Representative Edward J. Markey, a Massachusetts Democrat, who wrote recently enacted legislation that will require mobile devices to be more accessible to users with disabilities, said approximately three-fourths of communications and video devices need to be adapted for blind and deaf people. “Apple,” he said in a statement, “is an outlier when it comes to devices that are accessible out of the box.”

The iPad is also, generally speaking, less expensive than computers and other gadgets specifically designed to help disabled people speak, read or write. While insurers usually do not cover the cost of mobile devices like the iPad because they are not medical equipment, in some cases they will pay for the applications that run on them.

In Owen’s case, his grandmother bought him a $600 iPad in August, and his parents have invested about $200 more in software. One day this summer, his finger dangled over the title page of “Alice in Wonderland” on his iPad while his mother hovered over his shoulder in their Brooklyn home. Then, with the tiniest of movements, and thanks to the sensitivity of the iPad’s touch screen, Owen began to turn the pages of the book. “You are reading a book on your own, Owen!” Ms. Goldstein, 44, exclaimed. “That is completely wonderful.”

But while the sensitivity of the iPad’s touch screen makes it promising for Owen, it can be problematic for others, like Glenda Watson Hyatt, a blogger in Surrey, British Columbia, who has cerebral palsy. “When ‘flipping’ screens, sometimes I flip more than one screen,” Ms. Hyatt wrote in an interview conducted by e-mail. “Or I touch what I didn’t intend to.”

Still, Ms. Hyatt said that when she was having trouble chatting with friends at a bar recently, she pulled out her iPad to help communicate and felt normal. “People were drawn to it because it was a ‘recognized’ or ‘known’ piece of technology,” she wrote in a blog post reviewing the device.

At the Shepherd Center, a spinal cord rehabilitation clinic in Atlanta, some teenage quadriplegics have received iPads as gifts, but they do not work well for those who rely on a mouse stick  basically a long pen controlled by mouth.

“It wants to see a finger,” said John Anschutz, the manager of the assistive technology program at Shepherd. “It really requires the quality of skin and body mass to operate.”