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Visual brain activity patterns classification with simultaneous EEG-fMRI: A multimodal approach

Ahmad RF, Malik AS, Kamel N, Reza F, Amin HU, Hussain M

Technol Health Care, 2017;25(3):471-485.
PMID: 27935575 DOI: 10.3233/THC-161286

BACKGROUND: Classification of the visual information from the brain activity data is a challenging task. Many studies reported in the literature are based on the brain activity patterns using either fMRI or EEG/MEG only. EEG and fMRI considered as two complementary neuroimaging modalities in terms of their temporal and spatial resolution to map the brain activity. For getting a high spatial and temporal resolution of the brain at the same time, simultaneous EEG-fMRI seems to be fruitful.
METHODS: In this article, we propose a new method based on simultaneous EEG-fMRI data and machine learning approach to classify the visual brain activity patterns. We acquired EEG-fMRI data simultaneously on the ten healthy human participants by showing them visual stimuli. Data fusion approach is used to merge EEG and fMRI data. Machine learning classifier is used for the classification purposes.
RESULTS: Results showed that superior classification performance has been achieved with simultaneous EEG-fMRI data as compared to the EEG and fMRI data standalone. This shows that multimodal approach improved the classification accuracy results as compared with other approaches reported in the literature.
CONCLUSIONS: The proposed simultaneous EEG-fMRI approach for classifying the brain activity patterns can be helpful to predict or fully decode the brain activity patterns.

Matched MeSH terms: Functional Neuroimaging/methods*
Fulltext Covert Cognition in Disorders of Consciousness: A Meta-Analysis

Schnakers C, Hirsch M, Noé E, Llorens R, Lejeune N, Veeramuthu V, et al.

Brain Sci, 2020 Dec 02;10(12).
PMID: 33276451 DOI: 10.3390/brainsci10120930

Covert cognition in patients with disorders of consciousness represents a real diagnostic conundrum for clinicians. In this meta-analysis, our main objective was to identify clinical and demographic variables that are more likely to be associated with responding to an active paradigm. Among 2018 citations found on PubMed, 60 observational studies were found relevant. Based on the QUADAS-2, 49 studies were considered. Data from 25 publications were extracted and included in the meta-analysis. Most of these studies used electrophysiology as well as counting tasks or mental imagery. According to our statistical analysis, patients clinically diagnosed as being in a vegetative state and in a minimally conscious state minus (MCS-) show similar likelihood in responding to active paradigm and responders are most likely suffering from a traumatic brain injury. In the future, multi-centric studies should be performed in order to increase sample size, with similar methodologies and include structural and functional neuroimaging in order to identify cerebral markers related to such a challenging diagnosis.

Matched MeSH terms: Functional Neuroimaging
Fulltext Neural oscillation, network, eloquent cortex and epileptogenic zone revealed by magnetoencephalography and awake craniotomy

Idris Z, Kandasamy R, Reza F, Abdullah JM

Asian J Neurosurg, 2014 Jul-Sep;9(3):144-52.
PMID: 25685205 DOI: 10.4103/1793-5482.142734

BACKGROUND: Magnetoencephalography (MEG) is a method of functional neuroimaging. The concomitant use of MEG and electrocorticography has been found to be useful in elucidating neural oscillation and network, and to localize epileptogenic zone and functional cortex. We describe our early experience using MEG in neurosurgical patients, emphasizing on its impact on patient management as well as the enrichment of our knowledge in neurosciences.
MATERIALS AND METHODS: A total of 10 subjects were included; five patients had intraaxial tumors, one with an extraaxial tumor and brain compression, two with arteriovenous malformations, one with cerebral peduncle hemorrhage and one with sensorimotor cortical dysplasia. All patients underwent evoked and spontaneous MEG recordings. MEG data was processed at band-pass filtering frequency of between 0.1 and 300 Hz with a sampling rate of 1 kHz. MEG source localization was performed using either overdetermined equivalent current dipoles or underdetermined inversed solution. Neuromag collection of events software was used to study brain network and epileptogenic zone. The studied data were analyzed for neural oscillation in three patients; brain network and clinical manifestation in five patients; and for the location of epileptogenic zone and eloquent cortex in two patients.
RESULTS: We elucidated neural oscillation in three patients. One demonstrated oscillatory phenomenon on stimulation of the motor-cortex during awake surgery, and two had improvement in neural oscillatory parameters after surgery. Brain networks corresponding to clinico-anatomical relationships were depicted in five patients, and two networks were illustrated here. Finally, we demonstrated epilepsy cases in which MEG data was found to be useful in localizing the epileptogenic zones and functional cortices.
CONCLUSION: The application of MEG while enhancing our knowledge in neurosciences also has a useful role in epilepsy and awake surgery.
KEYWORDS: Awake craniotomy; brain network; epilepsy; magnetoencephalography; neural oscillation

Matched MeSH terms: Functional Neuroimaging
Fulltext The association between subcortical and cortical fMRI and lifetime noise exposure in listeners with normal hearing thresholds

Dewey RS, Francis ST, Guest H, Prendergast G, Millman RE, Plack CJ, et al.

