Motor Evoked Potentials as Potential Biomarkers of Early Atypical Corticospinal Tract Development in Infants with Perinatal Stroke

Abstract

Diagnosis of cerebral palsy (CP) after perinatal stroke is often delayed beyond infancy, a period of rapid neuromotor development with heightened potential for rehabilitation. This study sought to assess whether the presence or absence of motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) could be an early biomarker of atypical development within the first year of life. In 10 infants with perinatal stroke, motor outcome was assessed with a standardized movement assessment. Single-pulse TMS was utilized to assess presence of MEPs. Younger infants (3–6 months CA, n = 5, 4/5 (80%)) were more likely to present with an MEP from the more-affected hemisphere (MAH) compared to older infants (7–12 months CA, n = 5, 0/5, (0%)) (p = 0.048). Atypical movement was demonstrated in the majority of infants with an absent MEP from the MAH (5/6, 83%) compared to those with a present MEP (1/4, 25%) (p = 0.191). We found that age influences the ability to elicit an MEP from the MAH, and motor outcome may be related to MAH MEP absence. Assessment of MEPs in conjunction with current practice of neuroimaging and motor assessments could promote early detection and intervention in infants at risk of CP.

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

“…Combinations of methods increase follow-up possibilities of therapies after disability diagnoses. 11,12,31 The MEP latencies of PT and T children in our series were in line with earlier results of healthy children. 9,19,28 The average CMCT (in ►Table 2) was 6 to 7 ms to upper extremities and 11 to 13 ms to lower extremities, which also is in line with earlier studies and confirms the normality of central motor pathway conduction in our PT children at the age of 9 years.…”

“…To get a more detailed and broader insight into bilateral conduction after TMS in preterm children, the TMS technique should be combined with modern brain neuroimaging. 11,12,31 The possibility to find out later real CDC in preterm children would demand further developmental follow-up.…”

“…7,8 TMS is as a diagnostic tool to follow-up neural recovery after perinatal insults. 4,5,[9][10][11][12] It can be used to assess corticospinal tract connectivity. 3,10,13,14 Aberrant neural network can emerge either from ipsilateral corticospinal tract projecting or from insufficient interhemispheric inhibition.…”

“…15 The sTMS studies evaluating children with cerebral palsy have shown bilateral motor responses after neonatal brain damage. 6,[11][12][13]16 However, sTMS can detect corticospinal tract abnormalities also without apparent parenchymal defects in anatomical neuroimagings. 6 As ipsilateral responses are also found in some normal children, the purpose of this study was to compare functional integration of motor corticospinal tracts at the age of 9 years in functionally healthy preterm-born (PT) children with very low birth weight (birth weight 1,500 g, VLBW) to term-born (T) children by measuring motor nerve conduction to upper and lower extremities after TMS.…”

A novel bone-thinning technique for transcranial stimulation motor-evoked potentials in rats

“…Transcranial electrical stimulation MEP (tcMEP) is currently one of the most popular intraoperative pyramidal tract monitoring methods in clinical neurosurgery 1 , 2 , spinal surgery 3 , 4 , and aortic surgery 5 . Evaluating intraoperative motor function with tcMEPs often provides information on strategies to preserve postoperative motor function and evaluate patients following nerve injury (e.g., stroke or spinal cord injury) 6 – 8 .…”