Transcranial direct current stimulation of dorsolateral prefrontal cortex improves dual-task gait performance in patients with Parkinson’s disease: A double blind,sham-controlled study

BackgroundDespite advances in pharmacological treatments and surgical processes, the problem of impaired dual-tasking persists in people with Parkinson’s disease (PD). Recently, transcranial direct current stimulation (tDCS) applied to the dorsolateral prefrontal cortex (DLPFC) has shown the potential to improve dual-task walking.Research QuestionCan combining left DLPFC stimulation using tDCS with dual-task performance reduce the cost of dual-tasking in individuals with PD?MethodsWe conducted a sham-controlled, cross-over, and double-blind study to investigate the effect of combining tDCS with the dual-task walk and its sustained effects among people with PD. Twenty participants with PD completed two sessions (anodal or sham tDCS) with at least a 1-week gap. Stimulation involved transferring 2 mA current through the left DLPFC for 30 min. Single- and dual-task gait was assessed before, during, immediately after, 15, and 30 min after stimulation ceased. Phoneme verbal fluency task was given as the cognitive distractor during dual task.Results and ConclusionThe results of this study show that in the dual-task condition, participants walked faster at fifteen minutes (p = 0.017) and thirty minutes (p < 0.01) after anodal tDCS ceased compared to sham. Similarly, participants generated a higher number of words per minute at fifteen minutes (p = 0.017), and thirty minutes (p < 0.01) after anodal tDCS ceased compared to sham. Furthermore, the dual-task cost (DTC) associated with gait speed was significantly lower (p = 0.022) at fifteen minutes after anodal tDCS compared to sham tDCS. However, no significant effect of tDCS was observed on gait and cognitive performance under the single-task condition. In conclusion, left DLPFC stimulation can improve dual-tasking in participants with PD and the peaking of the tDCS effect was observed at fifteen minutes after stimulation ceased.     

Sleep,sedentary activity,physical activity,and cognitive function among older adults: The National Health and Nutrition Examination Survey, 2011–2014

ObjectivesWe aimed to estimate the association of sleep, sedentary activity and physical activity with cognitive function among older adults, with consideration of the competing nature between variables of activity status.DesignCross-sectional study.MethodsA total of 3086 older adults (60 years or older) in the 2011–2014 National Health and Nutrition Examination Survey were included. The Global Physical Activity Questionnaire was used to measure self-reported time for sedentary activity, walking/bicycling and moderate-to-vigorous physical activity (MVPA). Cognitive function was examined using the CERAD Word Learning subtest (memory), Digit Symbol Substitution Test (executive function/processing speed), and Animal Fluency Test (language). Sleep duration was obtained via interview. Isotemporal substitution models using multivariable linear regression were applied to examine the associations of replacing sleep, sedentary activity, walking/bicycling, MVPA with each other and cognitive function, stratified by sleep duration per night (≤7 h, >7 h).ResultsAmong participants with sleep duration ≤7 h/night, replacing 30 min/day of sedentary activity with 30 min/day of MVPA or 30 min/day was associated with better cognition. Among participants with sleep duration >7 h/night, replacing 30 min/day of sleep with 30 min/day of sedentary activity, walking/bicycling, or MVPA was associated with better cognition.ConclusionsReplacing sedentary activities with MVPA was associated with favorable cognitive function among older adults sleeping no longer than 7 h/night, and replacing excessive sleep with sedentary or physical activities was associated with favorable cognition. Future research is expected to examine the associations of replacing different activity status on long-term cognitive outcomes in longitudinal studies.     

Disentangling the mediating role of modifying interpretation bias on emotional distress using a novel cognitive bias modification program

BackgroundNegative interpretation bias is a potential risk factor for emotional disorders. In this study, we tested a clinically inspired 4-session online Cognitive Bias Modification-Interpretation (CBM-I_Clin) program to modify negative interpretation biases.MethodsWe randomized one hundred and twenty-one volunteer young adults (Mean age = 21.6 years, SD = 3.5; 85 % women) with varying levels of emotional distress to either an experimental or waitlist control group. Mediation analyses were used to disentangle the associations between the intervention, changes in interpretation biases (assessed by both a self-report and an experimental task), and changes in measures of cognitive vulnerability and symptoms of depression and anxiety.ResultsThe results showed that the CBM-I_Clin could change negative interpretation biases. Also, it had a direct effect on the change in negative memory bias, an indirect effect on the change in depression symptoms via the change in interpretation bias, and both direct and indirect effects on the change in self-reported dysfunctional attitudes.LimitationsThe study included a non-clinical sample of participants and it did not control for some potential confounding factors (e.g., attentional disorders). Furthermore, participants’ engagement during the sessions at home was not supervised.ConclusionsThe CBM-I_Clin is a potential tool to prevent and intervene in emotional disorders in young adults and could complement other traditional CBM procedures or clinical interventions.     

