The mechanical state of intracranial tissues in elderly subjects studied by imaging CSF and brain pulsations

The biomechanical properties of intracranial tissues influence the mechanic al coupling of brain and CSF oscillations to the driving vascular pulsation s. Dynamic phase contrast MRI was used to measure the transfer functions th at characterize these couplings in normal elderly subjects and patients wit h Alzheimer's disease. The transfer functions of bath groups were significa ntly different from the previously reported transfer functions of normal yo ung subjects. The data show that vascular pulsations tend to cause greater spinal cord movements and smaller CSF oscillations in the older subjects th an in the younger ones. These results are likely to be due to age-related c hanges in the mechanical state of intracranial tissues. (C) 2000 Elsevier S cience Inc. All rights reserved.