Functional near-infrared spectroscopy (fNIRS), a growing neuroimaging modality, has been utilized over the past few decades to understand the neuronal behavior in the brain. The technique has been used to assess the brain hemodynamics of impaired cohorts as well as able-bodied. Neuroimaging is a critical technique for patients with impaired cognitive or motor behaviors. The portable nature of the fNIRS system is suitable for frequent monitoring of the patients who exhibit impaired brain activity. This study comprehensively reviews brain-impaired patients: The studies involving patient populations and the diseases discussed in more than 10 works are included. Eleven diseases examined in this paper include autism spectrum disorder, attention-deficit hyperactivity disorder, epilepsy, depressive disorders, anxiety and panic disorder, schizophrenia, mild cognitive impairment, Alzheimer’s disease, Parkinson’s disease, stroke, and traumatic brain injury. For each disease, the tasks used for examination, fNIRS variables, and significant findings on the impairment are discussed. The channel configurations and the regions of interest are also outlined. Detecting the occurrence of symptoms at an earlier stage is vital for better rehabilitation and faster recovery. This paper illustrates the usability of fNIRS for early detection of impairment and the usefulness in monitoring the rehabilitation process. Finally, the limitations of the current fNIRS systems (i.e., nonexistence of a standard method and the lack of well-established features for classification) and future research directions are discussed. The authors hope that the findings in this paper would lead to advanced breakthrough discoveries in the fNIRS field in the future.

中文翻译：

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功能性近红外光谱在医疗保健行业的应用：综述

功能性近红外光谱 (fNIRS) 是一种不断发展的神经成像模式，在过去的几十年中已被用于了解大脑中的神经元行为。该技术已被用于评估受损人群和健全人群的脑血流动力学。神经影像学是认知或运动行为受损患者的一项关键技术。fNIRS 系统的便携性适用于经常监测大脑活动受损的患者。本研究全面回顾了脑损伤患者：包括涉及患者人群和10多篇著作中讨论的疾病的研究。本文研究的 11 种疾病包括自闭症谱系障碍、注意力缺陷多动障碍、癫痫、抑郁症、焦虑和恐慌症、精神分裂症、轻度认知障碍、阿尔茨海默病、帕金森病、中风和外伤性脑损伤。对于每种疾病，讨论了用于检查的任务、fNIRS 变量和关于损伤的重要发现。还概述了通道配置和感兴趣的区域。及早发现症状的发生对于更好的康复和更快的恢复至关重要。本文说明了 fNIRS 在早期发现损伤方面的可用性以及在监测康复过程中的有用性。最后，讨论了当前 fNIRS 系统的局限性（即不存在标准方法和缺乏公认的分类特征）和未来的研究方向。