Neuroimage, 2020 01 01;204:116239.
PMID: 31586673 DOI: 10.1016/j.neuroimage.2019.116239

In animal models, exposure to high noise levels can cause permanent damage to hair-cell synapses (cochlear synaptopathy) for high-threshold auditory nerve fibers without affecting sensitivity to quiet sounds. This has been confirmed in several mammalian species, but the hypothesis that lifetime noise exposure affects auditory function in humans with normal audiometric thresholds remains unconfirmed and current evidence from human electrophysiology is contradictory. Here we report the auditory brainstem response (ABR), and both transient (stimulus onset and offset) and sustained functional magnetic resonance imaging (fMRI) responses throughout the human central auditory pathway across lifetime noise exposure. Healthy young individuals aged 25-40 years were recruited into high (n = 32) and low (n = 30) lifetime noise exposure groups, stratified for age, and balanced for audiometric threshold up to 16 kHz fMRI demonstrated robust broadband noise-related activity throughout the auditory pathway (cochlear nucleus, superior olivary complex, nucleus of the lateral lemniscus, inferior colliculus, medial geniculate body and auditory cortex). fMRI responses in the auditory pathway to broadband noise onset were significantly enhanced in the high noise exposure group relative to the low exposure group, differences in sustained fMRI responses did not reach significance, and no significant group differences were found in the click-evoked ABR. Exploratory analyses found no significant relationships between the neural responses and self-reported tinnitus or reduced sound-level tolerance (symptoms associated with synaptopathy). In summary, although a small effect, these fMRI results suggest that lifetime noise exposure may be associated with central hyperactivity in young adults with normal hearing thresholds.

Matched MeSH terms: Functional Neuroimaging*
Functional brain imaging of walking while talking - An fNIRS study

Metzger FG, Ehlis AC, Haeussinger FB, Schneeweiss P, Hudak J, Fallgatter AJ, et al.

Neuroscience, 2017 02 20;343:85-93.
PMID: 27915210 DOI: 10.1016/j.neuroscience.2016.11.032

Since functional imaging of whole body movements is not feasible with functional magnetic resonance imaging (fMRI), the present study presents in vivo functional near-infrared spectroscopy (fNIRS) as a suitable technique to measure body movement effects on fronto-temporo-parietal cortical activation in single- and dual-task paradigms. Previous fNIRS applications in studies addressing whole body movements were typically limited to the assessment of prefrontal brain areas. The current study investigated brain activation in the frontal, temporal and parietal cortex of both hemispheres using functional near-infrared spectroscopy (fNIRS) with two large 4×4 probe-sets with 24 channels each during single and dual gait tasks. 12 young healthy adults were measured using fNIRS walking on a treadmill: the participants performed two single-task (ST) paradigms (walking at different speeds, i.e. 3 and 5km/h) and a dual task (DT) paradigm where a verbal fluency task (VFT) had to be executed while walking at 3km/h. The results show an increase of activation in Broca's area during the more advanced conditions (ST 5km/h vs. ST 3km/h, DT vs. ST 3km/h, DT vs. 5km/h), while the corresponding area on the right hemisphere was also activated. DT paradigms including a cognitive task in conjunction with whole body movements elicit wide-spread cortical activation patterns across fronto-temporo-parietal areas. An elaborate assessment of these activation patterns requires more extensive fNIRS assessments than the traditional prefrontal investigations, e.g. as performed with portable fNIRS devices.

Matched MeSH terms: Functional Neuroimaging
Chronic neuronopathic type of Gaucher's disease with progressive myoclonic epilepsy in the absence of visceromegaly and bone involvement

Botross NP, Riad AA, Viswanathan S, Nordin RB, Lock HN

Scott Med J, 2014 May;59(2):e1-6.
PMID: 24671628 DOI: 10.1177/0036933014529868

Gaucher's disease is a lysosomal storage disorder caused by the deficiency of glucocerebrosidase. Gaucher's disease has three clinical types: non-neuronopathic (Type 1), Acute Neuropathic (Type 2) and chronic neuronopathic (Type 3). The chronic neuronopathic (Type 3) is characterised by a variety of disease variants with onset in childhood with hepatomegaly, skeletal lesions and later slow horizontal saccades, treatment-resistant generalised tonic-clonic and myoclonic seizures, dementia, progressive spasticity, cognitive deterioration, ataxia and death in the second or third decade of life.

Matched MeSH terms: Functional Neuroimaging