Just a note – the cellulose sponge may not work with some iPad screen protectors as found by some comments previously shared by readers. Another thought may be to use short styluses (similar to using a short pencil; see references below) which may discourage the occurance of wrapped fingers around a standard sized stylus. Certainly choosing the right device to support the developmental hand skills of the user are in order here. If in question, ask your OT!
Here are inexpensive (8.95 for 9 styluses – no shipping with Prime account :0), Short Stylus Pens available from Amazon that also might help with developing a more refined grasp:
For other styluses or mobile device equipment visit the OT’s with Apps Amazon Store.
Ideas for your OT iTool Kit.
Related articles pertaining to using a short pencil/tool when writing:
Handwriting Strategies – http://teachers.henrico.k12.va.us/exed/ExEdHCPS/OTPT/HandwritingStrategies.pdf
Fine Motor Development – http://www.schoolsparks.com/early-childhood-development/fine-motor