Moment-to-moment affective dynamics in schizophrenia and bipolar disorder.

BACKGROUND: Affective disturbances in schizophrenia and bipolar disorder may represent a transdiagnostic etiological process as well as a target of intervention. Hypotheses on similarities and differences in various parameters of affective dynamics (intensity, successive/acute changes, variability, and reactivity to stress) between the two disorders were tested. METHODS: Experience sampling method was used to assess dynamics of positive and negative affect, 10 times a day over 6 consecutive days. Patients with schizophrenia (n = 46) and patients with bipolar disorder (n = 46) were compared against age-matched healthy controls (n = 46). RESULTS: Compared to controls, the schizophrenia group had significantly more intense momentary negative affect, a lower likelihood of acute changes in positive affect, and reduced within-person variability of positive affect. The bipolar disorder group was not significantly different from either the schizophrenia group or the healthy control group on any affect indexes. Within the schizophrenia group, level of depression was associated with weaker reactivity to stress for negative affect. Within the bipolar disorder group, level of depression was associated with lower positive affect. CONCLUSIONS: Patients with schizophrenia endured a more stable and negative affective state than healthy individuals, and were less likely to be uplifted in response to happenings in daily life. There is little evidence that these affective constructs characterize the psychopathology of bipolar disorder; such investigation may have been limited by the heterogeneity within group. Our findings supported the clinical importance of assessing multiple facets of affective dynamics beyond the mean levels of intensity.

Specificity of associations between parental psychopathology and offspring brain structure.

Multiple forms of parental psychopathology have been associated with differences in subcortical brain volume. However, few studies have considered the role of comorbidity. Here, we examine if alterations in child subcortical brain structure are specific to parental depression, anxiety, mania, or alcohol/substance use parental psychopathology, common across these disorders, or altered by a history of multiple disorders. We examined 6581 children aged 9 to 10 years old from the ABCD study with no history of mental disorders. We found several significant interactions such that the effects of a parental history of depression, anxiety, and substance use problems on amygdala and striatal volumes were moderated by comorbid parental history of another disorder. Interactions tended to suggest smaller volumes in the presence of a comorbid disorder. However, effect sizes were small, and no associations remained significant after correcting for multiple comparisons. Results suggest that associations between familial risk for psychopathology and offspring brain structure in 9-10-year-olds are modest, and relationships that do exist tend to implicate the amygdala and striatal regions and are moderated by a comorbid parental psychopathology history. Several methodological factors, including controlling for intracranial volume and other forms of parental psychopathology and excluding child psychopathology, likely contribute to inconsistencies in the literature.

A comparison of sleep-wake patterns among school-age children and adolescents in Hong Kong before and during the COVID-19 pandemic.

STUDY OBJECTIVES: The lifestyles change of children and adolescents during the COVID-19 pandemic due to antipandemic measures can affect their sleep health. Existing studies have used convenient samples and focused on the initial months of the pandemic, leaving a knowledge gap on changes in young people's sleep patterns under the "new normal" under COVID-19. METHODS: As part of a territory-wide epidemiological study in Hong Kong, this cross-sectional study recruited primary and secondary school students by stratified random sampling. Sleep parameters were collected using the structured diagnostic interview for sleep patterns and disorders. We investigated the pandemic's effects on sleep parameters by comparing data of participants recruited pre-COVID and those recruited during COVID using multivariate regression, adjusting for age, sex, household income, seasonality, and presence of mental disorders, and the moderators and mediators of the effects. RESULTS: Between September 1, 2019 and June 2, 2021, 791 primary and 442 secondary school students were recruited and analyzed. Primary school and secondary school participants assessed before COVID had a longer sleep latency on school days (95% confidence interval [CI] = 1.0-5.2 minutes, adjusted P-value = .010; and 95% CI= 3.9-13.0 minutes, adjusted P-value = .004, respectively) and nonschool days (95% CI = 1.7-7.2 minutes, adjusted P-value = .005; 95% CI = 3.4-13.7 minutes, adjusted P-value = .014, respectively). Low household income was a moderator for later bedtime (adjusted P-value = .032) and later sleep onset (adjusted P-value = .043) during nonschool days among secondary school students. CONCLUSIONS: Changes associated with COVID have a widespread and enduring effect on the sleep health of school-aged students in Hong Kong. Household income plays a role in adolescent sleep health resilience, and the impact of antiepidemic measures on the health gaps of the youth should be considered. CITATION: Chau SWH, Hussain S, Chan SSM, et al. A comparison of sleep-wake patterns among school-age children and adolescents in Hong Kong before and during the COVID-19 pandemic. J Clin Sleep Med. 2023;19(4):749-757.

