Alteration of event related potentials in siblings discordant for schizophrenia.

This study was aimed at confirming that auditory event related potential (ERP) abnormalities are indicators of vulnerability to schizophrenia. Auditory ERP performances were assessed at Fz, Cz, and Pz, with an oddball paradigm, in 21 clinically stable patients with schizophrenia, 21 of their healthy biological full siblings and 21 control subjects. The evoked response did not differ between the three groups on N200 waves. Compared to controls, patients with schizophrenia exhibited reduced amplitudes of N100 and P300, and prolonged latency of P300, while their siblings showed prolonged latency of P200 and P300. Among the patients with schizophrenia, ERP abnormalities did not correlate with age, clinical state, duration of illness or antipsychotic treatments. Although other conditions also accounted for alterations of the same type, ERP abnormalities may represent a neurobiological marker of the genetic vulnerability to schizophrenia, independent of phenotypic expression.

Increased serum levels of neuron-specific enolase in epileptic patients and after electroconvulsive therapy--a preliminary report.

Serum neuron-specific enolase (NSE) levels were studied by an enzymo-immunoassay method in 2 groups of patients: a group of epileptic patients, and a group of patients with refractory major depression after electroconvulsive therapy (ECT). In patients without organic neurological disease (n = 274) the mean serum NSE level (+/- S.D.) was 8.4 +/- 3.4 micrograms/l. No correlation with sex or age was observed. No significant difference was observed between epileptic patients without seizure or major electroencephalogram (EEG) abnormality, and a reference group. Significant increases were observed in 32 samples collected from patients with interictal EEG without spikes and waves before the 7th day after a seizure, in whom mean NSE was 21.5 +/- 9.4 micrograms/l, and in 26 samples from 4 patients without seizures but with spikes and waves in the interictal EEG, whose mean NSE was 20.6 +/- 11.5 micrograms/l. The increases of serum NSE levels in epileptic patients seem therefore to be linked to seizures and/or to EEG abnormalities. The consequences of these observations for the survey of epileptic patients, and for the diagnosis of cerebral tumors (mainly neuroblastoma) or for monitoring treatment after surgical resection, are discussed. In only 1 patient out of 6, an increase in serum NSE levels was observed with a peak about 12 h after ECT. No significant correlation with the ECT features (length of seizures, one- or two-sided electrodes) was observed.

[Electrophysiologic data on myasthenic syndromes of the Lambert-Eaton type. A series of 23 cases]. / Données électrophysiologiques dans les syndromes myasthéniformes de type Lambert-Eaton. A propos d'une série de 23 cas.

The electrophysiological data of 23 adult patients with Lambert-Eaton myasthenic syndrome (LEMS) have been reviewed. Lung carcinoma was disclosed in 17. In six cases with an EMG follow-up ranging between one and 17 years no carcinoma was detected. The results of repetitive nerve stimulation test (RNS) were not statistically different between the 2 groups. Low CMAP ulnar amplitude was present in all patients (mean: 1.7 mV). Decremental response at low rate of stimulation (3 Hz) was present in 17/20 (means: 30%). An abnormal incremental response at high rate of stimulation was present in all cases (mean: 826%). The authors emphasize the interest of a 50 Hz stimulation for 4 s. Increase of the 'F-wave' amplitude was noticed in some cases. Electrophysiological changes suggestive of an associated mild neuropathy were noticed in eight patients but H-reflex was present in 3/3 cases. SFEMG abnormalities were found in 6/6 cases. In one case, stimulated SFEMG showed more blockings and an increased jitter with low rate of stimulation. In one case the electrical pattern of RNS could be misinterpreted as myasthenia gravis in one tested muscle only. The author's results suggest that CMAP amplitude and RNS test could be used to appreciate the short-term improvement of LEMS with treatment and in some cases for the long-term follow-up.

[Ballerina steps, symptom disclosing hypertrophic Charcot-Marie disease with dominant transmission. Value of electrophysiological studies]. / La marche en ballerine, symptôme révélateur d'une maladie de Charcot-Marie à forme hypertrophique avec transmission dominante. Intérêt des explorations électrophysiologiques.

