Motor and somatosensory evoked potentials in hereditary spastic paraplegia.

Motor evoked potentials (MEPs) from the arms and legs to transcranial stimulation of the motor cortex and somatosensory evoked potentials (SSEPs) from stimulation of the nerves of the arms and legs, were recorded in 11 patients with hereditary spastic paraplegia. Electrophysiological abnormalities were found to be distributed differently among the systems examined; the longer the pathway, the higher the incidence and severity of impairment. MEPs from the leg were either absent or clearly reduced or prolonged in all patients. Eight patients showed abnormal cortical SSEPs on stimulation of the leg (absent or reduced responses in four, slowed central conduction velocity in seven), but only two of these patients had abnormal MEPs from the arm (absent responses). Cortical SSEPs on stimulation of the median nerve were reduced in two patients. Mean values of amplitude and central conduction velocity for MEPs and SSEPs from the leg were significantly different between patients and controls. Such differences were not found for either MEPs or SSEPs from the arm. This distribution of abnormalities, which suggests a differential involvement of the spinal pathways, parallels the reported pathological pattern in which degeneration of axons is more common and severe in the motor and sensory fibres supplying the leg.     

A prospective audit of the use and costs of myelography in a regional neuroscience unit.

A consecutive series of 397 myelograms performed in 385 patients over a six month period at the Mersey Regional Neurosciences Unit is reported. The reasons for performing the myelogram were to identify the cause of a radicular lesion in 54% of patients, a chronic spinal cord lesion in 30%, an acute cord lesion in 9%, suspected disease at the level of the foramen magnum 6%, and for a variety of other conditions in 8%. For the 385 patients undergoing a myelogram in the study period, the median interval from admission to request, request to myelography and from myelography to discharge was nought, one and three days respectively. The proportion of patients submitted to myelography by individual consultants ranged from 7% to 28%. There was a two-fold variation in the delays in the time to requesting and performing myelograms. There was room for improvement in the clinical information supplied on the myelography request form. The role of ancillary investigations and their effect on myelography was unclear. Only 16 of the patients with suspected cord disease had visual evoked responses performed before myelography. Five of them had myelography after an abnormal result. The estimated annual direct cost of myelography in the unit was at least 486,000 pounds. Reorganisation might have yielded hypothetical "savings" of between 30,000 pounds (6%) and 155,000 pounds (32%), though in practical terms these "savings" represented resources which might have been freed for use in other higher priority clinical problems within the unit, rather than true reductions in monetary cost.     

Working conditions and health behavior as causes of educational inequalities in self-rated health: an inverse odds weighting approach

Objective:Using a novel mediation method that presents unbiased results even in the presence of exposure–mediator interactions, this study estimated the extent to which working conditions and health behaviors contribute to educational inequalities in self-rated health in the workforce.Methods:Respondents of the longitudinal Survey of Health, Ageing, and Retirement in Europe (SHARE) in 16 countries were selected, aged 50–64 years, in paid employment at baseline and with information on education and self-rated health (N=15 028). Education, health behaviors [including body mass index (BMI)] and working conditions were measured at baseline and self-rated health at baseline and two-year follow-up. Causal mediation analysis with inverse odds weighting was used to estimate the total effect of education on self-rated health, decomposed into a natural direct effect (NDE) and natural indirect effect (NIE).Results:Lower educated workers were more likely to perceive their health as poor than higher educated workers [relative risk (RR) 1.48, 95% confidence interval (CI) 1.37–1.60]. They were also more likely to have unfavorable working conditions and unhealthy behaviors, except for alcohol consumption. When all working conditions were included, the remaining NDE was RR 1.30 (95% CI 1.15–1.44). When BMI and health behaviors were included, the remaining NDE was RR 1.40 (95% CI 1.27–1.54). Working conditions explained 38% and health behaviors and BMI explained 16% of educational inequalities in health. Including all mediators explained 64% of educational inequalities in self-rated health.Conclusions:Working conditions and health behaviors explain over half of the educational inequalities in self-rated health. To reduce health inequalities, improving working conditions seems to be more important than introducing health promotion programs in the workforce.     

Assessing relapses in treatment trials of relapsing and remitting multiple sclerosis: can we do better?

Published Phase III immunomodulatory treatment trials in relapsing and remitting multiple sclerosis have demonstrated a modest decline in attack rates, but only a minor effect on disability. As genuine disability progression is difficult to ascertain in relatively short studies with the conventional rating scales available, the acquisition and analysis of relapse data are critical. However, there are as yet unresolved questions related to the latter. We will first discuss the problems associated with relapse definitions by trial investigators, the paucity of the data collected (especially on the magnitude and duration of exacerbations) and statistical issues in their analysis. We will then suggest practical points for obtaining more accurate information on relapses and evaluating them meaningfully. While there is still general consensus among neurologists that primary endpoints for therapeutic trials should be clinical, improvements for future protocols are essential.     

Interferon beta-1a in relapsing-remitting multiple sclerosis.

The accumulated results from multiple trials have unequivocally demonstrated beneficial effects of interferon beta-1a on disease activity in relapsing-remitting multiple sclerosis, both for clinical and magnetic resonance endpoints. New data suggest that low doses administered once weekly are relatively ineffective and that higher, more frequent doses are required for optimal benefit.