Pain threshold changes by skin vibratory stimulation in healthy subjects.

The purpose of this research is to evaluate the changes of cutaneous pain threshold induced by vibratory stimuli applied to the skin. The pain threshold was tested by means of electrical stimuli using the method of limits. Both vibratory stimuli (conditioning stimuli) and electrical stimuli (test stimuli) were driven by a computer. The experiments were carried out on the dorsal surface of the second phalanx of the index finger in the dominant hand of 34 healthy subjects (18 males and 16 females). The conditioning stimuli were sinusoidal waves (250 microm peak to peak) at a rate of 30 and 300 Hz. During the experiment (6 min of vibration and 9 min after) the cutaneous temperature of the stimulated area was recorded. Both vibratory rates induced significant increases of the pain threshold but the 30 Hz vibrations were the more effective. After stimulation the pain threshold lowered to a steady value which was higher than before the start of vibrations. Such threshold changes showed no correlation throughout the experiment with changes in skin temperature. We therefore advance the hypothesis that the main factors which modulate the pain threshold are neuronal connections between tactile and pain pathways.

Effect of spinal cord stimulation on motor performances in hemiplegics.

Spinal cord stimulation (SCS) was performed in 11 patients with stabilized spastic hemiparesis due to cerebrovascular ischaemic accident in order to improve their motor performances. The patients were studied before and after 5-7 days of stimulation of the cervical cord according to the following protocol: (1) clinical evaluation based on assessment of the neurological status and on Albert's motor scale and (2) neurophysiological evaluation of reflex voluntary and involuntary motor activity, obtained by means of surface electromyography. Improvement in motor performance following SCS occurred in 7 of the 11 patients. The effect appeared to be particularly evident during specific voluntary movements and gait. Analysis of the electromyography recordings showed that SCS mainly broke down pathological patterns of voluntary movement and reduced agonist-antagonist coactivation and clonus. A relationship between motor outcome and status of the sensory function was noticed as well. We conclude that SCS may play a role in the motor rehabilitation of post-stroke patients with spastic hemiparesis, provided that a careful selection be made before surgery.

Cortical and cervical stimulation after hemispheric infarction.

Cortical and cervical stimulation has been performed in 20 patients with hemiparesis or hemiplegia due to hemispheric infarction and in 20 control subjects. The motor action potentials (MAPs) were recorded from biceps and thenar muscles. MAPs evoked by stimulation of the undamaged hemisphere were normal in 18 out of 20 patients and in two there was a slight increase of central conduction time (CCT). The stimulation of the motor cortex of the damaged hemisphere did not evoke any response in 15 patients; in two the MAPs were absent in one muscle and in the remaining three were delayed in one or both muscles. Cervical MAPs were normal in 18 patients and delayed in the thenar muscle in two patients.

[Neuroendocrine aspects of Parkinson's disease. Therapeutic/effect of a prolactin inhibitor]. / Aspetti neuroendocrinologici del morbo di Parkinson. Interesse all'effetto terapeutico di un inibitore della prolattina

On the basis of a reassessment of the aetiopathogenetic problem and the neuroendocrine implications, the therapeutic effectiveness of a prolactin inhibitor, 2-alpha-Br-ergocryptine (CB 154), in Parkinson's disease is assessed. Five patients were treated for a total of two weeks using doses between 10 and 15 mg/die. CB 154 was found to act as a dopaminergic receptor agonist at nigro-striatal level, considerably improving tremor and rigidity and to a lesser extent bradykinesia and total disability.

[Treatment of anxiety in Parkinson's disease with bromazepam]. / Trattemento dell'ansia nel morbo di Parkinson con bromazepam

The Authors observe that anxiety is a rather frequent symptom in parkinsonian patients. The possible mechanisms are reviewed. In a double blind cross-over trial, a new antianxiety agent (Lexotan, Roche) was compared with Placebo, to delineate the therapeutic effect in anxious parkinsonian patients. A noteworthy activity was shown by the active drug, while after Placebo a deterioration of anxiety was demonstrated. Tremor was also alleviated by Lexotan and the importance of emotional troubles on tremor seems to be confirmed.