Depression duration and risk of incident cardiovascular disease: A population-based six-year cohort study.

BACKGROUND: Depression symptoms are significantly associated with an increased risk of cardiovascular disease (CVD). However, understanding of the magnitude of the association between depression duration and risk of CVD is limited. Therefore, we aimed to assess whether a longer duration of exposure to depression is associated with a higher risk of new-onset CVD. METHODS: We conducted a territory-wide retrospective cohort study among patients (≥ 10 years old) with depression diagnosed between January and December 2014 in Hong Kong. The observation period spanned January 1, 2014, to December 31, 2019, and all participants had no CVD at baseline. Incidence of CVD was calculated. We used Cox proportional hazard regression to adjust confounders and estimate hazard ratios of CVD risk. RESULTS: Among 11,651 participants with depression, 1306 (11.2%) individuals developed CVD. Multi-adjusted models showed individuals with depression duration of 2-5 years (Hazard Ratios [HRs]: 1.38 [95% confidence interval (CI): 1.19-1.60]) and ≥6 years (1.45 [1.25-1.68]) had a significantly escalated risk of developing CVD, compared to those with depression within one year. Stratified analyses indicated that the association was prominent in women and those under 65 years old. LIMITATIONS: Lack of depression severity information and the small sample size in some subgroup analyses. CONCLUSIONS: Longer exposure to depression is associated with significant increased risk of CVD. The interplay between mental and vascular health emphasizes the need for CVD prevention in patients with long-term depression.

Antidepressant efficacy of low-frequency repetitive transcranial magnetic stimulation in antidepressant-nonresponding bipolar depression: a single-blind randomized sham-controlled trial.

BACKGROUND: To examine the antidepressant efficacy and response predictors of R-DLPFC-LF rTMS for antidepressant-nonresponding BD. METHODS: We conducted a single-blind randomized sham-controlled trial for 54 (28 sham, 26 active) patients with antidepressant-nonresponding BD (baseline MADRS ≥ 20). Patients received 15 daily sessions of active or sham neuronavigated rTMS (Figure-of-8 coil, five 1 Hz 60 s 110% RMT trains). Outcome measures included depressive response (≥ 50% MADRS reduction, CGI ≤ 2) and remission (MADRS < 7, CGI = 1) rates, treatment emergent hypo/mania (YMRS), depressive and anxiety symptoms (HAM-A). RESULTS: 48 patients (25 sham, 23 active) completed treatment, with 3 drop-outs each in active and sham groups. Active rTMS did not produce superior response or remission rates at endpoint or 6 or 12 weeks (ps > 0.05). There was no significant group * time interaction (ps > 0.05) in a multivariate ANOVA with MADRS, HAMA and YMRS as dependent variables. Exploratory analysis found MADRS improvement to be moderated by baseline anxiety (p = 0.02) and melancholia (p = 0.03) at week 3, and depressive onset at weeks 6 (p = 0.03) and 12 (p = 0.04). In subjects with below-mean anxiety (HAMA < 20.7, n = 24), MADRS improvement from active rTMS was superior to sham at week 3 (ITT, t = 2.49, p = 0.04, Cohen's d = 1.05). No seizures were observed. Groups did not differ in treatment-emergent hypomania (p = 0.1). LIMITATIONS: Larger sample size might be needed to power subgroup analyses. Moderation analyses were exploratory. Single-blind design. Unblinding before follow-up assessments due to ethical reasons. CONCLUSIONS: 1-Hz 110% RMT (5 × 60 s trains) R-DLPFC-LF rTMS was not effective for antidepressant non-responding BD but may be further investigated at increased dosage and/or in BD patients with low anxiety. Trial registration CCRB Clinical Trials Registry, CUHK, CUHK_CCT00440. Registered 04 December 2014, https://www2.ccrb.cuhk.edu.hk/registry/public/279.

