and frontal P22-N30 amplitudes were assessed in 17 healthy controls aged 20-50 years by means of the paired stimulus technique. One unpaired and 4 paired stimuli with interstimulus intervals (ISIs) of 25, 50, 75 and 100 msec were cyclically presented in a single run. Responses to the unpaired stimulus were subtracted off-line from paired stimulus responses. The highest suppression was reached at shorter ISIs for components with shorter latencies. The mean suppression of P22-N30 was influenced by the subject's age, being greater in younger subjects. Normative data are reported.

Pavia memory project: study design and first results

This paper describes the design and first results of the cross-sectional phase of a study on memory impairment in elderly subjects (Pavia Memory Project). The target population consisted of the 1,046 subjects born in 1925 and currently living in Pavia. Four hundred and thirty-six subjects (plus 287 interviewed at home) participated in the first stage, which consisted of a semi-structured anamnestic interview. The 400 interviewed subjects with none of the exclusion criteria participated in the second stage, which consisted of a memory test battery, a standardized neurological examination and screening procedures for depression (GDS) and dementia (MMSE). On the basis of the memory scores, three groups were defined: memory impairment (MI: 8.8%), mild memory impairment (MMI: 39.8%); normal (N: 51.3%). There were more failures on the visuo-spatial memory tests. Depression was equally distributed in the N and MI groups (about 15%), but was more frequent in the MMI group (27%). Abnormal neurological signs were largely independent of memory performance. Two cohorts (of MI and N subjects) underwent neuropsychological and instrumental (CT-scan, EEG, ERPs, eye movements) assessment, which will be regularly repeated in the longitudinal phase.

HLA complement gene polymorphisms in multiple sclerosis. A study on 80 Italian patients

We studied C4A, C4B, and Bf complement gene polymorphisms in 80 Italian patients with multiple sclerosis (MS). We observed a significantly higher frequency of C4AQ0 allele in patients with the relapsing-remitting form of MS than in ethnically homogeneous controls. Restriction fragment length polymorphism analysis by Southern blotting of the C4/CYP21 gene complex showed that a structural gene deletion was present in 45% of patients with the C4AQ0 allele. Our data support the hypothesis that relapsing-remitting MS and primarily chronic progressive MS are immunogenetically distinct diseases; further, complement factor abnormalities typical of autoimmune diseases could influence the pathogenesis of MS.

Usefulness of trigeminal somatosensory evoked potentials to detect subclinical trigeminal impairment in multiple sclerosis patients

Trigeminal somatosensory evoked potentials (TSEPs) by surface electric pulse stimulation were recorded in 30 normal subjects and in 70 multiple sclerosis (MS) patients, 13 of whom presenting clinical trigeminal impairment. We observed significant prolongation of all TSEPs parameters in MS group. TSEPs were abnormal in 45 patients (64.3%). Clinical and neurophysiological data agreed in 36 patients (51%) on 84 sides (60%). TSEPs were able to detect clinically silent lesions 54 times. TSEPs recording proves to be an additional useful test in MS multimodal evoked potential protocols.

Eye movement quantitative evaluation before and after high-dose 6-methylprednisolone in multiple sclerosis

We studied saccadic and smooth pursuit eye movements in 24 patients suffering from multiple sclerosis during disease worsening, before and after high-dose 6-methylprednisolone infusions. Quantitative evaluation of saccades was based on amplitude/duration and amplitude/peak velocity relationships, precision (i.e. the ratio of actual to desired saccade amplitude) and the latency, whereas smooth pursuit eye movements were studied using target velocity/performance index relationship. At basal recordings, 22/24 (91.7%) of the patients showed at lest one abnormality. Eleven of the 24 patients (45.8%) showed modification of one or several parameters: improvement in 6 patients, worsening in 2, coexistence of both trends in 3. Latency improvement was the only significant modification when patients were considered as a group. Neurophysiological modifications did not correspond to clinical changes.

Sensitivities and predictive values of paraclinical tests for diagnosing multiple sclerosis

The sensitivities and predictive values of visual, somatosensory, and brain auditory evoked potentials (EPs), cerebrospinal fluid oligoclonal banding (CSF-OB) and magnetic resonance imaging (MRI) were evaluated for the early diagnosis of clinically definite multiple sclerosis (CDMS). Paraclinical evidence of asymptomatic lesions allows a diagnosis of CDMS. Eighty-two patients in whom MS was suspected but diagnosis of CDMS was not possible entered the study prospectively. Paraclinical examinations were performed at entry. Patients were examined and underwent EPs every 6 months, and MRI yearly. After a mean follow-up of 2.9 years, 28 patients (34%) had developed CDMS (McDonald-Halliday criteria). The initial MRI was strongly suggestive of MS in 19 of these (68%), while 27 (96%) had at least one MS-like abnormality in the initial MRI. CSF-OB and EPs had lower sensitivities. CDMS developed during follow-up in 19 of the 36 patients (53%) who had an initial MRI strongly suggestive of MS but in only 1 of the 25 who had normal MRI when first studied. These results support previous conclusions that MRI is the most sensitive test for detecting white matter asymptomatic lesions, and the most predictive for the diagnosis of CDMS.

Lack of both spinal fluid oligoclonal bands and complement 4A protein in an MS patient

We report the case of a multiple sclerosis (MS) patient without oligoclonal bands (OCB) in three cerebrospinal fluid samples. Restriction fragment length polymorphism analysis of Class 3 genes with radiolabelled specific cDNA probes showed a homozygous deletion of the complement 4A (C4A) genes. Consequent lack of C4A protein can alter the development of humoral immune response probably preventing OCB production. Our observation may suggest a link between a rare immunogenetic pattern and the absence of OCB in MS.