Showing papers by "David Burke published in 1975"

Fibre function and perception during cutaneous nerve block.

Abstract: In awake human subjects, neural responses in cutaneous nerves to electrical stimulation were recorded with intrafascicular tungsten micro-electrodes. Changes in the activity of individual fibre groups during blocking procedures were recorded and correlated with simultaneous alterations in the perception of standardized stimuli. Light touch sensibility in hairy skin was mediated by A-beta-gamma fibres, cold and pinprick by A-delta fibres and warmth and dull pain by C fibres.

Fibre function and perception during cutaneous nerve block.

Abstract: In awake human subjects, neural responses in radial nerves to electrical stimulation were recorded with intrafascicular tungsten microelectrodes. Changes in the activity of individual fibre groups during blocking procedures were recorded and correlated with simultaneous alterations in the perception of standardized stimuli. Light touch sensibility in hairy skin appeared to depend on the integrity of A-beta-gamma fibres, cold and pinprick on A-delta fibres, and warmth and dull pain on C fibres.

Effects of the Jendrassik manoeuvre on muscle spindle activity in man.

Abstract: Twenty-eight mechanoreceptive units identified as primary or secondary spindle afferents were sampled from muscle nerve fascicles in the median, peroneal, and tibial nerves of healthy adult subjects. The responses of these units to sustained passive muscle stretch, to passive stretching movements, to tendon taps, and electrically-induced muscle twitches were studied while the subject performed repeated Jendrassik manoeuvres involving strong voluntary contractions in distant muscle groups. The manoeuvres had no effect upon the afferent spindle discharges as long as there were no EMG signs of unintentional contractions occurring in the receptor-bearing muscle and no mechanotransducer signs of unintentional positional changes altering the load on that muscle. Unintentional contractions in the receptor-bearing muscle frequently occurred during the manoeuvres, however, and then coactivation of the spindle afferents was observed. Multiunit afferent responses to Achilles tendon taps, led off from tibial nerve fascicles, were in a similar way uninfluenced by the Jendrassik manoeuvres, even when these resulted in marked reinforcement of the calf muscle tendon jerk. The results provide no evidence for fusimotor sensitization of spindles in muscles remaining relaxed during the Jendrassik manoeuvre, and reflex reinforcement occurring without concomitant signs of active tension rise in the muscles tested is presumed to depend upon altered processing of the afferent volleys within the cord.

Cutaneous afferent activity in median and radial nerve fascicles: a microelectrode study.

Abstract: Cutaneous afferent activity was recorded in fascicles of the median and radial nerves of normal subjects using percutaneous microelectrodes. Multi-unit fascicular responses were dominated by activity in large myelinated fibres. Easily tolerated electrical stimuli evoked the full spectrum of fast and slow myelinated fibre activity but more intense levels were required to activate unmyelinated fibres. Correlation of the evoked potentials and the sensations reported by the subject suggested that fast myelinated fibres mediate tactile sensations. Pricking pain appeared with the activation of slow myelinated fibres. The only sensations induced by electrical stimuli were tactile or painful.

An approach to the treatment of spasticity.

Abstract: The term 'spasticity' refers to a specific disorder of muscle tone which may accompany upper motoneurone lesions the resistance to stretch (or the 'tone') being critically dependent on the rate of muscle stretch. Spastic muscles are quiescent at rest, whether in a shortened or stretched position , and slow stretching may fail to evoke a reflex contraction. Management of the patient with spasticity implies more than just treatment of the spasticity. Mere reduction in muscle tone may not be in the patient's best interests, particularly if the abolition of spastic stiffness unmasks severe weakness. The increased tone of spasticity is not harmful to many patients and may be beneficial to some. Active measures to reduce spasticity are only justified where the reflex hyper-excitability positively interferes with function, retards the rehabilitation programme, or makes nursing care difficult.

A phenothiazine derivative in the treatment of spasticity.

Abstract: The efficacy of a selective fusimotor suppressant, the phenothiazine (+/-)-10-3-dimethylamino-2-methylpropyl)-2-valeroylphenothiazine, has been assessed in a double-blind crossover trail in eight patients suffering from cerebral spasticity and one patient suffering from spinal spasticity. Dosage was 40 mg daily. Independent clinical and electromyographic methods of assessment were used. The active agent produced a small but significant reduction in spasticity, although this was of clinical value in only a few patients. There were few side-effects. It is recommended that further studies using higher dosages be undertaken.