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Mabbott Lab

The speed of thinking study

What is the purpose of this study?

The purpose of this study is to examine the effects of treatment for childhood brain tumours on the growth of the brain and on the ability and speed of thinking. With recent advances in medical treatment, there are currently over 3000 survivors of paediatric brain tumors in Canada. Although we are beginning to deal with the mortality from this disease, we must often accept learning problems as a cost of treatment, particularly for children treated with cranial radiation. Cranial radiation is the only curative treatment for most malignant tumours.

We plan to look at the causes of thinking problems following cranial radiation for paediatric brain tumours. We think that white matter damage that occurs following cranial radiation treatment is directly related to learning problems.  

Dr. Mabbott and Dr. Dockstader are conducting a study using brain imaging to understand how injury to white matter results in learning problems. We will obtain brain scans of white matter as well as of brain function.  In order to make comparisons, tests will be done for healthy children and for children treated with cranial radiation for brain tumours. We think that a better understanding of how white matter damage results in poor thinking skills may lead to improved detection, treatment and hopefully reduction of the learning problems associated with treatment for brain tumours. The information from this study may lead to changes in the treatment for children with tumours in the future. It may also aid in understanding and treating the learning disabilities that these children can experience after treatment.

Who is eligible for this study?

Your child is eligible to participate in the study if he/she:

  • Is between the ages of 5 and 17.
  • Has either English as his or her native language or has had at least two years of schooling in English.   

Your child is not eligible to participate in the study if he/she:

  • Has prior history of traumatic brain injury, neurological disorder, cerebral palsy, developmental delay or learning disability not associated with a brain tumour.
  • Is younger than 5 years of age.
  • Is older than 17 years of age.
  • Requires sedation for brain scanning.  
  • Is claustrophobic, as the brain scanning requires that children enter a tunnel in the MRI machine.  
  • Has any metal parts in their body like a cochlear (ear) implant. The MRI machine uses a large magnet to obtain pictures of the brain. Dental fillings are OK.

What will be required of my child?

  • Your child will participate in a two hour individual testing session at The Hospital for Sick Children (SickKids) during which he/she will participate in two neuroimaging procedures.  
  • For one procedure, your child will have a scan of his/her brain using an MRI. After receiving preparatory training to get them ready to go into the MRI, your child will be asked to lie very still within the MRI scanner for about 30 minutes while scanning is completed. The risks of MRI brain scans are very low. MRI uses radio waves and a strong magnetic field to provide clear and detailed pictures of the brain and other internal organs. These brain scans do not involve radiation.  
  • Your child will also participate in our MEG experiment. MEG (Magnetoencephalography) is a non-invasive procedure that records the brain’s own magnetic fields. MEG is a completely passive technique – it does not pass any fields through the brain. In this experiment, your child will lie still on the MEG bed for 3 minutes. Then he/she will do two visual-motor tasks: one four-minute task and one 8-minute task. Some children may not like lying down in the MRI or MEG machine. If your child becomes upset in either machine, the imaging will be discontinued.  A research assistant will be in the imaging suite with your child at all times during the scanning in order to assist him/her.

How can I find out more?

If you are interested in participating in the study or receiving more information, please contact Cynthia de Medeiros at 416-813-7396 (ext. 307396).  

Thank you.