Department of Psychology, The Chinese University of Hong Kong, Shatin, Hong Kong.
Research Centre for Neuropsychological Well-Being, The Chinese University of Hong Kong, Shatin, Hong Kong.
J Alzheimers Dis. 2024;101(1):321-335. doi: 10.3233/JAD-240473.
Alzheimer's disease has become increasingly prevalent among the older population, leading to significant social and economic burdens. Transcranial photobiomodulation (tPBM) has shown promise as a cognitive intervention for enhancing cognitive efficiency in healthy older adults, and individuals with mild cognitive impairment and Alzheimer's disease. However, determining the optimal tPBM dosage is crucial for ensuring effective and efficient intervention.
This study aimed to compare the effects of different dosages in a single tPBM session on cognitive efficiency in healthy older adults.
In this randomized controlled trial, 88 healthy older participants were assigned to either a single dose (irradiance = 30 mW/cm2, fluence = 10.8 J/cm2; n = 44) or a double dose (irradiance = 30 mW/cm2, fluence = 21.6 J/cm2; n = 44) tPBM session. Cognitive efficiency was assessed using functional near-infrared spectroscopy during a visual working memory span task.
The single dose group exhibited significantly greater cognitive efficiency enhancement, indicated by a more pronounced reduction in oxygenated hemoglobin during a challenging task level (span level 9) (p = 0.021, d = 0.50), and better working memory task performance (p = 0.045, d = 0.31). Furthermore, participants with better visuospatial abilities demonstrated greater improvement after a single dose (r = -0.42, p = 0.004). In contrast, participants with varying cognitive function did not exhibit additional benefits from a double dose (r = -0.22-0.15, p = 0.16-0.95).
These findings suggest that higher tPBM dosages may not necessarily result in superior cognitive improvement in older adults.
阿尔茨海默病在老年人群中越来越普遍，给社会和经济带来了重大负担。经颅光生物调节（tPBM）已被证明是一种增强认知效率的认知干预措施，适用于健康老年人以及轻度认知障碍和阿尔茨海默病患者。然而，确定最佳 tPBM 剂量对于确保干预的有效性和高效性至关重要。
本研究旨在比较单次 tPBM 治疗中不同剂量对健康老年人认知效率的影响。
在这项随机对照试验中，88 名健康老年人被分为单次剂量组（辐照度=30mW/cm2，通量=10.8J/cm2；n=44）或双剂量组（辐照度=30mW/cm2，通量=21.6J/cm2；n=44）。在视觉工作记忆跨度任务中，使用功能近红外光谱技术评估认知效率。
单次剂量组表现出更显著的认知效率增强，在挑战性任务水平（跨度水平 9）下，氧合血红蛋白的减少更为明显（p=0.021，d=0.50），工作记忆任务表现更好（p=0.045，d=0.31）。此外，具有更好的视空间能力的参与者在单次剂量后表现出更大的改善（r=-0.42，p=0.004）。相比之下，认知功能不同的参与者从双剂量中没有获得额外的益处（r=-0.22-0.15，p=0.16-0.95）。
这些发现表明，较高的 tPBM 剂量不一定会导致老年人认知改善更优。
