Bilateral Motor Responses to Transcranial Magnetic Stimulation in Preterm Children at 9 Years of Age

2021 ◽  
Author(s):  
A. Marita Valkama ◽  
Seppo O. Rytky ◽  
Päivi M. Olsén
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Corticospinal Tract ◽  
Motor Evoked Potentials ◽  
Abductor Pollicis Brevis ◽  
Motor Responses ◽  
Motor Disability ◽  
Motor Tracts ◽  
Preterm Born ◽  
Muscle Responses

Abstract Objective This study was aimed to evaluate motor tracts integrity in nondisabled preterm-born (PT) children at 9 years of age. Methods Overall, 18 PT and 13 term-born (T) children without motor disability were assessed by transcranial magnetic stimulation (TMS). Motor-evoked potentials (MEPs) were measured bilaterally from the abductor pollicis brevis (APB) and the tibialis anterior (TA) muscles. Muscle responses could be stimulated from all patients. Results Overall, 83.3 and 23.1% of PT and T children, respectively, had mild clumsiness (p = 0.001). One PT and three T children had immediate bilateral responses in the upper extremities. Seven PT children had delayed ipsilateral APB responses after left and ten after right TMS. Three controls had delayed ipsilateral responses. Ipsilateral lower extremity responses were seen in one PT after right and two PT children and one T child after left TMS. The results did not correlate to groups, genders, clumsiness, or handedness. Conclusion Children of PT and T may have bilateral motor responses after TMS at 9 years of age. Ipsilateral conduction emerges immediately or more often slightly delayed and more frequently in upper than in lower extremities. Significance Bilateral motor conduction reflects developmental and neurophysiological variability in children at 9 years of age. MEPs can be used as a measure of corticospinal tract integrity in PT children.

High-intensity, low-frequency repetitive transcranial magnetic stimulation enhances excitability of the human corticospinal pathway

2020 ◽  
Vol 123 (5) ◽  
pp. 1969-1978
Author(s):  
Jessica M. D’Amico ◽  
Siobhan C. Dongés ◽  
Janet L. Taylor
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
High Intensity ◽  
Magnetic Stimulation ◽  
Corticospinal Tract ◽  
Motor Evoked Potentials ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Low Frequency ◽  
Intracortical Inhibition ◽  
Corticospinal Pathway ◽  
Plastic Changes

In this study, we present a novel, intensity-dependent repetitive transcranial magnetic stimulation (rTMS) protocol that induces lasting, plastic changes within the corticospinal tract. High-intensity rTMS at a frequency of 0.1 Hz induces facilitation of motor evoked potentials (MEPs) lasting at least 35 min. Additionally, these changes are not limited only to small MEPs but occur throughout the recruitment curve. Finally, facilitation of MEPs following high-intensity rTMS does not appear to be due to changes in intracortical inhibition or facilitation.

The Effect of Etomidate on Motor Evoked Potentials Induced by Transcranial Magnetic Stimulation in the Monkey

Neurosurgery ◽  
1990 ◽  
Vol 27 (6) ◽  
pp. 936-942 ◽  
Author(s):  
Ramsis F. Ghaly ◽  
James L. Stone ◽  
Walter J. Levy ◽  
Peter Roccaforte ◽  
Edward B. Brunner
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Evoked Potentials ◽  
Total Dose ◽  
Magnetic Stimulation ◽  
Motor Evoked Potentials ◽  
Mean Amplitude ◽  
Abductor Hallucis ◽  
Abductor Pollicis Brevis ◽  
Hypnotic Agent ◽  
The Mean

Abstract Etomidate (ET) is a known hypnotic agent in neuroanesthesia. This study was designed to examine the reliability of motor evoked potentials (MEPs) after transcranial magnetic stimulation in monkeys anesthetized intravenously with ET. The ET regimen was as follows: an initial dose (0.5 mg/kg) followed by 13 doses (0.2 mg/kg every 6-12 min; mean, 8.0 ± 1.3 min). The total dose administered was 3.1 mg/kg. The magnetic coil was placed over the MEP scalp stimulation region. Evoked electromyographic responses were recorded from the contralateral abductor pollicis brevis (APB) and abductor hallucis (AH) muscles of the fore- and hindlimbs, respectively. Reproducible MEP responses were consistently recorded while the animal was under total ET anesthesia. The coil demography was altered and the MEP scalp topography was moderately reduced by ET injections. Significant threshold elevation was noted after a total dose of 1.7 mg/kg for APB responses and 0.5 mg/kg for AH responses (P < 0.05). Marked prolongation of latency was observed after a dose of 0.5 mg/kg for APB MEPs and 2.5 mg/kg for AH MEPs (P < 0.05). MEP amplitude responses showed marked variability. Repeated doses of ET produced a mean threshold rise of 14 to 28% for the APB and 19 to 29% for the AH. The mean latency delay was 5 to 11% for the APB and 0.5 to 8% for the AH, while the mean amplitude depression was 24 to 59% for the APB and 15 to 50% for the AH. Apparent seizure activity or abnormalities in behavior and feeding were not noted over a 1-year period. We conclude that monitoring of MEPs induced by transcranial magnetic stimulation under ET anesthesia is feasible. Clear MEP responses can be maintained under ET anesthesia. ET caused alterations in MEPs induced by transcranial magnetic stimulation, and awareness of such changes is important. Further investigation in humans is recommended.

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.

