Cognitive and emotional effects of carotid stenosis

PRINCIPLES Patients with carotid artery stenosis (CAS) are at risk of ipsilateral stroke and chronic compromise of cerebral blood flow. It is under debate whether the hypo-perfusion or embolism in CAS is directly related to cognitive impairment. Alternatively, CAS may be a marker for underlying risk factors, which themselves influence cognition. We aimed to determine cognitive performance level and the emotional state of patients with CAS. We hypothesised that patients with high grade stenosis, bilateral stenosis, symptomatic patients and/or those with relevant risk factors would suffer impairment of their cognitive performance and emotional state. METHODS A total of 68 patients with CAS of ≥70% were included in a prospective exploratory study design. All patients underwent structured assessment of executive functions, language, verbal and visual memory, motor speed, anxiety and depression. RESULTS Significantly more patients with CAS showed cognitive impairments (executive functions, word production, verbal and visual memory, motor speed) and anxiety than expected in a normative sample. Bilateral and symptomatic stenosis was associated with slower processing speed. Cognitive performance and anxiety level were not influenced by the side and the degree of stenosis or the presence of collaterals. Factors associated with less cognitive impairment included higher education level, female gender, ambidexterity and treated hypercholesterolemia. CONCLUSIONS Cognitive impairment and increased level of anxiety are frequent in patients with carotid stenosis. The lack of a correlation between cognitive functioning and degree of stenosis or the presence of collaterals, challenges the view that CAS per se leads to cognitive impairment.

Being optimally aroused matters: Effects of a weak stress manipulation on children’s executive functions are moderated by temperament and age

We tested a core assumption of the bidirectional model of executive function (EF) (Blair & Ursache, 2011) indicating that EF is dependent on arousal. From a bottom-up perspective the performance on EF tasks is assumed to be curvilinearly related to arousal, with very high or low levels of arousal impairing EF. N = 107 4-and 6-year-olds’ performance on EF tasks was explored as a function of a weak stress manipulation aiming to raise children’s emotional arousal. EF (Stroop, Flanker, Go/no-go, and Backwards Color Recall) was assessed and stress was induced in half of the children by imposing a mild social evaluative threat. Furthermore, children’s temperament was assessed as a potential moderator. We found that stress effects on children’s EF performance were moderated by age and temperament: 4-year-olds with high Inhibitory Control and high Attentional Focusing were negatively affected by the stressor. However, it is unclear whether these effects were mediated by self-reported arousal. Our findings disconfirmed the hypotheses that adverse effects of the stressor are particularly high in children high on emotional reactivity aspects of temperament and low on self-regulatory aspects of temperament. Further, 6-year-olds did not show any stress effects. Results will be discussed within the framework of the Yerkes-Dodson law and with regard to stress manipulations in children.

Cognitive and physiological effects of an acute physical activity intervention in elementary school children

The aim of the present study was to investigate the effects of an acute physical activity intervention that included cognitive engagement on executive functions and on cortisol level in young elementary school children. Half of the 104 participating children (6–8 years old) attended a 20-min sport sequence, which included cognitively engaging and playful forms of physical activity. The other half was assigned to a resting control condition. Individual differences in children's updating, inhibition, and shifting performance as well as salivary cortisol were assessed before (pre-test), immediately after (post-test), and 40 min after (follow-up) the intervention or control condition, respectively. Results revealed a significantly stronger improvement in inhibition in the experimental group compared to the control group, while it appeared that acute physical activity had no specific effect on updating and shifting. The intervention effect on inhibition leveled out 40 min after physical activity. Salivary cortisol increased significantly more in the experimental compared to the control group between post-test and follow-up and results support partly the assumed inverted U-shaped relationship between cortisol level and cognitive performance. In conclusion, results indicate that acute physical activity that includes cognitive engagement may have immediate positive effects on inhibition, but not necessarily on updating and shifting in elementary school children. This positive effect may partly be explained through cortisol elevation after acute physical activity.

Effect of Cognitive Impairment on Driving-Relevant Cognition in Older Persons

Intact cognitive abilities are fundamental for driving. Driving-relevant cognition may be affected in older drivers due to aging or cognitive impairment. The aim of this study was to investigate the effects of cognitive impairment on driving-relevant cognition in older persons. Performance in selective and divided attention, eye-hand-coordination, executive functions and the ability to regulate distance and speed of 18 older persons with CI-Group (cognitive impairment group) was compared to performance of older control group (18 age and gender-matched cognitively normal subjects) and young control group (18 gender-matched young subjects). The CI-Group showed poorer performance than the other two control groups in all cognitive tasks (significance level (p) < 0.001, effect size (partial η2) = 0.63). Differences between cognitively impaired and cognitively normal subjects were still significant after controlling for age (effect sizes from 0.14 to 0.28). Dual tasking affected performance of cognitively impaired subjects more than performance of the other two groups (p = 0.016, partial η2 = 0.14). Results show that cognitive impairment has age-independent detrimental effects on selective and divided attention, eye-hand-coordination, executive functions and the ability to regulate distance and speed. Largest effect sizes are found for reaction times in attention tasks.

