TREMOR
Definition
"A rhythmical oscillation of a body part "
6 Main Types: (More detailed information can be found below)
- Physiologic
- Essential / Familial Basal Ganglia (Parkinsonian) Cerebellar Dystonic
- Others
Physiologic Tremor(frequency 10-12 Hz)
This is a common tremor. Almost everyone has experienced this tremor. There is likely a lowered threshold for this type of tremor in certain families. It is seen when it is triggered by
anxiety, fever, hyperthyroidism, physical exhaustion, low blood sugar. Some medications and some chemicals (e.g. theophyline, caffeine, alchohol withdrawl) will accentuate physiologic tremor. Treatment:
Often no treatment is necessary other than reassurance once the diagnosis is made. Triggering factors should be removed (eg. reduce caffeine intake). If severe enough
medications, including B-blockers or anxiolytics, can be prescribed.
Essential Tremor
(frequency 4-12 Hz) This is the most common movement disorder. It is an inherited condition and the trait to
this tremor can be passed from generation to generation. Fifty percent of children of an affected parent will inherit the tendancy to get the tremor (autosomal dominant inheritance).
The tremor often starts on one side but usually will affect both sides within 2-3 years of onset. The tremor severity slowly worsens with age (frequency slows, amplitude increases)
with some stable phases occasionally lasting years. The tremor may be very disabling with 15% of patients having to retire prematurely.
The tremor may affect hands, arms, legs (~30%), voice, and/or head. This tremor typically stops with It is worse when it is triggered by anxiety, fever, hyperthyroidism, physical exhaustion or low blood sugar. Some medications and some chemicals (e.g. theophyline, caffeine, alchohol
withdrawl) will accentuate essential tremor. Treatment: Often no treatment is necessary other than reassurance once the diagnosis is made. Some
councilling may be required in younger patients regarding career choices. Triggering factors should be removed (eg. reduce caffeine intake). If severe enough medications can be prescribed. Medication options:
1) Propranolol on an as needed basis, such as prior to stressful events (works within a half hour and usually lasts 2-3hrs). 2) Chronic use of Propranolol (doses > 120 mgs/day).
3) Chronic use of primidone. 4) Propranolol and Primidone combined 5) Topiramate (Topamax) up to 100 mgs bid 6) If the above are ineffective diamox, neptazane (methazolamide), clonidine, amantidine,
clonazepam, neurontin, clozapine have been suggested as other options. 1) Steriotactic radiofrequency thalmotomy is a procedure that surgically destroys the very small area deep within the brain that causes the tremor (the thalamus). This, if successful,
will stop the tremor on the opposite side of the body. There are, as with any surgery, possible side effects that need to be discussed and considered.
2) Gamma knife (radiosurgery) thalmotomy is also a procedure that destroys a very localized area in the brain by applying many small radiation beams into one focussed spot. This
procedure can be done without the need of any incisions. It also doesn't take as long to complete. The experience with this technique is limited, athough it is developing as a option
for those patients unable to tolerate the more prolonged procedure.
3) Another option is to implant a deep brain stimulator (a small electrode implanted into
thalamus that is connected to a programmable transmitter under the chest wall, like a pacemaker). By electrically interfering with the natural firing pattern of the nerve cells in this
area the tremor is electrically suppressed. This, if successful, will stop the tremor on the opposite side of the body. There are, as with any surgery, possible side effects that need to be discussed and considered.
Basal Ganglia Tremor (Parkinsonism) (frequency 4-5 Hz) This is the type of tremor seen as part of the features of Parkinson's Disease and other
illnesses damaging the basal ganglia. The basal ganglia is a group of nerve cells (ganglia) deep within the brain (at the base of the brain). It is most evident at rest and unlike essential
tremor tends to improve with posturing or action. Approximately 30% of patients with Parkinson's Disease can have an associated action tremor (6-12 Hz). These tremors start on
one side and will usually progress to the other side. Treatment: Medication options: The medications typically used to treat Parkinson's Disease often suppress tremor quite
successfully. Despite this some patients will suffer from medically unresponsive (refractory) tremor. The main medications used include; levodopa, dopamine agonists, amantadine, and anticholinergics.
When this type of tremor occurs as the result of other diseases which affect the basal ganglia (eg. stroke) it is less responsive to medication. 1) Steriotactic thalmotomy is a procedure that surgically destroys the very small area deep
within the brain that causes the tremor (the thalamus). This, if successful, will stop the tremor on the opposite side of the body. There are, as with any surgery, possible side effects
that need to be discussed and considered. 2) Gamma knife (radiosurgery) thalmotomy is also a procedure that destroys a very localized area in the brain by applying many small radiation beams into one focussed spot. This
procedure can be done without the need of any incisions. It also doesn't take as long to complete. The experience with this technique is limited, athough it is developing as a option
for those patients unable to tolerate the more prolonged procedure. 3) Another option is to implant a deep brain stimulator (a small electrode implanted into
thalamus that is connected to a programmable transmitter under the chest wall, like a pacemaker). By electrically interfering with the natural firing pattern of the nerve cells in this
area the tremor is electrically suppressed. This, if successful, will stop the tremor on the opposite side of the body. There are, as with any surgery, possible side effects that need to be discussed and considered.
Cerebellar Tremor(frequency 3-4 Hz) Tremors can result from damage to the cerebellum. The cerebellum is a structure attached to
the back of the brainstem, inside the skull. It is made up of two halves, the hemispheres. The main function of the cerebellum is to co-ordinate motor activity. When one hemisphere
is damaged there is a loss of co-ordination on the same side of the body. Tremors can result by damage to the cerebellar outflow pathways. These true rhythmic
tremors will be absent at rest, and maximal with activity. Some cerebellar tremors are more obvious with posturing and at rest ("rubral" or red nucleus tremors). Cerebellar tremors due
to lesions of the hemispheres of the cerebellum tend to be more irregular, erratic and non rhythmic "tremors" with action. Treatment:
Cerebellar tremors are very difficult to treat. Weighting the arms by placing something heavy around the wrists can help. Medication Options:
Although no medications work well; Topamax, Isoniazid, Clonazepam, Tegretol, Amantadine and Buspirone have been suggested. 1) Steriotactic thalmotomy is a procedure that surgically destroys the very small area deep
within the brain that causes the tremor (the thalamus). This, if successful, will stop the tremor on the opposite side of the body. There are, as with any surgery, possible side effects
that need to be discussed and considered. 2) Gamma knife (radiosurgery) thalmotomy is also a procedure that destroys a very localized area in the brain by applying many small radiation beams into one focussed spot. This
procedure can be done without the need of any incisions. It also doesn't take as long to complete. The experience with this technique is limited, athough it is developing as a option
for those patients unable to tolerate the more prolonged procedure. 3) Another option is to implant a deep brain stimulator (a small electrode implanted into
thalamus that is connected to a programmable transmitter under the chest wall, like a pacemaker). By electrically interfering with the natural firing pattern of the nerve cells in this
area the tremor is electrically suppressed. This, if successful, will stop the tremor on the opposite side of the body. There are, as with any surgery, possible side effects that need to be discussed and considered.
Others:
Some tremors persist at rest, with posture, and with action. These tremors are usually associated with medication side effects, hepatic failure (eg. Wilson's Disease), or psychogenic (stress induced).
Other rare conditions that can mimic tremors are:
Myorhythmia, Rhythmic Myoclonus, Clonus. Task specific tremors
Epilepsia Partialis Continuans Head bobbing with 3rd ventricular cysts Orthostatic Tremor
