Photobiomodulation may enhance cognitive efficiency in older adults: a functional near-infrared spectroscopy study.

Introduction: The relative oxygenated hemoglobin (HbO) measured using functional near-infrared spectroscopy (fNIRS) has been considered as an index for cognitive loading, with the more difficult the task, the higher the level. A previous study reported that young adults who received transcranial photobiomodulation (tPBM) showed a reduced HbO of a difficult task, suggesting that tPBM may enhance cognitive efficiency. The present study further investigated the effect of tPBM on cognitive efficiency in older adults. Methods: Thirty participants received a single tPBM on the forehead for 350 s. Before and after tPBM, their HbO in the visual span task with various difficulties was measured with fNIRS. Results: After tPBM, participants exhibited significantly lower HbO in a harder (span 7) but not an easier level (span 2) of the task, but their behavioral performance remained unchanged. In addition, factors affecting the reduction of HbO were examined, and the results showed that individuals with better memory (as measured by a 30-min delayed recall test) showed more reduction of HbO. Discussion: The results suggest that tPBM may enhance cognitive efficiency, with individuals with better memory tend to benefit more.

Prefrontal hemodynamic features of older adults with preserved visuospatial working memory function.

Memory decline has been observed in the aging population and is a risk factor for the later development of dementia. Understanding how memory is preserved in older adults has been an important topic. The present study examines the hemodynamic features of older adults whose memory is comparable with that of young adults. In the present study, 45 younger and 45 older adults performed the visual memory task with various difficulty levels (i.e., the items to be remembered), and their cerebral hemodynamics at each level were measured by functional near-infrared spectroscopy (fNIRS). The results showed that older adults exhibited higher activation than younger adults under more difficult but not easier levels. In addition, older adults whose performance is comparable with that of young adults (i.e., being able to remember six items) showed more right-lateralized activation. However, those unable to do so showed more left-lateralized activation. The results suggested that high-performing older adults possess successful compensatory mechanisms by recruiting cognitive resources in a specialized brain region.

Temporal processing deficit in children and adolescents with autism spectrum disorder: An online assessment.

Objective: The sensory deficit has been considered as one of the core features in children and adolescents with autism spectrum disorder (ASD). The present study aimed to examine the temporal processing of simple and more complex auditory inputs in ASD children and adolescents with an online assessment that can be conducted remotely. Methods: One hundred fifty-eight children and adolescents aged 5-17 years participated in this study, including 79 ASD participants and 79 typically developing (TD) participants. The online assessment consisted of two temporal-order judgment tasks that required repeating the sequence of two pure tones or consonant-vowel (CV) syllabic pairs at varying interstimulus intervals (ISIs). Results: Significantly lower accuracy rates were found in ASD than TD participants in the pure tone and the CV conditions with both short and long ISI. In addition, ASD participants (M = 245.97 ms) showed a significantly higher passing threshold than TD participants (M = 178.84 ms) in the CV task. Receiver operating characteristic analysis found that the age × ISI passing threshold composite yielded a sensitivity of 74.7% and a specificity of 50.6% at the cutoff point of -0.307 in differentiating ASD participants from TD participants. Conclusion: In sum, children and adolescents with ASD showed impaired temporal processing of both simple and more complex auditory stimuli, and the online assessment seems to be sensitive in differentiating individuals with ASD from those with TD.

Effectiveness of lifestyle medicine on cognitive functions in mild cognitive impairments and dementia: A systematic review on randomized controlled trials.

Mild cognitive impairment (MCI) and dementia are associated with lifestyle risk factors, making lifestyle medicine a potentially viable intervention for people with MCI and dementia. The present study aims to examine the effectiveness of lifestyle medicine on cognitive functions among people with MCI and dementia, by performing a systematic review and meta-analysis on randomized controlled trials (RCT). A systematic literature search was conducted to extract RCTs adopting lifestyle interventions of diet, exercise, and stress management or emotional well-being. Results showed that 65 studies were eligible. Exercise was the most promising lifestyle intervention that improved various cognitive functions among people with MCI and dementia, and was more effective in MCI than in dementia. Interventions on stress management or emotional well-being did not show a significant effect on people with MCI, and the evidence for people with dementia was insufficient to conclude. Similarly, due to the lack of RCTs on a healthy dietary pattern, the effectiveness of diet interventions was not examined. In conclusion, the exercise component of lifestyle medicine can be an effective and clinically significant intervention for protecting people with MCI and dementia against cognitive declines, especially when served as an early intervention at the stage of MCI.