History for some or lesson for all? A systematic review and meta-analysis on the immediate and long-term mental health impact of the 2002-2003 Severe Acute Respiratory Syndrome (SARS) outbreak.

BACKGROUND: The aims of this systematic review and meta-analysis are to examine the prevalence of adverse mental health outcomes, both short-term and long-term, among SARS patients, healthcare workers and the general public of SARS-affected regions, and to examine the protective and risk factors associated with these mental health outcomes. METHODS: We conducted a systematic search of the literature using databases such as Medline, Pubmed, Embase, PsycInfo, Web of Science Core Collection, CNKI, the National Central Library Online Catalog and dissertation databases to identify studies in the English or Chinese language published between January 2003 to May 2020 which reported psychological distress and mental health morbidities among SARS patients, healthcare workers, and the general public in regions with major SARS outbreaks. RESULTS: The literature search yielded 6984 titles. Screening resulted in 80 papers for the review, 35 of which were included in the meta-analysis. The prevalence of post-recovery probable or clinician-diagnosed anxiety disorder, depressive disorder, and post-traumatic stress disorder (PTSD) among SARS survivors were 19, 20 and 28%, respectively. The prevalence of these outcomes among studies conducted within and beyond 6 months post-discharge was not significantly different. Certain aspects of mental health-related quality of life measures among SARS survivors remained impaired beyond 6 months post-discharge. The prevalence of probable depressive disorder and PTSD among healthcare workers post-SARS were 12 and 11%, respectively. The general public had increased anxiety levels during SARS, but whether there was a clinically significant population-wide mental health impact remained inconclusive. Narrative synthesis revealed occupational exposure to SARS patients and perceived stigmatisation to be risk factors for adverse mental health outcomes among healthcare workers, although causality could not be determined due to the limitations of the studies. CONCLUSIONS: The chronicity of psychiatric morbidities among SARS survivors should alert us to the potential long-term mental health complications of covid-19 patients. Healthcare workers working in high-risk venues should be given adequate mental health support. Stigmatisation against patients and healthcare workers should be explored and addressed. The significant risk of bias and high degree of heterogeneity among included studies limited the certainty of the body of evidence of the review.

Functional connectivity of the frontotemporal network in preattentive detection of abstract changes: Perturbs and observes with transcranial magnetic stimulation and event-related optical signal.

Current theories of automatic or preattentive change detection suggest a regularity or prediction violation mechanism involving functional connectivity between the inferior frontal cortex (IFC) and the superior temporal cortex (STC). By disrupting the IFC function with transcranial magnetic stimulation (TMS) and recording the later STC mismatch response with event-related optical signal (EROS), previous study demonstrated a causal IFC-to-STC functional connection in detecting a pitch or physical change. However, physical change detection can be achieved by memory comparison of the physical features and may not necessarily involve regularity/rule extraction and prediction. The current study investigated the IFC-STC functional connectivity in detecting rule violation (i.e., an abstract change). Frequent standard tone pairs with a constant relative pitch difference, but varying pitches, were presented to establish a pitch interval rule. This abstract rule was violated by deviants with reduced relative pitch intervals. The EROS STC mismatch response to the deviants was abolished by the TMS applied at the IFC 80 ms after deviance onset, but preserved in the spatial (TMS on vertex), auditory (TMS sound), and temporal (200 ms after deviance onset) control conditions. These results demonstrate the IFC-STC connection in preattentive abstract change detection and support the regularity or prediction violation account.

10Kin1day: A Bottom-Up Neuroimaging Initiative.

We organized 10Kin1day, a pop-up scientific event with the goal to bring together neuroimaging groups from around the world to jointly analyze 10,000+ existing MRI connectivity datasets during a 3-day workshop. In this report, we describe the motivation and principles of 10Kin1day, together with a public release of 8,000+ MRI connectome maps of the human brain.

