Low level laser therapy of tinnitus - a case for the dentist?

Jan Tunér DDS, Swedish Laser-Medical Society (www.laser.nu)
Jan.tuner@swipnet.se

Is the tinnitus always in the ear?

The following is an edited version of a chapter from the book “Laser therapy, clinical practice and scientific background” (Prima Books of Sweden, 2002, www.prima-books.com)

A new and promising indication for laser therapy is tinnitus. This inner ear disease is a growing problem in noisy modern society and the number of persons suffering from tinnitus is increasing. Traditional treatment for tinnitus is psychological support or various masking procedures. Acupuncture and ginko extracts have been tried with limited success. Laser therapy alone offers a new and promising treatment modality. Irradiation is given partly through the meatus, partly behind the ear, provided the problem really is located in the inner ear. Since the bone behind the ear is very compact, high power densities and prolonged treatment times are necessary to reach a sufficient dose in the inner ear when irradiating through bone.

Literature:
Witt [1084] is one of the pioneers in this field, but to the knowledge of the authors his results have not been published in any peer-review journal. Witt combines infusion of Gingko biloba (Egb 761, 17.5 mg dry extract per 5 ml ampoule) and laser. This may be a favorable combination but an evaluation of the contribution of the laser is not possible. More than 500 patients have been treated since 1989 and Witt claims that more than 60% of the patients have reached a considerable or total relief. The laser used is a combination of a HeNe laser with 12 mW output and a GaAs laser with 5 laser diodes each with 15 mW average power and output was used. Treatment technique is not stated.
Swoboda [1085] did not find any significant effect of Gingko/laser. However, the ginkgo infusion used was at a homeopathic level (D3 = 1:1000 dilution), according to Witt.
Partheniadis-Stumpf [1086] also failed to find any effect from the combined ginkgo (6 ml Tebonin) infusion and laser. However, the laser was applied at a distance of one cm above the mastoid. The non-contact mode reduces penetration considerably and the mastoid is not ideal for reaching the inner ear.
Plath [306] treated 40 tinnitus patients with 50 mg Ginkgo biloba. 20 patients received sham laser irradiation, 20 real laser. A HeNe laser with 12 mW output and a GaAs laser with 5 laser diodes each with 15 mW average power and output was used, irradiation procedure approximately the same as for Partheniadis-Stumpf. In this study, however, 50% of the patients reported a reduction of the tinnitus of more than 10 dB, as compared with 5% in the control group, in both self-assessment and audiometric findings.
A similar study has been performed by von Wedel [1087]. 155 patients were treated with Ginkgo infusion (5 ml Syxyl D3) and laser. The outcome was negative. No information about the type of laser, treatment technique or dosage is given, making evaluation impossible.
Shiomi [686] has investigated the effect of infrared laser applied directly into the meatus acousticus, 21 J, once a week for 10 weeks. The result of this non-controlled study is as follows: 26% of the patients reported improved duration, 58% reduced loudness and 55% reported a general reduc¬tion in annoyance.
The same author [687] has also examined the effect of light on the cochlea using guinea pigs. Direct laser irradiation was administered to the cochlea through the round window. The amplitude of CAP was reduced to 53-83% immediately after the onset of irradiation. The amplitude then returned to the original level. The results of this investigation suggest that laser therapy might lessen tinnitus by suppressing the abnormal excitation of the eighth nerve of the organ of Corti.
More or less the same parameters were used in a controlled study by Mirtz [1088] but in this case there was no significant effect.
Nakashima [1266] treated 68 ears in 68 patients with tinnitus. A 60 mW laser was applied for 6 minutes (21.6 J), once a week for 4 weeks in a double blind study. There was no significant difference between the two groups, which is not surprising considering the few sessions and the low energy applied. No differential diagnosis between somatosensory and other causes for tinnitus was performed.
Wilden [474, 1089] uses a different method with a considerably increased dose. A set consisting of one visible laser and three powerful GaAlAs lasers is used, covering a large area over and around the ear in the non-contact mode. Doses between 3,000 and 5,000 J are given each session. Laser is applied as a monotherapy. More than 800 patients have been treated with this concept and positive effects are reported even for vertigo. Recent injuries in “the disco generation” are more easily treated than long-term chronic conditions. In a separate study [1090] Wilden reports improvement of the hearing capacity of these patients, as evaluated by audiometry. An advantage of the Wilden method is that several muscles with a possible somatosensory background will be affected by the large area of irradiation used.
Tauber [1091] has performed an ex-vivo laser penetration study. Based on these findings it was possible to calculate the energy needed to obtain a dose of 4 J/cm2 in the cochlea itself. Irradiation via the mastoid showed values 103 to 105 times smaller (depending on wavelength) than irradiation through the tympanic membrane. 30 patients were treated five times within 2 weeks [1092]. One group was irradiated with 635 nm diode laser, the other with 830 nm diode laser. By self-assessment around 40% of the patients reported a slight to significant attenuation of the tinnitus loudness of the irradiated ear.
Prochazka [1093] has evaluated the effect of combined Egb 761 Ginkgo infusion and laser in a blind study. 37 patients were divided into three groups. One group had Egb 761 only, one Egb761 and placebo laser, one Egb761 and real laser, 830 nm. The results in the three groups were as follows: no effect 29/26/19, less than 50% relief 44/48/29, more than 50% relief 18/26/36, no more tinnitus 9/0/26. Irradiation was performed over the mastoid and over the meatus acousticus, twice a week, 8-10 sessions, total 175 J.
In an extended study over 3 years Prochazka [1263] evaluated the effect of laser in a group of 200 patients. These patients were taking gingko biloba preparations (73%) or Betahistadine (39%) and also had physical therapy, mainly directed at the neck vertebrae. Laser therapy was performed with a 300 mW GaAlAs laser, 75 J/cm2 into the ear and 135 J/cm2 behind the ear. The outcome was: no more tinnitus 26%, more than 50% relief 43%, less than 50% relief 15%, no effect 16%. In addition a group of 31 patients were selected for a double blind study where the same therapy as above was performed, but one group received placebo laser. At 6 months the outcome was as follows, with laser/no laser: no more tinnitus 25.8%/0.0%, more than 50% relief 35.5%/25.8%, less than 50% relief 19.4%/48.4%, no effect 19.4%/25.8%.
Hahn [1310] examined 120 patients with an average duration of tinnitus of 10 years. The patients underwent pure-tone audiometry, speech audiometry and objective audiometry tests. The intensity and frequency of tinnitus was also determined. EGb 761 was administered 3 weeks before the start of laser therapy. The patients underwent 10 sessions of laser therapy, each lasting 10 minutes. An improvement in tinnitus was audiometrically confirmed in 50.8% of the patients; 10 dB in 18, 20 dB in 22, 30 dB in 10, 40 dB in 6 and 50 dB in 5 patients.
Rogowski [1094] divided a group of 32 tinnitus patients into one group receiving laser therapy and one receiving a placebo procedure. Dose, wavelength and treatment technique are not stated in the available English abstract. The effect was evaluated through VAS. Within the patient group, transiently evoked otoacoustic emissions (TEOAE) were measured before, during and after therapy. No significant difference between laser and placebo was found in annoyance or loudness of the tinnitus and in changes of TEOAE amplitude. These results indicate that there is no relationship between the effect of low-power laser and changes in cochlear micromechanics.

