Letter Cancellation Task Research Articles

Attentional Correlates of Colored Lights: Considerations for Cognitive Testing

Attention, an important index of cognitive function, can be affected amidst colored lights. This work investigated the effects of colored lights on the performance in attention task. Participants (N = 42) performed in one, two, and three letter cancellation task (LCT) during four lighting conditions. The order of LCT and the colored light sessions were randomized. The performance in LCT was evaluated through % accuracy, % omission, and % error. A repeated measures ANOVA showed a statistically significant difference in % accuracy in one LCT (F(2.46, 100.8) = 24.45, p < 0.001), two LCT (F(2.57, 105.4) = 20.53, p < 0.001), and three LCT (F(2.66, 109.22) = 17.96, p < 0.001) among the four colored lights. In addition, % omission revealed a statistically significant difference in one LCT (F(2.46, 100.8) = 24.43, p < 0.001), two LCT (F(2.57, 105.4) = 20.57, p < 0.001), and three LCT (F(2.66, 109.16) = 18.21, p < 0.001) among the four lights. There was no statistically significant difference in % error in one LCT (F(2.05, 84.1) = 1.23, p = 0.3), two LCT (F(2.66, 109.06) = 0.62, p = 0.971), three LCT (F(2.62, 107.53) = 0.97, p = 0.4) among the four lighting conditions. Colored lights affect attention-related cognitive processing. The attentional correlates of white and red lights are more compared to green, and blue lights. Lighting condition should be an important consideration for cognitive testing, for designing workspaces, educational settings, and other environments where attention plays a crucial role.

Normative scores for attentional tests used by the Spanish consortium for ageing normative data (SCAND) study: Trail Making Test, Digit Symbol and Letter Cancellation

Objective: This paper reports normative data for different attentional tests obtained from a sample of middle-aged and older native Spanish adults and considering effects of age, educational level and sex. Method: 2,597 cognitively intact participants, aged from 50 to 98 years old, participated voluntarily in the SCAND consortium studies. The statistical procedure included conversion of percentile ranges into scaled scores. The effects of age, education and sex were taken into account. Linear regressions were used to calculate adjusted scaled scores. Results: Scaled scores and percentiles corresponding to the TMT, Digit Symbol and Letter Cancellation Task are shown. Additional tables show the values to be added to or subtracted from the scaled scores, for age and education in the case of the TMT and Letter Cancellation Task measures, and for education in the case of the Digit Symbol subtest. Conclusions: The current norms provide clinically useful data for evaluating Spanish people aged 50 to 98 years old and contribute to improving detection of initial symptoms of cognitive impairment.

The Effects of Water Provision and Education on Students’ Hydration Status, Cognitive Abilities, and Fine Motor Function in A Full-Day Primary School

Background/aim: Dehydration due to inadequate water intake in children may disrupt brain functions. This study aimed to investigate the effects of hydration education with water provision on hydration status, cognitive functions and motor performance. Materials and Methods: Forty-eight children in primary full-day school (age 8 – 11 years) were recruited in this study. The intervention of hydration education was performed for two days, both for students and teachers. The water was provision for 12 days. Letter cancellation task (LCT), symbol digit modalities test (SDMT), and direct image different test (DIDT) were used to assess cognitive functions. Motor performance was evaluated using a finger tapping test (FTT). Hydration status was determined with urine specific gravity (USG) and urine color (UC). Before and after interventions, all parameters were evaluated.Results: Most students found dehydrated (&gt;65%). The students had lower USG and UC after the intervention and it was correlated with each other (before; rs=0.45, P = 0.001 and after; rs=0.82, P = 0.001). All cognitive and motor functions were significantly higher after an intervention (P &lt; 0.05). Conclusion: Hydration education to students and teachers combined with water provision at primary full-day school increases hydration status and enhances cognitive and fine motor skills.

