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A 67-year-old male patient with Waldenstrom's macroglobulinaemia associated with a sensorimotor polyneuropathy is reported. The progress of the disease was well controlled by Chlorambucil therapy. The sural nerve biopsy showed, in addition to loss of myelinated fibres an amorphous hyalin-like substance in the perineurium, endoneurium and the blood vessel walls which was strongly positive with the periodic acid-Schiff stain. Immunofluorescent study revealed that this substance contained IgM. Electron-microscopically this substance was shown to be osmiophilic and granulated. There was no deposit of amyloid in the sural nerve by Congo red and thioflavin T methods. However, cytoplasmic fibrils of about 80 A in thickness were present in the endothelia and pericytes. The pathogenesis of macroglobulinaemic polyneuropathy is discussed with special emphasis on a possible antibody activity of abnormal monoclonal IgM against the peripheral nervous system.

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.

Numerous procedures have been proposed for the correction of symptomatic subclavian artery occlusive disease, none of which have been uniformly accepted by vascular surgeons. During the past 21 months we have successfully treated six patients with symptomatic subclavian artery occlusive disease by the construction of an axillary-axillary artery bypass. There were three complications in this small series, a wound hematoma, a case of median nerve parasthesias, and a late graft thrombosis, possibly caused by external pressure on the graft. These complications have not caused any serious morbidity. All patients have been followed to the present time, all have experienced symptomatic improvement and none has developed any symptoms of donor arm ischemia. Axillary-axillary artery bypass is currently our procedure of choice for the correction of symptomatic subclavian artery occlusive disease because of its effectiveness, absence of serious morbidity and ease of performance.

Estimates of the number of motor units in extensor digitorum brevis (EDB) and in the thenar muscles were made electrophysiologically in a group of 66 diabetic subjects. Loss of motor units was common in those with no clinical evidence of neuropathy and was most severe in EDB. The clinical form of the neuropathy was a poor guide to the severity of EDB or thenar motor unit loss. Motor unit losses in diabetics 60 years of age or over did not differ from those found in many control subjects of equivalent age. The finding of motor unit loss, abnormal digital sensory potentials and motor conduction velocity slowing in diabetics without a neuropathy and in unaffected limbs of those with a neuropathy, pointed to a general metabolic disturbance of diabetic peripheral nerves. This may have made diabetic nerves more liable to nerve entrapment and probably accounted for the large number of subjects with local neuropathies, particularly of the median nerve in the region of the carpal tunnel.

This paper investigates the human evoked response produced by peripherally stimulating the median nerve with a repetitive high frequency stimulus. The human somatosensory system can be driven and the resultant evoked response can be consistently recognized at frequencies as high as 200 Hz. This somatosensory evoked response to trains (SERT) has proven to be a very reliable and easily quantifiable measure. Seventeen normal subjects and a total of 28 hands were investigated. Each hand was stimulated with eight different frequency runs, each consisting of 64 trains of stimuli spaced 2 sec apart. The frequencies of stimulation were 12, 20,40,60,80,100,160 and 200 Hz. Each stimulus had a width of 0.25 msec and the train lenght was fixed at 250 msec. Three data processing steps were utilized. The initial procedure was the on-line computation of the contralateral SERT. Secondly, a filtered SERT was calculated by narrowband filtering of the EEG signal and averaging. Finally, a single cycle filtered SERT was calculated by narrowband filtering of the EEG signal and averaging across the interstimulus interval. The amplitude and time of occurence of the peak negative value obtained from this measure were used to quantify the suject response at each stimulating frequency. Signal variability due to activity at the bipolar reference electrode was investigated, as were differential phase shifts between signals recorded at anterior and posterior electrode locations. In addition, topographical mappings of the single cycle amplitudes and phase angles were obtained at the different stimulating frequencies. The distributions of the peak-to-peak amplitude values were consistent with topographical data previously reported for the somatosensory evoked response, while the phase angles tended to distribute in such a way as to divide the scalp into two discrete regions.

Displaced extension supracondylar fractures of the elbow 1. One hundred and ten children were treated by reduction and stabilisation by two pins inserted laterally at an angle of 30 degrees to one another. 2. The complications before and after treatment included fifteen nerve lesions in thirteen patients. The ulnar nerve was involved on one occasion only. Solitary radial nerve injuries occurred with postero-medial displacement of the distal fragment, while median nerve and brachial artery injuries were associated with postero-lateral displacement. All the lesions recovered spontaneously. 3. There were no ischaemic complications after treatment, despite the ligation of one ruptured brachial artery. 4. The average stay in hospital was four days, compared with twenty days for thirty-two other patients treated in traction because of gross oedema. 5. Of eighty patients seen six months to five years after the fracture, seventy (or 87·5 per cent) had excellent or good results, seven patients with marked varus deformities had fair results, and two patients had poor results with very stiff elbows. Displaced flexion fractures 1. The clinical features, complications and treatment of seventeen cases are described. 2. There were no complications involving the median or radial nerves or the brachial artery, but three patients had a lesion of the ulnar nerve. 3. Nine children had closed reduction and fixation by two lateral percutaneous pins. 4. Reduction was difficult and the results poor compared with extension fractures. Closed reduction failed in one-third of the children, and the functional and cosmetic results were unsatisfactory in over half the patients reviewed.

