Stability of the cardiovascular response during single-pulse TMS in perinatal stroke

Abstract

Serious adverse events of syncope have been reported with single pulse transcranial magnetic stimulation (sp-TMS) in both healthy adults and adolescents post stroke [3,5,[7][8][9]. Despite these reports, the physiological mechanisms leading to syncope during sp-TMS administration are not clearly understood. A syncopal event is classically identified by a sudden, large reduction in blood supply to neural tissue "cerebral hypoperfusion" to ultimately cause a loss of consciousness [2]. Common symptoms preceding syncope include lightheadedness, nausea, diaphoresis, and/or visual changes. Syncopal events may occur via an irregular autonomic nervous system (ANS) response to emotional or administered stimuli, which is commonly known as neurocardiogenic syncope [2,4]. Neurocardiogenic syncope can result from transient mean arterial pressure (MAP) and heart rate (HR) changes in response to precipitating factors such as anxiety in combination with a mildly noxious, novel stimulus [4]. Although literature is sparse, children with perinatal stroke appear to be at an additional increased risk for autonomic dysfunction [1] and autonomic immaturity in typically-developing pediatric populations increases the risk for neurocardiogenic syncope [4]. We aimed to determine if sp-TMS caused immediate cardiovascular changes in in children and adolescents with congenital hemiparesis due to perinatal stroke.Seven males (12±4 yrs, average±sd) and eight females (14±5 yrs) completed an experimental session as part of a larger clinical trial (). A 70-mm-diameter Magstim figureof-eight coil (Magstim, Whitland, U.K.) with a Magstim 200 2 unit delivered stimulation for

Heart rate and blood pressure responses to corticomotor stimulation in young, healthy adults

“…Based on previous reports of syncope from sp-TMS ( Gillick et al, 2015 ), it may appear that active sp-TMS decreases BP. The lack of reductions in BP and HR with sp-TMS in our study is consistent with our previous work in children with cerebral palsy ( Keller-Ross et al, 2018 ). Although, sp-TMS has been shown to inhibit sympathetic activity ( Macefield et al, 1998 ), which would likely decrease BP, Macefield et al (1998) observed nonsignificant increases in diastolic BP.…”

“…In both the previous study and the current study, these individuals had relatively stable vitals during experimental sessions indicating that the near-syncopal event was not due to direct physiological responses to cortical stimulation. Although the novel stimulus was less likely the case in our previous report ( Keller-Ross et al, 2018 ), it may be a likely cause in the current study as it occurred during initial TMS testing.…”

“…Single-pulse transcranial magnetic stimulation (sp-TMS) is used to measure cortical excitability ( Chen et al, 2016 ). Serious adverse events of syncope have occurred with sp-TMS ( Gillick et al, 2015 , Keller-Ross et al, 2018 ) . One such event is neurocardiogenic syncope ( Gillick et al, 2015 ), which occurs from transient blood pressure (BP) changes in response to precipitating factors such as anxiety in combination with a mild noxious, novel stimulus ( Grubb, 2005 ).…”

“…Previous work investigating the effect of sp-TMS on cardiovascular function has demonstrated equivocal findings. For example, it has been demonstrated that sp-TMS does not alter heart rate (HR) and BP ( Keller-Ross et al, 2018 , Macefield et al, 1998 ), yet sympathetic inhibition has been reported, which could reduce BP. However, most prior reports were not designed primarily to measure direct influences of sp-TMS on BP.…”

“…We recently reported that sp-TMS caused a near-syncopal event in a child with cerebral palsy ( Keller-Ross et al, 2018 ). In both the previous study and the current study, these individuals had relatively stable vitals during experimental sessions indicating that the near-syncopal event was not due to direct physiological responses to cortical stimulation.…”