What is the treatment for intention tremor?

Treatment of Intention Tremor

Intention tremor is challenging to treat pharmacologically and responds poorly to standard tremor medications like propranolol, but surgical interventions—particularly thalamotomy—offer effective treatment for severe, refractory cases. 1

Understanding Intention Tremor vs. Essential Tremor

Intention tremor differs fundamentally from essential tremor in both presentation and treatment response:

• Intention tremor is characterized by coarse, irregular tremor that worsens during goal-directed movements, often with a "wing-beating" appearance, and is typically accompanied by dysarthria and ataxic gait due to cerebellar pathology 1
• Essential tremor presents as bilateral action tremor of the arms and hands that occurs with sustained posture or movement, not specifically worsening with goal-directed tasks 1
• This distinction is critical because intention tremor is more challenging to treat pharmacologically than essential tremor 1

Pharmacological Treatment Approach

Limited Medication Options

Intention tremor may respond to certain medications, though evidence is limited compared to essential tremor treatment:

• Propranolol (80-240 mg/day) can be tried as it remains the most established tremor medication, though its efficacy for intention tremor is substantially lower than for essential tremor 2, 1
• Avoid beta-blockers in patients with chronic obstructive pulmonary disease, bradycardia, or congestive heart failure 2, 1
• Common adverse effects include fatigue, depression, dizziness, hypotension, exercise intolerance, and sleep disorders 2
• Primidone may be considered as an alternative, though evidence for intention tremor specifically is lacking 2

Important Medication Caveats

• Clinical benefits from primidone may not become apparent for 2-3 months, requiring an adequate trial period 2
• Women of childbearing age should be counseled about teratogenic risks (neural tube defects) with primidone 2
• In elderly patients, excessive heart rate reduction with beta-blockers may lead to serious adverse events 2

Non-Pharmacological Rehabilitation Strategies

Physical and occupational therapy with adaptive devices may help improve function when medications fail: 1

Rhythm Modification Techniques

• Superimpose alternative, voluntary rhythms on top of the existing tremor and gradually slow all movement to complete rest 3
• For unilateral tremor, use the unaffected limb to dictate a new rhythm (e.g., tapping/opening and closing the hand) to entrain the tremor to stillness 3
• Music can be introduced to dictate a rhythm to follow 3

Movement Strategy Modifications

• Assist the person to relax the muscles in the limb to prevent cocontraction 3
• Try to control tremor with the person at rest before moving on to activity 3
• Use gross rather than fine movements (which take more concentration), for example, handwriting retraining using a marker and large piece of paper or whiteboard with big lettering or patterns/shapes 3
• Discourage cocontraction or tensing of muscles as a method to suppress tremor, as this is unlikely to be a helpful long-term strategy 3, 2

Equipment Considerations

• Avoid aids and equipment in the acute phase, as they may interrupt normal automatic movement patterns and cause maladaptive functioning 2
• If aids are necessary for safety (e.g., safe hospital discharge), they should be: (1) considered short-term solutions; (2) issued with a minimalist approach; and (3) accompanied by a plan to progress from their use 3

Surgical Treatment for Refractory Cases

When medications fail due to lack of efficacy, side effects, or contraindications, surgical therapies should be considered: 2

Surgical Options Algorithm

For severe, medication-refractory intention tremor causing significant disability:

1. First-line surgical option: Magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy for unilateral tremor 2, 1

   • Shows sustained tremor improvement of 56% at 4 years 2, 1
   • Lower complication rate (4.4%) compared to radiofrequency thalamotomy (11.8%) and deep brain stimulation (21.1%) 2, 1
   • Early adverse effects include gait disturbance (36%) and paresthesias (38%), which decrease to 9% and 14% respectively by 1 year 2
   • Serious adverse events are rare (1.6%), with most adverse events being mild or moderate (98.4%) 2

2. MRgFUS contraindications (choose alternative if present):

   • Cannot undergo MRI 2, 1
   • Skull density ratio <0.40 2, 1
   • Need for bilateral treatment or previous contralateral thalamotomy 2, 1

3. Alternative surgical options:

   • Deep brain stimulation (DBS) for bilateral tremor or when MRgFUS is contraindicated 2, 1
   • DBS provides adjustable, reversible tremor control that can be optimized over time 2
   • Radiofrequency thalamotomy is available but carries higher complication risks than MRgFUS 2

Historical Surgical Evidence

Stereotactic ventralis lateralis (VL) thalamotomy has demonstrated effectiveness specifically for intention tremor:

• Contralateral targeted upper-extremity intention tremor remained absent or markedly reduced in 81.8% of cases (mean follow-up 23.4 months) in patients with multiple sclerosis, trauma, or stroke 4
• Persistent surgical morbidity was limited to mild, nondisabling dysarthrias in 2 patients 4
• VL thalamotomy carries low surgical risk and can be effective for properly selected patients with debilitating intention tremor 4

Treatment Algorithm Summary

For intention tremor management:

1. Trial of propranolol 80-240 mg/day for 3 months (if no contraindications) 2, 1
2. If inadequate response, consider primidone (allow 2-3 months for effect) 2
3. Implement physical/occupational therapy with rhythm modification techniques throughout 3, 1
4. For medication-refractory tremor causing significant disability, proceed to surgical evaluation 2, 1
5. Choose MRgFUS thalamotomy for unilateral tremor without contraindications 2, 1
6. Choose DBS for bilateral tremor or when MRgFUS is contraindicated 2, 1