CleveMed Blogs

While most people know what tremor is when they see it, they may not realize that many different types of tremor exist and why it is important to recognize them. The current gold standard of visual assessment may be blind to subtle characteristics unique to different tremor types. Tremor is a common motor symptom associated with a number of neurological disorders. Defined as rhythmic, involuntary, to-and-fro movements of a body part, tremor is most common in the hands, but can occur in the arms, legs and head. Tremor can be an especially debilitating movement disorder symptom and make activities of daily living, such as dressing, eating and writing, difficult or sometimes impossible without the help of a family member of caretaker.

Several movement disorders produce tremor as a motor symptom. The two most common are essential tremor (ET) and Parkinson’s disease (PD). ET is a common disorder characterized by uncontrolled trembling of the hands and often involuntary nodding of the head. It is the most prevalent movement disorder, affecting nearly 10 million people in the United States alone. PD is a progressive disease associated with the destruction of brain cells that produce dopamine and characterized by muscular tremor, slowing of movement, partial facial paralysis and peculiarity of gait and posture. There are currently about 1 million people in the United States living with PD.

In addition to different disorders producing tremor, different tremor types may exist within a particular disorder, each with unique physical characteristics. Two of these important characteristics are amplitude and frequency. Amplitude refers to how big the movement is while frequency refers to the speed or rate at which the oscillation is happening. Rest tremor is one type that occurs when the affected limb is completely at rest. Resting tremors occur at a specific frequency, usually 4 – 7 Hz, and are most commonly associated with PD, but in some cases found in other movement disorders. Postural tremor occurs when a specific body part is held motionless against gravity, such as extending the arms out, pointing with the hands or sitting upright without back support. Postural tremor typically occurs at a frequency of 9 – 11 Hz and can be associated with PD or ET. Other types of tremor include kinetic tremor, which occurs during a voluntary movement such as writing, drinking or eating and intention tremor, which is unique in that is occurs during a visually guided movement toward a target destination.

Distinguishing tremor types and quantitative features is very important for research, clinical judgments and intervention efficacy. CleveMed has developed a device called Kinesia™ that can be used to detect and monitor subtle differences in tremor characteristics. Kinesia is a small wireless device worn on the patient’s finger and wrist to monitor three dimensional motion. Currently being evaluated in several clinical studies around the United States, this device is intended to help standardize tremor evaluations and provide clinicians with a tool to better quantify tremor features when the signs are too subtle for clinical differentiation alone. Improving and standardizing the clinical evaluation of tremor may ultimately improve the understanding of tremor subtypes, increase efficacy of interventions and maximize patient quality of life.