Segmental Laser Acupuncture for Constipation and Sleep in Patients With Parkinson's Disease

Segmental Laser Acupuncture at T10-L2 and S2-S4 for Gut-Brain Axis Modulation in Parkinson's Disease: A Randomized Double-Blind Clinical Trial on Constipation and Sleep Outcomes

Parkinson's disease (PD) is characterized not only by motor symptoms but also by common and clinically significant non-motor symptoms, including constipation and sleep disturbances, which can substantially impair quality of life. The concept of the "gut-brain axis" describes bidirectional communication among the central nervous system, autonomic nervous system, enteric nervous system, and gut microbiota. Increasing evidence from animal models suggests that the gut-brain axis may play an important role in the pathophysiology and progression of PD.

Given the central role of autonomic nervous system regulation in the gut-brain axis, this study will use laser acupuncture as a safe, non-invasive form of photobiomodulation (PBM) with potential neuromodulatory effects. Based on the concept of segmental neuromodulation, laser stimulation will be applied to the thoracolumbar paraspinal regions (T10-L2) and sacral segments (S2-S4, corresponding to the Baliao points) to modulate sympathetic activity arising from T10-L2 and pelvic parasympathetic activity arising from S2-S4. This approach is intended to promote intestinal motility and defecation reflexes. Meanwhile, by modulating autonomic balance and stabilizing stress-sleep rhythms, as assessed by salivary biomarkers including salivary cortisol and salivary alpha-amylase (sAA), the intervention is expected to improve sleep quality in patients with PD.

This study is designed as a randomized, double-blind, sham-controlled clinical trial. Participants with PD who experience constipation will be recruited and undergo an 8-week intervention. The primary outcomes will assess changes in constipation symptoms using the Bristol Stool Form Scale (BSFS) and the Constipation Scoring System (CSS; Agachan Score). Secondary outcomes will assess sleep quality using the Parkinson's Disease Sleep Scale-2 (PDSS-2) and the REM Sleep Behavior Disorder Screening Questionnaire (RBDSQ). Objective salivary biomarkers, including salivary cortisol and sAA, will also be measured to investigate changes in autonomic function and their associations with improvements in clinical symptoms.

This study is expected to provide preliminary evidence regarding the potential role of segmental laser acupuncture in modulating the gut-brain axis and improving non-motor symptoms in patients with PD, thereby providing a basis for future larger-scale studies and the development of clinical care strategies.

Inclusion Criteria:

• Diagnosis of Parkinson's disease by a neurologist according to the Movement Disorder Society (MDS) clinical diagnostic criteria.
• Coexisting chronic constipation meeting the Rome IV diagnostic criteria. Age ≥ 50 years.
• Stable dosage of anti-Parkinson's medications for at least 4 weeks prior to study enrollment.
• Ability to understand the study procedures, provide written informed consent, and comply with scheduled visits and study assessments.

Exclusion Criteria:

• Organic gastrointestinal diseases, such as gastrointestinal malignancy, intestinal obstruction, or inflammatory bowel disease.
• Severe cognitive impairment, including dementia that significantly interferes with study participation, or severe psychiatric disorders that affect compliance.
• Severe skin infection or open wounds at the treatment sites, including the thoracolumbar or sacral regions.
• Implanted electronic medical devices, such as cardiac pacemakers or deep brain stimulation (DBS) devices, unless deemed eligible after appropriate safety evaluation.
• Recent initiation or significant dose adjustment of medications that may affect gastrointestinal motility.
• Photosensitivity disorders or use of medications with significant photosensitizing effects.
• Significant dermatological diseases or skin cancer.
• Systemic lupus erythematosus.
• Acute illness at the time of enrollment.
• Abnormal blood pressure or fever at the time of treatment or enrollment.
• Active or untreated malignancy.
• Pregnancy.
• Significant physical abnormalities or sensory neurological abnormalities that may affect the safety or assessment of the intervention.
• Active infectious diseases.
• Coagulation disorders or clinically significant bleeding disorders.
• Presence of urinary or gastrointestinal stones.