Effectiveness of the cognitive differentiation program of the integrated psychological therapy: group versus individual treatment

The aim of the current pilot study was to compare two strategies in the application of the cognitive differentiation program of Integrated Psychological Therapy for people with schizophrenia. Twenty-six outpatients were randomly assigned to the application of the program in group sessions (CDg), or to its application in individualized sessions (CDi). The program provides cognitive exercises to promote better performance in cognition, and both groups of participants completed the same number of exercises following the same number of sessions per week. Outcomes were assessed on neuropsychological measures of attention, executive functioning and everyday memory, and everyday functioning. Effect sizes showed the absence of effects in everyday memory and social functioning, higher improvements in the CDi group in attention, and a higher improvement in the CDg condition in executive functioning. The results suggest that the program application model could be individualized, depending on patient-specific cognitive deficits.

Repetitive transcranial magnetic stimulation of the dorsolateral prefrontal cortex affects divided attention immediately after cessation of stimulation

Transcranial magnetic stimulation has evolved into a powerful neuroscientific tool allowing to interfere transiently with specific brain functions. In addition, repetitive TMS (rTMS) has long-term effects (e.g. on mood), probably mediated by neurochemical alterations. While long-term safety of rTMS with regard to cognitive functioning is well established from trials exploring its therapeutic efficacy, little is known on whether rTMS can induce changes in cognitive functioning in a time window ranging from minutes to hours, a time in which neurochemical effects correlated with stimulation have been demonstrated. This study examined effects of rTMS on three measures of executive function in healthy subjects who received one single rTMS session (40 trains of 2 s duration 20 Hz stimuli) at the left dorsolateral prefrontal cortex (DLPFC). Compared to a sham condition one week apart, divided attention performance was significantly impaired about 30-60 min after rTMS, while Stroop-interference and performance in the Wisconsin Card Sorting Test was unaffected after rTMS. Repetitive TMS of the left DLPFC, at stimulation parameters used in therapeutic studies, does not lead to a clinically relevant impairment of executive function after stimulation. However, the significant effect on divided attention suggests that cognitive effects of rTMS are not limited to the of acute stimulation, and may possibly reflect known neurochemical alterations induced by rTMS. Sensitive cognitive measures may be useful to trace those short-term effects of rTMS non-invasively in humans.

Cognitive functioning, behavior, and quality of life after stroke in childhood

Rationale: To provide a better understanding of cognitive functioning, motor outcome, behavior and quality of life after childhood stroke and to study the relationship between variables expected to influence rehabilitation and outcome (age at stroke, time elapsed since stroke, lateralization, location and size of lesion). Methods: Children who suffered from stroke between birth and their eighteenth year of life underwent an assessment consisting of cognitive tests (WISC-III, WAIS-R, K-ABC, TAP, Rey-Figure, German Version of the CVLT) and questionnaires (Conner's Scales, KIDSCREEN). Results: Twenty-one patients after stroke in childhood (15 males, mean 11;11 years, SD 4;3, range 6;10-21;2) participated in the study. Mean Intelligence Quotients (IQ) were situated within the normal range (mean Full Scale IQ 96.5, range IQ 79-129). However, significantly more patients showed deficits in various cognitive domains than expected from a healthy population (Performance IQ p = .000; Digit Span p = .000, Arithmetic's p = .007, Divided Attention p = .028, Alertness p = .002). Verbal IQ was significantly better than Performance IQ in 13 of 17 patients, independent of the hemispheric side of lesion. Symptoms of ADHD occurred more often in the patients' sample than in a healthy population (learning difficulties/inattention p = .000; impulsivity/hyperactivity p = .006; psychosomatics p = .006). Certain aspects of quality of life were reduced (autonomy p = .003; parents' relation p = .003; social acceptance p = .037). Three patients had a right-sided hemiparesis, mean values of motor functions of the other patients were slightly impaired (sequential finger movements p = .000, hand alternation p = .001, foot tapping p = .043). In patients without hemiparesis, there was no relation between the lateralization of lesion and motor outcome. Lesion that occurred in the midst of childhood (5-10 years) led to better cognitive outcome than lesion in the very early (0-5 years) or late childhood (10-18 years). Other variables such as presence of seizure, elapsed time since stroke and size of lesion had a small to no impact on prognosis. Conclusion: Moderate cognitive and motor deficits, behavioral problems, and impairment in some aspects of quality of life frequently remain after stroke in childhood. Visuospatial functions are more often reduced than verbal functions, independent of the hemispheric side of lesion. This indicates a functional superiority of verbal skills compared to visuospatial skills in the process of recovery after brain injury. Compared to the cognitive outcome following stroke in adults, cognitive sequelae after childhood stroke do indicate neither the lateralization nor the location of the lesion focus. Age at stroke seems to be the only determining factor influencing cognitive outcome.