All the above studies assume that tinnitus and vertigo are always inner ear problems. However, these conditions frequently have a muscular origin (“somatosensory tinnitus”).
The percentage of patients with a muscular origin for their tinnitus/ vertigo is not known but seems to be large. A differential diagnosis is therefore very important before any therapy is applied, laser or traditional thera¬pies. If this is not done, studies of the effect of transmeatal laser therapy become a gamble. The outcome would rather be related to the type of tinnitus dominating in the verum group than the actual effect of the therapy. An interdisciplinary co-operation between the ENT physician and a dentist is recommended.
Meniere´s disease is a condition first described by the French physician Ménière in 1861. It is a clinical entity consisting of vertigo, fluctuating hearing loss and tinnitus. Few medical conditions have been so thoroughly studied and described, yet lacking an effective therapy. Tinnitus, however, is not necessarily associated with Meniere; it is often an isolated condition. But the treatment of somatosensory Meniere and somatosensory tinnitus is very similar and in the following we make a simplification and speak only about "tinnitus".
Muscular tension is a key element in somatosensory tinnitus. The role of the laser is to create an immediate reduction of pain in the muscle with a consecutive relaxation. Thus, this intervention will make all the following therapy faster and more successful. Somatosensory tinnitus has been difficult to treat and often passes without a diagnosis. The combination of laser ther¬apy in the traditional therapy of temporomandibular disorders and cervical spine disorders (CSD) has been proven to be a more successful way of helping these patients, compared to traditional therapies. However, it is not to be expected that all symptoms will subdue rapidly. The skill of the dentist, the co-operation of the patient and concomitant physiotherapy are important factors. Many patients will not be completely relieved of symp¬toms but the majority will experience a great reduction of their problems. According to Bjorne [1263] and Estola-Partanen [1267] the treatment of somatosensory tinnitus reduces the severity of tinnitus more than the inci¬dence. The 3-year follow up study by Bjorne [1263] showed simultaneous decreases in the intensities of vertigo, nonwhirling dizziness, tinnitus, feeling of fullness in the ear, pain in the face and jaws, pain in the neck and shoul¬ders, and headache that were both longitudinal and highly significant. Signif¬icant reductions in the frequency of vertigo, nonwhirling dizziness, and headache were also reported by the patients as well as complete disappear¬ance of pain located in the vertex area. A significant relief of TMD symptoms and decrease in nervousness was also achieved. It must be underlined that the success in the study [1263] reflects the outcome of the therapy before the author started to use laser therapy as an additional method. The addition of laser therapy has then further improved the progress in this category of patients. Frequently these patients can notice a change in the character of their tinnitus when the lateral pterygoid muscle is irradiated.
The suboccipital muscles should also be palpated, since these muscles and the masticatory muscles are closely functionally connected. In fact, the mandible and the upper cervical joint (C0/C1) constitute an integrated motor system.
The therapy outlined below brings new hope to a large group of "intractable" patients. It outlines the traditional therapy created by Bjorne, with the recent (2000) successful addition of laser therapy.

