Low frequency sound stimulation greatly improved the outcome of a refractory postherpetic neuralgia patient with mood and sleep disorder: a case report.

Postherpetic neuralgia (PHN) is a common and severe chronic complication of the herpes zoster (HZ) virus (shingles) involving prolonged pain which may last from weeks to years. Primary treatment involves oral therapies, although few patients experience a pain reduction of greater than 50%. Due to limited effective treatments, symptoms and comorbidities, including physical disability and emotional distress, are recurrent, and interfere with daily activities and sleep. A 34-year-old male had experienced refractory PHN on the right 3 to 5 thoracic dermatomes for about 3.5 years, accompanied with mood and sleep disorder. During this time, several treatments had been attempted, including systemic tricyclic antidepressants, opioid analgesics, anticonvulsants, topical lidocaine, epidural block, and spinal cord stimulation (SCS); however, their outcomes had been unsatisfactory. Low frequency sound stimulation (LFSS) was found effective in reducing the pain, and improving the state of both mood and the sleep. At the time of this report, the patient had been using this treatment for more than 240 days, his quality of life had improved significantly, and no side effects had been observed. LFSS is component of musical therapy, which categorized under complementary and alternative medicine (CAM). It uses audible sound (40-120 Hz) to produce a physical effect through the transducer when applied directly to the body, which can affect pain perception via mood and sleep improvement, activating an anti-pain effect in the brain. This case provides a rationale to study LFSS in patients with refractory neuropathic pain.