The goal of this multi-site double blinded randomized sham-controlled Phase II clinical trial is to test a novel, relatively low cost, low risk, and potentially high impact therapeutic intervention in older adults who are at increased risk for Alzheimer's disease. The intervention involves transcranial and intranasal delivery of near infrared (NIR) light via light emitting diodes, aka photobiomodulation (PBM). The overall hypothesis, based on animal and pilot studies, is that exposure to NIR stimulation will have beneficial effects on brain health via influence on mitochondrial function as measured by changes in 31Phosphorous (31P) MRS-based markers of ATP, neural network changes in functional connectivity (rs-fMRI), and improved cognitive performance. To test this hypothesis, 168 older adults with subjective cognitive complaints, and a first-degree family history of Alzheimer's disease will be randomized to sham or real treatment groups. Neuroimaging and cognitive outcome measures will be obtained, before and after a 12-week intervention involving transcranial and intranasal NIR-PBM. The intervention protocol will involve "lab" and "home" sessions, and a 3 month post-intervention follow-up. This trial will determine: 1) whether NIR stimulation, relative to sham, improves performance on memory and executive tasks sensitive to hippocampal and frontal brain function in older adults with increased risk for Alzheimer's disease; 2) whether NIR stimulation, relative to sham, enhances brain function and connectivity measured by changes in MRS phosphorous ATP and resting state functional connectivity; and 3) how differences in demographic, neuroimaging, and Alzheimer-related risk factors influence the brain response to NIR stimulation versus sham in older adults with increased risk for Alzheimer's disease. Results will provide key insights into whether this novel NIR intervention can enhance cognition in older adults with increased risk for Alzheimer's disease and will provide the necessary data for a future Phase III randomized clinical trial.
This multi-site randomized sham-controlled trial proposes to test a novel, non-invasive, low risk and low-cost brain stimulation approach for enhancing cognition and brain health in cognitively normal older adults who are at increased risk for Alzheimer's disease. The intervention involves transcranial and intranasal delivery of near-infrared light (NIR; 808-904 nm) via light emitting diodes placed on the scalp or intranasally using a dosing that resulted in positive effects in our pilot studies. We plan to test the hypothesis that targeted NIR stimulation will have positive effects on brain health via influence on mitochondrial function as measured by changes in Magnetic Resonance Spectroscopy (MRS)-based markers of adenosine triphosphate (ATP), neural network changes as indexed by changes in functional connectivity based on resting state-fMRI (rs-fMRI), and improved cognitive performance. We plan to randomize 168 older adults, ages 65-89 years, to Active or Sham intervention conditions. To be included, participants must have subjective cognitive complaints, based on an index of Subjective Cognitive Impairment (SCI), and a family history of Alzheimer's disease in a first degree relative. Performance on standardized neuropsychological measures must be unimpaired psychometrically. The intervention itself will last for 12 weeks and include lab sessions (16 total) and daily at home sessions. In the lab, both transcranial and intranasal delivery of NIR light will be delivered using Medx and Vielight stimulation technologies, whereas the daily at home sessions will involve intranasal stimulation only. The sham and active conditions are identical in all respects except that sham devices will not deliver NIR stimulation. The primary outcome is an episodic memory measure involving spatial navigation that is linked to hippocampal function, sensitive to mild cognitive impairment (MCI) and Alzheimer's disease, and an analogue to the Morris Water maze. Secondary outcomes include executive function tasks and neuroimaging indicators of ATP function (31-P MRS) and connectivity changes based on resting state-fMRI. Exploratory outcomes include 'traditional' neuropsychological measures that are used clinically, along with measures and indices (e.g., apolipoprotein E \[APOE-4\] status) that might potentially mediate or moderate study outcome. Assessments will occur at baseline (Month 1), after 12 weeks of intervention (Month 4), and 3-month post intervention (Month 7). Imaging outcomes will be assessed only at baseline and at Month 4. Our primary aim is focused on cognition and will test whether NIR intervention, relative to sham, will produce pre-post improvement on tasks of recent memory (primary outcome) and executive function in older adults who are at increased risk for Alzheimer's disease. Our secondary aim is focused on neuroimaging and will test whether NIR intervention, relative to sham, will increase functional connectivity as indexed by resting state fMRI (secondary outcome) and enhance brain markers of MRS-ATP (secondary outcome). The 3rd aim is exploratory and will evaluate how baseline demographic, genetic, neuroimaging and other factors influence individual differences in cognitive outcome for NIR intervention.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
168
Near infrared light was delivered to the head using two MedX Rehab Console systems (MedX Health, 1116). Each MedX console included a control unit and 3 superluminous light emitting diode (LED) clusters. Each LED cluster (3MedX MCT502) consisted of 52 near infrared diodes and 9 visible red diodes. The 9 red diodes were deactivated. The energy delivered by each cluster was 1 joule \[J\]/cm2 in 45 sec at treatment wavelength of 870 nm per each 20 min. The LED cluster has an irradiance of 22.2 mW/cm2, treats an area of 22.48 cm2, with an energy density of 26.64/cm2 per cluster (total energy of 599J/cluster). During each session, the 6 clusters were arrayed on the scalp in 2 configurations, 20 minutes per array. Each configuration targeted 6 transcranial sites, guided by the 10-20 system, for a total of 12 sites during the 40-min session. Total energy delivered was 599J/cluster X 12 sites = 7188J. Intranasal stimulation was delivered using..
The MedX sham and Vielight interventions device are identical in all respects to the active device, except that the MedX console and diode clusters were modified to NOT deliver NIR light when turned on. The sham MedX devices were modified to deliver 'warmth', similar to that of the active devices. As with the active condition, a total of six sham interventions were given over a 12-week period, following the identical procedures described in the active condition
University of Arizona
Tucson, Arizona, United States
University of Florida McKnight Brain Institute
Gainesville, Florida, United States
Change in Active Group ARENA Composite Score Compared to Sham Group ARENA Composite Score
ARENA is a computer-based task of spatial memory-navigation that has been linked to hippocampal function and is a human analogue to the Morris water maze. ARENA consists of 9 learning trials and one final probe trial. On each learning trial, the path length and time to reach the target are recorded. On each probe trial, the percent time spent in the spatial quadrant where the target is located is recorded. The dependent variable is a total composite score consisting of mean z-scores for path length, time to reach the target, and %time in the target quadrant during the probe trial (Total Composite). Expected z-score values range from -3 to +3. A change score is computed by subtracting the baseline Total Composite z-score from the post-intervention Composite z scores. Higher scores mean better outcome.
Time frame: Baseline; Week 12
Change in Active Group Network Segregation Compared to Sham Group
Functional brain network segregation (FBNS), as assessed through functional brain MRI, measures the separation between resting state connectivity networks and is indexed by Fisher Z-transformed mean correlations. FBNS is calculated as follows: Mean Within-network correlation minus Mean Between-network correlation/Mean within-network correlation. The major outcome variable was change in segregation (FBNS) from baseline to post-intervention, which has a range from -1 to +1. Larger scores indicate increased network segregation, reflecting a better outcome.
Time frame: Baseline; Week 12
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