Attentional Reserve Research Articles

Functional cognitive disorder affects reaction time, subjective mental effort and global metacognition.

We previously hypothesized that functional cognitive disorder is characterized by heightened subjective mental effort, exhausted attentional reserve and metacognitive failure. To test this hypothesis, we administered a Stroop colour-word task in which attentional demand was varied by task difficulty (congruent versus incongruent cues) and the presence of a secondary auditory stimulus (passive or active listening to an oddball-type paradigm). We measured subjective mental effort, objective performance (reaction times and accuracy), metacognition and EEG-based biomarkers of mental workload. We tested 19 functional cognitive disorder patients and 23 healthy controls. Patients reported higher levels of depression, anxiety, fatigue, pain, sleep disruption, dissociation and obsessiveness. They rated their memory as significantly poorer than healthy controls; however, accuracy did not differ between groups in any condition. In contrast to healthy controls, patients rated their performance as poorer on the congruent Stroop task with background noise compared to silent conditions. Functional cognitive disorder was consistently associated with slower reaction times but this was not exacerbated by increased attentional demand. Patients but not healthy controls reported greater mental workload in noisy conditions but EEG biomarkers were similar between groups, regardless of task difficulty. Functional cognitive disorder has significant syndromic overlap with mood disorders and chronic fatigue and pain. It is associated with global metacognitive failure whereas local (task-specific) metacognition is only selectively impaired. Patients were slower than healthy controls, which might contribute to the 'brain fog' reported in this condition. Although subjective mental effort was increased in noisy conditions, we found no evidence of attentional exhaustion in functional cognitive disorder. Our results indicate that functional cognitive disorder is a multisystem condition affecting reaction time, subjective mental effort and global metacognition.

Cerebral cortical networking for mental workload assessment under various demands during dual-task walking.

While several studies have examined attentional reserve (via event-related potentials) and mental effort (via EEG spectral content) from various cortical regions during dual-task walking, none have assessed changes in the magnitude of interregional (cortico-cortical) communication as a measure of mental workload. Therefore, by deploying a traditional montage of electrode sites centered over the motor planning region as well as a more comprehensive graph theory-based approach encompassing the entire scalp, this study aimed to systematically examine changes in the magnitude of functional connectivity underlying cortico-cortical communication to assess changes in mental workload under various levels of challenge. Specifically, the Weighted Phase Lag Index (WPLI) was computed to assess the changes in magnitude of functional connectivity as participants performed a cognitive task under two demands (low and high) and two conditions (seated and walking). The results revealed enhanced fronto-centro-temporo-parietal theta connectivity during dual-task walking relative to being seated as well as a reduced inhibition of fronto-centro-temporo-parieto-occipital alpha networking as the demand on the secondary cognitive task increased. Collectively, these findings may reflect greater recruitment of task relevant processes to respond to increased cognitive-motor demands and thus an elevation of mental workload in an effort to maintain performance under varying levels of challenge. This work has the potential to inform future mental workload assessment applications in patient populations, including those who employ prostheses during cognitive-motor performance under various taskdemands.

Combined assessment of attentional reserve and cognitive-motor effort under various levels of challenge with a dry EEG system.

A novel ERP approach was proposed to index variations in mental workload, particularly in attentional reserve, which is complementary to EEG spectral content thought to reflect mental effort. To our knowledge, no study has assessed mental effort and attentional reserve simultaneously in EEG gel-based and, importantly, dry systems, which are particularly well suited for real-world settings. Therefore, by systematically considering ERP, EEG spectral, and importantly the combination of both, this study examined if a small set of dry EEG electrodes could detect changes in both spectral and ERP metrics to assess the mental workload under various challenges with a similar fidelity to their gel-based counterparts in a laboratory setting. By employing both EEG gel-based and dry systems, the ERP and spectral markers were computed while participants executed a visuomotor task under three levels of challenge. For both EEG systems, more challenging levels of difficulty were associated with concomitant changes in ERP amplitude, and spectral power reflected a reduction of the attentional reserve and an increase in cognitive-motor effort, respectively. Those variations in attentional reserve and cognitive-motor effort collectively indexed mental workload with nearly identical fidelity for both gel-based and dry EEG systems. These findings promise to assess the mental workload in situations where the use of dry EEG systems could be advantageously employed to examine human cognitive-motor performance.

