Can my employer purchase my hearing aids and use it as a business expense? They are required to perform my job.

Technically yes. Your employer would need to include the amount they paid for your hearing aids on your W-2 as income (per the IRS rules), and then they can take the expense on their business return. 

Does the Corporation or the employee have to pay Social Security and Medicare on this benefit?

If your employer included the amount of the benefit on your W-2 wages, then yes, Social Security and Medicare would be paid on this amount.

 

A fringe benefit is a form of pay for the performance of services, given by the employer to the employee. For example, Personal Use of a Company Car (PUCC), in which you allow the employee to use a business vehicle for personal use, is a type of fringe benefit.

 

Non-cash fringe benefits should ideally be reported on a paycheck where the employee has regular wages to offset the taxes on the fringe benefit items.

 

Click this link for more info on Employee Fringe Benefits.