What causes head or hand tremors?

Understanding Head and Hand Tremors: Causes and Classification

Tremors are rhythmic, involuntary oscillatory movements caused by alternating contraction of opposing muscle groups, and the specific pattern of tremor—whether it occurs at rest, with posture, or during movement—directly indicates the underlying cause. 1

Primary Classification by Activation Pattern

The most clinically useful approach divides tremors based on when they occur:

Rest Tremor (4-6 Hz)

• Parkinsonian tremor is the hallmark rest tremor that improves with voluntary movement 1, 2
• Typically affects hands and legs with a "pill-rolling" quality 3
• Caused by degeneration of dopaminergic neurons in the substantia nigra 4
• Look for accompanying rigidity and bradykinesia (slowness of movement) 4, 5

Critical pitfall: Not all rest tremors are Parkinson's disease—if prominent early falls, gait dysfunction, vertical gaze palsy, or poor levodopa response are present, consider atypical parkinsonism like progressive supranuclear palsy or multiple system atrophy 1, 4

Postural/Action Tremor (4-12 Hz)

• Essential tremor is the most common cause, worsening with goal-directed activity like drinking from a cup or writing 1, 2
• Affects approximately 50% of cases with hereditary transmission 6
• Involves hands primarily, but can affect head and voice 7, 3
• Enhanced physiologic tremor (faster, finer tremor) occurs with caffeine, medications (especially stimulants like methylphenidate), thyroid excess, or anxiety 5, 2

Kinetic/Intention Tremor

• Cerebellar tremor becomes progressively worse during goal-directed movements and does not stop with distraction 1
• Associated with dysarthria (slurred speech) and ataxic gait 1
• Results from cerebellar pathway lesions 3

Specific Tremor Patterns

Isolated Head Tremor

• More likely dystonic rather than essential tremor 2
• Dystonic tremor has irregular, jerky quality and may have directional predominance 2

Isolated Voice Tremor

• Considered part of the essential tremor spectrum 2
• Responds to botulinum toxin injections 7

Functional (Psychogenic) Tremor

Functional tremor is NOT a diagnosis of exclusion—specific clinical signs must be demonstrated: 1, 5

• Distractibility is the hallmark: tremor stops completely when attention is redirected 1, 5
• Variable frequency and amplitude 1, 5
• Sudden onset, often in context of stress 5
• Entrainability (tremor frequency changes to match voluntary rhythmic movements) 5

Management focuses on rehabilitation and explaining that functional neurological disorder is a real neurological condition, not "faking" 1

Secondary Causes to Exclude

Before diagnosing primary tremor disorders, rule out:

• Medications: Stimulants (methylphenidate, amphetamines), antipsychotics, lithium, valproate, SSRIs 5, 2
• Metabolic: Hyperthyroidism, hypoglycemia, hypercalcemia 4, 2
• Toxins: Alcohol withdrawal, caffeine excess 2, 6
• Wilson's disease: In younger patients with tremor plus dystonia, check serum ceruloplasmin and 24-hour urinary copper 1
• Peripheral neuropathy: Can cause tremor through proprioceptive dysfunction 3

Diagnostic Algorithm

Step 1: Determine activation pattern

• Rest tremor → Consider Parkinsonian disorders 1
• Postural/action tremor → Consider essential tremor or enhanced physiologic tremor 1
• Intention tremor → Consider cerebellar pathology 1

Step 2: Check for distractibility

• If tremor stops with distraction → Functional tremor 1, 5
• If tremor persists → Organic cause 1

Step 3: Assess for red flags

• Early falls, autonomic dysfunction, vertical gaze palsy → Atypical parkinsonism 1
• Dystonia, Kayser-Fleischer rings, liver disease → Wilson's disease 1
• Recent medication changes → Drug-induced tremor 5

Step 4: Family history

• Strong family history of tremor → Essential tremor more likely 5, 6

Common Pitfalls

• Do not confuse akathisia (severe restlessness from antipsychotics manifesting as pacing) with tremor 1
• Do not start tremor-specific medications before discontinuing potentially causative drugs like stimulants 5
• Do not assume bilateral involvement is required—essential tremor can begin unilaterally 5
• Do not overlook that cerebellar tremor does NOT stop with distraction, distinguishing it from functional tremor 1