20 replies to this topic

[gwern]

Some time ago, lostfalco got me interested in the topic of low-level light treatment (weak near-infrared light administered to the head) with his thread and donated money for me to try out a device.

 

While skeptical (because come on, LLLT sounds like the stupidest thing in the world and 100% snake oil), I didn't see any harm in trying, and on 7 September 2013, I began sporadically (non-randomized) using a 48-LED set on my head. In between, I also analyzed a blind self-experiment run by Nattzor which found large benefits to his reaction-time.

 

I recently compiled my own data, leaving me with 329 days of data. The response variable 'MP' is a little self-rating of my own devising in which for 2.5 years I've asked myself at the end of each day whether I did more, the usual, or less work done that day than average (2=below-average, 3=average, 4=above-average); it's ad hoc, but in some factor analyses I've been playing with, it seems to load on a lot of other variables I've measured, so I think it's meaningful. The results are that (correcting for the magnesium self-experiment I was running during the time period which did not turn out too great) days on which I happened to use my LED device for LLLT were much better than regular days. Below is a graph showing the entire MP dataseries with LOESS-smoothed lines showing LLLT vs non-LLLT days:

 

 

The correlation is fairly large (r=0.185 or d=0.46 if you prefer) and statistically-significant (p=0.0006).

 

I have no particularly compelling story for why this might be a correlation and not causation. It could be placebo, but I assumed the LLLT was not working and was going to throw out the LED set until I ran the numbers just in case. It could be selection effect (days on which I bothered to use the annoying LED set are better days) but then I'd expect the off-days to be below-average and compared to the 2 years of trendline before, there doesn't seem like much of a fall.

 

So, I have started a randomized experiment; should take 2 months, given the size of the correlation. If that turns out to be successful too, I'll have to look into methods of blinding - for example, some sort of electronic doohickey which turns on randomly half the time and which records whether it's on somewhere one can't see (then one hooks up the LED, turns the doohickey 'on', and applies directly to forehead, checking the next morning to see whether it was really on or off).

 

Below is a link to the raw data, and the R code for my analysis & graph:

# http://dl.dropboxusercontent.com/u/85192141/2014-08-03-lllt-correlation.csv
lllt <- read.csv("2014-08-03-lllt-correlation.csv")
summary(lm(MP ~ LLLT + as.logical(Magnesium.citrate) + as.integer(Date) + as.logical(Magnesium.citrate):as.integer(Date), data=lllt))
# ...Coefficients:
#                                                        Estimate   Std. Error  t value   Pr(>|t|)
# (Intercept)                                         4.037702597  0.616058589  6.55409 5.0282e-10
# LLLTTRUE                                            0.330923350  0.095939634  3.44929 0.00069087
# as.logical(Magnesium.citrate)TRUE                   0.963379487  0.842463568  1.14353 0.25424378
# as.integer(Date)                                   -0.001269089  0.000880949 -1.44059 0.15132856
# as.logical(Magnesium.citrate)TRUE:as.integer(Date) -0.001765953  0.001213804 -1.45489 0.14733212

llltImputed <- lllt
llltImputed[is.na(llltImputed)] <- 0
llltImputed[llltImputed$MP == 0,]$MP <- 3 # clean up an outlier

summary(lm(MP ~ LLLT + as.logical(Magnesium.citrate) + as.integer(Date) + as.logical(Magnesium.citrate):as.integer(Date), data=llltImputed))
# ...Coefficients:
#                                                        Estimate   Std. Error  t value   Pr(>|t|)
# (Intercept)                                         2.959172295  0.049016571 60.37085 < 2.22e-16
# LLLT                                                0.336886970  0.083731179  4.02344 6.2212e-05
# as.logical(Magnesium.citrate)TRUE                   2.155586397  0.619675529  3.47857 0.00052845
# as.integer(Date)                                    0.000181441  0.000103582  1.75166 0.08017565
# as.logical(Magnesium.citrate)TRUE:as.integer(Date) -0.003373682  0.000904342 -3.73054 0.00020314

power.t.test(power=0.8, delta=(0.336886970 / sd(lllt$MP, na.rm=TRUE)), type="paired", alternative="one.sided")
#
#      Paired t test power calculation
#
#               n = 30.1804294
#           delta = 0.463483435
#              sd = 1
#       sig.level = 0.05
#           power = 0.8
#     alternative = one.sided
#
# NOTE: n is number of *pairs*, sd is std.dev. of *differences* within pairs

library(ggplot2)
llltImputed$Date <- as.Date(llltImputed$Date)
ggplot(data = llltImputed, aes(x=Date, y=MP, col=as.logical(llltImputed$LLLT))) +
 geom_point(size=I(3)) +
 stat_smooth() +
 scale_colour_manual(values=c("gray49", "green"),
                     name = "LLLT")

[Barfly]

Hi, thank you very much for sharing this, amazing work !

