Integrating functional near-infrared spectroscopy in the characterization, assessment, and monitoring of cancer and treatment-related neurocognitive dysfunction

•Cancer & treatment-related neurocognitive dysfunction (CRND) is a serious problem.•Reliable and psychometrically validated measures of CRND are lacking.•Neuropsychological tests do not generally support self-reported experience of CRND.•Neuroimaging data on CRND have shown evidence of the brain possibly compensating.•fNIRS can bridge the gap between self-reported CRND and neuropsychological tests.

Cancer and cancer treatment-related neurocognitive dysfunction (CRND) (e.g., impairments in key cognitive domains of attention, memory, processing speed, and executive function), commonly referred to as “chemobrain” or “chemo-fog”, can negatively impact patients' psychosocial functioning and quality of life. CRND is a debilitating and enduring adverse effect experienced by 17% to 75% of patients during and after completion of treatment. However, few studies have systematically characterized and tested interventions to treat CRND. This paucity of data is due, at least partly, to difficulties understanding its etiology and a lack of consensus studies on best methods for assessing the presence and severity of CRND. This paper presents a comprehensive model for characterizing, assessing and monitoring cancer and treatment-related neurocognitive dysfunction, with functional near-infrared spectroscopy (fNIRS) as an important component of this model. The benefits of fNIRS to the characterization and longitudinal assessment and monitoring of CRND are discussed. Strategies for integrating optical imaging spectroscopy in biobehavioral oncology research, strength and limitations, and directions for future CRND studies using fNIRS are examined.