Brain : a journal of neurology
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Comparative Study
The role of NMR imaging in the assessment of multiple sclerosis and isolated neurological lesions. A quantitative study.
The form and distribution of MRI abnormalities in 114 patients with clinically definite multiple sclerosis (MS) have been compared with observations on 53 apparently healthy individuals, 129 patients with isolated focal neurological lesions with which MS often presents (51 patients with optic neuritis, 44 with isolated brainstem lesions and 34 with isolated spinal cord syndromes) and 105 patients with disorders which may be confused clinically or radiologically with MS. The latter comprised 55 patients with cerebral vascular disease (including 7 cases of dementia with diffuse white matter disease), 24 with degenerative ataxic disorders, 8 with cerebellar tonsillar ectopia, 7 with sarcoidosis and 11 with a variety of other disorders. Periventricular abnormalities were found in all but 2 patients with MS and discrete white matter lesions in all but 12. ⋯ There were quantitative differences in T1 and T2 between the normal appearing white matter in MS and normal brain. Studies of postmortem brains provided convincing evidence that the MRI abnormalities in MS correspond with plaques. Evidence is adduced to support the view that an important source of the abnormal NMR signals in acute lesions is oedema, and in chronic lesions is gliosis; demyelination per se is unlikely to make an important contribution.
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Comparative Study
An electrophysiological investigation into the pain-relieving effects of heterotopic nociceptive stimuli. Probable involvement of a supraspinal loop.
It has previously been shown that, in normal subjects, heterotopic painful stimuli induce parallel decreases in the sensation of pain and the nociceptive spinal flexion reflex RIII simultaneously evoked by electrical stimulation of the sural nerve. By contrast, heterotopic non-noxious stimuli were ineffective in this respect. In order to assess the possible involvement of supraspinal structures in these changes, we have now compared the effects of nociceptive electrical stimuli applied to the fourth and fifth fingers of the hand on the contralateral RIII reflex in 5 normal subjects and 5 tetraplegic patients suffering from a clinically complete spinal cord transection of traumatic origin. ⋯ These results show that the effects of heterotopic nociceptive stimulation observed in normal man are possibly mediated by a complex loop involving supraspinal structures. This further underlines the similarity between this phenomenon and the Diffuse Noxious Inhibitory Controls (DNIC) described in the rat, since the latter are observed in intact but not in spinal animals. These findings are discussed with reference to counter-irritation phenomena and procedures aimed at producing analgesia by somatic electrical stimulation.