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Sándor Beniczky

Publications and source records attributed to Sándor Beniczky.

9 recordsLinked to original sources
PubMed2006

Source analysis of epileptic discharges using multiple signal classification analysis.

Multiple signal classification is an alternative to the traditional dipole fitting source analysis methods. Our aim was to assess the clinical usefulness of this algorithm and to compare the localization of the epileptiform electroencephalography discharges with the regions of altered cerebral blood flow in 10 patients with complex partial seizures undergoing preoperative investigation. We performed multiple signal classification analysis of ictal and interictal discharges, and registered single-photon emission computed tomography. Localization of the ictal, but not the interictal discharges, as determined by multiple signal classification analysis was consistent with the regions showing perfusion changes on the single-photon emission computed tomography. Multiple signal classification analysis is a promising tool in localizing foci in patients with complex partial seizures and may contribute to the preoperative evaluation.

Adult↗
PubMed2005

The effect of sleep deprivation on median nerve somatosensory evoked potentials.

The purpose of the study was to determine the effect of one night's sleep deprivation on the early and middle-latency median nerve (MN) somatosensory evoked potentials (SEPs). In 20 healthy volunteers, SEPs in response to electrical stimulation of the MN at the wrist were recorded for the 100-ms post-stimulus period, before and after one night of sleep deprivation. The P14 latency was significantly prolonged after sleep deprivation. We found significant increases in the amplitudes of the early parietal (N20-P24) and the frontal middle-latency (P45-N60) components following sleep deprivation. Our results indicate that somatosensory processing is altered after sleep deprivation.

Adult↗
PubMed2005

[Chronic inflammatory polyneuropathies].

There is an increasing number of peripheral nerve disorders with inflammatory and immune mechanisms involved. The precise diagnosis is of utmost importance, since these patients can be successfully treated. Unfortunately, there is no specific marker for any disease of this group. The diagnosis therefore relies on the appropriate consideration of the clinical, neurophysiological and laboratory data, which requires in-depth knowledge of these diseases. In this paper we review the diagnostic criteria and treatment strategies for the major types of chronic inflammatory polyneuropathies.

Diagnosis, Differential↗
PubMed2003

Perceptual categorization is impaired in Huntington's disease: an electrophysiological study.

Recent evidence raised the possibility that the neostriatum and the corticostriatal circuits could play an important role in semantic categorization. In this study, we examined the electrophysiological correlates of natural scene categorization in Huntington's disease (HD) patients and their asymptomatic relatives who were Huntington's disease mutation carriers (HDC). Event-related potentials were recorded in HD patients, HDC subjects, and age-matched control subjects using a natural scene categorization task. The subjects had to decide whether a briefly presented image contained animals or no animals. Concerning the N1 component (150-250 ms), the mean amplitudes were more negative for nonanimal scenes as compared with stimuli containing animals at all electrode sites in the control group and at all but the lateral temporal electrode sites (T3, T4) in the HD group. Between-group comparison demonstrated that the N1 amplitudes were significantly smaller for both kinds of stimuli in the HD group in spite of a normal primary occipital component (P100). The HDC subjects were not significantly different from the controls concerning the N1 amplitudes. These results suggest that perceptual (N1) processes related to the categorization of natural scenes are specifically impaired in HD. The findings are in agreement with the hypothesis emphasizing the importance of neostriatal mechanisms in human categorization functions.

Adult↗
PubMed2002

Somatosensory evoked potentials correlate with genetics in Huntington's disease.

Abnormalities of somatosensory evoked potentials (SEPs) have been reported in Huntington's disease, a neuropsychiatric disorder caused by the expansion of a CAG trinucleotide repeat. The aim of our study was to determine the relationship between these electrophysiological changes and the length of the nucleotide repeat. We found a striking correlation between the decrease in the early component amplitudes (N20 and N30) of the median nerve SEP and the repeat length, suggesting that these SEP alterations are indeed related to the genetically determined pathological process. The cortical components of the tibial nerve SEP exhibited a dramatic alteration in the patient group and were the only SEP changes found in the group of asymptomatic carriers of the mutation, being more sensitive than the median nerve SEPs.

Adolescent↗
PubMed2002

Complex hallucinations following occipital lobe damage.

Visual hallucinations may accompany many neurological and psychiatric disorders. A common localization principle is that lesions to the early sensory cortices lead to elementary hallucinations, whereas complex perceptual experiences are related to the pathology of higher-level cortical regions. We report the case of a patient who experienced complex, non-stereotyped, multimodal (visual and somatosensory) hallucinations following an acute ischaemic vascular lesion in the right medial occipital lobe. This illustrates that the phenomenology of hallucinations not necessarily reflects the exact localization of cerebral pathology. Instead, the damaged area may serve as a focus of an abnormally activated neuronal network.

Aged↗
PubMed2002

Dissociation between attentional set shifting and habit learning: a longitudinal case study.

We report a patient (ST) with predominant damage to the right neostriatum, caused by a rare cerebral angiitis. The testing procedure was focused on attentional set shifting (Wisconsin Card Sorting Test; WCST) and habit learning (probabilistic classification learning; PCL). ST showed impairments in the WCST, digit span backward, alphabet span, and PCL procedures, whereas he exhibited spared IQ, short-term verbal memory, object recognition, episodic and semantic memory. After 1 month of steroid therapy, there was a significant improvement in the WCST, digit span backward and alphabet span tests, whereas PCL remained severely impaired. The three control patients with damage to the parietal lobe displayed normal learning rates in PCL. These results suggest that separate frontostriatal mechanisms exist for attentional set shifting and habit learning.

Adult↗