Cardiovascular disease risk factors and cognitive functions in older Russian adults

Abstract Background The prevalence of cardiovascular diseases (CVD) is increasing due to the global trend towards an aging population. CVD and cerebrovascular disease have a negative impact on cognitive health, and CVD risk factors may also be associated with cognitive decline with aging. Purpose To investigate associations of modifiable risk factors for CVD with cognitive functions (CF) in older Russian adults. Methods A random population sample (3153 men and women, aged 55–84 years) was examined in our city in the 3rd wave of the Russian arm of the international project HAPIEE (Health, Alcohol, and Psychosocial Factors in Eastern Europe). We used standardized epidemiological and instrumental methods for assessment of risk factors, history and treatment of CVD. Cognitive tests included the assessment of memory indicators (immediate and delayed recall), semantic verbal fluency (animal naming), attention, concentration and processing speed (letter cancellation task). Associations between CVD risk factors and cognitive indices were analyzed cross-sectionally. Results Mean age in men was of 69.2±7.0 years (n=1198), in women - 69.7±6.9 (n=1955). In both sexes all cognitive domains were positively associated with education and negatively with age (p&amp;lt;0.001 for all cases). In men, after adjusting for health and lifestyle conditions, systolic blood pressure had inverse association with semantic verbal fluency (p=0.015); level of plasma glucose (p=0.003), waist-to-hip ratio (p=0.013) and smoking (p=0.028) were negative associated with letter cancellation task. In multivariate analyses in women, frequency of alcohol consumption (p&amp;lt;0.001 for all CF) and total cholesterol (p=0.042 for memory scores; p=0.001 for letter cancellation task) had positive relationship with CF indices, waist-to-hip ratio (p=0.002 for memory scores, p=0.038 for semantic fluency), level of plasma glucose (p=0.002 for memory scores, p&amp;lt;0.001 for letter cancellation task) and smoking (p&amp;lt;0.001 for letter cancellation task) had inverse relationships with cognition. Conclusion Our results show that metabolic risk factors (systolic blood pressure, plasma glucose, waist-to-hip ratio) and smoking had inverse relationship with CF indices in both sexes, and the level of blood lipids (total cholesterol and high-density lipoprotein cholesterol) and frequency of alcohol consumption (more pronounced in women) had positive associations with cognitive domains. These associations were independent from age. In multivariate analyses, some of these correlations were attenuated, and most associations were at least partly mediated by education. These findings highlight the importance of managing CVD risk factors to prevent cognitive decline. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Russian Foundation for Basic Research (20-313-90016),Russian Academy of Sciences (AAAA-A17-117112850280-2)

A night of sleep deprivation alters brain connectivity and affects specific executive functions

Sleep is a fundamental physiological process necessary for efficient cognitive functioning especially in relation to memory consolidation and executive functions, such as attentional and switching abilities. The lack of sleep strongly alters the connectivity of some resting-state networks, such as default mode network and attentional network. In this study, by means of magnetoencephalography (MEG) and specific cognitive tasks, we investigated how brain topology and cognitive functioning are affected by 24 h of sleep deprivation (SD). Thirty-two young men underwent resting-state MEG recording and evaluated in letter cancellation task (LCT) and task switching (TS) before and after SD. Results showed a worsening in the accuracy and speed of execution in the LCT and a reduction of reaction times in the TS, evidencing thus a worsening of attentional but not of switching abilities. Moreover, we observed that 24 h of SD induced large-scale rearrangements in the functional network. These findings evidence that 24 h of SD is able to alter brain connectivity and selectively affects cognitive domains which are under the control of different brain networks.

Effect of Combat Vehicle Operation on Cognitive Workload and Performance

Multifaceted stress factors related to infantry combat vehicle (ICV) operation may be considered as major a source of cognitive workload, which may significantly impact the performance of infantry soldiers. The available literature on the effect of ICV’s operational environment on soldier’s cognitive workload is scanty or mostly unreported. The present study was designed to observe the effect of ICV operation on the i) cognitive workload ii) cognitive performance and iii) to study the association between cognitive workload and performance. Thirty soldiers [mean(SD)- age: 31.86(2.9) years, weight: 74.40(7.7) kg, and height: 171.33(3.42) cm] volunteered for this study. Their heart rate (HR), heart rate variability (HRV) and respiratory frequency (RF) were recorded at three time points 00th-05th, 25th-30th and 55th-60th minute during the ICV operation. ‘A’ letter cancellation task (ALCT) was conducted to assess cognitive performance, before and after ICV operation. The internal temperature and relative humidity (RH) of ICV were assessed at same three time-points. Repeated measure ANOVA and Wilcoxon signed ranks test were conducted to observe significant changes in HR, HRV, RF, and cognitive performance. Association between HRV and ALCT was assessed using Pearson’s bivariate correlation. Changes were considered significant when p-value was ≤ 0.05. Significant increase in the HR and RF were observed along with significant decrease in both time and frequency domain of HRV after ICV operation. Similarly, ALCT showed a significant increase in the total and net score, and an increased error score in post-ICV operation. A strong positive correlation was observed between the ICV operation run-trial time and the increasing compartmental temperature (r=0.99) and RH (r=0.89). HRV components showed a negative correlation with ALCT measures. One hour of ICV operation resulted in increased cognitive workload and a significant decrease in the cognitive task performance. Internal temperature and RH of ICV are potential physical stress factors affecting the soldier’s workload and performance.

