Wednesday October 14 2020, 9:00-10:00 AM EDT
The video recording of the session is below.
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| We1 | Turgut Durduran ICFO – The Institute of Photonics Sciences, Spain |
Hybrid diffuse optical technologies for neuro-monitoring in the clinics | Q&A |
| We2 | David Davies University Hospitals Birmingham, UK |
Applications of optics in brain trauma care | Q&A |
| We3 | Jeff Dunn University of Calgary, Canada |
NIRS as a tool for studying concussion | Q&A |
| We4 | Jana Kainerstorfer Carnegie Mellon University, USA |
Neuro-vascular coupling changes with cerebral perfusion pressure | Q&A |
| We5 | Mamadou Diop Western University, London, Canada |
Hyperspectral time-resolved NIRS in the adult head | Q&A |
| We6 | Colette McKay Bionics Institute, Melbourne, Australia |
fNIRS to fill unmet clinical need in audiology clinics | Q&A |
| We7 | Anne Gallagher Université de Montréal, Canada |
NIRS predictive markers of neurodevelopment | Q&A |
| WeP1 | Panel Discussion | Clinical Applications. Moderators David Highton & Ippeita Dan | Q&A |
Return to main chat page https://fnirs.org/conferences/fnirs-datablitz-2020-chat/
What kind of task do you use to examine prefrontal functions , and does it well reflect the effects of physical exercise and DCS?
We use a set of cognitive tasks while sitting (verbal fluency, stroop, boston naming etc) and tasks while walking (walking, walking + counting, walking + obstacles). The goal is not to evaluate the PFC during exercise but the PFC changes after therapy sessions.
I look forward to see the covid study results. Why you are limiting the study to the periphery?Plan to add cerebral oxygenation? cerebral blood flow?
Good question. There is evidence in the literature showing the relevance of peripheral muscles for ARDS , sepsis and other conditions. We are following up on that trail. We needed to be practical since we were starting in April 2020. I will be talking at SPIE COVID-19 platform about the details and results next week.
Important application! You seem to have difference of cortical activation among trauma patients. Are there distinct difference between normal subjects and trauma patients?
Great, work! When comparing left and right non-homologous regions, how can you interpret the differences between data?
We are looking for two things–what processing gives best discrimination and what does it mean. I’m not sure what it means if we have between region coherence analysis except I can “handwave” in that some coherence may indicate some level of network connection
Was there a notable difference in motion artifact content in concussion group? Relevant paper from Juliette Selb, motion/connectivty/stroke https://pubmed.ncbi.nlm.nih.gov/26018790/
Thanks, Meryem
no we didn’t notice that problem, thanks for the reference
Promising application! Looking at coherence seems a good way. Then, how do you deal with degree of concussion? Does it have influence on coherence?
Thanks for commenting. The degree of concussion is currently subjective and difficult to compare. We do collect symptom scores and relate results to them. Nothing in particular has jumped out yet. I’m hoping that we can argue that our results reflect a degree of severity.
Very interesting talk. Did you concussion patients have headache?
Thanks, yes, some had a headache. We do symptom assessment on all subjects before the study so we can relate results to symptoms. We were concerned that headache might make some patients stop the study. Nobody asked to stop though so the study didn’t seem to be a problem for them. The screens and the tests may be more of a problem than the headcap though
It might be interesting to stratify by presence of headache during scanning, since I would guess there’s a potential impact of the headache on coherence.
Hi Jana, Beautiful data! I have to ask about the dolphin imaging efforts. To what end? Thanks!
Thanks! The question is really whether we can reach the brain in dolphins with a NIRS device. There are many people involved, also trying to develop a suction cup design for mounting the NIRS. We are part of characterizing teh optical properties and modeling of diffusion through the thick blubber layer.
Great efforts! Concerning perfusion pressure, EEG signal seems more sensitive than fNIRS signal. Is it really the case?
Thanks for the question. The EEG signals have more features, but it really seems to be the case that the combination of the two is indicative of CPP.
congrats for your work. have you considered the different role that the sedatives may play in the results you showed?