On the physiology of cognitive decline in type 1 diabetes

ObjectivesType 1 diabetes mellitus (T1DM) may be associated with cognitive impairment and notably a decline in psychomotor speed, information processing speed and attention. The mechanism for this decline is uncertain. Previous studies by our group and others have demonstrated a decline in EEG-power and event-related potential amplitude in T1DM. The objectives of the present study were to explore whether 1) the association between event-related potential (N100) amplitude and psychomotor speed is different between T1DM and healthy subjects, and 2) the decline in N100 amplitude depends on duration of diabetes.MethodsPatients with T1DM (N = 204) and healthy control subjects (N = 358) were included in a cross-sectional study. Event-related brain potentials were recorded with auditory reaction tasks. Psychomotor speed was evaluated with the Grooved Pegboard test in a subset of the patients (N = 70) and the healthy control subjects (N = 89).ResultsPatients with T1DM had a decrease in the N100 amplitude that correlated with a decline in psychomotor speed, longer duration of diabetes and increasing age. In healthy controls, the N100 amplitude did not decrease with age and the association between psychomotor speed and N100 amplitude was absent.ConclusionThe association between psychomotor speed and N100 amplitude is likely to be a specific trait for T1DM since it was not found in healthy controls and was dependent on diabetes duration. Our findings indicate that the pathogenesis of cognitive decline in T1DM may involve a disease-related factor with a long-term influence on the N100 amplitude.     

Association between sleep quality and subjective cognitive decline: evidence from a community health survey

ObjectivesLittle is known concerning whether subjective cognitive decline (SCD) is associated with sleep quality. This study aimed to identify the association between self-reported quality of sleep and SCD in a large population of middle-aged and older adults in Korea.MethodsWe conducted this study based on data collected from the 2018 Korean Community Health Survey. Individuals aged 40 years and older who responded to the Behavioral Risk Factor Surveillance System (BRFSS) and Pittsburgh Sleep Quality Index (PSQI) assessments and did not lack data about multiple covariates were included. A total of 37,712 respondents with SCD and 135,119 those without SCD were included. Sleep quality was estimated using the PSQI, which includes seven self-reported components for sleep health assessment. SCD was assessed using the BRFSS. Logistic regression models adjusted for confounders were used to examine whether each component of the sleep quality index was related to SCD. Additional analysis of the correlation between quantified scores for each component and SCD-related functional limitations as ordinal variables was performed.ResultsThe mean age was 62.7 years in the SCD group and 56.4 years in the control group. In total, 13,777 (28.9%) respondents were male in the SCD group and 62,439 (50.7%) in the control group. The adjusted odds ratios of SCD were 1.25 for very bad sleep quality, 1.26 for long sleep latency, 1.16 for <5 h of sleep duration, 1.08 for <65% habitual sleep efficiency, 2.29 for high sleep disturbance, 1.26 for use of sleep medication ≥3 times a week, and 2.47 for high daytime dysfunction due to sleep problems compared to good sleep conditions. Furthermore, a higher score for each component of the sleep quality index correlated with greater SCD-related functional limitations.ConclusionsOur study provides evidence that poor sleep quality is closely related to both SCD and SCD-related functional limitations.     

Association between statin use and cognitive function: A systematic review of randomized clinical trials and observational studies

The US Food and Drug Administration issued a black box warning in 2012 regarding the association of statin use with cognitive impairment. This may deter patients and practitioners from using statins for guideline-directed indications. Large studies have not shown an increase in cognitive impairment with statin use. MEDLINE, EMBASE, and Cochrane databases were searched up to October 2019. We present an up-to-date systematic review of randomized controlled trials (RCTs) and prospective observational studies examining the association between statin use and cognitive status in a population aged ≥60 years. Twenty-four studies with 1,404,459 participants were included in the review. Twenty-one were prospective observational studies, and 3 were RCTs. All 3 RCTs, which ranged from 3.2 to 5.6 years of follow-up, showed no significant association between statin use and adverse cognitive effects (odds ratio [OR] 1.03 [0.82–1.30]) and (OR 1.0 [0.61–1.65]). The mean difference in the Mini-Mental State Examination was insignificant (0.06 [?0.04 to 0.16]) in the third RCT. The follow-up for observational studies ranged from 3 to 15 years. Ten observational studies showed reduced incidence of dementia. Seven showed no association with incident dementia. Three studies showed decline in cognition was similar, whereas one showed slower decline with statin use. There was no evidence of adverse cognitive effects, including incidence of dementia, deterioration in global cognition, or specific cognitive domains associated with statin use in individuals aged ≥60 years. Future studies should examine this association in studies with longer follow-up periods.     

