What is the frequency of falls in patients with corticobasal degeneration (CBD) and how are they managed?

Frequency of Falls in Corticobasal Degeneration (CBD)

Falls occur early in the disease course of corticobasal degeneration, typically within 2 years of symptom onset, and represent a significant cause of morbidity and mortality in these patients. 1

Clinical Course and Fall Timeline in CBD

Corticobasal degeneration is a rare, progressive neurodegenerative tauopathy that typically presents in the 5th to 7th decade of life. The disease follows a predictable pattern of milestone development:

• Initial symptoms often begin with gait disturbance (median 0.0 years from onset)
• Falls typically develop at a median of 2.0 years from symptom onset 1
• Other milestones follow a sequential pattern:
  • Behavioral changes (1.0 year)
  • Cognitive impairment (2.0 years)
  • Speech impairment (2.5 years)
  • Supranuclear gaze palsy (3.0 years)
  • Urinary incontinence (3.0 years)
  • Dysphagia (5.0 years)

The median survival time from symptom onset is approximately 7.0 years 1.

Characteristics of Falls in CBD

Falls in CBD have specific characteristics that differentiate them from other parkinsonian disorders:

• Early occurrence of frozen gait is highly predictive of CBD pathology (sensitivity 81.3%, specificity 84.4%) 1
• Falls are often associated with asymmetric limb apraxia and markedly impaired balance 2
• Falls frequently occur during transitional movements 2
• Unlike Progressive Supranuclear Palsy (PSP), early dysarthria is less common in CBD-related falls 1

Risk Factors for Falls in CBD

Several factors contribute to the high fall risk in CBD patients:

• Asymmetric progressive rigidity and apraxia
• Limb dystonia and myoclonus
• Impaired balance and postural instability
• Cognitive impairment (typically appearing around 2.0 years from onset)
• Gait abnormalities, particularly freezing of gait

Management of Falls in CBD

Management strategies should focus on:

1. Early Mobility Aids:

   • Introduction of a 4-wheeled walker early in the disease course 2
   • Supervision during ambulation, particularly in community settings

2. Exercise Interventions:

   • Regular participation in structured exercise programs has shown benefit in reducing fall frequency 2, 3
   • A long-term exercise program including:
     • Trunk and lower extremity stretching and strengthening
     • Upright balance exercises
     • Treadmill walking (both forward and backward)
     • Frequency: twice weekly for 1 hour sessions

3. Locomotor Training:

   • Treadmill training (with and without body-weight support) 2
   • Individual treadmill sessions (1 hour, once weekly) 3

4. Environmental Modifications:

   • Home safety assessment and modifications
   • Removal of fall hazards
   • Installation of grab bars and other assistive devices

Effectiveness of Interventions

Evidence suggests that consistent participation in exercise programs can significantly impact fall frequency and functional status:

• In a 10-year follow-up case report, falls decreased from 1.9 falls per month in year 1 to 0.3 falls per month in year 10 with regular exercise 3
• Maintained balance function and slowed decline in walking performance 2
• Prevented progression to wheelchair dependence 2

Clinical Monitoring

Regular assessment should include:

• Fall frequency monitoring (self-reported by patient and caregiver)
• Balance assessment (Berg Balance Scale, functional reach tests)
• Gait speed evaluation
• Monitoring for development of other milestones (cognitive decline, speech impairment)

Conclusion

Falls represent an early and significant problem in CBD, typically occurring within 2 years of symptom onset. Early intervention with mobility aids, structured exercise programs, and environmental modifications can reduce fall frequency and maintain functional independence longer than would be expected with the natural disease course. Regular monitoring and adjustment of interventions are essential as the disease progresses.