Advancements in Non-Invasive Intracranial Pressure Monitoring for Spaceflight-Associated Neuro-Ocular Syndrome and their Implications for Neurological Monitoring

Abstract

Long-duration spaceflight has revealed a distinctive constellation of neuro-ocular abnormalities, collectively known as Spaceflight-Associated Neuro-Ocular Syndrome (SANS). These are hypothesized to result from cephalad fluid shifts in microgravity, leading to altered cerebrovascular dynamics and suspected mild elevations in intracranial pressure (ICP). Invasive ICP monitoring techniques are unsuitable for spaceflight, prompting the development and validation of non-invasive alternatives, including optic nerve sheath diameter (ONSD) ultrasound and transcranial Doppler (TCD), which offer practical and reliable surrogates for estimating ICP. When combined, these methods can improve diagnostic accuracy and enable multimodal neuromonitoring. Integration of rapidly advancing artificial intelligence (AI) models into ONSD and TCD systems can further enhance precision, reduce operator dependence, and enable automated trend analysis. This paper examines current advances in non-invasive ICP monitoring within space medicine, evaluates their readiness for operational deployment, and identifies key challenges related to standardization, calibration, and validation. These breakthroughs hold substantial promise for supporting astronaut health during spaceflight and planetary missions, while also advancing neurocritical care on Earth.