Spaceflight stressors, including depression, can significantly disrupt one's ability to function effectively and efficiently, and associated performance deficits can seriously jeopardize space mission success. Mission success can be jeopardized either directly, from the potentially life-threatening consequences of lapses in performance, or indirectly, by adding to the workload and stress of other crewmembers. The substantial likelihood and potentially serious consequences of depression during spaceflight explains why human performance failure due to neurobehavioral problems is a high-priority risk for all mission types (International Space Station, moon, Mars).

A variety of therapies are already available, including preventative measures, medications and psychological consultations with ground crews. However, current methods to decide whether a therapy needs to be used rely heavily on subjective self-report. The biological basis of mood disorders suggests neural biomarkers may provide a more objective method for assessing depression and associated performance deficits. This project aims to identify neural biomarkers sensitive to, and specific for, both depression detection and depression severity assessment.

Since there is currently no reliable way to monitor brain status or function in spaceflight, an important component of our project will be technology development focused on the evaluation and validation of a flight-capable, noninvasive neuroimaging technology: near-infrared neuroimaging (NIN). The aims for this project therefore seek to:

1. Evaluate the ability of near-infrared neuroimaging to more objectively detect clinical depression and assess its severity.
2. Improve our existing mobile near-infrared neuroimaging technology to enable more robust mobile monitoring of brain hemodynamics.

In Year 2, we began our neuroimaging data collection and also focused on NIN technology development. We completed a second generation NIN prototype device and successfully tested it, both in the laboratory and during a parabolic flight, for sensitivity to brain hemodynamics. In the coming year, we plan to complete the neuroimaging of depressed participants and will continue to advance the capabilities for NIN in mobile and spaceflight environments.

If successful, these activities are expected to have two primary impacts. First, identification of brain-based biomarkers for depression will move the countermeasure readiness level (CRL) of brain-based evaluation of depression from CRL 2 to CRL 3. Once depression is objectively identified, there are already suitable depression countermeasures available for deployment in flight (including medications and psychological consults), plus Dr. Cartriene's computer-based therapy in development. Identification of brain-based biomarkers would be useful not only in spaceflight, but for the millions of individuals suffering from depression on Earth, by providing a more objective and potentially more readily accessible method for evaluating depression.

Second, our technology development efforts have already moved the technology readiness level (TRL) of near-infrared neuroimaging to TRL 5, and we are expecting to reach TRL 6 with coming advances and studies. Our use of relatively inexpensive and unobtrusive NIN technology will enable brain imaging and monitoring not only during spaceflight, but also in a variety of Earth-based contexts including in-office neuroimaging, rural areas and even under-served communities or first-responder contexts.

Earth-based Applications of Research Project
Successful completion of this project would lead to the following Earth-relevant benefits:

1. Depression Biomarkers: We seek to identify biomarkers that are suitable for depression diagnosis and assessing depression severity. If a reliable near-infrared neuroimaging (NIN)-based biomarker is identified, this would provide initial validation of the lower cost NIN-based evaluation of depressed individuals. Such brain-based biomarkers could then be measured in an office setting and at relatively low cost, thereby enabling access to such capabilities in broader regions than currently possible, including rural or underserved communities.
2. Mobile Neuroimaging: Developing appropriate technologies can enable neuroimaging in mobile environments, including spaceflight analogs and spaceflight itself. Such technologies have the potential to impact a wide range of novel brain monitoring applications on Earth as well, ranging from mobile epilepsy monitoring, to monitoring treatment efficacy via brain imaging in a doctor's office, to battlefield or first-responder head trauma evaluations. It would also lead to generally more available, less expensive methods for diagnosing, monitoring, and treating depression or other disorders involving alterations in brain function. NIN is of particular promise as a brain-imaging technology as it is sufficiently low cost, robust and portable, so that it could be made readily available in diverse operational environments including urban, rural and remote settings.

Project Description
NASA Task Book Entry