Locating and Outlining the Cortical Motor Representation Areas of Facial Muscles With Navigated Transcranial Magnetic Stimulation

Neurosurgery ◽  
2015 ◽  
Vol 77 (3) ◽  
pp. 394-405 ◽  
Author(s):  
Laura Säisänen ◽  
Petro Julkunen ◽  
Samuli Kemppainen ◽  
Nils Danner ◽  
Arto Immonen ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Motor Cortex ◽  
Evoked Potentials ◽  
Magnetic Stimulation ◽  
Motor Evoked Potentials ◽  
Navigated Transcranial Magnetic Stimulation ◽  
Tumor Patients ◽  
Abductor Pollicis Brevis ◽  
Facial Muscles ◽  
Cortical Motor

Abstract BACKGROUND: Navigated transcranial magnetic stimulation (nTMS) has become established as an accurate noninvasive technique for mapping the functional motor cortex for the representation areas of upper and lower limb muscles but not yet for facial musculature. OBJECTIVE: To characterize the applicability and clinical impact of using nTMS to map cortical motor areas of facial muscles in healthy volunteers and neurosurgical tumor patients. METHODS: Eight healthy volunteers and 12 patients with tumor were studied. The motor threshold (MT) was determined for the abductor pollicis brevis and mentalis muscles. The lateral part of the motor cortex was mapped with suprathreshold stimulation intensity, and motor evoked potentials were recorded from several facial muscles. The patient protocol was modified according to the clinical indication. RESULTS: In all healthy subjects, motor evoked potentials were elicited in the mentalis (mean latency, 13.4 milliseconds) and orbicularis oris (mean latency, 12.6 milliseconds) muscles. At 110% of MT of the mentalis, the motor evoked potentials of facial muscles were elicited mainly in the precentral gyrus but also from one gyrus anterior and posterior to it. The cortical areas applicable for mapping were limited by an artifact attributable to direct peripheral nerve stimulation. The mapping protocol was successful in 10 of 12 tumor patients at locating the representation area of the lower facial muscles. The MT of the facial muscles was significantly higher than that of the abductor pollicis brevis. CONCLUSION: nTMS is an applicable and clinically beneficial noninvasive method to preoperatively map the cortical representation areas of the facial muscles in the lower part of the face. Instead of using the MT of the abductor pollicis brevis, the stimulus intensity during mapping should be proportioned to the MT of a facial muscle.

Treatment of patients with cervical and upper thoracic incomplete spinal cord injury using repetitive transcranial magnetic stimulation

2019 ◽  
Vol 43 (5) ◽  
pp. 323-331
Author(s):  
Katarzyna Leszczyńska ◽  
Agnieszka Wincek ◽  
Wojciech Fortuna ◽  
Juliusz Huber ◽  
Jagoda Łukaszek ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Transcranial Magnetic Stimulation ◽  
Surface Electromyography ◽  
Magnetic Stimulation ◽  
Motor Evoked Potentials ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Incomplete Spinal Cord Injury ◽  
Abductor Pollicis Brevis ◽  
Cord Injury

Purpose: To evaluate the short- and long-term effectiveness of repetitive transcranial magnetic stimulation with parameters based on results of comparative neurophysiological studies in patients with incomplete spinal cord injury. Results may help to understand mechanisms responsible for regeneration of the incomplete spinal cord after injury. Methods: Repetitive transcranial magnetic stimulation sessions (three to five sessions per month for not less than 5 months) to 15 patients with C4-Th2 incomplete spinal cord injury were applied with individually designed parameters. One session consisted of bilateral stimulation of the primary motor cortex (for 10 min each with 800 stimuli in 2-s lasting trains and the inter-train intervals of 28 s) with frequency at 20–22 Hz and stimulus strength that was 70%–80% of the resting motor threshold (0.84–0.96 T). Recordings of surface electromyography at rest and during the attempt of maximal muscle contractions and motor evoked potentials were performed from abductor pollicis brevis and tibialis anterior muscles bilaterally. Amplitude parameters of surface electromyography and motor evoked potentials were used as outcomes. All neurophysiological tests were comparatively applied before and after treatment. Results: Decrease in surface electromyography amplitudes recorded at rest from abductor pollicis brevis (p = 0.009), increase in surface electromyography amplitudes during maximal contraction of abductor pollicis brevis (p = 0.03) and increase in motor evoked potential parameters recorded from abductor pollicis brevis (p = 0.04) were found. Conclusion: Proposed repetitive transcranial magnetic stimulation algorithm reduced the increased muscle tension in upper extremity muscles, improved the function of upper extremity muscle motor units and slightly improved the transmission of efferent neural impulses within spinal pathways. Besides functional recovery in descending spinal pathways, repetitive transcranial magnetic stimulation may also inhibit inevitable pathological changes in nerves.

scholarly journals Reliability of diaphragmatic motor-evoked potentials induced by transcranial magnetic stimulation

2020 ◽  
Vol 129 (6) ◽  
pp. 1393-1404
Author(s):  
Joseph F. Welch ◽  
Patrick J. Argento ◽  
Gordon S. Mitchell ◽  
Emily J. Fox
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Evoked Potentials ◽  
Magnetic Stimulation ◽  
Motor Evoked Potentials ◽  
Surface Emg ◽  
Noninvasive Technique ◽  
Large Variability ◽  
Adult Men ◽  
Latency Duration ◽  
Excellent Reproducibility

Transcranial magnetic stimulation (TMS) is a noninvasive technique to assess neural impulse conduction along the cortico-diaphragmatic pathway. The reliability of diaphragm motor-evoked potentials (MEP) induced by TMS is unknown. Notwithstanding large variability in MEP amplitude, we found good-to-excellent reproducibility of all MEP characteristics (latency, duration, amplitude, and area) both within- and between-day in healthy adult men and women. Our findings support the use of TMS and surface EMG to assess diaphragm activation in humans.

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