Consecutive and temporally distant perseverations after right brain damage: A prospective study.

Objective: Right brain-damaged patients may show omissions and/or additional marks in target cancellation. The latter is classified as perseverative behavior and has been attributed to defective response inhibition or attentional disengagement deficit. This study aimed at (a) verifying that consecutive (immediate) and return (temporally distant) motor perseverations could be due to different mechanisms; (b) investigating the relationships among different types of perseveration (e.g., consecutive, return, scribble), spatial neglect and the impairment in specific components of executive functioning. Method: Seventeen right brain-damaged patients underwent letter, star, bell, and apple cancellation tasks. A global index for each type of perseveration found and Mean Position of Hits, as a neglect index, were calculated. The following components of executive functioning were evaluated: motor programming (Frontal Assessment Battery [FAB] subtest), inhibitory control FAB, interference sensitivity (FAB and Stroop color-word interference test), set-shifting (Weigl sorting test, Phonemic/semantic alternate fluencies), and working memory (Backward Digit span). Results: Ten patients out of 17 showed some degree of perseveration. Regularized linear regression analyses demonstrated that interference sensitivity and Stroop test performances were related to return perseverations and backward digit to scribble ones. No significant relationships were found for consecutive perseverations and between neglect and any type of perseverations. Conclusions: The present study showed that return perseverations might have a distinct etiology from consecutive ones, being related to an inability to update and shift between action programs according to the visual stimuli. A finer classification of perseverations could help in unveiling the neuropsychological mechanisms underlying each type of behavior. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Immediate Effect of a Yoga Breathing Practice on Attention and Anxiety in Pre-Teen Children.

Pre-teen children face stressors related to their transition from childhood to adolescence, with a simultaneous increase in academic pressure. The present study compared the immediate effects of 18 min of (i) high frequency yoga breathing with (ii) yoga-based breath awareness and (iii) sitting quietly, on (a) attention and (b) anxiety, in 61 pre-teen children (aged between 11 and 12 years; 25 girls). Attention was assessed using a six letter cancellation task and Spielberger’s State Trait Anxiety Inventory STAI-S was used to measure anxiety before and after the three practices, practiced on separate days. Repeated measures ANOVA, followed by Bonferroni adjusted post-hoc analyses showed an increase in total attempts and net scores after high frequency yoga breathing (p < 0.05), while wrong attempts increased after yoga based breath awareness (p < 0.05). Anxiety decreased comparably after all three interventions. The 25 girls in the group had the same trend of results as the whole group with respect to the attention-based cancellation task, while boys showed no, how since change. For both girls and boys, anxiety decreased after all three 18min interventions. The results suggest that high frequency yoga breathing could be a short, useful school based practice to improve attention and reduce anxiety.

Deficient allo-centric visuospatial processing contributes to apraxic deficits in sub-acute right hemisphere stroke.

While visuospatial deficits are well-characterized cognitive sequelae of right hemisphere (RH) stroke, apraxic deficits in RH stroke remain poorly understood. Likewise, very little is known about the association between apraxic and visuospatial deficits in RH stroke or about the putative common or differential pathophysiology underlying these deficits. Therefore, we examined the behavioural and lesion patterns of apraxic deficits (pantomime of object use and bucco-facial imitation) and visuospatial deficits (line bisection and letter cancellation tasks) in 50 sub-acute RH stroke patients. Using principal component analysis (PCA), we characterized the relationship between the two deficits. We hypothesized that any interaction of these neuropsychological measures may be influenced by the demands of ego-centric/space-based and/or allo-centric/object-based processing. Contralesional visuospatial deficits were common in our clinically representative patient sample, affecting more than half of RH stroke patients. Furthermore, about one-third of all patients demonstrated apraxic deficits. PCA revealed that pantomiming and the imitation of bucco-facial gestures loaded clearly on a first component (PCA1), while letter cancellation loaded heavily on a second component (PCA2). For line bisection, overall mean deviation loaded on PCA1, while the difference between the mean deviations in contra- versus ipsilesional space loaded on PCA2. These results suggest that PCA1 represents allo-centric/object-based processing and PCA2 ego-centric/space-based processing. This interpretation was corroborated by the statistical lesion analyses with the component scores. Data suggest that disturbed allo-centric/object-based processing contributes to apraxic pantomime and imitation deficits in (sub-acute) RH stroke.

