Key Takeaway
Systematic review of 36 studies (in vitro, animal, and clinical) found all included studies reported positive results for PBM in dementia, though clinical trials remain small and sometimes lack placebo controls.
Summary
This systematic review by Salehpour, Khademi, and Hamblin examined the evidence for photobiomodulation (PBM) therapy as a treatment for dementia. The authors searched literature from 1967 to 2020 following PRISMA guidelines, screening 10,473 initial articles and ultimately including 36 studies that met their criteria.
The included studies spanned three categories: 9 in vitro studies, 17 animal model studies, and 10 clinical studies in dementia patients. Notably, all included studies reported positive results for PBM in dementia-related outcomes. The review extracted data on light sources, wavelengths, power output, irradiance, treatment duration, dosage, and outcomes.
While the preclinical evidence was encouraging, the authors acknowledged that clinical studies were limited by small patient numbers and the lack of placebo controls in some cases. They concluded that the preliminary evidence of clinical benefit, the absence of adverse effects, and the ease of use of PBM warrant larger, well-controlled clinical trials to establish definitive efficacy for dementia treatment.
Methods
- Systematic literature search from 1967-2020
- PRISMA guidelines followed
- Screened 10,473 initial articles
- Included 36 studies meeting criteria
- Data extracted on wavelengths, power, irradiance, dosage, and outcomes
- Categorized into in vitro, animal, and clinical studies
Key Results
- All 36 included studies reported positive results
- 9 in vitro studies showed cellular-level benefits
- 17 animal studies demonstrated improvements in dementia models
- 10 clinical studies showed benefit in dementia patients
- No adverse effects reported across studies
- PBM appeared safe and easy to administer
Limitations
- Small patient numbers in clinical studies
- Lack of placebo controls in some clinical trials
- Possible publication bias (all positive results)
- Heterogeneous PBM parameters across studies
- Most clinical evidence still preliminary