Short-latency sinusoidal wavelets to bright flashed stimuli: studies with corneal lens, nasopharyngeal, retrobulbar and scalp recordings.

Short-latency flash visual evoked potentials (VEPs) and electroretinograms (ERGs) were recorded in 30 healthy volunteers and 14 patients (7 with retrobulbar neuritis and 7 with retinitis pigmentosa). Simultaneous recordings were performed by corneal, scalp, nasopharyngeal and retrobulbar (5 patients) electrodes. In 18 out of 30 healthy controls a brief sequence of oscillating wavelets was recorded between 15 and 40 ms on the scalp sites behind the vertex. In retrobulbar neuritis (RBN) patients normal responses were recorded by lens, retrobulbar, nasopharyngeal and frontal scalp electrodes. On the contrary none of these patients displayed short-latency activity behind the Cz scalp position. In 5 out of the 7 patients with retinitis pigmentosa, corneal, nasopharyngeal and scalp electrodes failed to detect any reliable waveform time-locked to the flash onset. In the remaining 2, a small lens ERG was recorded, while all other electrodes recorded a sequence of low-volted wavelets initiating 30 ms after the stimulus onset. In these patients an occipital VEP reduced in amplitude and with prolonged latency was also recorded. It is concluded that in presence of a normal corneal ERG because of the presence of volume spread oscillating retinal activity, it is hard to define while part of the scalp recorded, short latency, oscillating potentials is generated in subcortical visual structures.

A longitudinal study of multimodal evoked potentials in diabetes mellitus.

Abnormal findings in visual (VEP), brainstem auditory (BAEP) and somatosensory (SEP) evoked potentials at early stages of Type 1 and Type 2 diabetes have recently been reported by our group. Our aim here was to perform a longitudinal study in diabetic patients at an early stage of the disease using a combined evoked potential analysis in order to evaluate the variation of neurological abnormalities over time. Nine Type 1 and 12 Type 2 diabetic patients were examined and a second recording was carried out after a mean interval of 15.7 months +/- 6.2 SD. VEP, BAEP and SEP were measured in all patients. At the first recording electrophysiological abnormalities, present in both Type 1 and Type 2 diabetes were more evident when a multimodal evaluation was used (44.4% and 66.7% respectively). The follow-up study showed that overall neurological abnormalities persisted in all those patients who had previously presented pathological values. Whereas the number of patients with pathological values remained unmodified, a tendency to progression, namely the number of nervous levels with electrophysiological abnormalities, was observed. Thus, our study confirms the appearance of anatomofunctional disorders in the central nervous system in short-term diabetes, shows the persistence of neurological impairment in such patients and reveals a progressive segmental involvement at different nervous levels.

Multimodal evoked potentials in neuro-Behçet: a longitudinal study of two cases.

Two neuro-Behçet patients have been studied, over a period of several months, by means of peroneal and median somatosensory- (SEP), brainstem auditory- (BAEP), and visual- (VEP) evoked potentials. In both patients, peroneal SEP showed evidence of a pathological reduction in the central conduction velocity without a related deep sensation impairment, while VEP changes were consistent with the visual disorders. Conversely, BAEP and median SEP findings did not show disease-related abnormalities. The observed anomalies were detectable irrespective of the clinical phase of the disease. Thus, evoked potential assessment is useful in providing objective evidence for evaluating and monitoring CNS damage in neuro-Behçet's syndrome.

Brainstem auditory evoked potentials in toxic, metabolic and anoxic coma.

The aim of this study was to evaluate the efficacy of brainstem auditory evoked responses as a prognostic tool in conditions of coma which interfere with cerebral metabolism. Thirteen patients in coma resulting from different systemic disorders (barbiturate intoxication, cardiac arrest, chronic hepatic insufficiency) were included in the study. Brainstem auditory evoked potentials were recorded and patients were graded according to the results. When used in conjunction with other clinical parameters (Glasgow Coma Scale), brainstem auditory evoked potentials provided a more reliable prognostic tool than the traditional EEG exam alone. A good correlation was found between electrophysiological data and clinical outcome not only in barbiturate (toxic) coma, but also in hepatic (metabolic) coma. Of particular significance was the disappearance of the components which follow wave III (grade 2), leading to a fatal outcome in all three patients in hepatic coma.

Endogenous evoked potentials and vigilance levels variations.

