This report is the second part of a comprehensive two-part series aimed at reviewing an extensive and diverse toolkit of novel methods to explore brain health and function. While the first report focused on neurophotonic tools mostly applicable to animal studies, here, we highlight optical spectroscopy and imaging methods relevant to noninvasive human brain studies. We outline current state-of-the-art technologies and software advances, explore the most recent impact of these technologies on neuroscience and clinical applications, identify the areas where innovation is needed, and provide an outlook for the future directions.
Cerebral autoregulation (CA) as a mechanism to protect the brain from ischemia or hypoperfusion may play an important role related to post-stroke interventions such as the physiotherapy and the outcome. Here, we present a non-invasive assessment of the CA status by diffuse correlation spectroscopy (DCS) measures calculating the DCS moving correlation coeffcient CBFx with arterial blood pressure (ABP). The measurements are performed during the first mobilization after the onset of the symptoms. The CBFx is compared to values obtained in a healthy population showing signicantly higher values in the stroke population. This may pave the way for personalized treatment.
A limiting factor for personalizing therapies in stroke patients is the inability to continuously monitor the cerebral status of patients. In particular, potential impairment of cerebral autoregulation (CA) in these patients may incur certain risks during their mobilization. We have used hybrid diffuse optical techniques to measure new biomarkers related to CA status as well as metabolic health in a large cohort of stroke patients in order to determine biomarkers indicative of clinical improvement. If validated, these results can pave the way towards personalization of stroke therapy based on direct measures of cerebral health.
KEYWORDS: Hemodynamics, Cognitive informatics, Transparent conductors, Physiology, Neuroimaging, Data acquisition, Time resolved spectroscopy, Spectroscopy, Neuroscience, Medical research
We present a study investigating the effect of non-medical face masks (FFP2 and surgical) on cerebral hemodynamics measured by transcranial hybrid diffuse optics, and on systemic physiology in 13 healthy adults (age: 23-33 years).
We present an update on a clinical study on 200 stroke patients where hybrid diffuse optics is used to monitor microvascular cerebral hemodynamics and derived parameters during postural changes twenty-four hours after stroke onset.
Diffuse correlation spectroscopy (DCS) is an emerging diffuse optical technique that quantifies microvascular blood flow. In spite of the wide range of clinical/research applications, DCS instrumentation is not yet standardized. In this study, we have analyzed the effect of experimental parameters as the measurement duration time and the number of detectors, at different photon count-rates, on the precision of a DCS experiment. This provides a recipe for finding device and experimental settings that optimize the precision while balancing cost and temporal resolution.
Intracranial pressure (ICP) is a critical biomarker measured invasively with the risk of complications. There is a need for non-invasive methods to estimate ICP. Diffuse correlation spectroscopy (DCS) allows the non-invasive measurement of pulsatile, microvascular cerebral blood flow which contains information about ICP. Recently, our proof-of-concept study used machine-learning to deduce ICP from DCS signals to estimate ICP resulting in excellent linearity and a reasonable accuracy (±4 mmHg). Here, we extend to a multi-center (three centers) data set of adults with acute brain injury (N=34). We will present the results from the complete data set as new data flows in.
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