With an increasingly aging population, due to demographic changes and modern medicine advancements, the number of patients with Parkinson disease (PD) is equally increasing [1]. According to data from the Korea Health Insurance Review and Assessment Service, the number of patients with PD has increased from 100,716 in 2017 to 116,504 in 2021, a marked increase of approximately 16% over five years [1], with an increased prevalence with age.

As PD progresses, various bodily functions, including walking ability and daily living performance, gradually deteriorate due to a reduction in muscle strength and balance control ability. Consequently, physical dependence increases and independence is lost [2], resulting in reduced bodily function, further loss of independence, and increased risk of falls [3]. Experiencing a fall causes fear of falling, limited physical activity, and poor daily living standards and can create a vicious cycle of physical function deterioration, disconnected social relationships, and depression [4].

A previous study reported that the presence of kyphosis and flexed posture, common traits of PD, can result in musculoskeletal pain, particularly chronic low back pain (LBP), by overburdening the paraspinal muscles [5]. In a study on pain in patients with PD, 83% of all patients experienced pain, which was generally classified as neuropathic, central nervous system, dystonia-related, or musculoskeletal pain [6,7].

In addition, chronic LBP can lead to decreased gait balance (motor symptoms), exacerbated depression, anxiety about the risk of falls (non-motor symptoms), and a decline in quality of life [8]. Unfortunately, these non-motor symptoms are often dismissed as mere byproducts of aging or overshadowed by the more prominent symptoms of the disease, such as stiffness and tremor, and consequently receive inadequate attention and treatment [9,10].

Heat treatment is a widely-used approach for the management of chronic back pain [11]. Lumbar muscle myofascial release technique (LMTT) is a form of heat treatment with acupressure that reduces pain in damaged tissues, increases blood flow, and relaxes muscles [12]. This localized heat application can relax the muscle by reducing the muscle spindle stimulation threshold and gamma nerve fiber firing rate [13]. Additionally, the LMTT focuses on the fascia that causes pain in the human body [14]. Fascia acts as a lubricant to allow smooth and fluid movement of the body’s tissues [14]. Pain can be alleviated by improving the arrangement of the fascia and elongating shortened soft tissue [15].

The purpose of this study was to investigate whether LMTT, when applied to patients with chronic pain, is effective in improving overall disease severity of chronic pain, motor symptoms including physical functions, and non-motor symptoms such as depression and pain.

1. Study population

An experimental study was conducted with 19 patients who visited a medical institution for chronic pain and were receiving drug treatment. The participants were approached directly after outpatient treatment between April 1 and April 30, 2022, during which the purpose of the study was explained.

The inclusion criteria for this study were as follows: (1) chronic back pain diagnosed by a specialist; (2) patients with the cognitive ability to understand the purpose of this study and follow the researcher’s movement instructions; and (3) those who were capable of carrying out sufficient daily activities to allow research conduction and who show stages 1 to 2 on the Hoehn and Yahr Scale (H&Y Scale). The exclusion criteria were as follows: (1) previous orthopedic or neurosurgery; (2) cardiovascular disease; (3) complaints of headache or dizziness; and (4) participation in regular exercise programs.

Chronic back pain was defined as pain that has persisted for more than 8 weeks and has a visual analog scale (VAS) score of 3 or more localized to the lower back area as musculoskeletal pain. Chronic back pain was evaluated by a specialist such as a rehabilitation medicine doctor or physical therapist.

Patients were registered after obtaining their consent. Of the 17 patients, 12 completed 10 sessions of thermal therapy with an acupressure device. Treatment was discontinued for five patients due to personal circumstances after completing the consent form.

This study was approved by the Institutional Review Board of Kyungpook National University Hospital (IRB No. 2022-01-023-001).

2. Study intervention

The erector spinae is situated along the central core of the spine and comprise the longissimus, spinalis, and iliocostalis muscles. These muscles extend upwards to the chest and head, and downwards to the waist and pelvis.

In pursuit of our objective, we developed an LMTT. The device (3H Massage Bed, Daegu, South Korea) used in this study was designed to align with the location of the paraspinal muscles, facilitating muscle stretching and relaxation. This device used a treatment mode called ‘back intensive acupressure’. This mode operates for 20 minutes per 1 session, and treatment apply at an average intensity of 21.6 kg/f.

