Effect of trans-cranial near infrared light 1068 nm upon age-related memory status: a pilot study.

Background We present a pilot study of the Cerebrolite technology, where we explored the effect of multi-modality photo-biomodulation (PBM) therapy, with a peak wavelength of 1068 nm, upon motor function, memory and processing speed reversal in aged individuals who have been diagnosed with mild cognitive impairment (MCI) .Methods PBM therapy was performed at home, adopting the Cerebrolite Trans-cranial phototherapy device, an air-cooled light emitting diode LED pulse mounted inside the helmet, with a peak wavelength of 1068 nm, used for 6 min twice daily on age-matched middle-aged subjects. The FDA-approved computerised assessment tool ANAM was adopted to quantify a series of cognitive and motor activities in the treated groups.Results A signi ﬁ cant improvement in motor function, memory and processing speed was observed in MCI aged individuals with PBM- compared to placebo-treated group. No adverse effects were reported.Conclusions PBM therapy may be a promising new non-invasive approach for middle-aged individuals with MCI.


Background
Phototherapy, also known as photobiomodulation (PBM), refers to the use of non-thermal, non-invasive light to achieve a therapeutic outcome, and can apply to a variety of light-emitting devices of various wavelengths. It is the use of a low energy light source to elicit biological effects, also commonly referred to as Low-Level Light Therapy, LLLT, or Low-Intensity Light Therapy, LILT. Interest in recent advances in the use of light emitting diodes (LEDs) has led to their clinical application for a variety of medical and cosmetic uses [1]. Three distinct wavelength stretches of light, including blue (415nm), red (633nm), and near-infrared (830nm, 1060-80nm), have demonstrated e cacy or multiple therapeutic applications, [2].
A previous laboratory research study [3] has shown that human lymphocytes pre-irradiated with 1072 nm light are resistant against subsequent ultraviolet light toxicity. This was the optimal wavelength for cytoprotection in this study . Further studies have shown that this wavelength demonstrated a noninvasive bene cial effect, on spatial memory performance in a mouse model of premature ageing [4]. Furthermore, this wavelength was shown to elicit a range of positive effects upon cellular stress leading to reduced β-amyloid in a mouse model of Alzheimer's disease (AD) [5]. The mechanism of action involves photon absorption in the mitochondria electron-transport chain (cytochrome c oxidase), and upregulation of selective neuroprotective chaperone genes [5]. A recent pilot double blind, placebo-controlled study provided the rst evidence for the utility of the 1060-1080 nm wavelength range in treating agedependent neurodegenerative diseases. In this study, 28 daily 6-minute exposures (6 active, 3 controls) improved executive functions as measured by clock drawing, praxis memory, visual attention and task switching in patients with dementia [6].
In this present study, we explored, for the rst time, the potential for the bene cial effects of 1068 nm upon normal healthy middle-aged individuals.
Cerebrolite Trans-cranial phototherapy device An air cooled, LED helmet with a peak wavelength of 1068nm was used for 6 minutes twice daily. The peak power of the NIR light output was circa 37 Watts peak optical power achieved by using a unique pulse width modulation. The plan of the device with position of LED panels is shown in Figure 1.

Recruitment
Recruitment was over 3 years, age-matched participants (mean age 57 ± 10 years (Active) and 57 ± 8 years (Placebo) from the general population recruited from Barcelona in Spain and the north of England.
The Spanish volunteers were recruited sooner as the local Spanish regulator came to a decision similar to that in the UK, but a year earlier. A total of 27 participants completed the study. Recruitment was facilitated by word of mouth, newspaper advertisements and by posts on social media.

Randomisation
A computer-generated randomisation table was used. The odd numbers were assigned to individuals in the placebo group, and the even numbers were assigned to individuals in the active group.

Methods
Interested participants were either directed to the trial website (www.cerebrolite.com) or given a participant information sheet to read prior to their rst interview with an assessor. All assessors held a registered quali cation, to ensure compliance with protocol. Each participant was given the opportunity to ask questions and seek clarity regarding the requirements of the study before participation. Participants signed a consent form, a loan agreement, and provided base line data on their medication and general health. The participants were then assigned to an intervention according to a computer generated randomisation table to receive either an active or placebo device. Each participant was then assessed on 3 separate days, to minimise the impact on the results by day to day variations in cognitive performance as a positive outcome was likely to be small, but measurable.
The participants were then shown a Cerebrolite device and given the appropriate instructions on how to use the device and the participants were requested to use the Cerebrolite for at least 28 days. They were reassessed between 3 and 28 days later on 3 separate days. Some participants were only available over a period of a few weeks for re-assessment, and, therefore, the interval between test assessments was variable between individuals. The Cerebrolite was used twice daily until the last assessment was concluded.

Results
Thirty vearticipants were recruited and were assessed using the ANAM assessment tool, where n=27 completed the tasks and took part in follow-up (14 active and 13 placebo participants). Five of participants opted out because they found the assessments too challenging and three participants changed their mind. Due to participant time constraints 7 of the participants did not have 3 post treatment assessments, but only had 2 post-treatment assessment (4 in the active group and 3 in the placebo group).
In the active group there were 11 right-handed and 3 left-handed individuals and in the placebo group there were 11 right-handed and 2 left-handed individuals.
When comparing pre-treatment to post-treatment assessment scores and comparing the active to the placebo groups the following four selected modalities of the ANAM test achieved statistical signi cant improvement:  Tables 1 and  2 show mean changes across participants and corresponding p-values from paired-comparison t-tests. Also shown are counts of participants with results better after treatment and those with results worse after treatment. The sign test was applied to these counts and the resulting p-values are shown. The tables also show p-values from two-sample t-tests and Wilcoxon rank-sum tests, comparing changes in basic mean scores between the active and the placebo groups.  A review of the initial scores of the active and placebo groups indicated the groups were not balanced, which may have impacted upon the outcome measures. A further study with balanced groups is required.

Conclusions
Overall, this present study provides further evidence supporting the bene cial effects of 1068 nm PBM upon ageing and age-related brain dysfunctions, worthy of further exploration in larger cohort balanced group studies. HRA, we assessed that the project did not require HRA Approval, as healthy volunteers, were consented and seen at private non-NHS premises." The HRA stated "we are of the view that the project would more appropriately be classi ed and managed as service evaluation, rather than research intervention".
Informed consent was obtained from all individual participants included in the study.

Consent to publish
Not applicable; there is no participant identi able information in the manuscript.

Availability of data and materials
The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Competing interests G Dougal is a majority shareholder in Maculume Ltd
Funding Maculume Ltd provided the funding for the study.
Author's contributions G Dougal, responsible for the supervision, study design and manuscript composition of the study.