Advancements in Noninvasive Blood Pressure Measurement: A Comprehensive Review of Cuffed, Cuffless, and Contactless Methods

Recent advances in non-invasive blood pressure (BP) monitoring are transforming the field, offering alternatives to traditional cuff-based methods that are often limited by discomfort and intermittent measurement. Following PRISMA guidelines, this review systematically analyses studies published between 2020 and 2024, categorizing current BP measurement techniques into cuff-based, cuffless, and contactless methods. Special attention is given to emerging technologies such as photoplethysmography (PPG), electrocardiography (ECG), bioimpedance, radar sensing, and remote PPG (rPPG), as well as the integration of artificial intelligence (AI) for signal processing and BP estimation. The review evaluates the comparative performance, clinical relevance, and readiness for real-world application across modalities. While cuffless and contactless approaches show significant promise for continuous and user-friendly monitoring, their accuracy often depends on calibration, multimodal data fusion, and robust algorithm design. Ethical considerations related to unobtrusive monitoring are also discussed. This work highlights current limitations, identifies future research opportunities, and supports the development of next-generation, AI-driven BP monitoring systems suitable for both clinical and consumer use.