My short answer is I would agree with the premise of the question that the hearing aid wouldn't be transmitting, communicating, providing access to the World Wide Web or other.... I suppose there are some medical devices like a heart halter that might be transmitting data to a recipient computer, but it's not providing access to the Internet or other digital networks in the sense that it would provide the offender with the ability to access or communicate with a child or access illicit material such as child pornography. But I certainly appreciate the concerns expressed here. I will undertake to go back and see if I can provide a more fulsome answer that would allay the concerns you had identified.
As to the other part of your question, my understanding from reading a lot of case law is I have not seen a sentencing court express concern on how to identify what they want to prohibit a convicted person from accessing. Typically what they do, the way it's reflected in judgments, is a sentencing report is provided to the court and submissions are made by the crown and the defence to provide or restrict access to whatever devices or under what terms of supervision. The intention with Bill C-54 was to leave that flexibility in the hands of the court to craft an appropriate sentence to address the concerns in that case.