Mature mouse and cat peripheral nerve fibers have been examined in vitro by time-lapse photography. Some Schmidt-Lanterman clefts which were open at the start closed later; other were seen to open and then to close, some of them more than once. The implications of these movements are considered, especially in regard to the question of the passage of materials from the endoneurial connective tissue spaces to the axon. Myelin movements other than those occurring at the Schmidt-Lanterman clefts consisted primarily of the development and frequent regression of indentations of the myelin sheath. A single evagination was seen to develop and then to recede. These myelin movements suggest that previously described invaginations and evaginations of the myelin sheath, including flaps of “redundant myelin”, are not static but rather that they are in a state of movement, forming and regressing at intervals. The possible functional significance of the development and regression of myelin sheath indentations in relationship to axoplasmic flow is discussed.

Impulses in single muscle spindle afferents from the antebrachial finger flexor muscles were recorded from the median nerve of waking human subjects. The discharge frequency in the steady state was measured as the metacarpo-phalangeal joint angles were passively changed in steps. At a comfortable resting position of the hand, less than ten percent of the spindle primaries were discharging. Within intermediate ranges of muscle lengths the discharge frequency of the single units did not exceed 20 impulse per second (ips). The response to joint movements was that expected from muscle stretch and muscle release alone and there was no indication of fusimotor adjustments as a result of joint movement. The frequency of the single units increased linearly with joint extension, the mean sensitivity of the primaries being 0.18 ips per degree which is about 5 times lower than the sensitivity of de-efferented spindles in cat ankle extensors. The afferent discharge from the secondaries was in most respects very similar to that of the primaries. The low discharge frequency, the low percentage of active units and the low position sensitivity all indicate an insignificant fusimotor outflow to relaxed human hand muscles and a comparatively poor ability of the spindles to measure muscle length under these conditions.

The effect of denervation on the morphology and innervation of human muscle spindles has been studied in mixed sensorimotor neuropathies and in sensory and motor denervation in 25 cases examined at necropsy. In sensorimotor denervation the changes found consisted of degeneration and atrophy of the intrafusal muscle fibres, which were often clumped together in the centre of the dilated spindle capsules, degeneration of the equatorial aggregations of sarcolemmal nuclei and, in longstanding denervation, of collagenous thickening of the spindle capsule and deposition of collagen around the intrafusal muscle fibres. There was a reduction in number of sensory and motor nerve fibres in the affected spindles and changes were found in both the sensory and the motor nerve endings. In sensory denervation there was atrophy of the equatorial regions of the intrafusal muscle fibres, with degeneration and loss of the equatorial nuclei and simplification and degeneration of the primary and secondary sensory endings. Excess intraluminal collagen was sometimes found in the equatorial regions. The polar parts of the spindle capsules and of the intrafusal muscle fibres, and the fusimotor innervation, were normal. In tabes dorsalis attempts at regeneration of the sensory endings were sometimes recognisable and there was swelling and attenuation of the terminal part of the primary and secondary sensory axons. In motor denervation degenerative changes were found in both gamma and alpha-collateral fusimotor nerve fibres and motor endings, and in some spindles no motor nerve fibres could be identified. The polar regions of the intrafusal muscle fibres were thin and atrophic, and, as in sensorimotor denervation, degeneration of nuclear chain fibres was more prominent than, and preceded, degeneration of nuclear bag fibres. This could not easily be related to the differing patterns of innervation of these two types of muscle fibre, but seemed to be due to structural differences in the fibres themselves. The equatorial regions of these intrafusal fibres and their sensory innervation were normal.

Measurements of motor nerve conduction velocity are reported in 88 subjects from 20 families in which a clinical diagnosis of peroneal muscular atrophy had been made in the index cases. The values display a bimodal distribution. The majority of cases show a substantially reduced conduction velocity, a smaller group displaying velocities within the normal range or only slightly decreased. This difference was demonstrated to have a genetic basis.

In a patient with reflex myoclonus limited to the right side of the body, stimulation of the right median nerve in the index finger or wrist elicited a very large somatosensory evoked response (SER) and a long loop C reflex which represents an electrically evoked myoclonic response. It is suggested that the pathway for the C reflex is through peripheral nerve, dorsal funiculus of spinal cord, contralateral VP nucleus of thalamus, sensorimotor cortex, corticospinal tract, and anterior horn cell. The large SER, C reflex, and myoclonic jerks are presumed to result from a release effect causing increased excitability at central synapses along this pathway. The patient presented has a large atrophic vascular lesion involving the left frontotemporoparietal region and involvement of pathways through the right superior cerebellar peduncle to account for the neural dysfunction.