The authors consider the possible relationship between the autonomic functions and the contingent Negative Variation (CNV). This relationship has been found both in psychopathological conditions and after the administration of psychotropic drugs. Some preliminary data are reported on the correlations observed between CNV and the autonomic activation (R-R interval) during a sodium lactate infusion.

Multimodal evoked potentials and CSF findings in the diagnosis of multiple sclerosis.

A group of 30 patients classified on clinical grounds as having definite (N = 16) or probable MS (N = 14) according to McAlpine's criteria, has been studied using multimodal recordings of evoked potentials (visual, auditory, and somatosensory) and examination of the cerebrospinal fluid (CSF) for oligoclonal bands and Link's Index. Evoked potentials examination proved extremely sensitive in discovering asymptomatic lesions of the central nervous system. CSF data, in particular the presence of oligoclonal bands, had a high sensitivity for MS. According to these electrophysiologic and immunologic results, we have reclassified our patients in conformity with the diagnostic criteria proposed by Bartel. The combination of electrophysiological and CSF data, together with common clinical criteria, led to greater diagnostic accuracy, making it possible to reclassify most patients previously considered to have probable MS as having definite MS.

Event-related potentials as a tool in the evaluation of cognitive functions in young subjects through the execution of a simple task.

Event-related potentials (ERPs) were recorded in 20 student volunteers. Three recordings were performed using aural stimuli of 4,000 (rare tones) and 250 Hz. In the target recording subjects were asked to count the rare tones. Endogenous and exogenous components of ERP recordings were analyzed. During the target recording N2 and P3 components were observed at 200 ms and approximately 300 ms, respectively, in addition to N1 (100 ms) and P2 (180 ms). The N2 and P3 waves are indicative of analysis at a higher cognitive level and have been termed the 'response set'. The P3 wave appeared to be stable in all subjects and may represent a useful electrophysiological method to explore mnemonic and cognitive functions in man.

Parkinson disease: electrophysiological (CNV) analysis related to pharmacological treatment.

The contingent negative variation (CNV) was studied in a group of patients with Parkinson's disease. Testing was carried out 3 times: after a pharmacological wash-out period and at 15 and 30 days after the start of treatment with L-DOPA and bromocriptine. Peak and area CNV increased significantly after each treatment. The post-imperative negative variation (PINV) was observed in 6 out of 10 patients. The correlation found between electrophysiological functioning (CNV) measures and pharmacological treatment supports the view that dopaminergic brain activity mediates the generation of the slow negative event-related brain potentials.

Antiepileptic effects of a calcium antagonist (nimodipine) on cefazolin-induced epileptogenic foci in rabbits.

The epileptogenic properties of cefazolin (CFZ) were utilized to induce an electrophysiological pattern of epilepsy in the rabbit. CFZ, cortically applied in different concentrations (2 or 4%), produced epileptic activity in a degree proportional to the concentration of the substance. In this experimental epilepsy model, we evaluated the effects of increasing doses (0.025, 0.05, and 0.1 mg/kg i.v.) of the calcium antagonist nimodipine (Bay e 9736). In the evaluation of nimodipine effects, the spike-and-wave burst frequency per minute was taken into account. These data were compared with those of placebo-treated (Bay e 9736 control test) control groups and statistically evaluated by two-tailed t test. In 2% CFZ-induced epilepsy, nimodipine at the 0.025- and 0.05-mg/kg doses did not produce significant changes in the EEG pattern. A statistically significant reduction (p less than 0.001) in epileptic activity was observed at the 0.1-mg/kg nimodipine dose. This reduction was seen first in the contralateral focus leads and persisted for the entire time of observation. In the more intense epileptic form (4% CFZ), nimodipine at the doses employed did not induce noteworthy EEG modifications. These data indicate that nimodipine exerts an antiepileptic effect. The possible mechanisms involved in this activity of a calcium antagonist are discussed.

[3 cases of essential blepharospasm: pathogenetic problems correlated]. / Tre casi di blefarospasmo essenziale: problemi patogenetici correlati.

Three clinical cases of essential blepharospasm are discussed. On the basis of both therapeutical results and a review of the literature, pathogenetic hypothesis concerning such pathology are reexamined.

