Essential Tremor: You or a Relative Might be Mistaken

You make an appointment to see your primary care doctor, or perhaps your neurologist. The doctor asks, “So what brings you here?” Your answer is what is called a self report. This means you provide details about the condition that led you to request an appointment to begin with. Doctors rely heavily on their patients’ self-reported descriptions, but are unlikely to make an immediate diagnosis based on them. Instead, the doctor will ask questions to get a better understanding of what you’re saying, to go more deeply into your self-report, and to start ruling out things that also fit the description.

Self reports about ET: How reliable are they?

A recent study in the Journal of Neurological Studies got my attention, since it had to do with inaccurate essential tremor (ET) reports made by persons with ET about family members. In other words, this was a type of genetic study, because ET often runs in families. An important term in the study is proband, which usually means the first family member to seek medical attention for a genetic disorder. There may be other ancestors or relatives with the disorder; some may already be identified, but sometimes others are unknown “due to the lack of information regarding those individuals or about the disease at the time they lived.”i In any case, diagnosing a person with a possibly hereditary condition raises suspicion that others in the family – living or dead – also have it.

The purpose of the study was to explore the reliability of probands’ self-reports and reports about relatives. The authors write,

The search for genes for essential tremor (ET) is active. Researchers often depend on probands’ reports or self-reports to assign disease status to relatives. Yet there are surprisingly few data on the validity of these reports.ii

The authors enrolled 98 people diagnosed with ET, and 243 relatives. All participants were first screened for tremor, and then had a videotaped in-person neurological evaluation. One of the study investigators then evaluated the screening questionnaires and videotapes, and assigned a diagnosis of either ET, borderline tremor (BT), or other diagnosis. 105 participants were diagnosed with ET and 34 with BT.

Nearly 30% misidentified themselves or relatives

While the majority of the reports matched the study diagnoses, there were inaccuracies:

  • Probands failed to report 39 out of 139 relatives diagnosed with ET or BT
  • Probands reported tremor in 32 out of 104 relatives who were not diagnosed with ET or BT
  • Out of the 139 relatives diagnosed with ET or BT, 36 failed to self-report tremor
  • Out of the 104 relatives diagnosed with ET or BT, 30 self-reported that they had tremor

After statistical calculations, the authors found that probands were mistaken about 29.2% of their relatives, and 27.2% of the relatives were mistaken about themselves. This means that there was nearly a 30% misidentification rate in reporting relatives, and a 27% inaccuracy rate in the relatives’ self-reports.

If you have ET and you are aware of (or suspect) the presence of tremors in ancestors or living relatives, what is your experience of how tremor is identified in your family? How many of your relatives with tremors have sought medical help? There is much current thinking that ET is more prevalent than even the highest estimates.

It’s easy for family members to over-identify or under-identify tremors depending on which part of the body is affected, especially if they are early and not very evident. Also, some families have a stronger norm of openness about such matters, while other families have greater privacy or “we don’t talk about such things” norms.

If you or a loved one are concerned about the presence of ET, it’s important to get a professional evaluation—and a second opinion. Even doctors and movement disorder specialists run up against diagnostic challenges, since many conditions can lead to tremors. In particular, ET can be misdiagnosed as Parkinson’s disease.

Millions of people have ET and are able to manage well, with or without medication. However, drugs are effective for only about half of those with ET. For more information on a new noninvasive treatment to control ET safely and effectively without medication, contact Sperling Neurosurgery Associates.

ihttps://en.wikipedia.org/wiki/Proband

ii Louis ED, Hernandez N, Sebastian AA, Clark LN, Ottman R. Validity of probands’ reports and self-reports of essential tremor: Data from a large family study in North America. J Neurol Sci. 2018 Aug 6;393:45-50. doi: 10.1016/j.jns.2018.08.006. [Epub ahead of print]

 

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