Is the Letter Cancellation Task a Suitable Index of Ego Depletion?

Abstract. The aim was to quantify ego depletion and measure its effect on inhibitory control. Adults ( N = 523) received the letter “e” cancellation ego depletion task and were subsequently tested on Stroop task performance. Difficulty of the cancellation task was systematically manipulated by modifying the text from semantically meaningful to non-meaningful sentences and words (Experiment 1) and by increasing ego depletion rule complexity (Experiment 2). Participants’ performance was affected by both text and rule manipulations. There was no relation between ego depletion task performance and subsequent Stroop performance. Thus, irrespective of the difficulty of the ego depletion task, Stroop performance was unaffected. The widely used cancellation task may not be a suitable inducer of ego depletion if ego depletion is considered as a lack of inhibitory control.

Let them sleep: The effects of a scheduled nap during the night shift on sleepiness and cognition in hospital nurses.

The aim of this study was to examine the effectiveness of a scheduled 30-min nap and its interaction with individual factors on sleepiness and cognition during an 8-hr night shift. This prospective, within-subjects study conducted between 2011-2014 compared sleepiness and cognition with/without a nap during the night shift, in 109 female nurses, tested on two nights with and two nights without a nap in counterbalanced order. Nurses completed the Munich ChronoType Questionnaire for Shiftwork, Pittsburgh Sleep Quality Index and Pre-Sleep Arousal Scale at study onset. They reported sleepiness hourly and performed the Digit Symbol Substitution and the Letter Cancellation Tasks at 3:00 and 7:00 a.m. They took a nap at 4:00 a.m. on nap nights and worked as usual on no-nap nights. Sleep-wake patterns were monitored using actigraphs 24hr before and during the shift. Caffeine consumption, workload and adverse events were reported. To assess the effectiveness of a scheduled nap, mixed-models and repeated measures analyses of variance were used. Lower levels of sleepiness were found at 5:00, 6:00 and 7:00 a.m. on nap versus no-nap nights. Increments in performance between 3:00-7:00 a.m. were significantly greater on nap versus no-nap nights for Digit Symbol Substitution Task correct responses and Letter Cancellation Task capacity. No interactions between the nap and any of the individual factors emerged. A scheduled nap provides an effective countermeasure against the negative consequences of night-time shift work in female nurses above and beyond interpersonal differences. Changes in attitude and policy are required to implement this beneficial and cost-effective strategy. ACTRN12618001857291.

Functional MRI of Letter Cancellation Task Performance in Older Adults.

The Letter Cancellation Task (LCT) is a widely used pen-and-paper probe of attention in clinical and research settings. Despite its popularity, the neural correlates of the task are not well understood. The present study uses functional magnetic resonance imaging (fMRI) and specialized tablet technology to identify the neural correlates of the LCT in 32 healthy older adults between 50–85 years of age, and further investigates the effect of healthy aging on performance. Subjects performed the LCT in its standard pen-and-paper administration and with the tablet during fMRI. Performance on the tablet was significantly slower than on pen-and-paper, with both response modes showing slower performance as a function of age. Across all ages, bilateral brain activation was observed in the cerebellum, superior temporal lobe, precentral gyrus, frontal gyrus, and occipital and parietal areas. Increasing age correlated with reduced brain activity in the supplementary motor area, middle occipital gyrus, medial and inferior frontal gyrus, cerebellum and putamen. Better LCT performance was correlated with increased activity in the middle frontal gyrus, and reduced activity in the cerebellum. The brain regions activated are associated with visuospatial attention and motor control, and are consistent with the neural correlates of LCT performance previously identified in lesion studies.