Can transcranial photobiomodulation improve cognitive function? A systematic review of human studies.

BACKGROUND: Transcranial photobiomodulation (tPBM) has been studied for over a decade as a possible cognitive intervention. OBJECTIVE: To evaluate the effect of tPBM for enhancing human cognitive function in healthy adults and remediating impaired cognitive function in adults with cognitive disorders. METHODS: A systematic literature search from three electronic databases (PubMed, Scopus, Web of Science) was conducted from 1987 to May 2022. The cognitive function being evaluated included learning and memory, attention, executive function, language, and global cognitive function. RESULTS: Of the 35 studies identified, 29 (82.9 %) studies reported positive improvement in cognitive functions after tPBM. All nine studies on participants with subjective memory complaints, mild cognitive impairment, and dementia, showed positive outcomes. Seven (87.5 %) studies on traumatic brain injury (TBI) patients also showed positive results. A series of clinical trials on stroke patients showed positive trends on improved neurological deficit at first, but was prematurely terminated later at phase III due to the lack of statistical significance. One of the most common protocols for clinical populations employed devices delivering near-infrared light (810 nm), the irradiance of 20-25 mW/cm2, and fluence of 1-10 J/cm2. While this was common, the reviewed protocols also included other wavelengths of light ranging from visible, red (630-635 nm) to invisible near-infrared maximum wavelengths of 1060-1068 nm. CONCLUSIONS: tPBM seems to improve cognitive function. However, only half of the reviewed clinical trials were randomized control trials, further investigation is warranted.

Temporal processing deficit in children with attention-deficit/hyperactivity disorder: An online assessment.

Objective: Temporal processing deficits were found among children with attention-deficit/hyperactivity disorder (ADHD). The present study aims to develop an online temporal processing assessment that can be conducted remotely, and the sensitivity of the test was assessed on a group of children with ADHD. Methods: A total of 188 children were recruited, including 94 typically developing (TD) children, and 94 children with ADHD. The online assessment consists of two temporal-order judgment (TOJ) tasks. One task used tone pairs presented with two interstimulus intervals (ISIs) (305ms and 40ms). Another task used pairs of consonant-vowel (CV) syllables with 20 varying ISI levels. Participants were asked to determine the sequence of the sound pairs. Results: The results showed that ADHD children were less accurate (ISI 305ms: M = 83.90%; ISI 40ms: M = 66.28%) than TD children (ISI 305ms: M = 89.36%; ISI 40ms: M = 77.16%) in the tone task. Similarly, ADHD children showed a higher ISI passing threshold (M = 283.64ms) than TD children (M = 199.76ms) and higher accuracy in the CV task. Hierarchical binary logistic regression suggested a model to predict ADHD children using accuracy in ISI 40ms in the tone task and ISI passing threshold in the CV task. Receiver operating characteristic (ROC) analysis yielded a sensitivity of 75.58% and a specificity of 51.11%. Conclusion: ADHD children showed temporal processing deficits of both tones and CVs. The online assessment may be a valid tool for differentiating ADHD children from TD children.

Eye-tracking training improves the learning and memory of children with learning difficulty.

Children who experience difficulty in learning at mainstream schools usually are provided with remediation classes after school to facilitate their learning. The present study aims to evaluate an innovative eye-tracking training as possible alternative remediation. Our previous findings showed that children who received eye-tracking training demonstrated improved attention and inhibitory control, and the present randomized controlled study aims to evaluate if eye-tracking training can also enhance the learning and memory of children. Fifty-three primary school students with learning difficulty (including autism spectrum disorder, attention-deficit/hyperactivity disorder, specific learning disorder, specific language impairment and borderline intellectual functioning) were recruited and randomly assigned to either the Eye-tracking Training group or the after-school remediation class. They were assessed on their learning and memory using the Hong Kong List Learning Test before and after 8-month training. Twenty weekly parallel sessions of training, 50 min per session, were provided to each group. Children who received the eye-tracking training, not those in the control group, showed a significant improvement in memory as measured by the delayed recall. In addition, the Eye-Tracking Training group showed significantly faster learning than the control group. Also, the two groups showed a significant improvement in their reading abilities. In sum, eye-tracking training may be effective training for enhancing the learning and memory of children with learning difficulties.

