Age Group Comparisons of TENS Response Among Individuals With Chronic Axial Low Back Pain.
Chronic low back pain (CLBP) is a highly prevalent and disabling musculoskeletal pain condition among older adults. Transcutaneous electrical nerve stimulation (TENS) is commonly used to treat CLBP, however response to TENS in older adults compared with younger adults is untested. In a dose-response study stratified by age, 60 participants with axial CLBP (20 young, 20 middle-aged, 20 older) received four 20-minute sessions of high-frequency high-intensity TENS over a 2- to 3-week period in a laboratory-controlled setting. Experimental measures of pain sensitivity (mechanical pressure pain detection threshold) and central pain excitability (phasic heat temporal summation and heat aftersensations) were assessed before and after TENS. Episodic or immediate axial CLBP relief was assessed after TENS via measures of resting pain, movement-evoked-pain, and self-reported disability. Cumulative or prolonged axial CLBP relief was assessed by comparing daily pain reports across sessions. Independent of age, individuals experienced episodic increase in the pressure pain detection threshold and reduction in aftersensation after TENS application. Similarly, all groups, on average, experienced episodic axial CLBP relief via improved resting pain, movement-evoked pain, and disability report. Under this design, no cumulative effect was observed as daily pain did not improve for any age group across the 4 sessions. However, older adults received higher TENS amplitude across all sessions to achieve TENS responses similar to those in younger adults. These findings suggest that older adults experience similar episodic axial CLBP relief to that of younger individuals after high-frequency, high-intensity TENS when higher dose parameters are used.


CONCLUSIONS
This study examined age group differences in experimental and axial CLBP response to TENS, delivered under the current recommended parameters of strong, but tolerable amplitude. Older adults had comparable TENS response although at higher TENS amplitude than younger adults, which may have important mechanistic and clinical implications.
Department of Physical Therapy, College of Public Health and Health Professions, University of Florida, Gainesville, Florida; Pain Research & Intervention Center of Excellence, University of Florida, Gainesville, Florida. Electronic address: coreysimon@phhp.ufl.edu.
Corey B
CB
Simon
Pain Research & Intervention Center of Excellence, University of Florida, Gainesville, Florida.
Joseph L
JL
Riley
Pain Research & Intervention Center of Excellence, University of Florida, Gainesville, Florida.
Roger B
RB
Fillingim
Department of Physical Therapy, College of Public Health and Health Professions, University of Florida, Gainesville, Florida; Pain Research & Intervention Center of Excellence, University of Florida, Gainesville, Florida.
Mark D
MD
Bishop
Department of Physical Therapy, College of Public Health and Health Professions, University of Florida, Gainesville, Florida; Pain Research & Intervention Center of Excellence, University of Florida, Gainesville, Florida.
Steven Z
SZ
George
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D059350:Chronic Pain / Q000628:therapy*; D006233:Persons with Disabilities; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D059408:Pain Management / Q000379:methods*; D010147:Pain Measurement; D017288:Pain Threshold; D011312:Pressure; D057566:Self Report; D004561:Transcutaneous Electric Nerve Stimulation
Age; axial; low back pain; transcutaneous electrical nerve stimulation