Where, as above, C is annuity payment, PV is principal, n is number of payments, starting at end of first period, and i is interest rate per period. Equivalently C is the periodic loan repayment for a loan of PV extending over n periods at interest rate, i.
Refractory epilepsy is a seizure disorder that resists drug treatment. There is some debate among clinicians and researchers about how to define refractory epilepsy. As a result, this term is used in a variety of ways, and when a patient's epilepsy is described as refractory, resistant, or nonresponsive, it can be advisable to ask for more detail about what the diagnosis means.
hard or impossible to manage; stubbornly disobedient: a refractory child. 2. resisting ordinary methods of treatment. 3. difficult to fuse, reduce, or work, as an ore or metal. noun, plural refractories.