Effects of rhythmic auditory stimulation on gait speed in older adult inpatients in a convalescent rehabilitation ward: a pilot randomized controlled trial.

PURPOSE: To assess the impact of gait training with rhythmic auditory stimulation (RAS) on enhancing gait speed in older people admitted to a convalescent rehabilitation ward (CRW), compared to conventional gait training methods. METHODS: The study was designed as a single-center, open-label, pilot, randomized, parallel-group study. Thirty older people admitted to CRW were divided into two groups: the experimental group, which received gait training with RAS (n = 15, females = 53.3%, mean age = 83.9, SD = 6.5), and the control group, which underwent usual gait training (n = 15, females = 60.0%, mean age = 81.3, SD = 8.4). Regardless of their assigned group, all participants underwent 30 min training sessions, five times a week, for 3 weeks. The primary outcome was the 10 m walk test (10mWT), and the secondary outcomes included the Medical Outcome Study 8-Item Short-Form Health Survey and the Japanese version of the modified Gait Efficacy Scale. All measurements were taken at baseline and again at week 3. RESULTS: Results indicated that older people in CRWs in the experimental group showed significant improvements in their 10mWT (effect size - 1.02) compared to the control group. None of the secondary outcomes were significant. CONCLUSIONS: This study suggests the preliminary effectiveness and feasibility of a gait practice intervention using RAS in a CRW. TRIAL REGISTRATION: The University Hospital Medical Information Network (UMIN) Registered 1 October 2022 (UMIN000049089).

Reliability of the Two-dimensional Mood Scale for self-reported mood assessment by older adults with dementia.

The purpose of this study was to evaluate the reliability of the Two-dimensional Mood Scale (TDMS) for mood assessment among older adults with dementia. The study included 100 elderly patients with dementia admitted to two hospitals. For each mood state measured by the TDMS, the intraclass correlation coefficient of agreement (ICCagreement) was calculated to evaluate test-retest reliability. Scores corresponding to the minimal detectable change (MDC) in each mood state at the individual level (MDCind) was also calculated to evaluate measurement error, while McDonald's omega was calculated to evaluate internal consistency. The TDMS ICC was 0.54 for vitality, 0.74 for stability, 0.70 for pleasure, and 0.55 for arousal. The MDCind was 6.89 for vitality, 5.88 for stability, 9.96 for pleasure, and 4.11 for arousal. McDonald's omega ranged from 0.60 to 0.84. The TDMS has generally acceptable reliability for the self-assessment of mood states by older adults with dementia.

Cutoff values of motor and cognitive measures for predicting and discriminating levels of activities of daily living after stroke: a scoping review.

The various assessments performed by rehabilitation professionals not only indicate the patient's current functional status but can also help determine the future status (prediction) or the ability to perform untested tasks (discrimination). In particular, the cutoff values are the simplest predictive and discriminative tool that can be widely used in clinical practice. The purpose of this scoping review was to summarize the current literature on cutoff values of motor and cognitive function for predicting or discriminating levels of activities of daily living after stroke. A literature search was conducted using the PubMed, CINAHL, and Scopus databases. The creation of the search criteria, primary screening of titles and abstract, and secondary screening by full-text review were performed by two rehabilitation professionals. A total of 54 articles were included. The summary of the cutoff values for prediction based on longitudinal studies revealed that an NIHSS score ≤8 and mRMI score ≥19 at acute hospitalization can predict good functional independence and walking independence, respectively, indicating reliable cutoff values. Cutoff values for predicting specific ADLs, such as toilet use or dressing, were not reported, which was a potential research gap identified in this review. Alternatively, the summary of the cutoff values for discrimination based on cross-sectional studies revealed that 288-367.5 m on the 6-min walk test and 25.5-27.6 points on the FMA-LL can discriminate community and noncommunity walkers. Considering the difference between prediction and discrimination, the reliable predicted cutoff values revealed in this review are useful for planning an intervention based on early prediction. Conversely, cutoff values for discrimination can estimate different performances with simpler test, or use as target values during rehabilitation.

Escalation on Kihon Checklist Scores Preceding the Certification of Long-Term Care Need in the Older Population in Japan. A 9-Year Retrospective Study.

