Dynamics of clinical and neurophysiological manifestations of generalized anxiety disorder after right median nerve TENS depending on different current modalities.

Objective: To study the efficacy of direct HF TENS and LF TENS of the right median nerve in the treatment of patients with GAD compared to sham TENS. Materials and methods. The efficacy of direct HF TENS and LF TENS of the right median nerve in the treatment of GAD was studied using the 7‑item Generalized Anxiety Disorder Scale (GAD-7). Forty patients completed sham TENS, 40 patients completed HF TENS (50 Hz — 50 μs — sensory response) and 41 patients completed LF TENS (1 Hz — 200 μs — motor response) for 30 days daily. After completing the treatment, half of the patients received weekly maintenance therapy for 6 months. Electroencephalography was performed before and after treatment. Results. A significant reduction in clinical symptoms of GAD as assessed by GAD-7 was observed after HF TENS and LF TENS by an average of 42.4 %, and after imitation TENS only by 13.5 % with the preservation of this effect for 2 months after the end of the treatment course. However, LF TENS had a more pronounced anti-anxiety property compared to HF TENS by 51 %. At the same time, positive dynamics from the EEG side were recorded only after the use of LF TENS, leading to an increase in the spectral power density (SPD) of the alpha rhythm in the occipital areas by 24 % and a decrease in SPD for the beta I rhythm in the temporal and frontal areas by 28 %. The prolonged effect of LF TENS and HF TENS was maintained without negative dynamics with continued TENS treatment weekly throughout the entire six-month observation period. Conclusions: The prolonged anxiolytic effect of direct TENS of the right median nerve has been proven with a more pronounced regression of clinical and neurophysiological manifestations of GAD after LF-TENS compared to HF-TENS. Minimal side effects, low cost, safety and simplicity of TENS procedures are suitable for home treatment.