An Examination of Concentration and Mental Toughness in Professional Basketball Players

This study was carried out to investigate the concentration and mental toughness of professional basketball players. A total of 290 professional basketball players aged 16–26 years who played in the Turkish Basketball First and Second Leagues participated in the study. The “Sport Mental Toughness Questionnaire (SMTQ-14)” developed by Sheard et al. (2009) was used to determine mental toughness levels of the basketball players participating in the study, and the “Letter Cancellation Task” scale developed by Kumar and Telles (2009) was used to determine their concentration levels. Data were analyzed by using the Kolmogorov-Smirnov test, an independent samples t-test, and one-way analyses of variance (ANOVA).Results show that the concentration ability of the basketball players did not significantly differ in terms of gender, age and sports age. There were statistically significant differences in overall mental toughness, confidence and control. The players’ mental toughness and confidence scores differed significantly based on sports age. It is interesting to find that overall mental toughness was higher in the basketball players with a sports age of 1–5 years. According to their positions in the play, the players’ concentration ability was found to be significantly different between guards and pivots in favor of the guards. The concentration ability of the players playing at the guard position was higher than that of the players playing at other positions. Overall mental toughness and its sub-dimensions had no significant differences according to the positions. However, it is striking that overall mental toughness scores and its sub-dimension scores were high in guards and pivots.

PB10. Apraxic deficits in sub-acute right hemisphere stroke result from deficient allo-centric visuo-spatial processing

While visuo-spatial deficits are well characterized cognitive sequelae of right hemisphere (RH) stroke, apraxic deficits in RH stroke remain poorly understood. Likewise, very little is known about the association between apraxic and visuo-spatial deficits in RH stroke or about the putative common or differential pathophysiology underlying these deficits. Therefore, we examined the behavioral and lesion patterns of apraxic deficits (pantomime of object use and bucco-facial imitation) and visuo-spatial deficits (line bisection and letter cancellation tasks) in 50 sub-acute RH stroke patients. Using principal component analysis (PCA), we characterized the relationship between the two deficits. We hypothesized that any interaction of these neuropsychological measures may be influenced by the demands of ego-centric/space-based and/or allo-centric/object-based processing. Contra-lesional visuo-spatial deficits were common in our clinically representative patient sample, affecting more than half of RH stroke patients. Furthermore, about one third of all patients demonstrated apraxic deficits. PCA revealed that pantomiming and the imitation of bucco-facial gestures loaded clearly on a first component (PCA1), while letter cancellation loaded heavily on a second component (PCA2). For line bisection, overall mean deviation loaded on PCA1, while the difference between the mean deviations in contra- versus ipsi-lesional space loaded on PCA2. These results propose that PCA1 represents allo-centric/object-based processing and PCA2 2 ego-centric/space-based processing. This interpretation was corroborated by the statistical lesion analyses with the component scores. Data suggest that apraxic pantomime and imitation deficits in RH stroke result, at least in part, from disturbed allo-centric/object-based processing.

Pain is not associated with cognitive decline in older adults: A four-year longitudinal study

The finding of a potential association between pain and cognitive decline is limited to a few cross-sectional studies with relatively samples. We therefore aimed to investigate whether the presence and severity of pain at baseline could predict a decline in cognitive function over four years of follow-up in the English Longitudinal Study of Ageing. At baseline, participants with no dementia who were “often troubled by pain” were considered to have pain. Pain severity was categorized as mild, moderate, or severe. Cognitive function was explored through verbal fluency (assessed by asking how many different animals the participants could name in 60 s), memory (sum of immediate and delayed verbal memory) and processing speed (number of target letters correctly identified on the letter cancellation task). Multivariable linear regression was used (exposure: pain; outcomes: cognitive change between follow-up and baseline, based on standardized residuals). Altogether, 6515 community-dwelling people with a mean age of 65 years (women = 57.3%) were included. Over a 4-year follow-up, after adjusting for 26 potential confounders, no association between pain (yes vs. no) and verbal fluency (beta = 0.02; 95%CI: −0.15 to 0.18), memory (0.05; 95%CI: −0.28 to 0.38), or processing speed (0.55; 95%CI: −18.4 to 2.93) at follow-up was found. Only severe pain was associated with greater decline in memory (−0.36; 95%CI: −0.68 to −0.04). In conclusion, in older people, pain was not associated with worsening in cognition, except for severe pain, which was marginally associated with worsening in memory tests. Further longitudinal studies are needed to confirm or refute our findings.

Age at menopause and lifetime cognition: Findings from a British birth cohort study.