Objectives: The Kihon Checklist (KCL) is valuable for predicting long-term care (LTC) certification. However, the precise association between KCL scores and the temporal dynamics of LTC need certification remains unclear. This study clarified the characteristic trajectory of KCL scores in individuals certified for LTC need. Methods: The KCL scores spanning from 2011 to 2019 were obtained from 5630 older individuals, including those certified for LTC need in November 2020, in Iiyama City, Nagano, Japan. We analyzed the KCL score trajectories using a linear mixed model, both before and after propensity score matching. Results: Throughout the 9-year observation period, the KCL scores consistently remained higher in the certified group compared to the non-certified group. Notably, a significant score increase occurred within the 3 years preceding LTC certification. Discussion: Our findings highlight the effectiveness of continuous surveillance using the KCL in identifying individuals likely to require LTC within a few years.

Fine Motor Skills, a Surrogate of Motor Planning Ability, at Age 2 Predict Social Skills at Age 6.

OBJECTIVES: Motor planning is the cognitive process of planning necessary steps for achieving a purposeful movement and is specifically reflected through object manipulation. This study aimed to investigate whether fine motor skills, a surrogate of the motor planning ability of object manipulation, in early childhood are associated with later social skills, in a general-population birth cohort. METHODS: A total of 913 children, participating in the Hamamatsu Birth Cohort for Mothers and Children, were enrolled. Social skills were measured using the Vineland Adaptive Behavior Scales-II, Socialization domain, at age 6 years. Fine motor skills were measured using the Mullen Scales of Early Learning at 14, 24, and 32 months. The associations between fine motor skills at ages 14, 24, and 32 months and social skills at age 6 years were tested separately through multivariable linear regression after adjusting for covariates, including gross motor and language skills at the contemporaneous age, autistic symptoms at age 6 years, and demographic factors. RESULTS: Fine motor skills at 24 and 32 months were significantly associated with social skills at age 6 years (at 24 months: nonstandardized regression coefficient = 1.38 [95% CI, 0.50-2.26], p = 0.002; at 32 months: 1.47 [0.56-2.38], p = 0.001). CONCLUSION: Fine motor skills in early childhood predicted social skills at age 6 years, indicating an association between the complex motor planning ability of object manipulation and later social skills. Children who demonstrate fine motor delay at as early an age as 2 years should be closely monitored by child professionals.

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.

Interleukin-23 levels in umbilical cord blood are associated with neurodevelopmental trajectories in infancy.

Our previous study, which aimed to understand the early neurodevelopmental trajectories of children with and without neurodevelopmental disorders, identified five classes of early neurodevelopmental trajectories, categorized as high normal, normal, low normal, delayed, and markedly delayed. This investigation involved measurement using the Mullen Scale of Early Learning in a representative sample of Japanese infants followed up from the age of 0 to 2 years (Nishimura et al., 2016). In the present study, we investigated the potential association between cytokine concentrations in umbilical cord serum with any of the five classes of neurodevelopmental trajectories previously assigned, as follows: high normal (N = 85, 13.0%), normal (N = 322, 49.1%), low normal (N = 137, 20.9%), delayed (N = 87, 13.3%), and markedly delayed (N = 25, 3.8%) in infancy. Decreased interleukin (IL)-23 levels in the cord blood were associated with the markedly delayed class, independent of potential confounders (odds ratio, 0.44; 95%confidence interval: 0.26-0.73). Furthermore, IL-23 levels decreased as the developmental trajectory became more delayed, demonstrating that IL-23 plays an important role in development, and is useful for predicting the developmental trajectory at birth.

Vertical eDNA distribution of cold-water fishes in response to environmental variables in stratified lake.

In summer, the survival zones of cold-water species are predicted to narrow by both increasing water temperatures from the surface and by expanding hypoxic zones from the lake bottom. To examine how the abundance of cold-water fishes changes along environmental gradients, we assessed the vertical environmental DNA (eDNA) distributions of three salmonid species which may have different water temperature tolerances during both stratification and turnover periods using quantitative PCR (qPCR). In addition, we examined on the vertical distribution of diverse fish fauna using an eDNA metabarcoding assay. The results suggested that the kokanee salmon (Oncorhynchus nerka) eDNA were abundant in deep, cold waters. On the other hand, rainbow trout (O. mykiss) eDNA were distributed uniformly throughout the water column, suggesting that they may have high water-temperature tolerance compared with kokanee salmon. The eDNA concentrations of masu salmon (O. masou) were below the detection limit (i.e., <10 copies µL-1) at all stations and depths and hence could not be quantified during stratification. Together with the finding that the eDNA distributions of other prey fish species were also constrained vertically in species-specific ways, our results suggest that climate change will result in substantial changes in the vertical distributions of lake fish species and thus affect their populations and interactions.

