What’s the Difference between “Progressive” and “Degenerative”?

Essential tremor (ET) is often mistaken for Parkinson’s disease (PD). Each of these conditions tends to first appear among older adults (age 40+ for ET, age 60+ for PD). In both conditions, the first telltale sign is generally uncontrollable tremor or shaking of the hands. However, there are some important differences between the two. ET is accompanied by a family history in about half of cases, whereas this is rarely true for PD. ET tremor is often absent when the hands are at rest, but PD tremor is observed even when the hands are resting. Perhaps the most important difference is that ET is a progressive condition, while PD is a degenerative disease.

ET is progressive

ET is not a life-threatening disease. It generally affects the hands, though the arms, head and voice can also develop tremors. ET can stay mild for many years, but most people with ET have some degree of worsening over a period of years. This is why it is called progressive.

Defining stages of tremor progression is challenging because ET may not behave similarly from one person to another. For this reason, many researchers now believe ET is a family of conditions. However, a simple 4-stage scale was devised by a Spanish research team to help them track the rate of ET progression in various age groups. Persons whose ET began in childhood do not seem to progress as quickly as those whose onset started after age 60.

It’s important to note that ET very rarely progresses to the point where the whole body is involved. This is quite different from PD.

PD is degenerative

A diagnosis of PD is very discouraging because it means that the brain is degenerating irreversibly as brain cells die off. While PD it is also progressive (symptoms worsen), the course of PD inevitably leads to nearly total impairment, including mental and cognitive function as well as physical breakdown affecting most bodily systems.

Tremor treatments

The first line of treatment for both ET and PD is the use of medications to control tremors. If, however, medication is not initially effective, or loses effectiveness, and/or side effects become unacceptable, a new noninvasive treatment called MRI-guided Focused Ultrasound (MRgFUS) is highly successful for controlling ET. (It is also in clinical trials for PD-related tremors.)

MRgFUS

MRgFUS uses image-guided beams of ultrasonic energy that can penetrate the skull and brain to stop tremors at their source. In the case of ET, abnormal brain messages that originate in the cerebellum are “relayed” to the hands and other body parts by the VIM nucleus of the thalamus located deep in the brain. Under MRI guidance, ultrasound beams are aimed from hundreds of different directions at the VIM nucleus. When all the beams simultaneously meet, they ablate (destroy) the VIM nucleus so it can no longer forward the error messages – yet this does not affect other normal brain functions.

Patients whose ET has been stopped by MRgFUS are very happy. There are no incisions or holes drilled in their skull, and they quickly return to normal activities with minimal to no temporary side effects.

Sperling Neurology Associates offers Neuravive MRgFUS for qualified patients. For more information, contact us through our website.