Table 2.

Review Outcome Measures, Adverse Events, TENS Ratings, and TENS Recommendations.

Year	Topic	Author	Pain Outcome Measures	Movement Evoked Pain	Adverse Event Reported	Rating Positive (+) Negative (−) Equivalent (=) Undecided (u)	TENS Recommendation	Ref
2021	Acute Pain	Davis	Pain scores, not specified	No	Reported no adverse events	(+)	Promising results for patients with hip fractures in the prehospital setting and would benefit from further studies	[80]
2019	Acute Pain	Binny	VAS, NRS	No	Limited data with 2 studies reporting no AE’s.	(u)	Recommended further studies	[53]
2015	Acute Pain	Johnson	VAS, NRS < VRS, MPQ	No	Yes	(+)	While TENS use for acute pain in adults remains a matter of debate, it compares favorably with many alternatives because it is inexpensive, self-administered, safe, and readily available to patients	[1]
2014	Acute Pain	Simpson	VAS	N/A	No safety risks identified	(+)	Emergency medical services should consider TENS when pharmacological pain management is unavailable or restricted.	[81]
2020	Cancer, Neurological	Moisset	HA days per month	No	No	(+)	TENS may be effective for acute migraine HA; larger well-conducted studies are necessary to confirm efficacy	[82]
2020	Cancer, Neurological	Ogle	VAS, NRS, SF-MPQ	No	No	(+)	TENS as a self-management strategy monitored by a clinician may be beneficial in reduction in peripheral neuropathy pain	[83]
2018	Cancer, Neurological	Tao	HA days per month	No	Yes	(+)	TENS may be an effective alternative to reduce monthly HA days. Well-designed RCTs are necessary to confirm and update findings.	[85]
2018	Cancer, Neurological	Amatya	VAS, BPI, NRS	No	No	(u)	Further studies with larger sample sizes	[84]
2017	Cancer, Neurological	Gibson	VAS	No	Three studies reported AE. AEs included skin irritation	(u)	Improve the quality of design of TENS studies	[54]
2015	Cancer, Neurological	Johnson	No Articles to review	No Articles to review	No Articles to review	(u)	No articles to review	[63]
2014	Cancer, Neurological	Bao	VAS, NRS	No	No	(+)	TENS might have beneficial for pain reduction in bone cancer; small sample sizes	[62]
2014	Cancer, Neurological	Jawahar	VAS, McGill Pain Questionnaire	No	No	(+)	TENS may be effective in reducing central neuropathic pain in MS. Recommendations were made for more rigorous design and reporting is needed to determine TENS effectiveness for individuals with MS.	[86]
2021	Chronic Pain	Paley	VAS, Estimated Effect	No	Yes	(+)	Multiple reviews with multiple conditions. TENS has a tendency toward benefit in 16/169 reviews, no benefit in 13/169 reviews and inconclusive in 87/168 reviews. Inconsistency in data limiting recommendations. Recommendations made to improve data collection in future studies.	[56]
2019	Chronic Pain	Gibson	VAS, NRS	No	Three studies reported AE. AEs for the studies reported were primarily skin irritation.	(u)	Recommendations for future studies focused on the comparison groups, timing of pain ratings, data for parameters for reproducibility with adequate intensity and larger sample sizes.	[87]
2018	Chronic Pain	Almeida	VAS	No	No	(+)	TENS and IFC had positive effects on pain level and function	[55]
2018	Fibromyalgia	Honda	VAS	No	No	(+)	Further studies needed	[88]
2017	Fibromyalgia	Johnson	VAS, NRS, Pain relief ≥ 30%	Yes/No	Withdrawal due to increased pain, no reasons given for some of the studies	(u)	Further high-quality studies are needed.	[57]
2017	Fibromyalgia	Salazar	VAS	No	No	(u)	Biases noted with the studies and further research with high quality studies.	[89]
2021	Knee Osteoarthritis	Shi	VAS	No	No	(+)	None	[90]
2017	Knee Osteoarthritis	Li	VAS	No	No	(+)	Further high-quality studies are needed.	[91]
2017	Knee Osteoarthritis	Zhu	VAS in 24 h post-surgery	No	No	(+)	Further studies needed for duration and intensity of TENS.	[92]
2016	Knee Osteoarthritis	Chen	VAS	No	No	(+)	Further RCT with studies with larger sample sizes and longer follow up time frame.	[93]
2016	Knee Osteoarthritis	Cherian	VAS	No	No	(+)	Further long-term studies are needed.	[94]
2015	Knee Osteoarthritis	Zeng	VAS, WOMAC, Present Pain Intensity	No	Reported in 7 of 27 studies with no AEs related to TENS	(−)	None	[95]
2022	Musculoskeletal	Ferrillo	VAS	No	No	(+)	TENS may decrease pain after as single 50 min session and over 25 weeks for 10 weeks	[96]
2021	Musculoskeletal	Koukoulithras	VAS	No	No	(+)	May be helpful, further studies needed.	[60]
2019	Musculoskeletal	Martimbianco	VAS	No	No	(u)	Further high-quality studies are needed.	[59]
2018	Musculoskeletal	Wu	VAS, NRS, McGill Pain Questionnaire, Borg Verbal rating scale (BPS)	No	No	(+), (=)	TENS was found to improve function disability after within 6 weeks of the treatment.	[97]
2016	Musculoskeletal	Page	VAS	No	No	(u)	Recommendations for TENS were uncertain if TENS is more or less effective than glucocorticoid injection with respect to pain, function, global treatment success and active range of motion because of the very low-quality evidence from a single trial.	[98]
2014	Musculoskeletal	Page	VAS, Pain relief > 30%	No	No	(u)	Further studies needed.	[99]
2022	Pelvic Health	Arik	VAS, NRS	No	AE reporting in 3 of 4 studies; No AE reported in these 3 studies	(+)	TENS is safe and well-tolerated and has shown evidence of pain reduction in primary dysmenorrhea	[100]
2020	Pelvic Health	Zimpel	VAS	No	No	(+), (u)	TENS plus analgesia may be of benefit in the first 24 h.	[61]
2016	Pelvic Health	Igwea	VAS, NRS, McGill Pain Questionnaire	No	No	(+)	Additional rigorous high-quality trials are still needed to make conclusive recommendations.	[101]