It is anticipated to serve as an effective non-pharmacological treatment alternative. The device provided heat to the lower back area as well as acupressure, upward and downward, to the paraspinal muscles. To achieve this, a myofascial release technique was used, in which limited pressure was applied to the barrier of the fascia tissue. The acupressure rod was designed and constructed to align with the position of the erector spinae fascia.

3. The mechanical system of the treatment device

A bogie, also known as a wheel truck, typically refers to a wheeled pedestal, used to transport and move goods. In this study, as shown in Fig. 1, a bogie with a tripod structure was designed to move along a rail using the power of a motor to convert horizontal energy into vertical energy. As the bogie moved, ceramic acupressure rods positioned at specific heights were sequentially pushed upward, facilitating a repetitive horizontal motion as many times as necessary by applying a timing belt to enable reciprocating motion. Additionally, as shown in Fig. 2, an X-shaped height adjustment module was incorporated into the bogie, allowing the acupressure bar to move up to 100 mm in both left and right directions, and increase its elevation by 140 mm (Fig. 3). To enhance the therapeutic effect, the device uses aluminum, which has high thermal conductivity, to simultaneously apply heat, reaching temperatures up to 70°C, and acupressure. A heating wire was attached to the device to facilitate this process. The device was designed and manufactured to provide acupressure to the operational portion, which was integrated with the bogie method. As shown in Fig. 4, the acupressure rods were arranged at a distance of 40.0 mm from the core to the center of the first acupressure rod.

Figure 1. System configuration image.

Figure 2. Structure of the operating part.

Figure 3. X-ray showed spinal segmentation motion. (A) Lumbar spine in treatment. (B) Thoracic spine in treatment.

Figure 4. Therapeutic thermal acupressure massage device.

4. Study design

The LMTT was administered ten times to the patients with chronic pain who participated in the study. Using the same measurement tool and evaluator, the participants were assessed for pain, gait, fear of falling, and various parameters determining their quality of life due to pain. The evaluation period was divided as follows: (1) pre-intervention evaluation conducted immediately after obtaining written consent to participate in the study and again immediately before commencing the first session of thermal therapy and acupressure device, which took place 2 weeks after written consent was obtained; (2) interim evaluation immediately after the 5th session of thermal therapy and acupressure device; (3) post-intervention evaluation immediately after the 10th session of thermal therapy and acupressure device; and (4) follow-up evaluation 2 weeks after the completion of thermal therapy and acupressure device sessions. During the study period, the participants did not undergo any other pain-related procedures or use medications.

5. Variables

1) Demographic characteristics

Gender, age, pain duration (months), and current rehabilitation treatment data were collected for all participants. Patients were classified as male or female, and current rehabilitation treatment was classified as “yes or no”.

2) Motor symptoms on pre-post metrics: Timed Up and Go (TUG), 10 m gait time, 6 min gait speed, Berg Balance Scale (BBS), and Functional Ambulatory Category (FAC)

In the TUG, participants stood up from a seated position on a chair, walked 3 m, and returned to the seated position. The time taken to walk back to the chair and return to the seated position was measured [16]. In the 10 m gait test, the participants walked 13 m in a straight line on a flat surface at a pace that felt comfortable and safe, but as fast as possible [17]. In the 6 min gait evaluation, the maximum walking distance completed in 6 min was measured. For this study, a 100 m round track was drawn and marked at 1 m intervals to accurately measure the completed distances [18]. The BBS was used to evaluate functional movements. The patients’ time to maintain balance in both sitting and standing positions, their need for a support object while sitting, their performance with eyes closed in the standing position, their capability to stand on one leg, their capability to lift an object, and their ability to perform one rotation were scored. Each item was scored from 0-4, with a total score of 56 points. A higher score indicated a higher level of static and dynamic balance [19]. The FAC was used to test walking ability and comprises scores from 0-5. A higher score indicated that the participant was able to walk independently [20].

3) Non-motor symptoms: Pain Visual Analog Scale (VAS), fear of falling, Oswestry Disability Index (ODI), and Geriatric Depression Scale Short Form (GDSSF)

The VAS comprises a 10-20 cm line , either vertical or horizontal, with “no pain,” and “extremely sever pain” written at either end [21,22]. The participant indicates their perceived pain on the line and the pain is scored from 0 to 10 (left to right or top to bottom). A visual similarity scale was also used in this study.