Relative and absolute refractory periods were determined in sensory fibres of 24 median nerves and in 19 sural nerves of 30 volunteers aged 20–60 years, who had no sign of a neuromuscular disorder. Th

The contribution of the fusimotor system to reflex reinforcement such as the Jendrassik manoeuvre was investigated by recording single unit activity with tungsten electrodes from muscle spindle afferent nerves in unanaesthetized normal human subjects. Muscle spindle afferent activity was recorded before, during, and after the reinforcement test. When the leg muscles remained relaxed during the Jendrassik manoeuvre, spindle activity recorded in the tibial nerve was accelerated. Also in the median nerve, activity from muscle spindle afferent fibres was increased during a remote contraction of the ipsilateral quadriceps muscle. Comparing the time course of the phasic reflex reinforcement and the muscle spindle facilitation during the remote contraction, a marked after-effect was recorded in both responses. Present results show an increased spontaneous muscle spindle activity in relaxed muscles during a remote muscle contraction, and provide evidence for the contribution of the fusimotor system to the enhancement of phasic reflexes by reinforcement manoeuvres.

✓ Two patients with cough syncope and herniated cerebellar tonsils apparently of congenital origin are reported. Neither had hydrocephalus or any evidence of neoplasm. Tests were done in one patient during coughing: the resting cerebrospinal fluid pressure fell; the transmitted pulse pressure waves disappeared; hypotension, bradycardia, and occipital headache developed; and evoked potential amplitude was markedly reduced. All findings returned to control values within 2 minutes. After suboccipital craniectomy and upper cervical laminectomy, neither patient has had recurrence of cough headache or of cough syncope. A mechanism for this event is suggested.

Motor conduction velocity along the forearm segments of the ulnar and median nerves was studied in 25 patients with Charcot-Marie-Tooth disease. It was found that there was a spectrum of values between 68 and 10 m/sec for the ulnar and between 60 and 15 m/sec for the median nerve. Although a neuronal disorder is expected in patients with normal or slightly diminished conduction velocity values and a Schwann cell disorder is expected in those with marked slowing of conduction, alternative hypotheses are offered to reconcile those differences with the notion that these patients belong to an homogenous group.

A high incidence of asymptomatic neuromuscular disease was found. More than half showed EMG evidence of a `myopathy' and of denervation. The commonest syndrome was a neuromyopathy with myopathic units and spontaneous muscle activity, especially fasciculations and nerve fibre loss but with normal or near normal nerve conduction. This is thought to be the result of a neuronal or axonal disorder.

C unit responses to intradermal electrical stimulation were recorded with tungsten micro-electrodes inserted percutaneously into intact human cutaneous nerves. An increase in discharge frequency was associated with a decrease in conduction velocity in unmyelinated fibres, and this phenomenon was used to identify afferent C units which responded to both electrical and natural stimuli in the skin. Antidromic impulses in efferent, sympathetic fibres were also elicited by electrical stimulation in the skin as judged by latency changes or signs of collisions in the C responses associated with activity in sympathetic fibres. In this way, conduction velocities in distal segments of both afferent and sympathetic C fibres can be estimated. Furthermore, the possibility to differentiate afferent and sympathetic C units is of obvious importance for the study of their respective discharge characteristics and in psychophysiological studies in alert man.

Nine patients are described with unilateral wasting of the hand muscles associated with elongated C7 transverse processes or with rudimentary cervical ribs. In three patients there was selective wasting of the lateral part of the thenar pad, accompanied by mild weakness of the other hand muscles. In four patients all the hand muscles were wasted, but this was more marked in the lateral part of the thenar pad than elsewhere. In two patients wasting was uniformly distributed throughout the hand. Weakness and wasting in the forearm was only present in four patients and was relatively mild. Sensory loss, when present, affected mainly the inner side of the forearm. Nerve conduction studies revealed no abnormality in the distal part of the median nerve, but some patients had reduced or absent sensory action potentials when the fifth finger was stimulated. In all nine patients a sharp fibrous band was found at operation, which extended from an elongated C7 transverse process or from a rudimentary cervical rib to the region of the scalene tubercle on the first rib. The fibrous band caused angulation of the C8 and T1 roots in five patients, and of the lower trunk of the brachial plexus in three. Pathological changes were frequently visible in affected nerves at the site of angulation. Division of the fibrous band relieved pain and paraesthesiae in eight patients and arrested muscle wasting and weakness in nine patients. There was, however, only slight recovery of power in affected muscles; wasting in the hand appeared to be unchanged after periods of up to eight years.