Probing depression, schizophrenia, and other psychiatric disorders using fNIRS and the verbal fluency test: A systematic review and meta-analysis

Identifying neuroimaging biomarkers in major depressive disorder using machine learning algorithms and functional near-infrared spectroscopy (fNIRS) during verbal fluency task

One of the most prevalent psychiatric disorders is major depressive disorder (MDD), which increases the probability of suicidal ideation or untimely demise. Abnormal frontal hemodynamic changes detected by functional near-infrared spectroscopy (fNIRS) during verbal fluency task (VFT) have the potential to be used as an objective indicator for assessing clinical symptoms. However, comprehensive quantitative and objective assessment instruments for individuals who exhibit symptoms suggestive of depression remain undeveloped. Drawing from a total of 467 samples in a large-scale dataset comprising 289 MDD patients and 178 healthy controls, fNIRS measurements were obtained throughout the VFT. To identify unique MDD biomarkers, this research introduced a data representation approach for extracting spatiotemporal features from fNIRS signals, which were subsequently utilized as potential predictors. Machine learning classifiers (e.g., Gradient Boosted Decision Trees (GBDT) and Multilayer Perceptron) were implemented to assess the ability to predict selected features. The mean and standard deviation of the cross-validation indicated that the GBDT model, when combined with the 180-feature pattern, distinguishes patients with MDD from healthy controls in the most effective manner. The accuracy of correct classification for the test set was 0.829 ± 0.053, with an AUC of 0.895 (95 % CI: 0.864-0.925) and a sensitivity of 0.914 ± 0.051. Channels that made the most important contribution to the identification of MDD were identified using Shapley Additive Explanations method, located in the frontopolar area and the dorsolateral prefrontal cortex, as well as pars triangularis Broca's area. Assessment of abnormal prefrontal activity during the VFT in MDD serves as an objectively measurable biomarker that could be utilized to evaluate cognitive deficits and facilitate early screening for MDD. The model suggested in this research could be applied to large-scale case-control fNIRS datasets to detect unique characteristics of MDD and offer clinicians an objective biomarker-based analytical instrument to assist in the evaluation of suspicious cases.

Habituation of Brain Activity with Repetition in Color and Picture-Word Stroop Tests

As a widely used mental task for functional near-infrared spectroscopy (fNIRS), the original color-word Stroop task has the advantage of being difficult to habituate, but also the disadvantage of being difficult to understand, especially for children. While the introduction of derived Stroop tasks offers highly promising countermeasures, changes in brain activity during these tests have not been well tested. We investigated the degree of habituation between the original and a derived Stroop task by measuring brain activity to obtain a better fNIRS task design. Fourteen healthy adults participated in the study, and a 10-channel fNIRS device was used. A picture-word Stroop task with lower linguistic conflict than the original was conducted. The original and derived Stroop tests were repeated four times in a 1-week interval. We found that the original Stroop test did not show any significant changes in brain activity with repeated measures; however, brain activity decreased during the derived test. The differences in habituation between the original and derived tests may be due to the differences in the strength of the linguistic conflict. Our findings also highlight the need to consider the effects of habituation when using derived Stroop tasks in repeated measures.

Prefrontal brain activity and self-injurious behavior in adolescents with major depressive disorder: A functional near-infrared spectroscopy (fNIRS) study

In clinical practice, accurately identifying self-injurious behavior among adolescents with major depressive disorder (MDD) is crucial for individualized treatment. This study aimed to examine the differences in prefrontal cortex activation using the functional near-infrared spectroscopy (fNIRS) during the verbal fluency task (VFT) assessment of adolescents with MDD and self-harm (SH) compared with those without SH. A total of 60 eligible patients were included for final analysis, with the SH group containing 36 participants, and the Non-SH group containing 24 participants. We found that right middle frontal gyrus (rMFG) was more activated in the SH group than that in the Non-SH group during the VFT assessments (z = -3.591, p = 0.004, FDR correction). The z-scores of beta values of rMFG exhibited a good discriminatory power with the area under the curve (AUC) in distinguishing the two groups (AUC = 0.775, p < 0.001). These findings reveal that the fNIRS-VFT paradigm may be a useful tool for discovering neurobiological differences among adolescents with MDD.

Anxiety symptoms without depression are associated with cognitive control network (CNN) dysfunction: An fNIRS study

Anxiety is a common psychological disorder associated with other mental disorders, with depression being the most common comorbidity. Few studies have examined the neural mechanisms underlying anxiety after controlling for depression. This study aimed to explore whether there are differences in cortical activation in anxiety patients with different severities whose depression are normal. In the current study, depression levels were normal for 366 subjects-139 healthy subjects, 117 with mild anxiety, and 110 with major anxiety. Using the Hospital Anxiety and Depression Scale (HADS) and a verbal fluency task (VFT) to test subjects' anxiety and depression and cognitive function, respectively. A 53-channel guided near-infrared spectroscopic imaging technology (fNIRS) detected the concentration of oxyhemoglobin (oxy-Hb). Correlation analysis between anxiety severity and oxy-Hb concentration in the brain cortex was performed, as well as ANOVA analysis of oxy-Hb concentration among the three anxiety severity groups. The results showed that anxiety severity was significantly and negatively correlated with oxy-Hb concentrations in the left frontal eye field (lFEF) and in the right dorsolateral prefrontal area (rDLPFC). The oxy-Hb concentration in the lFEF and the rDLPFC were significantly lower in the major anxiety disorder group than that in the control group. This suggests that decreased cortical activity of the lFEF and rDLPFC may be neural markers of anxiety symptoms after controlling for depression. Anxiety symptoms without depression may be result from the dysfunction of the cognitive control network (CCN) which includes the lFEF and rDLPFC.

An automated ensemble approach using Harris Hawk optimization for visually evoked EEG signal classification

Steady-state visually evoked potential is one of the active explorations in the brain-computer interface research. Electroencephalogram based brain computer interface studies have been widely applied to perceive solutions for real-world problems in the healthcare domain. The classification of externally bestowed visual stimuli of different frequencies on a human was experimented to identify the need of paralytic people. Although many classifiers are at the fingertip of machine learning technology, recent research has proven that ensemble learning is more efficacious than individual classifiers. Despite its efficiency, ensemble learning technology exhibits certain drawbacks like taking more time on selecting the optimal classifier subset. This research article utilizes the Harris Hawk Optimization algorithm to select the best classifier subset from the given set of classifiers. The objective of the research is to develop an efficient multi-classifier model for electroencephalogram signal classification. The proposed model utilizes the Boruta Feature Selection algorithm to select the prominent features for classification. Thus selected prominent features are fed into the multi-classifier subset which has been generated by the Harris Hawk Optimization algorithm. The results of the multi-classifier ensemble model are aggregated using Stacking, Bagging, Boosting, and Voting. The proposed model is evaluated against the acquired dataset and produces a promising accuracy of 96.1%, 98.7%, 91.91%, and 99.01% with the ensemble techniques respectively. The proposed model is also validated with other performance metrics such as sensitivity, specificity, and F1-Score. The experimental results show that the proposed model proves its supremacy in segregating the multi-class classification problem with high accuracy.

A scoping review of functional near-infrared spectroscopy biomarkers in late-life depression: Depressive symptoms, cognitive functioning, and social functioning

Late-life depression is one of the most damaging mental illnesses, disrupting the normal lives of older people by causing chronic illness and cognitive impairment. Patients with late-life depression, accompanied by changes in appetite, insomnia, fatigue and guilt, are more likely to experience irritability, anxiety and somatic symptoms. It increases the risk of suicide and dementia and is a major challenge for the public health systems. The current clinical assessment, identification and effectiveness assessment of late-life depression are primarily based on history taking, mental status examination and scale scoring, which lack subjectivity and precision. Functional near-infrared spectroscopy is a rapidly developing optical imaging technology that objectively reflects the oxygenation of hemoglobin in different cerebral regions during different tasks and assesses the functional status of the cerebral cortex. This article presents a comprehensive review of the assessment of functional near-infrared spectroscopy technology in assessing depressive symptoms, social functioning, and cognitive functioning in patients with late-life depression. The use of functional near-infrared spectroscopy provides greater insight into the neurobiological mechanisms underlying depression and helps to assess these three aspects of functionality in depressed patients. In addition, the study discusses the limitations of previous research and explores potential advances in the field.