Localized Analysis of Normalized Distance from Scalp to Cortex and Personalized Evaluation (LANDSCAPE): Focusing on Age- and Dementia-Specific Changes.

BACKGROUND: Scalp to cortex distance (SCD), as a key technological parameter, has been highlighted in the guidelines of non-invasive brain stimulation. However, in the context of age-related brain changes, the region-specific SCD and its impact on stimulation-induced electric field remain unclear. OBJECTIVE: This study aimed to investigate the region-specific SCD and its relationship with morphometric features and cognitive function in age- and disease-specific populations. METHODS: We analyzed the SCD and cortical thickness (CT) of left primary motor cortex (M1) and dorsolateral prefrontal cortex (DLPFC) in 214 cognitively normal adults and 43 dementia patients. CT-adjusted SCD was used to control the influence of CT on SCD. Head model was developed to simulate the impact of SCD on the electric field induced by transcranial electrical stimulation. RESULTS: We found age-related increased SCD in the left DLPFC (p < 0.001), but not M1 (p = 0.134), and dementia-related increased SCD in both left DLPFC (p < 0.001) and M1 (p < 0.001). CT-adjusted SCD showed greater region-specific impact on left DLPFC rather than M1. The electric field induced by stimulation was consequently decreased with the increased SCD across normal aging and dementia groups. CONCLUSIONS: Age and dementia have differential impacts on the SCDs of left DLPFC and M1. The findings suggest that it is important to be aware of region-specific distance measures when conducting neuromodulation in individuals with old age and dementia.

Mental health of the old- and new-generation migrant workers in China: who are at greater risk for psychological distress?

Rural-to-urban migrant workers (MWs) are a large vulnerable population in China and, recently, the new-generation MWs (those born in 1980 or later) have become the majority of this population. Examining difference in the epidemiology of poor mental health between the new- and old-generation (those born before 1980) MWs would facilitate mental health promotion efforts. However, very few related studies are available and they produced conflicting findings. This study investigated intergenerational difference in prevalence and correlates of psychological distress (PD) in MWs. A total of 3031 MWs (691 old- and 2340 new-generation MWs) completed a standardized questionnaire containing socio-demographic, migration-related, and work-related variables and the Chinese 12-item General Health Questionnaire (GHQ-12). A GHQ-12 score of 3 or higher was used to denote PD. PD was more prevalent in the new- than old-generation MWs (36.2% versus 28.2%, P < 0.001). The elevated risk of PD in the new- versus old-generation remained significant after controlling for potential confounders (OR=1.51, P < 0.001). For the new-generation, correlates for PD included low monthly income, recent two-week physical morbidity, migrating alone, poor Mandarin proficiency and long working hours; while for the old-generation, correlates for PD included low education, recent two-week physical morbidity, and having worked in many cities. The new-generation MWs are at higher risk for PD than the old-generation MWs. Mental health services for addressing the generation-specific needs may be an effective way to prevent or reduce PD of MWs.

Beyond a Differential Diagnosis: Cognitive and Morphometric Decoding of Information Processing Speed in Senior Adults with DSM-5 Mild Neurocognitive Disorders.

BACKGROUND: Processing speed has been highlighted as a diagnostic item for neurocognitive disorders (NCD) in DSM-5. The utility of information processing speed (IPS) enclosed with multiscale constructs in the diagnosis of NCD warrants exploration. OBJECTIVE: We aimed to investigate the IPS with two types of measurements in the patients with NCD due to vascular disease (NCD-vascular) and NCD due to Alzheimer's disease (NCD-AD), and examine the associations between IPS measures and morphometric features. METHODS: The IPS was evaluated using trail making test (TMT) and flanker test (n = 204). Direct scores, derived scores, and reaction time (RT) were used as IPS measures. Further, surface-based morphometry cortical volume was calculated in a subsample (n = 44) with structural MRI data. RESULTS: All IPS measures showed a significant value to differentiate NCD patients from healthy subjects. Only mean RT could distinguish NCD-AD from NCD-vascular groups. TMT-B score and difference score were correlated with gray matter volume (GMV) of inferior frontal gyrus, precuneus and superior temporal cortex. Mean RT was associated with the GMV of post-central gyrus (r = -0.327, p = 0.035), and executive speed was associated with inferior frontal cortex (r = -0.475, p = 0.001), cingulate gyrus (r = -0.497, p = 0.001), and superior temporal gyrus (r = -0.36, p = 0.019). CONCLUSION: The cognitive and morphometric correlates of IPS measures indicate that complex IPS might be decomposed into the domain-specific components with corresponding neural underpinnings. Our findings may also provide essential insights into the diagnostic item of NCD.