 

How long were your sessions, how many minutes per spot were you using the device and how many days per week?

 

Also, I am surprised to see that usage of LLLT had immediate beneficial effect on your productivity, if analogy between LLLT and exercise is correct that I would expect your baseline productivity to slowly increase over months with little variations over single days.

 

So, if LLLT has immediate positive effects that I guess using it in the morning would be most beneficial, so I am wondering what reasons made Lostfalco to decide on lasering before sleep?

 

Thank you very much !

 

 

 

 

[typ3z3r0]

Blinding seems as if it'd be hard to do, unless the LEDs on your device don't heat up when applied to your head.

[Raza]

Cool, thanks for sharing!

Edited by Raza, 04 August 2014 - 10:42 AM.

[gwern]

How long were your sessions, how many minutes per spot were you using the device and how many days per week?
 
Also, I am surprised to see that usage of LLLT had immediate beneficial effect on your productivity, if analogy between LLLT and exercise is correct that I would expect your baseline productivity to slowly increase over months with little variations over single days.
 
So, if LLLT has immediate positive effects that I guess using it in the morning would be most beneficial, so I am wondering what reasons made Lostfalco to decide on lasering before sleep?
 
Thank you very much !

 

My sessions were 10-15 minutes, with maybe 2-5 minutes a spot. The number of days per week varied; if you're curious, look at the data. I did avoid ever doing LLLT two days in a row, though, as lostfalco claimed that was bad and could lead to overstimulation.
 
I'm not too surprised. LLLT is not exercise, and at least one effect happens immediately: most people report feeling strangely and abruptly tired the first time they use LLLT on their head, as did I. The postulated mechanism (activating cytochrome-c to increase mitochondrial activity to increase available ATP to cellular activity) could also happen very fast, unlike the slow repair of tissue or secretion of BDNF which are connected to physical exercise.
 
Yes, probably. The way I did it was that if I hadn't gotten around to it by 2PM, I gave up on LLLT that day. Right now with the randomization, I'm being more rigid and trying to do the randomization before or during breakfast.

Blinding seems as if it'd be hard to do, unless the LEDs on your device don't heat up when applied to your head.

The light is near-infrared, so it's effectively impossible to see (you can do it in complete darkness and looking very carefully for a reddish tint in the LEDs). The device doesn't heat up significantly unless I run it for a while, and that may simply be warming up due to my hand holding it. Blinding seems doable, if I could just figure out how to turn it on randomly.

Edited by gwern, 04 August 2014 - 04:40 PM.

[NeuroGeneration]

Maybe you could use ifttt.com in conjunction with a Belkin outlet switch. Set the "if" to be related to something random, or that you wouldn't know about on your own (another city's rain / sun forecast, where it's roughly 50/50? Just an idea). The "then" will be turning on the outlet.

 

Then, set up another recipe, where "if the Belkin outlet is turned on, add a log to a Google spreadsheet".

 

I'm sure there are many other permutations, but that's one that came to mind.

[typ3z3r0]

The light is near-infrared, so it's effectively impossible to see (you can do it in complete darkness and looking very carefully for a reddish tint in the LEDs). The device doesn't heat up significantly unless I run it for a while, and that may simply be warming up due to my hand holding it. Blinding seems doable, if I could just figure out how to turn it on randomly.

 

 

Heh. Okay. My 48 LED devices LEDs heat up quite a few after 5 or so minutes of being applied on my head. :/

[gwern]

Maybe you could use ifttt.com in conjunction with a Belkin outlet switch. Set the "if" to be related to something random, or that you wouldn't know about on your own (another city's rain / sun forecast, where it's roughly 50/50? Just an idea). The "then" will be turning on the outlet.
 
Then, set up another recipe, where "if the Belkin outlet is turned on, add a log to a Google spreadsheet".
 
I'm sure there are many other permutations, but that's one that came to mind.

I''m sure there must be appropriate gadgets, but I'm not sure what. What Belkin outlet are you thinking of? I googled the brand but all the examples seemed to be regular power strips, and not programmable things which did tricks like turn on or off based on an API.
 

Heh. Okay. My 48 LED devices LEDs heat up quite a few after 5 or so minutes of being applied on my head. :/

Maybe, but is that because you're holding it or because of your head? Does it heat up substantially if you just let it sit on the table for 5 minutes?