Virus-prokaryote infection pairs associated with prokaryotic production in a freshwater lake.

Viruses infect and kill prokaryotic populations in a density- or frequency-dependent manner and affect carbon cycling. However, the effects of the stratification transition, including the stratified and de-stratified periods, on the changes in prokaryotic and viral communities and their interactions remain unclear. We conducted a monthly survey of the surface and deep layers of a large and deep freshwater lake (Lake Biwa, Japan) for a year and analyzed the prokaryotic production and prokaryotic and viral community composition. Our analysis revealed that, in the surface layer, 19 prokaryotic species, accounting for approximately 40% of the total prokaryotic abundance, could potentially contribute to the majority of prokaryotic production, which is the highest during the summer and is suppressed by viruses. This suggests that a small fraction of prokaryotes and phages were the key infection pairs during the peak period of prokaryotic activity in the freshwater lake. We also found that approximately 50% of the dominant prokaryotic and viral species in the deep layer were present throughout the study period. This suggests that the "kill the winner" model could explain the viral impact on prokaryotes in the surface layer, but other dynamics may be at play in the deep layer. Furthermore, we found that annual vertical mixing could result in a similar rate of community change between the surface and deep layers. These findings may be valuable in understanding how communities and the interaction among them change when freshwater lake stratification is affected by global warming in the future.IMPORTANCEViral infection associated with prokaryotic production occurs in a density- or frequency-dependent manner and regulates the prokaryotic community. Stratification transition and annual vertical mixing in freshwater lakes are known to affect the prokaryotic community and the interaction between prokaryotes and viruses. By pairing measurements of virome analysis and prokaryotic production of a 1-year survey of the depths of surface and deep layers, we revealed (i) the prokaryotic infection pairs associated with prokaryotic production and (ii) the reset in prokaryotic and viral communities through annual vertical mixing in a freshwater lake. Our results provide a basis for future work into changes in stratification that may impact the biogeochemical cycling in freshwater lakes.

The Population-Attributable Fractions of Small-for-Gestational-Age Births: Results from the Japan Birth Cohort Consortium.

A fetal growth restriction is related to adverse child outcomes. We investigated risk ratios and population-attributable fractions (PAF) of small-for-gestational-age (SGA) infants in the Japanese population. Among 28,838 infants from five ongoing prospective birth cohort studies under the Japan Birth Cohort Consortium, two-stage individual-participant data meta-analyses were conducted to calculate risk ratios and PAFs for SGA in advanced maternal age, pre-pregnancy underweight, and smoking and alcohol consumption during pregnancy. Risk ratio was calculated using modified Poisson analyses with robust variance and PAF was calculated in each cohort, following common analyses protocols. Then, results from each cohort study were combined by meta-analyses using random-effects models to obtain the overall estimate for the Japanese population. In this meta-analysis, an increased risk (risk ratio, [95% confidence interval of SGA]) was significantly associated with pre-pregnancy underweight (1.72 [1.42-2.09]), gestational weight gain (1.95 [1.61-2.38]), and continued smoking during pregnancy (1.59 [1.01-2.50]). PAF of underweight, inadequate gestational weight gain, and continued smoking during pregnancy was 10.0% [4.6-15.1%], 31.4% [22.1-39.6%], and 3.2% [-4.8-10.5%], respectively. In conclusion, maternal weight status was a major contributor to SGA births in Japan. Improving maternal weight status should be prioritized to prevent fetal growth restriction.

The association between social camouflage and mental health among autistic people in Japan and the UK: a cross-cultural study.

