Criteria For MS Research Articles

New Diagnostic Criteria for MS Issued

New Diagnostic Criteria for MS Issued

New Diagnostic Criteria for MS Issued

New Diagnostic Criteria for MS Issued

Multisequence MRI in clinically isolated syndromes and the early development of MS.

To apply multisequence MRI techniques to patients with clinically isolated syndromes, to document the pattern and frequency of abnormalities at baseline and early follow-up, and to determine their predictive values for the early development of clinical MS. Disseminated lesions on T2-weighted brain MRI confer an increased risk of progression to clinically definite MS. Newer MRI techniques increase detection of lesions in both brain and spinal cord, and clarify further their pathology. The predictive value of such techniques for the development of clinical MS needs to be defined. Brain and spinal MRI were performed on 60 patients after their first demyelinating event. A total of 50 patients were followed for 1 year, and 49 underwent repeat brain MRI 3 months after the initial scan. At baseline, 73% of patients had lesions on T2-weighted fast spin-echo (FSE) brain images and 42% had asymptomatic spinal cord lesions. Fast fluid-attenuated inversion-recovery brain did not improve detection of brain lesions. Repeat brain MRI demonstrated new FSE lesions in 43% of patients. After 1 year, 26% of patients developed MS. The MRI features that provided the best combination of sensitivity and specificity for the development of MS were the presence of new FSE lesions at follow-up and enhancing lesions at baseline. The frequency of developing clinical MS was higher for those with both brain and spinal cord lesions at baseline (48%) than brain lesions alone (18%). The combination of baseline MRI abnormalities and new lesions at follow-up, indicating dissemination in space and time, was associated with a high sensitivity and specificity for the early development of clinical MS. These data suggest a potential role for new diagnostic criteria for MS based on early MRI activity. Such criteria may be useful in selecting patients for therapeutic trials at this early clinical stage.

Multiple sclerosis in children under 6 years of age.

To characterize MS patients with the earliest onset of disease. MS-primarily a disease of young adulthood-begins in childhood in 3 to 5% of cases. However, onset before 10 years of age is considered exceptional. Accordingly, inclusion age at onset is generally between 10 and 59 years. Information was obtained on patients with MS treated at our institution (n = 6) or from reports in Medline or bibliographies. Onset of disease was before 6 years of age, for a total of 49 patients (29 girls, 20 boys). All patients had clinically defined MS according to Poser's criteria; 22 were also laboratory supported. The female/male ratio (1.4) was lower than that usually recorded for adult onset MS (2.0) and that of MS with onset between 6 and 15 years (2.2 to 3.0). The group of patients (n = 5) with onset before 24 months of age showed the lowest ratio (0.6) and carried the most unfavorable prognosis. Among initial symptoms, ataxia was preponderant (61%). Optic nerve involvement became more frequent with age. Generalized or partial seizures occurred in 22% of cases. First inter-attack interval was less than 1 year in 63% of the cases. The yearly relapse rate ranged from 1.1 at disease onset to 0.2 after 9 years from disease onset. At follow-up (mean length 6.8 years), the disease was relapsing-remitting in 84% patients and the grade of recovery was complete in 64%. Definite MS can be consistently diagnosed by current criteria for adult onset MS in patients with the earliest onset of disease who show peculiar clinical features and natural history. These findings may suggest a reconsideration of current lower limits for MS diagnostic criteria.

Optic neuritis as onset manifestation of multiple sclerosis: a nationwide, long-term survey.

To determine the predictive value on survival of optic neuritis (ON) as onset manifestation of MS. We used data obtained from the Danish Multiple Sclerosis Registry, which includes virtually all patients diagnosed with MS in Denmark. From 1949 to 1990, 7,548 unselected patients fulfilling standardized diagnostic criteria of MS were registered. The onset manifestation of MS was known in 6,923 patients, and was ON in 1,282 patients (19%). The mean age at onset was 31.1 years for these patients compared with 34.8 years for patients with another or unknown onset manifestation of MS (non-ON) (p < 0.001). The mean delay from the first known manifestation of MS to the final diagnosis of MS was 6.1 years (ON) and 4.2 years (non-ON). The median survival time from onset of ON was 30 years in men (compared with 41 years in the matched general male population) and 40 years in women (versus 47 years). The excess death rate increased with age at onset of MS in people of each sex. Excess death rate for women differed significantly between patients with ON as onset manifestation and patients with another or unknown onset manifestation of MS (8.3 versus 13.0). In patients with ON as onset manifestation of MS, the excess death rate was significantly higher in men (14.0) than in women (8.3). ON as onset manifestation of MS indicates a more favorable prognosis of survival of MS judged by excess death rate only in women.

