Dosimetry and Clinical Efficacy of Transcranial Photobiomodulation for Major Depression Disorder: Could they Guide Dosimetry for Alzheimer's Disease?

BACKGROUND: Major depressive disorder (MDD) is prevalent and has significant impact on individuals and society. Cognitive symptoms are frequent in MDD and insufficiently treated by antidepressant medications. Transcranial photobiomodulation (t-PBM) is a novel device therapy which shows promise as an antidepressant and pro-cognitive treatment. To date, despite the encouraging results, the optimal stimulation parameters of t-PBM to treat MDD are not established, and clinical studies are very heterogeneous in terms of these parameters. While the literature provides guidance on the appropriate fluence to achieve therapeutic results, little is known on the other parameters. OBJECTIVE: To evaluate the relationship between different parameters and the antidepressant effect of t-PBM. METHODS: We reviewed clinical studies on MDD and on depressive symptoms comorbid with other diseases. We calculated the standardized effect size of the change in symptoms severity before and after t-PBM and we performed a descriptive analysis of the reviewed papers. RESULTS: The greatest effect sizes for the antidepressant effect were found in studies using pulse-wave t-PBM with high peak irradiance (but low average irradiance) over large skin surface. One well-designed and sufficiently powered, double-blind, sham-controlled trial indicated that t-PBM with low irradiance over a small skin surface is ineffective to treat depression. CONCLUSION: The use of t-PBM for Alzheimer's disease and for dementia is still at its inception; these dosimetry lessons from the use of t-PBM for depression might serve as guidance.

Smoking during pregnancy and attention-deficit/hyperactivity disorder, predominantly inattentive type: a case-control study.

OBJECTIVE: Few previous studies assessed specifically attention-deficit/hyperactivity disorder, predominantly inattentive subtype (ADHD-I) in nonreferred samples. This study investigated the association between ADHD-I and prenatal exposure to nicotine. METHOD: In a case-control study performed between September 2002 and April 2005, we assessed a nonreferred Brazilian sample of 100 children and adolescents with ADHD-I and 100 non-ADHD controls (6-18 years old). Cases and controls, matched by gender and age, were screened using teacher reports in the Swanson, Nolan, and Pelham-IV (SNAP-IV) scale. They were systematically evaluated through structured diagnostic interviews. Prenatal exposure to nicotine and potential confounding factors were evaluated by direct interview with mothers. RESULTS: Adjusting for confounding factors (maternal ADHD, oppositional defiant disorder, birth weight, and alcohol use during pregnancy), children whose mothers smoked>or=10 cigarettes per day during pregnancy presented a significantly higher odds ratio for ADHD-I than children who were not exposed to nicotine during pregnancy (odds ratio 3.44; 95% confidence interval 1.17-10.06). Dimensional analyses showed significantly higher inattentive scores in subjects whose mothers smoked>or=10 cigarettes per day than in others after adjusting for confounding factors (p=.002). CONCLUSIONS: In a nonreferred sample, the authors expanded to ADHD-I previous findings documenting the association between prenatal exposure to nicotine and broadly defined ADHD in clinical samples.