BACKGROUND: To examine the relationship between social camouflage and mental health in Japanese autistic adults and make an international comparison with a sample from the UK. METHODS: This study analysed secondary data of participants with a self-reported diagnosis of autism from Japan (N = 210; 123 men and 87 women) and the UK (N = 305; 181 women, 104, men, and 18 nonbinary). The relationships between the quadratic term of the Camouflaging Autistic Traits Questionnaire and mental health scales, including depression and anxiety, were assessed. RESULTS: The UK sample showed linear relationships, whereas the Japanese sample showed significant nonlinear relationships. The quadratic terms of the Camouflaging Autistic Traits Questionnaire slightly explained generalised anxiety (ß = .168, p = .007), depression (ß = .121, p = .045), and well-being (ß = - .127, p = .028). However, they did not explain the association between social anxiety and the Camouflaging Autistic Traits Questionnaire. LIMITATIONS: Participants had self-reported diagnoses, and while the autism-spectrum quotient provides a cut-off value for screening, it does not enable confirming diagnoses. Mean scores of the Japanese version of the Camouflaging Autistic Traits Questionnaire were lower as compared to the original CAT-Q, which implies that the social camouflage strategy types used by autistic people in Japan and the UK could differ. The cross-sectional design limits causal inferences. CONCLUSION: In the UK, more social camouflage was associated with poorer mental health scores, whereas too little or too much social camouflage was associated with a low mental health score in Japan. The Japanese population is seemingly less aware of and educated on autistic characteristics and considers 'average' behaviour a good thing. This could influence Japanese autistic people's social camouflage use, differing from that of autistic people in the UK. The differences in the relationship between social camouflage and mental health between Japan and the UK could be associated with national-level divergence regarding the culture of autism.

Autism symptoms, functional impairments, and gaze fixation measured using an eye-tracker in 6-year-old children.

Introduction: Autism spectrum disorder (ASD) is a neurodevelopmental disorder clinically characterized by abnormalities in eye contact during social exchanges. We aimed to clarify whether the amount of gaze fixation, measured at the age of 6 years using Gazefinder, which is an established eye-tracking device, is associated with ASD symptoms and functioning. Methods: The current study included 742 participants from the Hamamatsu Birth Cohort Study. Autistic symptoms were evaluated according to the Autism Diagnostic Observation Schedule, Second Edition (ADOS-2), and the functioning of the participating children in real life was assessed using the Japanese version of the Vineland Adaptive Behavior Scales, Second Edition (VABS-II). The Gazefinder system was used for gaze fixation rates; two areas of interest (eyes and mouth) were defined in a talking movie clip, and eye gaze positions were calculated through corneal reflection techniques. Results: The participants had an average age of 6.06 ± 0.14 years (males: 384; 52%). According to ADOS, 617 (83%) children were assessed as having none/mild ASD and 51 (7%) as severe. The average VABS-II scores were approximately 100 (standard deviation = 12). A higher gaze fixation rate on the eyes was associated with a significantly lower likelihood of the child being assigned to the severe ADOS group after controlling for covariates (odds ratio [OR], 0.02; 95% confidence interval [CI], 0.002-0.38). The gaze fixation rate on the mouth was not associated with ASD symptoms. A higher gaze fixation rate on the mouth was associated with a significantly lower likelihood of the child being assigned to the low score group in VABS-II socialization after controlling for covariates (OR, 0.18; 95% CI, 0.04-0.85). The gaze fixation rate on the eyes was not associated with functioning. Conclusion: We found that children with low gaze fixation rates on the eyes were likely to have more ASD symptoms, and children with low gaze fixation rates on the mouth were likely to demonstrate poorer functioning in socialization. Hence, preschool children could be independently assessed in the general population for clinically relevant endophenotypes predictive of ASD symptoms and functional impairments.

Screen Time at Age 1 Year and Communication and Problem-Solving Developmental Delay at 2 and 4 Years.