The fear of falling questionnaire was developed to screen participants’ fear of falling, considering the need for a more valid and reliable tool [23,24]. The questionnaire comprises questions about the fear of falling when performing seven daily activities: getting dressed or undressed, taking a bath or shower, getting in or out of a chair, going up or down stairs, reaching for something above your head or on the ground, walking up or down a slope, and going out to a social event. The responses to the questions were rated on a 4-point Likert scale, with higher scores indicating a greater fear of falling.

The ODI is a valid and reliable evaluation tool used to measure both pain and physical ability. It offers a user-friendly approach compared to other tools, making it an appropriate tool for evaluating the level of disability in patients who are experiencing pain [25]. The disability questionnaire comprises 10 items, with each item assigned a score of 0-5 points (six-point ranking scale). After adding the responses for each item, dividing the answer by the total score (50 points) and multiplying it by 100, the total score was displayed as a percentage (%). Clinically, a higher score indicates a greater degree of dysfunction [26,27].

The GDSSF was developed by Sheikh and Yesavage in 1986 as a tool for evaluating symptoms of depression in the elderly [28]. In this study, we used the Korean version of the Depression-Simplified Scale for the Elderly, which was modified for the elderly Korean population. It comprises a total of 15 items, with a maximum possible score of 15 points, where a score of < 6 is considered normal, and a score of > 6 indicates the presence of depressive symptoms [29].

6. Data analysis

Statistical analysis was conducted using R version 4.2.0 software, an open-source analysis software. The primary outcome variables, depending on the intervention, included the scores for VAS, fear of falling, ODI, GDSSF, and various movement symptom-related variables (TUG, 10 m gait speed, 6 min walk test, BBS, and FAC).

The significance level for rejecting the null hypothesis was set at P < 0.05. For the variables measured at five different time points, the Bonferroni test was performed as a ‘post hoc’ analysis after the Kruskal-Wallis test, which is a nonparametric ANOVA test. The Wilcoxon signed-rank test, a nonparametric paired t-test, was performed for the variables measured before and after the intervention.

1. Patient demographics

The demographic characteristics of the 12 study participants were as follows: 8 men (66.7%) and 4 women (33.3%); average age, 67.58 ± 7.10 years old (range 51-81); mean duration of pain, 122.67 ± 66.68 months (range 30-240); 4 participants (33.3%) were receiving rehabilitation treatment at the time, and 8 participants (66.7%) had not receive any rehabilitation (Table 1).

Table 1 . Demographic characteristics of participants (N = 12).

Characteristics	n (%) or M ± SD	P
Gender		.002
Male	8 (66.7)
Female	4 (33.3)
Age (range: 51-81)	67.58 ± 7.10	-
Duration of pain (month) (range: 30-240)	122.67 ± 66.68	-
Current rehabilitation treatment		.025
Yes	4 (66.7)
No	8 (33.3)

N: number of participants; M ± SD: mean ± standard deviation..

2. Pain and functional gait-related characteristics

Table 2 shows the pain and functional gait characteristics of the 12 participants, as well as the sex, age, and area of pain occurrence (lower back). The table also shows the severity of low back pain, gait function, TUG time, time taken for 10 m gait (s), and distance traveled for 6 min gait (m) before the intervention.

Table 2 . Pain and functional gait-related characteristics by individual participants (N = 12).

Participants	Sex/age	Pain			Functional gait
		Region	Severity		Gait function	TUG (sec)	10 m gait (sec)	6 min gait (m)
No. 1	M/67	Low back	3		Independent gait	19	13	430
No. 2	M/64	Low back	7		Independent gait under supervision	16	17	340
No. 3	M/70	Low back	8		Independent gait under supervision	19	17	180
No. 4	F/69	Low back	9		Independent gait with 2-mono cane	30	18	150
No. 5	M/51	Low back	7		Independent gait under supervision	10	8	400
No. 6	M/75	Low back	8		Independent gait under supervision	18	11	320
No. 7	M/74	Low back	6		Independent gait under supervision	16	12	365
No. 8	M/64	Low back	7		Independent gait under supervision	12	8	340
No. 9	F/81	Low back	7		Independent gait with 1-mono cane	15	11	250
No. 10	F/67	Low back	6		Independent gait with 1-mono cane	15	12	320
No. 11	F/65	Low back	8		Independent gait under supervision	25	18	280
No. 12	M/64	Low back	6		Independent gait	13	10	420

TUG: Timed Up and Go..

