Browse publications by year: 2021

  1. De Silva L, Fu JY, Htar TT, Wan Kamal WHB, Kasbollah A, Muniyandy S, et al.
    Front Pharmacol, 2021;12:778396.
    PMID: 35069200 DOI: 10.3389/fphar.2021.778396
    The purpose of this work was to study the biodistribution of niosomes in tumor-implanted BALB/c mice using gamma scintigraphy. Niosomes were first formulated and characterized, then radiolabeled with Technetium-99 m (99mTc). The biodistribution of 99mTc-labeled niosomes was evaluated in tumor-bearing mice through intravenous injection and imaged with gamma scintigraphy. The labeled complexes possessed high radiolabeling efficiency (98.08%) and were stable in vitro (>80% after 8 h). Scintigraphic imaging showed negligible accumulation in the stomach and thyroid, indicating minimal leaching of the radiolabel in vivo. Radioactivity was found mainly in the liver, spleen and kidneys. Tumor-to-muscle ratio indicated a higher specificity of the formulation for the tumor area. Overall, the formulated niosomes are stable both in vitro and in vivo, and show preferential tumor accumulation.
  2. Nik Mohamed Kamal NNS, Shahidan WNS
    Front Physiol, 2021;12:798682.
    PMID: 35069258 DOI: 10.3389/fphys.2021.798682
    Periodontitis is a chronic inflammatory condition that causes tooth loss by destroying the supporting components of the teeth. In most cases, it is difficult to diagnose early and results in severe phases of the disease. Given their endogenous origins, exosomes, which are rich in peptides, lipids, and nucleic acids, have emerged as a cell-free therapeutic approach with low immunogenicity and increased safety. Because the constituents of exosomes can be reprogrammed depending on disease states, exosomes are increasingly being evaluated to act as potential diagnostic biomarkers for dental disease, including periodontitis. Exosomes also have been demonstrated to be involved in inflammatory signal transmission and periodontitis progression in vitro, indicating that they could be used as therapeutic targets for periodontal regeneration. Nevertheless, a review on the involvement of salivary exosomes in periodontitis in impacting the successful diagnosis and treatment of periodontitis is still lacking in the literature. Thus, this review is intended to scrutinize recent advancements of salivary exosomes in periodontitis treatment. We summarize recent research reports on the emerging roles and characteristics of salivary exosomes, emphasizing the different expressions and changed biological roles of exosomes in periodontitis.
  3. Lew B, Kõlves K, Lester D, Chen WS, Ibrahim NB, Khamal NRB, et al.
    Front Psychiatry, 2021;12:770252.
    PMID: 35069279 DOI: 10.3389/fpsyt.2021.770252
    Background: Suicide is a preventable cause of death. Examining suicide rates and trends are important in shaping national suicide prevention strategies. Therefore, the objectives of this study were to analyze age-standardized suicide trends of Malaysia between 2000 and 2019 using the WHO Global Health Estimates data, and to compare the 2019 rate with countries from the Association of South-East Asian Nations (ASEAN), Muslim majority countries, and the Group of Seven (G7). Methods: The age-standardized suicide rates data were extracted from the WHO Global Health Estimates. We calculated the average age-standardized suicide rates of the last 3 years from 2017 to 2019. Joinpoint regression analysis was conducted to calculate the average annual percentage change (APC) of the age-standardized suicide rates in Malaysia from 2000 to 2019. Results: Between 2000 and 2019, the minimum and maximum suicide rates for both sexes in Malaysia were 4.9 and 6.1 per 100,000 population respectively, whilst the past 3-year (2017-2019) average rates were 5.6, 8.8, and 2.4 for both sexes, males, and females, respectively. The suicide rates decreased significantly for both sexes between 2000 and 2013. Between 2014 and 2019, the suicide rates increased significantly for males. In 2019, Malaysia recorded the rate of 5.8 per 100,000 population, with an estimated 1,841 suicide deaths, i.e., ~5 deaths per day. The Malaysian suicide rate was the second highest amongst selected Muslim majority countries, in the middle range amongst ASEAN countries, and lower than all G7 countries except Italy. Conclusions: There is a need to further explore factors contributing to the higher suicide rates among Malaysian males. In light of the rising suicide rates in Malaysia, national mental health and suicide prevention initiatives are discussed and the importance of high-quality suicide surveillance data is emphasized.
  4. Siraji MA, Kalavally V, Schaefer A, Haque S
    Front Psychol, 2021;12:765750.