Characteristics of oxyhemoglobin during the verbal fluency task in subthreshold depression: A multi-channel near-infrared spectroscopy study

OBJECTIVE

Subthreshold depression is an essential precursor and risk factor for major depressive disorder, and its accurate identification and timely intervention are important for reducing the prevalence of major depressive disorder. Therefore, we used functional near-infrared spectroscopic imaging (fNIRS) to explore the characteristics of the brain neural activity of college students with subthreshold depression in the verbal fluency task.

METHODS

A total of 72 subthreshold depressed college students (SDs) and 67 healthy college students (HCs) were recruited, and all subjects were subjected to a verbal fluency task (VFT) while a 53-channel fNIRS device was used to collect the subjects' cerebral blood oxygenation signals.

RESULTS

The results of the independent samples t-test showed that the mean oxyhemoglobin in the right dorsolateral prefrontal (ch34, ch42, ch45) and Broca's area (ch51, ch53) of SDs was lower than that of HCs. The peak oxygenated hemoglobin of SDs was lower in the right dorsolateral prefrontal (ch34) and Broca's area (ch51, ch53).The brain functional connectivity strength was lower than that of HCs. Correlation analysis showed that the left DLPFC and Broca's area were significantly negatively correlated with the depression level.

CONCLUSION

SDs showed abnormally low, inadequate levels of brain activation and weak frontotemporal brain functional connectivity. The right DLPFC has a higher sensitivity for the differentiation of depressive symptoms and is suitable as a biomarker for the presence of depressive symptoms. Dysfunction in Broca's area can be used both as a marker of depressive symptoms and as a biomarker, indicating the severity of depressive symptoms.

Cortical activation for adolescent-onset minor depression and major depressive disorder: an fNIRS study

BACKGROUND

While depression is increasing worldwide, some patients are diagnosed as having Major Depressive Disorder (MDD), but others are diagnosed with minor depression, however, the potential neuro mechanism is unknown.

METHODS

Sixty-two patients with minor depression, 44 adolescents with MDD and 54 healthy adolescents participated in this study. Functional near-infrared spectroscopy (fNIRS), both HAMD and HAMA data were collected from all of the participants.

RESULTS

The result indicates the pervasively decreased activation of BA, 11, 21, 45 and 46 were observed in the MDD group and reduced activation of BA 45 was observed in the minor depression group. However, cortical activation was not observed between the minor depression or MDD groups. Cortical activation was also not correlated with the depressive/anxious score in the minor and MDD groups separately.

CONCLUSIONS

Cortical activation was pervasively decreased in the MDD group and slightly reduced in the minor depression group, which may be a potential neural mechanism. As reduced cortical activation in minor depression, interventions in the early stages of minor depression may help slow or even modify the development of the illness.

Reduced inhibition control ability in children with ADHD due to coexisting learning disorders: an fNIRS study

Introduction

Inhibition control, as the core component of executive function, might play a crucial role in the understanding of attention deficit/hyperactivity disorder (ADHD) and specific learning disorders (SLD). Inhibition control deficits have been observed in children with ADHD or SLD. This study sought to test in a multi-modal fashion (i.e., behavior and plus brain imaging) whether inhibition control abilities would be further deteriorated in the ADHD children due to the comorbidity of SLD.

Method

A total number of 90 children (aged 6-12 years) were recruited, including 30 ADHD, 30 ADHD+SLD (children with the comorbidity of ADHD and SLD), and 30 typically developing (TD) children. For each participant, a 44-channel functional near infrared spectroscopy (fNIRS) equipment was first adopted to capture behavioral and cortical hemodynamic responses during a two-choice Oddball task (a relatively new inhibition control paradigm). Then, 50 metrics were extracted, including 6 behavioral metrics (i.e., OddballACC, baselineACC, totalACC, OddballRT, baselineRT, and totalRT) and 44 beta values in 44 channels based on general linear model. Finally, differences in those 50 metrics among the TD, ADHD, and ADHD+SLD children were analyzed.

Results

Findings showed that: (1) OddballACC (i.e., the response accuracy in deviant stimuli) is the most sensitive metric in identifying the differences between the ADHD and ADHD+SLD children; and (2) The ADHD+SLD children exhibited decreased behavioral response accuracy and brain activation level in some channels (e.g., channel CH35) than both the ADHD and TD children.

Discussion

Findings seem to support that inhibition control abilities would be further decreased in the ADHD children due to the comorbidity of SLD.

Cortical activity in patients with high-functioning ischemic stroke during the Purdue Pegboard Test: insights into bimanual coordinated fine motor skills with functional near-infrared spectroscopy

After stroke, even high-functioning individuals may experience compromised bimanual coordination and fine motor dexterity, leading to reduced functional independence. Bilateral arm training has been proposed as a promising intervention to address these deficits. However, the neural basis of the impairment of functional fine motor skills and their relationship to bimanual coordination performance in stroke patients remains unclear, limiting the development of more targeted interventions. To address this gap, our study employed functional near-infrared spectroscopy to investigate cortical responses in patients after stroke as they perform functional tasks that engage fine motor control and coordination. Twenty-four high-functioning patients with ischemic stroke (7 women, 17 men; mean age 64.75 ± 10.84 years) participated in this cross-sectional observational study and completed four subtasks from the Purdue Pegboard Test, which measures unimanual and bimanual finger and hand dexterity. We found significant bilateral activation of the sensorimotor cortices during all Purdue Pegboard Test subtasks, with bimanual tasks inducing higher cortical activation than the assembly subtask. Importantly, patients with better bimanual coordination exhibited lower cortical activation during the other three Purdue Pegboard Test subtasks. Notably, the observed neural response patterns varied depending on the specific subtask. In the unaffected hand task, the differences were primarily observed in the ipsilesional hemisphere. In contrast, the bilateral sensorimotor cortices and the contralesional hemisphere played a more prominent role in the bimanual task and assembly task, respectively. While significant correlations were found between cortical activation and unimanual tasks, no significant correlations were observed with bimanual tasks. This study provides insights into the neural basis of bimanual coordination and fine motor skills in high-functioning patients after stroke, highlighting task-dependent neural responses. The findings also suggest that patients who exhibit better bimanual performance demonstrate more efficient cortical activation. Therefore, incorporating bilateral arm training in post-stroke rehabilitation is important for better outcomes. The combination of functional near-infrared spectroscopy with functional motor paradigms is valuable for assessing skills and developing targeted interventions in stroke rehabilitation.

ASD and ADHD: Divergent activating patterns of prefrontal cortex in executive function tasks?

The functional Near-infrared Spectroscopy (fNIRS) has been more and more widely used to measure the activation state of prefrontal cortex when performing function-related tasks among children with various developmental disorders. Children with autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) have shown obvious executive function defects. We aimed to summarize the studies with fNIRS, to summarize the activation patterns of prefrontal cortex (PFC) of participants with ASD or ADHD in performing functional tasks. We selected 630 articles according to PRISMA guidelines, and the eligibility criteria were: 6-16 years old individuals diagnosed with ASD or ADHD by DSM-4 or 5, using fNIRS, having executive function (EF) task, typical development (TD) control, and between-group comparison of PFC activation. Eleven studies were finally included in the quantitative analysis, and compared to TD, ASD and ADHD showed the opposite PFC activation patterns during n-back tasks. We discussed the task-specific PFC activation in young participants with ASD and ADHD, and provided some new ideas on that issue.

