What can cause changes in handwriting?

Causes of Handwriting Changes

Handwriting changes can result from neurodegenerative diseases (particularly Parkinson's disease, Wilson disease, and Alzheimer's disease), multiple sclerosis, or focal brain lesions affecting language and visuospatial centers.

Neurodegenerative Causes

Parkinson's Disease and Parkinsonian Disorders

• Micrographia (progressively smaller handwriting) is the hallmark feature, representing cramped, small handwriting similar to what occurs in Parkinson disease 1
• Handwriting abnormalities extend beyond size to include reduced velocity, decreased fluency, increased stroke duration, and impaired motor anticipation 2
• These changes reflect impaired "open-loop" automatic performance of sequential hand movements 3
• Patients show inability to anticipate future movements during writing sequences, indicating deficits in parallel processing of motor sequence components 4

Wilson Disease

• Handwriting deterioration occurs as an early neurologic manifestation, typically presenting in the third decade but can appear in childhood 1
• Micrographia develops as part of the neurologic syndrome, often accompanied by tremor, lack of motor coordination, dysarthria, and dystonia 1
• Earlier subtle findings in pediatric patients include deterioration in schoolwork and inability to perform activities requiring hand-eye coordination 1
• Wilson disease must be excluded in any patient aged 3-55 years with unexplained neurological symptoms, especially when combined with liver abnormalities 1

Alzheimer's Disease and Related Dementias

Progressive Aphasic Syndromes

• Agraphia (impaired writing) occurs as part of progressive aphasic syndromes, particularly in logopenic variant primary progressive aphasia due to Alzheimer's disease 1
• Writing impairment manifests alongside speech and language difficulties including word-finding problems, agrammatism, and impaired comprehension 1

Posterior Cortical Atrophy

• Agraphia develops with visuospatial dysfunction, alexia, acalculia, and limb apraxia in posterior cortical atrophy syndrome 1, 5
• The underlying pathology is usually Alzheimer's disease, sometimes frontotemporal lobar degeneration-corticobasal degeneration or Alzheimer's with Lewy bodies 1, 5
• Difficulty with writing occurs alongside inability to recognize faces or common objects and problems operating simple implements 1

Frontotemporal Dementia

• Writing difficulties can occur in behavioral variant frontotemporal dementia as part of executive dysfunction 1
• Speech, spelling, and writing errors develop when language functions are impaired 1

Inflammatory and Demyelinating Causes

Multiple Sclerosis

• Handwriting impairments in multiple sclerosis reflect both cognitive and sensorimotor deterioration 6
• Kinematic analysis reveals higher movement duration, fragmented velocity profiles, and increased jerk (reduced smoothness) 6
• Motor abilities and cognitive status both correlate with handwriting parameters, reflecting the multifactorial nature of the disease 6

Focal Neurological Lesions

Alexia with Agraphia

• Lesions of the left angular gyrus in the dominant parietal lobe cause combined reading and writing impairment 7
• Often associated with other language impairments as part of a progressive syndrome 7
• Neuroimaging (MRI) is crucial to identify the specific lesion location 7

Clinical Approach

When evaluating handwriting changes, consider:

• Age of onset: Wilson disease typically presents ages 3-55 years; Parkinson's disease usually later; Alzheimer's disease typically after age 65 1
• Pattern of change: Progressive micrographia suggests Parkinson's or Wilson disease; agraphia with language impairment suggests Alzheimer's-related aphasic syndrome 1, 2
• Associated features: Tremor and rigidity point to Parkinson's; liver disease with neurologic symptoms mandates Wilson disease evaluation; visuospatial problems suggest posterior cortical atrophy 1
• Neuroimaging findings: MRI showing frontal-parietal atrophy suggests frontotemporal dementia; posterior cortical changes suggest posterior cortical atrophy; basal ganglia abnormalities suggest Wilson disease 7, 8

Critical pitfall: Do not dismiss handwriting deterioration in children or young adults as benign—this may represent early Wilson disease, which requires urgent diagnosis and treatment to prevent irreversible neurologic damage 1