3. Change in VAS, fear of falling, ODI, and GDSSF mean scores after intervention

The VAS mean score was 6.54 in the pre-intervention evaluation, 5.54 immediately prior to commencing therapy, 4.46 after the 5th session, 3.00 after the 10th session, and 4.00 at the 2 week follow-up evaluation, indicating a significant improvement over the time period (P < .001). As a result of the post-hoc test, the VAS mean score was the same at the time of pre-intervention evaluation and immediately before the sessions, but the visual similarity scale score decreased immediately after the 5th treatment and the 10th treatment. The decreased value was maintained at the 2 week follow-up. The lower the mean VAS score, the better the patient’s condition was. There were no significant differences in the results of the other measurement items (fear of falling, ODI, and GDSSF) (Table 3, Fig. 5).

Table 3 . Change in VAS, fear of falling, ODI, and GDSSF mean scores after intervention.

Variables	Before 1a	Before 2b	Intervention 1c	Intervention 2d	After follow-upe	F	P	Bonferroni
VAS	6.54 ± 1.81	5.54 ± 1.45	4.46 ± 1.61	3.00 ± 1.16	4.00 ± 1.16	4.71 ± 1.877	< .001	a, b > c, d, e
Fear of falling	20.08 ± 6.38	19.08 ± 6.09	18.00 ± 5.86	16.92 ± 6.16	18.54 ± 6.11	18.52 ± 6.021	.749	-
ODI	24.77 ± 8.94	23.85 ± 8.46	22.62 ± 8.23	21.08 ± 7.64	22.54 ± 8.35	22.97 ± 8.17	.829	-
GDSSF	2.77 ± 2.24	2.85 ± 2.44	2.69 ± 2.53	2.15 ± 2.23	1.92 ± 2.14	2.48 ± 2.278	.801	-

VAS: Visual Analog Scale; ODI: Oswestry Disability Index; GDSSF: Geriatric Depression Scale Short Form..

Figure 5. Change of VAS: Post-hoc (Bonferroni test) Before 1, Before 2 < Intervention 1, Intervention 2, After follow-up (P < .001). The decreased value was maintained even after 2 weeks of follow-up. The lower the VAS score, the better the condition of patients with chronic pain. There were no significant differences in the results of the analysis of the other five measurement items.

4. Change in TUG, 10 m gait speed, 6-min walk test, BBS, and FAC mean scores after intervention

The TUG exhibited a significant reduction from 17.33 sec before the intervention to 13.50 sec after the intervention (P < .001). In the case of 10 m gait speed, a significant reduction was observed from 12.92 sec to 10.00 sec (P = .001). In the 6 min walk test, a significant increase was observed from 316.25 m to 345.00 m (P = .001). The BBS score significantly increased from 41.58 points to 44.42 points (P = .001). The FAC did not differ significantly between the pre- and post-hoc tests (P = .339). Analysis of pre- and post-measurement items revealed that the condition of patients with chronic pain improved after the intervention (Table 4).

Table 4 . Change in TUG, 10 m gait speed, 6-minutes’ walk test, BBS, and FAC mean scores after intervention.

Variables	Pre-test	Post test	Pre-Post	t	P
TUG	17.33 ± 5.56	13.50 ± 3.97	3.83	5.202	< .001
10 m gait speed	12.92 ± 3.70	10.00 ± 2.56	2.92	4.791	.001
6 min walk test	316.25 ± 88.50	345.00 ± 74.74	–28.75	–4.472	.001
BBS	41.58 ± 10.59	44.42 ± 8.75	–2.83	–4.444	.001
FAC	3.33 ± 1.56	3.42 ± 1.51	–.083	1.000	.339

TUG: Timed Up and Go; BBS: Berg Balance Scale; FAC: Functional Ambulation Classification..