ObjectiveWe investigated whether cognitive performance between ages 43 and 69 years was associated with timing of menopause, controlling for hormone replacement therapy, childhood cognitive ability, and sociobehavioral factors.MethodsWe used data from 1,315 women participating in the Medical Research Council National Survey of Health and Development (a British birth cohort study) with known age at period cessation and up to 4 assessments of verbal memory (word-learning task) and processing speed (letter-cancellation task) at ages 43, 53, 60–64, and 69. We fitted multilevel models with linear and quadratic age terms, stratified by natural or surgical menopause, and adjusted for hormone replacement therapy, body mass index, smoking, occupational class, education, and childhood cognitive ability.ResultsVerbal memory increased with later age at natural menopause (0.17 words per year, 95% confidence interval [CI]: 0.07–0.27, p = 0.001); an association remained, albeit attenuated, after full adjustment (0.09, 95% CI: 0.02–0.17, p = 0.013). Verbal memory also increased with later age at surgical menopause (0.16, 95% CI: 0.06–0.27, p = 0.002), but this association was fully attenuated after adjustment. Search speed was not associated with age at menopause.ConclusionOur findings suggest lifelong hormonal processes, not just short-term fluctuations during the menopause transition, may be associated with verbal memory, consistent with evidence from a variety of neurobiological studies; mechanisms are likely to involve estrogen receptor β function. Further follow-up is required to assess fully the clinical significance of these associations.

Yoga therapy for sustained attention

Background: Sustained attention (SA) is a vital function mediated by the right frontal-parietal cortex. The six letter cancellation task (SLCT) measures SA. Assessment of SA in volunteers undergoing Yoga therapy (YT) training compared to control group is the theme of the present study. Materials and Methods: Sixty healthy volunteers, 48.75 ± 3.86 years of mean age were participated in the present study. Thirty volunteers selected from Swami Vivekananda Yoga Anusandhana Samsthana University, Bengaluru, India were practiced YT for 7 days. They were compared with a control group of 30 healthy volunteers from Sri Devaraj Urs Medical College, Kolar, India matched for the duration of the study, age, gender, and socioeconomic background that were not exposed to YT training but continued their usual college routine during that period. All volunteers were assessed for SA using SLCT. Results: The YT group showed 18.06% significant increase (P = 0.010, paired samples t-test) in total attempted (TA) score on SLCT. Similarly, there was 19.03% significant increase (P = 0.008, paired samples t-test) in net score (NS). However, there was 26.32% decrease in wrongly attempted (WA) score which was statistically not significant (P = 0.637, paired samples t-test). There was no significant change in control group. Increase in TA and NS and decrease in WA is related with enhancement of SA. Conclusion: The results suggest that YT enhances SA in healthy volunteers. Additional well-designed trial with long-term follow-up is needed before a strong recommendation can be made.

0514 SIX MONTHS OF CONTINUOUS POSITIVE AIRWAY PRESSURE TREATMENT IMPROVES NEUROBEHAVIORAL FUNCTION AND QUANTITATIVE SLEEP ELECTROENCEPHALOGRAM MEASURES IN OBSTRUCTIVE SLEEP APNEA

Untreated obstructive sleep apnea (OSA) is associated with neurobehavioral deficits and altered brain electrophysiology. We evaluated the effect of continuous positive airway pressure (CPAP) treatment on quantitative electroencephalogram (EEG) measures during sleep and cognitive function in OSA. We studied 162 OSA patients (age 50 ± 13, AHI 35.0 ± 26.8) before and after 6 months of CPAP treatment. Neurobehavioural tests were performed to assess working memory (2-back and 3-back accuracy), sustained attention (Psychomotor Vigilance Task, PVT), visual-spatial scanning (Letter Cancellation Task, LCT) and executive function (Stroop). All participants attended the sleep laboratory for overnight PSG at baseline and after CPAP. Power spectral analysis was performed on all-night EEG data (C3/M2) in a sub-set of 90 participants. Slow wave activity (SWA, absolute delta EEG power) and spindle frequency activity (SFA, sigma EEG power) in NREM sleep and a measure of EEG slowing in REM were calculated. Spindle density (events p/min) & characteristics (duration, amplitude, frequency) in stage N2 sleep were also derived using an automated spindle event detection algorithm. All outcomes analysed as change from baseline, and are mean [95%CI] or median [IQR]. Six months of CPAP improved neurobehavioural function across all cognitive domains: 2-back (accuracy: 4.5[24%], p<0.0001); 3-back (accuracy: 6[24%], p<0.0001); and PVT (mean slowest 10% RRT: 0.12[0.8], p=0.002) LCT (average hits: 3.8[8.5], p<0.0001) and Stroop colour (accuracy: 2.0[19.2%], p<0.0001). In our sub-set, CPAP increased SWA (105.3[61.7–148.8µV2], p<0.0001) and SFA (1.50[0.70–1.18], p=0.0003) in NREM. CPAP significantly increased sleep spindle density (p=0.003), spindle duration (p=0.019) and amplitude (p<0.0001). Associations between baseline sleep EEG and change in performance with CPAP were found with less SWA in NREM and improved sustained attention on the PVT(rho=0.24, p=0.03) and greater EEG slowing in REM and improved working memory(rho=0.25, p=0.01). Six months of CPAP improved performance and enhanced sleep EEG features. Reduced SWA in NREM and greater EEG slowing in REM at baseline showed the greatest improvement in some measures of performance with CPAP. Sleep EEG measures via PSG may provide information on which patients are most at risk of neurobehavioural dysfunction. Australian National Health and Medical Research Council Project Grant 57355.

