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Hilderley AJ, Taylor MJ, Fehlings D, Chen JL, Wright FV. Optimization of fMRI methods to determine laterality of cortical activation during ankle movements of children with unilateral cerebral palsy. Int J Dev Neurosci 2018; 66:54-62. [PMID: 29413879 DOI: 10.1016/j.ijdevneu.2018.01.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 01/20/2018] [Accepted: 01/22/2018] [Indexed: 10/18/2022] Open
Abstract
Measurement of laterality of motor cortical activations may provide valuable information about lower limb control in children with unilateral cerebral palsy (UCP). Evidence from upper limb research suggests that increased contralateral activity may accompany functional gains. However, lower limb areas of activation and associated changes have been underexplored due to challenges with imaging motor cortical leg representations. In this study, methods for a task-based functional magnetic resonance imaging (fMRI) ankle dorsiflexion paradigm were refined with three pilot groups of participants: (i) adults (n = 5); (ii) typically developing (TD) children (n = 5) and; (iii) children with UCP (n = 4). Parameters of experimental design, task resistance, reproducibility, and pre-scan procedures were tested/refined using a staged development approach with additions or changes introduced if image quality did not meet pre-defined standards. When image quality was acceptable for two consecutive participants, the next participant group was recruited to test/refine the next parameter. The final paradigm involved an event-related design of a single dorsiflexion movement against individualized resistance, with two runs per leg. It included a pre-scan session to increase child comfort and determine task resistance. This paradigm produced valid data for laterality index (LI) calculations to determine the ratio of activity in each hemisphere. Ventricle and lesion masks were used in non-linear image registration, and individual thresholds were used for extent-based LI calculations. LI of dominant ankle movements were contralateral (LI ≥ +0.2) for TD children (mean LI = +0.89, std = 0.27) and children with UCP (mean LI = +0.86, std = 0.26). For the affected ankle of children with UCP, LI values indicated ipsilateral and/or contralateral activation (mean LI = +0.02, std = 0.71, range -0.92 to +1.00). This fMRI paradigm will support investigations of cortical activation and mechanisms of skill improvement following lower limb interventions.
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Affiliation(s)
- A J Hilderley
- Bloorview Research Institute, Holland Bloorview Kids Rehabilitation Hospital, 150 Kilgour Rd, Toronto, M4K 1E1, Canada; Rehabilitation Sciences Institute, University of Toronto, 500 University Ave, Toronto, M5G 1V7, Canada.
| | - M J Taylor
- Diagnostic Imaging, Hospital for Sick Children, 555 University Avenue, Toronto, M5G 1X8, Canada; Department of Medical Imaging, University of Toronto, 263 McCaul Street, Toronto, M5T 1W7, Canada; Department of Psychology, University of Toronto, 100 St. George Street, Toronto, M5S 3G3, Canada.
| | - D Fehlings
- Bloorview Research Institute, Holland Bloorview Kids Rehabilitation Hospital, 150 Kilgour Rd, Toronto, M4K 1E1, Canada; Rehabilitation Sciences Institute, University of Toronto, 500 University Ave, Toronto, M5G 1V7, Canada; Department of Developmental Paediatrics, University of Toronto, 1 King's College Circle, Toronto, M5S 1A8, Canada.
| | - J L Chen
- Rehabilitation Sciences Institute, University of Toronto, 500 University Ave, Toronto, M5G 1V7, Canada; Hurvitz Brain Sciences Program, Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, 2075 Bayview Ave, Toronto, M4N 3M5, Canada; Department of Physical Therapy, University of Toronto, 500 University Ave, Toronto, M5G 1V7, Canada.
| | - F V Wright
- Bloorview Research Institute, Holland Bloorview Kids Rehabilitation Hospital, 150 Kilgour Rd, Toronto, M4K 1E1, Canada; Rehabilitation Sciences Institute, University of Toronto, 500 University Ave, Toronto, M5G 1V7, Canada; Department of Physical Therapy, University of Toronto, 500 University Ave, Toronto, M5G 1V7, Canada.
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