[typ3z3r0]

Substantially, after having it pressed against my forehead or hair. I have to actually stop because otherwise it makes my hair feel funny, and because it's also too uncomfortable, and I don't want to be burnt. haha.I guess I could try longer breaks between applications. :P

[gwern]

Huh. Mine certainly doesn't ever make me worry about being burnt or feel uncomfortable. Your LED thing must be more powerful than mine.

[NeuroGeneration]

 

Maybe you could use ifttt.com in conjunction with a Belkin outlet switch. Set the "if" to be related to something random, or that you wouldn't know about on your own (another city's rain / sun forecast, where it's roughly 50/50? Just an idea). The "then" will be turning on the outlet.
 
Then, set up another recipe, where "if the Belkin outlet is turned on, add a log to a Google spreadsheet".
 
I'm sure there are many other permutations, but that's one that came to mind.

I''m sure there must be appropriate gadgets, but I'm not sure what. What Belkin outlet are you thinking of? I googled the brand but all the examples seemed to be regular power strips, and not programmable things which did tricks like turn on or off based on an API.

 

 

 

 

@gwern – it's the Belkin WeMo series: http://www.belkin.co...ome-automation/

 

Specifically, this item: http://www.belkin.co...3E63DAFC39E81C/

 

In terms of IFTTT, you could do something even simpler than I originally recommended. Create a Google Calendar, that you sync with IFTTT, but never check until the end of your study. Randomly add tagged events to certain days, i.e., "#LLLT from 10am-10:30am". Create a rule in IFTTT: "if there's a Google Calendar event tagged with #LLLT, turn on WeMo switch."

 

In this case, you have the trigger to turn it on and the log of when it was on, all in one simple Google calendar – and no reason or need to check if it was on until the very end of your study.

[basicallyyes]

I did the LLLT protocol exactly as was stated (with PQQ etc) and didn't really notice a difference. I mean no disrespect when I say this: If you look at the posting history of most of the people who hyped this (this is not directed at  gwern) they have a pattern of talking about many things as being extraordinary. So either they are responding in ways that most other people don't or they tend to exaggerate things a bit. 

[Nattzor]

I (who did a test which gwern has written about (linked in first post)) did not feel a thing on LLLT, still got effect. People need to realise that most noots are not some kind of stimulant that you feel, you need to measure things.

[Raisinthehouse]

I did the LLLT protocol exactly as was stated (with PQQ etc) and didn't really notice a difference. I mean no disrespect when I say this: If you look at the posting history of most of the people who hyped this (this is not directed at  gwern) they have a pattern of talking about many things as being extraordinary. So either they are responding in ways that most other people don't or they tend to exaggerate things a bit. 

 

So because you "felt" no effects. Everyone who measures and reports results is wrong or exaggerating......gotcha.

[gwern]

I've posted my writeup to http://www.gwern.net/Nootropics#lllt and added an additional factor-analysis which weakens the results a bit.

 

@gwern – it's the Belkin WeMo series: http://www.belkin.co...ome-automation/
 
Specifically, this item: http://www.belkin.co...3E63DAFC39E81C/
 
In terms of IFTTT, you could do something even simpler than I originally recommended. Create a Google Calendar, that you sync with IFTTT, but never check until the end of your study. Randomly add tagged events to certain days, i.e., "#LLLT from 10am-10:30am".

 

I see what you mean. A network-capable switch would probably work, yes... Your Google Calendar suggestion isn't good since it requires you to break blinding, but it's probably easy to write a program to connect to the switch, flip a bit, and record whether it was turned on or not, and to put tape over the indicator lights.

[NeuroGeneration]

How does the google calendar require you to break blinding? Just have a friend – or random person, for that matter  – enter the events into the calendar for you.

[platypus]

So basically exposing your head to sunlight should have the same effect? Actually probably a stronger one as the infrared radiation from the sun is so strong.

[gwern]

Dunno. Sunlight is spread out over a very wide spectrum, even if it is brighter.

[hephaestus]

I don't think you need any special network connected switch for this. You just need a plain old switch that has the on and off markings obscured.

[tunt01]

Don't really care about LLLT very much but thanks for the wonderful R exercise and dataset!

[basicallyyes]

 

I did the LLLT protocol exactly as was stated (with PQQ etc) and didn't really notice a difference. I mean no disrespect when I say this: If you look at the posting history of most of the people who hyped this (this is not directed at  gwern) they have a pattern of talking about many things as being extraordinary. So either they are responding in ways that most other people don't or they tend to exaggerate things a bit. 

 

So because you "felt" no effects. Everyone who measures and reports results is wrong or exaggerating......gotcha.

 

 

You put words in my mouth and exaggerated what I said to make my opinion sound ridiculous, acting like that in real life will ruin relationships.

Edited by basicallyyes, 24 August 2014 - 09:04 PM.