Importance: Whether some domains of child development are specifically associated with screen time and whether the association continues with age remain unknown. Objective: To examine the association between screen time exposure among children aged 1 year and 5 domains of developmental delay (communication, gross motor, fine motor, problem-solving, and personal and social skills) at age 2 and 4 years. Design, Participants, and Setting: This cohort study was conducted under the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study. Pregnant women at 50 obstetric clinics and hospitals in the Miyagi and Iwate prefectures in Japan were recruited into the study between July 2013 and March 2017. The information was collected prospectively, and 7097 mother-child pairs were included in the analysis. Data analysis was performed on March 20, 2023. Exposure: Four categories of screen time exposure were identified for children aged 1 year (<1, 1 to <2, 2 to <4, or ≥4 h/d). Main Outcomes and Measures: Developmental delays in the 5 domains for children aged 2 and 4 years were assessed using the Japanese version of the Ages & Stages Questionnaires, Third Edition. Each domain ranged from 0 to 60 points. Developmental delay was defined if the total score for each domain was less than 2 SDs from its mean score. Results: Of the 7097 children in this study, 3674 were boys (51.8%) and 3423 were girls (48.2%). With regard to screen time exposure per day, 3440 children (48.5%) had less than 1 hour, 2095 (29.5%) had 1 to less than 2 hours, 1272 (17.9%) had 2 to less than 4 hours, and 290 (4.1%) had 4 or more hours. Children's screen time was associated with a higher risk of developmental delay at age 2 years in the communication (odds ratio [OR], 1.61 [95% CI, 1.23-2.10] for 1 to <2 h/d; 2.04 [1.52-2.74] for 2 to <4 h/d; 4.78 [3.24-7.06] for ≥4 vs <1 h/d), fine motor (1.74 [1.09-2.79] for ≥4 vs <1 h/d), problem-solving (1.40 [1.02-1.92] for 2 to <4 h/d; 2.67 [1.72-4.14] for ≥4 vs <1 h/d), and personal and social skills (2.10 [1.39-3.18] for ≥4 vs <1 h/d) domains. Regarding risk of developmental delay at age 4 years, associations were identified in the communication (OR, 1.64 [95% CI, 1.20-2.25] for 2 to <4 h/d; 2.68 [1.68-4.27] for ≥4 vs <1 h/d) and problem-solving (1.91 [1.17-3.14] for ≥4 vs <1 h/d) domains. Conclusions and Relevance: In this study, greater screen time for children aged 1 year was associated with developmental delays in communication and problem-solving at ages 2 and 4 years. These findings suggest that domains of developmental delay should be considered separately in future discussions on screen time and child development.

The association between screen time and genetic risks for neurodevelopmental disorders in children.

Whether longer screen time in infancy increases risk of neurodevelopmental disorders (NDDs) such as autism spectrum disorder (ASD) and ADHD has long been debated, but no causal relationship between the two remains has been established. Using ongoing longitudinal cohort data, we found that in children 24 to 40 months of age, the genetic risk of ASD was associated with longer screen time and that of ADHD with an increase in screen time over time. These data suggest that prolonged screen time may not be a cause of the genetic risk for NDD, but an early sign of NDDs.

Immediate Effects of Mobile Phone App for Depressed Mood in Young Adults with Subthreshold Depression: A Pilot Randomized Controlled Trial.

Background: Preventive interventions for subthreshold depression (StD) are essential to reduce the incidence of major depressive disorder. Our smartphone application presenting positive word stimulation in video (ie, Subliminal Priming with Supraliminal Reward Stimulation, SPSRS) was suggested to improve depressive symptoms in people with StD, although it is unclear whether it can immediately improve depressed mood. This pilot randomized controlled trial (RCT) aimed to investigate the preliminary efficacy of SPSRS application intervention on depressive mood in people with StD. Methods: Thirty-two participants with StD were randomly assigned to the experimental (n = 16) or control group (n = 16). The experimental group received SPSRS application intervention (10-minute video with positive word stimulation) and the control group received YouTube application intervention (10-minute video without positive word stimulation). Both groups used identical iPhones managed by the research team. The primary outcome was the change from baseline in depression-dejection on the Profile of Mood States 2nd Edition-Adult Short (POMS 2-A Short) after the intervention. Results: No participants dropped out of the study. The experimental group showed a small improvement in depression-dejection on the POMS 2-A Short score (adjusted Hedges's g = -0.32) compared to the control group. Post-hoc power analyses estimated a sample size of 56 per group (112 total) to evaluate depression-dejection on the POMS 2-A Short in a future full-scale RCT. Conclusion: SPSRS application intervention may be effective in immediately improving depressive mood in people with StD. A future full-scale RCT based on a formally calculated sample size should be conducted to replicate these findings.

Assessing the Smallest Detectable Change of the Kessler Psychological Distress Scale Score in an Adult Population in Japan.

