| Study | Reason for exclusion |
|---|---|
| Al‐Smadi 2003 | Not defined neuropathic pain. |
| Bahtereva 2009 | Not a standard TENS unit application. Unable to contact authors. |
| Bloodworth 2004 | Not randomised/quasi‐randomised trial. |
| Bourke 1994 | Not randomised/quasi‐randomised trial. |
| Casale 1985 | Outcome measure not pain intensity. |
| Cheing 2005 | Pain intensity scoring in response to stimulus evoked pain. Stimulus applied by researcher. |
| Chitsaz 2009 | Outcome measure a VAS composite of pain and sensory complaints. |
| Connolly 2013 | All participants received perceptual TENS. |
| Finsen 1988 | Outcome measure not Pain intensity. |
| Forst 2004 | Outcome measure a VAS composite of pain and sensory symptoms. |
| Franca 2013 | Not defined neuropathic pain. |
| Gossrau 2011 | TENS applied below perceptual level. |
| Heidenreich 1988 | Not clearly randomised trial. |
| Ing 2015 | Not a standard TENS device. |
| Katz 1991 | Outcome measured < 24 hours post‐treatment. |
| Kumar 1997 | Outcome measure not pain intensity. VAS was a composite of pain intensity, paraesthesia and sleep disturbance. Outcome measure not self‐reported. |
| Kumar 1998 | Outcome measure not pain intensity. VAS was a composite of pain intensity, paraesthesia and sleep disturbance. Outcome measure not self‐reported. |
| Lehmkuhl 1978 | Outcome measured < 24 hours post‐treatment. |
| Marques 2014 | Not defined neuropathic pain. |
| Mysliwiec 2012 | Outcome measure not pain intensity. Not defined neuropathic pain participants. |
| Norrbrink 2009 | All participants received TENS. |
| Oosterhof 2008 | No pain intensity follow‐up data. Unable to extract potential neuropathic participant data. |
| Pourmomeny 2009 | Outcome measure not pain intensity. VAS was a composite measure of pain and non‐pain symptoms. |
| Reichstein 2005 | Not all participants had pain as a symptom. Outcome measure encompassed non‐pain symptoms. |
| Sherry 2001 | Not defined neuropathic pain. |
| Stepanovic 2015 | Not defined neuropathic pain. |
| Thorsteinsson 1977 | Outcome measured < 24 hours post‐treatment. |
| Warke 2004 | Not defined neuropathic pain condition in study. |
| Warke 2006 | Not defined neuropathic pain condition in study. |
| Wong 2016 | Not randomised/quasi‐randomised trial. |
| Yameen 2011 | All participants received TENS. |
TENS: transcutaneous electrical nerve stimulation; VAS: visual analogue scale.