Whitney M. Sommerville, Au.D.• Last updated on: January 30, 2019
You may be interested in our multiple other pages on tinnitus.
The Chiari malformation, specifically type I, is a syndrome in which the cerebellar tonsils that are located on the underside of the cerebellum are downwardly displaced below the foramen magnum at the base of the skull. Chiari malformation type I is thought to occur in utero, however symptoms may not occur until middle age or may not occur at all. One possible symptom of Chiari malformation is tinnitus.
Tinnitus is the subjective experience of hearing sound, most commonly ringing, when there is no outside source creating the sound. The following will discuss associations between the Chiari malformation and tinnitus.
Tinnitus is usually caused by ear damage, while the Chiari malformation generally does not affect the ear. One would expect then that there would be the same general frequency of tinnitus in patients with Chiari as persons in the general population (i.e. about 20%, see below). Nevertheless, there is some suggestion that tinnitus is especially common in Chiari. Milhorat and associates reported that out of 354 patients with Chiari malformation 38% reported tinnitus(Milhorat et al., 1999). In another study, Mueller and Oro reported on a Chiari patient symptom questionnaire that 56% of the participants noted tinnitus as a symptom(Mueller & Oro, 2013). In a case report, one 49 year old individual did not know about her Chiari condition until seeking medical advice for tinnitus that had been persisting for 3 months without other audiologic findings, such as hearing loss (Pruszewicz, Wojnowski, & Jackowska, 2007). Tinnitus has also been reported in association with increased cerebrospinal fluid pressure, which occasionally is associated with Chiari (Wiggs, Sismanis, & Laine, 1996). Although these studies suggest that there may be more tinnitus in persons with Chiari, given the lack of extensive data about Chiari and Tinnitus and the lack of a reasonable mechanism for an association, we think that whether or not Chiari is a risk factor for tinnitus is not yet settled.
Looking at thing from the other side, if you have tinnitus, how likely is it that you have the Chiari malformation ? Although tinnitus can be associated with Chiari malformation, tinnitus in general is hugely more common than the Chiari malformation. About 10-30% of the entire population has constant tinnitus (Adjamian, Sereda, & Hall, 2009) (McCormack, Edmondson-Jones, Somerset, & Hall, 2016) (Park & Moon, 2014). Thus, as roughly 20% of the population has tinnitus, and nowhere near 20% of the population has Chiari, the odds are very low that a person who has tinnitus also has a Chiari. Furthermore, if you have tinnitus and Chiari both, the chances are very high that your tinnitus is from something other than the Chiari malformation. The American Tinnitus Association lists hearing loss, temporomandibular joint disorders, head and neck trauma, traumatic brain injury, and ototoxic drugs (such as aspirin) as causes for tinnitus.
In conclusion, if you are experiencing tinnitus with Chiari malformation it may be due to the condition, but that should not be assumed. If you already know you have a Chiari malformation, a health care professional such as an audiologist or a physician who has expertise in tinnitus may be helpful in sorting out whether the Chiari malformation, or another condition, such as hearing loss, is contributing to or causing the tinnitus.
Acknowledgements: This page was posted by and reviewed by Dr. Timothy Hain.