medical devices for use in treating neurodegenerative diseases, neurocognitive diseases, Alzheimer's disease, symptom of stroke, symptom of traumatic brain injury, cerebrospinal fluid dynamics dysfunction, neuroinflammation, and increased intracranial fluid; therapeutic devices using cerebrospinal fluid motion, cerebrospinal fluid pressure changes, spinal motion, respiratory inhalation and exhalation, improved performance of lymphatic system, improved performance of glymphatic system, improved posture, improved glymphatic clearance, improved drug delivery in cerebrospinal fluid, improved drug delivery in blood, and lowering brain wave activity to provide relief from neurodegenerative diseases, neurocognitive diseases, Alzheimer's disease, symptom of stroke, symptom of traumatic brain injury, cerebrospinal fluid dynamics dysfunction, neuroinflammation, and increased intracranial fluid; and diagnostic devices, namely, medical diagnostic apparatus for testing cerebrospinal fluid dynamics