That is a slightly unfair comparison to use with Low Level Laser Therapy (Cold Laser Therapy, Photobiomodulation, Transmeatal Cochlear Laser or Laser Biostimulation), however the claims that are often very strongly made for the use of LLLT in Tinnitus are probably in need of some of the 'Cold light of reality' shining upon them. Whilst a treatment for one illness may be very effective, it is unsafe to assume that the same treatment will be equally effective in a completely different illness. And yet that is what is suggested in the case of LLLT, a treatment whose main indicators are in soft tissue injury, chronic pain and wound care is now being suggested as a 'cure' for Tinnitus.
Proposed Mechanism of Action
Taken from the article by Barry Keate on the Arches Formula Site
'LLLT was first developed for inner ear diseases by Uwe Witt, MD of Hamburg, Germany in the 1980’s. Lutz Wilden, MD, of the Center for Low Level Laser Therapy in Bad Fussing, Germany developed it further and brought it to a wide range of patients. Dr. Wilden’s central thesis is that laser energy in the red and near infrared light spectrum is capable of penetrating tissue. It stimulates mitochondria in the cells to produce energy through the production of ATP (adenosine triphosphate). Mitochondria are the power supplies of all cells; they metabolize (burn) fuel and produce energy for the cell in the form of ATP. In stimulating the mitochondria, laser therapy can repair damaged tissue and return cells to a healthy state, reversing many degenerative conditions.'
Controversies
Although there is evidence for the use of Photobiomodulation in surface injuries and possibly deeper sources of chronic pain there is no evidence that this translates to the sort of neural regeneration that would be required to cause the effects claimed by Dr Wildens and other proponents. Of interest is that Dr Wildens et al are yet to publish a peer-reviewed academic paper demonstrating their findings, they have been presented papers at conference but this carries nowhere near the same weight. It is also doubtful that laser energy is capable of penetrating to the depth of the inner ear or of doing anything when it gets there. The inner ear or Cochlear is embedded in the Petrous (stone-like) portion of temporal bone which as the name suggests is extremely dense.
As you can see, whether applied directly to the mastoid process (pointy bone behind the external ear) or directed straight down the ear canal the cold laser has quite a journey ahead of it, the likelyhood of the energy being absorbed or dissipated would appear to be very high.
Some practitioners and researchers argue that a great deal of the research that has been done has been of insufficient repetition or laser strength or wavelength to achieve the desired and claimed effects, however they also seem to be perfectly happy to sell home laser systems direct to the public with the same limited power levels. (I've been informed by a customer of Dr Wildens that the laser he sells is stronger than average at around 30mW, although I could find no evidence of this on the site).
The Evidence
Taken in order of publication;
Partheniadis-Stumpf et al used a combined approach using Tebonin (a form of Ginko-Biloba supplement) and laser treatment and failed to find any evidence of benefit although their sample size was quite small, abstract available here
With a slightly higher number of participants Shiomi et al appeared to show some degree of benefit, however their study suffered from a lack of a control group, abstract available here
Mirz et al with a similar number to Shiomi but using a well structured randomized double blind placebo-control trial were unable to find any statistically significant evidence of benefit using the active laser and concluded that previous reports of benefit were simply placebo effect, abstract available here
Once again using a combination of Ginko (this time in the form of EGb 761) and laser Hahn et al. with 120 study participants reported an improvement in just over 50%, however this study was once again marred by the lack of any control group, abstract available here
Despite again failing to supply a control group and with a small study size than Hahn, Nakashima et al found no benefit whatsoever from the use of 60mW laser irradiation, abstract available here
Tauber et al looked at whether any effect of the laser was dose-dependant in terms of wavelength and strength of laser, again without a control group. They report 15/35 experiencing significant improvement, with two subjects reporting no Tinnitus after six months. They acknowledge the need for large double-blind placebo-controlled studies to confirm and support their findings, abstract available here
Siedentopf et al conducted an interesting study which appears to show central changes occurring in regions of the brain that have been associated with Tinnitus generation only when an active rather than placebo laser is used. Unfortunately the size of the study and detailed methodology are not available in the abstract. It is also worthy of note that fMRI measures are only indicative of activity and may not relate to the stimulus presented, abstract available here
In 2008 Hahn et al again revisited soft-laser therapy in comparison with a number of drug and physical therapies. By dividing the 150 participants into seven treatments arms they substantially weakened the power of each separate arm, however their conclusion was that 'The most effective treatment was defined as a combination of Cavinton and physiotherapy', the outcome for soft laser is not mentioned in the abstract, which is available here
Gungor et al. found using a laser strength, wavelength and duration of treatment that is often suggested by LLLT proponents to be insufficient (5mW, 650nM, 15 mins 1/day for 1 week) that in all three of their measures subjects exposed to active laser rather than placebo improved by approximately 50%. The abstract does not mention the size of the control group used. Abstract available here
In a recent study with very small active and control arms Cudia et al again using a 5mW laser but over a much longer treatment period (three months) found that the treatment group experienced 26% more improvement than the control group. It should be noted that no reason is given for the greater size of the treatment arm of the study (26 compared to 20 in the control) and that the difference in daily intervention was not controlled for. 26% would correspond well with a placebo effect, abstract available here
For completeness and background I've included the full search results from the NHS Library for Health and information on the proposed mechanism for Photobiomodulation here. Dr Wilden's take on this is available here, although it is important to note that although it looks like an academic paper it has NOT been peer reviewed or published in a journal of note. Also, given the prevalence of Ginko-Biloba in these studies used alongside laser therapy (and the willingness of online companies such as Arches to sell you the supplement) it may be useful to reflect on the evidence from this very well designed and large scale study, funded by the British Tinnitus Association.
Conclusions
There appears to be a very limited evidence base for the use of LLLT in Tinnitus, and where it does exist there are often significant methodological flaws which act to weaken the evidence. Despite concerns from the proponents of LLLT that sufficient exposure time, strength or correct wavelength have not been used in negative studies this does not alter the apparent fact that there is an absence of peer reviewed evidence using the criteria they propose.
The mechanism of action proposed for LLLT has a degree of surface validity, although it remains controversial even in the areas where it is normally employed. In the ear it is claimed that the laser is capable of both penetrating to the neuronal tissue of the Cochlea and facilitating regeneration of damaged nerve tissue, thus improving hearing and reducing Tinnitus. Two extraordinary claims, both in need of extraordinary evidence which currently does not appear to exist.
I should emphasise, particularly in light of the current court case between the British Chiropractic Association and Simon Singh that I am not in any way suggesting that major practitioners of LLLT are being disingenuous in offering it as a treatment for Tinnitus. I suspect that most of them are entirely persuaded by the science and their own experience. However in all likelihood their sincerity is a product of a number of logical and methodological fallacies. Selection bias, in that only the very motivated and well-heeled can afford the high fees often charged (3000 euro's is not uncommon). Regression to the mean, i.e. people tend to seek out radical treatments when in extremis, however most chronic conditions can only remain at their peak severity for a short time then regress to their background level, particularly true with Tinnitus (Hallam, 1970). And finally confirmation bias, i.e. the tendency we all have to only remember the positive feedback, and forget those who are dissatisfied or simply don't return for further treatment.
Further Reading
http://www.tinnitusformula.com/infocenter/articles/treatments/LLLT.aspx
http://www.dr-wilden.de/en/
http://www.laser.nu/tlc/tinnitusEnglish.htm
http://www.laserpartner.org/lasp/web/en/2000/0004.htm
http://www.rnid.org.uk/community/forums/tinnitus/dr_wilden/?pn=1