'Two-level' measurements of processing speed as cognitive markers in the differential diagnosis of DSM-5 mild neurocognitive disorders (NCD).

Processing speed is an updated diagnostic factor for neurocognitive disorders (NCD) in DSM-5. This study investigated the characteristics of processing speed and their diagnostic values in NCD patients. A flanker test was conducted in 31 adults with NCD due to vascular disease (NCD-vascular), 36 patients with NCD due to Alzheimer's disease (NCD-AD), and 137 healthy controls. The processing speed was evaluated using two measurements: mean reaction time (RT) and intra-individual variability of RT. Mean RT represents the global processing speed. Intra-individual variability of RT is the short-term fluctuation of RT and consists of two indices, which are intra-individual coefficient of variation of reaction time (ICV-RT) and intra-individual standard deviations (iSD). We observed elevated ICV-RT and iSD in NCD-AD and NCD-vascular patients. Additionally, there was a slowed RT in NCD-AD patients. The intra-individual variability of RT had a moderate power to differentiate NCD subgroups. The mean RT was able to discriminate the NCD-AD from NCD-vascular patients. Our findings highlight the clinical utility of the combined 'two-level' measurements of processing speed to distinguish between individuals with different cognitive status. Furthermore, the 'two-level' features of processing speed embedded in the psychometric property may also reflect the diverse aetiology underlying certain 'disease-specific' neurocognitive disorders.

Aberrant interhemispheric functional connectivity within default mode network and its relationships with neurocognitive features in cognitively normal APOE ε 4 elderly carriers.

BACKGROUND: Default mode network (DMN) is vulnerable to the effects of APOE genotype. Given the reduced brain volumes and APOE ε 4-related brain changes in elderly carriers, it is less known that whether these changes would influence the functional connectivity and to what extent. This study aimed to examine the functional connectivity within DMN, and its diagnostic value with age-related morphometric alterations considered. METHODS: Whole brain and seed-based resting-state functional connectivity (RSFC) analysis were conducted in cognitively normal APOE ε 4 carriers and matched non-carriers (N=38). The absolute values of mean correlation coefficients (z-values) were used as a measure of functional connectivity strength (FCS) between DMN subregions, which were also used to estimate their diagnostic value by receiver-operating characteristic (ROC) curves. RESULTS: APOE ε 4 carriers demonstrated decreased interhemispheric FCS, particularly between right hippocampal formation (R.HF) and left inferior parietal lobular (L.IPL) (t=3.487, p<0.001). ROC analysis showed that the FCS of R.HF and L.IPL could differentiate APOE ε 4 carriers from healthy counterparts (AUC value=0.734, p=0.025). Moreover, after adjusting the impact of morphometry, the differentiated value of FCS of R.HF and L.IPL was markedly improved (AUC value=0.828, p=0.002). CONCLUSIONS: Our findings suggest that APOE ε 4 allele affects the functional connectivity within posterior DMN, particularly the atrophy-corrected interhemispheric FCS before the clinical expression of neurodegenerative disease.

Acculturative Stress of Chinese Rural-To-Urban Migrant Workers: A Qualitative Study.

