The Canadian Movement Disorder Group
Tremor

Definition of tremor:  "A rhythmical oscillation of a body part "   

6 Main Types

(More detailed information can be found below)

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 withdrawal) 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, get adequate sleep an avoid going hungry).  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 for this tremor can be passed from generation to generation.  Fifty percent of children of an affected parent will inherit the tendency to get the tremor (autosomal dominant inheritance).  The  tremor will usually affect both sides but may be asymmetric..  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 rest or relaxation of the arms.  It is more apparent when the patient holds their arms out straight (posturing) or when they are performing activities (intention).

    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 withdrawal) will accentuate essential tremor.

    Treatment:

    Often no treatment is necessary other than reassurance once the diagnosis is made.  Some counseling 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 2-3 hrs).

    2) Daily Propranolol (doses > 120 mgs/day are usually needed when used chronically). Note this is not a safe option in asthmatics.

    3)Daily Primidone.

    4) Daily Propranolol and Primidone combined

    5) Daily Topiramate (Topamax)

    6) If the above are ineffective gabapentin, diamox, pregabalin, clonidine, amantidine, clonazepam, clozapine have been suggested as other options.

    Surgical Options:

    1) Steriotactic radio frequency 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. this will only treat the tremor on the opposite side of the body. Doing this procedure on both sides can risk significant speech impairment.

    2) Gamma knife (radio surgery) 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 and remains under investigation.

    3) Another option is to implant a deep brain stimulator (DBS) which is 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.

    Surgical Options:

    1) Steriotactic radio-frequency 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. this will only treat the tremor on the opposite side of the body. Doing this procedure on both sides can risk significant speech impairment.

    2) Gamma knife (radio-surgery) 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 and remains under investigation.

    3) Another option is to implant a deep brain stimulator (DBS) which is 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.  They can be associated with a variety of types of ataxia, 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 coordinate motor activity.  When one hemisphere is damaged there is a loss of coordination 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 callled Holme's tremor 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.

    Surgical Options:

    1) Steriotactic radio-frequency 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. this will only treat the tremor on the opposite side of the body. Doing this procedure on both sides can risk significant speech impairment.

    2) Gamma knife (radio-surgery) 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 and remains under investigation.

    3) Another option is to implant a deep brain stimulator (DBS) which is 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.

Dystonic Tremor

    Not infrequently dystonic movements can be associated with a rhythmic oscillation. This combination of movements would be called Dystonic Tremor. The main treatment would be to treat the dystonia.

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 due to functional disorders.

    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

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