Tailored transcutaneous electrical nerve stimulation improves dysesthesia in individuals with spinal cord injury: A randomized N-of-1 trial.

Context: Current therapeutic interventions are often ineffective for dysesthesia, including tingling and allodynia, caused by spinal cord injury (SCI). Dysesthesia-matched TENS (DM-TENS) is an innovative approach for dysesthesias that customizes stimulation parameters to align with an individual's specific dysesthesia characteristics.

Objective: We aimed to evaluate the efficacy of DM-TENS for dysesthesia in individuals with SCI.

Design: A randomized, placebo-controlled, aggregated N-of-1 trial was conducted in six individuals with SCI.

Methods: Participants received either DM-TENS as an intervention or sham TENS as a control. Each treatment was administered for 60 min/day over a 7-day period. The outcome measures included the Numeric Rating Scale (NRS) for dysesthesia and Short-Form McGill Pain Questionnaire-2 (SF-MPQ2).

Results: Using a hierarchical Bayesian model, we found that dysesthesia-matched TENS provided clinically meaningful improvements in dysesthesia among individuals with SCI, with a high posterior probability (96-100%) exceeding the minimal clinically meaningful difference (NRS of 2.70) at both the individual and population levels. The mean NRS was 5.79 (95% credible interval [95% CI]: 4.58-7.01) during the placebo period, and 1.12 (95% CI: 0.59-1.66) during the DM-TENS period. In the SF-MPQ-2, the dysesthesia-matched TENS effects showed decisive evidence (BF₁₀ > 1000) for items on tender, pain caused by light touch, tingling or pins and needles, and numbness.

Conclusions: This series of N-of-1 trials comparing dysesthesia-matched TENS with placebo indicated a reduction in dysesthesia in individuals with SCI. Thus, dysesthesia-matched TENS is a promising therapeutic option for managing dysesthesia in this population.Trial registration: UMIN Japan identifier: UMIN000050250..