One popular question is what is meant by "carryover pain relief"?   This is most often asked when one is deciding whether a tens unit or an interferential unit is the most appropriate treatment option. 
There is a distinct difference between the two and the results for the patient


   A tens unit delivers basically 150 pulses per second while an interferential unit delivers 8,000 to 8,150 pulses per second.  A tens unit can be worn 24/7 without any worries of "overdosing" on electricity.  The tens unit is worn because the patient is in pain and continues to be in pain if the unit is turned off.  We tell patients that if the pain returns after turning the tens unit off then turn it back on, even if in bed and not able to sleep due to pain then wear it all night.   This instant recurrence of pain when the tens unit is turned off for many patients is not desirable.

  Historically an interferential treatment was done only in a clinic since there were not any portable units that could deliver the necessary energy of 8,000 pulses per second from a limited portable battery source.  In the clinic the patient would receive a 20 minute treatment session of interferential and upon completion of the treatment the pain was gone.  That absence of pain is what is called the "carryover effect" of interferential treatment.  The duration of the pain free time after treatment would be generally measured in days or possibly weeks.   The carryover effect is what made interferential therapy the most desired form of electrotherapy for chronic pain such as diabetic neuropathy. 

   With the introduction of the Infrex+ unit the patient can now do both tens, as well as interferential when needed.  The treatment time for the interferential mode of the Infrex+ should be to start and do a 20 - 30 minute treatment and then turn the unit off and see if not pain free.  We always recommend using the AC adaptor so the unit can be plugged into an electrical outlet when possible.   The amount of amplitude, another term for power, is determined by the comfort level of the patient.  The power is turned up until the patient feels no pain and then left there for the treatment duration unless the pain returns during the treatment and if so then increase the power until comfort is achieved.  With the Infrex+ in the interferential mode the patient should be able to complete the treatment and be pain free, or as we say have "carryover" pain relief.