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Research Article Volume 19 Issue 3
Systemic neurobehavioral effects of cervical low-level laser therapy on sleep, anxiety, and depressive symptoms
Cesar Lara, Calixto Machado, Travis Sammons, Steve Shanks
Received: April 25, 2026 | Published: May 12, 2026
Citation: Lara C, Machado C, Sammons T, et al. Systemic neurobehavioral effects of cervical low-level laser therapy on sleep, anxiety, and depressive symptoms. Int J Complement Alt Med. 2026;19(3):124-129. DOI: 10.15406/ijcam.2026.19.00772
Abstract
This controlled study evaluated the effects of coherent low-level laser therapy (LLLT) on sleep quality, mood, anxiety, and depression in adults with chronic wellness complaints. Treatment was applied to the carotid sheath region of the neck, a site overlying the common carotid artery, internal jugular vein, and vagus nerve. Ten participants were randomized to active laser treatment (n = 5) or placebo LED exposure (n = 5). The active-treatment group demonstrated clinically meaningful between-group improvements in GAD-7, BDI, and SQS scores relative to placebo. Quantitative electroencephalography (qEEG) findings were concordant with clinical outcomes, revealing increased alpha power, reduced theta predominance, and improved interhemispheric coherence in the laser group— neurophysiologic signatures consistent with enhanced cortical organization, improved arousal regulation, and reduced neural inefficiency. These preliminary findings suggest that LLLT delivered to the carotid sheath region may produce measurable systemic effects through an integrated vascular-neural mechanism encompassing vagal neuromodulation, circulating extracellular mitochondrial signaling, carotid arterial transport toward the brain, and oxyhemoglobin-mediated support of cerebrovascular physiology.
Keywords: low-level laser therapy, LLLT, qEEG, alpha power, coherence, sleep quality, anxiety, depression, vagal neuromodulation, extracellular mitochondria
©2026 Lara, et al. This is an open access article distributed under the terms of the, which permits unrestricted use, distribution, and build upon your work non-commercially.