Successful Presurgical Motor Mapping Using Transcranial Magnetic Stimulation in an Eight-Week-Old Infant
Abstract number :
1.166
Submission category :
3. Neurophysiology / 3E. Brain Stimulation
Year :
2021
Submission ID :
1826545
Source :
www.aesnet.org
Presentation date :
12/9/2021 12:00:00 PM
Published date :
Nov 22, 2021, 06:55 AM
Authors :
Shalini Narayana, PhD - University of Tennessee Health Science Center, Le Bonheur Children's Hospital, Memphis TN; Savannah K. Gibbs, BS – Adv Neurosciences Tech, Le Bonheur Children's Hospital; Marianna Rivas-Coppola – University of Tennessee Health Science Center, Le Bonheur Children's Hospital, Memphis TN; Amy McGregor – University of Tennessee Health Science Center, Le Bonheur Children's Hospital, Memphis TN; Asim Choudhri – University of Tennessee Health Science Center, Le Bonheur Children's Hospital, Memphis TN; Adeel Siddiqui – University of Tennessee Health Science Center, Le Bonheur Children's Hospital, Memphis TN; Frederick Boop – Le Bonheur Children's Hospital Neuroscience Institute and University of Tennessee Health Science Center at Memphis
Rationale: Presurgical mapping of motor cortex is critical to surgical planning and minimization of post-operative deficits in pediatric patients. Transcranial magnetic stimulation (TMS), unlike other noninvasive methods, does not require sedation and directly evaluates motor pathways. Here we report the successful use of TMS to identify motor cortex in an 8-week-old infant.
Methods: In a retrospective chart review, we extracted the demographic and clinical information on this infant as well as details of the TMS motor mapping procedure.
Results: Clinical Presentation
A previously healthy 8-week-old female presented to our institution with episodes of bilateral arm stiffening with possible behavioral arrest. EEG showed focal seizures originating from the left frontotemporal head region and infantile spasms. MRI revealed focal cortical dysplasia of the left inferior and middle frontal gyri. Magnetoencephalography during natural sleep localized interictal epileptiform discharges to the left inferior frontal and perisylvian regions; sensory mapping could not be performed without sedation and was deferred. Functional MRI was likewise deferred.
TMS
TMS was performed at 100% of stimulator output with an average E-field of 285 V/m. With the patient seated on a parent’s lap, single pulses of TMS were applied to the left primary motor cortex while recording EMG from the contralateral brachioradialis and flexor carpi radialis. The patient was encouraged to facilitate these muscles by triggering the palmar grasp reflex.
Motor mapping of the lesioned hemisphere hand area was successful in this patient. Ninety-five pulses were applied in total; sixteen produced a motor evoked potential (MEP) and/or cortical silent period. The patient tolerated the procedure well and had no adverse events. Primary motor cortex was shown to be posterior to the lesion (see Fig. 1).
Clinical Outcome
The patient returned at age 8 months due to intractable focal seizures for functional MRI and subsequent microsurgical left frontal topectomy with electrocorticography. fMRI at that time was consistent with TMS at 8 weeks (see Fig. 2). The patient had no post-operative deficits and has been seizure-free through 1.5-year follow up.
Conclusions: This case report exhibits the feasibility of presurgical motor mapping using TMS in infants. To our knowledge, this is the youngest successful TMS mapping to date. Our findings aided in surgical planning and in educating the family about the risks of surgical intervention. Consistent with our expectations, the patient had no motor deficits following surgery. This case illustrates the use of TMS as a safe, noninvasive tool for mapping motor cortex in awake infants.
Funding: Please list any funding that was received in support of this abstract.: none.
Neurophysiology