Near infrared technology in neuroscience: past, present and future

Objective: To review past, present and future applications of near-infrared spectroscopy (NIRS) in clinical neuroscience. Methods: The literature and personal experience of the authors were critically reviewed in order to provide a balanced overview of the basic principles, clinical validation, previous experience and current use of NIRS in assessment of cerebral oxygenation in clinical neuroscience. Results: Recent technological advancements in transcranial cerebral oximetry (TCCO) are opening up a new promising avenue in clinical neuroscience. With its non-invasive nature, high reliability and uniqueness of gathered data, NIRS represents a very special modality in the neuroscience intensive care unit, angiography suite and the operating room. The hurdles of using this technology in clinical practice are discussed in detail. In addition, we evaluate some known limitations of NIRS and current controversies around its use. Lastly, several commercially available cerebral oximeters are presented. Conclusion: Despite remarkable developments in the NIRS technology and proven reliability of the cerebral oxygenation monitoring approach, TCCO remains mostly an adjuvant tool for neuroscience applications. Newer NIRS technologies have become a source of quantitative information about brain oxygenation, cerebral blood volume and flow. However, the clinical significance of this new information in the context of clinical neuroscience will need to be determined and further validation studies will need to be performed. [Neurol Res 2009; 31: 605-614]