Digital Cognitive Biomarker for Mild Cognitive Impairments and Dementia: A Systematic Review.

The dementia population is increasing as the world's population is growing older. The current systematic review aims to identify digital cognitive biomarkers from computerized tests for detecting dementia and its risk state of mild cognitive impairment (MCI), and to evaluate the diagnostic performance of digital cognitive biomarkers. A literature search was performed in three databases, and supplemented by a Google search for names of previously identified computerized tests. Computerized tests were categorized into five types, including memory tests, test batteries, other single/multiple cognitive tests, handwriting/drawing tests, and daily living tasks and serious games. Results showed that 78 studies were eligible. Around 90% of the included studies were rated as high quality based on the Newcastle-Ottawa Scale (NOS). Most of the digital cognitive biomarkers achieved comparable or even better diagnostic performance than traditional paper-and-pencil tests. Moderate to large group differences were consistently observed in cognitive outcomes related to memory and executive functions, as well as some novel outcomes measured by handwriting/drawing tests, daily living tasks, and serious games. These outcomes have the potential to be sensitive digital cognitive biomarkers for MCI and dementia. Therefore, digital cognitive biomarkers can be a sensitive and promising clinical tool for detecting MCI and dementia.

Prefrontal Activation During Effortful Processing Differentiates Memory Abilities in Adults with Memory Complaints.

BACKGROUND: Identifying individuals at increased risks for developing Alzheimer's disease (AD) is crucial for early intervention. Memory complaints are associated with brain abnormalities characteristic of AD in cognitively normal older people. However, the utility of memory complaints for predicting mild cognitive impairment (MCI) or AD onset remains controversial, likely due to the heterogeneous nature of this construct. OBJECTIVE: We investigated whether prefrontal oxygenation changes measured by functional near-infrared spectroscopy (fNIRS) during an arduous cognitive task, previously shown to be associated with the AD syndrome, could differentiate memory abilities among individuals with memory complaints. Episodic memory performance was adopted as a proxy for MCI/AD risks since it has been shown to predict AD progression across stages. METHODS: Thirty-six adults self-reporting memory complaints in the absence of memory impairment completed a verbal list learning test and underwent a digit n-back paradigm with an easy (0-back) and a difficult (2-back) condition. K-means clustering was applied to empirically derive memory complaint subgroups based on fNIRS-based prefrontal oxygenation changes during the effortful 2-back task. RESULTS: Cluster analysis revealed two subgroups characterized by high (n = 12) and low (n = 24) bilateral prefrontal activation during the 2-back but not a 0-back task. The low activation group was significantly less accurate across the n-back task and recalled significantly fewer words on the verbal memory test compared to the high activation group. CONCLUSION: fNIRS may have the potential to differentiate verbal memory abilities in individuals with self-reported memory complaints.

Photobiomodulation improves frontal lobe cognitive functions and mental health of older adults with non-amnestic mild cognitive impairment: Case studies.

Introduction: This study investigated the effects of transcranial photobiomodulation (tPBM) on improving the frontal lobe cognitive functions and mental health of older adults. Methods: Three older adults with mild cognitive impairment (MCI) of the non-amnestic type received 18-session tPBM stimulation for 9 weeks and were assessed with neuropsychological tests of memory and executive functions and standardized questionnaires on depressive and anxiety symptoms, global cognitive functions, and daily functioning abilities before and after tPBM stimulation. Results: At baseline, their intrusion and/or perseveration errors in a verbal memory test and a fluency test, as measures of the frontal lobe cognitive functions, were in the borderline to severely impaired range at baseline. After tPBM stimulation, the three older adults showed various levels of improvement in their frontal lobe cognitive functions. One older adult's intrusion and perseveration errors improved from the <1st-2nd percentile (moderately to severely impaired range) to the 41st-69th percentile (average range), another older adult's intrusion errors improved from the 11th percentile to the 83rd percentile, and the third older adult's intrusion errors improved from the 5th percentile to the 56th percentile. Moreover, improvements in their anxiety and/or depressive symptoms were also observed. One older adult's depressive and anxiety symptoms improved from the severe range at baseline to the mild range after the intervention. The other two older adults' depressive symptoms improved from the mild range at baseline to the normal range after the intervention. Discussion: These findings provide preliminary support for the potential of tPBM to improve the frontal lobe cognitive functions and mental health of older adults with MCI. Given the small sample size of only three older adults and the absence of a placebo control group, larger randomized controlled studies are needed to confirm its potential.

