Essential Tremor, Cognitive Impairment, and Self Awareness

Numerous movies have been made that sensitively deal with the issue of failing cognitive function and its impact both on the patient and the person(s) who love him or her. In almost all of them, the condition that drives the emotions and actions of the players is Alzheimer’s disease. As we know, Alzheimer’s is a serious incurable illness, and the degree of cognitive impairment (loss of memory, judgment, and executive planning/decision-making functions) is severe and irreversible.

I’m writing about a much less severe form of mental deterioration that some studies have linked with Essential Tremor (ET) in aging patients. It is called clinically significant cognitive impairment (SCI), and this distinguishes it from mild cognitive impairment (MCI) that is a common effect of aging as people live longer and longer.

A matter of degree

Cognitive impairment is complicated and often progressive, making it difficult to define. Having MCI like. forgetting where one’s glasses are, or momentary confusion about whether it’s Monday or Tuesday, creates inconvenience. However, it doesn’t much reduce daily function or general quality of life. On the other hand, as mental function diminishes, it can be a challenge to organize one’s day, accomplish tasks, and make good judgments about personal safety. Thus, SCI is a greater degree of impairment than MCI, and requires more frequent evaluations and more intensive caretaking or supervision.

Signs of clinically significant cognitive impairment include:

  • Confusion
  • Poor motor coordination
  • Loss of short-term or long-term memory
  • Identity confusion
  • Impaired judgment

No consensus on ET and cognitive impairment

Not every researcher is convinced that progressive mental decline or dementia is linked with ET in older patients. While the majority of evidence supports the opinion that late onset ET brings increased risk for dementia, Shill et al. (2014)1 found no connection. (See my blog on this debate.) Whether or not there’s a pattern, I found myself wondering if ET patients who begin to experience cognitive decline know that it’s happening, as some of the characters in the Alzheimer’s movies do for fleeting moments.

Certainly, changes in cognitive function would be apparent to concerned loved ones and caregivers, and it adds to the caregiving burden even with MCI, let alone SCI. This has been demonstrated in Parkinson’s disease (PD) where cognitive dysfunction is virtually inevitable: “Patients who present with mild cognitive impairment (PD-MCI) are at high risk of progression [to dementia]…It is well-established that there is higher caregiver burden and reduced quality of life in caregivers once dementia onset has commenced in PD.”2 In many cases, PD patients are aware of having to struggle with growing mental dysfunction. In one study of PD patients who develop poor impulse control, possibly due to diminishing executive function in many instances, the patients were indeed aware that they were unable to resist impulse-motivated behaviors.3

ET patients with CSI – do they recognize what’s happening?

What about persons with ET? Azar et al. (2017) write, “The extent to which individuals with ET who have clinically significant cognitive impairment are aware of their cognitive changes is unclear.”4 One way to find out is to have patients and caregivers complete questionnaires, and compare results; are patient self-perceptions in line with caregiver perceptions? Another method is that used by the Azar research team. They enrolled 150 persons with ET (109 were assessed to have normal cognitive function, 30 had MCI and 11 had dementia or SCI). All participants were given objective assessments of memory, language and executive functioning, as well as recording how they rated themselves in each area. In this approach, self-ratings were compared with objective evaluations, and those with normal cognitive function were compared with MCI/dementia individuals.

The authors found that those with normal cognitive function accurately self-assessed their level of function. However, “Individuals with ET and cognitive impairment overestimated their performance in all domains of functioning.” Having concern that individuals with both ET and cognitive impairment may not be accurately self-aware of their condition, the authors recommend proactive and regular screening in their cognitive function.

Self-awareness: a challenge

As with a multitude of medical and psychological conditions, there are online peer support discussion forums. Those who are self-aware write eloquently about their increasing challenges and even impending diminishment of selfhood – which must seem like some kind of Shakespearean curse – but many others respond that they find hope and solace from these self-revelations. They know that they are not alone, which is a blessing.

Persons with ET frequently feel isolated and misunderstood. Perhaps they, too, could take comfort from reading such forums, even if they don’t wish to contribute. The cruel irony of cognitive decline is the possibility of not recognizing it as it’s happening. But finding an online support community may help someone achieve the peace resulting from Shakespearean wisdom: “To thine own self be true.”

1Shill HA, Hentz JG, Jacobson SA, Belden C et al. Essential tremor in the elderly and risk for dementia. J Neurodegener Dis. 2014;2014:328765.
2Jones A, Kuijer R, Livingston L, Myall D et al. Caregiver burden is increased in Parkinson’s disease with mild cognitive impairment (PD-MCI). Transl Neurodegener. 2017; 6: 17.
3Mack J, Okai D, Brown RG, Askey-Jones S et al. The role of self-awareness and cognitive dysfunction in Parkinson’s disease with and without impulse-control disorder. J Neuropsychiatry Clin Neurosci. 2013 Spring;25(2):141-9.
4Azar M, Bertrand E, Louis ED, Huey E et al. Awareness of cognitive impairment in individuals with essential tremor. J Neurol Sci. 2017 Jun 15;377:155-160

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.

An update on COVID-19: Your health and safety are our top priority.
 Learn More