Game theoretical mapping of causal interactions underlying visuo-spatial attention in the human brain based on stroke lesions.

Anatomical studies conducted in neurological conditions have developed our understanding of the causal relationships between brain lesions and their clinical consequences. The analysis of lesion patterns extended across brain networks has been particularly useful in offering new insights on brain-behavior relationships. Here we applied multiperturbation Shapley value Analysis (MSA), a multivariate method based on coalitional game theory inferring causal regional contributions to specific behavioral outcomes from the characteristic functional deficits after stroke lesions. We established the causal patterns of contributions and interactions of nodes of the attentional orienting network on the basis of lesion and behavioral data from 25 right hemisphere stroke patients tested in visuo-spatial attention tasks. We calculated the percentage of damaged voxels for five right hemisphere cortical regions contributing to attentional orienting, involving seven specific Brodmann Areas (BA): Frontal Eye Fields, (FEF-BA6), Intraparietal Sulcus (IPS-BA7), Inferior Frontal Gyrus (IFG-BA44/BA45), Temporo-Parietal Junction (TPJ-BA39/BA40), and Inferior Occipital Gyrus (IOG-BA19). We computed the MSA contributions of these seven BAs to three behavioral clinical tests (line bisection, bells cancellation, and letter cancelation). Our analyses indicated IPS as the main contributor to the attentional orienting and also revealed synergistic influences among IPS, TPJ, and IOG (for bells cancellation and line bisection) and between TPJ and IFG (for bells and letter cancellation tasks). The findings demonstrate the ability of the MSA approach to infer plausible causal contributions of relevant right hemisphere sites in poststroke visuo-spatial attention and awareness disorders. Hum Brain Mapp 38:3454-3471, 2017. © 2017 Wiley Periodicals, Inc.

Retinal Nerve Fiber Layer Measures and Cognitive Function in the EPIC-Norfolk Cohort Study.

PurposeWe examined the relationship between retinal nerve fiber layer (RNFL) thickness and cognitive function in a population of older British adults.MethodsParticipants of the European Prospective Investigation of Cancer (EPIC) Norfolk cohort study underwent ophthalmic and cognitive assessment. Measurements of RNFL thickness were made using the Heidelberg Retina Tomograph (HRT). Cognitive testing included a short form of the Mini-Mental State Examination (SF-MMSE), an animal naming task, a letter cancellation task, the Hopkins Verbal Learning Test (HVLT), the National Adult Reading Test (NART), and the Paired Associates Learning Test. Multivariable linear regression models were used to assess associations of RNFL thickness with cognitive test scores, adjusted for age, sex, education level, social class, visual acuity, axial length, and history of cataract surgery.ResultsData were available from 5563 participants with a mean age of 67 years. A thicker HRT-derived RNFL thickness was associated with better scores for the SF-MMSE (0.06; 95% confidence interval [CI], [0.02, 0.10], P = 0.005), HVLT (0.16, 95% CI [0.03, 0.29]; P = 0.014), and NART (−0.24, 95% CI [−0.46, −0.02], P = 0.035). The associations of RNFL thickness with SF-MMSE and HVLT remained significant following further adjustment for NART.ConclusionsWe found a significant association between HRT-derived RNFL thickness and scores from cognitive tests assessing global function, recognition, learning, episodic memory, and premorbid intelligence. However, the associations were weak and not currently of predictive value. Further research is required to confirm and clarify the nature of these associations, and identify biological mechanisms.