    PMID: 35069337 DOI: 10.3389/fpsyg.2021.765750
    This paper reports the results of a systematic review conducted on articles examining the effects of daytime electric light exposure on alertness and higher cognitive functions. For this, we selected 59 quantitative research articles from 11 online databases. The review protocol was registered with PROSPERO (CRD42020157603). The results showed that both short-wavelength dominant light exposure and higher intensity white light exposure induced alertness. However, those influences depended on factors like the participants' homeostatic sleep drive and the time of day the participants received the light exposure. The relationship between light exposure and higher cognitive functions was not as straightforward as the alerting effect. The optimal light property for higher cognitive functions was reported dependent on other factors, such as task complexity and properties of control light. Among the studies with short-wavelength dominant light exposure, ten studies (morning: 3; afternoon: 7) reported beneficial effects on simple task performances (reaction time), and four studies (morning: 3; afternoon: 1) on complex task performances. Four studies with higher intensity white light exposure (morning: 3; afternoon: 1) reported beneficial effects on simple task performance and nine studies (morning: 5; afternoon: 4) on complex task performance. Short-wavelength dominant light exposure with higher light intensity induced a beneficial effect on alertness and simple task performances. However, those effects did not hold for complex task performances. The results indicate the need for further studies to understand the influence of short-wavelength dominant light exposure with higher illuminance on alertness and higher cognitive functions.
  5. Lee WC, Shahari S, Nguee SYT, Lau YL, Rénia L
    Front Microbiol, 2021;12:804417.
    PMID: 35069511 DOI: 10.3389/fmicb.2021.804417
    Plasmodium knowlesi is responsible for zoonotic malaria infections that are potentially fatal. While the severe pathology of falciparum malaria is associated with cytoadherence phenomena by Plasmodium falciparum-infected erythrocytes (IRBC), information regarding cytoadherence properties of P. knowlesi-IRBC remained scarce. Here, we characterized the cytoadherence properties of RBC infected with the laboratory-adapted P. knowlesi A1-H.1 strain. We found that late-stage IRBC formed rosettes in a human serum-dependent manner, and rosettes hampered IRBC phagocytosis. IRBC did not adhere much to unexposed (unstimulated) human endothelial cell lines derived from the brain (hCMEC/D3), lungs (HPMEC), and kidneys (HRGEC). However, after being "primed" with P. knowlesi culture supernatant, the IRBC-endothelial cytoadherence rate increased in HPMEC and HRGEC, but not in hCMEC/D3 cells. Both endothelial cytoadherence and rosetting phenomena were abrogated by treatment of P. knowlesi-IRBC with trypsin. We also found that different receptors were involved in IRBC cytoadherence to different types of endothelial cells. Although some of the host receptors were shared by both P. falciparum- and P. knowlesi-IRBC, the availability of glycoconjugates on the receptors might influence the capacity of P. knowlesi-IRBC to cytoadhere to these receptors.
  6. Tan CH, Bourges A, Tan KY
    PMID: 35069710 DOI: 10.1590/1678-9199-JVATITD-2021-0051
    King Cobra (Ophiophagus hannah) has a significant place in many cultures, and is a medically important venomous snake in the world. Envenomation by this snake is highly lethal, manifested mainly by neurotoxicity and local tissue damage. King Cobra may be part of a larger species complex, and is widely distributed across Southeast Asia, southern China, northern and eastern regions as well as the Western Ghats of India, indicating potential geographical variation in venom composition. There is, however, only one species-specific King Cobra antivenom available worldwide that is produced in Thailand, using venom from the snake of Thai origin. Issues relating to the management of King Cobra envenomation (e.g., variation in the composition and toxicity of the venom, limited availability and efficacy of antivenom), and challenges faced in the research of venom (in particular proteomics), are rarely addressed. This article reviews the natural history and sociocultural importance of King Cobra, cases of snakebite envenomation caused by this species, current practice of management (preclinical and clinical), and major toxinological studies of the venom with a focus on venom proteomics, toxicity and neutralization. Unfortunately, epidemiological data of King Cobra bite is scarce, and venom proteomes reported in various studies revealed marked discrepancies in details. Challenges, such as inconsistency in snake venom sampling, varying methodology of proteomic analysis, lack of mechanistic and antivenomic studies, and controversy surrounding antivenom use in treating King Cobra envenomation are herein discussed. Future directions are proposed, including the effort to establish a standard, comprehensive Pan-Asian proteomic database of King Cobra venom, from which the venom variation can be determined. Research should be undertaken to characterize the toxin antigenicity, and to develop an antivenom with improved efficacy and wider geographical utility. The endeavors are aligned with the WHO´s roadmap that aims to reduce the disease burden of snakebite by 50% before 2030.