Spatio-temporal dynamics of alpha brain electric fields, and cognitive modes

Brian electric activity is viewed as sequences of momentary maps of potential distribution. Frequency-domain source modeling, estimation of the complexity of the trajectory of the mapped brain field distributions in state space, and microstate parsing were used as analysis tools. Input-presentation as well as task-free (spontaneous thought) data collection paradigms were employed. We found: Alpha EEG field strength is more affected by visualizing mentation than by abstract mentation, both input-driven as well as self-generated. There are different neuronal populations and brain locations of the electric generators for different temporal frequencies of the brain field. Different alpha frequencies execute different brain functions as revealed by canonical correlations with mentation profiles. Different modes of mentation engage the same temporal frequencies at different brain locations. The basic structure of alpha electric fields implies inhomogeneity over time — alpha consists of concatenated global microstates in the sub-second range, characterized by quasi-stable field topographies, and rapid transitions between the microstates. In general, brain activity is strongly discontinuous, indicating that parsing into field landscape-defined microstates is appropriate. Different modes of spontaneous and induced mentation are associated with different brain electric microstates; these are proposed as candidates for psychophysiological ``atoms of thought''.

Repetitive transcranial magnetic stimulation: a putative add-on treatment for major depression in elderly patients.

Repetitive transcranial magnetic stimulation (rTMS) is a recent putative treatment for affective disorders. Several studies have demonstrated antidepressant effects of rTMS in younger patients; we aimed to assess its effect in older outpatients with treatment-resistant major depression. Twenty-four outpatients (mean age=62 years, S.D.=12) with major depression were randomized for sham or real stimulation and received 10 daily rTMS sessions (20 Hz, 2-s trains, 28-s intertrain intervals, 100% of motor threshold) in addition to the antidepressant medication. For sham stimulation, the coil was tilted 90 degrees. Depression severity was assessed using the Hamilton Depression Rating Scale, the Beck Depression Inventory, items from the NIMH self-rated symptom scale, and a visual analog depression scale. Mini-Mental Status Examination performance, memory, and executive and attentional functions were measured to control for cognitive side effects. Depression ratings revealed significant antidepressant effects within 2 weeks in both sham and real stimulation groups; however, there were no between-group differences. Treatment with rTMS was safe; adverse events were rare and not more prevalent in either group, and cognitive assessment did not show any deterioration. We were unable to demonstrate any additional antidepressant effects of real stimulation in elderly patients with treatment-resistant major depression. Therapeutic effects of rTMS in this clinically challenging patient group remain to be demonstrated.

Language and executive functioning: Children’s benefit from induced verbal strategies in different tasks

The interplay of language and cognition in children’s development has been subject to research for a long time. The present study followed up on recently reported deleterious effects of articulatory suppression on children’s executive functioning (Fatzer & Roebers, 2012), aiming to provide more empirical evidence on the differential influence of language on executive functioning. In the present study, verbal strategies were induced in three executive functioning tasks. The tasks were linked to the three central executive functioning dimensions of updating (Complex Span task), shifting (Cognitive Flexibility task) and inhibition (Flanker task). It was expected that the effects of the verbal strategy instruction would counter the results of articulatory suppression and thus be strong in the Complex Span task, weak but present in the Cognitive Flexibility task and small or nonexistent in the Flanker task. N = 117 children participated in the study, with n = 39 four-year-olds, n = 38 six-year-olds, and n = 40 nine-year-olds. As expected, results revealed a benefit from induced verbal strategies in the Complex Span and the Cognitive Flexibility task, but not in the Flanker task. The positive effect of strategy instruction declined with increasing age, pointing to more frequent spontaneous and self-initiated use of verbal strategies over the course of development. The effect of strategy instruction in the Cognitive Flexibility task was unexpectedly strong in the light of the only small detrimental effect of articulatory suppression in the preceding study. Implications for language’s involvement in the different executive functioning dimensions and for practice are discussed.