BACKGROUND: Global literature has suggested a negative impact of acculturative stress on both physical and mental health among international migrants. In China, approximately 20 percent of its population is rural-to-urban migrant workers and there are significant cultural differences between rural and urban societies, but no data are available regarding the acculturative stress of Chinese migrant workers. This study aimed to explore the forms and contexts of acculturative stress among Chinese migrant workers. METHODS: Qualitative data were collected from four focus group discussions with 17 Chinese rural-to-urban migrant workers and three individual interviews with three medical professionals who provided mental health services for factory-workers in Shenzhen, China. RESULTS: The data in the current study showed that rural-to-urban migrant workers in China had experienced various forms of acculturative stress including difficulties in adapting to the environment, work-related stress, family-related stress, financial hardship, and lack of sense of belonging to cities. CONCLUSION: Rural-to-urban migration in China is a challenging transition with significant acculturative stress and demands for major adjustments among migrant workers. The assessment and management of acculturative stress is a necessary first step in providing mental health services to migrant workers.

Efficiency of Attentional Components in Elderly with Mild Neurocognitive Disorders Shown by the Attention Network Test.

AIMS: Complex attention, serving as a main diagnostic item of mild neurocognitive disorders (NCD), has been reported to be susceptible to pathological ageing. This study aimed to evaluate the attention network functions in older adults with subtypes of NCD. METHODS: 36 adults with NCD due to Alzheimer's disease (NCD-AD), 31 adults with NCD due to vascular disease (NCD-vascular) and 137 healthy controls were recruited. Attention Network Test (ANT) was conducted to assess the efficiency of alerting, orienting and executive control. RESULTS: Significant between-group differences were found in executive control (conventional score: F = 11.472, p < 0.001; ratio score: F = 8.430, p < 0.001) and processing speed (F = 4.958, p = 0.008). NCD subgroups demonstrated poorer performance on the ANT, particularly on executive control (healthy 59.9 ± 45.9, NCD-vascular 88.9 ± 44.8, NCD-AD 97.0 ± 53.9). Moreover, the NCD-AD group showed both less efficient executive control and prominent slowing processing speed (reaction time: healthy 687.5 ± 106.0 ms, NCD-vascular 685.3 ± 97.1 ms, NCD-AD 750.6 ± 132.6 ms). CONCLUSIONS: The NCD-vascular group appeared to be less efficient in executive control, while the NCD-AD group demonstrated less effective executive control and also slower processing speed. These results suggest that the characterized performance of ANT, processing speed and executive control in particular, might help differentiate adults at risk of different forms of cognitive impairment.

COHORT EFFECTS OF SUICIDE MORTALITY ARE SEX SPECIFIC IN THE RAPIDLY DEVELOPED HONG KONG CHINESE POPULATION, 1976-2010.

BACKGROUND: To examine temporal variations of age, period, and cohort on suicide mortality rate in Hong Kong (HK) from 1976 to 2010, and speculate the macroenvironmental mechanisms of the observed trends. METHODS: Poisson age-period-cohort modeling was used to delineate the effects of age, period, and cohort on suicide mortality. Analysis by sex was also conducted to examine if gender difference exists for suicidal behaviours. RESULTS: Age-cohort model provides the best fit to the mortality data, implying that the cohort effect is likely to explain more of the contributions to HK's suicide mortality pattern than the period effect. Risk of suicide mortality increases nonlinearly with age and accelerates after age 65-69 for both sexes. Moreover, the cohort effects differ between the sexes-risk of mortality increases continually for men born after 1961, but no change is observed for women since the 1941 cohort. CONCLUSIONS: With increased risk of suicide mortality in younger cohorts and the age effect of suicide mortality, we may see future increase in suicide mortality as these younger cohorts age. Further studies are needed to clarify plausible associations between broader sociohistorical changes in the population impacting psychological risk factors and suicidal behaviour to better inform suicide prevention strategies.

Disturbance of attention network functions in Chinese healthy older adults: an intra-individual perspective.

