Central post-stroke pain (CPSP), is a syndrome which is observed in about 10% of stroke patients and is centralised neuropathic pain that may occur after a cerebrovascular injury. This syndrome is characterized by pain and sensory abnormalities in body parts related to the damaged area of the brain injured by the cerebrovascular lesion [1]. Following the concept of CPSP which was introduced by Edinger in 1891 [2], Dejerine and Roussy in 1906, described thalamic syndrome as the pain of the affected side after thalamic stroke [3]. With the development of brain imaging techniques such as computed tomography and magnetic resonance imaging, CPSP has been reported to be caused by lesions of the spinothalamocortical afferent sensory pathways such as the medulla, pons, midbrain, and cortex [4].

In Western medicine, drugs such as analgesics, antidepressants, and anticonvulsants, are often used to treat CPSP. In severe cases, nerve block, surgery, or deep brain stimulation under local anesthesia may be used [5]. However, no therapies have been proven to be effective at curing CPSP [6]. In traditional oriental medicine, scalp acupuncture therapy is used to treat diseases by stimulating a part of the scalp corresponding to the position of the cerebral cortex area of Western medicine, and is based on function, such as the motor sensory, language, sense of equilibrium, or reproductive area of the cerebral cortex [6].

Although many studies have shown that the scalp acupuncture therapy is particularly effective in treating central nervous system conditions, such as strokes [7-9], in Korea, studies on CPSP are limited [10]. Only a few cases have been reported, and studies on clinical application are lacking.

This case report describes treatment of a patient with CPSP using Scalp Acupuncture and Korean herbal medicine. The condition occurred 6 years after the onset of infarction of the right cerebral cortex. Treatment of the CPSP lasted 4 weeks and was effective.

CPSP is severe in intensity, intractable, and occurs in the opposite side of the body to the damaged area of the brain [11]. The duration is usually a few days to several months, but in some cases, it lasts for years [12]. CPSP is more severe than the pain caused by lesions in other parts of the brain, with greater inconveniences in social activities and daily life. The onset of CPSP is mainly spontaneous. It is frequently altered by internal and external stimuli, such as stress and cold [13]. The intensity of CPSP can be reduced by stability or emotional change [14]. CPSP includes aching pain, burning pain, sore pain, and hyperalgesia, and manifests as recurrent, severe, inveterate, and central pain [11]. In addition, it causes great disruption to the progress of rehabilitation, such as recovery of motor function in stroke patients, and even in the patient’s desire to rehabilitate. It has been reported that CPSP occurs in about 10% of patients and most suffer from severely intense pain [15].

Many medications, such as antidepressants, anticonvulsants, non-steroidal anti-inflammatory drugs, opioids, and steroids have been used to treat central pain, but it has been reported that these medications may sometimes be ineffective [16]. In addition, nerve blocks using local anesthetics or surgical and electrical methods, have been used but the effect has been reported to be temporary or unsatisfactory [17].

In traditional oriental medicine, scalp acupuncture therapy is used to stimulate parts of the scalp corresponding to the position of the cerebral cortex designated by Western medicine and based on function. Acupuncture performed on the scalp has a therapeutic effect in various cerebrovascular diseases/conditions [18].

Introduced in 1950, there are many types of scalp acupuncture (e.g. Fang’s, Tang’s, Zhu’s, Jiao’s, Lin’s) whose acupoints on the scalp relate to function in the cerebral cortex, and this is similar to the theory in anatomical physiology. In 1983, the Chinese Acupuncture Society proposed an “International standardization of scalp irritation sites” and this was agreed at the World Health Organization/Western Pacific Regional Development meeting in Tokyo, in June 1984. It was published at a meeting for the International standardization of bedding acupuncture sites [19] the standardized names were MS1 (sedation), MS10 (analgesic action), MS11 (analgesic action) and MS5 (brain activation).

In this case study, after the cerebral infarction in 2013 the patient experienced tingling pain and numbness in the left hemisphere of his brain. He was hospitalized for 3 months however, his pain was not controlled by narcotic analgesics. He continued to suffer chronic pain for 6 years, resulting in sleep disturbance and insomnia, and a poor quality of life.

To relieve pain, acupuncture was performed once per day for 5 days per week from January 3^rd. The herbal medicine Soonkiwhalwheultang by Qinggangyijian was prescribed for pain and paralytic diseases caused by stroke. At the discretion of the attending physician, physiotherapy was performed.

Since the improvement of symptoms was not evident, scalp acupuncture treatment was performed on the 5^th day of admission. In the process of traditional scalp acupuncture, during the procedure, the needle was rotated 200 times per minute after insertion. After 1-2 minutes of rotation, the needle was retained for 5-10 minutes, and the same method was used to strengthen the stimuli. However, due to the difficulty quantifying the stimuli method the technique was replaced with low-frequency (2 Hz) electrodermal stimulation.

Following scalp electroacupuncture, numbness in the head was alleviated. Gradually, numbness and pain in the upper body also decreased. On the third day of the scalp electroacupuncture, the grip force difference between the 2 hands improved from 3 kg to 2 kg. After 10 sessions of scalp, electroacupuncture, the average grip force difference between the 2 hands was maintained at 0 to 0.5 kg. The patient was satisfied.

From January 18^th, sleep disturbance (which was most distressing to the patient), was resolved. During hospitalization, intermittent symptomatic deterioration due to personal stress and overcast weather conditions was observed, but the average pain remained stable with an NRS score of 6.

Pain in the patient’s head and upper body on the left side were almost relieved during the treatment period of about 1 month. The left- and right-hand grip strength that had improved at 3 weeks was maintained until discharge from hospital. Mild discomfort during walking (due to numbness and tingling pain in the ankle area) remained, but the patient was able to walk unaided. The patient was discharged on February 1^st.

We reported a patient complaining of left side weakness and spontaneous pain after stroke. It was classified as CPSP in view of the onset, lesion site, and clinical symptoms. It appears that stimulation of the acupoints MS1, MS5, MS10, and MS11, located on the scalp, played a major role in improving the patient’s symptoms. Scalp electroacupuncture was applied for about 4 weeks with about 20 sessions, along with other traditional Korean medicine therapies, physiotherapy and Western medicine, to improve the average NRS score from 10 to 5, and muscle strength improved. No systemic side effects occurred. This study is meaningful in that the patient’s CPSP that was not controlled by narcotic analgesics over 6 years, but within 4 weeks of his admission to Chungju Hospital, his level of pain had improved and his sleep disruption resolved, with strength on his left side increasing. Accordingly when a patient’s quality of life improves it restores their motivation for rehabilitation.

This study is limited to 1 patient receiving combined treatments therefore any improvement observed in the patient cannot be attributed to any 1 treatment. In the future, large-scale studies with more patients and an objective evaluation of treatment outcome is necessary so that comparative studies between scalp acupuncture and other treatments can be performed.