Predictive Value of Late Potentials after Myocardial Infarction in the Thrombolytic Era

Background: The value of the signal‐averaged electrocardiogram (ECG) for prediction of arrhythmic events (AE) after myocardial infarction (MI) has been well established. The current incidence of AE in the first year after Ml is remarkably lower than that reported in the 1980s. In this study, we compared the prevalence and the predictive value of late potentials (LP) in patients with Ml treated with either conventional or reperfusion therapy.Methods: A total of 433 patients (age 62 ± 10 years, 350 men) recovering from acute Ml were prospectively analyzed. Two hundred seven patients had conventional therapy (group A), and 226 had reperfusion therapy (group B) within 12 hours of the onset of symptoms: 145 of group B patients received thrombolytic agents, whereas 81 underwent direct or rescue angioplasty. Standard signal‐averaged variables were recorded (filter range 40–250 Hz) 10 ± 6 days (range 5–30 days) after Ml. LP were defined as being present if 2 of the following were met: fQRS &lt;114 ms, RMS40 20 μV, LAS40 &lt;38 ms (criterion 1), and if QRS 120 ms (criterion 2).Results: LP were found in 33% versus 21%, P = 0.004 (criterion 1) and in 13% versus 8%, P = 0.057 (criterion 2) of group A and group B patients, respectively. During a mean follow‐up of 24 ± 19 months (range 5 days to 48 months), there were 22 AE (5%). The AE rate for patients with conventional therapy was significantly higher in those with LP than in those without LP: 12% versus 4%; P = 0.03 (criterion 1) and 30% versus 3%; P = 0.00003 (criterion 2). The AE rate for patients with reperfusion therapy was similar in patients with and without LP: 9% versus 3%, P = 0.09 (criterion 1) and 12% versus 3%, P = 0.14 (criterion 2). Multivariate analysis indicated that the presence of LP based on criterion 2 was the strongest independent predictor of AE in patients with Ml treated with conventional therapy.Conclusion: In this study, reperfusion therapy influenced the prevalence of LP. The predictive value of LP for serious AE in the postinfarction period was remarkably affected by thrombolysis and/or interventional catheter therapy.

The mechanisms of shallow earthquakes and the monitoring of a comprehensive test ban

The ability of seismological criteria to identify earthquakes from underground explosions depends partly on the orientation of the earthquake source. Well-determined double-couple moment tensor solutions for a large number of earthquakes have been published in the Harvard centroid moment tensor (CMT) and United Slates Geological Survey (USGS) catalogues. Statistical analyses of these catalogues indicate that the distribution of the orientation of earthquake mechanisms is not random. The distribution of the T axes shows significant clustering around the downward vertical, indicating that a larger number of earthquake mechanisms radiate compressional P-wave energy to teleseismic distances from near the maximum of the radiation pattern than is predicted if earthquake sources are randomly oriented double couples. The clustered T axes correspond to compressional dip-slip mechanisms, and it is this type of mechanism which is believed to cause both the mb: Ms (the ratio of body-wave to surface-wave magnitude) and first-motion criteria to misidentify an earthquake as an explosion.

Practical problems in the organisation of clinical trials in multiple sclerosis.

The problems of organising clinical trials in MS include the general aspects relating to clinical trials in any discipline but extend also to specific problems arising in the assessment of a relapsing remitting condition. These factors relating to the clinical characteristics of the disease, the diagnosis, the selection of patients and the methods of clinical and laboratory assessment are described and discussed. Suggestions are made for the use of internationally accepted diagnostic criteria for MS and a review is made of the other recognised problems in this field.

The seismic disturbance of 1976 March 20, elast Kazakhstan: earthquake or explosions?

On 1976 March 20 a seismic disturbance took place near an explosion test-site in East Kazakhstan, USSR: on the mb:Ms criterion this disturbance is identified as an earthquake. However, it has been suggested that the source may have been one or more explosions. It is shown here that the polarities and relative amplitudes of the main arrivals on the short-period P-wave seismograms of the disturbance can be accounted for by assuming the source was an earthquake in a crust with some lateral variation in structure. There is no evidence that the disturbance was anything other than a single earthquake.

Multivariate autoregressive representation of seismic P-wave signals with application to short-period discrimination

abstract It is shown that seismic P-wave vector signals as recorded by selected NORSAR subarrays can be described by multivariate parametric models of autoregressive type. These are models having the form X ¯ ( t ) − A 1 X ¯ ( t − 1 ) − ... − A p X ¯ ( t − p ) = W ¯ ( t ) Where X¯(t) (t) is the digitized short-period vector time series defined by the P-wave signal and W¯(t) (t) is a white noise vector time series. The multivariate autoregressive analysis is undertaken for 83 nuclear explosions and 72 earthquakes from Eurasia. For each event a separate analysis of the main signal and of the coda has been carried through. It is found that in most cases a reasonable statistical fit is obtained using a low-order autoregressive model. The autoregressive parameters characterize the spectral density matrix of the P-wave signal and therefore form a convenient basis for constructing short-period discriminants between earthquakes and explosions. Based on the classification results for our data base of Eurasian events, we find that the multivariate autoregressive parameters have a substantially larger discrimination potential than the short-period parameters suggested earlier in the literature. In fact our results indicate that, based on autoregressive parameters, it may now be possible to construct purely short-period discriminants which are comparable, if not superior, to the mb:Ms criterion.

An improved discriminant for test ban verification using short and long period spectral parameters

Spectral estimates for Rayleigh and Love waves have been combined with autoregressive parameters for P‐waves and used for discriminating between nuclear explosions and earthquakes in Eurasia. Obtained results using NORSAR data indicate that this new discriminant is superior to the conventional mb∶Ms criterion.