From the Research
Essential tremor is typically bilateral, affecting both sides of the body, rather than unilateral. While it can begin on one side and may be more pronounced on one side than the other, true unilateral essential tremor that permanently affects only one side of the body is uncommon. Essential tremor usually presents as a symmetric or asymmetric bilateral tremor that most commonly affects the hands and arms during voluntary movements or when maintaining a posture, and can also involve the head, voice, and occasionally the legs. If a tremor is strictly unilateral and remains so over time, doctors would typically consider other diagnoses such as Parkinson's disease, dystonic tremor, or a structural lesion in the brain. The bilateral nature of essential tremor relates to its pathophysiology, which involves abnormal oscillatory activity in the cerebello-thalamo-cortical pathways on both sides of the brain, though the exact mechanisms remain incompletely understood 1.
Some key points to consider in the diagnosis and treatment of essential tremor include:
- The first line of treatment for limb tremor is pharmacotherapy with propranolol or primidone 2
- Botulinum toxin injections are likely efficacious for limb, voice and head tremor but are associated with side effects 2
- Surgical interventions include deep brain stimulation; magnetic resonance-guided focused ultrasound and thalamotomy for unilateral and deep brain stimulation for bilateral procedures 2
- Recent consensus classification for essential tremor has included a new subgroup, 'Essential tremor plus', who have associated subtle neurological 'soft signs', such as dystonic posturing of limbs and may require a different treatment approach 2
Anyone experiencing tremor should seek medical evaluation for proper diagnosis and treatment options. A thorough medical history, physical examination, and diagnostic tests may be necessary to determine the underlying cause of the tremor and to develop an effective treatment plan. In some cases, referral to a specialist, such as a neurologist, may be necessary to manage the condition effectively.