  7. Kaur H
    J Grad Med Educ, 2021 Dec;13(6):879-880.
    PMID: 35070103 DOI: 10.4300/JGME-D-21-00839.1
  8. Abd Hamid A, Zakaria N, Masnon NA, Muhammed J, Wan Hitam WH
    Cureus, 2021 Dec;13(12):e20513.
    PMID: 35070550 DOI: 10.7759/cureus.20513
    We describe a rare case of a patient with systemic lupus erythematosus (SLE) with functional visual loss (FVL). A 30-year-old female had blindness in the left eye due to multiple episodes of optic neuritis with underlying SLE. She presented with blurred vision in the right eye after an upper respiratory tract infection. The visual acuity in the right eye was 6/24, while the left eye had no light perception. The right eye optic nerve function tests were within normal limits. There was a positive relative afferent pupillary defect in the left eye. Fundoscopy showed left optic atrophy, while the right fundus was normal. The patient was treated according to a diagnosis of right retrobulbar optic neuritis. However, despite a course of intravenous methylprednisolone, her right visual acuity deteriorated to light perception. A magnetic resonance imaging (MRI) scan of the brain and orbit was normal. The visual evoked potential (VEP) in the right eye was also normal. The patient was suspected of having FVL and was referred to a psychiatrist. She was diagnosed with major depressive disorder after a full psychiatric assessment.
  9. Sohaimi NM, Hair-Bejo M
    Open Vet J, 2021 10 19;11(4):569-580.
    PMID: 35070851 DOI: 10.5455/OVJ.2021.v11.i4.6
    Fowl adenovirus (FAdV) is a double-stranded DNA virus with a non-enveloped structure comprising three major proteins known as hexon, penton, and fiber. Molecular analysis which emphasizes on hexon and fiber proteins is currently the major focus of curiosity for FAdV antigenicity and pathogenicity. Recently, disease outbreaks associated with FAdV infections such as inclusion body hepatitis, hepatitis hydropericardium syndrome, and gizzard erosion, were commonly reported and continue to increase worldwide. Studies on the virulence gene of the virus were intensively conducted to provide a better understanding on the role of these major capsid proteins in the development of a safe and effective vaccine against the disease in the poultry industry. This paper highlights the variations of the fiber and hexon genes, their importance in genotypes and serotypes differentiation, and infectivity between FAdV strains. It appears that the L1 loop of hexon and the knob of fiber genes are the infectivity markers for FAdV infection. The fiber-2 protein plays a major role in FAdV pathogenicity than the hexon protein, while the fiber-1 protein is important for viral replication and assembly, regardless of virulence capability instead of infectivity. The hexon protein plays a major role in virus infectivity and tissue tropism. These findings could further enhance the knowledge of FAdV strains' classification and evolution, diagnosis, and strategies to prevent and control FAdV infection and outbreaks in chicken farms.
  10. Yiek SH
    Asian J Neurosurg, 2021 12 18;16(4):899-901.
    PMID: 35071099 DOI: 10.4103/ajns.AJNS_269_21
    Fibromuscular dysplasia (FMD) is an idiopathic, non-inflammatory, and non-atherosclerotic vascular disease of small- to medium-sized arteries. It can be occurred in almost all arteries and most commonly involving cervicocranial and renal arteries. FMD is commonly present as renovascular hypertension and affecting most young ladies. However, this case demonstrates a casuistically rare form of multiple arterial beds involvement at different sites, i.e. vertebral, coronary, hepatic, and lumbar arteries, with the conjunction of both bilateral renal and cervicocranial arteries.
  11. Muhardi L, Aw MM, Hasosah M, Ng RT, Chong SY, Hegar B, et al.
    Front Pediatr, 2021;9:778747.