Photoneuromodulation makes a difficult cognitive task less arduous.

A positive effect of photoneuromodulation (PNM) has been found on cognitive and emotional functions in healthy populations. However, the hemodynamic changes associated with improved cognitive functions (i.e., memory and executive functions) are unexplored. Therefore, the present study investigated the hemodynamic changes associated with PNM using functional near-infrared spectroscopy (fNIRS). In this experiment, 33 young healthy adults were recruited and randomly assigned to control and experimental groups. A single PNM stimulation was applied to the forehead in the experimental group, while a sham stimulation (same procedure without machine activation) was performed for the control group. Before and after the stimulation, all participants performed an n-back task with 0-and 3-back conditions to assess their working memory function, and their hemodynamic responses during the tasks were measured by fNIRS. A significant group (experimental vs. control) × time (before vs. after PNM) interaction in memory-related frontal activation was found. Specifically, only the experimental group had a significant reduction in frontal hemodynamic levels during the difficult task. Additionally, the memory-related frontal activation was significantly correlated with the immediate and delayed recall of the Rey-Osterrieth Complex Figure Test assessed at baseline. Therefore, PNM may reduce the cognitive efforts needed to complete tasks with high memory loads.

Photobiomodulation Enhances Memory Processing in Older Adults with Mild Cognitive Impairment: A Functional Near-Infrared Spectroscopy Study.

BACKGROUND: Recent studies of photobiomodulation (PBM) in patients with cognitive or psychological disorders (including traumatic brain injury, stroke, and dementia) have yielded some encouraging results. OBJECTIVE: In this study, we aimed to investigate the effect of a single stimulation on memory in older adults with mild cognitive impairment (MCI). METHODS: After PBM, hemodynamic changes, as a measure of functional brain activity, were evaluated using functional near-infrared spectroscopy (fNIRS). Eighteen subjects who met the criteria of MCI were randomly assigned to control and experimental groups. A single real or sham PBM session was administered to the forehead of each patient in the experimental and control groups, respectively. All subjects performed a visual memory span test before and after the stimulation, and their hemodynamic responses during the tasks were measured using fNIRS. RESULTS: The results showed that among the MCI subjects, only those who received PBM, but not those who received the sham stimulation, demonstrated significant improvement in the visual memory performance and a reduction in the hemodynamic response during the tasks. CONCLUSION: These findings suggest that PBM may reduce the cognitive efforts needed to complete tasks that require high memory loads, and thus improve the cognitive performance of individuals with MCI.

Eye-Tracking Training Improves Inhibitory Control in Children with Attention-Deficit/Hyperactivity Disorder.

Disinhibition is a common sign among children with attention-deficit/hyperactivity disorder (ADHD). The present study examined the effect of computerized eye-tracking training to improve inhibitory control in ADHD children. Thirty-two ADHD children (mean age = 8.4 years) were recruited. Half of the participants underwent 240 min of eye-tracking training over two weeks (i.e., experimental group), while the other half did not receive any training (i.e., control group). After training, the experimental group exhibited significant improvements in neuropsychological tests of inhibition, such as faster reaction time in the incongruent condition of the Flanker test, more unique designs in the Category Fluency and Five-Point Tests, and a faster completion time in Trail 2 of the Children's Color Trail Test. The control group did not show significant changes in any of these tests. Our findings support the use of eye-tracking training to improve the inhibitory control of ADHD children.

Computerized Eye-Tracking Training Improves the Saccadic Eye Movements of Children with Attention-Deficit/Hyperactivity Disorder.

