Review: Brain and muscle near infrared spectroscopy/imaging techniques

This review is an introduction to functional near infrared spectroscopy techniques and instrumentation which are commonly used for the estimation of haemoglobin concentration in muscle and brain cortex. Three approaches are considered: continuous wave, frequency domain and time domain near infrared spectroscopy. The different techniques are briefly analysed from a theoretical point of view in order to understand their capabilities and drawbacks. Some of the instrumentation commonly used is considered, presenting the main characteristics of the different techniques, their similarities and principal differences. © IM Publications LLP 2012.