Brain : a journal of neurology
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Electromyographic (EMG) flexor muscle responses evoked by electrical stimulation of ipsilateral peripheral nerves were studied in 16 patients with clinically complete spinal cord transection. Stimuli were applied either to a cutaneous nerve (sural) or to a mixed nerve (tibial) and muscle responses were recorded from tibialis anterior, biceps femoris and rectus femoris. EMG recordings after both sural and tibial nerve stimulation showed that distinct early and late ipsilateral flexor muscle responses could be elicited. ⋯ The low threshold of the late reflex corresponded to the excitation of relatively rapidly conducting afferents and its central spinal delay was more than 100 ms. The late reflexes were compared with those described by Andén et al. (1964) in the acute spinal cat injected with DOPA and were found to have similar characteristics. The mechanism for the increase in latency of the late response is discussed in relation to the interpretation of Lundberg (1979).
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Von Hippel-Lindau disease is an autosomal dominant multisystem disorder, the commonest presenting manifestations of which are haemangioblastomas of the cerebellum and retina. Affected individuals are at risk of developing a number of other lesions, the most serious of which are renal carcinoma, haemangioblastomas elsewhere in the central nervous system and phaeochromocytoma. Patients with this disease can therefore present to a number of disciplines during their lifetime and unless the possibility of von Hippel-Lindau disease is considered, the patient may wrongly be assumed to have an isolated lesion. ⋯ Clinically significant manifestations almost invariably developed before the age of 50 years. Limited screening of our index cases and their at-risk relatives demonstrated one asymptomatic renal carcinoma. We propose a protocol for screening all individuals at risk of von Hippel-Lindau disease, which involves annual retinal examination from five years, and biennial computerized tomography of the head and abdomen from fifteen and twenty years, respectively.
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The definition of causalgia as a pain state following peripheral nerve injury has been accepted since the term was introduced by Weir Mitchell over a century ago. In the present paper, problems of nomenclature and nosology are discussed, and attention is drawn to the fact that the same clinical features can occur spontaneously, in nontraumatic nerve lesions, in the absence of a part as in phantom limb states, and in diseases confined to the central nervous system. Attention is also drawn to the lack of correlation of pain with the effects mediated by catecholamines in the sympathetic nervous system and with the response to sympathetic blockade. ⋯ Certain authors in the past considered that the central nervous system (CNS) played an important part in causalgia, and current evidence supporting this view is assessed. Involvement of the CNS is suggested by the development of causalgia in diseases confined to the CNS and in phantom pain states; the unusual distribution of pain sometimes experienced; the paradoxical development of widespread pain that can occur after damage to the sympathetic nervous system; the effects of peripheral sympathetic blockade even when the cause lies centrally; and central interactions with motor, sensory and psychological phenomena. Reservations concerning the role of catecholamines in causalgia are outlined, and the possibility is considered that nonadrenergic substances may be implicated.
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Somatosensory evoked potentials (SEPs) following median, ulnar and tibial nerve stimulation were recorded from sites over the shoulders, neck and scalp in 34 patients with cervical spondylosis. Twenty control subjects were matched for sex and age. Detailed clinical and radiological data were assembled, with particular attention to the sensory modalities impaired and the locus and severity of cord compression. ⋯ The correlation of SEP findings with radiological data was generally poor. SEP abnormalities were detected in 6 out of 8 patients with clinical myelopathy but no radiological evidence of posterior cord compression, suggesting that impairment of the blood supply may be an important factor contributing to cord damage. An application for SEPs in the clinical management of cervical spondylosis may lie in the detection of posterior column involvement and the differential diagnosis from disorders such as multiple sclerosis and amyotrophic lateral sclerosis.
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The nociceptive flexion reflex (RIII reflex) and the concurrent subjective pain score elicited by right sural nerve stimulation at random intensities were studied in 10 healthy volunteers. A close relationship was found between the recruitment curves of the reflex and the pain score as a function of stimulus intensity. As a consequence, the threshold of the RIII reflex (Tr) and of pain sensation (Tp) were found to be almost identical (mean: 9.8 and 11.3 mA, respectively). ⋯ This indicates a close relationship between the effects of the conditioning nociceptive stimuli on the reflex and the related pain sensation. These results suggest that the modulation of pain by heterotopic nociceptive stimuli can be explained at least in part by a depression in the transmission of nociceptive messages at the spinal level. They are discussed with reference to the counterirritation phenomena and common features with 'diffuse noxious inhibitory controls' (DNIC) are underlined.