Three children referred for electromyographic investigations presented difficulty in standing upright and in walking. They walked on the points of the feet. The disorder had appeared several years after the development of normal walking. Electrophysiological tests demonstrated a severe peripheral neuropathy with slowing of motor conduction in all four limbs and severe disturbances of sensory conduction. The purely peripheral nature of the lesion was confirmed by studying cortical somatesthetic potentials. E.M.G. and stimulus-detection examinations in family ascendants free from any clinical disorders revealed a similar neuropathy. Biopsy confirmed the presence of a demyelinating neuropathy with schwannian hyperplasia in adult subjects. Biological tests showed anomalies of blood saturated/unsaturated fatty acid ratios. This represents therefore a rather unusual initial clinical presentation of a hypertrophic form of Charcot-Marie's disease with dominant transmission, or form I in Dyck's classification of sensory-motor hereditary neuropathies. Families of children presenting this type of clinical or electrical picture should undergo routine electrophysiological tests. In this way, a whole series of peripheral neuropathies previously considered as sporadic or transmitted in a recessive mode will be found to form part of the group of dominant forms.

[Neuropathy following treatment of chronic active hepatitis with vidarabine]. / Neuropathie après traitement d'une hépatite chronique active par vidarabine.

In a patient with chronic active hepatitis (CAH) due to B-virus, a polyneuropathy developed following a cure of vidarabine. The pathophysiology of this neuropathy remains unclear as it appears not to occur in patients with diseases other than CAH. Muscular pains and paresthesias reported in such patients treated with vidarabine could be the consequence of peripheral nerve involvement.

[Early somatosensory evoked potentials: a means of investigation of the lemniscal pathways (author's transl)]. / Intérêt des potentiels évoqués somesthésiques précoces dans l'exploration des voies de la sensibilité lemniscale.

The recording of the somatosensory evoked potentials (SEP's) elicited by stimulation of the median nerve is a non painful and non invasive mean to investigate the function of the different levels of the lemniscal pathways: peripheral nerves, dorsal root ganglia, dorsal funiculi, brainstem, thalamus, and somesthetic cortex. Recording technique, normative data in adults and abnormalities due to neurological diseases are reviewed. This investigation appears to be of peculiar interest in lesions of dorsal roots, cervical spinal cord and brainstem. SEP's recording may also be helpful for the functional testing of the somesthetic pathways in patients with disorders of consciousness.

[Vulnerability to schizophrenia. II: Familial status of auditory evoked potential abnormalities]. / Vulnérabilité à la schizophrénie. II: Nature familiale des anomalies des potentiels évoqués endogènes auditifs.

The existence of a genetic background is well admitted in schizophrenia, but some individuals at genetic risk for that disease could never manifest it at a clinical level. However, several vulnerability models could help us to identify such individuals. According to them, when similar perturbations at a given task are observed both in clinically stable patients with schizophrenia and their nonschizophrenic first degree relatives, this task could be qualify as an indicator of the vulnerability to schizophrenia. In literature, that seems the case for auditory ERP late components in oddball paradigms. Our study was undertaken to replicate literature data. For that purpose, amplitude and latencies of auditory N100, P200, N200 and P300 wave-forms were assessed among 21 clinically, stable schizophrenics, 21 of their biological full siblings and 21 unrelated control subjects matched with the two others groups for several socio-demographic factors. Comparison were performed by non parametric analyses (Kruskal-Wallis one way ANOVA, and post-hoc Mann-Whitney). Compared to controls, delayed latencies and/or reduced amplitudes were observed for several ERP components--mainly with P300--in the sibling group. ERP values from this group did not statistically differ from those of the group with schizophrenia. In conclusion, results from the sibling group suggest that ERP impairments in auditory oddball paradigms may actually represent indicators of the genetic vulnerability to schizophrenia.

[Normal sensory nerve conduction velocities of the median and ulnar nerves in children from birth to 15 years]. / Vitesses de conduction sensitive normales des nerfs médian et cubital chez l'enfant de la naissance à quinze ans.

Conduction velocity of the fastest fibres in sensory nerves (SCV), amplitude and shape of the sensory evoked potentials (SEPs) were studied in 94 normal children aged 5 days up to 15 years. Surface electrodes were used both for nerve stimulation and sensory evoked potential recording. Normal minimal value in young adults is reached between 2 and 4 years of age, earlier in the proximal segment of the nerve (wrist-elbow) than in the distal segment (digit-wrist). Amplitude of the median SEP at the wrist increases about 155% during the first 2 years of life; this increase becomes more progressive and moderate from 2 to 15 years of age. At the elbow, the SEP has a smaller amplitude and is made of two separate peaks in 80-100% of the children between 6 months and 10 years of age. The presence of those two separate components lends substance to the view that there are two groups of fibres with different degrees of maturation. Methodology and results are discussed along with previous data from the literature.