Measurement of attentional reserve and mental effort for cognitive workload assessment under various task demands during dual-task walking

Previous work focused on cognitive workload assessment suggests EEG spectral content and component amplitudes of the event-related potential (ERP) waveform may index mental effort and attentional reserve, respectively. Although few studies have assessed attentional reserve and mental effort during upper-extremity performance, none have employed a combined approach to measure cognitive workload during locomotion. Therefore, by systematically considering ERPs, spectral content and importantly their combination, this study aimed to examine whether concurrent changes in spectral content and ERPs could collectively serve as an index of cognitive workload during locomotion. Specifically, ERP and EEG biomarkers were assessed as participants performed a cognitive task under two levels of difficulty (easy or hard) and two conditions (seated or walking). Changes in attentional reserve and mental effort appeared to collectively index cognitive workload under varying demands due to changes in task difficulty or performance conditions. This work can inform cognitive workload assessment in patient populations with gait deficiencies for future applications.

Empirical evidence for the relationship between cognitive workload and attentional reserve

While the concepts of cognitive workload and attentional reserve have been thought to have an inverse relationship for some time, such a relationship has never been empirically tested. This was the purpose of the present study. Aspects of the electroencephalogram were used to assess both cognitive workload and attentional reserve. Specifically, spectral measures of cortical activation were used to assess cognitive workload, while amplitudes of the event-related potential from the presentation of unattended “novel” sounds were used to assess attentional reserve. The relationship between these two families of measures was assessed using canonical correlation. Twenty-seven participants performed a flight simulator task under three levels of challenge. Verification of manipulation was performed using self-report measures of task demand, objective task performance, and heart rate variability using electrocardiography. Results revealed a strong, negative relationship between the spectral measures of cortical activation, believed to be representative of cognitive workload, and ERP amplitudes, believed to be representative of attentional reserve. This finding provides support for the theoretical and intuitive notion that cognitive workload and attentional reserve are inversely related. The practical implications of this result include improved state classification using advanced machine learning techniques, enhanced personnel selection/recruitment/placement, and augmented learning/training.

25 A systematic review of “brain fogs”: are these functional cognitive disorders?

<h3>Objective</h3> The term “functional cognitive disorder” (FCD) has been proposed to describe a subjective experience of cognitive dysfunction in the absence of underlying brain pathology. Features of FCD include discrepancies between cognitive symptoms and objective performance, memory perfectionism, over-interpretation of attentional lapses and heightened self-monitoring for cognitive errors. Fibromyalgia and non-cognitive functional neurological disorders (FND) such as non-epileptic attacks (NEA) can be associated with subjective cognitive symptoms, sometimes referred to as “brain fog”. The relationship between archetypal FCD and cognitive symptoms in the context of fibromyalgia and FND is unclear. We conducted a systematic review of cognitive findings in fibromyalgia and FND in order to define their key neuropsychological hallmarks. Our hypothesis was that the cognitive profile associated with functional motor and pain syndromes (i.e. brain fogs) will be similar to that seen in isolated FCD. <h3>Method</h3> We performed a systematic review of studies evaluating cognition in fibromyalgia and FND. We identified 56 studies on fibromyalgia and 40 studies on FND. Study characteristics were highly heterogeneous. <h3>Results</h3> A high frequency of cognitive symptoms was described in fibromyalgia but no consistent neuropsychological deficits were seen. However, some authors found memory symptoms to correlate with attentional abnormalities (in particular tests of divided attention), and these to pain. In NEA problems with memory and attention were also reported. However, most studies comparing NEA with epilepsy did not report generalised neuropsychological differences. Discrepancies between cognitive symptoms and objective performance were rarely investigated, and evidence was inconsistent. Effort testing was rarely included in neuropsychological assessment, particularly in fibromyalgia. However, only a minor proportion of patients failed on effort testing. Notably, effort definition and assessment tools were highly variable. “Memory perfectionism” was not evaluated. <h3>Conclusion</h3> Both fibromyalgia and FND appear to show prominent cognitive symptoms. Regarding objective performance, reduced attentional reserve has been postulated to explain symptoms such as distractibility and attentional lapses. Evidence for discrepancies between cognitive symptoms and objective performance, and for poor effort on testing, remains contradictory. Overall, although limited, the data suggest that the neuropsychological mechanisms underlying ”brain fog” are similar to those in isolated FCD.

