1. Cortical excitability changes after paediatric mild traumatic brain injury: Preliminary data
Seeger TA, Kirton CA, Barlow KM 
Traumatic brain injury (TBI) occurs in between per 100,000 people every year1–3.
Mild TBI (mTBI) accounts for 70-90% of all TBI.
The highest risk ages for TBI-related emergency department visits are during infancy and adolescence4.
TBI is associated with changes in neurotransmitter function5,6, electroencephalography7–9, tractography imaging10, and other pathologies11–14.
Transcranial magnetic stimulation (TMS) is a non-invasive brain stimulation technique that uses magnetic fluctuation to painlessly induce changes in potentials of neurons15,16
TMS has been found safe in healthy children17–19.
Responses to TMS paradigms are altered after TBI in adults, but have yet to be studied in children with TBI.
To explore the tolerability of TMS after mTBI in children.
Single pulse and paired pulse paradigms were given to children 8-18 years of age using standard protocols (Figure 1)
Children were recruited as part of the Play Game Trial and presented at the Alberta Children’s Hospital after mTBI.
Children were excluded if there was any indications of TMS being above minimal risk in that child
TMS was given one month after injury, and given to uninjured healthy controls
After TMS sessions (1 hour), participants filled out a tolerability questionnaire, rating TMS relative to other age-appropriate activities, and subjectively rated mild adverse events.
Background
Transcranial magnetic stimulation tolerability comparisons
Figure 1: Above, a participant is seated in the chair, watching a movie during the transcranial magnetic stimulation procedure. Left is a diagram approximating the primary pathway that a stimulus will travel to reach the hands
Objective
Methods
Figure 2: Means and standard deviations of tolerability scores from standardized form used to compare transcranial magnetic stimulation session with 7 other activities that children are likely to participate in and be familiar with. Lower scores indicate a greater enjoyment of the activity listed.
9 mTBI participants and 4 healthy controls filled out the questionnaire.
No severe adverse events occurred during sessions.
Follow ups and consistent contact showed no other adverse events outside of sessions for all groups
Demographic data:
Ages at appointment were normally distributed (Shapiro-Wilks) for all groups (p = ), and not different between groups, F(2, 10) = 0.59, p = 0.943
Genders were split (male:female) as 1:3 in healthy controls, 3:1 in asymptomatic, and 2:3 in symptomatic participants, χ2 (2) = 2.14, p = (Pearson’s Chi-Square)
Tolerability:
Non normal distribution only for symptomatic children (p = 0.046), but not for asymptomatic (p = 0.850) or healthy controls (p = 0.850).
2 mild cases of tingling in symptomatic group, 1 mild case of tingling in asymptomatic group (Figure 3).
Median rank for TMS by the symptomatic group was 4 (mean ± standard deviation; 4.60 ± 0.89), the median rank of the asymptomatic group was 4 (4.75 ± 1.71) and the median rank for TMS in the control group was 5.5 (5.25 ± 1.71), Figure 2.
No difference between groups for TMS ranking, χ2 (8) = 6.12, p = 0.634
Despite reporting mild tingling, the mTBI group may find TMS more enjoyable than controls. This may be due to enhanced feelings of altruism for future mTBI patients.
Results
Frequency of mild adverse events during transcranial magnetic stimulation
Conclusions
References
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Figure 3: Frequencies of the reported mild adverse events experienced by participants from the three groups, healthy controls, and asymptomatic and symptomatic mild traumatic brain injury participants, one month after injury, when given single and paired pulse transcranial magnetic stimuli under standard protocols