[Opioid addiction: P300 assessment in treatment by methadone substitution]

The aim of this study was to assess cognitive functions in two clinical conditions, namely during heroin detoxification and during substitution treatment by methadone. Two groups of chronic heroin user inpatients, meeting DSM-III-R criteria for concurrent opiate dependence, were tested using an auditory oddball paradigm of P300. The first group (four women and six men) were drug-free and the second (five women, ten men) received methadone treatment. Patients were also compared to a control group of non-dependent healthy subjects (five women, nine men). The patients were recorded 6-10 days after the beginning of either detoxification or methadone treatment. There were significant P300 alterations in the two patient groups, with amplitude decrease and latency increase, at a time when self-reported signs of withdrawal were absent or minimal. Paradoxically, the reaction time was accelerated in the two groups of patients, who also showed increased discrimination errors. These abnormalities were found with a lesser degree in the methadone-treated group than in detoxification patients.

[Polymorphism of the continuous muscle fibers activity syndrome. Possible relationship with Morvan's fibrillary chorea (author's transl)]

Two cases presenting the main features of the continuous muscle activity syndrome (neuromyotonia) are reported. The clinical particularities between the two patients are under lined. The second case is special because of its acute and reversible evolution and the possible role of gold salts in its etiology. This latter point suggests Morvan's fibrillary chorea. The possible relationships between the two syndrome are discussed.

Effects of postural changes of the upper limb on reflex transmission in the lower limb. Cervicolumbar reflex interactions in man

The influence of passive changes in upper limb position on the excitability of three myotatic arc reflexes (soleus, quadriceps, and biceps femoris) of the lower limb has been explored on 42 volunteers. The results indicate that the excitability of the three myotatic arcs can be influenced at a distance by postural modifications of the upper limb. When the ipsilateral upper limb is forwards or the contralateral backwards, a facilitation of both soleus and quadriceps tendon reflexes is observed while the biceps femoris reflexes are reduced. This pattern of facilitation and inhibition is reversed when the ipsilateral upper limb is backwards or the contralateral forwards. The facilitations as well as inhibitions of proximal myotatic arc reflexes are quantitatively more marked than that of the soleus reflex. Facilitation and inhibition are not linearly related to the angle of the arm with the trunk. Effects begin at a considerable angle, become maximal at 45 degrees, and progressively disappear for greater values. It is suggested that the distinct pattern of facilitation and inhibition which is exerted in reciprocal fashion on extensor and flexor motor nuclei might depend on the long propriospinal neurones connecting cervical and lumbar enlargements.