[Longitudinal study of evoked responses (VEP, BAEP, SSEP) in multiple sclerosis]. / Studio longitudinale delle risposte evocate (PEV, BAEP, PES) nella sclerosi multipla.

The Authors have examined 20 subjects affected by "possible" multiple sclerosis by means of a multimodal (VEP, BAEP, SEP) electrophysiologically evaluation longitudinally conducted during a time period of 1 year. The electrophysiological data obtained are related to the clinical picture, the disease's evolution, and to the adopted pharmacological therapy, in order to attempt a more precise diagnostic and prognostic assessment of these patients.

[Articulation disorders in aphasia. Considerations in several clinical cases]. / Disturbi dell'articolazione ed afasia. Considerazioni su alcuni casi clinici.

Selective deficit of verbal output not associated to other anomalies of language, represents a syndrome in which articulatory as well as linguistic aspects can be independently affected. The critical lesion for pure articulatory deficit appears to involve left prerolandic cortico-subcortical structures. Nevertheless, in relation to individual differences in cerebral organization, damage in these structures can be responsible for a simultaneous deficit of articulatory and linguistic mechanisms.

[Dopaminergic receptors]. / I recettori dopaminergici.

The functions of multiple brain dopamine receptors are discussed in relation to the physiological role of dopamine in CNS.

[Electrophysiologic profiles in a few cases of Wolfram syndrome]. / Rilievi elettrofisiologici in alcuni casi di sindrome di Wolfram.

The authors have examined some electrophysiologic data in two couples of siblings with Wolfram's syndrome and in the unaffected sister of one of the couples. The results confirment the involvement of some neurologic structures and show up how the Evocated Potentials can disclose a damage in the a.m. structures even lacking clinical features.

[Syringomyelia. Clinical and neurophysiologic correlations (SEP) as a function of surgical treatment]. / La siringomielia. Correlati clinici e neurofisiologici (PES) in funzione del trattamento chirurgico.

The authors have studied the somatosensory evoked potential (SEP) behavior following stimulation of upper and lower limbs in two subjects affected by syringomyelia. The patients were evaluated electrophysiologically before and after decompressive surgical treatment. The findings indicate a positive correlation between the SEP recordings and the role of CSF pressure in the central nervous system.

Pain, anxiety, and contingent negative variation: a clinical and pharmacological study.

Contingent negative variation (CNV) behavior was studied in 16 volunteers who were suffering from spontaneous recurrent pain syndromes (idiopathic trigeminal neuralgia, classic migraine). The subjects were divided into two groups, "more anxious" and "less anxious," based on psychometric tests (MMPI and STAI X2). The CNV recordings were carried out, respectively, in basal resting state, during an episode of pain, while under anxiolytic treatment, and lastly, during an episode of pain while under anxiolytic therapy. CNV voltage decrease and frequent appearance of postimperative negative variation (PINV) were observed when pain was present during the recording session. These phenomena were more marked when the pain was accompanied by a greater degree of anxiety. Finally, our results suggest that this slow evoked potential is sensitive to various degrees of anxiety and to pain perception in man, making it useful in the investigation of pain as a complex sensation.

[Late neuropsychiatric sequelae of carbon monoxide poisoning. Apropos of 3 clinical cases]. / Sequele neuropsichiatriche tardive conseguenti ad intossicazione da ossido di carbonio. A proposito di tre casi clinici.

The authors examined the neuropsychiatric sequelae developed in three patients who had had an acute carbon monoxide poisoning. Computed tomographic (CT) scans were performed as well as psychometric tests. The clinical features and CT scan findings showed to be related to the severity of the initial anoxic insult.

Electrophysiological study in patients with chronic hepatic insufficiency.

Twenty patients affected by chronic hepatic insufficiency were studied by means of combined EEG, VEP and BAEP recordings. Subjects were classified, according to Parsons-Smith criteria, in grade 0 (without any clinical sign) and grade I (with minimal mental disturbances). In group 0 patients an elevated incidence of VEP alterations (40%) was observed, while EEG and BAEP recordings were less frequently (10%) abnormal. In group I patients a high degree of EEG (60%), VEP (70%) and BAEP (70%) abnormalities was found. Mean latency and interpeak interval values in group I patients were significantly prolonged if compared with the grade 0 and control groups. No correlations were found between electrophysiological data and blood biochemical parameters examined (ammoniemia, aminoacidemic pattern).