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Showing posts with label Latency and Amplitude change. Show all posts
Showing posts with label Latency and Amplitude change. Show all posts

Thursday, August 6, 2009

New on PubMed:

Investigation of the regeneration potential of the recurrent laryngeal nerve (RLN) after compression injury, using neuromonitoring.

Department of General and Visceral Surgery, Hospital of the Johannes Gutenberg-University Mainz, Langenbeckstr. 1, D-55131, Mainz, Germany. moskalenko@tut.by

INTRODUCTION:

The aim of this study was to investigate the regeneration potential of RLN after the compression of the nerve, without disrupting its continuity, using neuromonitoring.

METHODS: In the first operation, the RLN and nervus vagus of adult Goettingen minipigs were dissected free, and the neuromonitoring parameters (amplitude, threshold and lag time of signal) were measured. Injury of the RLN was induced using a "bulldog" clamp. When the signal was no longer detectable, after the 15 min regeneration phase, the operation was finished. The neuromonitoring studies (see above) were repeated in a second operation 6 months later. RESULTS: (1) After the first operation, acute clamping of the RLN led to a reduction in the amplitude of the neuromonitoring signal; the lag time and the threshold of signal remained. Complete restitution of the signal was observed during the first regeneration phase. Repeated clamping led to complete disappearance of the signal. (2) During the second operation, i.e., after 6 months of regeneration, the neuromonitoring signals of both RLN and nervus vagus were detected in 93% of the GMP. No statistical differences (p = 0.17) were noticed between the amplitude of the RLN before the nerve injury (first operation) and after nerve regeneration (second operation). A significant increase in the lag time (p <>

PMID: 18751999 [PubMed - indexed for MEDLINE]

Monday, December 1, 2008

Wave P300 (ERP) & Temporal Lobe Epilepsey







Attention impairment in temporal lobe epilepsy: A neurophysiological approach via analysis of the P300 wave.
Bocquillon PDujardin KBetrouni NPhalempin VHoudayer EBourriez JLDerambure PSzurhaj W.
Department of Clinical Neurophysiology, Lille University Medical Center, Lille, France.
Purpose:
Attention is often impaired in temporal lobe epilepsy (TLE). The P300 wave (an endogenous, event-related potential) is a correlate of attention which is usually recorded during an "oddball paradigm," where the subject is instructed to detect an infrequent target stimulus presented amongst frequent, standard stimuli.
Modifications of the P300 wave's latency and amplitude in TLE have been suggested, but it is still not known whether the source regions also differ. Our hypothesis was that temporal lobe dysfunction would modify the P3 source regions in TLE patients. Methods: A comparative, high density, 128-channel electroencephalographic analysis of the characteristics of P300 (P3b latency and amplitude) was performed in 10 TLE patients and 10 healthy controls during auditory and visual oddball paradigms. The P3b sources were localized on individual 3D MR images using the LORETA method and intergroup statistical comparisons were performed using SPM2(R) software. Results: Our main results (in both individual analyses and intergroup comparisons) revealed a reduction in temporal (and more particularly mesiotemporal) sources and, to a lesser extent, frontal sources in TLE patients, compared with controls. Discussion: This reduction may reflect direct, local cortical dysfunction caused by the epileptic focus or more complex interference between epileptic networks and normal attentional pathways. Hum Brain Mapp, 2009. (c) 2008 Wiley-Liss, Inc.

PMID: 19034898 [PubMed - as supplied by publisher]