A while back we received a great question from Joyce Wasserman, PT, PRC on Tinnitus.  Read her question and Ron Hruska’s response…

“I am looking for references that link tinnitus to suboptimal dental occlusion or absence of centric occlusion. I’d appreciate any leads, names of journals or websites, that I should be looking at. Has any of the PRC therapists been able to help people with tinnitus, alone or in collaboration with a dentist?”

Tinnitus, or ringing in the ears, can be a very confusing and often poorly understood symptom.  Tinnitus and dizziness are the two most frequently asked about symptoms, both here in the clinic and through the internet.  From the reading that I have done, it is thought to occur when the brain areas involved in hearing spontaneously increase their activity.  Therefore, it is associated with virtually all disorders of the auditory system.  It is not limited to ringing of the ears, but may be perceived as whistling, buzzing, humming, hissing, roaring, chirping or other related sounds. 

There appears to be three forms of tinnitus.  The last is more of an osteopathic thought process approach.  Nonetheless, I’d like to cover all three briefly in this response to a question received by a PRC therapist about the relationship between tinnitus and dental occlusion.  The first most common form of tinnitus according to James B. Snow Jr., a physician at the University of Pennsylvania, and former director of the National Institute on Deafness and other communication disorders, arises from damage to the inner ear, or cochlea, caused by exposure to high volumes of sound.  Dr. Snow also states that drugs such as aspirin, quinine and aminoglycoside antibiotics, cancer chemotherapeutics and other ototoxic agents, and infections and head injuries.  He goes on to state that if the inner ear is damaged, input decreases from the cochlea to the auditory centers of the brainstem, such as the dorso cochlear nucleus.  This input loss may lead to increased spontaneous activity in the nucleus neurons as a result of inhibition that has spontaneously been removed. 

The second most common form or theory of tinnitus is autonomic nervous system stimulation from increased neuromuscular tension.  Retraining therapy, a process that can take a long time, often two years or more, can help reduce this tension from the autonomic nervous system.  This process is called habituation of reaction.  Tinnitus then becomes quieter for longer periods of time and eventually or hopefully will disappear or become a natural part of the background noise or “sound of silence”.  This is sometimes referred to as habituation of perception.  This won’t happen if or while the tinnitus is still classified by the person experiencing it as a threat, negative experience, an undiagnosed symptom, or while the individual is under a lot of emotional stress.  Many tinnitus patients have hyperacousis or high degrees of sensitivity to external noise and therefore they seek and search for quiet environments to work in.  In this respect, according to information from http://www.tinnitus.org, they are their own worst enemy.  Supposedly, if strong beliefs about the threatening nature of tinnitus are maintained, the survival style or condition response mechanisms in the subconscious brain insure that it is continuously monitored and therefore the condition itself will not improve.  Imaging studies confirm increased neural activity in the auditory cortices of those experiencing tinnitus.  Their brains also show increased activity in the limbic structures associated with emotional processing.  Other symptoms that sometimes appear alongside tinnitus, such as emotional distress, depression, dizziness, and insomnia, may have a common basis in some limbic structure such as a nucleus accumbens. 

In addition to the two most common forms of Tinnitus, that is damage to the inner ear and increased tension from the autonomic nervous system stimulation, I find that there is a very strong relationship between tinnitus and those who are experiencing temporal bone disorganization or temporalis overuse.  Clenchers, grinders, and trismus oriented individuals often experience tinnitus associated with hyperactivity of musculature that is attached directly to the temporal bone which houses the inner ear.  There does not appear to be a relationship between tinnitus and externally or internally rotated temporal bones at this time according to the literature, however, it does stand to reason that this third reason for tinnitus is strongly related to the position and orientation of a muscle called the tensor tympani muscle that inserts on the manubrium of the malleus bone and originates or attaches directly to the sphenoid bone and the temporal bone.  It lies in our auditory tube and its main action is to tense the tympanic membrane along with the stapedius muscle of the ear.  It also contains cerebellar input related to the ability to adapt to vision as well as hearing.  Since this muscle makes the tympanic membrane taught if it is put in a position where it is lengthened it can also influence its own innervation by the mandibular division of the trigeminal nerve.  It can have a direct impact on the external surface of the tympanic membrane. 

The external surface of the tympanic membrane is innervated by the oriculo temporal branch of the mandibular nerve and the oricular branch of the vagus nerve.  The internal surface of the membrane is supplied by the tympanic branch of the glossopharyngeal nerve.  Temporal and sphenoid orientation, therefore, can have a both direct and indirect impact on the autonomic nervous system, trigeminal innervation, and vagal activity.  Clinically, keeping the temporal innominates aligned, stable, and functioning in a reciprocal manner with respiration and mandibular activity is important to keep the tympanic membrane, tympanic cavity, and septum of the auditory muscular canal aligned.  Through manual or non-manual techniques using PRI principles and philosophy, I have been able to change the frequency and intensity of this irritant.  Many of these same patients also need to be evaluated by a dentist with a strong background in TMD and occlusion and it’s always helpful to work with a dentist who has a cranial-gnathic orthopedic mind.  Being familiar with the different lesions of the cranium that can occur with malocclusion is always helpful in restoring proper cranial symmetry with a bite. 

In addition to this I’ve also had success in working with optometrists, specifically COVD trained optometrists, who presently understands the autonomic nervous systems influence on accommodation and tension across the cranium as a result of vestibular constraint secondary to visual and spatial lack of integration.  Hopefully, this overview will help anyone working with a patient experiencing tinnitus.  Obviously, we’re excited that the physical and physiological implications associated with tinnitus, can be corrected or reduced using methodology that diminishes the asymmetrical issues at the temporal region as well as the hypersensitivity associated with torque placed on the temporal bone itself.