Background: Psychological distress is prevalent worldwide and can lead to the development of mental conditions such as major depression and anxiety disorders. It is essential to assess the severity of patient-reported outcomes to provide effective treatment for psychological distress. The Kessler Psychological Distress Scale (K6) is one of the most widely used psychological distress scales. However, the smallest detectable change (SDC) of the K6 score has not been elucidated. Therefore, the current study aimed to determine the SDC of the K6 score in a Japanese adult population. Methods: Participants aged 20-59 years who are native Japanese speakers were recruited from the panel list of a web research firm. The K6 score was assessed at baseline (T1) and at 2-week follow-up (T2). SDCs were calculated at the individual (SDCind) and group (SDCgroup) levels. Intraclass correlation coefficient agreement (ICCagreement) was calculated to assess test-retest reliability and Cronbach's alpha to evaluate internal consistency. Results: A total of 3254 (1627 [50%] female) responded at T1 and T2. The mean (standard deviation) K6 scores were 5.71 (5.84) at T1 and 5.65 (5.83) at T2. The SDCind and SDCgroup of the K6 score were 8.47 (35.31%) and 0.15 (0.63%), respectively. The ICCagreement was 0.73, and the Cronbach's alpha was 0.94. Conclusion: Our study provided evidence on the reliability and interpretation of the K6 score. Calculating the SDC of the K6 score can help identify the significance of changes in psychological distress over time and can determine the efficacy of interventions for psychological distress.

Child Developmental MRI (CDM) project: protocol for a multi-centre, cross-sectional study on elucidating the pathophysiology of attention-deficit/hyperactivity disorder and autism spectrum disorder through a multi-dimensional approach.

INTRODUCTION: Neuroimaging studies on attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) have demonstrated differences in extensive brain structure, activity and network. However, there remains heterogeneity and inconsistency across these findings, presumably because of the diversity of the disorders themselves, small sample sizes, and site and parameter differences in MRI scanners, and their overall pathogenesis remains unclear. To address these gaps in the literature, we will apply the travelling-subject approach to correct site differences in MRI scanners and clarify brain structure and network characteristics of children with ADHD and ASD using large samples collected in a multi-centre collaboration. In addition, we will investigate the relationship between these characteristics and genetic, epigenetic, biochemical markers, and behavioural and psychological measures. METHODS AND ANALYSIS: We will collect resting-state functional MRI (fMRI) and T1-weighted and diffusion-weighted MRI data from 15 healthy adults as travelling subjects and 300 children (ADHD, n=100; ASD, n=100; and typical development, n=100) with multi-dimensional assessments. We will also apply data from more than 1000 samples acquired in our previous neuroimaging studies on ADHD and ASD. ETHICS AND DISSEMINATION: The study protocol has been approved by the Research Ethics Committee of the University of Fukui Hospital (approval no: 20220601). Our study findings will be submitted to scientific peer-reviewed journals and conferences.

Interaction of genetic liability for attention deficit hyperactivity disorder (ADHD) and perinatal inflammation contributes to ADHD symptoms in children.

Objective: Genetic and environmental factors contribute to the development of Attention Deficit/Hyperactivity Disorder (ADHD). Perinatal inflammation is one of the promising environmental risk factors for ADHD, but the relationship between the genetic risk for ADHD and perinatal inflammation requires further examination. Methods: A possible gene-environmental interaction between perinatal inflammation and ADHD polygenic risk score (ADHD-PRS) on ADHD symptoms was investigated in children aged 8-9 from the Hamamatsu Birth Cohort for Mothers and Children (N = 531). Perinatal inflammation was evaluated by the level of concentration of three cytokines assayed in umbilical cord blood. The genetic risk for ADHD was assessed by calculating ADHD-PRS for each individual using a previously collected genome-wide association study of ADHD. Results: Perinatal inflammation (ß [SE], 0.263 [0.017]; P < 0.001), ADHD-PRS (ß [SE], 0.116[0.042]; P = 0.006), and an interaction between the two (ß [SE], 0.031[0.011]; P = 0.010) were associated with ADHD symptoms. The association between perinatal inflammation and ADHD symptoms measured by ADHD-PRS was evident only in the two higher genetic risk groups (ß [SE], 0.623[0.122]; P < 0.001 for the medium-high risk group; ß [SE], 0.664[0.152]; P < 0.001 for the high-risk group). Conclusion: Inflammation in the perinatal period both directly elevated ADHD symptoms and magnified the impact of genetic vulnerability on ADHD risk particularly among children aged 8-9 with genetically higher risk for ADHD.