Abnormal prefrontal cortical activation during the GO/NOGO and verbal fluency tasks in adult patients with comorbid generalized anxiety disorder and attention-deficit/hyperactivity disorder: An fNIRS study

Generalized anxiety disorder (GAD) and adult attention-deficit/hyperactivity disorder (ADHD) are commonly reported comorbidities. Adult GAD patients with comorbid ADHD are often underdiagnosed and undertreated. To explore the clinical value of functional near-infrared spectroscopy (fNIRS) data for assisting in the accurate diagnosis of ADHD in individuals with GAD, haemoglobin (HbO) concentration changes in the prefrontal cortex (PFC) were detected via fNIRS in 49 patients with both GAD and ADHD, 46 patients with GAD, and 34 healthy controls (HCs) during a verbal fluency task (VFT) and a GO/NOGO task. The correlations between PFC fNIRS data and the severity of inattention and hyperactivity symptoms assessed using the adult ADHD Self-Report Scale (ASRS) were analyzed. Our results showed that, during the GO/NOGO task, channels in the left dorsolateral PFC (channels 28 and 29) were hyperactivated, while channels in the medial PFC (channels 36, 37, and 47) were hypoactivated in participants with ADHD and GAD compared with those with GAD alone. During the VFT, compared with the HC group, both the ADHD + GAD group and the GAD group exhibited significantly decreased HbO activation in the medial PFC (channels 37, 38, and 48) and in the left ventrolateral PFC (channel 39); moreover, no difference was found between the ADHD + GAD group and the GAD group. Activation in the left dorsolateral PFC (channels 28 and 29) during the GO/NOGO task showed a significant positive correlation with ASRS-inattention scores. Our results indicated that fNIRS data collected during the GO/NOGO task may help to distinguish patients with comorbid GAD and ADHD from those with GAD alone.

A scoping review of utilization of the verbal fluency task in Chinese and Japanese clinical settings with near-infrared spectroscopy

This review targets the application of the Verbal Fluency Task (VFT) in conjunction with functional near-infrared spectroscopy (fNIRS) for diagnosing psychiatric disorders, specifically in the contexts of China and Japan. These two countries are at the forefront of integrating fNIRS with VFT in clinical psychiatry, often employing this combination as a complementary tool alongside traditional psychiatric examinations. Our study aims to synthesize research findings on the hemodynamic responses elicited by VFT task in clinical settings of the two countries, analyzing variations in task design (phonological versus semantic), stimulus modality (auditory versus visual), and the impact of language typology. The focus on China and Japan is crucial, as it provides insights into the unique applications and adaptations of VFT in these linguistically and culturally distinct environments. By exploring these specific cases, our review underscores the importance of tailoring VFT to fit the linguistic and cultural context, thereby enhancing its validity and utility in cross-cultural psychiatric assessments.

The association of depressive sarcopenia and cognitive decline among the elderly: Evidence from the Survey of Health and Retirement in Europe

OBJECTIVES

The present study aimed to explore the relationship between baseline different sarcopenia statuses combined with different depression statuses and long-term cognitive functions.

METHODS

Finally, a total of 4289 individuals aged 50 years or older from wave 2 to wave 8 of the Survey of Health, Ageing and Retirement in Europe were included in this study. The generalized estimated equation model was used to explore the baseline effect of depression with sarcopenia on long-term cognitive function. Stratified Analyses according to gender, education, region, and family economic level were performed. Sensitivity analyses of wave 5 to wave 8 were conducted to ensure the robustness of the results.

RESULTS

Groups of depression with non-sarcopenia (β = -0.40, 95%CI: -0.59 ~ -0.20, P < 0.001), non-depression with sarcopenia (β = -1.11, 95%CI: -1.91 ~ -0.31, P = 0.007), and depression with sarcopenia (β = -1.19, 95%CI: -1.89 ~ -0.50, P = 0.001) were inversely associated with cognition scores compared with the group of non-depression with non-sarcopenia. Stratified Analysis displayed differences in negative association of depression status with sarcopenia status and cognition. Sensitivity analyses yielded similar results. Other than numeracy, depression with sarcopenia (β = -1.81, 95%CI: -2.45 ~ -1.18, P < 0.001; β = -10.68, 95%CI: -1.05 ~ -0.31, P < 0.001; β = -0.51, 95%CI: -0.65 ~ -0.37, P < 0.001; β = -0.41, 95%CI: -0.55 ~ -0.27, P < 0.001) were inversely associated with cognitive function, orientation, words list learning test and fluency.

CONCLUSIONS

Preliminary depressive sarcopenia appears to increase the risk of cognitive decline. There was a downward trend in total cognitive function. The effect of depression combined with sarcopenia on cognitive function may exist in differences in gender, education, region, and family economic level.

Gender differences in brain region activation during verbal fluency task as detected by fNIRS in patients with depression

BACKGROUND

Gender plays a role in the mechanisms of depression, but fewer studies have focused on gender differences in the abnormal activation of brain regions when patients perform specific cognitive tasks.

METHODS

A total of 110 major depressive disorder (MDD) patients and 106 healthy controls were recruited. The relative change in oxygen-haemoglobin (oxy-Hb) concentration during the verbal fluency task were measured by a 52-channel near-infra-red spectroscopy (NIRS) system. Differences in brain region activation between patients and healthy controls and between genders of depression patients were compared.

RESULTS

MDD patients demonstrated significantly decreased [oxy-Hb] changes in the right inferior frontal gyrus (p = 0.043) compared to healthy controls. A marked increase in leftward functional language lateralisation in the inferior frontal gyrus was observed in the MDD group in contrast to the HC group (p = 0.039). Furthermore, female patients in the MDD group exhibited significant reductions in [oxy-Hb] changes in the right frontal region (specifically, the superior and middle frontal gyrus; p = 0.037) compared with male patients.

CONCLUSIONS

Gender impacts depression-related brain activation during cognitive tasks, potentially influencing depression's pathogenesis.

Psychological characteristics and emotional difficulties underlying school refusal in adolescents using functional near-infrared spectroscopy

BACKGROUND

This study aims to explore the psychological characteristics, related emotional problems and potential NIR brain function mechanism of adolescents who refuse to attend school.

METHODS

The study included 38 adolescents (12-18 years old) who were not attending school and 35 healthy controls (12-18 years old) who are attending school regularly. Participants completed (1) general demographics, (2) Eysenck Personality Questionnaire (EPQ), (3) Zung Self-Rating Depression Scale (SDS), (4) Zung Self-Rating Anxiety Scale (SAS), and (5) Symptom Checklist-90 (SCL-90). In addition to the clinical tests, participants completed functional near-infrared spectroscopy (fNIRS). Mental health, personality, and emotional state were evaluated in both groups to explore the differences and to understand the underlying mechanisms of school refusal during adolescence.

RESULTS

Adolescents who did not attend school had higher neuroticism scores on the Eysenck Personality Questionnaire than healthy controls (p(FDR) < 0.001), introversion and concealment scores were lower than those of healthy controls (p(FDR) < 0.001), there was no significant difference in psychoticism scores between groups. SDS, SAS, SCL-90 scores and factor scores were higher than those of healthy control group (p(FDR) < 0.001), NIR functional brain imaging was different from healthy control group in the 12 and 27 channels (p(FDR) = 0.030, p(FDR) = 0.018), and no difference was found in the remaining channels (p(FDR) > 0.05). There were statistically significant differences in age and gender between the adolescents who refused school and the control group (p(FDR) < 0.001).

CONCLUSION

School refusal adolescents are relatively introverted and sensitive and need more attention in daily life. Although the adolescents' emotional problems did not reach the diagnostic criteria of depressive disorder and anxiety disorder, their scores were still higher than those of the control group, suggesting that we should pay more attention to their emotional problems in order to better help them return to school. Using fNIRS, it was found that abnormalities in frontal lobe regions in adolescents with school refusal behaviors, which would contribute to early diagnosis and timely intervention of school refusal behaviors.

