Aging impact on brain biomechanics with applications to hydrocephalus

Area of Science:

• Biomedical Engineering
• Neurology
• Computational Mechanics

Background:

• Hydrocephalus pathogenesis is age-dependent.
• Previous models used the fractional Zener model to study cerebrospinal fluid pulsations.
• Age-specific mechanical brain properties are crucial for understanding hydrocephalus.

Purpose of the Study:

• Determine mechanical parameters for the fractional Zener model in infant and adult brains.
• Calculate brain tissue displacement under hydrocephalus onset conditions.
• Investigate the role of age-dependent elastic modulus in hydrocephalus development.

Main Methods:

• Utilized age-dependent shear complex modulus data.
• Calculated brain tissue displacement using a fractional Zener model.
• Proposed a new boundary condition for infant brain models.

Main Results:

• The steady-state elastic modulus increases from 621 Pa in infants to 955 Pa in young adults.
• Infant brain models with stress-free outer boundaries yielded unphysical displacements.
• A lower steady-state elastic modulus correlates with increased susceptibility to hydrocephalus.

Conclusions:

• The steady-state elastic modulus is a key parameter in hydrocephalus development.
• Infant and potentially aged brains are more susceptible to large deformations due to lower elastic modulus.
• Age-specific mechanical properties are critical for accurate hydrocephalus modeling.