The effect of two different types of electric current on experimental pain threshold in healthy individuals: A double blind, randomized controlled trial

19 CMJ Original Research March 2020, Volume: 42, Number: 1 Cumhuriyet Tıp Dergisi (Cumhuriyet Medical Journal) 19-27 http://dx.doi.org/10.7197/cmj.vi.676491 The effect of two different types of electric current on experimental pain threshold in healthy individuals: A double blind, randomized controlled trial Sağlıklı bireylerde iki farklı elektrik akımı tipinin deneysel ağrı eşiği üzerindeki etkisi: Çift kör randomize kontrollü çalışma Ayşe Numanoğlu Akbaş 1, Sinem Suner Keklik 1, Hatice Yakut2, Ömer Osman Pala1 1 Cumhuriyet University, Health Sciences Faculty, Physical Therapy and Rehabilitation Department, Sivas, Turkey. SüleymanDemirel University, Health Sciences Faculty, Physical Therapy and Rehabilitation Department, Isparta, Turkey Corresponding author: Ayşe Numanoğlu Akbaş, MD, Cumhuriyet University, Health Sciences Faculty, Physical Therapy and Rehabilitation Department, Sivas, Turkey. E-mail: Received/Accepted: January 17, 2020 / May 11, 2020 Conflict of interest: There is not a conflict of interest. 2 SUMMARY Objective: Physiotherapists often resort to electrophysical agents for pain management. The aim of this study is to determine the effect of acupuncture-like Transcutaneous Electrical Nerve Stimulation (TENS) and Neuromuscular Electrical Stimulation (NMES) on experimental pressure pain threshold (PPT) in healthy individuals. Method: Sixty one healthy participants (44 females, 17 males) aged 18-21 years were included in the study.The participants were divided into acupuncture-like TENS and NMES groups. The application was performed for 20 minutes from the right upper limb. The PPT changes of the participants were evaluated from the thenar part of both hands with an algometer before the current application, immediately after and 60 minutes after. Results: There was no difference in the PPT levels of the right and left extremities of the participants in both groups before the application (p>0.05). In both groups and intergroup comparisons, there was no difference in PPT levels measured from the right and left extremities of participants before the current application, immediately after and 60 minutes after the current application (p>0.05). Conclusions: In this study, it was concluded that acupuncture-like TENS and NMES had no effect on experimental PPT and therefore, the clinical use of currents should be questioned. Keywords: Electric stimulation therapy, pain, physical therapists, pressure. Ayşe Numanoğlu Akbaş Sinem Suner Keklik Hatice Yakut Ömer Osman Pala ORCID IDs of the authors: A.N.A. 0000-0001-9296-8972 S.S.K. 0000-0002-9506-3172 H.Y. 0000-0002-0033-0144 Ö.O.P. 0000-0002-1826-5723 ÖZET Amaç: Fizyoterapistler genellikle ağrı yönetimi için elektrofiziksel ajanlara başvurmaktadırlar. Bu çalışmanın amacı sağlıklı bireylerde akapunktur benzeri Transkutanöz Elektriksel Sinir Stimulasyonu (TENS) ve Nöromusküler Elektrik Stimulasyonunun (NMES) deneysel basınç ağrı eşiği (BAE) üzerindeki etkinliğinin belirlenmesidir. 20 Yöntem: Çalışmaya 18-21 yaş arası 61 sağlıklı birey (44 kadın, 17 erkek) dâhil edildi. Katılımcılar akapunktur benzeri TENS ve NMES grubuna ayrıldı. Uygulama sağ üst ekstremiteden 20 dakika süreyle yapıldı. Katılımcıların BAE değişimleri akım uygulamasından önce, hemen sonra ve 60 dakika sonra algometre ile her iki elin tenar bölgesinden değerlendirildi. Bulgular: Her iki grupta yer alan bireylerin sağ ve sol ekstremitelerinin uygulama öncesi BAE düzeyleri arasında fark yoktu (p>0.05). Her iki grupta da ve gruplar arası karşılaştırmalarda uygulama öncesi, uygulamadan hemen sonra ve 60 dakika sonra sağ ve sol ekstremiteden ölçülen BAE düzeylerinde fark yoktu (p>0.05). Sonuç: Bu çalışmada Akapunktur benzeri TENS ve NMES’in deneysel BAE üzerinde etkisi olmadığı bu nedenle akımların klinikteki kullanımlarının sorgulanması gerektiği sonucuna varılmıştır. Anahtar sözcükler: Elektrik stimulasyon terapisi, ağrı, fizyoterapist, basınç INTRODUCTION Coping with pain is one of the main goals of physiotherapy and rehabilitation applications 1. Physiotherapists often apply on electrophysical agents for pain management 2. The main purpose of physical therapy applications in pain management is to reduce pain severity, to increase pain threshold and tolerance by using different mechanisms 3. It is seen that the factors such as preferences of physiotherapist and patient, available devices, contraindications of the patient are taken into consideration when choosing the types of electrical current in clinical applications for pain management 4. The electrical current most commonly used by physiotherapists to achieve the analgesic effect is Transcutaneous Electrical Nerve Stimulation (TENS) 5. TENS is a simple and noninvasive modality used to reduce acute and chronic pain; is often preferred because it is cheap, safe, easy to use and has few side effects and drug interactions 3, 6. It has been hypothesized that different parameters will activate different inhibition mechanisms in TENS treatment and in parallel with that there may be changes in the start and duration of analgesia 68 . Theoretically, it is assumed that TENS with high frequency-low intensity shows effect by the segmental pain inhibition process (gate control theory) and TENS with low frequency-high intensity shows effect by releasing of endogenous opioids (suprasegmental effect) 9. However, studies on this subject have not reached a definitive conclusion yet; many studies have indicated that there was no difference in terms of the effects of different TENS types. Despite this, there are also studies reporting that there are differences in terms of the effects of TENS applications with highfrequency or low-frequency 10-14. The most effective combination of stimulation parameters in TENS treatment is still unknown 15. Neuromuscular Electrical Stimulation (NMES) is an electrostimulation technique used to achieve contraction in muscle through excitation of motor nerves 8. The main uses of NMES are strengthening of muscles, prevention of muscle atrophy and degeneration, preservation or increase of joint range of motion 7, 16. However, the literature shows that NMES is also used for pain control in various pathologies 17, 18. Although there is a wide range of use in the clinic, it is reported that a stimulation frequency of 30-100 Hz and a phase time of 0.3 ms are effective in many applications 8, 16. There are several studies in the literature examining the effects of different types of TENS on experimental pain 19-21. There has been no study examining the effects of NMES on experimental pressure pain threshold.The aim of this study is to determine and compare the effectiveness of acupuncture-like TENS and NMES on experimental pressure pain threshold in healthy individuals. MATERIAL AND METHODS The participants of this study were selected on a voluntary basis from healthy individuals aged 1845 who had not received any diagnosis. Male and female individuals without any pathology causing (...truncated)