Effects of age, gender, and education on task performance and prefrontal cortex processing during emotional and non-emotional verbal fluency tests

The emotional semantic fluency test (SFT) is an emerging verbal fluency test that requires controlled access to emotional lexical information. Currently, how demographic variables influence neurocognitive processing during this test remains elusive. The present study compared the effects of age, gender, and education on task performance and prefrontal cortex (PFC) processing during the non-emotional and emotional SFTs. One-hundred and thirty-three Cantonese-speaking adults aged 18-79 performed the non-emotional and emotional SFTs while their PFC activation was measured using functional near-infrared spectroscopy. Results showed that more education predicted better non-emotional SFT performance, whereas younger age, being female, and more education predicted better emotional SFT performance. Only age significantly affected PFC activation during the SFTs, and the effect was comparable between the two SFTs. Thus, compared with its non-emotional analog, the emotional SFT is influenced by overlapping yet distinct demographic variables. There is a similar age-related reorganization of PFC function across SFT performances.

The changes of neuroactivity of Tui Na (Chinese massage) at Hegu acupoint on sensorimotor cortex in stroke patients with upper limb motor dysfunction: a fNIRS study

BACKGROUND

Tui Na (Chinese massage) is a relatively simple, inexpensive, and non-invasive intervention, and has been used to treat stroke patients for many years in China. Tui Na acts on specific parts of the body which are called meridians and acupoints to achieve the role of treating diseases. Yet the underlying neural mechanism associated with Tui Na is not clear due to the lack of detection methods.

OBJECTIVE

Functional near-infrared spectroscopy (fNIRS) was used to explore the changes of sensorimotor cortical neural activity in patients with upper limb motor dysfunction of stroke and healthy control groups during Tui Na Hegu Point.

METHODS

Ten patients with unilateral upper limb motor dysfunction after stroke and eight healthy subjects received Tui Na. fNIRS was used to record the hemodynamic data in the sensorimotor cortex and the changes in blood flow were calculated based on oxygenated hemoglobin (Oxy-Hb), the task session involved repetitive Tui Na on Hegu acupoint, using a block design [six cycles: rest (20 seconds); Tui Na (20 seconds); rest (30 seconds)]. The changes in neural activity in sensorimotor cortex could be inferred according to the principle of neurovascular coupling, and the number of activated channels in the bilateral hemisphere was used to calculate the lateralization index.

RESULT

1. For hemodynamic response induced by Hegu acupoint Tui Na, a dominant increase in the contralesional primary sensorimotor cortex during Hegu point Tui Na of the less affected arm in stroke patients was observed, as well as that in healthy controls, while this contralateral pattern was absent during Hegu point Tui Na of the affected arm in stroke patients. 2. Concerning the lateralization index in stroke patients, a significant difference was observed between lateralization index values for the affected arm and the less affected arm (P < 0.05). Wilcoxon tests showed a significant difference between lateralization index values for the affected arm in stroke patients and lateralization index values for the dominant upper limb in healthy controls (P < 0.05), and no significant difference between lateralization index values for the less affected arm in stroke patients and that in healthy controls (P = 0.36).

CONCLUSION

The combination of Tui Na and fNIRS has the potential to reflect the functional status of sensorimotor neural circuits. The changes of neuroactivity in the sensorimotor cortex when Tui Na Hegu acupoint indicate that there is a certain correlation between acupoints in traditional Chinese medicine and neural circuits.

Improving Accuracy of ADHD Diagnosis with the Combination of Brain Imaging and Behavioral Measures

Neuropsychological measures may improve Attention-deficit/hyperactivity disorder (ADHD) diagnostic accuracy and enhance treatment response detection. Highquality evaluation indicators are necessary for accurate diagnosis of ADHD. Due to the high complexity of the pathogenesis of ADHD, it may not be possible to accurately diagnose ADHD only by relying on behavioral assessment or brain imaging examination. Therefore, the authors propose a comprehensive index that combines brain imaging behavioral and measures. The results showed that the classification performance of the composite index was better than that of the single behavior or brain image index.Clinical Relevance- The results of this study help to remind practicing clinicians to consider the results of multiple clinical examinations when clinically diagnosing ADHD patients.

Regulating effect of virtual reality restorative environment on prefrontal cortex dysfunction after night shifts in medical staff: an fNIRS study protocol for a randomized controlled trial in Dalian, China

BACKGROUND

Night shift work-related disturbed biological rhythm and insufficient sleep affect the functioning of brain activity and thus impair cognitive performance and mood state, which potentially leads to negative and even devastating results for both individuals and patients. A virtual reality (VR)-based restorative environment has shown to be an effective new technique to reduce stress and improve cognitive performance, but little is known about its mechanism of improving neuronal activity and connectivity.

METHODS

This is a randomized, controlled, single-center clinical trial. A total of 140 medical staff will be enrolled and randomized in a 1:1 allocation to either the VR immersion group (intervention group) or the control group. In the morning after the night shift, the participants in the intervention group will watch 360° panoramic videos of immersive VR natural restorative environments for 10 min, while the participants in the control group will just rest for 10 min. Assessments of abbreviated Profile of Mood States Questionnaire (POMS) and verbal fluency task (VFT) performances, as well as oxygenated hemoglobin (oxy-Hb) and deoxygenated hemoglobin (deoxy-Hb) and total hemoglobin concentration acquired by functional near-infrared spectroscopy (fNIRS) will be performed at baseline (day work), the morning after night shift but before the intervention (previous) and after intervention (post). Data collected after a night shift will be compared to baseline performance as well as between the two groups.

DISCUSSION

This trial will investigate the effects of the night shift and VR-based restorative environment intervention on mood, cognitive performance, and neuronal activity and connectivity. A positive result in this trial could encourage hospitals to apply VR technology to reduce physical and mental dysfunction during of night shifts among medical staff in every department. Furthermore, the findings from this study will contribute to understanding the underlying neuromodulation mechanisms of how restorative environments influence mood and cognition.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2200064769 . Registered on 17 October 2022.

Functional near-infrared spectroscopy in elderly patients with four types of dementia

BACKGROUND

Functional near-infrared spectroscopy (fNIRS) is commonly used to study human brain function by measuring the hemodynamic signals originating from cortical activation and provides a new noninvasive detection method for identifying dementia.

AIM

To investigate the fNIRS imaging technique and its clinical application in differential diagnosis of subtype dementias including frontotemporal lobe dementia, Lewy body dementia, Parkinson’s disease dementia (PDD) and Alzheimer’s disease (AD).

METHODS

Four patients with different types of dementia were examined with fNIRS during two tasks and a resting state. We adopted the verbal fluency task, working memory task and resting state task. Each patient was compared on the same task. We conducted and analyzed the fNIRS data using a general linear model and Pearson’s correlation analysis.

RESULTS

Compared with other types of dementias, fNIRS showed the left frontotemporal and prefrontal lobes to be poorly activated during the verbal fluency task in frontotemporal dementia. In Lewy body dementia, severe asymmetry of prefrontal lobes appeared during both verbal fluency and working memory tasks, and the patient had low functional connectivity during a resting state. In PDD, the patient’s prefrontal cortex showed lower excitability than the temporal lobe during the verbal fluency task, while the prefrontal cortex showed higher excitability during the working memory task. The patient with AD showed poor prefrontal and temporal activation during the working memory task, and more activation of frontopolar instead of the dorsolateral prefrontal cortex.

CONCLUSION

Different hemodynamic characteristics of four types of dementia (as seen by fNIRS imaging) provides evidence that fNIRS can serve as a potential tool for the diagnosis between dementia subtypes.