    PMID: 35071132 DOI: 10.3389/fped.2021.778747
    Regurgitation, colic, and constipation are frequently reported Functional Gastrointestinal Disorders (FGIDs) in the first few years of life. In 2016, the diagnostic criteria for FGIDs were changed from ROME III to ROME IV. This review assesses the prevalence of the most frequent FGIDs (colic, regurgitation and constipation) among children aged 0-5 years after the introduction of the later criteria. Articles published from January 1, 2016 to May 1, 2021 were retrieved from PubMed and Google Scholar using relevant keywords. A total of 12 articles were further analyzed based on the inclusion and exclusion criteria. This review consists of two studies (17%) from the Middle East, three (25%) from Asia, two (17%) from the USA, three (25%) from Europe, and one (8%) from Africa. Three studies (25%) were based on data obtained from healthcare professionals, while the rest were parent or caregiver reports. About half of the retrieved studies used the ROME IV criteria. Among infants aged 0-6 months, the reported prevalence of colic ranged between 10-15%, whilst that of regurgitation was 33.9%, and constipation was 1.5%. Among infants aged 0-12 months, the reported prevalence of regurgitation and constipation were 3.4-25.9% and 1.3-17.7%, respectively. The reported prevalence of constipation was 1.3-26% among children aged 13-48 months and 13% among children aged 4-18 years. Despite the large variations due to differences in diagnostic criteria, study respondents and age group, the prevalence of infantile colic was higher, while that for infantile regurgitation and constipation were similar using the ROME IV or III criteria.
  12. Talia KL, Rahimi S, Hawkes D, McCluggage WG
    Int J Gynecol Pathol, 2021 Nov 12.
    PMID: 35072991 DOI: 10.1097/PGP.0000000000000835
    Seborrheic keratosis-like lesion (SKLL) is an extremely rare, morphologically distinct lesion occurring in the cervix and vagina that differs histologically from usual squamous intraepithelial lesions in these sites, by bearing close resemblance to cutaneous seborrheic keratosis and lacking koilocytosis. Like many vulvar seborrheic keratoses, which are associated with low-risk human papillomavirus (HPV), an association between SKLL and low-risk HPV is suggested based on the identification of HPV42, regarded as a low-risk genotype, in 4 of 8 reported cases. We report a further HPV42-associated SKLL of the cervix which differs from the previously reported cases by the presence of high-grade morphology and block-type p16 immunoreactivity. This novel finding challenges the classification of HPV42 as a low-risk genotype and expands the reported morphologic spectrum of SKLL, suggesting that they may not always be clinically indolent.
  13. Mohd Faizal MN, Ismail N, M S Eldeen I, Mariam T
    Pak J Biol Sci, 2021 Jan;24(5):579-587.
    PMID: 34486333 DOI: 10.3923/pjbs.2021.579.587
    <b>Background and Objective:</b> Horseshoe crabs are widely used in both traditional and modern pharmaceutical applications. Most of the previous studies on horseshoe crabs focused on their blood which contains hemolymph and amoebocyte lysate. This study aimed to determine the potential antibacterial and antifouling properties of different extracts from the carapace and the book gills of <i>Carcinoscorpius rotundicauda</i>. <b>Materials and Methods:</b> The crude extracts were subjected to the bioactivity tests using the disc-diffusion and the inhibition of biofilm-formation measurement assays, for both the antibacterial and antifouling activities respectively. <b>Results:</b> The results obtained indicated that the carapace extracts had stronger antibacterial and antifouling effects compared to the book gills extracts. Extracts obtained from the male displayed more activity compared to the extracts from the female with a few exceptions. Methanol and acetone carapace crude extracts showed the best overall performance. A sterol compound was isolated from the carapace acetone extracts of the male of <i>C. rotundicauda</i>. However, the compound did not display strong activity compared to the crude extract. The compound might be contributing to the observed activity with other components through a synergistic effect. <b>Conclusion:</b> The presence of antibacterial and antifouling activities in the carapace and book gills extracts could be added to the complexity of the defence mechanisms of horseshoe crabs. The results of this study, therefore, may contribute to the knowledge of the defence mechanisms of <i>C. rotundicauda</i>. Further research is needed to determine the bioactivities of other parts of the animal and to explore their potential applications.
    MeSH terms: Animals; Anti-Bacterial Agents/pharmacology; Anti-Bacterial Agents/therapeutic use; Biological Assay/methods; Horseshoe Crabs/enzymology*; Malaysia; Microbial Sensitivity Tests/methods; Complex Mixtures/pharmacology*; Complex Mixtures/therapeutic use
  14. You YX, Shahar S, Mohamad M, Rajab NF, Che Din N, Lau HJ, et al.
    Front Hum Neurosci, 2021;15:765451.
