Cranial tremors, including head, voice, and jaw tremors, can occur in patients with essential tremor (ET), often becoming more prevalent with longer disease duration.1 Jaw tremor has been estimated to occur in 7.5–18.0% of ET patients, with prevalence related to the method of case ascertainment.2 The tremor more often occurs when the mouth is open (e.g., during speech) rather than closed. While the tremor may range from mild to severe, it is rare for jaw tremor to represent anything other than a cosmetic concern. We are unaware of any documented cases of jaw tremor producing bodily injury. We now report an 86-year-old female diagnosed with ET in her early 70s; her symptoms had begun at age 71. In August 2015, she was enrolled and consented to be a participant in a clinical research study approved by the Yale University Ethics Committee. At that time, she reported no family history of ET. By history, the tremor involved her arms, head, jaw, and voice, with marked jaw tremor being a major issue. On examination, there was mild postural tremor and moderate-to-severe kinetic tremor of both arms, with head and voice tremors. There was also a prominent jaw tremor. Additional history was as follows: by 2014, her jaw tremor had become so severe that she described her teeth as clicking continuously, at times forcefully striking against one another. The first catastrophic event occurred in September 2014. Her jaw movements had become severe and she broke her first right upper bicuspid tooth; a crown was introduced as a result of this. A second episode occurred soon after when she broke that crown and her adjacent canine tooth, for which she required a bridge. After that episode, she was placed on primidone, eventually reaching a dose of 250 mg/day, with a consequent marked (>50%) reduction in jaw tremor (Video 1). Such severe jaw tremor is a rare occurrence in patients with ET. Nevertheless, it behooves clinicians to be aware of the full spectrum of this disorder and of the potential consequences of cranial tremors in ET patients.
Video 1
Tremor of the Jaw Is Evident during Speech and Sustained Phonation. The patient is treated with primidone 250 mg/day, which has resulted in a substantial (i.e., 50%) reduction in her jaw tremor.
Notes
[1] Supported by Funding: Dr. Louis has received research support from the National Institutes of Health: NINDS R01 NS042859 (principal investigator), NINDS R01 NS39422 (principal investigator), NINDS R01 NS086736 (principal investigator), NINDS R01 NS073872 (principal investigator), NINDS R01 NS085136 (principal investigator) and NINDS R01 NS088257 (principal investigator).
[2] Financial disclosure Financial Disclosures: None.
[3] Conflicts of interest Conflict of Interest: The authors report no conflict of interest.
[4] Conflicts of interest Ethics Statement: All patients that appear on video have provided written informed consent; authorization for the videotaping and for publication of the videotape was provided.