Visual evoked potentials in diabetic patients.

Visual evoked potentials (VEPs) were assessed in 50 adult type I (insulin-dependent) and 19 type II (noninsulin-dependent) diabetes mellitus patients and in 54 controls. P100 wave latency was significantly longer in diabetic patients (P less than .001). Twenty-eight percent of diabetic patients had P100 wave latencies above the normal range. There was no correlation between P100 latency and type or duration of diabetes mellitus, quality of metabolic control, or presence of degenerative complications. The significance of VEP abnormalities in diabetes mellitus remains speculative.

[HLA and familial multiple sclerosis]. / HLA et scléroses en plaques familiales.

Some data suggest an environmental perhaps a viral factor but also of a genetic factor in the etiology of multiple sclerosis. Among the latter is the notably increased risk for a twin when the other twin has the disease, a risk further increased if they are monozygotic. There is also a greater than chance frequency of common HLA haplotypes in 2 affected siblings. The frequency of familial forms of multiple sclerosis is estimated at approximately 6 p. 100. We have studied 14 families of which 12 included 2 members with multiple sclerosis and 2 with 3 affected members. Parental relation between patients was parent to child (7 cases), brother to sister (5 cases), sister to sister including two pairs of twins (4 cases) and cousin to cousin on the mother's side (2 cases). When compared with non-familial multiple sclerosis there were no particular features in clinical disorders or course: 4 forms were progressive, the others evolving by episodes. In 26 patients in whom HLA antigens were determined, the DR2 antigen was present 19 times, the B7 antigen 9 times and the A3 antigen 7 times. In the 8 pairs of siblings with multiple sclerosis, 2 were HLA-identical and 5 semi-identical. One pair had no common haplotype. Grouping of HLA in 22 healthy members allowed 8 genealogic trees to be established. If a gene for susceptibility to multiple sclerosis exists, it is of low penetration, of dominant transmission and of limited frequency. It probably lies close to the region D of chromosome 6, because of the disequilibrium of crossed linking with A3, B7 and DR2 antigens.

[Familial presenile dementia: Gerstmann-Sträussler-Scheinker's syndrome (author's transl)]. / Démence pré-sénile familiale: syndrome de Gerstmann-Sträussler-Scheinker.

A similar affection has developed in eight members from four generations of a family living in the Alsace. The disease is characterized by the onset of a pyramidal, pseudobulbar syndrome and dementia during the third or fourth decade of life. The outcome is fatal after a mean period of three years. Cerebral biopsies in three cases have demonstrated multicentric amyloid plaques differing from senile plaques. Clinical and pathological findings are similar to those currently reported in the literature as being typical of Gerstmann-Sträussler-Scheinker's syndrome. The affection appears as a separate entity: the multicentric plaques, clinical symptomatology, pyramidal or pseudobulbar, cerebellar syndromes, usually preceding dementia, age of onset, course, and familial character or the disorder distinguish it among presenile dementias. Its clinical profile and course are very similar to that of familial cases of Alzheimer's disease, some of which are probably cases of Gerstmann-Strässler-Scheinker's syndrome. Transmission to animals, though inconstant, places it within the group of transmissible dementias among kuru, Creutzfeldt-Jakob's, and familial forms of Alzheimer's disease. The familial nature of the affection and the variability of clinical and pathological features in the same family illustrate the complex relationships between hosts and pathogenic agents in the clinicopathological expression of a disease.

[Significance of abnormally high somatosensory evoked potentials (SEV)]. / Signification des potentiels évoqués somesthésiques (PES) d'amplitude anormalement élevée.

Data found in the literature and our own observations prompted us to consider the possibility that abnormally enlarged Somatosensory Evoked Potentials (SEPs) may have a diagnostic and physiopathological significance, particularly in a group of diseases which include common clinical features of encephalopathy with stimuli-sensitive myoclonus and epilepsy, whatever their etiology may be (degenerative or storage disease, metabolic, toxic or post-hypoxic encephalopathy...). We discuss the amplitude, morphology, diagnostic and therapeutic contribution of these 'giant' SEPs and pathogenic assumptions with reference to 'cortical reflex myoclonus'. Studies of back-averaged encephalogram, SEPs and long-loop reflexes allow some illustration of a functional hyperreactivity of the sensori-motor cortex, but no conclusive demonstration of its origin.

[Changes in somatosensory evoked potentials during EEG activation by bemegride in man]. / Modifications des potentiels évoqués somesthésiques au cours de l'activation EEG par bémégride chez l'homme.

The use of evoked potentials for the evaluation of neuronal mechanisms by which convulsant drugs activate epilepsy and produce seizure has been reported by many authors. Electrophysiological effects of bemegride with augmented responsivity of brain structure to sensory stimulation is well known, especially in experiments performed with implanted electrodes in animals. After recording evoked activity from parietal scalp following median nerve stimulation before and during 12 human EEG activations by bemegride, the authors find an increase in amplitude of cortical somatosensory evoked potentials. Changes in amplitude after diazepam administration are analysed, as well as morphological changes preceding and following grand mal seizures induced by bemegride administration. This variation in amplitude of evoked responses is compared with those recorded in animals with several convulsant drugs and in man affected with progressive myoclonic encephalopathies. A common action of these agents, beyond their effects on specific neurotransmitters (perhaps mediated by a blockade of neurotransmitter-induced chloride conductance increases), is discussed.

[Spinal cord compression caused by spinal aneurysmal bone cyst (author's transl)]. / Compression médullaire par kyste anévrismal vertébral

Spinal aneurysmal bone cyst is sufficiently rare for the authors to report this case with rapid evolution and development of paraplegia. Total removal was achieved, and clinical recovery remained complete six months after operation. The pathogenic, clinical, radiological, histological and therapeutic aspects are briefly reviewed and discussed.

[Electrophysiologic study of Achilles areflexia of aged subjects]. / Etude électrophysiologique de l'aréflexie achilléenne du sujet âgé.

The elderly often presents loss of Achilles tendon reflex. In this electrophysiological study the authors examined 19 patients with loss of the ankle jerk and with no known etiology of peripheral neuropathy. They compared them with 24 subjects who had no areflexia. The study included measurement of the H reflex, of the tendon reflex, of the conduction velocity of Ia fibers and of motor conduction velocity of the tibial nerve. Amplitude of H and tendon response and H/M ratio are diminished in the areflexic group. In 4 cases the H reflex is preserved while the tendon reflex is abolished. The meaning of these impairments is discussed.