Neuropsychological assessment of Romanian burning mouth syndrome patients: stress, depression, sleep disturbance, and verbal fluency impairments

Burning Mouth Syndrome (BMS) is a chronic condition characterized by a burning sensation in the oral mucosa, lasting more than 2 hours daily for more than 3 months, without clinical and/or laboratory evidence. BMS is often comorbid with mood, and psychiatric disorders, and a complex pathophysiology and interaction between impairments in nociceptive processing and psychologic function is occurring. In this work, we aimed to define the neuropsychological profile specific for BMS patients for a better management of this complex disease. We conducted a case-control study comparing 120 BMS patients and 110 non-BMS individuals (CTRL). Sociodemographic data and lifestyle habits, were collected, along with data regarding quality of life (SF-36 scale), stress (PSS), depression and anxiety (MADRS and HADS scales), sleep quality (PSQI scale), and cognitive functions (MoCA, SVF and PVF tests). The statistical analysis revealed a lower general quality of life (p < 0.001), worse sleep quality (p < 0.001) in BMS patients than CTRL. The BMS patients also displayed a higher prevalence of mild depressive symptoms than CTRL applying the MADRS (p < 0.001) and HADS-Depression scales (p = 0.001), whereas no differences in anxiety symptoms were found between the two groups (p = 0.174). Moreover, reduced scores semantic and phonemic verbal fluency tests (p < 0.05) were found, but no change in cognition was observed through MoCA (p = 0.551). Our results highlight that synergy between dentistry and neuropsychiatric assessment is essential for a successful management of BMS.

Insomniacs show greater prefrontal activation during verbal fluency task compared to non-insomniacs: a functional near-infrared spectroscopy investigation of depression in patients

BACKGROUND

Previous studies have shown that insomnia affects human prefrontal function and that there are specific patterns of brain activation to counteract sleep and improve cognition. However, the effects of insomnia on the prefrontal cortex of MDD (major depressive disorder) patients and the patterns of activation to counteract sleep in MDD patients remain unclear. The aim of this study is to examine this using fNIRS (functional near-infrared spectroscopy).

METHODS

Eighty depressed patients and 44 healthy controls were recruited for this study. fNIRS was used to assess changes in the concentration of oxygenated hemoglobin ([oxy-Hb]) in the prefrontal cortex of all participants during the VFT (verbal fluency test) and to record the number of words created to assess cognitive ability. The Pittsburgh Sleep Quality Index was used to assess sleep quality, and the Hamilton Rating Scale for Depression (24-item) and Hamilton Rating Scale for Anxiety (14-item) were used to assess the severity of depression and anxiety.

RESULTS

When comparing patients, the healthy control group had significantly higher [oxy-Hb] values in the bilateral prefrontal cortex during VFT than the MDD group. In the MDD group, the [oxy-Hb] values in all brain regions except the right DLPFC were significantly higher in the group with insomnia than in the group without insomnia, but their VFT performance was significantly lower than in the group without insomnia and the healthy group. PSQI scores were positively correlated with [oxy-Hb] values in some left-brain regions, whereas HAMD and HAMA scores were not correlated with [oxy-Hb] values.

CONCLUSION

The PFC was significantly less active during VFT in those with MDD than in healthy controls. All brain regions, except the right DLPFC, were significantly more active in MDD patients with insomnia than in those without insomnia, suggesting that sleep quality needs to be an important indicator in fNIRS screening. In addition, there was a positive correlation between the severity of insomnia in the left VLPFC and the level of activation, suggesting a role for the left brain region in the neurophysiology of overcoming sleepiness in MDD patients. these findings may provide new ideas for the treatment of MDD patients in the future.

TRIAL REGISTRATION

Our experiment was registered in the China Clinical Trial Registry (registration number ChiCTR2200065622) on November 10.( The first patient was recruited in 10/11/2022.).

Differentiating people with schizophrenia from healthy controls in a developing Country: An evaluation of portable functional near infrared spectroscopy (fNIRS) as an adjunct diagnostic tool

INTRODUCTION

This study aimed to evaluate portable functional near-infrared spectroscopy (fNIRS) device as an adjunct diagnostic tool in Vietnam to assess hemodynamics when people with schizophrenia and healthy controls performed cognitive tasks.

METHODS

One hundred fifty-seven participants were divided into schizophrenia (n = 110) and healthy controls group (n = 47), which were recruited by match of age, and gender. Hemodynamic responses in the frontal cortex were monitored with a 48-channel portable device during the Stroop Color-Word Test (SCWT) and Verbal Fluency Test (VFT). General linear model compared the differences in oxyhemoglobin (HbO₂) levels between the two groups. The Receiver Operating Characteristic (ROC) graph was generated for each neuroanatomical area.

RESULTS

People with schizophrenia did not show significant activation in the frontal lobe during the SCWT and VFT as compared to pre-task. During the VFT, the area under the ROC curve of the bilateral dorsolateral prefrontal cortex, bilateral orbitofrontal cortex, bilateral frontopolar prefrontal cortex, and bilateral ventrolateral prefrontal cortex were greater than 0.7 (p < 0.001). The area under the ROC curve (AUC) for the right orbitofrontal cortex was maximal during the VFT (AUC = 0.802, 95%CI = 0.731-0.872). The Youden's index reached a peak (0.57) at the optimal cut-point value (HbO₂ cutoff <0.209 μmol/ml for schizophrenia) in which the sensitivity was 85%; specificity was 72%; positive predictive value (PPV) was 0.88; negative predictive value (NPV) was 0.68 and correct classification rate was 76%.

DISCUSSION

Assessing hemodynamics during VFT by portable fNIRS offers the potential as an adjunct diagnostic tool for schizophrenia in developing countries.

Atypical frontotemporal cortical activity in first-episode adolescent-onset schizophrenia during verbal fluency task: A functional near-infrared spectroscopy study

Background

Frontotemporal cortex dysfunction has been found to be associated with cognitive impairment in patients with schizophrenia (SCZ). In patients with adolescent-onset SCZ, a more serious type of SCZ with poorer functional outcome, cognitive impairment appeared to occur at an early stage of the disease. However, the characteristics of frontotemporal cortex involvement in adolescent patients with cognitive impairment are still unclear. In the present study, we aimed to illustrate the frontotemporal hemodynamic response during a cognitive task in adolescents with first-episode SCZ.

Methods

Adolescents with first-episode SCZ who were aged 12-17 and demographically matched healthy controls (HCs) were recruited. We used a 48-channel functional near-infrared spectroscopy (fNIRS) system to record the concentration of oxygenated hemoglobin (oxy-Hb) in the participants' frontotemporal area during a verbal fluency task (VFT) and analyzed its correlation with clinical characteristics.

Results

Data from 36 adolescents with SCZ and 38 HCs were included in the analyses. Significant differences were found between patients with SCZ and HCs in 24 channels, mainly covering the dorsolateral prefrontal cortex, superior and middle temporal gyrus and frontopolar area. Adolescents with SCZ showed no increase of oxy-Hb concentration in most channels, while the VFT performance was comparable between the two groups. In SCZ, the intensity of activation was not associated with the severity of symptoms. Finally, receiver operating characteristic analysis indicated that the changes in oxy-Hb concentration could help distinguish the two groups.

Conclusion

Adolescents with first-episode SCZ showed atypical cortical activity in the frontotemporal area during the VFT, and fNIRS features might be more sensitive indicators in cognitive assessment, indicating that the characteristic hemodynamic response pattern might be potential imaging biomarkers for this population.

