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Using surface electrodes, sensory nerve action potentials (SAP) have been recorded in the proximal segment (mid-calf to lateral malleolus) and the distal segment (lateral malleolus to toe 5) of the sural nerve and in the median nerve in 79 control subjects. The values obtained for the distal segment of the sural nerve varied widely and in seven apparently normal subjects no SAP could be distinguished. In the proximal segment conduction velocities were over 40 m/s and there was no significant change with age, unlike the median nerve in which a highly significant slowing occurred with age. Comparison of the results of sural and median sensory conduction studies in 300 consecutive patients screened for sensory polyneuropathy confirms the value of sural nerve sensory studies as a routine screening test, and confirms the belief that the changes in polyneuropathy are usually more prominent in lower limb nerves. It is therefore suggested that studies of sural sensory conduction form the single most useful test in the diagnosis of sensory polyneuropathy. [ABSTRACT FROM AUTHOR]

A disease consisting of persistent muscle cramps involving distal muscle groups that occurred in 12 members of the same family is described. The cramps appeared on exertion and in full relaxation or during sleep. In the third generation they appeared in the second decade; in the fourth and fifth generations in childhood with higher frequency and intensity of cramps. The disease is not sex linked and seems to be dominantly inherited. Electromyography showed no myotonic response on insertion. Motor unit potentials were normal. Continual waxing and waning electrical discharges corresponding to clinically visible contractions of parts of the muscles were present. Repetitive nerve stimulation caused no change in the amplitude of evoked muscle potentials. On spinal anaesthesia or nerve block the muscle contractions continued but became painless. The movements were only stopped with local infiltration of anaesthetic into the muscle. There were no cramps on ischaemic work. Drug studies revealed no benefit on carbamazepine, slight relief with meprobamate, and complete disappearance with potassium chloride. The remission outlasted the treatment for three months and then cramps of milder degree reappeared. Repeated potassium chloride treatment was not effective. The cramps increased on hydrochlorothiazide, and 12 hours after spinal anaesthesia. In the authors' opinion the disease should be considered as not belonging to any known nosological entity. [ABSTRACT FROM AUTHOR]

A study has been made of the isometric twitches of single motor units in the extensor hallucis brevis (EHB) muscle in man. The twitch contraction times ranged from 35 to 98 msec and the pooled results indicated the presence of at least two types of unit. The recorded twitch tensions also varied considerably (from 2 to 14 g) but were not related to the twitch speeds. The twitch tension developed by the whole EHB muscle depended on the initial length of the muscle and on the age of the subject. The EHB muscle was estimated to contain approximately 56 motor units. [ABSTRACT FROM AUTHOR]

Within a group of 23 patients who presented with status epilepticus a syndrome is defined in which sudden unheralded status occurs in apparently healthy individuals. Recovery from the attack is complete and no other evidence of cerebral pathology may be found at the time. In seven of nine such cases studied the final diagnosis at follow-up, either by necropsy or by operation, was of cerebral tumour. In five of the seven the fronto-temporal region was the site of pathology. It is suggested that the occurrence of isolated status indicates a possible cerebral tumour for which careful search should be made and, if negative, follow-up study arranged. Of 20 of our patients with status epilepticus in whom the site of lesion was definite, nine were exclusively frontal and a further six had some frontal involvement. This confirms previous evidence that symptomatic status epilepticus indicates a frontal lesion. [ABSTRACT FROM AUTHOR]