Showing papers by "Stefan Evers published in 1997"

Cognitive Processing in Primary Headache A Study on Event-related Potentials

Abstract: Background: There is experimental evidence for loss of cognitive habituation in migraine but not in other types of headache and not by visual event-related potentials (ERP). Objective: Determining the latencies (msec) and amplitudes (micro V) of ERP components and the differences of these values in a two-trial analysis representing the amount of cognitive habituation. Participants: Two hundred thirty-three patients with a headache diagnosis according to the criteria of the International Headache Society: migraine without aura (N = 77); migraine with aura (N = 31); cluster headache during period (N = 26); cluster headache during interval (N = 11); chronic paroxysmal hemicrania (N = 8); episodic tension-type headache (N = 33); ergotamine-induced headache (N = 47). Thirty age-matched healthy subjects served as a control group. Methods: ERPs were evoked by a visual oddball paradigm consisting of 2 x 200 flashes of light (85% white light; 15% red light). Evaluation of ERP components was done separately for the first 200 and the second 200 stimuli as well as for the entire series of stimuli. Results: We found an acceleration of the P3 latency during the second trial in migraine with and without aura, but not in the other headache types, and not in healthy controls. Ergotamine and sumatriptan abolished this loss of habituation in migraine patients. Increased ERP latencies as compared with healthy controls were present in patients with cluster headache, tension-type headache, ergotamine-induced headache, and migraine with aura, but not in migraine without aura. Conclusion: There is a loss of cognitive habituation in migraine, which may serve as a specific but not sensitive diagnostic tool. The pathophysiologies of migraine and cluster headache have a specific modifying property on cognitive processing reflected by a loss of cognitive habituation or an increased cognitive processing time. These effects can, in part, be counterbalanced by antimigraine medication. NEUROLOGY 1997;48: 108-113

Features, symptoms, and neurophysiological findings in stroke associated with hyperhomocysteinemia.

Abstract: Background: Hyperhomocysteinemia has been shown to be a mild independent risk factor for premature atherosclerosis, and there is evidence of an increased rate of peripheral vascular occlusive disease, myocardial infarction, and stroke. Objective: To evaluate clinical, biochemical, and neurophysiological findings in patients with ischemic stroke with and without hyperhomocysteinemia. Subjects: One hundred twenty-five consecutive patients with a history of stroke and 60 healthy control subjects. Methods: Patients were divided into those with and those without hyperhomocysteinemia, which was defined as blood levels beyond the mean total plasma homocysteine level plus 2 SDs of the healthy control group. History, symptoms, cause, patterns of infarction, biochemical data, continuous and transcranial Doppler sonography, and event-related potentials were recorded in all patients. Results: Twenty-seven patients had hyperhomocysteinemia. Compared with the 98 patients without hyperhomocysteinemia, they had an increased rate of hypertension (odds ratio, 3.5; 95% confidence interval, 1.0-12.6), an increased level of uric acid ( P P P Conclusions: Hyperhomocysteinemia is probably an independent risk factor for stroke, with a prevalence of about 20% in all patients with a history of stroke; however, additional factors (eg, hypertension, hyperuricemia) may have an enhancing effect. There are significant differences in stroke patterns between patients with and without hyperhomocysteinemia, with a higher rate of lesions typical of cerebral microangiopathy and a trend to multiple infarctions in the former. Impairment of cognitive processing as measured by visual event-related potential is more pronounced in hyperhomocysteinemia.

Cluster headache after orbital exenteration.

Abstract: A 37-year-old man developed an ipsilateral headache which fulfilled the criteria for cluster headache after orbital extenteration because of a traumatic lesion of the bulb. The headache could be treated successfully by drugs usually applied in the therapy of cluster headache. Six similar cases of cluster headache after orbital exenteration could be identified in the literature suggesting that the eye itself is not necessarily part of the pathogenesis of cluster headache. We hypothesize that orbital exenteration can cause cluster headache by lesions of sympathetic structures. Possibly, these mechanisms are similar to those of sympathetic reflex dystrophy (Sudeck-Leriche syndrome) causing pain of the limbs.