Abnormal saccadic eye movements, such as longer anti-saccade latency and lower pro-saccade accuracy, are common in children with attention-deficit/hyperactivity disorder (ADHD). The present study aimed to investigate the effectiveness of computerized eye-tracking training on improving saccadic eye movements in children with ADHD. Eighteen children with ADHD (mean age = 8.8 years, 10 males) were recruited and assigned to either the experimental (n = 9) or control group (n = 9). The experimental group underwent an accumulated 240 min of eye-tracking training within two weeks, whereas the control group engaged in web game playing for the same amount of time. Saccadic performances were assessed using the anti- and pro-saccade tasks before and after training. Compared to the baseline, only the children who underwent the eye-tracking training showed significant improvements in saccade latency and accuracy in the anti- and pro-saccade tasks, respectively. In contrast, the control group exhibited no significant changes. These preliminary findings support the use of eye-tracking training as a safe non-pharmacological intervention for improving the saccadic eye movements of children with ADHD.

Photobiomodulation improves the frontal cognitive function of older adults.

OBJECTIVES: The frontal lobe hypothesis of age-related cognitive decline suggests that the deterioration of the prefrontal cortical regions that occurs with aging leads to executive function deficits. Photobiomodulation (PBM) is a newly developed, noninvasive technique for enhancing brain function, which has shown promising effects on cognitive function in both animals and humans. This randomized, sham-controlled study sought to examine the effects of PBM on the frontal brain function of older adults. METHODS/DESIGNS: Thirty older adults without a neuropsychiatric history performed cognitive tests of frontal function (ie, the Eriksen flanker and category fluency tests) before and after a single 7.5-minute session of real or sham PBM. The PBM device consisted of three separate light-emitting diode cluster heads (633 and 870 nm), which were applied to both sides of the forehead and posterior midline, and delivered a total energy of 1349 J. RESULTS: Significant group (experimental, control) × time (pre-PBM, post-PBM) interactions were found for the flanker and category fluency test scores. Specifically, only the older adults who received real PBM exhibited significant improvements in their action selection, inhibition ability, and mental flexibility after vs before PBM. CONCLUSIONS: Our findings support that PBM may enhance the frontal brain functions of older adults in a safe and cost-effective manner.

Sustained Effects of Memory and Lifestyle Interventions on Memory Functioning of Older Adults: An 18-Month Follow-Up Study.

Background: There has been much research devoted to examining the short-term effects of different interventions for improving memory functioning of older adults with memory complaints. Nevertheless, very few studies have examined the long-term effects of these interventions. Thus, the present study compared the sustained effects of a conventional memory intervention (MI) and a Chinese lifestyle intervention on improving memory functioning in older adults. Methods: Twenty-nine older adults who were aged 60 years and older and had memory complaints were recruited. Each completed 10 weekly sessions of the Dejian Mind-body Intervention (DMBI; n = 11) or MI (n = 18) approximately 18 months ago. Participants' verbal and visual memory functioning and their subjective impression of the changes of their memory performance and physical and psychological health status were evaluated. Results: Results showed significant improvements in memory in both intervention groups at the follow-up assessments when compared with baseline. In addition, older adults in both intervention groups perceived improved memory performance and physical and psychological wellness at follow-up, with the DMBI group reporting significantly greater improvements in physical health compared to the MI group. Conclusion: Altogether, the present study provides supportive evidence that the DMBI and MI might be two effective remedies for older adults to improve or preserve their memory functioning with relatively sustained effects.

Using a social robot to teach gestural recognition and production in children with autism spectrum disorders.

While it has been argued that children with autism spectrum disorders are responsive to robot-like toys, very little research has examined the impact of robot-based intervention on gesture use. These children have delayed gestural development. We used a social robot in two phases to teach them to recognize and produce eight pantomime gestures that expressed feelings and needs. Compared to the children in the wait-list control group (N = 6), those in the intervention group (N = 7) were more likely to recognize gestures and to gesture accurately in trained and untrained scenarios. They also generalized the acquired recognition (but not production) skills to human-to-human interaction. The benefits and limitations of robot-based intervention for gestural learning were highlighted. Implications for Rehabilitation Compared to typically-developing children, children with autism spectrum disorders have delayed development of gesture comprehension and production. Robot-based intervention program was developed to teach children with autism spectrum disorders recognition (Phase I) and production (Phase II) of eight pantomime gestures that expressed feelings and needs. Children in the intervention group (but not in the wait-list control group) were able to recognize more gestures in both trained and untrained scenarios and generalize the acquired gestural recognition skills to human-to-human interaction. Similar findings were reported for gestural production except that there was no strong evidence showing children in the intervention group could produce gestures accurately in human-to-human interaction.