[Cerebral arterial embolism during extracorporeal circulation]. / Les embolies artérielles cérébrales en cours de circulation extra-corporelle

From October 1st 1970 to October 1st 1975, electrical and clinical post-operative observation of 1.700 operations under E.C.C. allowed record of E.E.G. and thus study incidents depending of cerebral embolism during their formation. 18 cases have been seen during E.C.C. and 2 at the stop of E.C.C. In 9 cases, it was an air embolus, in 4 others an atheromatous embolus. In the 7 remaining cases, origin of the embolus is uncertain, but probably gaseous. Semiology of the accident is first only E.E.G. In 10 cases, signs were minor, and moderate in 10 others, preceding a late but hard clinical symptomatology, frequently characterized by a delayed advent of epilepsy crisis. Later on, an annoying evolution of the accident was seen in 4 cases (1 death, 3 lasting neurologic deficiency). For the treatment, many observations confirm the highly beneficient part of early hyperbaric oxygen.

[Transitory EEG asymmetry at the start of quiet sleep in the newborn infant: 75 cases]. / Asymétrie EEG transitoire à l'entrée dans le sommeil calme chez le nouveau-né: étude sur 75 observations.

75 transient EEG asymmetries occurring during quiet sleep were studied. These asymmetries were obtained from 73 polygraphic recordings registered in 73 neonates. These infants represented 3.17% of all the neonates registered during the neonatal period in a department of neonatology (2297 neonates registered between July 1974 and July 1982). The pattern of these asymmetries was always identical, it consisted of a sudden flattening of the EEG activity occurring on one hemisphere followed on this hemisphere by an EEG activity which was more discontinuous and less mature than on the other hemisphere. These asymmetries were transient, lasting from 1 to 5 min. They occurred at the beginning of quiet sleep. The EEG activity before and after the asymmetry was almost always normal. The analysis of the clinical data showed that the infants who presented an EEG asymmetry during quiet sleep had a conceptional age ranging from 35 to 44 weeks, and that they were hospitalized for a minor illness which turned out to be a neurological disorder in only 2 cases. It showed that all the infants who were followed later, except one, developed normally. The physiological mechanism of these asymmetries is discussed and it is concluded that they are functional, probably enhanced by a sleep deprivation and not associated with a focal pathology.

[Value of electromyography in the child. Apropos of 1,624 examinations performed over a 3 year period]. / Intérêt de l'électromyographie chez l'enfant. A propos de 1624 examens réalisés en 3 ans.

EMG and nerve conduction studies have limitations and require particular consideration in children. The indications and the main results are considered from the study of 1624 EMGs in 1385 children under 15 years old seen over a period of 3 years. Classification of cases was based on clinical criteria. The diagnostic yield of EMG is emphasized in the evaluation of 122 children with hypotonia and weakness (all under 3 years old); abnormalities were demonstrated in 48% leading to the diagnosis of spinal muscular atrophy in 16%, of congenital myopathies in 11%, and of peripheral neuropathies in 8%. In 103 children with hypotonia associated with mental deficiency and/or seizures, evidence of a peripheral neuropathy was shown in 20%. EMG abnormalities allowing the diagnosis of hereditary motor and sensory neuropathies or myopathies were demonstrated in a wide range of clinical conditions. EMG appears to be useful for the early detection of hereditary myopathies or neuropathies in asymptomatic children. It may have also a prognostic value as in adults, especially in nerve traumas.

The role of intraoperative transcranial Doppler monitoring in carotid artery surgery.

Of 135 carotid artery reconstructions performed under general anesthesia in 127 patients (mean age 68 years), 119 were performed with continuous intraoperative Doppler recording of the middle cerebral artery. This investigation was impossible in nine (6.7%) cases because of the absence of a visible temporal window, and results were deemed uninterpretable in six (4.5%) additional cases. The goals of this study were to test the feasibility and reliability of transcranial Doppler monitoring in the evaluation of intracranial perfusion and to determine the risk of cerebral ischemia during carotid artery clamping. The two outcome parameters measured were mean velocity and percentage of decreased flow in the middle cerebral artery during clamping. Patients were divided into four groups based on variations in these parameters. Groups I and IIA (low risk) represented 69.7% of cases, group IIB (significant risk) represented 21.9%, and group III (major risk) represented 8.4%. Transcranial Doppler monitoring appears to be a reliable means of observing middle cerebral artery flow during carotid surgery and in our opinion provides objective criteria for determining the need for an indwelling shunt. Accordingly, in this study no neurologic complications imputable to clamping were observed. Transcranial Doppler monitoring can also be used to ensure correct functioning of the shunt and to detect intraoperative embolic complications.