Effectiveness of high-frequency transcutaneous electrical nerve stimulation at tender points as adjuvant therapy for patients with fibromyalgia. (2013)

Abstract
BACKGROUND:
Fibromyalgia is a chronic pain syndrome associated with sleep disorders, fatigue and psychological symptoms. Combinations therapies, such as electrotherapy and therapeutic exercises have been used in the clinical practice.
AIM:
To assess the efficacy of high-frequency transcutaneous electrical nerve stimulation (TENS) as an adjuvant therapy to aerobic and stretching exercises, for the treatment of fibromyalgia.
DESIGN:
Controlled clinical trial.
SETTING:
Unit of rehabilitation of a public hospital.
POPULATION:
Twenty-eight women aged 52.4±7.5 years, with fibromyalgia.
METHODS:
A visual analogue scale measured pain intensity; tender points pain threshold, by dolorimetry; and quality of life, by the FibromyalgiaImpact Questionnaire. All subjects participated in an eight-week program consisting of aerobic exercises, followed by static stretching of muscle chains. In TENS group, high-frequency (150 Hz) was applied on bilateral tender points of trapezium and supraspinatus.
RESULTS:
TENS group had a greater pain reduction (mean change score=-2.0±2.9 cm) compared to Without TENS group (-0.7±3.7 cm). There was a difference between mean change scores of each group for pain threshold (right trapezium: 0.2±1 kg/cm² in TENS group and -0.2±1.2 kg/cm² in Without TENS group). In the evaluation of clinically important changes, patients receiving TENS had relevant improvement of pain, work performance, fatigue, stiffness, anxiety and depression compared to those not receiving TENS.
CONCLUSION:
It has suggested that high-frequency TENS as an adjuvant therapy is effective in relieving pain, anxiety, fatigue, stiffness, and in improving ability to work of patients with fibromyalgia.
CLINICAL REHABILITATION IMPACT:
High-frequency TENS may be used as a short-term complementary treatment of fibromyalgia.

My Comments:

Pain in the TENS group decreased 30% from 7.7/10 to 5.4 which I would say is good but not great, while the exercise only group pain decreased 13%. Tender point sensitization decreased only in the TENS group, indicating that the TENS is decreasing central sensitization which is a primary finding in fibromyalgia. Ability to work also increased 22% in the TENS group compared to 10% in the exercise only group. Fatigue improved 19% in the TENS group compared to 7% in the exercise only group. Anxiety improved 15% in the TENS group compared to 7% in the exercise only group. Depression improved about equal 18% and 19% in the TENS and exercise only group respectively. I think there is still a lot of optimizing to do with the TENS protocol which in this study was still relatively weak compared to my preferred EMS settings. Overall it provides additional evidence that electric stimulation is beneficial in chronic pain conditions and should be part of the patients physical therapy program.

TENS parameters of this study were:

• Waveform: not given
• Rate: 150 Hz
• Pulse duration: 150 uS
• Treatment duration and frequency: 30 minutes per day, days per week not specified, 8 weeks total
• Pulse amplitude: not specified but increased as tolerated to get a strong but comfortable sensation without muscle contraction
• Duty cycle: continuous
• Electrode placement: 4 electrodes placed over bilateral tender points of trapezium and supraspinatus