Abstract
We have developed a pen and writing tablet for use by subjects during fMRI scanning. The pen consists of two jacketed, multi-mode optical fibers routed to the tip of a hollowed-out ball-point pen. The pen has been further modified by addition of a plastic plate to maintain a perpendicular pen-tablet orientation. The tablet is simply a non-metallic frame holding a paper print of continuously varying color gradients. The optical fibers are routed out of the MRI bore to a light-tight box in an adjacent control room. Within the box, light from a high intensity LED is coupled into one of the fibers, while the other fiber abuts a color sensor. Light from the LED exits the pen tip, illuminating a small spot on the tablet, and the resulting reflected light is routed to the color sensor. Given a lookup table of position for each color on the tablet, the coordinates of the pen on the tablet may be displayed and digitized in real-time. While simple and inexpensive, the system achieves sufficient resolution to grade writing tasks testing dysgraphic and dyslexic phenomena.
Highlights
A functioning writing and reading brain requires a system of language-related neural components to be well-connected and integrated
As implemented for lexical tasks in fMRI experiments, a photometer was placed in the corner of the display of a stimulus computer running E-Prime(R), and the LabVIEW software running on a separate, data collection computer waited for this photometer signal to trigger the start of a trial
“Two subjects” motion was assessed while they performed a reading task (13 min) and a writing task using our pen (13 min) inside the scanner
Summary
A functioning writing and reading brain requires a system of language-related neural components to be well-connected and integrated. The long term goal of this project is to understand the neural substrates responsible for the writing/reading brain in children with learning disability As part of this project, we developed a device for recording handwriting during an fMRI task in children with dysgraphia and dyslexia so that behavior and brain function can be assessed in the same writing-task session. Zakzanis et al [5] custom-built an fMRI-compatible writing device for investigation of the cerebral correlates of a neuropsychological assessment called the Trail Making Test. For many studies of dyslexia/dysgraphia, fine resolution is less centrally important than the ability to qualitatively grade responses and correlate them with brain activation, and a very simple, inexpensive system suffices Such a system using a color map for pen localization is described, allowing the recording of written strokes as they occur in real time.
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