Spatial correspondence of cortical activity measured with whole head fNIRS and fMRI: Toward clinical use within subject.

Functional near infrared spectroscopy (fNIRS) and functional magnetic resonance imaging (fMRI) both measure the hemodynamic response, and so both imaging modalities are expected to have a strong correspondence in regions of cortex adjacent to the scalp. To assess whether fNIRS can be used clinically in a manner similar to fMRI, 22 healthy adult participants underwent same-day fMRI and whole-head fNIRS testing while they performed separate motor (finger tapping) and visual (flashing checkerboard) tasks. Analyses were conducted within and across subjects for each imaging approach, and regions of significant task-related activity were compared on the cortical surface. The spatial correspondence between fNIRS and fMRI detection of task-related activity was good in terms of true positive rate, with fNIRS overlap of up to 68 % of the fMRI for analyses across subjects (group analysis) and an average overlap of up to 47.25 % for individual analyses within subject. At the group level, the positive predictive value of fNIRS was 51 % relative to fMRI. The positive predictive value for within subject analyses was lower (41.5 %), reflecting the presence of significant fNIRS activity in regions without significant fMRI activity. This could reflect task-correlated sources of physiologic noise and/or differences in the sensitivity of fNIRS and fMRI measures to changes in separate (vs. combined) measures of oxy and de-oxyhemoglobin. The results suggest whole-head fNIRS as a noninvasive imaging modality with promising clinical utility for the functional assessment of brain activity in superficial regions of cortex physically adjacent to the skull.

Comparison of Whole-Head Functional Near-Infrared Spectroscopy With Functional Magnetic Resonance Imaging and Potential Application in Pediatric Neurology.

BACKGROUND: Changes in cerebral blood flow in response to neuronal activation can be measured by time-dependent fluctuations in hemoglobin species within the brain; this is the basis of functional magnetic resonance imaging (fMRI) and functional near-infrared spectroscopy (fNIRS). There is a clinical need for portable neural imaging systems, such as fNIRS, to accommodate patients who are unable to tolerate an MR environment. OBJECTIVE: Our objective was to compare task-related full-head fNIRS and fMRI signals across cortical regions. METHODS: Eighteen healthy adults completed a same-day fNIRS-fMRI study, in which they performed right- and left-hand finger tapping tasks and a semantic-decision tones-decision task. First- and second-level general linear models were applied to both datasets. RESULTS: The finger tapping task showed that significant fNIRS channel activity over the contralateral primary motor cortex corresponded to surface fMRI activity. Similarly, significant fNIRS channel activity over the bilateral temporal lobe corresponded to the same primary auditory regions as surface fMRI during the semantic-decision tones-decision task. Additional channels were significant for this task that did not correspond to surface fMRI activity. CONCLUSION: Although both imaging modalities showed left-lateralized activation for language processing, the current fNIRS analysis did not show concordant or expected localization at the level necessary for clinical use in individual pediatric epileptic patients. Future work is needed to show whether fNIRS and fMRI are comparable at the source level so that fNIRS can be used in a clinical setting on individual patients. If comparable, such an imaging approach could be applied to children with neurological disorders.

Depression Severity and Depression Stigma Among Students: A Survey of Universities in Five Countries.

In the university setting, mental disorders have come under greater scrutiny and more attention has been given toward addressing the social stigmas associated with mental illness in an effort to promote mental well-being and improve mental health care delivery on-campus. Depression has been previously linked to a reduction in quality of life, suicidal ideation, and poor academic performance. However, few studies have directly compared the burden of depression or stigmatized views between multiple universities. As a result, this cross-sectional study of university students from five countries was performed to determine the burden of depressive disorders, the stigmatizations of beliefs related to depression, and international variation. A questionnaire consisting of a sociodemographic survey, Patient Health Questionnaire-9 (PHQ-9), and Depression Stigma Scale (DSS) was distributed via multiple routes to undergraduate and graduate students at institutions in the United States, Taiwan, United Arab Emirates, Egypt, and Czech Republic. The point prevalence of depression was determined by using the algorithm scoring method of the PHQ-9. Depression severity was determined according to the summed-item scoring method of the PHQ-9. The degree of stigmatization of beliefs was determined by continuous scores on the DSS subscales for personal and perceived stigma. Differences in depression severity, personal stigma, and perceived stigma were determined according to analysis of variance and further studied using post hoc Tukey's tests. Responses were collected from students in the United States (n = 593), United Arab Emirates (n = 134), Taiwan (n = 217), Egypt (n = 105), and Czech Republic (n = 238). Of 1287 responses, 30.7% (n = 396) screened positive for a depressive disorder: 18.0% (n = 232) for major depressive disorder and 12.7% (n = 164) for another depressive disorder. Depression severity differed internationally (p < 0.001). Emirati students significantly exhibited most depression followed by Czech, American, and Taiwanese students (all ps < 0.001). There was also a difference between students of different countries in terms of personal stigma (p < 0.001), with Emirati students holding more stigmatized personal views than Czech, American, Egyptian, and Taiwanese students (all ps < 0.001). Students similarly demonstrated differences in terms of personal stigma (p < 0.001). Egyptian students exhibited the most perceived stigma followed by Emirati, Taiwanese, American, and Czech students (all ps < 0.001). These findings suggest a high point prevalence of depression among university students and differences in the severity of depression, which has implications for the delivery of mental health care in this population. There were significant differences in terms of personal and perceived stigma between university students, indicating resource allocation for university-based campaigns to reduce depression stigma may need to be tailored to the population. After implementation of stigma reduction programs, future follow-up surveys can be done to compare degrees of stigma before and after the intervention.

