Key Facts

Biomedical engineers and neuroscientists developed a wearable, non-invasive optical sensor integrating Photoplethysmography (PPG) and Near-Infrared Spectroscopy (NIRS) to monitor Cerebral Blood Flow (CBF) and assess biological brain ageing. The headband-like device projects light at specific near-infrared wavelengths through the human skull, measuring light absorption fluctuations caused by oxygenated and deoxygenated haemoglobin. By tracking microvascular pulsatility and cerebral haemodynamics during cognitive tasks, the sensor generates real-time biomarkers of neurovascular health. While researchers caution that CBF metrics cannot definitively predict dementia or neurodegenerative onset in isolation, the breakthrough offers affordable clinical screening for early cerebrovascular decline.

GK Context

Cerebral Blood Flow (CBF) delivers oxygen and glucose necessary to sustain normal metabolic function in brain tissue, consuming approximately 20% of the body's total resting energy despite the brain accounting for only 2% of body mass. Photoplethysmography (PPG) is an optical volumetric measurement technique widely used in smartwatches to measure peripheral pulse, while Near-Infrared Spectroscopy (NIRS) exploits the optical window (700–900 nm) where biological tissue is relatively transparent to light, allowing deep tissue oxygenation monitoring without hazardous ionising radiation.