Laser acupuncture targets the gut-brain axis to tackle Parkinson's constipation and sleep troubles

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

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.