    PMID: 35046782 DOI: 10.3389/fnhum.2021.765451
    Working memory is developed in one region of the brain called the dorsolateral prefrontal cortex (DLPFC). The dysfunction of this region leads to synaptic neuroplasticity impairment. It has been reported that several biochemical parameters and anthropometric measurements play a vital role in cognition and brain health. This study aimed to investigate the relationships between cognitive function, serum biochemical profile, and anthropometric measurements using DLPFC activation. A cross-sectional study was conducted among 35 older adults (≥60 years) who experienced mild cognitive impairment (MCI). For this purpose, we distributed a comprehensive interview-based questionnaire for collecting sociodemographic information from the participants and conducting cognitive tests. Anthropometric values were measured, and fasting blood specimens were collected. We investigated their brain activation using the task-based functional MRI (fMRI; N-back), specifically in the DLPFC region. Positive relationships were observed between brain-derived neurotrophic factor (BDNF) (β = 0.494, p < 0.01) and Mini-Mental State Examination (MMSE) (β = 0.698, p < 0.01); however, negative relationships were observed between serum triglyceride (β = -0.402, p < 0.05) and serum malondialdehyde (MDA) (β = -0.326, p < 0.05) with right DLPFC activation (R 2 = 0.512) while the participants performed 1-back task after adjustments for age, gender, and years of education. In conclusion, higher serum triglycerides, higher oxidative stress, and lower neurotrophic factor were associated with lower right DLPFC activation among older adults with MCI. A further investigation needs to be carried out to understand the causal-effect mechanisms of the significant parameters and the DLPFC activation so that better intervention strategies can be developed for reducing the risk of irreversible neurodegenerative diseases among older adults with MCI.
  15. Abd Rahman FN, Wong YY, Khalib AQ
    Front Psychiatry, 2021;12:772744.
    PMID: 35046852 DOI: 10.3389/fpsyt.2021.772744
    Postnatal depression is a major illness affecting maternal and family health. The rate of postnatal depression among mental health clients is postulated to be higher than in the community due to the added brain assault. Children of parents who are mental health clients are more likely to have psychological problems compared to children from other parents in the community. This study investigates the rate of postnatal depression among mental health clients and their offspring's psychological health. A total of 140 mental health clients were assessed using the Edinburgh Postnatal Depression Scale (EPDS). They subsequently completed the Strength and Difficulties Questionnaire (SDQ) regarding their children. The majority ethnicity was the Kadazan (40.7%). The mean age of mothers was 38.6 (7) years with most having a secondary education (53.6%) and a household income per month of < RM1000 per month (27.1%). The postnatal depression rate was 47.8%. Higher EPDS scores were associated with higher total SDQ scores in their offspring. Model 1 was unadjusted, giving an OR of 5.65 [95% CI (3.74, 7.55)], p < 0.001. After adjustment for confounders, Model 2 had an OR of 5.51 [95% CI (3.57, 7.46)], p < 0.001. More efforts need to be given to the early detection of maternal depression and its prompt treatment in mental health clients because of the relationship with the psychological health of the offspring.
  16. Li H, Tang R, Mustapha WAW, Liu J, Hasan KMF, Li X, et al.
    Gels, 2021 Dec 27;8(1).
    PMID: 35049558 DOI: 10.3390/gels8010021
    Gelatin coating is an effective way to prolong the shelf life of meat products. Aiming at solving the problem of flavor deterioration during the storage of pork at room temperature, pork coating technology was developed to preserve the pork at 25 °C, and the comprehensive sensory analysis of vision, touch, smell, and taste was used to study the effect of coating on preservation of pork flavor. Herein, uncoated (control) and coated pork samples (including gelatin coating and gelatin coating incorporated with ginger essential oil) were analyzed to investigate the integrity of pork periodically during storage at 25 °C for weight loss, color, texture (springiness, chewiness, cohesiveness, gumminess, and hardness), microstructure, odor (electronic nose), taste (electronic tongue), volatile flavor substance, and taste ingredients. The results suggested that ginger essential oil (GEO) gelatin coating and gelatin coating can effectively inhibit the loss of water dispersion and slow down the oxidation reaction, coating treatments could significantly (p < 0.05) retarded the weight loss of pork slices, with values of 20.19%, 15.95%, 13.12% for uncoated, gelatin coated, and GEO-gelatin coated samples during 24 h of storage, respectively. Compared with control group, the color, texture, smell, and taste evaluations demonstrated that coating treatments had improved sensory and texture attributes during the storage period. Furthermore, the comprehensive results from the physical property assays (especially the texture), morphological assay and volatile odor assays showed that the GEO-fish gelatin composite coating had better preservation effect on pork flavor than the fish gelatin coating. The study suggests that the gelatin composite coating could be developed as a prospective active packaging to preserve pork meat at room temperature.
