Essential Facts about Essential Tremor

Dragnet was a police drama series that ran first on radio, then on TV. It featured Sergeant Joe Friday who occasionally found himself questioning witnesses, many of whom were female and tended to ramble. While Friday never exactly said, “Just the facts, ma’am,” as commonly attributed to him, it’s close enough to his actual words: “All we want are the facts, ma’am.”

Essential tremor facts

In the world of neurology, the branch of medicine that deals with the anatomy, functions and disorders of the brain, science constantly brings to light new facts. However, some things remain shrouded in as-yet impenetrable mysteries. For example, we do not yet know what causes essential tremor (ET), the most common movement disorder. Since we don’t know the cause, we have to find a cure.

However, there are many facts we do know about ET. Even if many of them do not directly contribute to discovering the cause or cure, they serve to spotlight the need for ongoing scientific research so that one day—hopefully soon—the puzzle pieces come together and we’ll know how to prevent or cure ET.

Many facts are already available to us. The following were reported by Zesiewicz, et al. (2010)[i]:

  • ET is more prevalent than Parkinson’s disease and Alzheimer’s disease
  • In addition to motor symptoms (tremors of hands, head, other parts of the body), ET is associated with cognitive and mood disorders
  • No world population is immune to ET
  • The incidence of ET increases with aging; about 4% of adults 40 years of age and older are affected by ET
  • Alcohol temporarily diminishes tremor amplitude in 50-90% of cases, although this may worsen after the effect has worn off
  • About 90% of patients have tremor in their upper extremities, 30% have head tremor, 20% have voice tremor, 10% have face or jaw tremor, and 10% may have a lower limb tremor.
  • It is estimated that ET is misdiagnosed in 30% to 50% of cases
  • Roughly half of ET patients have an affected first-degree relative, and first-degree relatives of ET patients also appear to be 5 times more likely to develop ET than control subjects
  • A family history of ET is associated with younger reported age of tremor onset (but this may be due to families seeking medical help early for affected children)
  • In addition to the above facts, the International Essential Tremor Foundation[ii] offers the following:

  • ET can occur at any age from childhood onward
  • There are few effective medications, and estimates suggest that less than 60% of people are helped by them
  • An estimated 10 million Americans have ET

Facts about Focused Ultrasound treatment

At the time the Zesiewicz paper was published, there were two neurosurgical procedures available for persons with ET whose tremors did not respond to medication. One, called thalamotomy, created a lesion in a tiny area of the brain’s thalamus called the VIM nucleus; typically, a probe is inserted into the side of the brain that controls the dominant hand, and the lesion is generated by an extreme freeze. Although tremor diminishment/control was reported at rates upwards of 80%, this procedure is rarely done today. The other, called Deep Brain Stimulation, involves the insertion of electrodes into a targeted area of the brain and a battery pack into the chest; when the electrodes are switched on, tremors are diminished/controlled.

There is a more recent treatment called MRI-guided Focused Ultrasound (MRgFUS or simply FUS) that is quickly gaining favor. Here are some facts about MRgFUS:

  • In July, 2016, the FDA approved the use of MRgFUS to treat ET
  • MRgFUS is a single outpatient procedure that creates the equivalent of a surgical thalamotomy
  • It is noninvasive (no cutting or drilling of holes through the skull to access the brain)
  • It is currently done to deaden the VIM nucleus only on the side that controls the dominant hand, but European clinical trials exist for treating both sides, or the other side at a later date
  • MRgFUS has promising long-term results. A study of 44 ET patients who had MRgFUS at a single center and were followed for up to 5 years reported that the majority of patients had lasting results, with only 5 reporting that the return of tremors impacted their daily lives.[iii]

Although science does not have all the facts about the origins of ET in the brain, it has contributed a safe and effective treatment for controlling tremors without drugs or brain implants. For those who have had the procedure, regaining their quality of life is something for which they are happy and grateful. And that’s a fact.

NOTE: This content is solely for purposes of information and does not substitute for diagnostic or medical advice. Talk to your doctor if you are experiencing pelvic pain, or have any other health concerns or questions of a personal medical nature.

[i] Zesiewicz TA, Chari A, Jahan I, Miller AM, Sullivan K. Overview of essential tremor. Neuropsychiatr Dis Treat. 2010; 6: 401–408.
[ii] https://www.essentialtremor.org/wp-content/uploads/2019/06/FactSheet062019.pdf
[iii] Sinai A, Nassar M, Eran A, Constantinescu M1 et al. Magnetic resonance-guided focused ultrasound thalamotomy for essential tremor: a 5-year single-center experience. J Neurosurg. 2019 Jul 5:1-8.

 

About Dr. Dan Sperling

Dan Sperling, MD, DABR, is a board certified radiologist who is globally recognized as a leader in multiparametric MRI for the detection and diagnosis of a range of disease conditions. As Medical Director of the Sperling Prostate Center, Sperling Medical Group and Sperling Neurosurgery Associates, he and his team are on the leading edge of significant change in medical practice. He is the co-author of the new patient book Redefining Prostate Cancer, and is a contributing author on over 25 published studies. For more information, contact the Sperling Neurosurgery Associates.

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