Current opinions on the present and future use of functional near-infrared spectroscopy in psychiatry

Functional near-infrared spectroscopy (fNIRS) is an optical imaging technique for assessing human brain activity by noninvasively measuring the fluctuation of cerebral oxygenated- and deoxygenated-hemoglobin concentrations associated with neuronal activity. Owing to its superior mobility, low cost, and good tolerance for motion, the past few decades have witnessed a rapid increase in the research and clinical use of fNIRS in a variety of psychiatric disorders. In this perspective article, we first briefly summarize the state-of-the-art concerning fNIRS research in psychiatry. In particular, we highlight the diverse applications of fNIRS in psychiatric research, the advanced development of fNIRS instruments, and novel fNIRS study designs for exploring brain activity associated with psychiatric disorders. We then discuss some of the open challenges and share our perspectives on the future of fNIRS in psychiatric research and clinical practice. We conclude that fNIRS holds promise for becoming a useful tool in clinical psychiatric settings with respect to developing closed-loop systems and improving individualized treatments and diagnostics.

Study protocol of a randomized controlled trial for the synergizing effects of rTMS and Tui Na on upper limb motor function and cortical activity in ischemic stroke

Upper limb motor dysfunction after stroke is a serious threat to the living quality of patients and their families. Recovery of upper limb motor function after stroke largely relies on the activation and remodeling of neural circuits. rTMS (repetitive transcranial magnetic stimulation) has been proved to promote the reconstruction of neural synapses and neural circuits. However, there are still a large number of patients who cannot fully recover and leave behind varying degrees of dysfunction. Considering the systemic pathology after stroke, in addition to focal brain injury, stroke can also cause extensive dysfunction of peripheral organs. The rehabilitation strategy for stroke should combine the treatment of primary brain lesions with the intervention of secondary systemic damage. The aim of this trial is to verify the efficacy of rTMS synergize with Tui Na (Chinese Massage) on upper limb motor function after ischemic stroke, and to explore the mechanism of activation and remodeling of sensorimotor neural circuits with functional near-infrared spectroscopy. Ninety patients will be randomly assigned to either rTMS + Tui Na + conventional rehabilitation group (the experimental group) or rTMS + conventional rehabilitation group (the control group) in 1:1 ratio. Intervention is conducted five sessions a week, with a total of twenty sessions. The primary outcome is Fugl-Meyer Assessment, and the secondary outcomes include Muscle Strength, Modified Ashworth Assessment, Modified Barthel Index Assessment, motor evoked potentials and functional near-infrared spectroscopy. There are four time points for the evaluation, including baseline, 2 weeks and 4 weeks after the start of treatment, and 4 weeks after the end of treatment. This study is a randomized controlled trial. This study was approved by Institutional Ethics Committee of Shanghai Third Rehabilitation Hospital Affiliated to Shanghai University of Traditional Chinese Medicine (approval No. SH3RH-2021-EC-012) on December, 16th, 2021. The protocol was registered with Chinese Clinical Trial Registry (ChiCTR2200056266), on February 3th, 2022. Patient recruitment was initiated on February 10th, 2022, and the study will be continued until December 2023.

Hemodynamic analysis of the frontal cortex using multi-task fNIRS in major depressive disorder

BACKGROUND

Appropriate task selection is the key to fNIRS-based major depressive disorder (MDD) diagnosis and treatment; however, there exists no unified rule for task selection, which limits its clinical application.

METHODS

Four tasks were employed to investigate the hemodynamic characteristics of MDD during motor, emotional, cognitive, and combinational tasks. A total of 69 subjects were studied: 50 with MDD and 19 healthy controls. The integral value of oxy-hemoglobin and the asymmetric characteristics of the bilateral frontal lobe were used to demonstrate the hemodynamic changes in MDD during different tasks. A detailed analysis and comparison among different tasks were conducted.

RESULTS

Compared with deoxy-hemoglobin (deoxy-Hb), oxy-Hb was more significant to differentiate between MDD subjects and healthy controls. In subjects with MDD, lower activation of the frontal lobe and smaller integral values of oxy-Hb were observed. In most task paradigms, MDD subjects and healthy controls exhibited diametrically opposite left-right frontal asymmetry. For the integral value of oxy-Hb and the asymmetric characteristics of the bilateral frontal lobe, the differences between MDD subjects and healthy controls under the combinational task were more significant than that under the single tasks.

LIMITATIONS

Brain fatigue patterns over time and their effect on the hemodynamic analysis of MDD should be studied further.

CONCLUSIONS

The difference in hemodynamic characteristics between MDD subjects and healthy controls is closely related to the choice of task, and the combinational task showed better discrimination than the single tasks. It provides guidance for the appropriate task design for MDD in clinics.

Aberrant prefrontal functional connectivity during verbal fluency test is associated with reading comprehension deficits in autism spectrum disorder: An fNIRS study

Children with autism spectrum disorder (ASD) show marked difficulties in reading comprehension, a complex cognitive skill fundamental to successful daily functioning that is associated with core executive functions. However, the neurophysiological mechanisms underlying reading comprehension deficits in these children remain elusive. Twenty-one right-handed males with high-functioning ASD (mean age = 10.24 years) and 23 age-, IQ-, educational level-, sex- and handedness-matched typically developing (TD; mean age = 10.14 years) individuals underwent a reading comprehension test and the semantic verbal fluency test that tapped core executive functions underlying reading comprehension during concurrent prefrontal functional near-infrared spectroscopy (fNIRS) measurement. Participants’ information processing efficiency was also assessed. High-functioning ASD children exhibited general reading comprehension [main effect of group: F(1,40) = 7.58, p = 0.009], selective verbal fluency deficits [Group × category interaction: F(1,42) = 4.90, p = 0.032] and slower processing speed (t42 = 2.36, p = 0.023). Regarding the hemodynamics of the prefrontal cortex (PFC), although ASD individuals showed comparable patterns of PFC brain activation to their healthy counterparts, lower PFC intrahemispheric [main effect of group: F(1,42) = 11.36, p = 0.002] and interhemispheric [main effect of group: F(1,42) = 7.79, p = 0.008] functional connectivity were evident during the semantic verbal fluency test. At the whole-group level, poorer reading comprehension performance was associated with poorer performance in the semantic verbal fluency test (r42 = 0.508, p &lt; 0.001). Moreover, poorer semantic verbal fluency test performance was associated with slower information processing speed (r42 = –0.312, p = 0.044), which is associated with reduced left medial PFC functional connectivity (r42 = –0.319, p = 0.040). Abnormal intrahemispheric and interhemispheric prefrontal hypoconnectivity is associated with deficits in executive processes essential for reading comprehension in ASD. Our study has provided important implications for the neuropsychological and neurophysiological mechanisms underlying reading comprehension deficits in ASD.

Characteristics of prefrontal activity during emotional and cognitive processing in patients with bipolar disorder: A multi-channel functional near-infrared spectroscopy study

Bipolar disorder (BD) is a recurrent chronic mental disorder with a broad profile of functional deficits including disturbed emotional processing and cognitive impairments. The goal of the current study was to further explore the underlying neural mechanism of dysfunction in patients with BD from a comprehensive perspective of both cognition and emotion. Forty-six clinical patients with BD and forty-five healthy controls performed emotion induction task and verbal fluency task (VFT), with frontal activity measured by functional near-infrared spectroscopy (fNIRS). Our results show distinct hemodynamic activity in the prefrontal region during emotional and cognitive processing between patients with BD and healthy controls. Patients with BD exhibit valence-dependent prefrontal cortex (PFC) hemodynamic response to emotional stimuli, with bilateral frontal hypoactivity indicating decreased positive reactivity and left frontal hyperactivity indicating increased negative reactivity. On the other hand, patients with BD showed impaired performance with bilateral frontal hypoactivity during VFT. Taken together, frontal dysfunction of cognition and emotionality in patients with BD probed by fNIRS would be a potential biomarker in clinical assessment.

