Evaluation of transcutaneous electrical nerve stimulation as an adjunct therapy in trigeminal neuralgia - a randomized double-blind placebo-controlled clinical study

Abstract

Background Trigeminal neuralgia (TN) is a severe form of pain that affects the daily activities of a patient. Transcutaneous electrical nerve stimulation (TENS) therapy is an emerging option for the treatment of acute and chronic pain. The aim of this study was to evaluate the effect of TENS therapy as an adjunct to drug therapy for the treatment of TN. Methods A total of 52 patients diagnosed with TN according to the International Classification of Headache Disorders (version 3) were included. Each patient was randomized to either the TENS or placebo TENS groups. Intervention was given in continuous mode and 100-Hz frequency for 20 mins biweekly for 6 weeks. Parameters were measured at baseline, TENS completion and 3 months, 6 months, and 1 year of follow up. The parameters observed were mean carbamazepine dose, mean visual analog scale (VAS) score, mean present pain intensity (PPI) score, and functional outcome. Non-parametric analyses, one-way ANOVA and the Kruskal-Wallis test were applied for intragroup comparisons, while the Mann-Whitney U test and independent t-test were used for intergroup comparisons of variables. The chi-square test was applied to analyze categorical data. Results Compared to the placebo TENS group, the mean dose of carbamazepine in the TENS group was significantly reduced at TENS completion, as well as at 6 months and 1 year follow up. Changes in mean VAS score, mean PPI score, and functional outcome did not show significant differences between the groups (P>0.05). Conclusion TENS therapy does not lead to any changes in pain levels but it may reduce the mean dose of carbamazepine when used as an adjunct treatment in patients with TN.

Clinical and cognitive effects of external trigeminal nerve stimulation (eTNS) in neurological and psychiatric disorders: a systematic review and meta-analysis

“…of migraine days nt Jiang et al [ 42 ] 165 31 ± 11 Open-label, parallel, RCT 60 Hz eTNS + FLZ vs FLZ 91 20 Day 16 No. of migraine days, % responder rate, migraine pain intensity; medication intake nt Trigeminal Neuralgia Bisla et al [ 71 ] 52 56 ± nr Double-blind, parallel, RCT 100 Hz eTNS + CBZ vs sham eTNS + CBZ 12 20 Day nr Pain intensity, pain impact on everyday functioning nt Yameen et al [ 72 ] 31 50 ± 11 Open-label, parallel, non-RCT Constant v Theta-Burst 250 Hz eTNS nr 30 Day nr Pain intensity nt ADHD-RS Attention-Deficit/Hyperactivity Disorder Rating Scale, ANT Attention Network Task, BAI Beck Anxiety Inventory, BDI Beck Depression Inventory, CBZ Carbamazepine, CDI Children’s Depression Inventory, CDRS-Revised Children’s Depression Rating Scale, CGI Conners Global Index, CGI-I Conners Global Index Investigator-Rated, CGI-S Conners Global Index Self-Rated, CSHQ Children’s Sleep Habits Questionnaire, C-SSRS Columbia Suicide Severity Rating Scales, DHI Dizziness Handicap Inventory, ELDQOL Epilepsy and Learning Disabilities Quality of Life Scale, ESS Epworth Sleepiness Scale, eTNS external trigeminal nerve stimulation, FLZ Flurazine, GCI-I Global Clinical Impression-Investigator Rated, HARS Hamilton Anxiety Rating Scale, HDRS Hamilton Depression Rating Scale, HIT Headache Impact Test, HRSD Hamilton Rating Scale for Depression, Hz Frequency, IES-R Impact of Event Scale — Revised, ISI Insomnia Severity Index, LSSS Liverpool Seizure Severity Scale, MASC Multidimensional Anxiety Scale for Children, MOCA Montreal Cognitive Assessment, NDP Nimodipine, NM Nimesulide, nr not reported, nt not tested, PCL-C Post-Traumatic Stress Disorder (PTSD) Check List Scale, PSS Pittsburgh Sleep Scale, PSQI Pittsburgh sleep quality index, RBZ Rizatriptan, RCT randomized controlled trial, SDMST Sternberg delayed match to sample task, SF-36 Short Form Health Survey, SWMT Spat...…”

“…The mean dose of carbamazepine prescribed to participants was significantly reduced immediately, 6-weeks, 12-weeks, but not 3-months, after real stimulation compared to sham, while pain intensity and its effect on everyday functioning remained unchanged. No group-by-time interaction was conducted [ 71 ]. One parallel-arm, unblinded head-to-head trial ( N = 31 adults with trigeminal neuralgia) reported improvement in pain intensity with constant or theta-burst eTNS, for 3 weeks, but without statistical analyses [ 72 ].…”

“…Patients not included in the analysis were equally distributed among the three groups. Trigeminal Neuralgia Bisla et al [ 71 ] Not reported Yameen et al [ 72 ] Not reported …”

“…In epilepsy, daily eTNS use of up to one-year can significantly improve seizure frequency, dimensional measures of depression symptoms, and quality of life, but longer-term effects have not been studied, and most trials are unblinded or single-arm trials and therefore vulnerable to outcome assessor bias. In trigeminal neuralgia, there is evidence of reduced medication intake and inconsistent evidence of reduced pain intensity, but this is based on only two trials that failed to test or report a significant group-by-time interaction [ 71 , 72 ]. Therefore, while on balance our meta-analytic findings favor the use of eTNS combined with anti-migraine medication in migraine, there is encouraging albeit emerging evidence of wider applications in ADHD and epilepsy particularly, that need replication and further exploration with well-blinded RCTs with longer-term follow-ups.…”

“…Bisla et al [71] Not reported Yameen et al [72] Not reported of depressive symptoms. In another study, quality of life remained unchanged in one study in participants with MDD [55].…”