Great question! We looked at different anesthetics and saw (as expected) that autoregulation is impaired when using isoflurane. But for the NVC work we only used fentanyl which leaves neuronal responses intact. So when considering patients, we will also need to evaluate different sedatives since they will have an influence in neuronal responses but we dont know yet how much and what influence.
Thank you for your talk! What operation was being done in the first slide that affected MAP/BFI/SO2 so much?
Interesting approach. How many wave length combinations are practically feasible?
We are currently simulating wavelengths between 600-980nm, in steps of 2nm, but will use 1nm resolution in our experimental validation. Thanks!
Great progress. I am a bit surprised to see infants’ auditory responses. Are they that rapid? Any developmental changes?
yes peak at 5 seconds, no change over 2-12 months
Hi Colette, Good to hear what you’re up to. I love the visual speech/occipital lobe data. How do you reconcile them with earlier arguments that crossmodal adjustments have negative implications for CI outcomes? Thanks!
some studies used pre-lingually deaf adults who have different plasticity effects than our post-lingually deaf participants
Did you consider laser-doppler for covid patients? A combination of perfusion and oxygenation in peripheral microcirculation?
We did not consider skin perfusion with LDF. I know it is possible and interesting to do so. VASCOVID project will introduce TRS + DCS to deal with that.
Very important application! Are CHD patients just slow in development? Or are they different in brain functions compared to control children?
Children with complex CHD may have slower development, leading to developmental delays, but also neurodevelopmental disabilities (e.g. Coordination Disorders, ADHD, learning disabilities…).
The brain of children with complex CHD also develop a bit differently. At birth, they have what we call the “preterm brain syndrome”. Although most of them are born at term, many babies have immature brains. Several studies showed altered structural and functional connectivity that persist at adolescence and adulthood. I can send you references if you are interested. Just send me an email.
fascinating talk. can you say more about the dissociation that you see between the EEG response and the fNIRS response in the infant with auditory neuropathy? what’s the explanation for this dissociation?
AN causes dis-synchrony of the neural response, so when many epochs are averaged in auditory brain response, the averaging makes the response disappear. fNIRS is not sensitive to neural synchrony only on the amount of activity so we can see the cortical response if the infant can hear the sound
Could you clarify what state the infants at each age are in during FC data collection? Sleep, visual stim? And I presume you are analyzing Oxy only?
Most studies are in infants in whom fNIRS data acquisition is done when they are asleep.
The data I showed in the presentation were HbO data, but we also look at HbR data in the analyses.
great talk! can you say more about how to map the language scores in the children with CHD with the FC? I didn’t catch how you did that analysis to pick out the connectivity analyses? Also are there general connectivity differences between the CHD and the controls?
So far, we are using correlations to look at the associations between the 4-month FC and 24-month neurodevelopment outcomes.
We are applying Phase coherence analyses for connectivity analyses.
Great projects! What language tests do you use with the epileptic patients to dissociate receptive from expressive? Thanks!
We use various tasks, but typically we use semantic verbal fluency task to localize expressive language and passive story listening task for receptive language. I can send you a paper explaining the task if you want.
really cool results. for the 2 TBI populations do you see differences in follow ups?
We haven’t done follow-ups. Good question. We are starting a study where we hope to get people at less than 7 days, then again at 1 and 3 months
Thank you very much for your great talk. I have a quick question about FC matrix. The correlation value looks a little bit lower than as usual for fNIRS. Whether the signals from all channels are good enough ?
Actually, we had a very good signal since the babies were sleeping :) and many of them didn’t have a lot of hair yet. The values may seems low, which is partly explained by the fact that in this study we used phase coherence analyses, not Pearson or Hilbert correlations.
What anesthesia did you use during the perfusion pressure studies–or was there anesthesia?
Great presentation, Collette. I have a question regarding habituation and novelty detection. Do you expect the novelty response to happen in a slightly different region than the first response to a stimuli? If you are really restricting the ROi to a few channels, would you expect the novelty response to happen on a neighbouring but slightly different ROI?
Good question! Yes there are slight differences but not much. The sleeping infant brain tends to have a spatially broad response, so we see a similar patterns across auditory and pre-frontal areas. Not so in awake adults