Four-Class Classification of Neuropsychiatric Disorders by Use of Functional Near-Infrared Spectroscopy Derived Biomarkers

Diagnosis of most neuropsychiatric disorders relies on subjective measures, which makes the reliability of final clinical decisions questionable. The aim of this study was to propose a machine learning-based classification approach for objective diagnosis of three disorders of neuropsychiatric or neurological origin with functional near-infrared spectroscopy (fNIRS) derived biomarkers. Thirteen healthy adolescents and sixty-seven patients who were clinically diagnosed with migraine, obsessive compulsive disorder, or schizophrenia performed a Stroop task, while prefrontal cortex hemodynamics were monitored with fNIRS. Hemodynamic and cognitive features were extracted for training three supervised learning algorithms (naïve bayes (NB), linear discriminant analysis (LDA), and support vector machines (SVM)). The performance of each algorithm in correctly predicting the class of each participant across the four classes was tested with ten runs of a ten-fold cross-validation procedure. All algorithms achieved four-class classification performances with accuracies above 81% and specificities above 94%. SVM had the highest performance in terms of accuracy (85.1 ± 1.77%), sensitivity (84 ± 1.7%), specificity (95 ± 0.5%), precision (86 ± 1.6%), and F1-score (85 ± 1.7%). fNIRS-derived features have no subjective report bias when used for automated classification purposes. The presented methodology might have significant potential for assisting in the objective diagnosis of neuropsychiatric disorders associated with frontal lobe dysfunction.

Differential and subtype-specific neuroimaging abnormalities in amnestic and nonamnestic mild cognitive impairment: A systematic review and meta-analysis

While mild cognitive impairment (MCI) has been classified into amnestic MCI (aMCI) and nonamnestic MCI (naMCI), the neuropathological bases of these two subtypes remain elusive. Here, we performed a systematic review and meta-analysis to determine the subtype specificity of neuroimaging abnormalities in MCI and to identify neural features that may differ between aMCI and naMCI. We synthesized 50 studies that used common neuroimaging modalities, including magnetic resonance imaging and positron emission tomography, to compare brain atrophy, white matter abnormalities, cortical thinning, cerebral hypometabolism, amyloid/tau deposition, or other features among aMCI, naMCI, and normal cognition. Compared with normal cognition, aMCI shows diverse neuroimaging abnormalities of large effect sizes. In contrast, naMCI exhibits restricted abnormalities of small effect sizes. Some features, including medial temporal lobe atrophy and white matter abnormalities, are shared by the two MCI subtypes. Overall, brain abnormalities are worse, if not similar, in aMCI than in naMCI. The only neuroimaging abnormality specific to aMCI is increased amyloid burden; no feature specific to naMCI was found. Taken together, our findings have elucidated the neuropathological changes that occur in aMCI and naMCI. Clarifying the neuroimaging profiles of aMCI and naMCI can improve the early identification, differentiation, and intervention of prodromal dementia.

Frontal cortical activation during emotional and non-emotional verbal fluency tests

There has been growing recognition of the utility of combining the verbal fluency test and functional near-infrared spectroscopy (fNIRS) to assess brain functioning and to screen for psychiatric disorders. Recently, an emotional analogue of the semantic fluency test (SFT) has been developed that taps partly different processes from conventional verbal fluency tests. Nevertheless, neural processing during the emotional SFT remains elusive. Here, fNIRS was used to compare frontal cortical activation during emotional and non-emotional SFTs. The goal was to determine whether the emotional SFT activated overlapping yet distinct frontal cortical regions compared with the conventional, non-emotional SFT. Forty-three healthy young adults performed the emotional and non-emotional SFTs while hemodynamic changes in the bilateral frontopolar, dorsomedial, dorsolateral, ventrolateral, and posterolateral frontal cortices were measured by fNIRS. There were significant increases in oxyhemoglobin concentration and significant decreases in deoxyhemoglobin concentration (i.e., activation) in frontopolar, dorsolateral, and ventrolateral frontal regions during both the non-emotional and emotional SFTs. Also, complementary analyses conducted on changes in the two chromophores using classical and Bayesian hypothesis testing suggested that comparable frontal cortical regions were activated while performing the two tests. This similarity in activation occurred in a context where non-emotional and emotional SFT performances exhibited differential relationships with the overall level of negative mood symptoms. In conclusion, frontal cortical activation during the emotional SFT is similar to that during the conventional, non-emotional SFT. Given that there is evidence for discriminant validity for the emotional SFT, the neural mechanisms underlying the uniqueness of this test warrant further investigation.

Abnormal Prefrontal Functional Connectivity Is Associated with Inflexible Information Processing in Patients with Autism Spectrum Disorder (ASD): An fNIRS Study

Individuals with autism spectrum disorder (ASD) are characterized by impairments in flexibly acquiring and maintaining new information, as well as in applying learned information for problem solving. However, the neural mechanism underpinning such impairments remains unclear. This study investigated the flexibility in the acquisition and application of visual information in ASD (aged 14−21) when they performed the Wisconsin Card Sorting Test (WCST). Behavioral data including response accuracy and latency, and prefrontal hemodynamic data measured by functional near-infrared spectroscopy (fNIRS), were collected when individuals performed WCST. Canonical general linear model and functional connectivity analyses were performed to examine the prefrontal activation and synchronization patterns, respectively. Results showed that although ASD individuals (n = 29) achieved comparable accuracy rates when compared with age- and intelligence quotient (IQ)-matched typically developing (TD; n = 26) individuals (F1,53 = 3.15, p = 0.082), ASD individuals needed significantly more time to acquire and apply WCST card sorting rules (F1,53 = 17.92, p < 0.001). Moreover, ASD individuals showed significantly lower prefrontal functional connectivity than TD individuals during WCST (F1,42 = 9.99, p = 0.003). The hypoconnectivity in ASD individuals was highly significant in the right lateral PFC in the acquisition condition (p = 0.005) and in the bilateral lateral PFC in the application condition (ps = 0.006). Furthermore, slower WCST reaction time was correlated with lower bilateral lateral PFC functional connectivity only in the application condition (ps = 0.003) but not the acquisition condition. Impairment in information acquisition and application is evident in ASD individuals and is mediated by processing speed, which is associated with lower functional connectivity in the bilateral lateral PFC when these individuals apply learned rules to solve novel problems.

Cortical activation and functional connectivity during the verbal fluency task for adolescent-onset depression: A multi-channel NIRS study

OBJECTIVE

Depression disorder is accompanied by cognitive impairments. However, there is limited research focused on cognitive impairments and their neurological mechanism in adolescents with depression. The purpose of the current study is to illustrate the differences in brain activity patterns between depressed adolescents and healthy controls (HCs).

METHOD

A total of 72 adolescents with depression, as well as 74 HCs, were recruited. We utilized functional near-infrared spectroscopy (fNIRS) to monitor the concentrations of oxyhemoglobin (Oxy-Hb) in the brains of participants while they performed the verbal fluency task (VFT) to examine cognitive impairment in adolescents with depression.

RESULTS

Our study demonstrated that adolescents with depression had significantly less cortical activation in the hemodynamic responses of Oxy-Hb at channels mainly located in the prefrontal cortex (PFC) than HCs during the 60-s task period (false discovery rate (FDR)-corrected p < 0.05). The mean channel-to-channel connectivity was 0.400 for HCs (SD = 0.149) and 0.303 (SD = 0.138) for adolescents with depression, and the HC group had a higher mean channel-to-channel connectivity strength than the depression group (t = -15.586, p < 0.001). For the patient group, we found significant negative correlations between HAMD scores and mean Oxy-Hb changes in Channel 38 (r = -0.33, p < 0.01), Channel 39 (r = -0.34, p < 0.01), Channel 41 (r = -0.25, p < 0.05), Channel 42 (r = -0.28, p < 0.05), and Channel 44 (r = -0.27, p < 0.05), and these channels were mainly located in areas with little difference between groups.