BACKGROUND: Intra-individual variability (IIV) and the change of attentional functions have been reported to be susceptible to both healthy ageing and pathological ageing. The current study aimed to evaluate the IIV of attention and the age-related effect on alerting, orienting, and executive control in cognitively healthy older adults. METHOD: We evaluated 145 Chinese older adults (age range of 65-80 years, mean age of 72.41 years) with a comprehensive neuropsychological battery and the Attention network test (ANT). A two-step strategy of analytical methods was used: Firstly, the IIV of older adults was evaluated by the intraindividual coefficient of variation of reaction time (ICV-RT). The correlation between ICV-RT and age was used to evaluate the necessity of subgrouping. Further, the comparisons of ANT performance among three age groups were performed with processing speed adjusted. RESULTS: Person's correlation revealed significant positive correlations between age and IIV (r = 0.185, p = 0.032), age and executive control (r = 0.253, p = 0.003). Furthermore, one-way ANOVA comparisons among three age groups revealed a significant age-related disturbance on executive control (F = 4.55, p = 0.01), in which oldest group (group with age >75 years) showed less efficient executive control than young-old (group with age 65-70 years) (Conventional score, p = 0.012; Ratio score, p = 0.020). CONCLUSION: Advancing age has an effect on both IIV and executive attention in cognitively healthy older adults, suggesting that the disturbance of executive attention is a sensitive indicator to reflect healthy ageing. Its significance to predict further deterioration should be carefully evaluated with prospective studies.

Associations between Intra-Individual Variability of Reaction Time and Cognitive Function in Cognitively Normal Senior Adults: Still beyond Good or Bad?

Background: Intra-individual (IIV) of reaction time (RT), as the short-term fluctuations of RT-based performance, has been reported to be susceptible to cognitive ageing. The current study aimed to examine IIV of RT and its relationships with cognitive performance in cognitively normal senior adults. Methods: We evaluated 137 community-dwelling elderly (mean age: 72.41 ± 3.99) with a comprehensive neuropsychological battery and a RT-based test. Intraindividual coefficient of variation of reaction time (ICV-RT) was used to evaluate the IIV. Pearson's correlation and hierarchical multiple regression analyses were employed to assess the relationships between IIV and the scores of cognitive function. Results: Advancing age was accompanied with declined cognitive function and increased IIV. ICV-RT was negatively correlated with the score of Montreal Cognitive Assessment Hong Kong version (HK MoCA) across three types of flanker. Hierarchical multiple regression showed that ICV-RT was a significant predictor of HK MoCA (ß = -0.294, p = 0.001). Conclusion: Increased IIV is consistently associated with and contributed to the age-related decline of cognitive performance in senior adults. The utility of IIV in predicting further deterioration should be carefully postulated with prospective studies.

Would transcranial direct current stimulation (tDCS) enhance the effects of working memory training in older adults with mild neurocognitive disorder due to Alzheimer's disease: study protocol for a randomized controlled trial.

BACKGROUND: There has been longstanding interesting in cognitive training for older adults with cognitive impairment. In this study, we will investigate the effects of working memory training, and explore augmentation strategies that could possibly consolidate the effects in older adults with mild neurocognitive disorder. Transcranial direct current stimulation (tDCS) has been demonstrated to affect the neuronal excitability and reported to enhance memory performance. As tDCS may also modulate cognitive function through changes in neuroplastic response, it would be adopted as an augmentation strategy for working memory training in the present study. METHODS/DESIGN: This is a 4-week intervention double-blind randomized controlled trial (RCT) of tDCS. Chinese older adults (aged 60 to 90 years) with mild neurocognitive disorder due to Alzheimer's disease (DSM-5 criteria) would be randomized into a 4-week intervention of either tDCS-working memory (DCS-WM), tDCS-control cognitive training (DCS-CC), and sham tDCS-working memory (WM-CD) groups. The primary outcome would be working memory test - the n-back task performance and the Chinese version of the Alzheimer's Disease Assessment Scale - Cognitive Subscale (ADAS-Cog). Secondary outcomes would be test performance of specific cognitive domains and mood. Intention-to-treat analysis would be carried out. Changes of efficacy indicators with time and intervention would be tested with mixed effect models. DISCUSSION: This study adopts the theory of neuroplasticity to evaluate the potential cognitive benefits of non-invasive electrical brain stimulation, working memory training and dual stimulation in older adults at risk of cognitive decline. It would also examine the tolerability, program adherence and adverse effects of this novel intervention. Information would be helpful for further research of dementia prevention studies. TRIAL REGISTRATION: ChiCTR-TRC- 14005036 Date of registration: 31 July 2014.