Functional Near-Infrared Spectroscopy and Its Clinical Application in the Field of Neuroscience: Advances and Future Directions.

Similar to functional magnetic resonance imaging (fMRI), functional near-infrared spectroscopy (fNIRS) detects the changes of hemoglobin species inside the brain, but via differences in optical absorption. Within the near-infrared spectrum, light can penetrate biological tissues and be absorbed by chromophores, such as oxyhemoglobin and deoxyhemoglobin. What makes fNIRS more advantageous is its portability and potential for long-term monitoring. This paper reviews the basic mechanisms of fNIRS and its current clinical applications, the limitations toward more widespread clinical usage of fNIRS, and current efforts to improve the temporal and spatial resolution of fNIRS toward robust clinical usage within subjects. Oligochannel fNIRS is adequate for estimating global cerebral function and it has become an important tool in the critical care setting for evaluating cerebral oxygenation and autoregulation in patients with stroke and traumatic brain injury. When it comes to a more sophisticated utilization, spatial and temporal resolution becomes critical. Multichannel NIRS has improved the spatial resolution of fNIRS for brain mapping in certain task modalities, such as language mapping. However, averaging and group analysis are currently required, limiting its clinical use for monitoring and real-time event detection in individual subjects. Advances in signal processing have moved fNIRS toward individual clinical use for detecting certain types of seizures, assessing autonomic function and cortical spreading depression. However, its lack of accuracy and precision has been the major obstacle toward more sophisticated clinical use of fNIRS. The use of high-density whole head optode arrays, precise sensor locations relative to the head, anatomical co-registration, short-distance channels, and multi-dimensional signal processing can be combined to improve the sensitivity of fNIRS and increase its use as a wide-spread clinical tool for the robust assessment of brain function.

Near-infrared spectroscopy muscle oximetry of patients with postural orthostatic tachycardia syndrome.

Postural orthostatic tachycardia syndrome (POTS) is a disabling condition characterized by orthostatic intolerance with tachycardia in the absence of drop-in blood pressure. A custom-built near-infrared spectroscopy device (NIRS) is applied to monitor the muscle oxygenation, noninvasively in patients undergoing incremental head-up tilt table (HUT). Subjects (6 POTS patients and 6 healthy controls) underwent 30 mins of 70°on a HUT. The results showed a significant difference in deoxyhemoglobin (Hb), change-in-oxygenation (ΔOxy) and blood volume (ΔBV) between patients and healthy controls. However, oxyhemoglobin (HbO2) showed a significantly faster rate of change in the healthy controls during the first 10 mins of the tilt and during the recovery. This NIRS muscle oximetry tool provides quantitative measurements of blood oxygenation monitoring in diseases such as POTS.

Monitoring hemodynamic changes in stroke-affected muscles using near-infrared spectroscopy.

The oxygenation level of a tissue is an important marker of the health of the tissue and has a direct effect on performance. It has been shown that the blood flow to the paretic muscles of hemiparetic post-stroke patients is significantly reduced compared to non-paretic muscles. It is hypothesized that hemodynamic activity in paretic muscles is suppressed as compared to non-paretic muscles, and that oximetry can be used to measure this disparity in real-time. In order to test this hypothesis, a custom-made oximetry device was used to measure hemodynamic activity in the forearm extensor muscles in post-stroke patients' paretic and non-paretic sides and in a control population during three exercise levels calibrated to the subject's maximum effort. The change in oxygenation (ΔOxy) and blood volume (ΔBV) were calculated and displayed in real-time. Results show no apparent difference in either ΔOxy or ΔBV between control subjects' dominant and non-dominant muscles. However, the results show a significant difference in ΔOxy between paretic and non-paretic muscles, as well as a significant difference between normalized post-stroke and control data. Further work will be necessary to determine if the observed difference between the paretic and non-paretic muscles changes over the course of physical therapy and can be correlated with functional improvements.

Reflective team supervision after a frightening event on a psychiatric crisis service.

OBJECTIVE: The authors demonstrate the value of reflective team supervision as part of the informal curriculum in an emergency psychiatry setting after a potentially traumatizing adverse event. METHOD: The article gives a case presentation of a violent adolescent who eloped from his hospital Emergency Department and provides a description of team supervision sessions that facilitated informal learning for residents and medical students after this event. RESULTS: Reflective team supervision sessions after this event resulted both in improved resident well-being and learning opportunities, as well as hospital quality improvement designed to prevent future elopements. CONCLUSIONS: Reflective team supervision can be an essential component of trainee education to enhance residents' well-being and to promote both systems-based practice and practice-based learning. This can be an excellent forum to explore themes of humility, self-reflection, and professional growth.