Progression of Distal Symmetric Polyneuropathy during Diabetes mellitus: Clinical, Neurophysiological, Haemorheological Changes and Self-Rating Scales of Patients

Abstract: The complex interrelationships between progression of distal symmetric polyneuropathy (DSP) induced by diabetes mellitus and haemorheological alterations in correlation with the patients’ self-rating

Headache caused by a sphenoid mucocele but presenting as an ergotamine-induced headache.

Abstract: In a 65-year-old woman, symptomatic headache caused by a mucocele of the sphenoid sinus led to ergotamine abuse and subsequent ergotamine-induced headache. Since there were no neurological symptoms initially and the patient previously suffered from migraine, the mucocele was not recognized. Only after unsuccessful drug withdrawal therapy and an MRI, was the correct diagnosis made. Surgical removal of the mucocele led to complete relief of headache within 3 weeks. We conclude that ergotamine-induced headache can develop on the basis of symptomatic headache. In spite of the effectiveness of ergotamine tartrate, an MRI should be performed if focal neurological symptoms occur.

Reproducibility of different nerve conduction velocity measurements in healthy test subjects and patients suffering from diabetic polyneuropathy.

Abstract: According to literature, repeated nerve conduction velocity measurement may yield differences of up to 10 m/s in the same subject without any need to regard these differences as pathological. In order to get more details about the reproducibility of different nerve conduction velocity parameters, 59 healthy test subjects and 47 patients suffering from of different nerve conduction investigated. In the sural nerve latency prolongation after paired stimulation, conduction velocity and amplitude of nerve action potential were determined, in the peroneal neuve conduction velocity, distal latency, amplitude of nerve action potential after distal stimulation and F-wave. All investigations velocity, distal using surface electrodes. Measurements were repeated within one day by the same investigator using exactly the same methods. No statistically significant differences between both investigations in test subjects and patients were found. Statistically, results for patients differed significantly from healthy test subjects. Six patients showed discrepancies between both measurements in the individual estimation normal/abnormal in comparison to laboratory norm values. In conclusion, these results demonstrate that strict adherence to technical and methodological parameters -including the same investigator - results in a higher improvement of reproducibility of nerve conduction velocity measurement. Multiple factors are operating in time but strict adherence to technical, methodological, physiological and biological parameters minimises changed results of neurophysiological measurements and improves reproducibility.

Early elevation of cerebrospinal fluid neuron-specific enolase in Creutzfeldt-Jakob disease.

Abstract: predominant, are scattered in the granulomatous infiltrate among giant macrophages and epithelioid cells, whereas CD8 cells are confined to the periphery of the granulomas. It is interesting to note that the infiltrates are devoid of B cells, as in our case. Therefore, the findings from the muscle biopsy in our patient were consistent with the characteristics of sarcoid myopathy and not with those of dermatomyositis, despite the dermatological presentation. Although both of these diseases are marked by a large amount of CD4 cells, the chief sites at which these cells are located are different [3, 8], and the exact role of CD4 cells remains to be established in each disease. Because three of the four previously described patients with associated dermatomyositis and muscle sarcoidosis were Japanese, it is of interest that our patient was Caucasian, which indicates that this association does not constitute a specific genetic particularity.

Side-to-side differences in visual event-related potentials but not VEP in patients with multiple sclerosis: A report of three cases

Abstract: Three patients with definite multiple sclerosis (MS) and acute loss of visual acuity on one side but without side-to-side differences in visual evoked potential (VEP) latencies revealed prolongation of visual event-related potentials (ERP) on the impaired side. These patients represent 5.1 % of a cohort with clinical optic mononeuritis and 21.4% of a cohort with clinical optic mononeuritis but no side-to-side differences in VEP. The data suggest, that in some cases, side different measurement of ERP (rather than VEP) is an appropriate method to prove the sensory or cognitive impairment in patients with MS and clinical optic mononeuritis.