Validation of surface recordings of the diaphragm response to transcranial magnetic stimulation in humans

2003 ◽  
Vol 94 (2) ◽  
pp. 453-461 ◽  
Author(s):  
Alexandre Demoule ◽  
Eric Verin ◽  
Chrystèle Locher ◽  
Jean-Philippe Derenne ◽  
Thomas Similowski
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Evoked Potential ◽  
Potential Problem ◽  
Motor Evoked Potentials ◽  
Motor Evoked Potential ◽  
Abdominal Muscles ◽  
Serratus Anterior ◽  
Motor Pathways ◽  
Surface Electrodes

The integrity of the central efferent motor pathways to the diaphragm can be assessed by using transcranial magnetic stimulation to measure the latency of the corresponding motor evoked potentials with surface electrodes. Because transcranial magnetic stimulation does not activate the diaphragm alone, signal contamination is a potential problem. To evaluate this issue, surface diaphragmatic motor-evoked potential latencies were compared with latencies recorded from diaphragm needle in 9 healthy volunteers. Surface latencies of muscles likely to contaminate the diaphragm signals (serratus anterior, pectoralis major, and tranversus abdominis) were also recorded. The latencies in response to nonfocal transcranial stimulation from surface electrodes were not significantly different from the needle ones (17 ± 1.3 vs. 17.2 ± 1.1 ms, respectively) but were significantly different from the latencies of the other muscles. In two cases, signal contamination appeared likely (serratus anterior in 1 case, abdominal muscles in 1 case). It is possible to reliably measure the latency of the diaphragm response to transcranial magnetic stimulation with adequately positioned surface electrodes.

scholarly journals Onset Latency of Motor Evoked Potentials in Motor Cortical Mapping with Neuronavigated Transcranial Magnetic Stimulation

2015 ◽  
Vol 9 (1) ◽  
pp. 62-69 ◽  
Author(s):  
Elisa Kallioniemi ◽  
Minna Pitkänen ◽  
Laura Säisänen ◽  
Petro Julkunen
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Motor Evoked Potentials ◽  
Motor Evoked Potential ◽  
Cortical Mapping ◽  
Abductor Pollicis Brevis ◽  
Motor Pathways ◽  
Motor Mapping ◽  
Cortical Motor ◽  
Abductor Digiti Minimi

Cortical motor mapping in pre-surgical applications can be performed using motor evoked potential (MEP) amplitudes evoked with neuronavigated transcranial magnetic stimulation. The MEP latency, which is a more stable parameter than the MEP amplitude, has not so far been utilized in motor mapping. The latency, however, may provide information about the stress in damaged motor pathways, e.g. compression by tumors, which cannot be observed from the MEP amplitudes. Thus, inclusion of this parameter could add valuable information to the presently used technique of MEP amplitude mapping. In this study, the functional cortical representations of first dorsal interosseous (FDI), abductor pollicis brevis (APB) and abductor digiti minimi (ADM) muscles were mapped in both hemispheres of ten healthy righthanded volunteers. The cortical muscle representations were evaluated by the area and centre of gravity (CoG) by using MEP amplitudes and latencies. As expected, the latency and amplitude CoGs were congruent and were located in the centre of the maps but in a few subjects, instead of a single centre, several loci with short latencies were observed. In conclusion, MEP latencies may be useful in distinguishing the cortical representation areas with the most direct pathways from those pathways with prolonged latencies. However, the potential of latency mapping to identify stressed motor tract connections at the subcortical level will need to be verified in future studies with patients.

Design and analysis of motor-evoked potential data in pediatric neurobehavioral disorder investigations

2012 ◽  
Author(s):  
Donald L. Gilbert
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Research Methods ◽  
Magnetic Stimulation ◽  
Evoked Potential ◽  
Motor Evoked Potential ◽  
Experimental Designs ◽  
Future Research ◽  
Paired Pulse ◽  
Practical Guidance

This article discusses how transcranial magnetic stimulation (TMS) can be used to study the pathophysiological substrata of pediatric neurological and neurobehavioural disorders and to provide practical guidance for future research. It outlines the substantial challenges inherent in studying in vivo the neurobiology of pediatric neurobehavioural disorders, such as safety, quantitative versus categorical measures, and challenges in correlational studies. It discusses ways in which TMS generates quantitative measures that may function as endophenotypes for neurobehavioural disorders. Combining TMS with other modalities may also be informative. Single- and paired-pulse TMS is safe and well tolerated in children. The application of rigorous experimental designs and a combination of TMS with other research methods may increase the knowledge of pathophysiology and treatment of pediatric neurobehavioural disorders.

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