Long-Term Abstinent Alcoholics Have Normal Memory

It is generally believed that many non-Korsakoff alcoholics have subtle defects in memory. To determine whether such defects vary as a function of length of abstinence (LOA), we performed extensive memory testing with: (1) recently detoxified (n = 31; LOA-29 days); (2) intermediate-term abstinent (n = 28; LOA = 1.9 years); (3) long-term abstinent (n = 32; LOA-7.0 years) alcoholics; and (4) nonalcoholic controls (n = 37). All subjects were matched on age and education. Alcoholics were matched on years of alcoholic drinking. Memory measures were divided into the following domains: verbal learning, verbal recall, visual learning, visual recall, and paired associate learning. A series of MANOVAs were conducted that revealed a significant relationship between visual learning and length of abstinence, and a significant interaction between age and length of abstinence on visual recall. Long-term abstinent subjects were not significantly different from controls on any test. We conclude that memory disturbance demonstrable among recently detoxified alcoholics in the early weeks of their abstinence is not evident in demographically matched long-term abstinent alcoholics with similar drinking histories.     

老年短暂性脑缺血患者颈动脉结构与血流动力学参数对认知功能的影响

目的：探讨老年短暂性脑缺血(TIA)患者颈动脉结构与血流动力学参数对认知功能的影响。方法48例老年TIA患者均接受超声检查,并接受简易精神状态检查(MMSE)评分及威斯康星卡片分类测验(WCST)评测。根据患者颈动脉狭窄程度将其分为无狭窄-轻度狭窄组(32例)及中重度狭窄组(16例),观察患者颈动脉狭窄及血流动力学指标,比较不同程度颈动脉狭窄患者MMSE评分及WCST各项指标的差异。结果(1)无狭窄-轻度狭窄者血流速度(PSV)显著高于中重度狭窄者,搏动指数(PI)、阻力指数(RI)显著低于中重度狭窄者,差异均有统计学意义(P<0.05);(2)无狭窄-轻度狭窄者MMSE评分为(27.65±7.86)分,显著高于中重度狭窄者的(24.56±6.54)分,差异有统计学意义(P<0.05);WCST各项指标比较,无狭窄-轻度狭窄者完成分类数、概念化水平显著高于WCST中重度狭窄者,错误应答数、持续性错误数及持续性应答数显著低于中重度狭窄者,差异均有统计学意义(P<0.05);(3)颈动脉狭窄程度与MMSE评分存在显著负相关(r=-0.393,P<0.05),与WCST指标持续性应答数间存在显著正相关(r=0.423,P<0.05)。血流动力学指标PSV与MMSE评分存在显著负相关(r=-0.411,P<0.05),与WCST指标持续性应答数间存在显著正相关(r=0.402,-0.05)。结论老年TIA颈动脉狭窄及血流动力学指标与其认知功能间关系密切,颈动脉狭窄程度越重,血流动力学指标改变越明显,患者认知功能障碍越严重。     

Investigating the age‐related “anterior shift” in the scalp distribution of the P3b component using principal component analysis

An age‐related “anterior shift” in the distribution of the P3b is often reported. Temporospatial principal component analysis (PCA) was used to investigate the basis of this observation. ERPs were measured in young and old adults during a visual oddball task. PCA revealed two spatially distinct factors in both age groups, identified as the posterior P3b and anterior P3a. Young subjects generated a smaller P3a than P3b, while old subjects generated a P3a that did not differ in amplitude from their P3b. Rather than having a more anteriorly distributed P3b, old subjects produced a large, temporally overlapping P3a. The pattern of the age‐related “anterior shift” in the P3 was similar for target and standard stimuli. The increase in the P3a in elderly adults may not represent a failure to habituate the novelty response, but may reflect greater reliance on executive control operations (P3a) to carry out the categorization/updating process (P3b).     

Speaking under pressure: Low linguistic complexity is linked to high physiological and emotional stress reactivity

What can a speech reveal about someone's state? We tested the idea that greater stress reactivity would relate to lower linguistic cognitive complexity while speaking. In Study 1, we tested whether heart rate and emotional stress reactivity to a stressful discussion would relate to lower linguistic complexity. In Studies 2 and 3, we tested whether a greater cortisol response to a standardized stressful task including a speech (Trier Social Stress Test) would be linked to speaking with less linguistic complexity during the task. We found evidence that measures of stress responsivity (emotional and physiological) and chronic stress are tied to variability in the cognitive complexity of speech. Taken together, these results provide evidence that our individual experiences of stress or “stress signatures”—how our body and mind react to stress both in the moment and over the longer term—are linked to how complex our speech under stress.