Somatosensory tinnitus examination and therapy acc. to Bjorne/Tunér
Anamnesis
Does the patient experience a feeling of fatigue in the jaws, difficulties in mouth opening, sensations of tension in the jaws/neck, hypersensitive or tender teeth, clenching of tongue/jaws, tendency for general stress, wakes up at night due to tinnitus?
Can the patient manipulate his/her tinnitus through movements of the jaw and neck? Usual movements evoking this phenomenon are: opening the mouth wide, protrusion and side movements of the mandible, flexion/ extension and side rotation of the upper cervical joints.
Can the patient manipulate his/her tinnitus by putting pressure/ stimulation in the areas of the sensory innvervation of the trigeminal nerve of the trigeminal nerve? Usual areas evoking this phenomenon are putting pressure on tragus, over the cheek, jaw or temple, the stylomandibular ligament but also gazing with the eyes.
Are there other symptoms related to tension: pain in the jaws, face, neck, and headache?

Status
Observation of hypertrophic masticatory muscles and possible abnormal posture of the head/neck.
Palpation of the masticatory muscles (the lateral pterygoid muscle in particular), the TMJ, and the suboccipital muscles.
Range of movement of the mandible and neck.
Active shining bruxing facets as signs of active bruxism.

Therapy
Laser treatment of tender areas in the jaw and neck muscles, 5-15 J per point depending on size and location of muscle. 2-3 sessions per week acc. to the evolution of improvement, preferably with GaAlAs or GaAs laser.
Training in how to normalise abnormal head/neck posture, and training how to relax masticatory, neck and shoulder muscles.
Training of autostretching of the suboccipital muscles (the rectus capitis posterior minor and major muscles and the obliquus capitis superior muscles), the upper and middle trapezius muscles and the levator scapulae muscles. Laser therapy of tender areas in these muscles is also recommended.
Minute examination of occlusal function and presence of active interferences, followed by adjustment through grinding.
Information about the necessity of adjusting style of life.
Bite splint in selected cases

Most common dental occlusal backgrounds:
The patient is clenching/bruxing on active shining facets of the front teeth, forcing the TMJ:s to slide forwards, due to activation/tension of the lateral pterygoid muscles.
Cross bite (sliding areas preventing central occlusion and balanced TMJ position).
Elongated teeth, forcing the TMJ into an unbalanced position.

Also see old article Low level laser therapy of tinnitus - a case for the dentist?