The Relationship Between Engagement and Neurophysiological Measures of Attention in Motion-Controlled Video Games: A Randomized Controlled Trial.

BackgroundVideo games and virtual environments continue to be the subject of research in health sciences for their capacity to augment practice through user engagement. Creating game mechanics that increase user engagement may have indirect benefits on learning (ie, engaged learners are likely to practice more) and may also have direct benefits on learning (ie, for a fixed amount of practice, engaged learners show superior retention of information or skills).ObjectiveTo manipulate engagement through the aesthetic features of a motion-controlled video game and measure engagement’s influence on learning.MethodsA group of 40 right-handed participants played the game under two different conditions (game condition or sterile condition). The mechanics of the game and the amount of practice were constant. During practice, event-related potentials (ERPs) to task-irrelevant probe tones were recorded during practice as an index of participants’ attentional reserve. Participants returned for retention and transfer testing one week later.ResultsAlthough both groups improved in the task, there was no difference in the amount of learning between the game and sterile groups, countering previous research. A new finding was a statistically significant relationship between self-reported engagement and the amplitude of the early-P3a (eP3a) component of the ERP waveform, such that participants who reported higher levels of engagement showed a smaller eP3a (beta=−.08, P=.02).ConclusionsThis finding provides physiological data showing that engagement elicits increased information processing (reducing attentional reserve), which yields new insight into engagement and its underlying neurophysiological properties. Future studies may objectively index engagement by quantifying ERPs (specifically the eP3a) to task-irrelevant probes.

Psychophysiological support of increasing attentional reserve during the development of a motor skill

The aim of this study was to determine the relationship between motor skill and attentional reserve. Participants practiced a reaching task with the dominant upper extremity, to which a distortion of the visual feedback was applied, while a control group performed the same task without distortion. Event-related brain potentials (ERPs), elicited by auditory stimuli were recorded throughout practice. Performance, as measured by initial directional error, was initially worse relative to controls and improved over trials. Analyses of the ERPs revealed that exogenous components, N1 and P2, were undifferentiated between the groups and did not change with practice. Notably, amplitude of the novelty P3 component, an index of the involuntary orienting of attention, was initially attenuated relative to controls, but progressively increased in amplitude over trials in the learning group only. The results provide psychophysiological evidence that attentional reserve increases as a function of motor skill acquisition.

Brain biomarkers based assessment of cognitive workload in pilots under various task demands.

Cognitive workload is an important element of cognitive-motor performance such as that exhibited during the piloting of an aircraft. Namely, an increase in task demands on the pilot can elevate cognitive information processing and, thus, the risk of human error. As such, there is a need to develop methods that reliably assess mental workload in pilots within operational settings. The present study contributes to this research goal by identifying physiological and brain biomarkers of cognitive workload and attentional reserve during a simulated aircraft piloting task under three progressive levels of challenge. A newly developed experimental method was employed by which electroencephalography (EEG) was acquired via a dry (i.e., gel-free sensors) system using few scalp sites. Self-reported responses to surveys and piloting performance indicators were analyzed. The findings revealed that as the challenge (task demands) increased, the perceived mental load increased, attentional reserve was attenuated, and task performance decreased. Such an increase in task demands was also reflected by changes in heart rate variability (HRV), as well as in the amplitude of the P300 component of event-related potentials to auditory probes, and in the spectral power of specific EEG frequency bands. This work provides a first step towards a long-term goal to develop a composite system of biomarkers for real-time cognitive workload assessment and state assessment of pilots in operational settings.