In this study, we investigated the pain reduction effect through the application of LMTT in PD with chronic back pain. This study confirmed improvements in pain up to the 5th round of treatment compared to those before the start of thermal acupressure stimulation bed treatment. Compared with the pre-intervention evaluation, the reduction in pain in the post-intervention evaluation was confirmed after 10 sessions. The significantly reduced pain intensity persisted until the 2-week follow-up evaluation after completion of the LMTT sessions.

The patient’s pain levels in this study decreased significantly post-intervention compared to that observed pre-intervention (T1: 7.00 ± 1.58, T4: 3.38 ± 1.56), and the pain score decreased at the follow-up evaluation (T5: 4.38 ± 1.56). In this study, LMTT was performed on the erector spinae muscle and a significant decrease in the VAS score was confirmed during the treatment sessions. In a previous study [30], various forms of heat therapy applied to the body were shown to activate heat receptors and transmit signals that block pain signal processing in the spinal cord. In addition, increasing tissue temperature through the application of thermal devices can expand the blood vessels involved in metabolism and increase the speed of the pain-healing process. In addition, acupressure therapy, when combined with thermal effects, can stimulate proprioceptors that send signals to the spinal cord and brain, thereby blocking pain transmission throughout the body [31]. Therapeutic stimulation for symptom relief in patients with PD has reported beneficial effects and is among the most commonly used complementary therapies [32,33]. Therefore, when used in conjunction with thermal therapy and acupressure, LMTT can provide significant pain relief, is easy to use, and is more cost-effective than receiving an acupressure device from a therapist. Additionally, it allows users to perform regular LMTT without requiring special skills or experience.

Franchignoni et al. [34] reported that patients with neurological impairments, such as PD, had impaired movement and functional abilities, and an increased fear of falls. Adkin et al. [35] reported that patients with PD exhibited claudication and decreased confidence in their balance compared with patients without PD. In a study examining the correlation between lower back pain and falls, pain in any part of the body increased the fear of pain, and previous experience of falling due to pain increased the fear of falling [36]. Increased physical disabilities due to lower back pain increases the fear of falling due to the fear of performing normal functions. In this study, after 10 sessions of LMTT, a significant reduction in pain and maintenance thereof, was observed (P < .001), but no reduction in fear of falling was evident (P = .749). However, there was a comparative improvement in the overall functional evaluation results, TUG, 10 m gait speed, 6 min walk test, and BBS. However, to allow accurate evaluations, it should be considered that people who had reduced physical activity due to existing pain or functional decline had to perform physical activity with the LMTT almost every day for 2 weeks for the study. The increased activity level may also influence the overall functional improvement [37]. Therefore, it is unclear whether the observed improvement in function was due to physical activity or an actual improvement in PD, making it challenging to determine the cause of the observed improvement.

This study has several limitations. First, it was performed with outpatients at a university hospital using convenience sampling, and since it is a preliminary study with a small number of subjects, which may limit the generalizability of the results. However, this limitation was supplemented statistically. Second, because of the small number of patients with PD, they could not be grouped according to the time of PD diagnosis and degree of detailed PD symptoms. The lack of statistical studies on the factors affecting symptom improvement after intervention is a limitation. Therefore, we plan to conduct additional studies targeting several patients with PD in the future.

Nevertheless, the results of this study confirmed the effectiveness of the LMTT for pain improvement and fear of falling, which are neglected non-motor symptoms, compared to motor symptoms in patients with PD. Notably, this study enabled the collection of preliminary data for an experimental study that can assess various non-motor symptoms. The results of this study may lead to the application of LMTT in other patients in the future, which will require the development of a specific and long-term intervention program to manage non-motor symptoms.

In the present study, through the application of LMTT, a significant reduction in pain was observed in patients with PD who complained of chronic back pain. This confirmed that the application of the LMTT was effective in improving pain and fear of falling, which are neglected symptoms compared to the more prominent symptoms of PD. Through this study, it is believed that by increasing the number of participants and applying LMTT in the future, this be presented as an effective treatment method to alleviate non-motor symptoms, including chronic back pain in patients with PD.

This paper is the result of research conducted with support from the Kmedihub project.

No potential conflict of interest relevant to this article was reported.