CONCLUSIONS

Our study provides neurological evidence about the executive function (EF) in depressed adolescents. Adolescents with depression exhibited an abnormal activation pattern and decreased task-related functional connectivity compared to HCs. The changed Oxy-Hb concentration of PFC during VFT was not sensitive to depression symptoms.

Increased Prefrontal Activation During Verbal Fluency Task After Repetitive Transcranial Magnetic Stimulation Treatment in Depression: A Functional Near-Infrared Spectroscopy Study

BACKGROUND

Previous studies have shown the clinical effect of 2 Hz repetitive transcranial magnetic stimulation (rTMS) for depression; however, its underlying neural mechanisms are poorly understood. The aim of this study was to examine the effects of rTMS on the activity of the prefrontal cortex in patients with depression, using functional near-infrared spectroscopy (fNIRS).

METHODS

Forty patients with major depressive disorder (MDD) and 40 healthy controls were enrolled in this study. Patients underwent 4 weeks of 2 Hz TMS delivered to the right dorsolateral prefrontal cortex (DLPFC). fNIRS was used to measure the changes in the concentration of oxygenated hemoglobin ([oxy-Hb]) in the prefrontal cortex during a verbal fluency task (VFT) in depressed patients before and after rTMS treatment. The severity of depression was assessed using the Hamilton Rating Scale for Depression-24 item (HAMD-24).

RESULTS

Prior to rTMS, depressed patients exhibited significantly smaller [oxy-Hb] values in the bilateral prefrontal cortex during the VFT compared with the healthy controls. After 4 weeks of 2 Hz right DLPFC rTMS treatment, increased [oxy-Hb] values in the bilateral frontopolar prefrontal cortex (FPPFC), ventrolateral prefrontal cortex (VLPFC) and left DLPFC during the VFT were observed in depressed patients. The increased [oxy-Hb] values from baseline to post-treatment in the right VLPFC in depressed patients were positively related to the reduction of HAMD score following rTMS.

CONCLUSION

These findings suggest that the function of the prefrontal cortex in depressed patients was impaired and could be recovered by 2 Hz rTMS. The fNIRS-measured prefrontal activation during a cognitive task is a potential biomarker for monitoring depressed patients' treatment response to rTMS.

The promising fNIRS: Uncovering the function of prefrontal working memory networks based on multi-cognitive tasks

The diversity of cognitive task paradigms using functional near-infrared spectroscopy (fNIRS) and the lack of theoretical explanations for these functional imaging atlases have greatly hindered the application of fNIRS in psychiatry. The fNIRS brain imaging based on multiple cognitive tasks could generally reflect the working patterns and neurovascular coupling changes in the prefrontal working memory network. By alternating the stimulation patterns of resting and task states, six typical symptom-related functional brain imaging waveforms related to psychiatric disorders are identified and three joint networks of the prefrontal working memory, namely, the attentional working memory primary coordination network, the perceptual content working memory secondary network, and the emotional-behavioral working memory executive network, are initially represented. This is the first attempt to characterize the cognitive, emotional, and behavioral regulation of the prefrontal working memory network using fNIRS, which may promote the application of fNIRS in clinical settings.

Impaired Oxygenation of the Prefrontal Cortex During Verbal Fluency Task in Young Adults With Major Depressive Disorder and Suicidality: A Functional Near-Infrared Spectroscopy Study

BACKGROUND

Few previous studies have focused on prefrontal activation in young adults diagnosed with major depressive disorder (MDD) and suicidality via functional near-infrared spectroscopy (fNIRS).

MATERIALS AND METHODS

A total of 59 healthy controls (HCs), 35 patients with MDD but without suicidality, and 25 patients with MDD and suicidality, between the ages of 18-34 years, were enrolled. Changes in oxygenated hemoglobin (oxy-Hb) levels of the prefrontal cortex at baseline, 4 weeks, and 8 weeks, were evaluated using a protocol consisting of three consecutively repeated trials of rest, speech, and verbal fluency test (VFT) via fNIRS. MDD was diagnosed and suicidality was evaluated based on Mini International Neuropsychiatric Interview (MINI).

RESULTS

Oxy-Hb levels were impaired in patients with MDD compared with HCs (p = 0.018 for left prefrontal cortex; p = 0.021 for right ventromedial prefrontal cortex; p = 0.002 for left frontopolar cortex). Among the three groups including HCs, MDD without suicidality, and MDD with suicidality, prefrontal oxygenation was most decreased in MDD patients with suicidality. A significantly impaired prefrontal oxygenation in the right ventrolateral prefrontal cortex (VLPFC) was detected after adjusting for covariates in MDD patients with suicidality, compared to those without suicidality.

CONCLUSION

Impaired prefrontal oxygenation during cognitive execution may serve as a diagnostic biomarker for suicidality in young adult patients with MDD.

Dose-response relationship between iTBS and prefrontal activation during executive functioning: A fNIRS study

INTRODUCTION

Intermittent theta-burst stimulation (iTBS) is a non-invasive brain stimulation paradigm that has demonstrated promising therapeutic benefits for a variety of neuropsychiatric disorders. It has recently garnered widespread favor among researchers and clinicians, owing to its comparable potentiation effects as conventional high-frequency repetitive transcranial magnetic stimulation (rTMS), but administered in a much shorter time frame. However, there is still a lack of agreement over the optimal stimulation intensity, particularly when targeting the prefrontal regions. The objective of this study was to systematically investigate the influence of different stimulation intensities of iTBS, applied over the left dorsolateral prefrontal cortex (DLPFC), on brain activity and executive function in healthy adults.

METHODS

Twenty young healthy adults were enrolled in this randomized cross-over experiment. All participants received a single session iTBS over the left DLPFC at intensities of 50, 70, or 100% of their individual resting motor threshold (RMT), each on separate visits. Functional near-infrared spectroscopy (fNIRS) was used to measure changes of hemoglobin concentrations in prefrontal areas during the verbal fluency task (VFT) before and after stimulation.

RESULTS

After stimulation, iTBS to the left DLPFC with 70% RMT maintained the concentration change of oxyhemoglobin (HbO) in the target area during the VFT. In contrast, 50% [t ₍₁₇₎ = 2.203, P = 0.042, d = 0.523] and 100% iTBS [t ₍₁₇₎ = 2.947, P = 0.009, d = 0.547] significantly decreased change of HbO concentration, indicating an inverse U-shape relationship between stimulation intensity and prefrontal hemodynamic response in healthy young adults. Notably, improved VFT performance was only observed after 70% RMT stimulation [t ₍₁₇₎ = 2.511, P = 0.022, d = 0.592]. Moreover, a significant positive correlation was observed between task performance and the difference in HbO concentration change in the targeted area after 70% RMT stimulation (r = 0.496, P = 0.036) but not after 50 or 100% RMT stimulation.

CONCLUSION

The linear relationship between stimulation intensity and behavioral outcomes reported in previous conventional rTMS studies may not be translated to iTBS. Instead, iTBS at 70% RMT may be more efficacious than 100% RMT.

Depressive and anxiety symptoms are related to decreased lateral prefrontal cortex functioning during cognitive control in older people

Some studies have found a relationship between negative emotional symptoms and decreased lateral PFC functioning during a cognitive control task in healthy younger adults. Here, we asked whether this relationship is also present in the general older population and across different functional domains of the lateral PFC. Thirty-six older people (13 males) self-reported their recent depressive and anxiety symptoms. They also took two cognitive control tasks known to differentially engage the lateral frontoparietal network (digit n-back task) and the lateral frontotemporal network (Category Fluency Test) while hemodynamic changes in the PFC were monitored by functional near-infrared spectroscopy (fNIRS). Both depressive and anxiety symptoms were associated with decreased activation in the bilateral lateral PFC during cognitive control performance. Interestingly, these relationships were driven by the n-back task. Our findings suggest that depressive and anxiety symptoms are related to decreased lateral PFC functioning in particular domains of cognitive control among older people.