The effects of team environment on cerebral cortical processes and attentional reserve.

Despite the frequency with which individuals perform in team environments of differing quality as well as the robust relationship between cerebral cortical processes/ attentional reserve and cognitive–motor performance, the impact of team environment on cortical processes and attentional reserve has not been investigated. The purpose of the present study was to address this shortcoming. Using electroencephalography (EEG), we found that individuals exhibited reduced cerebral cortical activation and increased attentional reserve when performing in adaptive and neutral team environments as compared with a maladaptive team environment. Additionally, in the adaptive team environment, individuals exhibited superior cognitive–motor task performance relative to neutral and maladaptive team environments. Thus, the results suggest that relative to neutral team environments, maintaining performance in maladaptive team environments comes at the expense of neural and attentional resources, whereas adaptive team environments enhance performance without additional neurophysiological costs.

Effect of Task Modality on Dual-Task Performance, Response Time, and Ratings of Operator Workload

The purpose of this study was to use established measures of attentional reserve capacity to test for the existence of tactile-specific resources in the context of Wickens’ (1984, 2002) Multiple Resource Theory. Participants performed a primary counting task in the tactile modality and were presented with a concurrent secondary attention task in the visual, auditory, and tactile modalities. The data indicate a significant difference in performance based on whether the dual-task conditions were performed crossmodally or unimodally, in terms of percent correct and response time to target stimuli. Specifically, participants performed significantly worse in tactile-tactile dual-task conditions, suggesting performance was degraded as a function of resource depletion. Furthermore, participants rated the unimodal dual-task conditions as significantly harder, using a subjective workload rating, than either of the dual-task crossmodal conditions, or the single task condition. The results suggest that task interference was a function of resource limitation rather than structural interference, providing direct empirical evidence supporting the inclusion of tactile resources in Wickens’ Multiple Resource Theory.

Effects of Secondary Loading Task Modality on Attentional Reserve Capacity

The purpose of the present study was to use a newly-developed measure of reserve attentional capacity to evaluate unitary versus multiple resource theories of attention. Participants performed a primary visual monitoring task and were presented with visual, auditory, and tactile secondary loading tasks. The data indicate that participants maintained performance on the primary task, as instructed, and performed the secondary task with any remaining attentional reserve capacity. A significant difference was found on the basis of secondary task modality, wherein performance on the visual secondary task was significantly worse than that of secondary auditory and tactile tasks. This result was additionally supported by scores on a subjective workload questionnaire. Although the data do not preclude interpretation in terms of a unitary resource model, data trends offer potential support for a multiple resource model.

Individual differences in cognitive synthesis: An M-capacity analysis

Individual differences in children's propensity to demonstrate cognitive synthesis were evaluated using an artificial reading task. Six-year-olds were asked to demonstrate the meaning of various sentences constructed of logographs, or whole-word symbols, which were arranged in either a meaningful (i.e., grammatical) or scrambled (i.e., ungrammatical) order. Some children demonstrated the sentences in a synthesized mode (expressing a single idea unit), while others used a nonsynthesized mode (expressing the meanings of individual logographs). Overall, synthesizers had a larger attentional reserve, or M-capacity, than nonsynthesizers. The two groups did not differ significantly in age, intellectual level, or reading achievement. As predicted by their larger M-capacity, synthesizers demonstrated from memory significantly more items from meaningful sentences than nonsynthesizers. However, when synthesizers attempted to integrate the scrambled sentences, the excessive operative schemes needed to reorganize the items reduced their recall performance to the level of nonsynthesizers.