See The Light
Posted by apgaylard on October 27, 2007
Yesterday the BBC, in what used to pass for a news programme, ran a piece entitled “Worries over ‘winter blues’“. Aside from trivialising a very real and distressing condition, Seasonal Affective Disorder (SAD), it was nothing more than a sales pitch for a dubious “medical” treatment.
The sales pitch was provided by Pauline Allen of the Sound Learning Centre. This seems to be a private clinic of sorts working out of a converted terraced villa in London. Pauline Allen is its principal. The information provided on their website on her “qualifications” is illuminating. She has no medical qualifications. Everything mentioned is training in specific therapies, not a recognised qualification among them. Some of the therapies are also definitely nonsense (Brain Gym, for one). There are also lots of mentions of the trainers by names, invoking their special authority. This information does not by itself mean that their SAD therapy is useless. But there are sufficient signs to put a sensible person on guard.
Now to the therapy: it is called “Lightwave Stimulation” (LWS). It also goes by other names: Downing Technique, Lumatron therapy, Ocular light therapy, Photron therapy.
This was introduced by the journalist, Richard Westcott. He said, of SAD sufferers: “… For many this is the answer, test what light you are missing and give a colour top-up (dim red light shown) the extra light triggers the hormones that can make you happy …”
We were then introduced to a happy customer for a testimonial. Pauline Allen can be heard asking the chap: “… Yellow – how does this one make you feel?” as he looks into a dim yellow light. The journalist ultimately offers a concluding remark along the lines that the: “… wet and cold summer has left our “light reserves” in the red.”
The wrong-headed pseudoscience is clear. No one is “missing” any particular light colour. We don’t store light, have light reserves, or need them to be topped up. Where does this nonsense come from?
Consulting the Sound Learning Centre’s web page on their light therapies makes this clear. LWS is based on the notion that “… a photocurrent deficit …” can arise and is responsible for the range of conditions listed below.
learning disabilities, poor memory, poor concentration;
poor physical co-ordination and performance;
light sensitivity, poor peripheral vision, night blindness;
hyperactivity, sleeping problems, fatigue, mental fogginess, headaches;
emotional difficulties, including anxiety and depression;
Seasonal Affective Disorder (SAD).
It is hard to imagine that a single light based therapy could treat both light sensitivity, and night blindness let alone the rest of this rather varied list. More alarm bells!
The therapy is then: “… stimulation with appropriate coloured light through the eyes [to] increase the ability of the neuro-visual pathways to transmit photocurrent to the different parts of the brain and reduce this deficit.”
This is just nonsense. It may sound like science, but it isn’t. The way colour vision has been found to work is that the eye’s colour receptors (cones) come in three types. Each type has a distinctive pigment that enables them to respond to different parts of the visible spectrum (red, green and blue-violet). A particular colour stimulates all three types to varying degrees; the pattern of these responses determines the colour perceived. This partly processed colour “signal” then travels down the optic nerve into the brain. This eventually passes into the primary visual cortex for complex three-colour processing.
So where is the description of LWS wrong? For a start, although the signal in the optic nerve is electrical in nature, no one calls it a “photocurrent“. The only place I have come across this term is to describe the current that flows though a photosensitive electronic device when exposed to a radiant source.
More fundamentally, there is no place in what is known about colour vision for long-term deficits in this signal being stored in the brain. There is no place for ideas about not seeing particular colours causing a degradation of the optic, or any other, nerve. If there were, exposure to “ordinary” light would be fine as it contains all the colours of the rainbow!
So, what is clear is that the explanation provided for how this therapy works is nonsense. It doesn’t mean, of course, that it cannot work. However I’ve not been able to find any good evidence that it does. Testimonials don’t count, of course, as they are a completely biased sample (They miss everyone who gets no benefit from a therapy) and are further compromised by the placebo effect.
“… We have been unable to identify any scientific trials of lightwave stimulation for people with autism published in peer-reviewed journals …”
“…The only scientific trial of any light therapy for people with autism we could identify was for the treatment of seasonal affective disorder.”
“… There is currently no scientifically valid or reliable evidence to support the use of light wave stimulation for people with autism spectrum disorders.”
“… However we believe this lack of evidence does not prove or disprove the effectiveness of light wave stimulation for people with autistic spectrum disorders. It may simply show that no research has been conducted to date.”
It is a digression, but nevertheless it is worrying that the Sound Learning Centre are pitching this as a treatment for people with autism, given the dearth of evidence noted above. Particularly as this therapy is provided for a price. Again, this should set off alarm bells when they talk about treating SAD.
So, what was the reference to the treatment of SAD that Research Autism found? It was a paper that assessed the response of two people with learning disability to treatment for SAD. It was also: “… a trial of treatment with bright artificial light …”; not LWS anyway.
The really sad thing about this piece though was the failure to mention light treatments that are supported by at least some reasonable evidence. These include bright light therapy and dawn simulation. A review paper concluded that:
“… This analysis of randomized, controlled trials suggests that bright light treatment and dawn simulation for seasonal affective disorder and bright light for nonseasonal depression are efficacious, with effect sizes equivalent to those in most antidepressant pharmacotherapy trials …”
It is worth noting that their definition of bright light treatment of seasonal affective disorder was “… a minimum of 4 days of at least 3,000 lux-hours (e.g., 1,500 lux for 2 hours or 3,000 lux for 1 hour) …”. For dawn simulation studies this was: “… increasing light exposure from 0 to 200-300 lux over 1.0-2.5 hours …”
Another review noted that “strong” light (6000 lux or more) was more effective than “medium” light (1700 to 3500 lux) and this was, in turn better than “dim” light (600 lux or less). The wavelengths of light included full spectrum light with UV wavelengths, cool-white or full spectrum light without UV wavelengths, red wavelengths, and blue/green/yellow wavelengths. No individual “colours” based on an assessment of the patient, unlike LWS.
It has been reported that there is some evidence emerging to suggest “blue” wavelengths may be disproportionately effective; but again this is not the ‘choose a colour’ approach of LWS.
There is a good summary of the current state of research here. It’s provided by a manufacturer of light systems, so some caution is advisable, but seems to provide reasonable access to proper scientific studies.
So, what are we to make of this? Well it seems that there is no real evidence to support the use of this therapy for SAD. There is certainly no way it can work in the way the Sound Learning Centre say.
However, there are light based therapies that have some evidence to say that they may work. By producing what was effectively a free infomercial, at public expense, for a private clinic instead of highlighting these treatments (or even consulting its own website!) the BBC have done a distinct disservice to those who suffer from this distressing affliction. Even the Daily Mail has provided better coverage of this topic: talking to people with proper qualifications and discussing realistic treatments.
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