Non-Pharmacological Interventions on Pain in Amyotrophic Lateral Sclerosis Patients: A Systematic Review and Meta-Analysis

Background: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder affecting upper and lower motor neurons. Some ALS patients exhibit concomitant nonmotor signs; thus, ALS is considered a multisystemic disorder. Pain is an important nonmotor symptom. Observational and case-control studies report high frequency of pain in ALS patients and it has been correlated with depression and quality of life. There are no specific scales for the assessment of pain and no randomized controlled trials (RCTs) regarding the drug management of pain in ALS. Aim: To systematically review the evidence for the nonpharmacological interventions (NPIs) in relieving pain in ALS, on March 2024, we searched the following databases: Pubmed, Scopus, Web of Science, and Cochrane. We also checked the bibliographies of trials identified to include further published or unpublished trials. Main results: A total of 1003 records were identified. Finally, five RCTs including 131 patients (64 in the intervention group and 67 in the control group) were included for meta-analysis. The interventions of the included RCTs consisted of muscle exercise, combined aerobics-strength intervention, and osteopathic manual treatment. The meta-analysis did not find a statistically significant difference in favor of NPIs for alleviating pain in ALS patients. Conclusions: ALS has a fulminant course and irreversibly leads to death. Pain in ALS patients, although a common nonmotor symptom, is often unrecognized and undertreated, and this is underlined by the lack of any RCTs on drug therapy for pain. Albeit NPIs are considered safe, as adverse effects are rarely reported, this systematic review did not provide sufficient evidence for a beneficial effect on pain. The scarceness of relevant literature highlights the need for future studies, with larger samples, more homogeneous in terms of interventions and population characteristics (stage of disease), and better choice of measurement scales to further investigate the efficacy, if any, of various pain interventions in ALS patients.