What is the diagnosis for a patient with slight tremors while performing actions or writing, without ataxia, and negative results on the glabellar (glabellar tap test) and Romberg (Romberg test) tests?

Essential Tremor (Action Tremor)

Based on the clinical presentation of tremor occurring during action (writing, performing tasks) with negative Romberg test, negative glabellar tap, and absence of ataxia, the diagnosis is essential tremor. 1, 2

Clinical Reasoning

The key diagnostic features that point to essential tremor include:

• Action tremor during voluntary movement (writing, performing tasks) is the hallmark of essential tremor, which characteristically presents as postural and action tremor involving the arms and hands 1, 3

• Negative Romberg test excludes proprioceptive/sensory ataxia, which would worsen significantly with eye closure due to loss of visual compensation for impaired position sense 4, 5

• Absence of ataxia rules out cerebellar pathology, as cerebellar ataxia would show persistent unsteadiness regardless of visual feedback 4

• Negative glabellar tap test helps exclude Parkinson's disease, where this sign (Myerson's sign) is often positive due to loss of habituation 6

Distinguishing from Key Differential Diagnoses

Parkinson's Disease - Excluded

• Parkinson's disease typically presents with resting tremor (tremor at rest that improves with action), which is the opposite pattern seen here 1, 3
• The negative glabellar tap test further argues against parkinsonism 6

Cerebellar Ataxia - Excluded

• Cerebellar ataxia would present with intention tremor (worsening as the limb approaches a target) plus additional cerebellar signs like dysmetria, dysdiadochokinesis, or truncal instability 7, 4
• The absence of ataxia effectively rules this out 4

Proprioceptive Ataxia - Excluded

• This would show a positive Romberg test with marked worsening when visual input is removed 5
• The negative Romberg test excludes dorsal column or peripheral sensory pathway dysfunction 5

Enhanced Physiologic Tremor - Consider

• While possible, the description of "slight tremors" during specific actions is more consistent with mild essential tremor rather than enhanced physiologic tremor, which is typically finer, faster, and more generalized 3

Clinical Pearls

Common diagnostic pitfall: 30-50% of patients labeled with essential tremor actually have other diagnoses, most commonly Parkinson's disease or dystonia 2. The bilateral action tremor pattern for at least 3 years, absence of isolated head/voice tremor, and absence of task-specific features are necessary for confident diagnosis 1.

Action tremor characteristics in essential tremor:

• Bilateral involvement is typical (though may be asymmetric initially) 1
• Worsens with sustained postures and goal-directed movements 1, 3
• Does NOT significantly worsen with eye closure (unlike sensory ataxia) 4, 5
• Does NOT improve with action (unlike parkinsonian rest tremor) 3