  17. Ab Rhaman SMS, Naher L, Siddiquee S
    J Fungi (Basel), 2021 Dec 31;8(1).
    PMID: 35049981 DOI: 10.3390/jof8010042
    Mushrooms are popular due to the nutrition contents in the fruit bodies and are relatively easy to cultivate. Mushrooms from the white-rot fungi group can be cultivated on agricultural biomass such as sawdust, paddy straw, wheat straw, oil palm frond, oil palm empty fruit bunches, oil palm bark, corn silage, corn cobs, banana leaves, coconut husk, pineapple peel, pineapple leaves, cotton stalk, sugarcane bagasse and various other agricultural biomass. Mushrooms are exceptional decomposers that play important roles in the food web to balance the ecosystems. They can uptake various minerals, including essential and non-essential minerals provided by the substrates. However, the agricultural biomass used for mushroom cultivation is sometimes polluted by heavy metals because of the increased anthropogenic activities occurring in line with urbanisation. Due to their role in mycoremediation, the mushrooms also absorb pollutants from the substrates into their fruit bodies. This article reviews the sources of agricultural biomass for mushroom cultivation that could track how the environmental heavy metals are accumulated and translocated into mushroom fruit bodies. This review also discusses the possible health risks from prolonged uptakes of heavy metal-contaminated mushrooms to highlight the importance of early contaminants' detection for food security.
  18. Dalolio M, Cordier D, Al-Zahid S, Bennett WO, Prepageran N, Waran V, et al.
    J Craniofac Surg, 2021 Oct 12.
    PMID: 35050560 DOI: 10.1097/SCS.0000000000008204
    Objectives: Information about the endonasal endoscopic approach (EEA) for the management of posttraumatic tension pneumocephalus (PTTP) remains scarce. Concomitant rhinoliquorrhea and posttraumatic hydrocephalus (PTH) can complicate the clinical course.

    Methods: The authors systematically reviewed pertinent articles published between 1961 and December 2020 and identified 6 patients with PTTP treated by EEA in 5 reports. Additionally, the authors share their institutional experience including a seventh patient, where an EEA resolved a recurrent PTTP without rhinoliquorrhea.

    Results: Seven PTTP cases in which EEA was used as part of the treatment regime were included in this review. All cases presented with a defect in the anterior skull base, and 3 of them had concomitant rhinoliquorrhea. A transcranial approach was performed in 6/7 cases before EEA was considered to treat PTTP. In 4/7 cases, the PTTP resolved after the first intent; in 2/7 cases a second repair was necessary because of recurrent PTTP, 1 with and 1 without rhinoliquorrhea, and 1/7 case because of recurrent rhinoliquorrhea only. Overall, PTTP treated by EEA resolved with a mean radiological resolution time of 69 days (range 23-150 days), with no late recurrences. Only 1 patient developed a cerebrospinal fluid diversion infection probably related to a first incomplete EEA skull base defects repair. A permanent cerebrospinal fluid diversion was necessary in 3/7 cases.

    Conclusions: Endonasal endoscopic approach repair of air conduits is a safe and efficacious second-line approach after failed transcranial approaches for symptomatic PTTP. However, the strength of recommendation for EEA remains low until further evidence is presented.

  19. Wen D, Li R, Jiang M, Li J, Liu Y, Dong X, et al.
    Neural Netw, 2021 Dec 25;148:23-36.
    PMID: 35051867 DOI: 10.1016/j.neunet.2021.12.010
    This study aims to explore an effective method to evaluate spatial cognitive ability, which can effectively extract and classify the feature of EEG signals collected from subjects participating in the virtual reality (VR) environment; and evaluate the training effect objectively and quantitatively to ensure the objectivity and accuracy of spatial cognition evaluation, according to the classification results. Therefore, a multi-dimensional conditional mutual information (MCMI) method is proposed, which could calculate the coupling strength of two channels considering the influence of other channels. The coupled characteristics of the multi-frequency combination were transformed into multi-spectral images, and the image data were classified employing the convolutional neural networks (CNN) model. The experimental results showed that the multi-spectral image transform features based on MCMI are better in classification than other methods, and among the classification results of six band combinations, the best classification accuracy of Beta1-Beta2-Gamma combination is 98.3%. The MCMI characteristics on the Beta1-Beta2-Gamma band combination can be a biological marker for the evaluation of spatial cognition. The proposed feature extraction method based on MCMI provides a new perspective for spatial cognitive ability assessment and analysis.
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